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Pseudo-α-L-fucopyranose 1 and pseudo-6-deoxy-β-D-altropyranose 2 have been synthesised from ((5 S ,6 R )-5,6-dihydroxy-1,3-cyclohexadienyl)methanenitrile 3 .

The stereochemistry of the alkali-catalysed rearrangement of α-acetohydroxybutyrate (2-ethyl-2-hydroxy-3-oxobutanoate) was studied. The rearrangement was found to proceed via a transition state in which a syn arrangement of the C–O bonds is preferred over the anti arrangement by a factor of ≥2:1.

Pyruvate decarboxylase from Saccharomyces sp. catalysed the formation of acetoin of predominantly the opposite configuration than that obtained using the enzyme from Zymomonas mobilis. A similar result was obtained for the lactaldehyde formed in the pyruvate decarboxylase-catalysed decarboxylation of glyoxylate in the presence of acetaldehyde. The results are interpreted in terms of different Boltzmann distributions for the two enzymes between the enzyme–substrate complexes of acetaldehyde bound on its re and si faces respectively.

Dimethyl cis -2-cyclobutene-1,2-dicarboxylate 1 was kinetically resolved by porcine liver esterase to give methyl hydrogen (1 R , 2 S )- (+)- cis -3-cyclobutene-1,2-dicarboxylate 3 . ((1 R ,4 S )-4-Ethanoyloxymethyl-2-cyclobutenyl)methyl ethanoate 2 was kinetically resolved using the lipase from Pseudomonas fluorescens (Amano P) to give ((1 R ,4 S )-4-hydroxymethyl-2-cyclobutenyl)methyl ethanoate 8 .

A three-step synthesis of vinylglycine 1 has been developed using a readily available starting material (but-3-enenitrile 2), based on the Neber rearrangement of the corresponding N-chloroimidate, and using cheap, convenient reagents. Also described is a convenient optical resolution of the N-tert-butoxycarbonyl derivative by papain-catalysed enantioselective esterification in a two-phase system. From the optically active amino acid, related amino acids obtained via epoxidation, dihydroxylation and cyclopropanation have been prepared. The related β, γ-unsaturated amino acids (E)-2-aminopent-3-enoic acid 20 and (E)-2-amino-3-methylpent-3-enoic acid 22 have been synthesised using the same approach.

(1R, 2R, 3S, 4S)-1-Hydroxymethylcyclopentane-2,3,4-trio 2, a possible precursor of aristeromycin 1 was synthesised in tritiated form and administered to Streptomyces citricolor. Radioactivity was incorporated into aristeromycin, but degradation showed that incorporation of radioactivity was nonspecific, indicating that the tetrol 2 is not an immediate precursor of aristeromycin 1.

A six step synthesis of (−)-6-hydroxyshikimic acid 2 has been developed starting from ((5S, 6R)-5,6-dihydroxy-1,3-cyclohexadienyl)methanenitrile 3 , produced by biotransformation of cyanobenzene by the enzyme toluene dioxygenase.

Recombinant pyruvate decarboxylase from Zymomonas mobilis catalysed the formation of R-aromatic acyloins of high optical purity from aromatic aldehydes and either pyruvate or acetaldehyde. The results are contrasted with those obtained with aliphatic acyloins and compared with those obtained with the pyruvate decarboxylase of Saccharomyces sp.

Octyl oxalamic esters of 1-phenylethylamine and substituted 1-phenylethylamines are kinetically resolved with high stereoselectivity by lipase B from Candida antarctica.

Remarkable advances in glycobiology in recent years have stimulated a resurgence of interest in carbohydrate chemistry. The challenge of producing the complex glycosides and oligosaccharides needed for research in glycobiology has led to the development of enzymatic methods that are now firmly established as part of the synthetic repertoire of the carbohydrate chemist.

Pig liver esterase-catalysed hydrolysis of (±)-endo-2-methoxycarbonyl-7-oxabicyclo[2.2.1]hept-5-ene 1a provides (–)-endo-7-oxabicyclo[2.2.1]hept-5-ene-2-carboxylic acid 1b and (+)-endo-2-methoxycarbonyl-7-oxabicyclo[2.2.1]hept-5-ene 1a in 36 and 57% ee, respectively. Transesterification between (±)-2-exo-hydroxy-4,8-dioxatricyclo[4.2.1.03,7]nonan-5-one 2a and vinyl acetate catalysed by the lipase from Pseudomonas fragi gives the acetate (–)-2b and alcohol (+)-2a in 91 and 94% ee, respectively. Optically pure acetate (–)-2b is obtained after removal of contaminating racemate from the impure acetate by crystallisation of (–)-2b of 91% ee (EtOH).

The β-N-acetylhexosaminidase from Aspergillus oryzae and the β-mannosidases from Helix pomatia and A. oryzae were purified and used to synthesise the core trisaccharide of N-linked glycoproteins, Manp-(1→4)-β-D-GlcpNAc-(1→4)-D-GlcpNAc.

A novel chiral stationary phase consisting of poly-L-leucine supported on porous graphitic carbon has been shown to be effective in the separation of the enantiomers of epoxides 1-5 by chiral high performance liquid chromatography.

Thiolactosyl lipids designed for carbohydrate-protein binding studies have been synthesised. One representative was selected for binding studies with a plant lectin RCA120, the agglutinin from Ricinus communis. The interactions were measured quantitatively in real time using a BIAcore surface plasmon resonance instrument. Removal of much of the galactose from the thiolactosyl lipid in situ with beta-galactosidase showed that the lectin binding was highly specific. A dissociation constant KD = 8.77 x 10(-8) M was measured for 1-[2-[2-(2-[beta-D-galactopyranosyl-(1-->4)-1-thio-beta-D -glucopyranosyl]ethoxy)ethoxy]ethoxy]octadecane 30 which is four orders of magnitude greater than that determined for binding to lactose in solution. A concentration of lactose of > 80 mM was required to block the lectin binding to thiolactosyl lipid in a neomembrane.

Pyruvate and 2-oxobutanoate were incubated with acetolactate synthase [acetolactate pyruvate lyase (carboxylating, EC 4.1.3.18)] in the presence of acetolactate decarboxylase [(S)-2-hydroxy-2-methyl-3-oxobutanoate carboxy-lyase, EC 4.1.1.5)]. The exclusive production of 3-hydroxypentan-2-one showed that the α-acetohydroxybutyrate (2-ethyl-2-hydroxy-3-oxobutanoate) produced by acetolactate synthase had the (S)-configuration. The ability of acetolactate decarboxylase to catalyse rearrangement of the (R)-enantiomer of substrates via carboxylate migration was investigated using [3,4-13C2]-α-acetolactate, in which the degeneracy of the rearrangement of the normal substrate was broken by isotopic labelling. The predicted sequential formation of [1,2-13C2]- and [3,4-13C2]-acetoin was observed.

All four stereoisomers of methyl 6-(p-chlorophenylthio)-3,5-dihydroxyhexanoate have been synthesised by a route in which the key introduction of chirality was effected by an appropriate yeast reduction.