A novel class of synthetically important glycidic esters has been obtained via an asymmetric epoxidation of trans‐α‐cyano‐α,β‐unsaturated esters catalysed by a multifunctional Cinchona alkaloid‐derived thiourea/tert‐butyl hydroperoxide (TBHP) system. The glycidic esters, isolated in excellent yield with complete trans‐diastereocontrol and high enantioselectivity, proved to be versatile building blocks
Efficient Highly Selective Synthesis of Methyl 2-(Ethynyl)alk-2(<i>E</i>)-enoates and 2-(1′-Chlorovinyl)alk-2(<i>Z</i>)-enoates from 2-(Methoxycarbonyl)-2,3-allenols
作者:Youqian Deng、Xin Jin、Chunling Fu、Shengming Ma
DOI:10.1021/ol9004273
日期:2009.5.21
Highly regio- and stereoselective reactions of readily available 2-(methoxycarbonyl)-2,3-allenols 1 with oxalylchloride in the presence of Et3N or DMSO afforded methyl 2-(ethynyl)alk-2(E)-enoates (E)-2 and 2-(1′-chlorovinyl)alk-2(Z)-enoates (Z)-3, respectively, in moderate to good yields.