bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photochemistry of α‐oxo oximes. Part 11: Photochemical E‐Z isomerization of two 2‐(methoxyimino)‐1‐indanones. Evidence for excimer formation upon direct excitation at λ 300 nm
Authors: Buys Theo S. V. , Cerfontain Hans , Geenevasen Jan A. J. 
Published: September 2010

AbstractPhotochemical E‐Z isomerization of 2‐(methoxyimino)‐1‐indanone (1) and its 7‐methyl derivative (2) was studied under conditions of direct irradiation (λ 350 and 300 nm) and triplet photosensitization. The decay ratios k5/k6 for triplet photosensitization and direct irradiation at λ 350 nm are the same for a given compound, indicating that isomerization of the studied α‐oxo oxime ethers upon direct irradiation at λ 350 nm also proceeds from the (lowest) excited triplet state. Upon direct irradiation at λ 300 nm, the photostationary state (pss) was found to depend on the concentration of the 2‐(methoxyimino)‐1‐indanone: at high concentrations, the (E)‐isomer strongly dominates (>90%), whereas, at low α‐oxo oxime ether concentrations, a substantial amount of the (Z)‐isomer is present (up to 35%). The concentration dependence of the pss is explained in terms of excimer formation of the S2(ππ*) state, the excimer being capable of inducing efficient E‐Z isomerization with a different decay ratio than that of the excited triplet monomer.
Gas‐phase reactions of benzene and derivatives triggered by hydrazine/ozone; hydroxylation vs. degradation
Authors: Sol Veronica M. , Mulder Peter , Louw Robert 
Published: September 2010

AbstractThe reactions of benzene derivatives C6H5X (X = H, Cl, CH3 and CF3) with hydrazine and ozone in the dark (a source of OH radicals) have been studied in a flow reactor at ambient temperature.(Substituted) phenols were formed, but these were relatively unimportant compared to N‐heterocyclic compounds (condensation products of cis‐butenedial and analogues with hydrazine) and other (degradation) products.Benzene and (trifluoromethyl)benzene follow a similar path as toluene, also with oxidative ring opening as major reactions.
He I and He II photoelectron spectra and semi‐empirical calculations on the three geometric isomers of 3,3,4,4‐tetramethyl‐1,2‐bis(methoxyimino)cyclobutane
Authors: Stunnenberg Frank , Cerfontain Hans , Terpstra Andries 
Published: September 2010

AbstractThe experimental (PES) and calculated (MNDO) ionization potentials of the three geometric isomers of 3,3,4,4‐tetramethyl‐1,2‐bis(methoxyimino)cyclobutane [E,E)‐, (E,Z)‐ and (Z,Z)‐1] are reported. The derived electronic structures are compared with those of the three isomeric five‐membered ring homologues 2. The three different orientations of the two methoxy groups in 1 have only a small effect on the energy of the π levels since the three isomers of 1 are planar [or, as in the (Z, Z)‐isomer, almost so], but they have a significant effect on the order of the n+ and n− levels. The variations in the lone‐pair order are discussed in terms of through‐bond and through‐space interactions.
Controlled hydrolysis, an important side reaction in phosphazene chemistry
Authors: Brandt Krystina , van de Grampel Johan C. , Meetsma Auke , Jekel Andries P. 
Published: September 2010

AbstractReaction of (NPCl2)3 (1) with the monosodium salt of uracil in the presence of Bu4NBr as phase‐transfer catalyst gives apart from an uracil phosphazene derivative (N3P3Cl5)2C4N2H2O2 (2) appreciable amounts of two hydrolysis products, viz. [N3P3Cl5O] [Bu4N] (3) and an oxygen‐bridged dimer (N3P3Cl5)2O (4). 31P NMR data are given as well as the X‐ray structure of 4.
Photochemistry and spectroscopy of three α‐oxo oxime ethers: 4‐(methoxyimino)‐2,2,3,3‐tetramethylcyclobutanone, 3,3,5‐trimethyl‐4(5H)‐isoxazolone and 6‐(benzyloxyimino)‐2,2,5,5‐tetramethylcyclohexanone
Authors: Stunnenberg Frank , Cerfontain Hans , Geenevasen Jan A. J. , Hielkema Wim 
Published: September 2010

