<figure><img src="image_217.png" /><figcaption>**Scheme 171.** The synthesis of D-lactoside-based crown ethers.</figcaption></figure>

Reaction with tetraethylene glycol ditosylate in the presence of potassium hydroxide gave **651** in 47% yield [267]. A second 18-crown-6 ether moiety was built onto the lactoside unit of **651** by hydrolysis of the acetonide protecting group and reaction with pentaethylene glycol ditosylate to give **652**. Taking advantage of a one pot procedure involving kinetic acetonation of **645** with 2-methoxypropene, benzylation and mild acid hydrolysis, the 6,6'-dihydroxy derivatives **646** was prepared with a 42% yield and then reacted with tetraethylene glycol ditosylate to afford **649** [270].

Finally, the synthesis of **650** required the preparation of the 3,3'-dihydroxy derivative **647**, which was obtained in a 9% overall yield via stannylation with dibutyltin oxide followed by treatment with allyl bromide, benzylation under phase transfer conditions and, finally, deallylation [267].

The same team reported the synthesis of the C₂-symmetric 18-crown-6 **656** and **657** featuring two lactoside units in the macrocycle. These compounds were both obtained from the mono-alkylated derivatives **653** and **654** by self-condensation of **653** or condensation of **653** and **654** (Scheme 172) [271].

<figure><img src="image_218.png" /><figcaption>**Scheme 172.** The synthesis of crown ethers containing two D-lactoside units.</figcaption></figure>
All crown ethers incorporating a lactoside unit, except **652**, catalysed the model Michael addition described in Scheme **166** with some enantioselectivity. The yields varied between 8% and 98% and the enantiomeric excesses between 7% and 70%. The authors demonstrated that, under the chosen conditions, no racemization took place. In addition, the **656** and **657** catalysts predominantly led to the (*R*)-enantiomer, while **649–651** favored the formation of the (*S*)-configured compound [271,272].

Following a totally different approach, oligoketoside-based crown ethers were prepared by Dondoni and Marra [273] from the di-, tri- and tetrasaccharidic ketosides obtained [274] from the already known [275] D-galacto-configured thiazolylketose [276] **660** (Scheme 173). The latter compound was prepared from the D-galactonolactone **659**, in turn, synthesised [275] by oxidation of the corresponding tetra-O-benzyl-galactopyranose (obtained by benzylation of methyl β-D-galactoside **658** and acid hydrolysis as described [277]) by the addition at low temperature of 2-lithiothiazole.

<figure><img src="image_219.png" /></figure>

**Scheme 173.** The synthesis of the glycosyl donor and glycosyl acceptor required for the preparation of the di-, tri- and tetrasaccharidic ketosides.

The key intermediate **660** was transformed into an efficient glycosyl donor, the anomeric phosphite **661**, as well as into the glycosyl acceptor **663** by acetylation, glycosidation with 4-penten-1-ol to give **662**, with a three-step conversion [278] of the thiazole ring into the formyl group through N-methylation, reduction to thiazolidine, silver-assisted hydrolysis, and hydride reduction to primary alcohol (Scheme 173).

The coupling of the phosphite **661** with the alcohol **663** in the presence of boron trifluoride afforded the corresponding thiazolyl-disaccharide as pure α-D anomer [274] (Scheme 174). The usual thiazole-to-aldehyde conversion, followed by reduction, led to the disaccharidic alcohol **664**, which was glycosylated with **663** and then transformed into the corresponding trisaccharidic alcohol **665**. Further iteration of the above reaction sequence gave the tetrasaccharide **666**.

<figure><img src="image_220.png" /></figure>

**Scheme 174.** The synthesis of the oligoketoside-based crown ethers.
To prepare the crown ether derivatives, the chain of 664–666 was elongated to afford 667–669 by reaction with bis(2-chloroethyl) ether and coupling of the resulting alkyl chlorides with ethylene glycol [273]. Upon *N*-iodosuccinimide activation of the anomeric pen-tenyl group, the alcohols 667–669 gave the benzylated cyclic *O*-glycosides 670–672. From these compounds, a second set of crown ethers (673–675) was obtained by hydrogenolysis and methylation (Scheme 174) [273].

The six crown ethers 670–675 were tested as chiral hosts in the model Michael addition (see Scheme 166) of methyl phenylacetate (two equiv.) to methyl acrylate in the presence of sodium or potassium *t*-butoxide in toluene at –78 °C to afford the adduct 627 in good to high isolated yield (60–94%) although the observed enantiomeric excesses were in general low or moderate (5–65%) [273]. It was found that the benzylated disaccharidic 15-crown-5 ether 670 gave the best results (*ee* = 55% in favour of (R)-627) when *t*-BuONa was employed, whereas its methylated analogue 673 was well suited for the use together with *t*-BuOK (65% *ee*) leading to the opposite enantiomer. Contrary to expectations, the trisaccharidic 18-crown-6 ethers 671 and 674 were not better hosts for the potassium cation (*ee* = 5% and 45%, respectively).

### 8.3. *Sugar Aza-Crown Ethers*

A large variety of monoaza-analogues of crown-ether were prepared, most of them featuring a side chain, which held additional coordinating sites. These structures were named nitrogen-pivot lariat ether by Gokel in reference to the use of a lasso in the American West [279]. The synthesis of this class of chiral crown ethers was based on alditols, glycals or aldoses with two free hydroxyl groups that were alkylated with bis(2-chloroethyl)ether in a liquid–liquid two-phase system (Scheme 175).

<figure><img src="image_221.png" /><figcaption>**Scheme 175.** The general synthetic approach to sugar-based aza-crown ethers.</figcaption></figure>

The exchange of chlorine to iodine atom was then performed with NaI to afford the bis-iodo derivatives whose reaction with primary amines in the presence of Na₂CO₃, gave the aza-crown ethers 678. In the particular case of the *N*-tosyl or NH derivatives the cyclisation was done from the bis-chloro derivatives using *p*-toluenesulfonamide in the presence of K₂CO₃. Treatment with sodium amalgam gave the free NH aza-crowns.

#### 8.3.1. Alditol-Based Aza-Crown Ethers

Following the general strategy described above, the mannitol-based aza-crown ethers 679a-j [280], 679k,l and 679m,n [254] were prepared from 1,2:5,6-di-O-isopropylidene-D-mannitol (593), 1,2:5,6-di-O-diphenylmethylidene-D-mannitol (599) [256] and 1,2:5,6-di-O-cyclohexylidene-D-mannitol (598) [255], respectively (Figure 44).

The di-O-isopropylidene-D-mannitol-based aza-crown ethers 679a-j were used as phase transfer catalysts in the Michael addition of 2-nitropropane to chalcone 602 [280]. Compounds 679a-j showed a low activity in this reaction conducted under two-phase liquid-liquid conditions since low yields (31–39%) were obtained after 48 h and the asymmetric induction was modest (6–67%). The best result (*ee* = 67% in favor of the (R)-enantiomer) was observed with the compound unsubstituted on the nitrogen atom 679j (38% yield).
<figure><img src="image_222.png" /><figcaption>**Figure 44.** Series of prepared mannitol-based aza-crown ethers.</figcaption></figure>

Concerning the nitrogen-substituted compounds, the best catalyst was the N-3-hydroxypropyl derivative **679e**, which led to the Michael adduct with a 39% yield and 40% enantiomeric excess [280]. The same crown ether was also used to catalyse the addition of nitropropane to other aromatic and heteroaromatic chalcone analogues, but the results were also modest and, in all cases, worse than those obtained with the D-glucose-based aza-crown ethers (see Michael additions in Section 8.3.3.2) [281]. Likewise, the crown ethers **679e** and **679i** (whose synthesis and characterization were not described) gave poorer results than their analogues derived from D-glucose in the epoxidation reaction of chalcones with *tert*-butylhydroperoxide (see Epoxidation of enones in Section 8.3.3.2) [282].

The aza-crown ethers **679k,l** and **679m,n** were used as catalysts in asymmetric Michael additions and in a Darzens condensation [254]. While the addition of diethyl acetoxy-malonate to *trans*-chalcone **602** required 10 days and gave **603** with a 24–39% yield and 11–38% enantiomeric excess, the Michael addition of diethyl acetamidomalonate to β-nitrostyrene (**604**) required 24–48 h and led to **605** with a 57–81% yield and 14–65% *ee*, the best asymmetric induction (*ee* = 65%) being obtained with the organocatalyst **679l**. The di-O-diphenylmethylidene protected aza-crowns **679k** and **679l** afforded the best results in the Michael-initiated ring closure reaction of diethyl bromomalonate with benzylidenemalonitriles. For instance, the cyclopropane **607** was obtained with 85% and 84% enantiomeric excess using catalysts **679k** or **679l**, respectively.

### 8.3.2. Glycal-Based Aza-Crown Ethers

Taking advantage of their extensive experience in the preparation of crown ethers and aza analogues, Bakó and co-workers prepared monoaza-15-crown-5 ethers using glycals obtained from L- and D-xylose and L- and D-arabinose [283]. The glycals **683** were obtained by conventional methods involving the preparation of the peracetylated glycosyl bromides **681**, which, when treated with activated zinc in acetic acid, gave rise to an elimination reaction (Scheme 176). After deprotection, the diols **683** were used as starting material to prepare the aza-crown ethers **684–687** (Figure 45) according to the general method described in Scheme 175.

<figure><img src="image_223.png" /><figcaption>**Scheme 176.** The general synthetic approach to deprotected glycals.</figcaption></figure>
<figure><img src="image_224.png" /><figcaption>**Figure 45.** Glycal-based aza-crown ethers prepared by Bakó and co-workers.</figcaption></figure>

The two enantiomeric pairs of lariat ethers were tested as phase transfer catalysts in liquid-liquid and solid-liquid systems for epoxidation, Michael or Darzens reactions [283] (Scheme 177). The epoxidation reaction of the chalcone **602** carried out with *tert*-butylhydro peroxide in a liquid-liquid two phases system gave exclusively the *trans*-epoxyketone **609**. Using the D-xylal-based catalyst **684**, the (2S,3R)-configured epoxyketone was obtained (77% *ee*), whereas the L-xylal-based macrocycle afforded the (2R,3S) enantiomer (72% *ee*). The D- or L-arabinal-based crown ethers **686** or **687** gave poor enantioselectivities (*ee* = 8 and 7%); however, in this case as well, the selectivity was reversed.

The same trend was observed for the Michael reaction between diethyl acetamidoma-
lonate and β-nitrostyrene **604**, which took place with modest enantiomeric excesses. On the
other hand, in the Darzens reaction involving α-chloroketones **688** and benzaldehyde, enan-
tiomeric excesses of 85 (2S,3R) and 91% (2R,3S) were observed for the *trans*-epoxyketones
**689** obtained from the phenyl-substituted 2-chloroindanone **688** (R = Ph) using the D- or
L-xylal-based catalyst **684** or **685**, respectively. Even if some enantiomeric excesses were
modest, this work is interesting because it demonstrated that the configuration of the sugar
unit annulated to the crown ether determined the stereochemical preference of the reaction.

<figure><img src="image_225.png" /><figcaption>**Scheme 177.** Epoxidations, Michael additions and Darzens reactions catalysed by **684–687**.</figcaption></figure>

8.3.3. Aldose-Based Aza-Crown Ethers

8.3.3.1. Synthesis

In most of the structures of the numerous aldose-based aza-crown ethers described,
the polyether chain is connected to the C-2 and C-3 atoms of variously protected α- or
β-glycosides. These aza-crown ethers were prepared through the general method outlined
in Scheme 175, i.e., reaction of the sugar diol with two (2-iodoethyl)ether chains followed
by coupling with primary amines. Starting from the 4,6-O-benzylidene derivative 65
(Scheme 178), a large number of lariat ethers 690, variously functionalized on the nitrogen
atom, were prepared this way (Table 2).
<figure><img src="image_226.png" /><figcaption>**Scheme 178.** The general synthesis of glucose-based aza-crown ethers (for R, see Table 2).</figcaption></figure>

<table><caption>**Table 2.** A series of glucose-based aza-crown ethers synthesised by Bakó and co-workers.</caption><thead><tr><th>Compound</th><th>R</th><th>Ref.</th><th>Compound</th><th>R</th><th>Ref.</th></tr></thead><tbody><tr><td>690a</td><td>H</td><td>[284]</td><td>690r</td><td>(CH<sub>2</sub>)<sub>4</sub>P(O)(OEt)<sub>2</sub></td><td>[285]</td></tr><tr><td>690b</td><td>butyl</td><td>[286]</td><td>690s</td><td>(CH<sub>2</sub>)<sub>5</sub>P(O)(OEt)<sub>2</sub></td><td>[285]</td></tr><tr><td>690c</td><td>decyl</td><td>[287]</td><td>690t</td><td>CH<sub>2</sub>P(O)(Ph)<sub>2</sub></td><td>[288]</td></tr><tr><td>690d</td><td>cyclohexyl</td><td>[287]</td><td>690u</td><td>(CH<sub>2</sub>)<sub>2</sub>P(O)(Ph)<sub>2</sub></td><td>[288]</td></tr><tr><td>690e</td><td>allyl</td><td>[289]</td><td>690v</td><td>(CH<sub>2</sub>)<sub>3</sub>P(O)(Ph)<sub>2</sub></td><td>[288]</td></tr><tr><td>690f</td><td>(CH<sub>2</sub>)<sub>2</sub>OH</td><td>[287]</td><td>690w</td><td>(CH<sub>2</sub>)<sub>4</sub>P(O)(Ph)<sub>2</sub></td><td>[288]</td></tr><tr><td>690g</td><td>(CH<sub>2</sub>)<sub>3</sub>OH</td><td>[286]</td><td>690x</td><td>(CH<sub>2</sub>)<sub>5</sub>P(O)(Ph)<sub>2</sub></td><td>[288]</td></tr><tr><td>690h</td><td>(CH<sub>2</sub>)<sub>4</sub>OH</td><td>[286]</td><td>690y</td><td>C<sub>6</sub>H<sub>5</sub></td><td>[287]</td></tr><tr><td>690i</td><td>CH<sub>2</sub>CH(OH)CH<sub>2</sub>OH</td><td>[289]</td><td>690z</td><td>CH<sub>2</sub>C<sub>6</sub>H<sub>5</sub></td><td>[287]</td></tr><tr><td>690j</td><td>(CH<sub>2</sub>)<sub>2</sub>OCH<sub>3</sub></td><td>[286]</td><td>690aa</td><td>(CH<sub>2</sub>)<sub>2</sub>C<sub>6</sub>H<sub>5</sub></td><td>[286]</td></tr><tr><td>690k</td><td>(CH<sub>2</sub>)<sub>3</sub>OCH<sub>3</sub></td><td>[289]</td><td>690ab</td><td>(CH<sub>2</sub>)<sub>3</sub>C<sub>6</sub>H<sub>5</sub></td><td>[289]</td></tr><tr><td>690l</td><td>(CH<sub>2</sub>)<sub>3</sub>O(CH<sub>2</sub>)<sub>2</sub>OCH<sub>3</sub></td><td>[289]</td><td>690ac</td><td>Ts</td><td>[284]</td></tr><tr><td>690m</td><td>(CH<sub>2</sub>)<sub>3</sub>N(CH<sub>3</sub>)<sub>2</sub></td><td>[289]</td><td>690ad</td><td>(CH<sub>2</sub>)<sub>3</sub>NHC(S)NHPh</td><td>[289]</td></tr><tr><td>690n</td><td>CH<sub>2</sub>CO<sub>2</sub>CH<sub>3</sub></td><td>[287]</td><td>690ae<sup>a</sup></td><td></td><td>[290]</td></tr><tr><td>690o</td><td>CH<sub>2</sub>P(O)(OEt)<sub>2</sub></td><td>[285]</td><td>690af</td><td></td><td>[291]</td></tr><tr><td>690p</td><td>(CH<sub>2</sub>)<sub>2</sub>P(O)(OEt)<sub>2</sub></td><td>[285]</td><td>690ag</td><td></td><td>[289]</td></tr><tr><td>690q</td><td>(CH<sub>2</sub>)<sub>3</sub>P(O)(OEt)<sub>2</sub></td><td>[285]</td><td>690ah<sup>a</sup></td><td></td><td>[290]</td></tr></tbody></table>

In order to facilitate the recycling of the catalyst, the supported glucose-based aza-15-crown-5 ether **690ai** was prepared from **690g** by reaction with 3-(triethoxysilyl)propyl isocyanate and then silica nanofibre [292] (Scheme 179).

<figure><img src="image_227.png" /><figcaption>**Scheme 179.** The synthesis of the supported glucose-based aza-15-crown-5 ether.</figcaption></figure>

Other aza-crown ethers incorporating a methyl α-D-glucoside unit were prepared from suitably protected glucosides (Figure 46). Using the methodology outlined in Scheme 175, **691g,k** and **692g,k** were obtained from methyl 4,6-O-isopropylidene-α-D-glucopyranoside or methyl 4,6-O-(1-naphthyl)methylene-α-D-glucopyranoside [293]. **696g,k** were obtained by hydrogenation of **690g,k** [293], while the N-tosyl derivative **696ac** was prepared by acid hydrolysis of **690ac** [284].

