New Strategic Reactions for Organic Synthesis: Catalytic Asymmetric C−H Activation α to Oxygen as a Surrogate to the Aldol Reaction
作者:Huw M. L. Davies、Rohan E. J. Beckwith、Evan G. Antoulinakis、Qihui Jin
DOI:10.1021/jo034533c
日期:2003.8.1
The C-H activation of silyl ethers by means of rhodium carbenoid-induced C-H insertion represents a very direct method for the stereoselective synthesis of silyl-protected beta-hydroxy esters. The reaction can proceed with very high regio-, diastereo-, and enantioselectivity and represents a surrogate to the aldol reaction. The reaction is catalyzed by the rhodium prolinate complex Rh(2)(S-DOSP)(4)
借助于铑类胡萝卜素诱导的CH插入而实现的甲硅烷基醚的CH活化代表了一种立体选择性合成甲硅烷基保护的β-羟基酯的非常直接的方法。该反应可以以非常高的区域,非对映和对映选择性进行,并且代表了醛醇缩合反应的替代物。反应由脯氨酸铑络合物Rh(2)(S-DOSP)(4)催化。高化学选择性的关键要求是使用供体/受体取代的类胡萝卜素,例如衍生自芳基重氮乙酸甲酯的那些。可以使用多种甲硅烷基醚,例如烯丙基甲硅烷基醚,四烷氧基硅烷,甚至简单的三甲基甲硅烷基烷基醚。通常,CH活化优先发生在亚甲基位置,因为反应性受空间和电子效应之间的微妙平衡控制。