AbstractFollowing our previous reports on the spectroscopy and photochemistry of methyl and ethyl ethers of simple acyclic and non‐strained cyclic α‐oxo oximes, we have now studied 4‐(methoxyimino)‐2,2,3,3‐tetramethylcyclobutanone (1), of which the ring is severely strained, 3,5,5‐trimethyl‐4(5H)‐isoxazolone (8), of which the (Z)‐oxime function is constrained in a five‐membered ring, and 6‐(benzyloxyimino)‐2,2,5,5‐tetramethylcyclohexanone (10), which is a benzyl ether. Upon irradiation of (E)‐1 with λ 254 nm, the main process is photodissociation, leading to the same type of products as obtained with the six‐membered ring homologue 3, but in addition to 2,2,3,3‐tetramethyl‐4‐oxobutanenitrile (13) and 2,2,3,3‐tetramethylcyclopropanone O‐methyloxime (21). The triplet‐sensitized irradiation of (E)‐l, in contrast to that of the higher homologues, leads, in addition to E‐Z isomerization, to photodissociation, yielding the same photoproducts as obtained after direct irradiation with 254 nm.The 4‐isoxazolone 8 is photostable against radiation of 350 and 300 nm. Irradiation of 8 with λ. 254 nm leads to population of the excited singlet ππ* state and subsequent photodecomposition as a result of inital N‐O homolysis, the observed products being carbon monoxide, acetonitrile, acetone and small amounts of ethanol. The occurrence of the photodecomposition is in agreement with the theoretical prediction' that the excited singlet ππ* (Z)‐α‐oxo oxime ethers would give N‐O homolysis, provided that the other route of deactivation via Z‐E isomerization, which has a much lower energy barrier on the potential energy surface, cannot take place.The photochemistry of the benzyl ether (Z)‐10, of which the intercarbonyl‐iminyl dihedral angle is approx. 45° and the π systems of the phenyl and the C = N‐O moieties are perpendicular to one another, with λ 350, 300 and 254 nm is different from that of the corresponding methyl ether 36 in two ways. Firstly, on using λ 350 and 300 nm decomposition was observed which is, however, slow relative to the Z‐E isomerization and, secondly, the photodecomposition products are of a different nature, since the assigned primary and secondary product from 10 are benzaldehyde and 6‐(benzoylamino)‐2,2,5,5‐tetramethylcyclohexanone (32), respectively.Mechanisms have been presented to explain the formation of the photoproducts obtained from 1, 8 and 10.
Synthesis of potential UDP‐glucuronosyltransferase inhibitors containing a diphosphate function
Authors: Noort D. , van der Marel G. A. , van der Gen A. , J. H.  , Mulder G. J. 
Published: September 2010

AbstractThe synthesis of potential inhibitors of UDP‐glucuronosyltransferase, in which the β‐phosphate moiety of uridine 5′‐diphosphate is linked to phenolic or alcoholic hydroxyl groups, is described. Key intermediates in the formation of the diphosphate function are S‐(4‐methylphenyl) 2‐cyanoethyl phosphorothioate triesters which, after conversion into the corresponding S‐(4‐methylphenyl) phosphorothioate diesters, react with phosphate monoesters, in the presence of iodine, to give the target molecules.
Acylium salts: Synthesis of tris(3,4,5,6‐tetrahydro‐1,3,5‐triazinium) and tris(1,3,5‐oxadiazinium) salts
Authors: Tashtoush Hasan , Al‐Talib Mahmoud 
Published: September 2010

AbstractTriacylium salts 5 reacted with nine equivalents of dialkylcarbodiimide to give substituted tris(3,4,5,6‐tetrahydro‐1,3,5‐triazinium) salts 6a‐e. However, triacylium salts 5 reacted with six equivalents of N,N‐dialkylcyanamide to give amino‐substituted tris(1,3,5‐oxadiazinium) salts 7a‐e.
1H‐ and 13C‐NMR spectroscopy of synthetic monosulfated methyl α‐D‐mannopyranosides
Authors: Contreras Raphael Ruiz , Kamerling Johannis P. , Vliegenthart Johannes F. G. 
Published: September 2010