<footnote><sup>a</sup> aza-crown ethers **690ae** and **690ah** were characterised only by ¹H NMR analysis.</footnote>
<figure><img src="image_228.png" /><figcaption>**Figure 46.** Newly synthesised aza-crown ethers bearing a methyl α-D-glucoside moiety.</figcaption></figure>

The latter compound was also treated with NBS in the presence of BaCO₃ to afford **697ac**, which, upon treatment with sodium amalgam, gave **698a**. The methylated, butylated and acetylated N-tosyl derivatives **694ac**, **695ac** and **695ac** were obtained by alkylation or acylation of **696ac** and the cleavage of the tosyl group led to **693a**, **695a** and **694a** [284]. Alternatively, the butylated compound **695a** was also prepared from methyl 4,6-di-O-butyl-α-D-glucopyranoside [294] through the general method developed by Bakó and co-workers (Scheme 175). This approach made it possible to synthesize also the macrocycles **695b**, **k**, **z**, **aa** [294].

Following the general method described in Scheme 175, many other aza-crown ethers were prepared starting from the β-D-glucosides **699** [295], **700** [296] and **701** [297] (Scheme 180, Table 3) and from α- or β-D-galactosides (Scheme 181, Table 4).

<figure><img src="image_229.png" /><figcaption>**Scheme 180.** The general synthesis of aza-crown ethers bearing a β-D-glucoside moiety (for X, see Table 3).</figcaption></figure>

<table><caption>**Table 3.** A series of β-D-glucoside-based aza-crown ethers synthesised by Bakó and co-workers.</caption><thead><tr><th>Compound</th><th>X</th><th>Ref.</th><th>Compound</th><th>X</th><th>Ref.</th></tr></thead><tbody><tr><td>702aj</td><td><img src="image_0_0_2.png" alt="Chemical structure of 702aj"></td><td>[297]</td><td>703ak</td><td>CH<i>i</i>-Pr<sub>2</sub></td><td>[298,299]</td></tr><tr><td>703a</td><td>H</td><td>[300]<sup>a</sup></td><td>703al</td><td>CH<sub>2</sub>-<br>cyclohexyl</td><td>[298,299]</td></tr><tr><td>703b</td><td>butyl</td><td>[298,299]</td><td>703am</td><td>hexyl</td><td>[299]</td></tr><tr><td>703d</td><td>cyclohexyl</td><td>[298]<sup>a</sup></td><td>703an</td><td>(CH<sub>2</sub>)<sub>2</sub>CH<sub>3</sub></td><td>[301]<sup>a</sup></td></tr><tr><td>703f</td><td>(CH<sub>2</sub>)<sub>2</sub>OH</td><td>[298,299]</td><td>703ao</td><td>(CH<sub>2</sub>)<sub>4</sub>OCH<sub>3</sub></td><td>[301]<sup>a</sup></td></tr><tr><td>703g</td><td>(CH<sub>2</sub>)<sub>3</sub>OH</td><td>[298,299]</td><td>703ap</td><td></td><td>[301]</td></tr><tr><td>703j</td><td>(CH<sub>2</sub>)<sub>2</sub>OCH<sub>3</sub></td><td>[298,299]</td><td>703aq</td><td></td><td>[299]</td></tr><tr><td>703k</td><td>(CH<sub>2</sub>)<sub>3</sub>OCH<sub>3</sub></td><td>[299]</td><td>703ar</td><td></td><td>[299]</td></tr><tr><td>703z</td><td>CH<sub>2</sub>C<sub>6</sub>H<sub>5</sub></td><td>[298,299]</td><td>703as</td><td></td><td>[299]</td></tr><tr><td>703aa</td><td>(CH<sub>2</sub>)<sub>2</sub>C<sub>6</sub>H<sub>5</sub></td><td>[298,299]</td><td>704g</td><td>(CH<sub>2</sub>)<sub>3</sub>OH</td><td>[297]</td></tr><tr><td>703af</td><td><img src="image_0_0_3.png" alt="Chemical structure of 703af"></td><td>[301]<sup>a</sup></td><td>704aj</td><td><img src="image_0_0_4.png" alt="Chemical structure of 704aj"></td><td>[297]</td></tr><tr><td>703aj</td><td><img src="image_0_0_5.png" alt="Chemical structure of 703aj"></td><td>[301]</td><td></td><td></td><td></td></tr></tbody></table>

<footnote>a in some cases [298,300,301] the experimental procedures and analytical data were missing.</footnote>
<figure><img src="image_230.png" /><figcaption>**Scheme 181.** The general synthesis of aza-crown ethers bearing a D-galactoside moiety (for X, see Table 4).</figcaption></figure>

<table><caption>**Table 4.** A series of D-galactoside-based aza-crown ethers synthesised by Bakó and co-workers.</caption><thead><tr><th>Compound</th><th>X</th><th>Ref.</th><th>Compound</th><th>X</th><th>Ref.</th></tr></thead><tbody><tr><td>713b</td><td>butyl</td><td>[286]</td><td>714g</td><td>(CH<sub>2</sub>)<sub>3</sub>OH</td><td>[302]</td></tr><tr><td>713c</td><td>decyl</td><td>[287]</td><td>715g</td><td>(CH<sub>2</sub>)<sub>3</sub>OH</td><td>[302]</td></tr><tr><td>713g</td><td>(CH<sub>2</sub>)<sub>3</sub>OH</td><td>[303]</td><td>716g</td><td>(CH<sub>2</sub>)<sub>3</sub>OH</td><td>[302]</td></tr><tr><td>713j</td><td>(CH<sub>2</sub>)<sub>2</sub>OCH<sub>3</sub></td><td>[286]</td><td>717g</td><td>(CH<sub>2</sub>)<sub>3</sub>OH</td><td>[302]</td></tr><tr><td>713k</td><td>(CH<sub>2</sub>)<sub>3</sub>OCH<sub>3</sub></td><td>[303]</td><td>718g</td><td>(CH<sub>2</sub>)<sub>3</sub>OH</td><td>[302]</td></tr><tr><td>713z</td><td>CH<sub>2</sub>C<sub>6</sub>H<sub>5</sub></td><td>[287]</td><td>718aj</td><td>(CH<sub>2</sub>)<sub>3</sub>OCH<sub>3</sub></td><td>[297]</td></tr><tr><td>713aa</td><td>(CH<sub>2</sub>)<sub>2</sub>C<sub>6</sub>H<sub>5</sub></td><td>[286]</td><td>719g</td><td>(CH<sub>2</sub>)<sub>3</sub>OH</td><td>[302]</td></tr><tr><td>713aj</td><td>(CH<sub>2</sub>)<sub>2</sub>OCH<sub>3</sub></td><td>[297]</td><td>720g</td><td>(CH<sub>2</sub>)<sub>3</sub>OH</td><td>[302]</td></tr><tr><td>713as</td><td>(CH<sub>2</sub>)<sub>2</sub>OCH<sub>3</sub></td><td>[297]</td><td></td><td></td><td></td></tr></tbody></table>

Other aza-crown ethers were prepared from D-altrose (721) [304], D-mannose (722) [305], L-arabinose (723 and 724) [306], 2,6-dideoxy-D-ribo-hexopyranose (725) and 2-deoxy-D-ribo-hexopyranose (726) derivatives [307] (Figure 47). The sugar 3,4-diols required for the synthesis of 725 and 726 were both prepared from the epoxide 259 (see Scheme 155) through a four-step and two-step reaction sequence, respectively [307].

<figure><img src="image_231.png" /><figcaption>**Figure 47.** Aza-crown ether prepared by Bakó and co-workers from various glycosides.</figcaption></figure>

Another series of aza-crown ethers, featuring the nitrogen atom directly linked to the sugar unit, was prepared by regioselective epoxide opening of 569 with ethanolamine followed by cyclisation with tri- or tetraethylene glycol ditosylate to afford the altrose-based crown-amines 727 and 728 (Scheme 182) [307].
<figure><img src="image_232.png" /><figcaption>**Scheme 182.** The synthesis of the altrose-based crown-amines.</figcaption></figure>

Bakó and co-workers described another class of aza-crown ether featuring a pyridine ring in the macrocycle backbone in order to have a more rigid structure (Figure 48). The synthesis of **729** and **730** was conducted starting from methyl 4,6-O-benzylidene-α-D-glucopyranoside or 4,6-O-benzylidene-α-D-mannopyranoside, respectively, and 2,6-pyridine-dimethyl ditosylates [308].

<figure><img src="image_233.png" /><figcaption>**Figure 48.** Aza-crown ether containing a pyridine ring prepared by Bakó and co-workers.</figcaption></figure>

### 8.3.3.2. Catalysis

Having prepared a multitude of aza-crown ethers incorporating various monosaccharides and chains on the nitrogen atom, Bakó and co-workers published, in 2010, a review in which they gathered general conclusions about the effectiveness of these macrocycles on asymmetric catalysis for Michael reactions, epoxidation of enones or Darzens condensations [6]. Their conclusions are collated below and supplemented with more recent work.

#### Michael additions

The most studied Michael reaction was the addition of 2-nitropropane to chalcone **602**. The reaction was performed in a two-phase solid-liquid system using toluene as solvent in the presence of sodium *tert*-butoxide at room temperature (Scheme 183). As the catalyst, the above-described crown ethers containing α-D-glucoside (**690–698**, **729**), [281,284–286,288,289,293,294,308–313] β-D-glucoside (**703**) [298], α-D-mannoside (**722**, **730**) [305,308,309] or α-D-galactoside (**713**) [286] moieties were employed.

<figure><img src="image_234.png" /><figcaption>**Scheme 183.** The Michael addition catalysed by glucoside-, mannoside- and galactoside-based aza-crown ethers.</figcaption></figure>
Amongst these, the catalysts displaying a methyl α-glycoside protected by a benzylidene group in positions 4 and 6, conferring a certain rigidity to the monosaccharide, were the most efficient. Some results are given in Table 5. The comparison of the various monosaccharides incorporated in the aza-crown ethers allows to conclude that, concerning the enantioselectivity, the most effective is D-glucose followed by D-mannose, D-galactose and D-altrose. D-Glucopyranoside- and D-galactopyranoside-based macrocycles mainly gave the (R)-enantiomer while the mannoside-based aza-crown ethers led to the (S)-enantiomer (see the Table 5 footnote).

<table><caption>**Table 5.** The enantioselective Michael addition shown in Scheme 183.</caption><thead><tr><th>Entry</th><th>Catalyst</th><th>Time (h)</th><th>Yield (%)</th><th>ee (%)</th><th>Ref.</th></tr></thead><tbody><tr><td>1</td><td><b>690f</b></td><td>20</td><td>51</td><td>62 (R) <sup>a</sup></td><td>[286,313]</td></tr><tr><td>2</td><td><b>690g</b></td><td>28</td><td>53</td><td>85 (R) <sup>a</sup></td><td>[286,293,309]</td></tr><tr><td>3</td><td><b>690j</b></td><td>40</td><td>45</td><td>87 (R)</td><td>[286,310]</td></tr><tr><td>4</td><td><b>690t</b></td><td>48</td><td>39</td><td>60 (R)</td><td>[288]</td></tr><tr><td>5</td><td><b>690u</b></td><td>48</td><td>41</td><td>74 (R)</td><td>[288]</td></tr><tr><td>6</td><td><b>690v</b></td><td>48</td><td>32</td><td>77 (R)</td><td>[288]</td></tr><tr><td>7</td><td><b>690w</b></td><td>32</td><td>43</td><td>94 (R)</td><td>[285,288,310]</td></tr><tr><td>8</td><td><b>722f</b></td><td>44</td><td>32</td><td>70 (S)</td><td>[305]</td></tr><tr><td>9</td><td><b>722g</b></td><td>52</td><td>37</td><td>92 (S)</td><td>[305,309]</td></tr><tr><td>10</td><td><b>722h</b></td><td>58</td><td>40</td><td>63(S)</td><td>[305]</td></tr><tr><td>11</td><td><b>722k</b></td><td>50</td><td>37</td><td>77 (S)</td><td>[305]</td></tr><tr><td>12</td><td><b>713j</b></td><td>38</td><td>34</td><td>52 (R)</td><td>[286]</td></tr><tr><td>13</td><td><b>729a</b></td><td>24</td><td>48</td><td>72 (S)</td><td>[308]</td></tr><tr><td>14</td><td><b>729b</b></td><td>30</td><td>47</td><td>76 (S)</td><td>[308]</td></tr><tr><td>15</td><td><b>729c</b></td><td>30</td><td>51</td><td>67 (S)</td><td>[308]</td></tr><tr><td>16</td><td><b>730</b></td><td>25</td><td>50</td><td>80 (R)</td><td>[308]</td></tr></tbody></table>

The highest enantioselectivities were obtained with catalysts whose chain on the nitrogen atom ends with hydroxy or methoxy functions or is a phosphinoxidoalkyl chain. The length of the chain connecting the nitrogen atom to the terminal function had a great influence on the enantioselectivity. A three-carbon atom spacer proved to be the best choice for the chain ending with an alcohol function (Table 5, entries 1, 2, 8, 9 and 10), whereas the four-carbon atom chain connecting the phosphine oxide function proved to be optimal (Table 5, entries 4–7).

Other Michael reactions, such as the addition of malonates to *trans*-nitrostyrene **604** [289,292,302,304,311,312,314] or *trans*-chalcones [299], were conducted. For the addition of diethyl acetamidomalonate (Scheme 184), a high enantiomeric excess (99%) was observed using the glucopyranoside-based crown ether **690g** [311], while the galactose derivative **713k** or the 2-deoxy-D-ribose-based aza-crown ethers **725** and **726** gave poorer results [303,307]. This reaction was also performed in the presence of the silica nanofiber supported catalyst **690ai** [292] giving rise to (S)-**605** with 82% *ee* after 44 h. The authors claimed that this catalyst could be recovered by filtration and reused without regeneration, but no experimental data were given.

<footnote><sup>a</sup> Initially, the absolute configuration was erroneously assigned as (S) by NMR analysis on the basis of the chemical shifts in the presence of Eu(hfc)<sub>3</sub> observed for a crystalline compound whose structure was determined by X-ray diffraction [312]. The positive optical rotation of this compound was first attributed to the (S)-enantiomer [286,313] and then, without comments from the authors, to the (R)-enantiomer [293,309,310]. Therefore, doubts still exist about the stereochemical assignments given in certain articles.</footnote>
<figure><img src="image_235.png" /></figure>

The addition of glycine esters to various Michael acceptors was also achieved with more or less success [290,300,301].

### Cyclopropanation

The asymmetric Michael-initiated ring closure (MIRC) reaction has also been extensively studied by Bakó and co-workers. They developed this reaction of diethyl bromomalonate with chalcone (602), 2-arylidene-malononitriles (733), 2-benzylidene-1,3-diphenyl-1,3-propanediones (735) [303,315,316], 2-arylidene-1,3-indandiones (737) [316] and α-cyano-vinylsulfones (739) [297] under solid-liquid phase transfer catalytic conditions.

The reaction of bromomalonate with 602 was conducted employing the crown ethers incorporating an α-D-galactoside unit (713g and 713k) [303] or a methyl α-D-glucopyranoside unit 690g (Scheme 185) [315,316]. The reaction times were long (8 to 12 days) and the yields were moderate due to the formation of a few by-products. The *trans* isomer of the cyclopropane derivatives 732 was obtained with high diastereoselectivity (up to 98%). Enantiomeric excess of 98% or 99% using galactose-based macrocycles (713g and 713k) were obtained, whereas the crown ether incorporating a glucose unit 690g was less efficient with regard to enantioselectivity (ee = 88%). Other chalcones, substituted on the phenyl groups, gave poorer enantioselectivities.

<figure><img src="image_236.png" /></figure>

**Scheme 185.** The Michael-initiated ring closure reaction catalysed by sugar-based aza-crown ethers.

Cyclopropanation of 2-benzylidene-malononitriles 733 with diethyl 2-bromomalonate was also investigated using crown ethers incorporating a glucose (690g, 691g and 692g) [315,316], a mannose (722g), an altrose (721g) [316] or a galactoside unit (713g and 713k) [303] as catalysts. For the unsubstituted derivative (Scheme 186, R = H), the best catalysts were the galactose-based lariat ethers 713g and 713k that gave enantioselectivities of 67 and 78%, respectively, whereas the glucose-based crown ethers 690g, 691g and 692g afforded 734 with enantiomeric excesses of 32%, 29% and 30%, respectively.
<figure><img src="image_237.png" /><figcaption>**Scheme 186.** Cyclopropanation catalysed by sugar-based aza-crown ethers (nd: not determined).</figcaption></figure>

These results indicated that the 4,6-O-protecting group (benzylidene, isopropylidene or (1-naphthyl)methylene) had no significant impact on the asymmetric induction. The authors also showed that the results vary greatly with the substitution of the 2-benzylidene-malononitriles (Scheme 186).

