bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthese von Plagiochin A und B, zwei macrocyclische Bis(bibenzylether) aus Plagiochila acantophylla
Authors: Kametler László , Keseru György M. , Nógrádi Mihály , Mezey‐Vándor Gabriella , Vermes Borbála , Kajtár‐Peredy MÁRia 
Published: July 2007

Synthesis of Plagiochins A and B, Macrocyclic Bis(bibenzyl) Ethers from Plagiochila acantophyllaPlagiochins A (1) and B (2), macrocyclic bis(bibenzyl) ethers with a 16‐membered ring, are synthesized. The key steps are the Pd(0)‐catalyzed C—C coupling of an areneboronic acid (18) with an aryl bromide with formation of a biphenyl (13), Ullmann ether synthesis of a diphenyl ether (23), Wittig reaction to connect the two components 13 and 23, and a modified Wurtz reaction to close the ring. The latter reaction is accompanied by an unusual transformation of a C‐benzyloxy to a C‐benzoyl group.
Reaction of 3‐Acetyl‐7,12‐dihydro‐2‐methyl‐6H‐indolo[2,3‐a]quinolizinium Chloride with Aromatic Aldehydes Forming “Dimers” under Kinetic Control; Stereoselective Acetal versus Aldol Ring Closure
Authors: Teuber Hans‐Joachim , Quintanilla‐Licea Ramiro , Bats Jan Willem 
Published: July 2007

Abstract3‐Acetyl‐7,12‐dihydro‐2‐methyl‐6H‐indolo[2,3‐a]quinolizinium chloride (1) forms “dimers” (5a, b) by condensation with benzaldehyde and by means of kinetically controlled acetal ring closure (piperidine catalysis). In 5a, b the two quinolizinium units are connected by intercalation of a hydrogenated chroman system whose reactivity is attributed to the presence of a pyranoid hemiacetal structure. On standing or heating of their solution 5a, b are converted via the intermediate 4 and aldol ring closure into the thermodynamically more stable diastereoisomers 2a, b with a bicyclo[3.3.1]nonadiene system. All the ring closures occur with diastereofacial selectivity. In the case of the condensation of 1 with salicylaldehyde the Schiff base of this aldehyde with aniline replaces the aldehyde moiety as well as the piperidine catalyst and yields 10a, b under kinetically controlled conditions. By sodium tetrahydridoborate reduction in methanol 5a is converted into 7, the X‐ray structural analysis of which confirms structure and stereochemistry.
1,3‐Dipolare Cycloaddition elektrophiler Azide an cyclische Keten‐N,X‐acetale. — Stickstoff‐Extrusion und Ringerweiterung der [3 + 2]‐Cycloaddukte
Authors: Quast Helmut , Ach Manfred , Peters Eva‐Maria , Peters Karl , Peters Karl , von Schnering Hans Georg 
Published: July 2007

1,3‐Dipolar Cycloaddition of Electrophilic Azides to Cyclic Ketene N,X‐Acetals. — Extrusion of Molecular Nitrogen and Ring Expansion of the [3 + 2] Cycloadducts.The electrophilic azides 2 react with cyclic ketene N,X‐acetals of type 7, e.g. 13, 15, 18, 21, 23, 25, and with the alkylidene‐dihydroindoles 28 as well, to produce, besides molecular nitrogen, ring‐expanded products of type 11 and 12, e.g. 14, 16, 19, 22, 24, 26, and 29 (path A), and/or N‐sulfonylimines 10, viz. 17, 20, 27, and 31, besides diazo compounds (path B). The configurations of 16b, 19, 24a, and 26a are elucidated by means of X‐ray diffraction analyses. The envelope conformations of the hetero rings of 19, 29 undergo ring inversion with rates in the range of the 1H NMR time scale [19: ΔG#c (285 K) = 54.8 kJmol−1, 29; ΔG#c (301 K) = 61.4, ΔG#c (314 K) = 60.7]. The formation of the ring‐expanded products 11 and 12 is interpreted in terms of an initial [3 + 2] cycloaddition leading to unstable spiro compounds 8. Opening of their dihydro‐1,2,3‐triazole ring generates the zwitterions 9 which lose molecular nitrogen with concomitant ring expansion by a 1,2‐shift of the more soft one of the atoms N and X.
What is the Structure of Peptide Antibiotic Tü 1718 B? Previously Proposed Structure Disproved by Synthesis
Authors: Postels Hans‐Thomas , König Wilfried A. 
Published: July 2007