AbstractThe syntheses of methyl α‐D‐mannopyranoside 2‐, 3‐, 4‐, and 6‐(sodium monosulfate) are presented. The various monosulfated methyl α‐D‐mannopyranosides have been studied by 1H‐ and 13C‐NMR spectroscopy, affording insight into the 1H‐ and 13C‐shift effects caused by sulfation at particular positions. The NMR parameters of these sulfated monosaccharide derivatives are important, for example, in the structural analysis of sulfated carbohydrate chains of N‐glycoproteins.
An approach toward the synthesis of racemic myo‐inositol 1‐([S] 3,4‐di‐palmitoyloxybutyl)‐sulfonate
Authors: Elie C. J. J. , Dreef C. E. , Brounts D. M. , van der Marel G. A. , van Boom J. H. 
Published: September 2010

AbstractSubstitution of the triflate function in 1,2‐isopropylidene‐sn‐glycerol 3‐trifluoromethanesulfonate by the α‐lithio‐anion of 2,3,4,5,6‐penta‐O‐benzyl‐myo‐inositol 1‐methanesulfonate afforded, after acid hydrolysis of the acetonide function, followed by palmitoylation and removal of the benzyl groups, the racemic and isosteric methylenesulfonyl analogue IV of phosphatidyl‐D‐myo‐inositol.
Catalytic hydrogenation of D‐xylo‐5‐hexulosonic acid to gluconic and idonic acid
Authors: Caldeira M. M. , Wurtz E. , Peters J. A. , van Bekkum H. 
Published: September 2010

AbstractThe influence of the choice of catalyst and the presence of additives on the selectivity of the hydrogenation of D‐xylo‐5‐hexulosonic acid was investigated. Optimal amounts of idonic acid were obtained with palladium boride as the catalyst in aqueous solution at pH 9, 80 °C and 100 kg/cm2 H2. Under these conditions, the conversion is 100% and the molar ratio of idonic and gluconic acid in the reaction product is 3/1, whereas almost no side products (<5%) were formed.
Stereochemical aspects of the “tert‐amino effect”. Controlled cycloreversion of pyrrolo[1,2‐α]quinoline derivatives and enantioselective introduction of two new optically active centers
Authors: Kelderman E. , Noorlander‐Bunt H. G. , Verboom W. , Reinhoudt D. N. , van Eerden J. 
Published: September 2010

AbstractConversion of 2‐vinyl‐N,N‐dialkylanilines 2,3(a‐o) to pyrrolo[1,2‐α]quinolines 4–13 (a‐o) occurs via an irreversible suprafacial 1,5 hydrogen shift to a dipolar intermediate which subsequently cyclizes. In refluxing acetonitrile in the presence of zinc chloride, pyrrolo[1,2‐a]quinoline derivatives having two electron‐withdrawing groups (EWG) at C(4) show cycloreversion. Because of the longer lifetime of the stabilized dipolar intermediate, epimerization at C(4) and/or C(3a) can occur. Epimerization at C(3a) is prevented by a large methoxymethyl substituent at this stereocenter. Since the initial 1,5 hydrogen shift is irreversible, the stereochemistry at C(5) remains unchanged. In product 4j, two new optically centers at C(5) and C(4) were introduced in a controlled manner and at C(3a) “self‐reproduction of chirality” was obtained without the use of auxiliary chiral reagents.
Formation of pentafulvene in flash vacuum thermolysis of 5‐[7‐(2‐norbornenylidene)] meldrum's acid over bituminous carbon: Evidence for cyclopentadienylidene carbene
Authors: Wiersum Ulfert E. , Jenneskens Leonardus W. 
Published: September 2010

AbstractThe formation of pentafulvene (12)and benzene (11) upon flash vacuum thermolysis of 5‐[7‐(2‐norbornenylidene)] Meldrum's acid (9) over a hydrogen donating bituminous carbon matrix, provides the first experimental evidence for the occurrence of cyclopentadienylidene carbene (2) as a discrete species on the C6H4. energy surface.
A new synthetic methodology for 1,3‐diynes
Authors: Brandsma L. , Verkruijsse H. D. , Fossatelli M. 
Published: September 2010

Abstract1,3‐Diyne derivatives, (3) and related highly unsaturated compounds have been obtained with excellent overall yields by functionalization of the readily available 1‐ethylthio‐1,3‐butenyne (1) followed by reaction of the derivatives (2) with sodamide in liquid ammonia.
Reversible carbonylation of cationic palladium 2,6‐bis[(dimethylamino)methyl]pyridine complexes: The first X‐ray structure of a cationic aroyl‐palladium complex
Authors: Markies Bertus A. , Wijkens Peter , Boersma Jaap , van Koten Gerard , Spek Anthony L. 
Published: September 2010

