First Examples of Enantioselective Palladium-Catalyzed Thiocarbonylation of Prochiral 1,3-Conjugated Dienes with Thiols and Carbon Monoxide: Efficient Synthesis of Optically Active β,γ-Unsaturated Thiol Esters
作者:Wen-Jing Xiao、Howard Alper
DOI:10.1021/jo0103773
日期:2001.9.1
A catalyst system based on [Pd(OAc)(2)]/(R,R)-DIOP has been found to effect asymmetric thiocarbonylation of certain prochiral 1,3-dienes to produce good yields of optically enriched beta,gamma-unsaturated thiol esters. The reaction was performed under an atmosphere of carbon monoxide (400 psi) at 110 degrees C in methylene chloride for 60 h. The asymmetric thiocarbonylation proceeded with good to excellent
已发现基于[Pd(OAc)(2)] /(R,R)-DIOP的催化剂体系可实现某些前手性1,3-二烯的不对称硫羰基化反应,从而产生良好收率的光学富集的β,γ-不饱和硫醇酯。该反应在110℃的一氧化碳(400psi)气氛下在二氯甲烷中进行60小时。不对称硫代羰基化反应具有良好的对映体选择性(至多89%ee)。立体选择性受手性膦配体和底物的结构以及反应条件的强烈影响。假定对映终止步骤是将CO插入到π-烯丙基铝中间体中。