1-DEOXY-D-XYLULOSE SYNTHESIZED FROM THE (S)-CYANOHYDRIN OF ACROLEIN
摘要:
The biocatalytic transformation of acrolein into (S)-2-hydroxybut-3-enenitrile using the (S)-hydroxynitrile lyase from Hevea brasiliensis followed by Grignard C-elongation, asymmetric epoxidation and nucleophilic ring-opening afforded 1-deoxy-D-xylulose (1) in 47% overall yield.
The enantioselective addition of trimethylsilyl cyanide to a variety of aldehydes proceeded by the aid of a catalyst prepared in situ from titanium tetraisopropoxide [Ti(O-i-Pr)4] and chiral Schiff bases and gave the corresponding cyanohydrins in high optical yield (up to 96% e.e.). A remarkable rate enhancement was brought about by the addition of the Schiffbase to the titanium alkoxide mediated
Enzyme catalysed formation of (S)-cyanohydrins derived from aldehydes and ketones in a biphasic solvent system
作者:Herfried Griengl、Norbert Klempier、Peter Pöchlauer、Michael Schmidt、Nongyuan Shi、Antonina A Zabelinskaja-Mackova
DOI:10.1016/s0040-4020(98)00901-6
日期:1998.11
By employing a vigorously stirred two phase system aqueous buffer/organic solvent and using the hydroxynitrilelyase from Hevea brasiliensis as biocatalyst enantiopure (S)-cyanohydrins from aliphatic, unsaturated, aromatic and heteroaromatic aldehydes and methyl alkyl and methyl phenyl ketones are obtained in high yield and in general 98–99% enantiomeric excess.
α,β-unsaturated (S)-cyanohydrins derived from 2-propenal, 2-butenal, (E) and (Z)-2-hexenal and 2-hexynal are obtained in high enantiomeric purity (80–95% e.e.) by using an oxynitrilase isolated from the leaves of Hevea brasiliensis.
A variety of aldehydes (aromatic, heteroaromatic, alpha,beta-unsaturated, and nonconjugate aliphatic aldehydes) has been trimethylsilylcyanated in highly enantiomeric excess (ee) with a catalyst prepared in situ from titanium tetraisopropoxide [Ti(O-i-Pr)4] and chiral Schiff bases. A remarkable rate enhancement was brought about by the addition of the Schiff base into the titanium alkoxide mediated silylcyanation of aldehydes. The chemical structure of chiral Schiff base-titanium alkoxide complexes is discussed based on their C-13 NMR spectra, field desorption (FD) mass spectra, and molecular weights.
Aliphatic (S)-cyanohydrins by enzyme catalyzed synthesis
The enzyme catalyzed synthesis of aliphatic (S)-cyanohydrins has been accomplished for the first time by application of a hydroxynitrile lyase from leaves of Hevea brasiliensis. The optical purities of (S)-cyanohydrins are in a range between 60-97%.