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
Hydroxynitrile lyases (HNLs) catalyze the enantioselective cleavage/formation of cyanohydrins. However, current methods for determining hydrocyanation are not suitable for mass screening of mutants for protein engineering of these biocatalysts. We demonstrate herein a chromogenic high‐throughput screening method for cyanohydrinsynthesis that is validated by either substrate profiling or the directed evolution
BMPD, a novel C2-chiral 1,3-diketone ligand; synthesis and application to an asymmetric catalytic reaction
作者:Atsushi Abiko、Guo-qiang Wang
DOI:10.1016/s0040-4020(98)00695-4
日期:1998.9
complexation ability of BMPD. A BMPD-yttrium complex was found to act as a new catalyst for silylcyanation of aldehydes with remarkable efficiency. As little as 0.2 mol% of the complex catalyzed the reaction of benzaldehyde and cyanotrimethylsilane to afford the cyanohydrin in 95% yield with 87% ee.
The vanadium(V)(salalen) complex prepared in situ from the corresponding vanadium(IV) complex 4 under aerobic conditions was found to be an excellent catalyst for asymmetric transcyanation of aliph...
A new (R)-hydroxynitrile lyase from Prunus mume: asymmetric synthesis of cyanohydrins
作者:Samik Nanda、Yasuo Kato、Yasuhisa Asano
DOI:10.1016/j.tet.2005.08.105
日期:2005.11
A new hydroxynitrile lyase (HNL) was isolated from the seed of Japanese apricot (Prunus mume). The enzyme has similar properties with HNL isolated from other Prunus species and is FAD containing enzyme. It accepts a large number of unnatural substrates (benzaldehyde and its variant) for the addition of HCN to produce the corresponding cyanohydrins in excellent optical and chemical yields. A new HPLC