AbstractTwo stereoisomers (1a and 1b) of N‐(L‐valyl)‐2′,5‐dihydroxyhomoproline, the proposed structure of the dipeptide antibiotic Tü 1718 B, were synthesized by starting from natural (2S,4R)‐hydroxyproline. The 1H‐ and 13C‐NMR spectra of 1a and 1b clearly differ from the corresponding spectra of the natural product. From both synthetic stereoisomers characteristic mass spectra were obtained after esterification and trifluoroacetylation. Isomer 1a is present as a mixture of two stable conformers, as indicated by peak splitting in the1H‐NMR spectra, which disappears at higher temperature, while 1b exits as a single conformer. Both synthetic stereoisomers are antibiotically inactive.
Iodocyclization of Homoallylic Hydroxylamines Derived from D‐Glyceraldehyde
Authors: Dhavale Dilip D. , Gentilucci Luca , Piazza Maria Giulia , Trombinl Claudio 
Published: July 2007

AbstractThe reaction of allylmagnesium chloride with nitrone 1 derived from D‐glyceraldehyde affords two diastereoisomeric homoallylic hydroxylamines 2a and 3a which, after separation and O‐silylation, are subjected to iodocyclization using N‐iodosuccinimide. The stereochemical outcome of the cyclization reaction was found to be different; thus, the hydroxylamine 2b is converted into a mixture of cis‐ and trans‐isoxazolidines 10 and 11 in which the trans product prevails, whereas 3b is stereoselectively converted into the cis product 12. The final 5‐(iodomethyl)isoxazolidines 10–12 may be easily subjected to further studies; for example they undergo iodine displacement by treatment with azide, phthalimide, and acetate ions to give 13–16, formal precursors of deoxy‐amino‐hexitols. As an example, 1‐O‐acetyl‐3,4‐dideoxy‐5,6‐O‐(1‐methylethylidene)‐4‐[(phenylmethyl)amino]‐D‐lyxo‐hexitol (17) is synthesized.
Synthesis of Sphingosine Relatives, XII Synthesis and Absolute Configuration of the Two Epimeric Aliphatic Amino Alcohols [5E, 7E)‐2‐Amino‐5,7‐tetradecadien‐3‐ols] Isolated from a Sponge, Xestospongia sp.
Authors: Mori Kenji , Matsuda Hiroyuki 
Published: July 2007

Abstract(2S, 3S, 5E, 7E)‐ and (2S, 3R, 5E, 7E)‐2‐Amino‐5,7‐tetradecadien‐3‐ol [(S)‐1a and (S)‐1b], which were proposed as the structures of epimeric amino alcohols isolated from a marine sponge, and their two enantiomers were synthesized from (S)‐ and (R)‐alanine, respectively. The high‐field 1H‐NMR spectra of the diacetyl derivatives of 1a, b were identical with those of the derivatives of naturally occurring amino alcohols. However, the absolute configurations of the natural products were corrected as (2R) by comparing the optical rotations of natural products with those of the synthetic products.
Synthesis of Novel HMG‐CoA Reductase Inhibitors, I. Naphthalene Analogs of Mevinolin
Authors: Novák Lajos , Rohály JáNos , Poppe László , Hornyánszky Gábor , Kolonits Pál , Zelei István , Fehér Imre , Fekete Jenö , Szabó Éva , Záhorszky Uwe , Jávor András , Szántay Csaba 
Published: July 2007

