Rhodium-catalyzed isomerization of 1,3-diene monoepoxides to α,β-unsaturated carbonyl compounds
作者:Susumo Sato、Isamu Matsuda、Yusuke Izumi
DOI:10.1016/0022-328x(89)85435-x
日期:1989.1
α,β-Unsaturated aldehydes and ketones are readily formed by the rhodium(I) catalyzed isomerization of 1,3-diene monoepoxides. When RhH(PPh3)4 is used as a catalyst, only (E)-α,β-unsaturated carbonyl compounds are obtained selectively. The initial 1,3-diene monoepoxides are prepared regiospecifically from α-trimethylsilyl ketones by a two step procedure, bromination and subsequent vinylative epoxidation
α,β-不饱和醛和酮很容易通过铑(I)催化的1,3-二烯单环氧化物的异构化反应形成。当将RhH(PPh 3)4用作催化剂时,仅选择性地获得(E)-α,β-不饱和羰基化合物。最初的1,3-二烯单环氧化物是由α-三甲基甲硅烷基酮通过两步程序(溴化和随后的生成的α-溴酮的乙烯基化环氧化)区域特异性地制备的。从α-三甲基甲硅烷基酮到α,β-烯酮的整体转化在形式上被视为等同于区域特异性醛醇缩合,并且还使得能够使用不对称取代的酮作为烯醇化物来源。异构化的重要性,因为它是合成ar的关键步骤描述了-turmerone。