Enantioselective Epoxidation of α,β-Enones by Electrophilic Activation with a BINOL-Zinc Catalyst
作者:Ana Minatti、Karl Heinz Dötz
DOI:10.1002/ejoc.200500606
日期:2006.1
affords, in situ, a catalyst for homogeneous epoxidation of (E)-α,β-enones to the corresponding trans-epoxy ketones. tert-Butyl hydroperoxide (TBHP) and cumene hydroperoxide (CMHP) are effective terminal oxidants for this process. Enantiomeric excesses of up to 96 % can be achieved conveniently at room temperature. Mechanistic investigations point towards an electrophilic activation of the substrates
BINOL 和二烷基锌试剂 R2Zn 的组合提供了原位催化剂,用于将 (E)-α,β-烯酮均匀环氧化成相应的反式环氧酮。叔丁基氢过氧化物 (TBHP) 和氢过氧化枯烯 (CMHP) 是该过程的有效末端氧化剂。在室温下可以方便地实现高达 96% 的对映体过量。机理研究表明,手性 BINOL-锌催化剂对底物进行了亲电活化,并随后对氧化剂进行了亲核攻击。非线性效应、绝对产物构型以及 NMR 研究也支持这一机制建议。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)