The same catalysts were used for the MIRC reaction between diethyl bromomalonate and 2-benzylidene-1,3-diphenyl-1,3-propanediones **735** (Scheme 187) [303,315,316]. The cyclopropane derivative **736** was isolated in low to medium yields (34–67%). The highest enantioselectivity (76%) was obtained when the galactose-based catalyst **713k** was used.

<figure><img src="image_238.png" /><figcaption>**Scheme 187.** Cyclopropanation catalysed by sugar-based aza-crown ethers.</figcaption></figure>

The reaction of diethyl bromomalonate with 2-arylidene-1,3-indandiones **737** was also investigated in the presence of D-glucose, D-mannose- and D-altrose-based catalysts (Scheme 188) [316]. However, the cyclopropane derivatives **738** were obtained with moderate to low enantioselectivity.

<figure><img src="image_239.png" /><figcaption>**Scheme 188.** Cyclopropanation of 2-arylidene-1,3-indandiones catalysed by aza-crown ethers.</figcaption></figure>

In order to make maximum use of their phase transfer catalysts, Bakó and co-workers also studied the cyclopropanation reaction of α-cyano-vinylsulfones [297]. 4,6-O-Benzylidene-D-glucopyranoside- and D-galactopyranoside-based macrocycles were tested for the reaction of (E)-3-phenyl-2-(phenylsulfonyl)acrylonitrile (739) with diethyl bromomalonate (Scheme 189, Table 6). The *trans* cyclopropane **740** (i.e., bearing the phenyl and phenylsulfonyl groups on the opposite side of the ring) was obtained with enantiomeric excesses between 18 and 80%.
<figure><img src="image_240.png" /><figcaption>**Scheme 189.** The Michael-initiated ring closure reaction catalysed by sugar-based aza-crown ethers.</figcaption></figure>

<table><caption>**Table 6.** The Michael-initiated ring closure reaction shown in Scheme 189.</caption><thead><tr><th>Entry</th><th>Catalyst</th><th>Yield (%)</th><th>ee trans (%)</th></tr></thead><tbody><tr><td>1</td><td>690g</td><td>89</td><td>50</td></tr><tr><td>2</td><td>690aj</td><td>94</td><td>73</td></tr><tr><td>3</td><td>702aj</td><td>91</td><td>58</td></tr><tr><td>4</td><td>704g</td><td>88</td><td>18</td></tr><tr><td>5</td><td>704aj</td><td>90</td><td>35</td></tr><tr><td>6</td><td>713g</td><td>85</td><td>62</td></tr><tr><td>7</td><td>713aj</td><td>93</td><td>80</td></tr><tr><td>8</td><td>713ap</td><td>95</td><td>76</td></tr><tr><td>9</td><td>717g</td><td>93</td><td>61</td></tr><tr><td>10</td><td>718g</td><td>91</td><td>43</td></tr><tr><td>11</td><td>718aj</td><td>90</td><td>72</td></tr></tbody></table>

In general, macrocycles featuring a 2-(3,4-dimethoxyphenyl)ethyl (Table 6, entries 2, 3, 5, 7) or 2-(2-methoxyphenyl)ethyl side chain (Table 6, entry 8) led to higher *ee* values than those bearing an hydroxypropyl side arm (Table 6, entries 4, 6). Likewise, with regard to enantioselectivity, the D-galactose-based crown ethers are slightly more efficient than the D-glucose-based ones.

Other cyclopropane derivatives synthesised from α,β-unsaturated cyanosulfones containing substituted phenyl, naphthyl, pyridyl, furyl and thienyl groups were obtained in good yields and enantioselectivities up to 85%.

### Epoxidation of enones

A large number of sugar-based crown ethers were tested for their efficacy in the asymmetric epoxidation of enones. These included methyl α-D-glucopyranosides whose positions 4 and 6 were either protected by a benzylidene (690) [282,289,317], isopropylidene (691) and (1-naphthyl)methylene group (692) or free (696) [293], the phenyl 4,6-O-benzylidene-β-D-glucopyranoside 703, two 4,6-O-benzylidene-α-D-galactopyranosides (713, 714) [282,302], several 4,6-O-benzylidene-β-D-galactopyranosides (715–720) [302], the methyl 4,6-O-benzylidene-α-D-altropyranoside 721g [304] and the methyl 4,6-O-benzylidene-α-D-mannopyranosides 722 [305,317].

The influence of the chain linked to the nitrogen atom of the carbohydrate-based lariat ethers on the performance of these catalysts was also studied. It appeared that the most efficient catalysts for the epoxidation of *trans*-chalcone 602 using *tert*-butylhydroperoxide were those with a hydroxypropyl side arm (Scheme 190). All the macrocycles featuring a D-glucose unit (690, 691, 692, 696 and 703) led mainly to the (2R,3S)-configurated enantiomer except 690a, which provided the (2S,3R)-epoxide with an enantiomeric excess of 28%.
<figure><img src="image_241.png" /><figcaption>**Scheme 190.** The epoxidation of chalcone catalysed by sugar-based aza-crown ethers functionalised with hydroxypropyl side arm.</figcaption></figure>

This enantiomer was also obtained as major product in the presence of the D-mannose-based catalysts **722g**, while the D-altrose-based crown ether **721g** gave no asymmetric induction (ee = 3%). In order to provide an explanation to these results, a theoretical study using molecular modeling and density functional theory (DFT) calculations was performed [304].

The aza-crown ethers **729** and **730**, containing a pyridine ring, were also used as phase transfer catalysts for this reaction [308]. The chiral macrocycles incorporating a glucopyranoside unit **729a-c** promoted the formation of the (2R,3S)-epoxide **609** with modest enantioselectivities (ee = 25–54%) and yields (36–40%), whereas the use of the mannopyranoside-based crown ether **730** gave rise to the opposite enantiomer in 39% yield and 47% enantiomeric excess.

### Darzens condensation

The Darzens condensation is another well-known method for the synthesis of epoxy ketones. Bakó and co-workers conducted this reaction starting from 2-chloroacetophenone (608) and benzaldehyde under liquid-liquid reaction conditions in the presence of a large number of aldose-based aza-crown ethers (Scheme 191) [286,289,293,298,299,302,305,313]. In all cases, the trans-epoxide **609** was formed with complete diastereoselectivity, whereas the best enantioselectivity (ee = 74%) was obtained using the lariat ether anellated to the 4,6-O-benzylidene-β-D-glucopyranoside **703g** at room temperature [298,299].

<figure><img src="image_242.png" /><figcaption>**Scheme 191.** Darzens condensation catalysed by aldose-based aza-crown ethers.</figcaption></figure>

In order to improve the enantioselectivity, other reactions were performed at lower temperature employing the catalysts based on methyl 4,6-O-benzylidene-α-D- glucopyranoside **690f** and **690g** [286,313]. Thus, when **690f** was the catalyst, the enantiomeric excess increased from 42% at 22 °C to 59% at –10 °C and 64% at –20 °C in favor of the (2R,3S)-isomer. As in the case of the epoxidation reaction (see Epoxidation of enones in Section 8.3.3.2), the opposite enantiomer was enantioselectively obtained in the presence of **722g** [305]. The same team extended the application of their organocatalysts to other aromatic or heteroaromatic α-chloroacetyl derivatives [318–320].

## 9. Conclusions

The chemical and stereochemical behaviours of hundreds of carbohydrate-based organocatalysts, including a few unmodified monosaccharides and oligosaccharides, have been studied over the last three decades. In particular, the interest of researchers has been centred on the synthesis and application of sugar thioureas, sugar ketones and sugar-based (aza)crown-ethers. Most organocatalysts have been employed to perform classical organic transformations, such as aldol reaction, the Mannich reaction and Diels–Alder cycloaddition.
Although these old reactions are still very useful and can benefit from chiral organocatalysts, it is fair to state that almost all the enantioselective reactions outlined in the present review were performed using extremely simple substrates. Moreover, in the vast majority of cases, the catalyst loading was rather high (10–20 mol%) and the reaction solvents were chosen exclusively on the basis of the chemical and stereochemical optimization of the catalysed reaction—the “green” characteristics of the solvent not being taken into consideration.

It can be also mentioned that the recycling of these quite complex catalysts was not always described in the published articles. Therefore, despite the huge effort required for their synthesis, the actual potential of highly functionalized sugar-based organocatalysts remains largely unexplored. In our opinion, it may be interesting to also exploit these catalysts in the diastereoselective preparation of complex compounds from simpler chiral substrates, including carbohydrates, aminoacids and other natural molecules.

**Funding:** This research was funded by the National Science Center (NCN) Poland, grant number 2018/30/M/ST5/00401.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

## References and Notes

1. Sharpless, K.B. Searching for New Reactivity (Nobel Lecture). *Angew. Chem. Int. Ed.* **2002**, *41*, 2024–2032. [CrossRef]

2. Van der Helm, M.P.; Klemm, B.; Eelkema, R. Organocatalysis in aqueous media. *Nat. Rev. Chem.* **2019**, *3*, 491–508. [CrossRef]

3. Xiang, S.-H.; Tan, B. Advances in asymmetric organocatalysis over the last 10 years. *Nat. Commun.* **2020**, *11*, 3786. [CrossRef] [PubMed]

4. Han, B.; He, X.-H.; Liu, Y.-Q.; He, G.; Peng, C.; Li, J.-L. Asymmetric organocatalysis: An enabling technology for medicinal chemistry. *Chem. Soc. Rev.* **2021**, *50*, 1522–1586. [CrossRef]

5. Jarosz, S.; Listkowski, A. Sugar Derived Crown Ethers and Their Analogs: Synthesis and Properties. *Curr. Org. Chem.* **2006**, *10*, 643–662. [CrossRef]

6. Bakó, P.; Keglevich, G.; Rapi, Z. Asymmetric Phase Transfer Reactions Catalyzed by Chiral Crown Ethers Derived from Monosaccharides. *Lett. Org. Chem.* **2010**, *7*, 645–656. [CrossRef]

7. Bakó, P.; Rapi, Z.; Keglevich, G. Sugar-based Crown Ethers in Enantioselective Syntheses. *Period. Polytech. Chem. Eng.* **2015**, *59*, 51–58. [CrossRef]

8. Schettini, R.; Sicignano, M.; De Riccardis, F.; Izzo, I.; Sala, G.D. Macrocyclic Hosts in Asymmetric Phase-Transfer Catalyzed Reactions. *Synthesis* **2018**, *50*, 4777–4795.

9. Frohn, M.; Shi, Y. Chiral Ketone-Catalyzed Asymmetric Epoxidation of Olefins. *Synthesis* **2000**, *2000*, 1979–2000. [CrossRef]

10. Wong, O.A.; Shi, Y. Organocatalytic oxidation. Asymmetric epoxidation of olefins catalyzed by chiral ketones and iminium salts. *Chem. Rev.* **2008**, *108*, 3958–3987. [CrossRef]

11. Shi, Y. Organocatalytic asymmetric epoxidation of olefins by chiral ketones. *Acc. Chem. Res.* **2004**, *37*, 488–496. [CrossRef]

12. Yang, D. Ketone-Catalyzed Asymmetric Epoxidation Reactions. *Acc. Chem. Res.* **2004**, *37*, 497–505. [CrossRef]

13. Zhu, Y.; Wang, Q.; Cornwall, R.G.; Shi, Y. Organocatalytic asymmetric epoxidation and aziridination of olefins and their synthetic applications. *Chem. Rev.* **2014**, *114*, 8199–8256. [CrossRef]

14. Boysen, M.M.K. Carbohydrates as synthetic tools in organic chemistry. *Chem. A Eur. J.* **2007**, *13*, 8648–8659. [CrossRef]

15. Lehnert, T.; Özüduru, G.; Grugel, H.; Albrecht, F.; Telligmann, S.M.; Boysen, M.M.K. More than just sweet—Sugar-derived stereodifferentiating agents for asymmetric synthesis. *Synthesis* **2011**, *2011*, 2685–2708.

16. Ma, J.A.; Zhang, G.-W. Enantioselective Addition Reactions Catalyzed by Carbohydrate-Derived Organocatalysts. In *Carbohydrates—Tools for Stereoselective Synthesis*, 1st ed.; Boysen, M.M.K., Ed.; Wiley-VCH: Weinheim, Germany, 2013; pp. 351–370.

17. Phillips, A.M.F. Applications of Carbohydrate-Based Organocatalysts in Enantioselective Synthesis. *Eur. J. Org. Chem.* **2014**, *2014*, 7291–7303. [CrossRef]

18. Henderson, A.S.; Bower, J.F.; Galan, M.C. Carbohydrates as enantioinduction components in stereoselective catalysis. *Org. Biomol. Chem.* **2016**, *14*, 4008–4017. [CrossRef]

19. Agarwal, J. Progress in aminosugar derived asymmetric organocatalysis. *Org. Biomol. Chem.* **2016**, *14*, 10747–10762. [CrossRef]

20. Mondal, M.A.; Mandal, D. Carbohydrate-based organocatalysts in direct asymmetric aqueous aldol reaction. *J. Carbohydr. Chem.* **2016**, *35*, 181–200. [CrossRef]

21. Ikai, T. The dawn of chiral material development using saccharide-based helical polymers. *Polym. J.* **2017**, *49*, 355–362. [CrossRef]

22. Mahé, O.; Brière, J.-F.; Dez, I. Chitosan: An Upgraded Polysaccharide Waste for Organocatalysis. *Eur. J. Org. Chem.* **2015**, *2015*, 2559–2578. [CrossRef]
23. El Kadib, A. Chitosan as a Sustainable Organocatalyst: A Concise Overview. *ChemSusChem* **2015**, *8*, 217–244. [CrossRef]

24. Pan, D.; Ganguly, J. Assessment of Chitosan Based Catalyst and Their Mode of Action. *Curr. Organocatal.* **2019**, *6*, 106–138. [CrossRef]

25. Meninno, S. Valorization of Waste: Sustainable Organocatalysts from Renewable Resources. *ChemSusChem* **2020**, *13*, 439–468. [CrossRef]

26. Sigman, M.S.; Jacobsen, E.N. Schiff base catalysts for the asymmetric Strecker reaction identified and optimized from parallel synthetic libraries. *J. Am. Chem. Soc.* **1998**, *120*, 4901–4902. [CrossRef]

27. Sigman, M.S.; Vachal, P.; Jacobsen, E.N. A general catalyst for the asymmetric Strecker reaction. *Angew. Chem. Int. Ed.* **2000**, *39*, 1279–1281. [CrossRef]

28. Okino, T.; Nakamura, S.; Furukawa, T.; Takemoto, Y. Enantioselective aza-Henry reaction catalyzed by a bifunctional organocatalyst. *Org. Lett.* **2004**, *6*, 625–627. [CrossRef]

29. Sohtome, Y.; Tanatani, A.; Hashimoto, Y.; Nagasawa, K. Development of bis-thiourea-type organocatalyst for asymmetric Baylis–Hillman reaction. *Tetrahedron Lett.* **2004**, *45*, 5589–5592. [CrossRef]

30. Liu, K.; Cui, H.-F.; Nie, J.; Dong, K.-Y.; Li, X.-J.; Ma, J.-A. Highly Enantioselective Michael Addition of Aromatic Ketones to Nitroolefins Promoted by Chiral Bifunctional Primary Amine-thiourea Catalysts Based on Saccharides. *Org. Lett.* **2007**, *9*, 923–925. [CrossRef]

31. Timmons, S.C.; Jakeman, D.L. Stereoselective Chemical Synthesis of Sugar Nucleotides via Direct Displacement of Acylated Glycosyl Bromides. *Org. Lett.* **2007**, *9*, 1227–1230. [CrossRef]

32. Zhang, S.; Moussodia, R.-O.; Sun, H.-J.; Leowanawat, P.; Muncan, A.; Nusbaum, C.D.; Chelling, K.M.; Heiney, P.A.; Klein, M.L.; André, S.; et al. Mimicking Biological Membranes with Programmable Glycan Ligands Self-Assembled from Amphiphilic Janus Glycodendrimers. *Angew. Chem. Int. Ed.* **2014**, *53*, 10899–10903. [CrossRef] [PubMed]

33. Nagy, S.; Kozma, P.; Kisszékelyi, P.; Bezzegh, D.; Huszthy, P.; Kupai, J. Synthesis of Three New Bifunctional Glucose-Thiourea Organocatalysts and Their Application in Asymmetric Michael Addition. *Studia Ubb. Chem.* **2017**, *62*, 183–194. [CrossRef]

34. Pearson, M.S.M.; Robin, A.; Bourgougnon, N.; Meslin, J.C.; Deniaud, D. An Efficient Route to Pyrimidine Nucleoside Analogues by [4 + 2] Cycloaddition Reaction. *J. Org. Chem.* **2003**, *68*, 8583–8587. [CrossRef] [PubMed]

