Noncanonical Cation−π Cyclizations of Alkylidene β-Ketoesters: Synthesis of Spiro-fused and Bridged Bicyclic Ring Systems
作者:Dylan E. Parsons、Alison J. Frontier
DOI:10.1021/acs.orglett.9b00094
日期:2019.4.5
conditions employed, it is possible to achieve selective synthesis of the three different types of products, including 1-halo-3-carbomethoxycyclohexanes, spiro-fused tricyclic systems, and [4.3.1] bridged bicyclic ring systems. All three reactions begin with 6-endo addition of an olefin to the alkylidene β-ketoester electrophile, followed by one of three different cation capture events.
描述了在带有侧链烯烃的亚烷基β-酮酸酯上引发的三个阳离子-π环化级联反应。取决于烯烃的取代方式和所用的反应条件,有可能实现三种不同类型产物的选择性合成,包括1-卤-3-羰甲氧基环己烷,螺稠合三环系统和[4.3.1]桥联双环环系统。所有这三个反应均始于将烯烃的6-内酯加成至亚烷基β-酮酸酯亲电子试剂中,然后是三种不同的阳离子捕获事件之一。