Stereoselective Construction of Adjacent Quaternary Chiral Centers by the Ireland-Claisen Rearrangement: Stereoselection with Esters of Cyclic Alcohols
作者:Armen Zakarian、Zhenhua Gu、Aaron Herrmann、Craig Stivala
DOI:10.1055/s-0029-1219965
日期:2010.7
a-disubstituted enolates derived from esters of cy- clic alcohols. Highly stereoselective enolizaitions could be generally achieved using N-benzyl Koga-type bases by matching chirality of the ester and the base. The (3,3)-sigmatropic rearrange- ment took place in good yields and moderate diastereoselectivity forming two adjacent quaternary stereogenic centers, and generally proceeding through a chairlike
这项工作描述了对衍生自环醇酯的 α,α-二取代烯醇化物的爱尔兰-克莱森重排的研究。通过匹配酯和碱的手性,使用 N-苄基 Koga 型碱通常可以实现高度立体选择性烯醇化。(3,3)-sigmatropic 重排以良好的产率和适度的非对映选择性发生,形成两个相邻的四元立体中心,并且通常通过椅子状过渡态进行。