35. Camarasa, M.J.; Fernández-Resa, P.; García-López, M.T.; de las Heras, F.G.; Méndez-Castrillón, P.P.; Felix, A.S. A New Procedure for the Synthesis of Glycosyl Isothiocyanates. *Synthesis* **1984**, *6*, 509–510. [CrossRef]

36. Lindhorst, T.K.; Kieburg, C. Solvent-Free Preparation of Glycosyl Isothiocyanates. *Synthesis* **1995**, *1995*, 1228–1230. [CrossRef]

37. Gu, X.-T.; Guo, Q.; Wu, X.-Y. Highly enantioselective Michael addition of acetone to nitroolefins catalyzed by chiral bifunctional primary amine-thiourea catalysts with acetic acid. *Tetrahedron* **2009**, *65*, 5265–5270. [CrossRef]

38. Li, X.-J.; Liu, K.; Ma, H.; Nie, J.; Ma, J.-A. Highly Enantioselective Michael Addition of Malonates to Nitroolefins Catalyzed by Chiral Bifunctional Tertiary Amine-Thioureas Based on Saccharides. *Synlett* **2008**, *2008*, 3242–3246. [CrossRef]

39. Gao, P.; Wang, C.; Wu, Y.; Zhou, Z.; Tang, C. Sugar-Derived Bifunctional Thiourea Organocatalyzed Asymmetric Michael Addition of Acetylacetone to Nitroolefins. *Eur. J. Org. Chem.* **2008**, *2008*, 4563–4566. [CrossRef]

40. Lu, A.; Gao, P.; Wu, Y.; Wang, Y.; Zhou, Z.; Tang, C. Highly enantio- and diastereoselective Michael addition of cyclohexanone to nitroolefins catalyzed by a chiral glucose-based bifunctional secondary amine-thiourea catalyst. *Org. Biomol. Chem.* **2009**, *7*, 3141–3147. [CrossRef]

41. Ma, H.; Liu, K.; Zhang, F.-G.; Zhu, C.-L.; Nie, J.; Ma, J.-A. Chiral bifunctional thiourea-catalyzed enantioselective Michael addition of ketones to nitrodienes. *J. Org. Chem.* **2010**, *75*, 1402–1409. [CrossRef]

42. Pu, X.; Li, P.; Peng, F.; Li, X.; Zhang, H.; Shao, Z. Asymmetric Conjugate Addition of Acetylacetone to Nitroolefins with Chiral Organocatalysts Derived from Both α-Amino-Acids and Carbohydrates. *Eur. J. Org. Chem.* **2009**, *2009*, 4622–4626. [CrossRef]

43. Pu, X.-W.; Peng, F.-Z.; Zhang, H.-B.; Shao, Z.-H. Doubly stereocontrolled asymmetric conjugate addition of acetylacetone to nitroolefins catalyzed by bifunctional tertiary amine-thiourea catalysts derived from both acyclic α-amino acids and carbohydrates. *Tetrahedron* **2010**, *66*, 3655–3661. [CrossRef]

44. Reddy, B.V.S.; Reddy, S.M.; Swain, M.; Dudem, S.; Kalivendi, S.V.; Reddy, C.S. Enantioselective 1,4-addition of kojic acid derivatives to β-nitroolefins catalyzed by a cinchonine derived sugar thiourea. *RSC Adv.* **2014**, *4*, 9107–9111. [CrossRef]

45. Puglisi, A.; Benaglia, M.; Raimondi, L.; Lay, L.; Poletti, L. Novel carbohydrate-based bifunctional organocatalysts for nucleophilic addition to nitroolefins and imines. *Org. Biomol. Chem.* **2011**, *9*, 3295–3302. [CrossRef]

46. Ágoston, K.; Fügedi, P. Preparation of new type of organocatalysts having a carbohydrate scaffold. *Carbohydr. Res.* **2014**, *389*, 50–56. [CrossRef]

47. Fuller, T.S.; Stick, R.V. Further Stereoselective Reductions of 3-O-Hexofuranosyl S-Methyl Dithiocarbonates with Tributyltin Deuteride. A Comment on Mechanism. *Austr. J. Chem.* **1980**, *33*, 2509–2515. [CrossRef]

48. Azad, C.S.; Khan, I.A.; Narula, A.K. Organocatalyzed asymmetric Michael addition by an efficient bifunctional carbohydrate-thiourea hybrid with mechanistic DFT analysis. *Org. Biomol. Chem.* **2016**, *14*, 11454–11461. [CrossRef]

49. Rončák, R.; Tvrdónová, M.; Gonda, J.; Elečko, J. Novel carbohydrate-based thioureas as organocatalysts for asymmetric Michael addition of 1,3-dicarbonyl compounds to nitroolefins. *Tetrahedron* **2020**, *76*, 131339. [CrossRef]

50. Gonda, J.; Martinková, M.; Raschmanová, J.; Balentová, E. Creation of quaternary stereocentres via [3,3]-sigmatropic rearrangement of allylic thiocyanates. A synthetic approach to (+)-myriocin. *Tetrahedron Asymmetry* **2006**, *17*, 1875–1882. [CrossRef]
51. Tronchet, J.M.J.; Gentile, B. 3-C-(Acylméthylène)-3-désoxy-1,2,5,6-di-O-isopropylidène-α-D-ribo- et -xylo-hexofuranoses. *Carbohydr. Res.* **1975**, *44*, 23–35. [CrossRef]

52. Tadano, K.; Idogaki, Y.; Yamada, H.; Suami, T. Introduction of gem-dialkyl group to hexofuranose by ortho ester Claisen rearrangement. *Chem. Lett.* **1985**, *14*, 1925–1928. [CrossRef]

53. Tadano, K.; Idogaki, Y.; Yamada, H.; Suami, T. Ortho Ester Claisen Rearrangements of Three 3-C-(Hydroxymethyl)methylene Derivatives of Hexofuranose: Stereoselective Introduction of a Quaternary Center on C-3 of D-ribo-, L-lyxo-, and D-arabino-Hexofuranoses. *J. Org. Chem.* **1987**, *52*, 1201–1210. [CrossRef]

54. Li, F.; Sun, L.; Teng, Y.; Yu, P.; Zhao, J.C.-G.; Ma, J.-A. Highly Diastereo- and Enantioselective Organocatalytic One-Pot Sequential 1,4-Addition/Dearomative-Fluorination Transformation. *Chem. Eur. J.* **2012**, *18*, 14255–14260. [CrossRef]

55. Meng, W.-T.; Zheng, Y.; Nie, J.; Xiong, H.-Y.; Ma, J.-A. Organocatalytic Asymmetric One-Pot Sequential Conjugate Addition/Dearomative Fluorination: Synthesis of Chiral Fluorinated Isoxazol-5(4H)-ones. *J. Org. Chem.* **2013**, *78*, 559–567. [CrossRef]

56. Zheng, W.; Zhang, J.; Liu, S.; Yu, C.; Miao, Z. Asymmetric synthesis of spiro[chroman-3,3'-pyrazol] scaffolds with an all-carbon quaternary stereocenter via a oxa-Michael–Michael cascade strategy with bifunctional amine-thiourea organocatalysts. *RSC Adv.* **2015**, *5*, 91108–91113. [CrossRef]

57. Nie, J.; Li, X.-J.; Zheng, D.-H.; Zhang, F.-G.; Cui, S.; Ma, J.-A. Chiral bifunctional thiourea-catalyzed enantioselective aldol reaction of trifluoroacetaldehyde hemiacetal with aromatic ketones. *J. Fluor. Chem.* **2011**, *132*, 468–473. [CrossRef]

58. Yuan, H.-N.; Wang, S.; Nie, J.; Meng, W.; Yao, Q.; Ma, J.-A. Hydrogen-Bond-Directed Enantioselective Decarboxylative Mannich Reaction of β-Ketoacids with Ketimines: Application to the Synthesis of Anti-HIV Drug DPC 083. *Angew. Chem. Int. Ed.* **2013**, *52*, 3869–3873. [CrossRef]

59. Yuan, H.-N.; Li, S.; Nie, J.; Zheng, Y.; Ma, J.-A. Highly Enantioselective Decarboxylative Mannich Reaction of Malonic Acid Half Oxyesters with Cyclic Trifluoromethyl Ketimines: Synthesis of β-Amino Esters and Anti-HIV Drug DPC 083. *Chem. Eur. J.* **2013**, *19*, 15856–15860. [CrossRef]

60. Qiao, B.; Huang, Y.-J.; Nie, J.; Ma, J.-A. Highly Regio-, Diastereo-, and Enantioselective Mannich Reaction of Allylic Ketones and Cyclic Ketimines: Access to Chiral Benzosultam. *Org. Lett.* **2015**, *17*, 4608–4611. [CrossRef]

61. Liu, Y.-J.; Li, J.-S.; Nie, J.; Ma, J.-A. Organocatalytic Asymmetric Decarboxylative Mannich Reaction of β-Keto Acids with Cyclic α-Ketiminophosphonates: Access to Quaternary α-Aminophosphonates. *Org. Lett.* **2018**, *20*, 3643–3646. [CrossRef]

62. Wang, C.; Zhou, Z.; Tang, C. Novel Bifunctional Chiral Thiourea Catalyzed Highly Enantioselective aza-Henry Reaction. *Org. Lett.* **2008**, *10*, 1707–1710. [CrossRef]

63. Robak, J.; Kryczka, B.; Świerczyńska, B.; Zawisza, A.; Porwański, S. New sugar-derived bifunctional chiral ureas as highly effective organocatalysts in asymmetric aza-Henry reaction. *Carbohydr. Res.* **2015**, *404*, 83–86. [CrossRef] [PubMed]

64. Deras, I.L.; Takegawa, K.; Kondo, A.; Kato, I.; Lee, Y.C. Synthesis of a high-mannose-type glycopeptide analog containing a glucose-asparagine linkage. *Bioorg. Med. Chem. Lett.* **1998**, *8*, 1763–1766. [CrossRef]

65. Szarek, W.A.; Jones, J.K.N. Carbohydrate containing nitrogen in a five-membered ring and an attempted synthesis of a carbohydrate with nitrogen in a seven-membered ring. *Can. J. Chem.* **1965**, *43*, 2345–2356. [CrossRef]

66. Pető, C.; Batta, G.; Györgydeák, Z.; Sztaricskai, F. Zur Darstellung der Anomeren des Hepta-O-acetylcellobiosyl-, -lactosyl-, -maltosyl- und -melibiosylazids. *Liebigs Ann. Chem.* **1991**, *1991*, 505–507. [CrossRef]

67. Yang, W.; Sha, F.; Zhang, X.; Yuan, K.; Wu, X. Enantioselective Morita-Baylis-Hillman Reaction Organocatalyzed by Glucose-based Phosphinothiourea. *Chin. J. Chem.* **2012**, *30*, 2652–2656. [CrossRef]

68. Porwański, S. New ureas containing glycosyl and diphenylphosphinyl scaffolds: Synthesis and the first attempts to use them in asymmetric synthesis. *Carbohydr. Res.* **2014**, *394*, 7–12. [CrossRef]

69. Wang, Y.; Yang, H.; Yu, J.; Miao, Z.; Chen, R. Highly Enantioselective Biginelli Reaction Promoted by Chiral Bifunctional Primary Amine-Thiourea Catalysts: Asymmetric Synthesis of Dihydropyrimidines. *Adv. Synth. Catal.* **2009**, *351*, 3057–3062. [CrossRef]

70. Kong, S.; Fan, W.; Wu, G.; Miao, Z. Enantioselective Synthesis of Tertiary α-Hydroxy Phosphonates Catalyzed by Carbohydrate/Cinchona Alkaloid Thiourea Organocatalysts. *Angew. Chem. Int. Ed.* **2012**, *51*, 8864–8867. [CrossRef]

71. Tu, Y.; Wang, Z.X.; Shi, Y. An efficient asymmetric epoxidation method for trans-olefins mediated by a fructose-derived ketone. *J. Am. Chem. Soc.* **1996**, *118*, 9806–9807. [CrossRef]

72. Mio, S.; Kumagawa, Y.; Sugai, S. Synthetic studies on (+)-hydantocidin (3): A new synthetic method for construction of the spiro-hydantoin ring at the anomeric position of D-ribofuranose. *Tetrahedron* **1991**, *47*, 2133–2144. [CrossRef]

73. Wang, Z.X.; Tu, Y.; Frohn, M.; Shi, Y. A Dramatic pH Effect Leads to a Catalytic Asymmetric Epoxidation. *J. Org. Chem.* **1997**, *62*, 2328–2329. [CrossRef]

74. Wang, Z.X.; Tu, Y.; Frohn, M.; Zhang, J.R.; Shi, Y. An efficient catalytic asymmetric epoxidation method. *J. Am. Chem. Soc.* **1997**, *119*, 11224–11235. [CrossRef]

75. Chen, C.C.; Whistler, R.L. Synthesis of L-fructose. *Carbohydr. Res.* **1988**, *175*, 265–271. [CrossRef]

76. Wang, Z.X.; Shi, Y. A pH Study on the Chiral Ketone Catalyzed Asymmetric Epoxidation of Hydroxyalkenes. *J. Org. Chem.* **1998**, *63*, 3099–3104. [CrossRef]

77. Cao, G.A.; Wang, Z.X.; Tu, Y.; Shi, Y. Chemo- and enantioselective epoxidation of enynes. *Tetrahedron Lett.* **1998**, *39*, 4425–4428. [CrossRef]

78. Wang, Z.X.; Cao, G.A.; Shi, Y. Chiral ketone catalyzed highly chemo- and enantioselective epoxidation of conjugated enynes. *J. Org. Chem.* **1999**, *64*, 7646–7650. [CrossRef]
79. Zhu, Y.; Tu, Y.; Yu, H.; Shi, Y. Highly enantioselective epoxidation of enol silyl ethers and esters. *Tetrahedron Lett.* **1998**, *39*, 7819–7822. [CrossRef]

80. Zhu, Y.; Shu, L.; Tu, Y.; Shi, Y. Enantioselective synthesis and stereoselective rearrangements of enol ester epoxides. *J. Org. Chem.* **2001**, *66*, 1818–1826. [CrossRef]

81. Warren, J.D.; Shi, Y. Chiral ketone-catalyzed asymmetric epoxidation of 2,2-disubstituted vinylsilanes. *J. Org. Chem.* **1999**, *64*, 7675–7677. [CrossRef]

82. Frohn, M.; Zhou, X.; Zhang, J.R.; Tang, Y.; Shi, Y. Kinetic resolution of racemic cyclic olefins via chiral dioxirane. *J. Am. Chem. Soc.* **1999**, *121*, 7718–7719. [CrossRef]

83. Shu, L.; Shi, Y. Asymmetric epoxidation using hydrogen peroxide (H₂O₂) as primary oxidant. *Tetrahedron Lett.* **1999**, *40*, 8721–8724. [CrossRef]

84. Shu, L.; Shi, Y. An efficient ketone-catalyzed asymmetric epoxidation using hydrogen peroxide (H₂O₂) as primary oxidant. *Tetrahedron* **2001**, *57*, 5213–5218. [CrossRef]

85. Tu, Y.; Wang, Z.X.; Frohn, M.; He, M.; Yu, H.; Tang, Y.; Shi, Y. Structural probing of ketone catalysts for asymmetric epoxidation. *J. Org. Chem.* **1998**, *63*, 8475–8485. [CrossRef]

86. Fernández, J.M.G.; Mellet, C.O.; Marín, A.M.; Fuentes, J. A mild and efficient procedure to remove acetal and dithioacetal protecting groups in carbohydrate derivatives using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. *Carbohydr. Res.* **1995**, *274*, 263–268. [CrossRef]

87. Differding, E.; Ofner, H. N-Fluorobenzenesulfonimide: A Practical Reagent for Electrophilic Fluorinations. *Synlett* **1991**, 1991, 187–189. [CrossRef]

88. Kang, J.; Lim, G.J.; Yoon, S.K.; Kim, M.Y. Asymmetric Cyclopropanation Using New Chiral Auxiliaries Derived from D-Fructose. *J. Org. Chem.* **1995**, *60*, 564–577. [CrossRef]

89. Garegg, P.J.; Samuelsson, B. One-step conversion of vicinal diols into olefins, using a novel reagent system. *Synthesis* **1979**, 1979, 469–470. [CrossRef]

90. Lichtenthaler, F.W.; Doleschal, W.; Hahn, S. Spirocyclic Dihydropyranones from D-Fructose. *Liebigs Ann. Chem.* **1985**, 1985, 2454–2464. [CrossRef]

91. Matsumoto, K.; Ebata, T.; Matsushita, H. Novel synthesis of 3-acetamido-3-deoxy- and 4-acetamido-4-deoxy-D-altrose from levoglucosenone using regioselective cis-oxyamination. *Carbohydr. Res.* **1995**, *267*, 187–201. [CrossRef]

