Desymmetrisation of (4R,5S)-4,5-diphenylimidazolidine-2-thione using pentafluorophenyl active esters
作者:Anna Andreou、Jason Eames、Majid Motevalli、Timothy J. Prior、Michael Watkinson
DOI:10.1016/j.tetlet.2010.01.019
日期:2010.3
(4R,5S)-4,5-Diphenylimidazolidine-2-thione is efficiently desymmetrised by stereorandom deprotonation with NaHMDS, followed by kinetic resolution of the resulting racemic intermediate with an enantiomerically pure pentafluorophenyl active ester. The levels of diastereocontrol were found to be excellent (86-92% de at similar to 30% conversion). This desymmetrisation reaction is an example of a masked resolution. (C) 2010 Elsevier Ltd. All rights reserved.
(4R,5S)-4,5-二苯基亚氨基硫脲在NaHMDS作用下发生无序去质子化反应,随后通过使用对映体纯的五氟苯基活性酯对生成的外消旋中间体进行动力学拆分。实验发现,双相控制水平极为出色(在约30%转化率时,对映体过量率可达86%-92%)。这一不对称反应是“假性拆分”的一个实例。© 2010 Elsevier Ltd. 保留所有权利。