prepared in one step were reduced using baker'syeast to afford 1-chloro-2-hydroxy-4-alkanones 2a–f regioselectively in S 29% to R 58% ee. Use of a small amount of organic solvents to dissolve the substrate enhanced the enantiomeric excess in favor of the S configuration. The function of the organic solvents was studied with reducing enzymes isolated from baker'syeast. Some polar solvents selectively inhibited
Synthesis and Reactions of Optically Active 1,3-Diols
作者:Lukas Rösslein、Christoph Tamm
DOI:10.1002/hlca.19880710106
日期:1988.2.3
available in (R)- and (S)-configuration. Octyl (3R)-4-chloro-3-hydroxybutanoate (17) is an alternative starting material for the preparation of 5 (Scheme 3.) The epoxide 20, derived from 5 in a one-pot reaction, is a versatile synthon, which selectively reacts with a great number of nucleophiles (Scheme 4).
Bakers' yeastreduction of 1-chloro-2,4-alkanediones 1a afforded 1-chloro-2-hydroxy-4-alkanones 2a regioselectively with low opticalpurities. Application of inhibitors and heat-treatment of bakers' yeast enhanced the opticalpurities toward the S enantiomer (88–91% ee). Organic solvents added in small amounts were also found to enhance the S selectivity significantly. Highopticalpurities of 94–96%
Process for the Synthesis of Hmg-Coa Reductase Inhibitors
申请人:Casar Zdenko
公开号:US20080300406A1
公开(公告)日:2008-12-04
A novel synthesis of statins uses Wittig reaction of a heterocyclic core of statin with a lactonized side chain already possessing needed stereochemistry. Any separation of diastereoisomers is performed early in the course of synthesis.