AbstractThe title compounds 2 and their corresponding (6 S) epimers 18 are prepared in several steps by starting with chiral formyl ester 5, and α‐tetralones 10: (1) coupling reaction with the ylide generated from 11 to yield unsaturated ester 13, (2) reduction to the corresponding alcohol 14, (3) addition of the Grignard reagent derived from 14 to formyl ester 5 to afford the hydroxy esters 16 and 17, and (4) lactonization. This procedure is also used to synthesize the β‐naphthyl analogs 29 and 30. Some results obtained from HMG‐CoA reductase inhibitor screening are also reported.
Chirale Porphyrine mit C‐verknüpften Menthyl‐Resten
Authors: Marx Thomas , Breitmaier Eberhard 
Published: July 2007

Chiral Porphyrins with C‐Connected Menthyl ResiduesChiral porphyrins 9 and 10 with C‐connected (—)‐menthyl residues are prepared starting from (—)‐menthol 1 in eight steps, finally involving cyclization of 3‐formyl‐β‐(p‐menth‐3‐yl)styrene (6) with pyrrole (7) or the 2,2′‐dipyrrylmethane 8.
Regioselectivity in Cyclofunctionalization of Olefinic Alcohols with Benzeneselenenyl Halides at Different Temperatures[1 – 4]
Authors: Konstantinovic Stanimir , Bugarčič Zorica , Milosavljevič Slobodan , Schroth Gerhard , Mihailovič Mihailo Lj. 
Published: July 2007

AbstractThe regioselectivity in cyclofunctionalization of some acyclic olefinic alcohols with benzeneselenenyl halides (PhSeCl and PhSeBr) at different temperatures (−78°C, O°C and room temperature) is investigated. It has been found that Δ4‐ and Δ5‐ alkenols are converted into five‐ and/or six‐membered cyclic phenyl selenoethers, the yield of which decreases with increasing reaction temperature. PhSeCl has been found to be more efficient than PhSeBr in the cyclization reactions.
Terpenes and Terpene Derivatives, XXVIII. New Monoterpene Derivatives from the Essential Oil of Artemisia salsoloides
Authors: Weyerstahl Peter , Wahlburg Hans‐Christian , Kaul Vijay K. , Lochynski Stanislaw 
Published: July 2007

AbstractFrom the essential oil of Artemisia salsoloides the oxygenated monoterpenes 1, and 3–8 could be isolated. The easy formation of the hydroperoxide 2 from 1 suggests a biogenetic pathway from geraniol/nerol to 3. By comparison, the synthesized 8 exhibits mushroom and celery odor, typical of fractions of the A. salsoloides oil containing 8.
Synthese von Chlorinen aus dem roten Blutfarbstoff Hämin
Authors: Haake Gerold , Meier Axel , Montforts Franz‐Peter , Scheurich Gerhard , Zimmermann Gottfried 
Published: July 2007

Synthesis of Chlorins from the Red Blood Pigment HemeHydroxyalkylporphyrins rac‐8h, k and rac‐9h, k prepared from the readily accessible red blood pigment heme can be transformed into the geminally dialkylated chlorins rac‐10–13 upon reaction with N,N‐dimethylacetamide dimethyl acetal. The chlorins are promising candidates for application in Photodynamic Tumor Therapy (PDT). The reported synthetic method should be useful for the synthesis of natural hydroporphyrins containing geminally dialkylated structural parts.
Synthesis of 4,7‐Dihydroxyperhydroisobenzofuran‐1‐one and Comparison with Zwergal's Structure of “garlicin”
Authors: Nour Reema Abdel , Schneider Karin , Urban Ernst 
Published: July 2007