92. Rubin, A.E.; Sharpless, K.B. A Highly Efficient Aminohydroxylation Process. *Angew. Chem. Int. Ed. Engl.* **1997**, *36*, 2637–2640. [CrossRef]

93. Tian, H.; She, X.; Shi, Y. Electronic probing of ketone catalysts for asymmetric epoxidation. Search for more robust catalysts. *Org. Lett.* **2001**, *3*, 715–718. [CrossRef]

94. Chan, J.Y.C.; Cheong, P.P.L.; Hough, L.; Richardson, A.C. The preparation and reactions of a new glycoside: 2'-Chloroethyl β-D-fructopyranoside. *J. Chem. Soc. Perkin Trans.* **1985**, *4*, 1447–1455. [CrossRef]

95. Aamlid, K.H.; Hough, L.; Richardson, A.C.; Hendry, D. An enantiospecific synthesis of (R)-1,4,7-trioxaspiro[5.5]undecane from D-fructose. *Carbohydr. Res.* **1987**, *164*, 373–390. [CrossRef]

96. Bennett, M.; Gill, G.B.; Pattenden, G.; Shuker, A.J.; Stapleton, A. Ylidenebutenolide mycotoxins. Concise syntheses of patulin and neopatulin from carbohydrate precursors. *J. Chem. Soc. Perkin Trans.* **1991**, *1991*, 929–937. [CrossRef]

97. Zottola, M.A.; Alonso, R.; Vite, G.D.; Fraser-Reid, B. A Practical, Efficient Large-Scale Synthesis of 1,6-Anhydrohexopyranoses. *J. Org. Chem.* **1989**, *54*, 6123–6125. [CrossRef]

98. Tian, H.; She, X.; Shu, L.; Yu, H.; Shi, Y. Highly enantioselective epoxidation of cis-olefins by chiral dioxirane. *J. Am. Chem. Soc.* **2000**, *122*, 11551–11552. [CrossRef]

99. Tian, H.; She, X.; Xu, J.; Shi, Y. Enantioselective epoxidation of terminal olefins by chiral dioxirane. *Org. Lett.* **2001**, *3*, 1929–1931. [CrossRef]

100. Tian, H.; She, X.; Yu, H.; Shu, L.; Shi, Y. Designing new chiral ketone catalysts. Asymmetric epoxidation of cis-olefins and terminal olefins. *J. Org. Chem.* **2002**, *67*, 2435–2446. [CrossRef]

101. Shu, L.; Shen, Y.M.; Burke, C.; Goeddel, D.; Shi, Y. An improved synthesis of a ketone catalyst for asymmetric epoxidation of olefins. *J. Org. Chem.* **2003**, *68*, 4963–4965. [CrossRef]

102. Corey, E.J.; Hopkins, B. A mild procedure for the conversion of 1,2-diols to olefins. *Tetrahedron Lett.* **1982**, *23*, 1979–1982. [CrossRef]

103. Shu, L.; Wang, P.; Gan, Y.; Shi, Y. Asymmetric epoxidation catalyzed by N-aryl-substituted oxazolidinone-containing ketones: Further evidence for electronic effects. *Org. Lett.* **2003**, *5*, 293–296. [CrossRef] [PubMed]

104. Goeddel, D.; Shu, L.; Yuan, Y.; Wong, O.A.; Wang, B.; Shi, Y. Effective asymmetric epoxidation of styrenes by chiral dioxirane. *J. Org. Chem.* **2006**, *71*, 1715–1717. [CrossRef] [PubMed]

105. Zhao, M.X.; Goeddel, D.; Li, K.; Shi, Y. A practical synthesis of N-aryl-substituted oxazolidinone-containing ketone catalysts for asymmetric epoxidation. *Tetrahedron* **2006**, *62*, 8064–8068. [CrossRef]

106. Shu, L.; Shi, Y. Asymmetric epoxidation of cis-β-methylstyrenes catalyzed by N-aryl substituted oxazolidinone-containing ketones. A beneficial substituent effect. *Tetrahedron Lett.* **2004**, *45*, 8115–8117. [CrossRef]

107. Burke, C.P.; Shi, Y. Enantioselective epoxidation of nonconjugated cis-olefins by chiral dioxirane. *Org. Lett.* **2009**, *11*, 5150–5153. [CrossRef]

108. He, J.; Ling, J.; Chiu, P. Vinyl epoxides in organic synthesis. *Chem. Rev.* **2014**, *114*, 8037–8128. [CrossRef]
109. Marshall, J.A. SN2' Additions of organocopper reagents to vinyloxiranes. *Chem. Rev.* **1989**, *89*, 1503–1511. [CrossRef]

110. Burke, C.P.; Shi, Y. Regio- and Enantioselective Epoxidation of Dienes by a Chiral Dioxirane: Synthesis of Optically Active Vinylcis-Epoxides. *Angew. Chem. Int. Ed.* **2006**, *45*, 4475–4478. [CrossRef]

111. Burke, C.P.; Shi, Y. Enantioselective epoxidation of conjugated cis-enynes by chiral dioxirane. *J. Org. Chem.* **2007**, *72*, 4093–4097. [CrossRef]

112. Shen, Y.M.; Wang, B.; Shi, Y. Enantioselective synthesis of 2-alkyl-2-aryl cyclopentanones by asymmetric epoxidation of tetrasubstituted cyclobutylidene olefins and epoxide rearrangement. *Tetrahedron Lett.* **2006**, *47*, 5455–5458. [CrossRef]

113. Wang, B.; Wong, O.A.; Zhao, M.X.; Shi, Y. Asymmetric epoxidation of 1,1-disubstituted terminal olefins by chiral dioxirane via a planar-like transition state. *J. Org. Chem.* **2008**, *73*, 9539–9543. [CrossRef]

114. Wu, X.Y.; She, X.; Shi, Y. Highly enantioselective epoxidation of α,β-unsaturated esters by chiral dioxirane. *J. Am. Chem. Soc.* **2002**, *124*, 8792–8793. [CrossRef]

115. Wang, B.; Wu, X.Y.; Wong, O.A.; Nettles, B.; Zhao, M.X.; Chen, D.; Shi, Y. A diacetate ketone-catalyzed asymmetric epoxidation of olefins. *J. Org. Chem.* **2009**, *74*, 3986–3989. [CrossRef]

116. Shing, T.K.M.; Leung, G.Y.C. Asymmetric epoxidation catalyzed by D-glucose-derived uloses. *Tetrahedron* **2002**, *58*, 7545–7552. [CrossRef]

117. Shing, T.K.M.; Leung, G.Y.C.; Yeung, K.W. Catalytic enantioselective epoxidation with arabinose-derived uloses containing tunable steric sensors. *Tetrahedron Lett.* **2003**, *44*, 9225–9228. [CrossRef]

118. Shing, T.K.M.; Leung, Y.C.; Yeung, K.W. Catalytic asymmetric epoxidation of alkenes with arabinose-derived uloses. *Tetrahedron* **2003**, *59*, 2159–2168. [CrossRef]

119. Shing, T.K.M.; Leung, G.Y.C.; Luk, T. Arabinose-derived ketones as catalysts for asymmetric epoxidation of alkenes. *J. Org. Chem.* **2005**, *70*, 7279–7289. [CrossRef]

120. Shing, T.K.M.; Fung, W.-C.; Wong, C.-H. Ring-selective Syntheses of Homochiral Oxepanes and Tetrahydropyrans from Carbohydrates via Intramolecular Nitrone or Nitrile Oxide Cycloadditions. *J. Chem. Soc. Chem. Commun.* **1994**, 449–450. [CrossRef]

121. Zhong, Y.-L.; Shing, T.K.M. Efficient and Facile Glycol Cleavage Oxidation Using Improved Silica Gel-Supported Sodium Metaperiodate. *J. Org. Chem.* **1997**, *62*, 2622–2624. [CrossRef]

122. Baker, D.C.; Horton, D.; Tindall, C.G. Large-scale preparation of D-allose: Observations on the stereoselectivity of the reduction of 1,2,5,6-di-O-isopropylidene-α-D-ribo-hexofuranos-3-ulose hydrate. *Carbohydr. Res.* **1972**, *24*, 192–197. [CrossRef]

123. Shing, T.K.M.; Luk, T.; Lee, C.M. Asymmetric epoxidation of cis-alkenes with arabinose-derived ketones: Enantioselective synthesis of the side chain of Taxol. *Tetrahedron* **2006**, *62*, 6621–6629. [CrossRef]

124. Shing, T.K.M.; Luk, T. Catalytic asymmetric epoxidation of alkenes with arabinose-derived ketones containing a cyclohexane-1,2-diacetal. *Tetrahedron Asymmetry* **2009**, *20*, 883–886. [CrossRef]

125. Vega-Pérez, J.M.; Candela, J.I.; Blanco, E.; Iglesias-Guerra, F. Stereoselective synthesis of epoxyalkyl glycoside precursors of glycosyl glycerol analogues from alkenyl glycosides of N-acetyl-D-glucosamine derivatives. *Tetrahedron Asymmetry* **2002**, *13*, 2471–2483. [CrossRef]

126. Vega-Pérez, J.M.; Vega, M.; Blanco, E.; Iglesias-Guerra, F. Stereoselective synthesis of oxiranes using oxazolidines derived from 2-amino-2-deoxy-D-allose as chiral auxiliaries. *Tetrahedron Asymmetry* **2001**, *12*, 3189–3203. [CrossRef]

127. Vega-Pérez, J.M.; Vega, M.; Blanco, E.; Iglesias-Guerra, F. Stereoselective epoxidation of alkenylidene acetals derived from carbohydrates with D-*allo*, D-*altro*, D-*galacto*, D-*gluco* and D-*xylo* configurations. *Tetrahedron Asymmetry* **2007**, *18*, 1850–1867. [CrossRef]

128. Vega-Pérez, J.M.; Holm, M.V.; Martínez, M.L.; Blanco, E.; Iglesias-Guerra, F. Synthesis of New Chiral Ketones from D-Glucose Derivatives and Their Use in the Enantioselective Epoxidation of Arylalkenes. *Eur. J. Org. Chem.* **2009**, 6009–6018. [CrossRef]

129. Vega-Pérez, J.M.; Vega-Holm, M.; Periñán, I.; Palo-Nieto, C.; Iglesias-Guerra, F. Synthesis of new carbohydrate-derived ketones as organocatalysts in the enantioselective epoxidation of arylalkenes. Part 2: Chiral ketones from sugars. *Tetrahedron* **2011**, *67*, 364–372. [CrossRef]

130. Vega-Pérez, J.M.; Periñán, I.; Palo-Nieto, C.; Vega-Holm, M.; Iglesias-Guerra, F. Alkenyl β-D-galactopyranoside derivatives as efficient chiral templates in stereoselective cyclopropanation and epoxidation reactions. *Tetrahedron Asymmetry* **2010**, *21*, 81–95. [CrossRef]

131. Vega-Pérez, J.M.; Periñán, I.; Vega-Holm, M.; Palo-Nieto, C.; Iglesias-Guerra, F. New mannose-derived ketones as organocatalysts for enantioselective dioxirane-mediated epoxidation of arylalkenes. Part 3: Chiral ketones from sugars. *Tetrahedron* **2011**, *67*, 7057–7065. [CrossRef]

132. Yang, D.; Yip, Y.; Tang, M.; Road, P.; Kong, H.; August, R.V. A C₂ Symmetric Chiral Ketone for Catalytic Asymmetric Epoxidation of Unfunctionalized Olefins. *J. Am. Chem. Soc.* **1996**, *118*, 491–492. [CrossRef]

133. Adam, W.; Zhao, C.G. Synthesis of optically active C₂-symmetric ketones for the asymmetric epoxidation of prochiral olefins by dioxiranes generated *in situ* with Caroate as a peroxide source. *Tetrahedron Asymmetry* **1997**, *8*, 3995–3998. [CrossRef]

134. Moberg, C. C₃ Symmetry in Asymmetric Catalysis and Chiral Recognition. *Angew. Chem. Int. Ed.* **1998**, *37*, 248–268. [CrossRef]

135. Baumstark, A.L.; McCloskey, C.J. Epoxidation of alkenes by dimethyldioxirane: Evidence for a spiro transition state. *Tetrahedron Lett.* **1987**, *28*, 3311–3314. [CrossRef]
136. Lee, E.; Mcardle, P.; Browne, P. N.m.r. (¹H and ¹³C) studies of some cis- and trans fused 4,6-*O*-benzylidene-hexopyranoside derivatives. *Carbohydr. Res.* **1990**, *197*, 262–269. [CrossRef]

137. Jalsa, N.K.; Singh, G. A unique approach to the synthesis of a dengue vaccine and the novel tetrasaccharide that results. *Tetrahedron Asymmetry* **2009**, *20*, 867–874. [CrossRef]

138. Boutureira, O.; McGouran, J.F.; Stafford, R.L.; Emmerson, D.P.G.; Davis, B.G. Accessible sugars as asymmetric olefin epoxidation organocatalysts: Glucosaminide ketones in the synthesis of terminal epoxides. *Org. Biomol. Chem.* **2009**, *7*, 4285–4288. [CrossRef]

139. Colonna, S.; Pironti, V.; Drabowicz, J.; Brebion, F.; Fensterbank, L.; Malacria, M. Enantioselective Synthesis of Thiosulfinates and of Acyclic Alkylidenemethylene Sulfide Sulfoxides. *Eur. J. Org. Chem.* **2005**, *2005*, 1727–1730. [CrossRef]

140. Khiar, N.; Mallouk, S.; Valdivia, V.; Bougrin, K.; Soufiaoui, M.; Fernández, I. Enantioselective organocatalytic oxidation of functionalized sterically hindered disulfides. *Org. Lett.* **2007**, *9*, 1255–1258. [CrossRef]

141. Tsutsui, A.; Takeda, H.; Kimura, M.; Fujimoto, T.; Machinami, T. Novel enantiocontrol system with aminoacyl derivatives of glucoside as enamine-based organocatalysts for aldol reaction in aqueous media. *Tetrahedron Lett.* **2007**, *48*, 5213–5217. [CrossRef]

142. Miura, D.; Fujimoto, T.; Tsutsui, A.; Machinami, T. Stereoselective Synthesis of Ketoses by Aldol Reaction Using Water-Compatible Prolinamide Catalysts in Aqueous Media. *Synlett* **2013**, *24*, 1501–1504. [CrossRef]

143. Miura, D.; Machinami, T. Stereoselective Aldol Reaction in Aqueous Solution Using Prolinamido-Glycosides as Water-Compatible Organocatalysts. *Mod. Res. Catal.* **2015**, *4*, 20–27. [CrossRef]

144. Agarwal, J.; Peddinti, R.K. Highly efficient and solvent-free direct aldol reaction catalysed by glucosamine-derived prolinamide. *Tetrahedron Asymmetry* **2010**, *21*, 1906–1909. [CrossRef]

145. Agarwal, J.; Peddinti, R.K. Asymmetric Michael addition catalysed by sugar-based prolinamides in solvent-free conditions. *Tetrahedron Lett.* **2011**, *52*, 117–121. [CrossRef]

146. Agarwal, J.; Peddinti, R.K. Synthesis and Characterization of Monosaccharide Derivatives and Application of Sugar-Based Prolinamides in Asymmetric Synthesis. *Eur. J. Org. Chem.* **2012**, *2012*, 6390–6406. [CrossRef]

147. Jacquinet, J.-C.; Sinaÿ, P. Synthèse du methyl-2-acétamido-2-désoxy-β-D-glucofuranoside et de dérivés. *Carbohydr. Res.* **1974**, *32*, 101–114. [CrossRef]

148. Pedatella, S.; De Nisco, M.; Mastroianni, D.; Naviglio, D.; Nucci, A.; Caputo, R. Diastereo- and Enantioselective Direct Aldol Reactions in Aqueous Medium: A New Highly Efficient Proline-Sugar Chimeric Catalyst. *Adv. Synth. Catal.* **2011**, *353*, 1443–1446. [CrossRef]

149. De Nisco, M.; Pedatella, S.; Bektaş, S.; Caputo, R. D-Glucosamine in a chimeric prolinamide organocatalyst for direct asymmetric aldol addition. *Carbohydr. Res.* **2012**, *356*, 273–277. [CrossRef]

150. Shen, C.; Shen, F.; Zhou, G.; Xia, H.; Chen, X.; Liu, X.; Zhang, P. Novel carbohydrate-derived prolinamide as a highly efficient, recoverable catalyst for direct aldol reactions in water. *Catal. Commun.* **2012**, *26*, 6–10. [CrossRef]

151. Shen, C.; Liao, H.; Shen, F.; Zhang, P. Novel synthesis of carbohydrate-derived organocatalysts and their application in asymmetric aldol reactions. *Catal. Commun.* **2013**, *41*, 106–109. [CrossRef]

152. Borges-Gonzáles, J.; Feher-Voelger, A.; Crisóstomo, F.P.; Morales, E.Q.; Martín, T. Tetrahydropyran-Based Hybrid Dipeptides as Asymmetric Catalysts for Michael Addition of Aldehydes to β-Nitrostyrenes. *Adv. Synth. Catal.* **2017**, *359*, 576–583. [CrossRef]

153. Giuliano, R.M.; Jordan, A.D.; Gauthier, A.D.; Hoogsteen, K. Diastereofacial Selectivity of Diels-Alder Reactions of Carbohydrate-Derived Dienes and Their Carbocyclic Analogs. *J. Org. Chem.* **1993**, *58*, 4979–4988. [CrossRef]

154. Bhunia, A.; Schwardt, O.; Gäthje, H.; Gao, G.-P.; Kelm, S.; Benie, A.J.; Hricovini, M.; Peters, T.; Ernst, B. Consistent Bioactive Conformation of the Neu5Acα(2-3)Gal Epitope Upon Lectin Binding. *ChemBioChem* **2008**, *9*, 2941–2945. [CrossRef]

155. Carrillo, R.; Martín, V.S.; López, M.; Martín, T. Synthesis and cation complexation properties of new macrolides. *Tetrahedron* **2005**, *61*, 8177–8191. [CrossRef]

156. Snatzke, G.; Raza, Z.; Habuš, I.; Šunjic, V. Chiroptical properties of tetrahydropyran-3,4-diols and 2-hydroxymethyltetrahydropyran-3-ols derived from L-arabinose, D-galactose, D-glucose, and D-xylose, and enantioselectivity in reduction with their complexes. *Carbohydr. Res.* **1988**, *182*, 179–196. [CrossRef]

157. Borges-Gonzáles, J.; García-Monzón, I.; Martín, T. Conformational Control of Tetrahydropyran-Based Hybrid Dipeptide Catalysts Improves Activity and Stereoselectivity. *Adv. Synth. Catal.* **2019**, *361*, 2141–2147. [CrossRef]

158. Habuš, I.; Šunjic, V. Preparation of the Chiral Diol (2R,3R)-2-Hydroxymethyl-3-hydroxy-tetrahydropyran from D-Glucose via Reductive Rearrangement of Pseudo-D-glucal Triacetate. *Croat. Chem. Acta* **1985**, *58*, 321–330.