Abstract(1‐Naphthyl)(2,6‐bis[(dimethylamino)methyl]pyridine}palladium(II) trifluoromethanesulphonate (1b, [Pd(1‐C10H7)(NN′N)]OTf) was prepared in 60% yield starting from bis(dibenzylideneacetone)palladium(0) (Pd(dba)2) and 1‐iodonaphthalene. (1‐Naphthoyl){2,6‐bis[(dimethylamino)methyl]pyridine}palladium(II) trifluoromethanesulphonate (2b, [Pd(C(O)‐1‐C10H7)(NN′N)]OTf), characterized by X‐ray crystallography, was obtained by insertion of carbon monoxide into the palladium‐carbon bond of lb in acetone solution. This insertion process was shown to be reversible.
Chemo‐enzymatic synthesis of specifically stable‐isotope labelledL‐glutamic acid and 2‐oxoglutaric acid
Authors: Cappon J. J. , Baart J. , van der Walk G. A. M. , Raap J. , Lugtenburg J. 
Published: September 2010

Abstract(3‐13C)‐, (4‐13C)‐, (5‐13C) and (3,4‐13C2)‐2‐oxoglutaric acid were prepared starting from the simple 13C‐enriched compounds: ethyl bromoacetate and paraformaldehyde, via a single reaction scheme on the gram scale in high yield. This reaction scheme allows specific 13C enrichment of every carbon position and any combination of positions. (3‐13C)‐, (4‐13C)‐, (5‐13C), (3,4‐13C2) and (15N)‐L‐glutamic acid were prepared by converting the corresponding 2‐oxoglutaric acids via an enantioselective enzymatic conversion. The labelled L‐glutamic acids and 2‐oxoglutaric acids were characterized by 1HNMR, 13CNMR and mass spectrometry.
Acceleration of enzyme‐catalyzed reactions in organic solvents by crown ethers
Authors: Broos Jaap , Martin Marie‐Noëlle , Rouwenhor Inge , Verboom Willem , Reinhoudt David N. 
Published: September 2010

AbstractCrown ethers can strongly enhance the transesterification of N‐acetyl‐1‐phenylalanine ethyl ester with 1‐propanol catalyzed by α‐chymotrypsin in various organic solvents. Of the different crown ethers tested, 18‐C‐6 gave the best results. It was found that a macrocyclic effect is responsible for the observed rate enhancement. It is proposed that the water‐ and cation‐complexing ability of crown ethers plays a key role in the observed rate enhancement.
Nucleophilic substitution in diphenylmethyl derivatives. II. Methanolysis of α substituents of diphenylacetic acid and its derivatives
Authors: Strazzolini Paolo , Poiana Marco , Verardo Giancarlo , Giumanini Angelo G. 
Published: September 2010

AbstractThe nucleophilic displacement of α substituents of diphenylacetic acid and its methyl ester by MeOH under a variety of experimental conditions allowed us to establish that the reaction occurs rapidly in one of the following structural combinations: (a) carboxylate anion and a good leaving group; (b) carboxylic group and a less reactive leaving group; (c) methyl ester and proton‐activated, poor leaving group. The importance of internal hydrogen bonding (case b) was the governing factor in the outcome of the reaction of hydroxydiphenylacetic acid (3a) and its methyl ester 3b with acetyl chloride. The key intermediate in substitution at the α carbon is thought to be a carbocation stabilized both by the attached phenyl groups and, to a smaller extent, by the carboxyl group.
The influence of substituents on the geometry of the cyclopropane ring. V. The molecular and crystal structure of 1‐amino‐1‐methylcyclopropane
Authors: de Boer J. S. A. M. , Stam C. H. 
Published: September 2010

AbstractCrystals of 1‐amino‐1‐methylcyclopropane, C4H9N, grown from the liquid, are tetragonal, space group I41/a, a = 18.142(3), c = 5.882(1) Å, (169K), Z = 16. The final R for 733 independent observed reflections is 0.040. The molecule has the s‐trans pyramidal conformation for the amino group. The bond‐length asymmetry induced by the substituents is small and about equal to that in aminocyclopropane. The average CC bond length is 1.513 Å (corrected for libration).
A study on the use of phenylacetyl disulfide in the solid‐phase synthesis of oligodeoxynucleoside phosphorothioates
Authors: Roelen H. C. P. F. , Kamer P. C. J. , van den Elst H. , van der Marel G. A. , van Boom J. H. 
Published: September 2010