AbstractThe Diels‐Alder reaction of 2‐(benzoyloxy)furan (2) with maleic anhydride leads to the adduct 3 which, on hydrogenation, affords the exo anhydride 4a (71%) and endo anhydride 4b (2.4%). The regioselective reduction of 4a and 4b with NaBH4 leads to the lactones 5a and 5b, respectively. Base‐catalyzed cleavage of 5a gives the keto lactone 6 or dimethyl acetal 7, depending on the reaction conditions. Catalytic hydrogenation of keto lactone 6 results in the diastereoselective formation of the title compound 8a which has been converted into the acetate 8b and trifluoroacetate 8c. The structure and properties of the dihydroxylactone 8a are discussed in comparison with garlic compound “garlicin”.
Irreversible Desaktivierung von menschlicher β‐Hexosaminidase A mit dem alkylierenden Pseudodisaccharid (3,4,6/5)‐6‐(2‐Acetamido‐2‐desoxy‐β‐D‐glucopyranosylthio)‐3,4‐epoxy‐5‐hydroxycyclohexen
Authors: Kuhn Cai‐Steffen , Lehmann Jochen , Sandhoff Konrad 
Published: July 2007

Irreversible Deactivation of Human β‐Hexosaminidase A with the Alkylating Pseudodisaccharide (3,4,6/5)‐6‐(2‐Acetamido‐2‐deoxy‐β‐D‐glucopyranosylthio) ‐3,4‐epoxy‐5‐hydroxycyclohexene(3,4,6/5)‐6‐(2‐Acetamido‐2‐deoxy‐β‐D‐glucopyranosylthio)‐3,4‐epoxy‐5‐hydroxycyclohexene (8b) has been synthesised and found to deactivate irreversibly human β‐D‐hexosaminidase from lysosomes. Deactivation did not take place in the presence of the competitive inhibitor (3,6/4,5)‐6‐(2‐acetamido‐2‐deoxy‐β‐D‐glucopyranosylthio)‐4‐bromo‐3,5‐dihydroxy‐cyclohexene (5a/b).
Pheromone Synthesis, CXXXVII. A New Synthesis of (+)‐Grandisol
Authors: Mori Kenji , Fukamatsu Kunio 
Published: July 2007

AbstractThe natural and (+)‐enantiomer of grandisol [1, (1R,2S)‐(+)‐2‐isopropenyl‐1‐methylcyclobutaneethanol] has been synthesized from (R)‐(—)‐carvone (2) by employing the intramolecular alkylation of 8 to give 9 as the key step.
Stereochemie der Addition von Phenylmetall‐Reagenzien an Bicyclo[3.3.0]octandione und ‐octadiendione. — Synthese phenylsubstituierter Bicyclo[3.3.0]octadiene
Authors: Quast Helmut , Carlsen Jürgen , Herkert Thomas , Janiak Rolf , Röschert Horst , Peters Eva‐Maria , Peters Karl , von Schnering Hans Georg 
Published: July 2007