159. Feher-Voelger, A.; Borges-Gonzáles, J.; Morales, E.Q.; Carrillo, R.; Morales, E.Q.; Gonzáles-Platas, J.; Martín, T. Synthesis and Conformational Analysis of Cyclic Homooligomers from Pyranoid ε-Sugar Amino Acids. *Chem. Eur. J.* **2014**, *20*, 4007–4022. [CrossRef]

160. Wang, L.; Liu, J.; Miao, T.; Zhou, W.; Li, P.; Ren, K.; Zhang, X. Sugar-Based Pyrrolidine as a Highly Enantioselective Organocatalyst for Asymmetric Michael Addition of Ketones to Nitrostyrenes. *Adv. Synth. Catal.* **2010**, *352*, 2571–2578. [CrossRef]

161. Mondal, S.; Fan, E. Mild and Efficient Synthesis of Fmoc-Protected Amino Azides from Fmoc-Protected Amino Alcohols. *Synlett* **2006**, *2006*, 306–308. [CrossRef]

162. Kumar, T.P.; Balaji, S.V. Sugar amide-pyrrolidine catalyst for the asymmetric Michael addition of ketones to nitroolefins. *Tetrahedron Asymmetry* **2014**, *25*, 473–477. [CrossRef]
163. Austin, G.N.; Baird, P.D.; Fleet, G.W.J.; Peach, J.M.; Smith, P.W.; Watkin, D.J. 3,6-Dideoxy-3,6-imino-1,2-O-isopropylidene-α-D-glucofuranose as a divergent intermediate for the synthesis of hydroxylated pyrrolidines: Synthesis of 1,4-dideoxy-1,4-imino-L-gulitol, 1,4-dideoxy-1,4-imino-L-lyxitol, 2S,3S,4R-3,4-dihydroxyproline and (1S,2R,8S,8aR)-1,2,8-trihydroxyoctahydroindolizine [8-epi-swainsonine]. X-ray crystal structure of (1S,2R,8S,8aR)-1,2,8-trihydroxy-5-oxo-octahydroindolizine. *Tetrahedron* **1987**, *43*, 3095–3108.

164. Chandrasekhar, S.; Reddy, M.S.; Jagadeesh, B.; Prabhakar, A.; Rao, M.H.V.R.; Jagannadh, B. Formation of a Stable 14-Helix in Short Oligomers of Furanoid cis-β-Sugar-Amino Acid. *J. Am. Chem. Soc.* **2004**, *126*, 13586–13587. [CrossRef] [PubMed]

165. Ge, X.; Qian, C.; Chen, Y.; Chen, X. Novel carbohydrate-derived pyridinecarboxylic organocatalysts for the enantioselective reduction of imines with trichlorosilane. *Tetrahedron Asymmetry* **2014**, *25*, 596–601. [CrossRef]

166. Wakamatsu, H.; Itoh, M.; Natori, Y.; Yoshimura, Y. Synthesis of 2'-aminouridine derivatives as an organocatalyst for Diels-Alder reaction. *Nucleosides Nucleotides Nucleic Acids* **2020**, *39*, 365–383. [CrossRef]

167. McGee, D.P.C.; Vaughn-Settle, A.; Vargeese, C.; Zhai, Y. 2'-Amino-2'-deoxyuridine via an Intramolecular Cyclization of a Trichloroacetimidate. *J. Org. Chem.* **1996**, *61*, 781–785. [CrossRef]

168. Wynands, L.; Delacroix, S.; Van Nhien, A.N.; Soriano, E.; Marco-Contelles, J.; Postel, D. New glycosyl-α-aminotetrazole-based catalysts for highly enantioselective aldol reactions. *Tetrahedron* **2013**, *69*, 4899–4907. [CrossRef]

169. Len, C.; Postel, D.; Mackenzie, G.; Villa, P.; Ronco, G. Strategy for the Preparation of 2' and 3' Branched Nucleosides. *Pharm. Pharmacol. Commun.* **1999**, *5*, 165–168. [CrossRef]

170. Domínguez, L.; Van Nhien, A.N.; Tomassi, C.; Len, C.; Postel, D.; Marco-Contelles, J. Synthesis of 4-Amino-5-*H*-2,3-dihydroisothiazole-1,1-dioxide Ring Systems on Sugar Templates via Carbanion-Mediated Sulfonamide Intramolecular Cyclization Reactions (CSIC Protocols) of Glyco-α-sulfonamidonitriles. *J. Org. Chem.* **2004**, *69*, 843–856. [CrossRef]

171. Muraoka, O.; Yoshikai, K.; Takahashi, H.; Minematsu, T.; Lu, G.; Tanabe, G.; Wang, T.; Matsuda, H.; Yoshikawa, M. Synthesis and biological evaluation of deoxy salacinols, the role of polar substituents in the side chain on the α-glucosidase inhibitory activity. *Bioorg. Med. Chem.* **2006**, *14*, 500–509. [CrossRef]

172. Sowa, W. Convenient synthesis of 3-amino-3-deoxy-D-ribose. *Can. J. Chem.* **1968**, *46*, 1586–1589. [CrossRef]

173. Van Nhien, A.N.; Domínguez, L.; Tomassi, C.; Torres, M.R.; Len, C.; Postel, D.; Marco-Contelles, J. Synthesis and transformations of [1,2-O-isopropylidene-α-D-erythro (and α-D-ribo) furanose]-3-spiro-3'-(-4'-amino-5'-H-2',3'-dihydroisothiazole-1',1'-dioxide) derivatives. *Tetrahedron* **2004**, *60*, 4709–4727. [CrossRef]

174. Mazur, A.; Tropp, B.E.; Engel, R. Isosteres of natural phosphates. 11. Synthesis of a phosphonic acid analogue of an oligonucleotide. *Tetrahedron* **1984**, *40*, 3949–3956. [CrossRef]

175. Fang, L.; Yan, L.; Haeffner, F.; Morken, J.P. Carbohydrate-Catalyzed Enantioselective Alkene Diboration: Enhanced Reactivity of 1,2-Bonded Diboron Complexes. *J. Am. Chem. Soc.* **2016**, *138*, 2508–2511. [CrossRef]

176. Pinheiro, D.L.J.; Batista, G.M.F.; Gonçalves, J.R.; Duarte, T.N.; Amarante, G.W. Sugar-Based Organocatalyst for the Diastereoselective Desymmetrization of Dibenzylideneacetones. *Eur. J. Org. Chem.* **2016**, *2016*, 459–462. [CrossRef]

177. Hoppe, I.; Schöllkopf, U.; Tölle, R. Asymmetrische Synthese von α-Methylaminosäure-methylestern unter Verwendung von D-Galactodialdehydals chiralem Hilfsreagens. *Synthesis* **1983**, *1983*, 789–791. [CrossRef]

178. Dwivedi, N.; Bisht, S.S.; Tripathi, R.P. Asymmetric organocatalysis with glycosyl-β-amino acids: Direct asymmetric aldol reaction of acetone with aldehydes. *Carbohydr. Res.* **2006**, *341*, 2737–2743. [CrossRef]

179. Meyer, A.S.; Reichstein, T. L-Idose aus L-glucose, sowie ein neuer Weg zur L-Idomethylose. *Helv. Chim. Acta* **1946**, *29*, 152–162. [CrossRef]

180. Wolfrom, M.L.; Hanessian, S. The Reaction of Free Carbonyl Sugar Derivatives with Organometallic Reagents. I. 6-Deoxy-L-idose and Derivatives. *J. Org. Chem.* **1962**, *27*, 1800–1804. [CrossRef]

181. Desai, V.N.; Saha, N.N.; Dhavale, D.D. Intramolecular Michael addition of benzylamine to sugar derived α,β-unsaturated ester: A new diastereoselective synthesis of a higher homologue of 1-deoxy-L-ido-nojirimycin. *Chem. Commun.* **1999**, *1999*, 1719–1720. [CrossRef]

182. Tronchet, J.M.J.; Gentile, B. Réaction d'ylures stabilisés sur des aldéhydosucres: Influence de divers facteurs dont la structure de l'aldéhydosucres sur le pourcentage d'isomères géométriques obtenu. *Helv. Chim. Acta* **1979**, *62*, 2091–2098. [CrossRef]

183. Ge, X.; Qian, C.; Chen, X. Synthesis of novel carbohydrate-based valine-derived formamide organocatalysts by CuAAC click chemistry and their application in asymmetric reduction of imines with trichlorosilane. *Tetrahedron Asymmetry* **2014**, *25*, 1450–1455. [CrossRef]

184. Goddard-Borger, E.D.; Stick, R.V. An Efficient, Inexpensive, and Shelf-Stable Diazotransfer Reagent: Imidazole-1-sulfonyl Azide Hydrochloride. *Org. Lett.* **2007**, *9*, 3797–3800. [CrossRef]

185. Becker, C.; Hoben, C.; Kunz, H. Enantioselective Organocatalysis of Strecker and Mannich Reactions Based on Carbohydrates. *Adv. Synth. Catal.* **2007**, *349*, 417–424. [CrossRef]

186. Negru, M.; Schollmeyer, D.; Kunz, H. Enantioselective Strecker Reaction Catalyzed by an Organocatalyst Lacking a Hydrogen-Bond-Donor Function. *Angew. Chem. Int. Ed.* **2007**, *46*, 9339–9341. [CrossRef]

187. Kunz, H.; Sager, W.; Schanzenbach, D.; Decker, M. Carbohydrates as Chiral Templates: Stereoselective Strecker Synthesis of D-α-Amino Nitriles and Acids Using O-Pivaloylated D-Galactosylamine as the Auxiliary. *Liebigs Ann. Chem.* **1991**, *1991*, 649–654. [CrossRef]
188. Armstrong, A.; Ahmed, G.; Garnett, I.; Goacolou, K.; Wailes, J.S. Exocyclic iminium salts as catalysts for alkene epoxidation by Oxone. *Tetrahedron* **1999**, *55*, 2341–2352. [CrossRef]

189. Page, P.C.B.; Buckley, B.R.; Appleby, L.F.; Alsters, P.A. Highly Efficient Catalysts for Epoxidation Mediated by Iminium Salts. *Synthesis* **2005**, *2005*, 3405–3411. [CrossRef]

190. Page, P.C.B.; Chan, Y.; Liddle, J.; Elsegood, M.R.J. Carbohydrate-derived iminium salt organocatalysts for the asymmetric epoxidation of alkenes. *Tetrahedron* **2014**, *70*, 7283–7305. [CrossRef]

191. Dorsey, A.D.; Barbarow, J.E.; Trauner, D. Reductive Cyclization of δ-Hydroxy Nitriles: A New Synthesis of Glycosylamines. *Org. Lett.* **2003**, *5*, 3237–3239. [CrossRef] [PubMed]

192. Catelani, G.; Colonna, F.; Marra, A. An improved preparation of 3,4-O-isopropylidene derivatives of α- and β-D-galactopyranosides. *Carbohydr. Res.* **1988**, *182*, 297–300. [CrossRef]

193. Chitale, S.; Derasp, J.S.; Hussain, B.; Tanveer, K.; Beauchemin, A.M. Carbohydrates as efficient catalysts for the hydration of α-amino nitriles. *Chem. Commun.* **2016**, *52*, 13147–13150. [CrossRef] [PubMed]

194. Singh, N.; Pandey, J.; Tripathi, R.P. D-Glucosamine, a natural aminosugar as organocatalyst for an ecofriendly direct aldol reaction of ketones with aromatic aldehydes in water. *Catal. Commun.* **2008**, *9*, 743–746. [CrossRef]

195. Agarwal, J.; Peddinti, R.K. Glucosamine-Based Primary Amines as Organocatalysts for the Asymmetric Aldol Reaction. *J. Org. Chem.* **2011**, *76*, 3502–3505. [CrossRef]

196. Sharma, A.; Peddinti, R.K. Direct Asymmetric Mannich Reaction Catalyzed by a D-Glucosamine-Derived Organocatalyst. *Synlett* **2018**, *29*, 630–634.

197. Shen, C.; Shen, F.; Xia, H.; Zhang, P.; Chen, X. Carbohydrate-derived alcohols as organocatalysts in enantioselective aldol reactions of isatins with ketones. *Tetrahedron Asymmetry* **2011**, *22*, 708–712. [CrossRef]

198. Shen, C.; Xia, H.J.; Zheng, H.; Zhang, P.; Chen, X. Synthesis of novel carbohydrate-based iminophosphinite ligands in Pd-catalyzed asymmetric allylic alkylations. *Tetrahedron Asymmetry* **2010**, *21*, 1936–1941. [CrossRef]

199. Li, L.; Fang, Z.; Fang, J.; Zhoub, J.; Xiang, Y. D-Fructose-derived β-amino alcohol catalyzed direct asymmetric aldol reaction in the presence of *p*-nitrophenol. *RSC Adv.* **2013**, *3*, 21084–21091. [CrossRef]

200. Li, L.; Fang, Z. Synthesis of novel β-amino-alcohols from D-fructose. *Chem. Res. Appl.* **2012**, *24*, 146–150.

201. Vanlaldinpuia, K.; Bora, P.; Bez, G. Monofunctional primary amine: A new class of organocatalyst for asymmetric Aldol reaction. *J. Chem. Sci.* **2017**, *129*, 301–312. [CrossRef]

202. Guo, J.; Frost, J.W. Biosynthesis of 1-Deoxy-1-imino-D-erythrose 4-Phosphate: A Defining Metabolite in the Aminoshikimate Pathway. *J. Am. Chem. Soc.* **2002**, *124*, 528–529. [CrossRef]

203. Vanlaldinpuia, K.; Bora, P.; Basumatary, G.; Mohanta, R.; Bez, G. Enantioselective aminocatalysis: Michael addition of unactivated ketones to nitroolefins catalyzed by D-fructose derived monofunctional primary amine. *J. Chem. Sci.* **2017**, *129*, 1603–1610. [CrossRef]

204. Reddy, K.R.; Rajgopal, K.; Maheswari, C.U.; Kantam, M.L. Chitosan hydrogel: A green and recyclable biopolymer catalyst for aldol and Knoevenagel reactions. *New J. Chem.* **2006**, *30*, 1549–1552. [CrossRef]

205. Kühbeck, D.; Saidulu, G.; Reddy, K.R.; Díaz, D.D. Critical assessment of the efficiency of chitosan biohydrogel beads as recyclable and heterogeneous organocatalyst for C–C bond formation. *Green Chem.* **2012**, *14*, 378–392. [CrossRef]

206. Rani, D.; Singla, P.; Agarwal, J. ‘Chitosan in water’ as an eco-friendly and efficient catalytic system for Knoevenagel condensation reaction. *Carbohydr. Polym.* **2018**, *202*, 355–364. [CrossRef]

