A kinetic separation method for the stereoselective preparation of (Z)- and (E)-monofluoroenynes from E/Z mixtures of 1-bromo-1-fluoroolefins
作者:Xin Zhang、Donald J. Burton
DOI:10.1016/s0022-1139(01)00529-2
日期:2001.12
under similar conditions and longer reaction times (48 h) to give pure (E)-monofluoroenynes in excellent yields (78–89%). Thus, E/Z mixtures of 1-bromo-1-fluoroolefins could be kinetically separated into (Z)- and (E)-monofluoroenynes. This methodology provides a simple one-step unequivocal route to the isomerically pure (Z)- and (E)-monofluoroenynes from the readily available 1-bromo-1-fluoroolefins.
1-溴-1-氟烯烃与1-炔烃的E / Z混合物与催化的Pd(PPh 3)2 Cl 2和CuI在室温下在三乙胺中的反应(16-24小时后)主要是(Z)-单氟炔(Z / E > 92/8),收率良好。通常可以通过色谱分离粗制的Z / E混合物来获得纯的(Z)-单氟炔。可以回收纯的(Z)-1-溴-1-氟烯烃,并在相似的条件下和更长的反应时间(48 h)下与1-炔烃反应,得到纯的(E)-一氟代炔类化合物,收率极高(78-89%)。因此,可以将1-溴-1-氟烯烃的E / Z混合物动力学分离为(Z)-和(E)-单氟炔烃。该方法学提供了一种简单的一步一步明确路线,从容易获得的1-溴-1-氟烯烃中获得异构纯的(Z)-和(E)-单氟炔烃。