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.
A Facile Synthesis of Optically Active γ-Cyanoallylic Alcohols Using Asymmetric Hydrocyanation of α,β-Alkenyl Aldehydes Followed by Stereospecific [3.3]Sigmatropic Chirality Transfer of the Cyanohydrin Acetates
Optically active γ-cyanoallylic alcohols were synthesized by using asymmetric hydrocyanation of α,β-alkenyl aldehydes catalyzed by peptide-titanium complex to give α-cyanoallylic alcohols (cyanohydrins) with high optical yields followed by palladium complex catalyzed [3.3]sigmatropic chirality transfer of the corresponding acetates.
A Chemoenzymatic Access to d- and l-Sphingosines Employing Hydroxynitrile Lyases
作者:Dean V. Johnson、Ulfried Felfer、Herfried Griengl
DOI:10.1016/s0040-4020(99)01024-8
日期:2000.1
A chemoenzymatic access to d- or l-sphingosines is presented comprising of a totalsynthesis of the l-threo-isomer and formal syntheses of the other three isomers. Key to the development of a general synthetic strategy has been the use of enantiocomplementary hydroxynitrile lyases (Hnls) to yield an enantiomeric pair of starting materials. The (S)-Hnl from Hevea brasiliensis has been used to prepare