AbstractSulfurization of protected [i.e., 2‐cyanoethyl, methyl and 2‐(4‐nitrophenyl)ethyl] internucleosidic phosphite triesters can be conveniently executed with the easily accessible reagent, phenylacetyl disulfide (1). High‐quality oligodeoxynucleotides containing predetermined combinations of natural and phosphorothioate linkages can be obtained via a solid‐phase approach by using reagent 1 and 2‐(4‐nitrophenyl)ethyl‐protected phosphoramidites.
Formation of 1,2,4‐benzenetriol by hydrothermal treatment of carbohydrates
Authors: Luijkx G. C. A. , van Rantwijk F. , van Bekkum H. 
Published: September 2010

AbstractConversion of dilute aqueous solutions of 5‐hydroxymethyl‐2‐furaldehyde and D‐fructose under near‐critical conditions led to the formation of 1,2,4‐benzenetriol in relatively high yields.
The use of phosphorus oxychloride in the synthesis of amino acid p‐nitroanilides
Authors: Rijkers D. T. S. , Hemker H. C. , Nefkens G. H. L. , Tesser G. I. 
Published: September 2010

AbstractPhosphorus oxychloride is described as a condensing agent in the preparation of nitroanilides. The condensation was free of racemization with amino acid derivatives of the urethane type and the current amino protective groups can be applied. The yields are high to excellent.
Fluorescence of and photoinduced electron injection into the C70 fullerene chromophore
Authors: Verhoeven Jan W. , Scherer Taco , Heymann Dieter 
Published: September 2010

AbstractThe fluorescence of the C70 fullerene chromophore in three solvents is reported. Quenching of this fluorescence by organic electron donors occurs as a result of photoinduced electron transfer. With aniline‐type donors ground‐state charge transfer complex formation is evident from curved Stern‐Volmer plots as well as from additional long wavelength absorption.
Cation exchange in the system CaII or MgII + complexing‐agent + zeolite‐NaA: Equilibria in water‐ethanol
Authors: Ebaid A. R. , Barakat A. K. , Khalifa N. A. , Kandil A. T. , Maesen Th. L. M. , van Bekkum H. 
Published: September 2010

AbstractThe ion‐exchange behaviour of CaII and MgII with zeolite NaA in ethanol‐water systems has been studied. The ion‐exchange isotherms show that the affinity of the zeolite for CaII and MgII ions decreases with increasing ethanol content, i.e. decreasing dielectric constant of the media. When adding nitrilotriacetate (NTA) as a complexing agent, the selectivity of zeolitic NaA for CaII and MgII ions was found to decrease. The exchange phenomena observed are discussed in relation with water distribution and cation coordination preferences. Cation‐anion coordination in mixed solvents was studied using 35Cl NMR.
Fluorescence spectroscopic study of the formation of hydrophobic microdomains in aqueous solutions of poly(alkylmethyldiallylammonium bromides)
Authors: Yang Ya Jiang , Engberts Jan B. F. N. 
Published: September 2010

AbstractThe conformational state of poly(alkylmethyldiallylammonium bromides) was studied in aqueous solutions using pyrene as a fluorescence probe. The results are indicative for the formation of hydrophobic microdomains in the case of several copolymers which possess sufficiently hydrophobic alkyl side chains. For these materials the polymer main chain is flexible enough to form a compact‐coil conformation which allows intramolecular micellization. The effect of temperature and of the addition of NaBr and DMSO on microdomain formation was briefly investigated.
Studies on the conversion of 3,3‐dimethyl‐2‐butanone into geminal isocyano tosyl alkenes
Authors: van Leusen Daan , van Leusen Albert M. 
Published: September 2010

Abstract3,3‐Dimethyl‐2‐butanone (pinacolone) was converted in a two‐pot, three‐step process in 67% overall yield into (E)‐1‐isocyano‐2,3,3‐trimethyl‐1‐tosyl‐1‐butene (1), or 1‐isocyano‐3,3‐dimethyl‐2‐methylene‐l‐tosylbutan(2), as an important departure from the previously reported one‐pot conversion to 2,3,3‐trimethylbutanenitrile (13). In addition, the synthesis procedure for 13 has been improved.
An alternative synthesis of (+)‐sesbanimide A
Authors: Vloon W. J. , van Den Bos J. C. , Willard N. P. , Koomen G.‐J. , Pandit U. K. 
Published: September 2010