207. Anbu, N.; Hariharan, S.; Dhakshinamoorthy, A. Knoevenagel-Doebner condensation promoted by chitosan as a reusable solid base catalyst. *Mol. Catal.* **2020**, *484*, 110744. [CrossRef]

208. Anbu, N.; Maheswari, R.; Elamathi, V.; Varalakshmi, P.; Dhakshinamoorthy, A. Chitosan as a biodegradable heterogeneous catalyst for Knoevenagel condensation between benzaldehydes and cyanoacetamide. *Catal. Commun.* **2020**, *138*, 105954. [CrossRef]

209. Hirayama, Y.; Kanomata, K.; Hatakeyama, M.; Kitaoka, T. Chitosan nanofiber-catalyzed highly selective Knoevenagel condensation in aqueous methanol. *RSC Adv.* **2020**, *10*, 26771–26776. [CrossRef]

210. Kayser, H.; Müller, C.R.; García-González, C.A.; Smirnova, I.; Leitner, W.; de María, P.D. Dried chitosan-gels as organocatalysts for the production of biomass-derived platform chemicals. *Appl. Catal. A Gen.* **2012**, *445–446*, 180–186. [CrossRef]

211. De Vylder, A.; Lauwaert, J.; De Clercq, J.; Van Der Voort, P.; Stevens, C.V.; Thybaut, J.W. Kinetic evaluation of chitosan-derived catalysts for the aldol reaction in water. *React. Chem. Eng.* **2019**, *4*, 1948–1956. [CrossRef]

212. Siddiqui, I.R.; Rai, P.; Rahila, Srivastava, A. Chitosan: An efficient promoter for the synthesis of 2-aminopyrimidine-5-carbonitrile derivatives in solvent free conditions. *New J. Chem.* **2014**, *38*, 3791–3795. [CrossRef]

213. Sahu, P.K.; Gupta, S.K.; Agarwal, D.D. Chitosan: An Efficient, Reusable, and Biodegradable Catalyst for Green Synthesis of Heterocycles. *Ind. Eng. Chem. Res.* **2014**, *53*, 2085–2091. [CrossRef]

214. Shivhare, K.N.; Siddiqui, I.R. Chitosan: A Natural and Sustainable Polymeric Organocatalyst for C-C Bond Formation During the Synthesis of 5-amino-2,3-dihydrobenzo[d]thiazole-4,6-dicarbonitriles. *Curr. Organocatal.* **2019**, *6*, 69–76. [CrossRef]

215. Jose, T.; Sudheesh, N.; Shukla, R.S. Amino functionalized chitosan as a catalyst for selective solvent-free self-condensation of linear aldehydes. *J. Mol. Catal. A Chem.* **2010**, *333*, 158–166. [CrossRef]

216. Han, X.; Li, Y.; An, H.; Zhao, X.; Wang, Y. Chitosan-catalyzed n-butyraldehyde self-condensation reaction mechanism and kinetics. *Chin. J. Chem. Eng.* **2019**, *27*, 2447–2454. [CrossRef]
217. Valentin, R.; Molvinger, K.; Quignard, F.; Brunel, D. Supercritical CO₂ dried chitosan: An efficient intrinsic heterogeneous catalyst in fine chemistry. *New J. Chem.* **2003**, *27*, 1690–1692. [CrossRef]

218. Zhao, Y.; Tian, J.-S.; Qi, X.-H.; Han, Z.-N.; Zhuang, Y.-Y.; He, L.-N. Quaternary ammonium salt-functionalized chitosan: An easily recyclable catalyst for efficient synthesis of cyclic carbonates from epoxides and carbon dioxide. *J. Mol. Catal. A Chem.* **2007**, *271*, 284–289. [CrossRef]

219. Dekamin, M.G.; Azimoshan, M.; Ramezani, L. Chitosan: A highly efficient renewable and recoverable bio-polymer catalyst for the expeditious synthesis of α-amino nitriles and imines under mild conditions. *Green Chem.* **2013**, *15*, 811–820. [CrossRef]

220. Rao, S.N.; Mohan, D.C.; Adimurthy, S. Chitosan: An efficient recyclable catalyst for transamidation of carboxamides with amines under neat conditions. *Green Chem.* **2014**, *16*, 4122–4126.

221. Reddy, S.R.S.; Reddy, B.R.P.; Reddy, P.V.G. Chitosan: Highly efficient, green, and reusable biopolymer catalyst for the synthesis of alkylaminophenols via Petasis borono–Mannich reaction. *Tetrahedron Lett.* **2015**, *56*, 4984–4989. [CrossRef]

222. Zhaleh, S.; Hazeri, N.; Faghihi, M.R.; Maghsoodlou, M.T. Chitosan: A sustainable, reusable and biodegradable organocatalyst for green synthesis of 1,4-dihydropyridine derivatives under solvent-free condition. *Res. Chem. Intermed.* **2016**, *42*, 8069–8081. [CrossRef]

223. Asghari-Haji, F.; Rad-Moghadam, K.; Mahmoodi, N.O. An efficient approach to bis-benzoquinonylmethanes on water under catalysis of the bioderived O-carboxymethyl chitosan. *RSC Adv.* **2016**, *6*, 27388–27394. [CrossRef]

224. Shelke, P.B.; Mali, S.N.; Chaudhari, H.K.; Pratap, A.P. Chitosan hydrochloride mediated efficient, green catalysis for the synthesis of perimidine derivatives. *J. Heterocycl. Chem.* **2019**, *56*, 3048–3054. [CrossRef]

225. Tsutsumi, Y.; Koga, H.; Qi, Z.-D.; Saito, T.; Isogai, A. Nanofibrillar Chitin Aerogels as Renewable Base Catalysts. *Biomacromolecules* **2014**, *15*, 4314–4319. [CrossRef]

226. Koga, H.; Kitaoka, T.; Isogai, A. *In situ* modification of cellulose paper with amino groups for catalytic applications. *J. Mater. Chem.* **2011**, *21*, 9356–9361. [CrossRef]

227. Kumar, K.S.; Krishna, B.S.; Reddy, C.B.; Reddy, M.V.N.; Reddy, C.S. Solvent-free synthesis of α-aminophosphonates: Cellulose-SO₃H as an efficient catalyst. *Arab. J. Chem.* **2017**, *10*, S368–S375. [CrossRef]

228. Ricci, A.; Bernardi, L.; Gioia, C.; Vierucci, S.; Robitzer, M.; Quignard, F. Chitosan aerogel: A recyclable, heterogeneous organocatalyst for the asymmetric direct aldol reaction in water. *Chem. Commun.* **2010**, *46*, 6288–6290. [CrossRef]

229. Gioia, C.; Ricci, A.; Bernardi, L.; Bourahla, K.; Tanchoux, N.; Robitzer, M.; Quignard, F. Chitosan Aerogel Beads as a Heterogeneous Organocatalyst for the Asymmetric Aldol Reaction in the Presence of Water: An Assessment of the Effect of Additives. *Eur. J. Org. Chem.* **2013**, *2013*, 588–594. [CrossRef]

230. Dong, H.; Liu, J.; Ma, L.; Ouyang, L. Chitosan Aerogel Catalyzed Asymmetric Aldol Reaction in Water: Highly Enantioselective Construction of 3-Substituted-3-hydroxy-2-oxindoles. *Catalyst* **2016**, *6*, 186. [CrossRef]

231. Heckel, T.; Konieczna, D.D.; Wilhelm, R. An Ionic Liquid Solution of Chitosan as Organocatalyst. *Catalyst* **2013**, *3*, 914–921. [CrossRef]

232. Qin, Y.; Zhao, W.; Yang, L.; Zhang, X.; Cui, Y. Chitosan-Based Heterogeneous Catalysts for Enantioselective Michael Reaction. *Chirality* **2012**, *24*, 640–645. [CrossRef]

233. Zhao, W.; Qu, C.; Yang, L.; Cui, Y. Chitosan-supported cinchonine as an efficient organocatalyst for direct asymmetric aldol reaction in water. *Chin. J. Catal.* **2015**, *36*, 367–371. [CrossRef]

234. Abdelkawy, M.A.; Aly, E.A.; El-Badawi, M.A.; Itsuno, S. Chitosan-supported cinchona urea: Sustainable organocatalyst for asymmetric Michael reaction. *Catal. Commun.* **2020**, *146*, 106132. [CrossRef]

235. Zhang, H.; Zhao, W.; Zou, J.; Liu, Y.; Li, R.; Cui, Y. Aldol Reaction Catalyzed by a Hydrophilic Catalyst in Aqueous Micelle as an Enzyme Mimic System. *Chirality* **2009**, *21*, 492–496. [CrossRef]

236. Andrés, J.M.; González, F.; Maestro, A.; Pedrosa, R.; Valle, M. Biodegradable Chitosan-Derived Thioureas as Recoverable Supported Organocatalysts—Application to the Stereoselective Aza-Henry Reaction. *Eur. J. Org. Chem.* **2017**, 3658–3665. [CrossRef]

237. Andrés, J.M.; Maestro, A.; Rodríguez-Ferrer, P.; Simón, I.; Pedrosa, R. Short Synthesis of Novel Recyclable Chiral Bifunctional Thioureas from Aminoalkyl Polystyrene and their use as Organocatalysts in Stereoselective aza-Henry Reaction. *ChemistrySelect* **2016**, *1*, 5057–5061. [CrossRef]

238. Ikai, T.; Moro, M.; Maeda, K.; Kanoh, S. Synthesis of polysaccharide derivatives bearing pyridine N-oxide groups and their use as asymmetric organocatalysts. *Eur. React. Funct. Polym.* **2011**, *71*, 1055–1058. [CrossRef]

239. For a review, see: Małkosza, M.; Fedoryński, M. Interfacial Processes—The Key Steps of Phase Transfer Catalyzed Reactions. *Catalysts* **2020**, *10*, 1436. [CrossRef]

240. Starks, C.M. Phase-transfer catalysis. I. Heterogeneous reactions involving anion transfer by quaternary ammonium and phosphonium salts. *J. Am. Chem. Soc.* **1971**, *93*, 195–199.

241. For a review, see: Nakamura, T.; Okuno, K.; Nishiyori, R.; Shirakawa, S. Hydrogen-Bonding Catalysis of Alkyl-Onium Salts. *Chem. Asian J.* **2020**, *15*, 463–472. [CrossRef]

242. For a review, see: Ooi, T.; Maruoka, K. Recent advances in asymmetric phase-transfer catalysis. *Angew. Chem. Int. Ed.* **2007**, *46*, 4222–4266. [CrossRef]

243. For a review, see: Wang, H. Chiral Phase-Transfer Catalysts with Hydrogen Bond: A Powerful Tool in the Asymmetric Synthesis. *Catalysts* **2019**, *9*, 244. [CrossRef]
244. For a review, see: Kaneko, S.; Kumatabara, Y.; Shirakawa, S. A new generation of chiral phase-transfer catalysts. *Org. Biomol. Chem.* **2016**, *14*, 5367–5376. [CrossRef]

245. Pedersen, C.J.; Frensdorff, H.K. Macrocyclic Polyethers and Their Complexes. *Angew. Chem. Int. Ed. Engl.* **1972**, *11*, 16–25. [CrossRef]

246. Liotta, C.L.; Harris, H.P.J. The Chemistry of “Naked” Anions. I. Reactions of the 18-Crown-6 Complex of Potassium Fluoride with Organic Substrates in Aprotic Organic Solvents. *J. Am. Chem. Soc.* **1974**, *96*, 2250–2252. [CrossRef]

247. Cram, D.; Sogah, G.D.Y. Chiral crown complexes catalyse Michael addition reactions to give adducts in high optical yields. *J. Chem. Soc. Chem. Commun.* **1981**, *1981*, 625–628. [CrossRef]

248. Nemcsok, T.; Rapi, Z.; Bagi, P.; Bakó, P. Synthesis and application of novel carbohydrate-based ammonium and triazolium salts. *Synth. Commun.* **2019**, *49*, 2388–2400. [CrossRef]

249. Hicks, D.R.; Fraser-Reid, B. Selective sulphonylation with N-Tosylimidazole. A one-Step Preparation of Methyl 2,3-Anhydro-4,6-O-benzylidene-α-D-mannopyranoside. *Synthesis* **1974**, *1974*, 203–204. [CrossRef]

250. Comba, M.B.; Mangione, M.I.; Suárez, A.G.; Sarotti, A.M.; Spanevello, R.A. A Domino Epoxide Ring-Opening Xanthate Migration Reaction: An Alternative Entry to Thiosugars. *Eur. J. Org. Chem.* **2018**, *2018*, 6848–6856. [CrossRef]

251. Goyal, N.; Cheuk, S.; Wang, G. Synthesis and characterization of D-glucosamine-derived low molecular weight gelators. *Tetrahedron* **2010**, *66*, 5962–5971. [CrossRef]

252. Dehmlow, E.V.; Sauerbier, C. Enantioselektive Phasen transfer-Katalyse durch optisch aktive Kronenether. *Liebigs Ann. Chem.* **1989**, *1989*, 181–185. [CrossRef]

253. Curtis, W.D.; Laidler, D.A.; Stoddart, J.F.; Jones, G.H. Synthesis of configurationally chiral cryptands and cryptates from carbohydrate precursors. *J. Chem. Soc. Chem. Commun.* **1975**, 1975, 833–835. [CrossRef]

254. Nemcsok, T.; Rapi, Z.; Keglevich, G.; Grün, A.; Bakó, P. Synthesis of D-mannitol-based crown ethers and their application as catalyst in asymmetric phase transfer reactions. *Chirality* **2018**, *30*, 407–419. [CrossRef] [PubMed]

255. Sugiyama, T.; Sugawara, H.; Watanabe, M.; Yamashita, K. Facile synthesis of 1,2,5,6-Di-O-cyclohexylidene-D-mannitol and 2,3-O-cyclohexylidene-D-glyceraldehyde. *Agric. Biol. Chem.* **1984**, *48*, 1841–1844.

256. Banerjee, A.; Schepmann, D.; Köhler, J.; Würthwein, E.U.; Wünsch, B. Synthesis and SAR studies of chiral non-racemic dexoxadrol analogues as uncompetitive NMDA receptor antagonists. *Bioorg. Med. Chem.* **2010**, *18*, 7855–7867. [CrossRef] [PubMed]

257. Ness, A.T.; Hahn, R.M.; Hudson, C.S. The Acetolysis of Trimethylene-D-sorbitol. 2,4-Methylene-D-sorbitol and 1,3,2,4-Dimethylene-D-sorbitol. *J. Am. Chem. Soc.* **1944**, *66*, 665–670. [CrossRef]

258. Van Maarschalkerwaart, D.A.H.; Willard, N.P.; Pandit, U.K. Synthesis of Carbohydrate containing Crown Ethers and their application as Catalysts in Asymmetric Michael Additions. *Tetrahedron* **1992**, *48*, 8825–8840. [CrossRef]

259. Nakaya, T.; Imoto, M. Plastic Scintillators. II. The Synthesis of Some Distyrylbenzene Derivatives as Wavelength Shifters in Plastic Scintillators. *Bull. Chem. Soc. Jpn.* **1966**, *39*, 1547–1551. [CrossRef]

260. Kanakamma, P.P.; Mani, N.S.; Maitra, U.; Nair, V. Chiral crown ethers incorporating D-glucose. *J. Chem. Soc. Perkin Trans. 1* **1995**, 1995, 2339–2344. [CrossRef]

261. Vicent, C.; Martin-Lomas, M.; Penadés, S. New synthetic strategy to highly symmetric chiral macrocycles from carbohydrate derivatives. *Tetrahedron* **1989**, *45*, 3605–3612. [CrossRef]

262. Kaji, E.; Hosokawa, Y.; Watanabe, Y.; Kobayashi, M.; Yamakawa, M. Stereospecific access to β-mannosides from glucose-derived 1,2-orthoesters as glycosyl donors. *Heterocycles* **2003**, *61*, 459–470. [CrossRef]

263. Bakó, P.; Fenichel, L.; Tőke, L.; Czugler, M. Synthese und Komplexbildung von Kronenethern aus Methyl-4,6-O-benzyliden-α-D-glucopyranosid. *Liebigs Ann. Chem.* **1981**, *1981*, 1163–1171. [CrossRef]

264. Bakó, P.; Fenichel, L.; Tőke, L.; Toth, G. Cleavage of the acetal rings in bis (methyl 4,6-O-benzylidene-α-D-glucopyranosido)-18-crown-6. *Carbohydr. Res.* **1986**, *147*, 31–37. [CrossRef]

265. Tőke, L.; Bakó, P.; Keserű, G.M.; Albert, M.; Fenichel, L. Asymmetric Michael Addition and Deracemization of Enolate by Chiral Crown Ether. *Tetrahedron* **1998**, *54*, 213–222. [CrossRef]

266. Tőke, L.; Fenichel, L.; Albert, M. Asymmetric Michael Addition. Deracemization of Enolate by Chiral Crown Ether. *Tetrahedron Lett.* **1995**, *33*, 5951–5954. [CrossRef]

