Continuous recycling of the minor product enantiomer obtained from the acetylcyanation of prochiral aldehydes provided access to highly enantiomerically enriched products. Cyanohydrin derivatives, which under normal conditions are obtained with modest or poor enantiomeric ratios, were formed with high enantiomeric purity by using a reinforcing combination of a chiral Lewis acid catalyst and a biocatalyst
Asymmetric Hydrogenation of α-Primary and Secondary Amino Ketones: Efficient Asymmetric Syntheses of (−)-Arbutamine and (−)-Denopamine
作者:Gao Shang、Duan Liu、Scott E. Allen、Qin Yang、Xumu Zhang
DOI:10.1002/chem.200700594
日期:2007.9.17
Two beta-receptor agonists (-)-denopamine and (-)-arbutamine were prepared in good yields and enantioselectivities by asymmetrichydrogenation of unprotected aminoketones for the first time by using Rh catalysts bearing electron-donating phosphine ligands. A series of alpha-primary and secondaryaminoketones were synthesized and hydrogenated to produce various 1,2-amino alcohols in good yields and
Asymmetric synthesis of alpha-substituted-alpha-cyanomethyl alcohols
申请人:ICI AUSTRALIA LIMITED
公开号:EP0132392A2
公开(公告)日:1985-01-30
The invention concerns a process for the preparation of an a-substituted-a-cyanomethyl alcohol enantiomer of formula 1
wherein the group R1 is an alkenyl, alkynyl, aryl or heteroaryl group by reacting an aldehyde of formula II
with hydrogen cyanide in the presence of a cyclic dipeptide enantiomer at a temperature below ambient temperature.
The process enables the preparation of compounds of formula I in high yield and high enantiomeric excess. The enantiomers of formula I may be used as intermediates fortheprepara- tion of chiral pyrethroids and chiral arylethanolamines.
The invention also embraces cyclic dipeptide enantiomers, processes for the preparation of chiral pyrethroids and chiral arylethanolamines from a-substituted-a-cyanomethyl alcohol enantiomers of formula I and chiral pyrethroids and chiral ethanolamines and the chiral pyrethroids and chiral ethanolamines prepared thereby.
本发明涉及一种制备式 1 的 a-取代-a-氰基甲醇对映体的工艺,其中基团 R1 是烯基、炔基、芳基或杂芳基。
其中基团 R1 为烯基、炔基、芳基或杂芳基。
在低于环境温度的条件下,在环状二肽对映体存在的情况下,使式 II 的醛与氰化氢反应。
该工艺可制备高产率和高对映体过量的式 I 化合物。式 I 的对映体可用作制备手性拟除虫菊酯和手性芳基乙醇胺的中间体。
本发明还包括环二肽对映体、从式 I 的 a-取代-a-氰基甲醇对映体制备手性拟除虫菊酯和手性芳基乙醇胺的工艺、手性拟除虫菊酯和手性乙醇胺以及由此制备的手性拟除虫菊酯和手性乙醇胺。
JACKSON, WILLIAM ROY;MATTHEWS, BARRY ROSS;WILSHIRE, COLIN
作者:JACKSON, WILLIAM ROY、MATTHEWS, BARRY ROSS、WILSHIRE, COLIN