Stereochemistry of the Addition of Phenylmetal Reagents to Bicyclo[3.3.0]octanediones and ‐octadienediones. — Synthesis of Phenyl‐Substituted Bicyclo[3.3.0]octadienesConjugate addition of dilithium diphenylcyanocuprate is observed only on one side of the dienedione 4b, affording the enedione 5b, but on both sides in the presence of boron trifluoride yielding the diphenyldione 6b. Likewise, the latter reagent gives rise to the formation of 6a from 4a. Phenylcerium(III) dichloride is much superior to phenyllithium and phenylmagnesium bromide in the 1,2 addition reaction to encumbered, enolizeable bicyclo[3.3.0]octanediones. Thus, a mixture of the diols exo,exo‐8, exo,endo‐8, and endo,endo‐8 is formed in almost quantitative yield from the 3,7‐dione 7. Furthermore, the diphenyldione 6a is transformed into the tetraphenyldiol 14 in this way and in high yield. The 2,6‐dione 11b adds phenylcerium(III) dichloride affording a mixture of the hydroxyketone endo‐16, which is inert towards an excess of the reagent, and the diol exo,endo‐12b. The inertness of endo‐16 is attributed to the formation of the cyclic hemiacetal 20 which eventually is trapped quantitatively by O‐silylation with chlorotrimethylsilane in the presence of pyridine. The hydroxyketone endo‐16 is dehydrated to give the enone 17 which subsequently is treated with phenylcerium(III) dichloride to form exo‐ and endo‐19. A solution of sulfuric acid in acetic acid dehydrates the tertiary benzyl alcohols 8 (→9 + 10), endo,endo‐12a (→ 13a), exo,endo‐12b (→ 13b), 14 (→ 15), endo‐16 (→ 17), and 19 (→ 13b) in high yields. The same results are achieved even more conveniently with a solution of chlorotrimethylsilane in dichloromethane in the absence of a base. The oxanortwistane 18 is obtained as a byproduct in the dehydration of exo,endo‐12b with both reagents. The gross structures of all compounds are based on spectroscopic evidence, in particular NMR spectra. Concentration‐independent IR and low‐field NMR absorptions of two equivalent hydroxy groups are indicative of intramolecular hydrogen bonds and hence the endo,endo configuration of the diols endo,endo‐8, endo,endo‐12a, and 14. Eventually, the configurations of 5b, 6b, endo,endo‐8, endo,endo‐12a, exo,endo‐12b, 14, 15, endo‐16, and the structure of 18 as well, are established by X‐ray diffraction analyses. In the solid state, the bicyclo[3.3.0]‐octanols endo,endo‐12a, exo,endo‐12b, 14, and endo‐16 adopt conformations that allow the phenyl groups the occupation of quasi equatorial positions. The optimized procedures described open high‐yield routes to phenyl‐substituted bicyclo‐[3.3.0]octadienes starting from readily available bicyclooctanediones.
Synthesis of α‐Arabinose Nucleosides from 6‐Substituted Uracils
Authors: Jørgensen Per T. , El‐Barbary Ahmed A. , Pedersen Erik B. 
Published: July 2007

AbstractThe reaction of silylated 6‐substituted uracils 5 with methyl 2,3,5‐tri‐O‐benzoyl‐α‐D‐arabinofuranoside (3) in the presence of trimethylsilyl trifluoromethanesulfonate (TMS triflate) afforded a mixture of the corresponding protected N1,N3‐bis(arabinofuranosyl)uracils 6 and the 6‐substituted 2,3,5‐tri‐O‐benzoyl‐α‐D‐arabinofuranosyluracils 8. Deprotection of 6 and 8 gave the corresponding α nucleosides 7 and 9. The reaction of silylated 6‐ethyl‐ and 6‐methylthiouracil with 3 afforded a mixture of S‐ and N3‐glycosides 10 and 11. The glycosides 10 were deblocked by treatment with methanolic ammonia to obtain the deprotected α nucleosides 12.
Some Synthetic Studies Related to Perylenequinones
Authors: Zhao Chen , Zhang Xu‐Sheng , Zhang Pang 
Published: July 2007

AbstractTwo closely related routes to dimethyl 3,10‐dihydro‐2,11‐dihydroxy‐4,6,7,9‐tetramethoxy‐3,10‐dioxo‐1,12‐perylenediacetate (10), one involving Ullmann phenol coupling and the other by double oxidative coupling are described. Regioselective demethylation of 10 followed by methylation or vice versa yields dimethyl 3,10‐dihydro‐4,9‐dihydroxy‐2,6,7,11‐tetramethoxy‐3,10‐dioxo‐1,12‐perylenediacetate (22) which, except for its side chains, structurally resembles some of the natural perylenequinones.
Stereochemie von Aldolreaktionen mit 3‐Hexulose‐Phosphat‐Synthase
Authors: Brockamp Hans‐Peter , Steigel Alois , Kula Maria‐Regina 
Published: July 2007