267. Alonso-Lopez, M.; Bernabe, M.; Fernandez-Mayoralas, A.; Jimenez-Barbero, J.; Martin-Lomas, M.; Penadés, S. Chiral macrocyclic compounds from lactose derivatives. *Carbohydr. Res.* **1986**, *150*, 103–109. [CrossRef]

268. Fernandez-Mayoralas, A.; Martin-Lomas, M. 4-O-β-D-Galactopyranosyl-3-O-methyl-D-glucose: A new synthesis and application to the evaluation of intestinal lactase. *Carbohydr. Res.* **1985**, *140*, 81–91. [CrossRef]

269. Fernandez-Mayoralas, A.; Martin-Lomas, M. Synthesis of 3- and 2'-fucosyl-lactose and 3,2'-difucosyl-lactose from partially benzylated lactose derivatives. *Carbohydr. Res.* **1986**, *154*, 95–101. [CrossRef]

270. Alonso-Lopez, M.; Barbat, J.; Fanton, E.; Fernandez-Mayoralas, A.; Gelas, J.; Horton, D.; Martin-Lomas, M.; Penadés, S. The acetonation of lactose and benzyl β-lactoside with 2-methoxypropene. *Tetrahedron* **1987**, *43*, 1169–1176. [CrossRef]

271. Alonso-Lopez, M.; Jimenez-Barbero, J.; Martin-Lomas, M.; Penadés, S. Synthesis, complexing properties and applications in asymmetric synthesis of bis-lacto-18-crown-6 compounds. *Tetrahedron* **1988**, *44*, 1535–1543. [CrossRef]

272. Alonso-Lopez, M.; Martin-Lomas, M.; Penadés, S. Asymmetric Michael reaction using macrocyclic lactose derivatives as chiral catalysts. *Tetrahedron Lett.* **1986**, *27*, 3551–3554. [CrossRef]
273. Dondoni, A.; Marra, A. Transformation of linear oligoketosides into macrocyclic neoglycoconjugates. *Tetrahedron Lett.* **2009**, *50*, 3593–3596. [CrossRef]

274. Dondoni, A.; Marra, A.; Scherrmann, M.-C.; Bertolasi, V. Chemical Synthesis of Linear and Cyclic Unnatural Oligosaccharides by Iterative Glycosidation of Ketoses. *Chem. Eur. J.* **2001**, *7*, 1371–1382. [CrossRef]

275. Dondoni, A.; Scherrmann, M.-C. Thiazole-Based Synthesis of Formyl C-Glycosides. *J. Org. Chem.* **1994**, *59*, 6404–6412. [CrossRef]

276. For a review on thiazolylketoses, see: Dondoni, A.; Marra, A. Thiazolylketoses: A new class of versatile intermediates for glycoside synthesis. *Chem. Commun.* **1999**, *1999*, 2133–2145. [CrossRef]

277. Koto, S.; Morishima, N.; Miyata, Y.; Zen, S. Preparation of 2,3,4,6-Tetra-O-benzyl-D-mannose. *Bull. Chem. Soc. Jpn.* **1976**, *49*, 2639–2640. [CrossRef]

278. For a review on the use of thiazole in carbohydrate chemistry, see: Dondoni, A.; Marra, A. Thiazole-mediated synthetic methodology. *Chem. Rev.* **2004**, *104*, 2557–2599. [CrossRef]

279. Gokel, G.W. Lariat ethers: From Simple Side-arms to Supramolecular System. *Chem. Soc. Rev.* **1992**, *21*, 39–47. [CrossRef]

280. Bakó, P.; Bakó, T.; Bisztray, K.; Szöllősy, A.; Nagy, K.; Tőke, L. Synthesis, Extraction Ability and Application in an Asymmetric Synthesis of Azacrown Ethers Derived from D-Mannitol. *J. Incl. Phenom. Macrocycl. Chem.* **2001**, *39*, 247–251. [CrossRef]

281. Bakó, T.; Bakó, P.; Keglevich, G.; Báthori, N.; Czugler, M.; Tatai, J.; Novák, T.; Parlagh, G.; Tőke, L. Enantioselective Michael addition of 2-nitropropane to chalcone analogues catalyzed by chiral azacrown ethers based on D-glucose and D-mannitol. *Tetrahedron Asymmetry* **2003**, *14*, 1917–1923. [CrossRef]

282. Bakó, T.; Bakó, P.; Bombicz, P.; Kubinyi, M.; Pál, K.; Bodor, S.; Makó, A.; Tőke, L. Phase-transfer catalyzed asymmetric epoxidation of chalcones using chiral crown ethers derived from D-glucose, D-galactose, and D-mannitol. *Tetrahedron Asymmetry* **2004**, *15*, 1589–1595. [CrossRef]

283. Nemcsok, T.; Rapi, Z.; Bagi, P.; Keglevich, G.; Bakó, P. Synthesis of xylal- and arabinal-based crown ethers and their application as asymmetric phase transfer catalysts. *Chirality* **2020**, *32*, 107–119. [CrossRef] [PubMed]

284. Bakó, P.; Kiss, T.; Tőke, L. Chiral Azacrown Ethers Derived from D-glucose as Catalysts for Enantioselective Michael Addition. *Tetrahedron Lett.* **1997**, *38*, 7259–7262. [CrossRef]

285. Bakó, P.; Novák, T.; Ludányi, K.; Pete, B.; Tőke, L.; Keglevich, G. D-Glucose-based azacrown ethers with a phosphonoalkyl side chain: Application as enantioselective phase transfer catalysts. *Tetrahedron Asymmetry* **1999**, *10*, 2373–2380. [CrossRef]

286. Bakó, P.; Czinege, E.; Bakó, T.; Czugler, M.; Tőke, L. Asymmetric C–C bond forming reactions with chiral crown catalysts derived from D-glucose and D-galactose. *Tetrahedron Asymmetry* **1999**, *10*, 4539–4551. [CrossRef]

287. Bakó, P.; Tőke, L. Novel Monoaza- and Diazacrown Ethers Incorporating Sugar Units and Their Extraction Ability towards Picrate Salts. *J. Incl. Phenom.* **1995**, *23*, 195–201. [CrossRef]

288. Novák, T.; Bakó, P.; Keglevich, G.; Dobó, A.; Vékey, K.; Tőke, L. Synthesis of D-Glucose-based Azacrown Ethers with Phosphinoxidoalkyl Side Chains and Their Application to an Enantioselective Reaction. *J. Incl. Phenom. Macrocycl. Chem.* **2001**, *40*, 207–212. [CrossRef]

289. Rapi, Z.; Bakó, P.; Drahos, L.; Keglevich, G. Side-Arm Effect of a Methyl α-D-Glucopyranoside Based Lariat Ether Catalysts in Asymmetric Syntheses. *Heteroat. Chem.* **2015**, *26*, 63–71. [CrossRef]

290. Itoh, T.; Shirakami, S. Synthesis of chiral azacrown ethers derived from α-D-glucose and their catalytic properties on the asymmetric Michael addition. *Heterocycles* **2001**, *55*, 37–43. [CrossRef]

291. Bakó, P.; Makó, A.; Keglevich, G.; Menyhárt, D.K.; Sefcsik, T.; Fekete, J. Alkali Metal- and Ammonium Picrate Extraction and Complex Forming Capabilities of D-Glucose and D-Mannose-based Lariat Ethers. *J. Incl. Phenom. Macrocycl. Chem.* **2006**, *55*, 295–302. [CrossRef]

292. Sóti, P.L.; Telkes, L.; Rapi, Z.; Tóth, A.; Vigh, T.; Nagy, Z.K.; Bakó, P.; Marosi, G. Synthesis of an Aza Chiral Crown Ether Grafted to Nanofibrous Silica Support and Application in Asymmetric Michael Addition. *J. Inorg. Organomet. Polym.* **2014**, *2*, 713–721. [CrossRef]

293. Makó, A.; Szöllősy, Á.; Keglevich, G.; Menyhárd, D.K.; Bakó, P.; Tőke, L. Synthesis of methyl α-D-glucopyranoside-based azacrown ethers and their application in enantioselective reactions. *Monatsh Chem.* **2008**, *139*, 525–535. [CrossRef]

294. Bakó, P.; Bajor, Z.; Tőke, L. Synthesis of novel chiral crown ethers derived from D-glucose and their application to an enantioselective Michael reaction. *J. Chem. Soc. Perkin Trans. 1* **1999**, 3651–3655. [CrossRef]

295. Murphy, P.V.; O’Brien, J.L.; Gorey-Feret, L.J.; Smith, A.B., III. Synthesis of novel HIV-1 protease inhibitors based on carbohydrate scaffolds. *Tetrahedron* **2003**, *59*, 2259–2271. [CrossRef]

296. Coppola, C.; Saggiomo, V.; Di Fabio, G.; De Napoli, L.; Montesarchio, D. Novel Amphiphilic Cyclic Oligosaccharides: Synthesis and Self-Aggregation Properties. *J. Org. Chem.* **2007**, *72*, 9679–9689. [CrossRef]

297. Nemcsok, T.; Rapi, Z.; Bagi, P.; Guan, Y.H.; Orbán, I.; Keglevich, G.; Bakó, P. Enantioselective cyclopropanation of conjugated cyanosulfones using carbohydrate-based crown ether catalysts. *Tetrahedron* **2020**, *76*, 130965. [CrossRef]

298. Bakó, P.; Vizvárdi, K.; Bajor, Z.; Tőke, L. Synthesis and application in asymmetric synthesis of azacrown ethers derived from D-glucose. *Chem. Commun.* **1998**, *1998*, 1193–1194. [CrossRef]

299. Bakó, P.; Vízvárdi, K.; Toppet, S.; Van der Eycken, E.; Hoornaert, G.J.; Tőke, L. Synthesis, extraction ability and application in asymmetric synthesis of azacrown ethers derived from D-glucose. *Tetrahedron* **1998**, *54*, 14975–14988. [CrossRef]

300. Jászay, Z.; Pham, T.S.; Németh, G.; Bakó, P.; Petneházy, I.; Tőke, L. Asymmetric Synthesis of Substituted α-Amino Phosphonates with Chiral Crown Ethers as Catalysts. *Synlett* **2009**, *2009*, 1429–1432. [CrossRef]
301. Pham, T.S.; Rapi, Z.; Bakó, Z.; Petneházy, I.; Stirling, A.; Jászay, Z. Enantioselective synthesis of substituted α-aminophosphonates catalysed by D-glucose-based crown ethers: Pursuit of the origin of stereoselectivity. *New J. Chem.* **2017**, *41*, 14945–14953. [CrossRef]

302. Rapi, Z.; Nemcsok, T.; Bagi, P.; Keglevich, G.; Bakó, P. Synthesis of chiral crown ethers derived from D-galactose and their application in enantioselective reactions. *Tetrahedron* **2019**, *75*, 3993–4004. [CrossRef]

303. Rapi, Z.; Grün, A.; Keglevich, G.; Stirling, A.; Bakó, P. Synthesis of α-D-galactose-based azacrown ethers and their application as enantioselective catalysts in Michael reactions. *New J. Chem.* **2016**, *40*, 7856–7865. [CrossRef]

304. Makó, A.; Menyhárd, D.K.; Bakó, P.; Keglevich, G.; Tőke, L. Theoretical study of the asymmetric phase-transfer mediated epoxidation of chalcone catalyzed by chiral crown ethers derived from monosaccharides. *J. Mol. Struct.* **2008**, *892*, 336–342. [CrossRef]

305. Bakó, P.; Makó, A.; Keglevich, G.; Kubinyi, M.; Pál, K. Synthesis of D-mannose-based azacrown ethers and their application in enantioselective reactions. *Tetrahedron Asymmetry* **2005**, *16*, 1861–1871. [CrossRef]

306. Szabó, T.; Rapi, Z.; Keglevich, G.; Szöllősy, Á.; Drahos, L.; Bakó, P. Synthesis of L-arabinose-based crown ethers and their application as enantioselective phase transfer catalysts. *Arkivoc* **2012**, *8*, 36–48. [CrossRef]

307. Rapi, Z.; Bakó, P.; Keglevich, G.; Szöllősy, Á.; Drahos, L.; Hegedűs, L. Synthesis of ribose and altrose based azacrown ethers and their application in an asymmetric Michael addition. *Carbohydr. Res.* **2013**, *365*, 61–68. [CrossRef]

308. Makó, A.; Bakó, P.; Szöllősy, Á.; Bakó, T.; Peltz, C.; Keglevich, P. Synthesis of chiral pyridino-15-crown-5 type ligands containing α-D-hexapyranoside unit and their application in asymmetric synthesis. *Arkivoc* **2009**, *7*, 165–179. [CrossRef]

309. Makó, A.; Rapi, Z.; Drahos, L.; Szöllősy, Á.; Keglevich, G.; Bakó, P. Enantioselective Michael Addition of 2-Nitropropane to Substituted Chalcones and Chalcone Analogues Catalyzed by Chiral Crown Ethers Incorporating an α-D-Glucose or an α-D-Mannose Unit. *Lett. Org. Chem.* **2010**, *7*, 424–431. [CrossRef]

310. Bakó, T.; Bakó, P.; Szöllősy, Á.; Czugler, M.; Keglevich, G.; Tőke, L. Enantioselective Michael reaction of 2-nitropropane with substituted chalcones catalysed by chiral azacrown ethers derived from α-D-glucose. *Tetrahedron Asymmetry* **2002**, *13*, 203–209. [CrossRef]

311. Novák, T.; Tatai, J.; Bakó, P.; Czugler, M.; Keglevich, G.; Tőke, L. Asymmetric Michael Addition Catalyzed by D-Glucose-based Azacrown Ethers. *Synlett* **2001**, *3*, 424–426. [CrossRef]

312. Bakó, P.; Tőke, L.; Szöllősy, A.; Bombicz, P. Asymmetric Michael Addition of 2-Nitropropane to a Chalcone Catalyzed by Chiral Crown Ethers Incorporating a D-glucose Unit. *Heteroat. Chem.* **1997**, *8*, 333–337. [CrossRef]

313. Bakó, P.; Szöllősy, A.; Bombicz, P.; Tőke, L. Asymmetric C-C Bond Forming Reactions by Chiral Crown Catalysts; Darzens Condensation and Nitroalkane Addition to the Double Bond. *Synlett* **1997**, *1997*, 291–292. [CrossRef]

314. Rapi, Z.; Démuth, B.; Keglevich, G.; Grün, G.; Drahos, L.; Sóti, P.L.; Bakó, P. Enantioselective Michael addition of malonates to aromatic nitroalkenes catalyzed by monosaccharide-based chiral crown ethers. *Tetrahedron Asymmetry* **2014**, *25*, 141–147. [CrossRef]

315. Bakó, P.; Zsolt, R.; Grün, A.; Nemcsok, T.; Hegedűs, L.; Keglevich, G. Asymmetric Michael Addition of Malonates to Enones Catalyzed by an α-D-Glucopyranoside-Based Crown Ether. *Synlett* **2015**, *26*, 1847–1851. [CrossRef]

316. Rapi, Z.; Nemcsok, T.; Grün, A.; Pálvölgyi, Á.; Samu, G.; Hessz, D.; Kubinyi, M.; Kállay, M.; Keglevich, G.; Bakó, P. Asymmetric cyclopropanation reactions catalyzed by carbohydrate-based crown ethers. *Tetrahedron* **2018**, *74*, 3512–3526. [CrossRef]

317. Bakó, P.; Bakó, T.; Mészáros, A.; Keglevich, G.; Szöllősy, Á.; Bodor, S.; Makó, A.; Tőke, L. Phase Transfer Catalysed Asymmetric Epoxidation of Chalcones Using Chiral Crown Ethers Derived from D-Glucose and D-Mannose. *Synlett* **2004**, *4*, 643–646. [CrossRef]

318. Bakó, P.; Rapi, Z.; Keglevich, G.; Szabó, T.; Sóti, P.L.; Vígh, T.; Grün, A.; Holczbauer, T. Asymmetric C–C bond formation via Darzens condensation and Michael addition using monosaccharide-based chiral crown ethers. *Tetrahedron Lett.* **2011**, *52*, 1473–1476. [CrossRef]

319. Rapi, Z.; Bakó, P.; Keglevich, G.; Szöllősy, A.; Drahos, L.; Botyánszki, L.; Holczbauer, T. Asymmetric phase transfer Darzens reactions catalyzed by D-glucose- and D-mannose-based chiral crown ethers. *Tetrahedron Asymmetry* **2012**, *23*, 489–496. [CrossRef]

320. Rapi, Z.; Szabó, T.; Keglevich, G.; Szöllősy, A.; Drahos, L.; Bakó, P. Enantioselective synthesis of heteroaromatic epoxyketones under phase-transfer catalysis using D-glucose- and D-mannose-based crown ethers. *Tetrahedron Asymmetry* **2011**, *22*, 1189–1196. [CrossRef]