AbstractD‐(+)‐xylose has been converted to (+)‐sesbanimide A in sixteen steps. The synthetic scheme involves an unusual tricyclic silylated derivative (9a) of the monobenzoylated product of the earlier described glutarimide intermediate (7). Compound 9a is a pivotal intermediate for the construction of ring C of (+)‐sesbanimide A.
Regioselective synthesis of nucleopeptidic bioconjugates enzymatic catalysis with ultrasonic irradiation
Authors: Criton Marc , Dewynter Georges , Montero Jean‐Louis 
Published: September 2010

AbstractThe regioselective acylation of adenosine by phenylalanine was carried out using subtilisin in reverse mode. Under ultrasonic irradiation, the bioconversion affords only the S' aminoester.
Synthesis of (3′→5′) methylene acetal linked dinucleosides containing cytosine bases
Authors: Quaedflieg P. J. L. M. , van der Marel G. A. , Kuyl‐Yeheskiely E. , van Boom J. H. 
Published: September 2010

Abstract5′‐O‐Methoxyacetyl‐3′‐O‐methylthiomethylene‐2′‐deoxy‐uridine could be condensed with 3′‐O,N3‐di‐benzoyl‐thymidine using NIS I cat. TfOH as the activating system, to give the (3′→ 5′) methylene acetal linked dinucleoside. After removal of the methoxyacetyl group and tritylation of the 5′‐hydroxyl function, the uridine moiety was converted into cytidine via the corresponding 4‐triazolo analogue. Subsequent N4‐benzoylation of cytidine and phosphitylation of the 3′‐terminus afforded the fully protected d(C∧T) phosphoramidite dimer 9.
New developments in thermally stable polymers
Authors: Hergenrother Paul M. 
Published: September 2010

AbstractAdvances in high‐temperature polymers since 1985 are discussed with the emphasis on the chemistry. High‐temperature polymers refer to materials that exhibit glass‐transition temperatures > 200°C and have the chemical structure expected to provide high thermooxidative stability. Specific polymers or series of polymers were selected to show how the chemical structure influences certain properties. Poly(arylene ethers) and polyimides are the two principal families of polymers discussed. Recent work on poly(arylene ethers) has concentrated on incorporating heterocyclic units within the polymer backbone. Recent polyimide work has centered on the synthesis of new polymers from novel monomers, several containing the trifluoromethyl group strategically located on the molecule. Various members in each of these polymer families display a unique combination of properties, heretofore unattainable. Other families of polymers are also briefly discussed with a polymer from an AB maleimidobenzocyclobutene exhibiting an especially attractive combination of properties.
Synthesis of functionalized phenylalanine derivatives by ring opening reactions of 3‐arylaziridine‐2‐carboxylic esters
Authors: Legters Johan , Thijs Lambertus , Zwanenburg Binne 
Published: September 2010

AbstractRing‐opening reactions of 3‐arylaziridine‐2‐carboxylic esters with various nucleophiles are described. Racemic methyl 3‐(4‐methoxyphenyl)‐, 3‐phenyl‐ and 3‐(4‐nitrophenyl)aziridine‐2‐carboxylate (1a, 1b and 1c, respectively) were selected as substrates. In the absence of acid, no ring opening occurred. On treatment with ethereal hydrogen chloride, 1a gave a mixture of diastereomers 2a, whereas 1b and 1c gave mixtures of regioisomers 2b/3b and 2c/3c, respectively. Boron‐trifluoride etherate catalyzed reaction of 1a with benzenethiol and indole also resulted in the formation of diastereomeric ring‐opened products 4a and 6a, respectively, due to the electron‐releasing properties of the p‐methoxy group. Only C3 attack was observed. Under the same conditions, 1b and 1c gave a clean SN2‐type ring opening, leading to diastereomerically pure products 4b, 4c, 6b and 6c. Reaction of 1b with acetic acid gave 7 in an SN2‐type ring opening at C3, followed by an O→N acyl shift. Treatment of enantiopure (+ )‐(2S,3R)‐1b with benzenethiol, indole and acetic acid gave the corresponding enantiomerically pure β‐functionalized α‐amino acid derivatives. Functionalization of 1b at nitrogen strongly increased the reactivity: N‐acylaziridine 8 isomerized to trans‐oxazoline 11 when treated with boron trifluoride etherate in acetonitrile.