Stereochemistry of Aldol Reactions with 3‐Hexulose Phosphate SynthaseThe enzymic reaction between ribulose‐5‐phosphate (1) and formaldehyde or acetaldehyde catalyzed by hexulose phosphate synthase (HPS) from Methylomonas M 15 DSM 580 yielded D‐arabino‐3‐hexulose‐6‐phosphate (2) and two new 7‐deoxy‐4‐heptulose‐1‐phosphates (4, 6). By various NMR‐spectroscopic methods, especially NOED, the configuration of the dephosphorylated products was established as (5R,6S) and (5R,6R). The configuration of two earlier described 7,8‐dideoxy‐4‐octulose‐1‐phosphates (8, 10) synthesized likewise by HPS catalysis must be corrected.
Refunctionalization of Homoallylic Alcohols Containing a Vinylic Chlorine Atom
Authors: Hoffmann Reinhard W. , Giesen Volker , Fuest Marcus 
Published: July 2007

AbstractThe chlorine atoms in Z‐substituted vinyl chlorides 1, 5, 7 and 14 have been replaced by alkyl, vinyl and (trimethylsilyl)methyl groups to give the alkenes 3, 4, the dienes 9, 10, 15, or the allylsilanes 8. The latter have been transformed stereoselectively into tri‐ and tetrasubstituted tetrahydrofurans 18 and 20. The vinyl chlorides 1 have been converted into the corresponding Z‐vinylsilanes 13 and 23. These serve as starting compounds for the stereoselective generation of trisubstituted 5,6‐dihydro‐2H‐pyrans 25, 26, 28, and 30. Derivatives 31 and 34 of the vinyl chlorides 1 have been subjected to stereoselective free‐radical cyclizations giving substituted tetrahydropyrans 33 and 35. The vinyl chlorides 1 may readily be converted to the alkynes 37.
Easy and General Method for the Preparation of m‐ and p‐Acylbenzoic Acids: A New Synthesis of rac‐Suprofen
Authors: Camps Pelayo , Giénezm Silvia , Farrés Xavier , Mauleón David , Carganico Germano 
Published: July 2007

AbstractA method for the preparation of m‐ and p‐acylbenzoic acids 3 based on the Claisen condensation of isophthalic or terephthalic diesters 1 with α‐methylenecarboxylic esters 2 is described. p‐Propionylbenzoic acid p‐4 (R = Me) is used in a new synthesis of rac‐suprofen (11).
Pheromone Synthesis, CLI. Synthesis of Chlorinated Steroids Related to the Structures Proposed for Blattellastanosides A and B, the Aggregation Pheromone of the German Cockroach, Blattella germanica L.
Authors: Mori Kenji , Fukamatsu Kunio , Kido Masaru 
Published: July 2007

AbstractRemote functionalization of 5α‐stigmastan‐3β‐ol (5) to yield eventually 5α‐stigmast‐9(11)‐en‐3α‐ol (8) was employed for the syntheses of 9α‐chloro‐5α‐stigmastane‐3β,11β‐diol (13) and 12α‐chloro‐9α,11α‐epoxy‐5α‐stigmastan‐3β‐yl β‐D‐glucopyranoside (3). The former (13) was the aglycone part of the structure 2 originally proposed for blattellastanoside B, and the latter (3) was exactly the structure proposed for blattellastanoside A, the components of the aggregation pheromone of the German cockroach, Blattella germanica L. The present work disproved the structures 1–4 proposed for blattellastanosides A and B.
Synthetic Microbial Chemistry, XXV. Synthesis of the Enantiomers of Differolide [4‐(2′,5′‐Dihydro‐2′‐oxo‐3′‐furanyl)‐3a,4,5,6‐tetrahydro‐1(3H)‐isobenzofuranone], a Microbial Bioregulator for the Formation of Aerial Mycelium and Spores of Streptomyces glaucescens
Authors: Mori Kenji , Tomioka Hiroki , Fukuyo Emiko , Yanagi Kazunori 
Published: July 2007

