A practical synthesis of optically active aromatic epoxides via asymmetric transfer hydrogenation of α-chlorinated ketones with chiral rhodium–diamine catalyst
A practical method for the synthesis of optically active aromatic epoxides has been developed via the formation of optically active α-chlorinated alcohols and intramolecular etherification. Optically active alcohols with up to 99% ee can be obtained from the asymmetric reduction of aromaticketones with a substrate/catalyst ratio of 1000–5000 using a formic acid/triethylamine mixture containing a well-defined
Highly enantioselective acylation of chlorohydrins using Amano AK lipase from P. fluorescens immobilized on silk fibroin–alginate spheres
作者:Irlon M. Ferreira、Rodolfo H.V. Nishimura、Ana B. dos A. Souza、Giuliano C. Clososki、Sergio A. Yoshioka、André L.M. Porto
DOI:10.1016/j.tetlet.2014.07.032
日期:2014.9
kinetic resolution mediated by Amano AK lipase from Pseudomonasfluorescens immobilized in silk friboin-alginate spheres. Thus, the enantioselectivity of the process was sufficient for the production of the desired alcohols and acetates in good yields and high enantiomeric purities. This Letter provides a simple, cheap, and practical protocol for enantioselective synthesis of chlorohydrins and reinforces
Enzymatic Resolution of Chlorohydrins for the Synthesis of Enantiomerically Enriched 2-Vinyloxiranes
作者:Mark Lautens、J. McCubbin、Matthew Maddess
DOI:10.1055/s-2007-1000845
日期:2008.1
A series of vinylchlorohydrins are resolved by enzymatic kinetic resolution. The resulting R-alcohols, obtained in up to 99% ee, are stereoselectively converted into vinyloxiranes in high yield. The S-acetates, obtained in up to 99% ee were either deprotected to S-alcohols, or cyclized directly to vinyl oxiranes under basic conditions, with moderate to no loss in ee. The results are consistent with
通过酶动力学拆分来拆分一系列乙烯基氯醇。所得的 R-醇以高达 99% 的 ee 获得,以高产率立体选择性地转化为乙烯基环氧乙烷。以高达 99% ee 获得的 S-乙酸酯要么脱保护为 S-醇,要么在碱性条件下直接环化为乙烯基环氧乙烷,ee 中度至无损失。结果与涉及脱保护过程中醋酸盐可逆迁移的外消旋化机制一致。