AbstractBoth the enantiomers of differolide [4‐(2′,5′‐dihydro‐2′‐oxo‐3′‐furanyl)‐3a,4,5,6‐tetrahydro‐1(3H)‐isobenzofuranone (1)] were synthesized by starting from the known lactone rac‐2. The key step was the optical resolution of hemiacetal rac‐3 by acetal formation with (+)‐ or (−)‐menthol. A single crystal X‐ray analysis of acetal (−)‐4a established its absolute configuration. Since the natural product was known to be racemic, the present synthesis of both (+)‐ and (−)‐1 with known absolute configuration provided molecular probes to examine the enantioselectivity at the receptor site of Streptomyces glaucescens.
Synthesis of 2,3‐Dihydro‐7‐hydroxymethyl‐1H‐pyrrolizin‐1‐one, the Alkaloid Loroquine
Authors: Röder Erhard , Bartkowski Jan‐Pit Barko , Bourauel Thomas 
Published: July 2007

AbstractThe title compound 4 is synthesized in 8 steps by cyclization of N‐tosylglycinate 5 with vinyl ketone 6. After elimination of water and sulfinic acid the pyrrolecarboxylate 9 is obtained which, on N‐alkylation with ethyl acrylate, Dieckmann cyclization, saponification and decarboxylation, yields methylloroquine 12. The reaction with chlorotrimethylsilane/sulfuric acid in acetic anhydride and subsequent saponification give loroquine (4) in 2.1% overall yield.
Epoxides of Phytosphingosine and Derivatives, Potential Inhibitors of Sphingosine Biosynthesis
Authors: Birk Rolf , Sandhoff Konrad , Schmidt Richard R. 
Published: July 2007

Abstract2,4‐O‐Benzylidene‐D‐threose (1) was treated with the Grignard reagent obtained from n‐octyl bromide to afford the epimeric tetrol derivatives 3a, b. Regioselective 2‐O‐mesylation and subsequent azido group introduction furnished azidophytosphingosine derivatives 5a, b. Ensuing 4‐O‐mesylation, acidcatalyzed benzylidene group removal and then treatment with NaH as a base provided preferentially the desired 3,4‐epoxide derivatives 8a, b; subsequent azido group reduction with triphenylphosphane/water yielded the target molecules 9a, b possessing D‐ribo and L‐lyxo configuration, respectively.
Stereoselective Synthesis of Alcohols, XLII. Stereoselective Cyclization of (8‐Oxo‐2‐octenyl)boronates to cis‐ or trans‐2‐Vinylcyclohexanol
Authors: Hoffmann Reinhard W. , Sander Thomas , Hense Achim 
Published: July 2007

AbstractIntramolecular allylboration reactions of (8‐oxo‐2‐octenyl)boronates proceed with excellent diastereoselectivity: the E‐isomer 1d leads to the trans‐2‐vinylcyclohexanol (2) with 99.5% d.s., the corresponding Z‐isomer 3d cyclizes to give the cis‐isomer with a diastereoselectivity exceeding 99.8%.
Acetogenic Isoquinoline Alkaloids, L. The Synthesis of All Possible Isomeric 6,8‐Dioxygenated 1,3‐Dimethyl‐1,2,3,4‐tetrahydroisoquinoline Methyl Ethers – Useful Chiral Building Blocks for Naphthylisoquinoline Alkaloids
Authors: Bringmann Gerhard , Weirich Ralf , Reuscher Hehnut , Jansen Johannes R. , Kinzinger Lioba , Ortmann Thomas 
Published: July 2007

AbstractThe practicable synthesis of all imaginable isomeric heterocyclic moieties 8–11 and ent‐8–ent‐11 of the naphthylisoquinoline alkaloids is described. The stereoinformation at C‐3 is induced by asymmetric reductive amination, using 1‐phenylethylamines of either enantiomeric series as chiral auxiliaries. The key step of the stereocontrolled construction of the stereocenter at C‐1 is the diastereoselective reduction of the corresponding dihydroisoquinolines, as obtained by Bischler‐Napieralski synthesis, or the regio‐ and stereoselective Pictet‐Spengler reaction of arylisopropylamines with acetaldehyde, respectively.