Dioxolane-to-Bridged Acetal-to-Spiroketal via Ring-Closing Metathesis and Rearrangement: A Novel Route to 1,7- Dioxaspiro[5.5]undecanes
作者:Valerie A. Keller、Joseph R. Martinelli、Eric R. Strieter、Steven D. Burke
DOI:10.1021/ol0172368
日期:2002.2.1
Several examples of 1,7-dioxaspiro[5.5]undecane spiroketal systems have been synthesized from the common bicyclic intermediate 1 via acid-catalyzed rearrangement. Intermolecular ketalization of C(2) symmetric diene diol 3 with ketone 9 and then desymmetrization by ring-closing metathesis rapidly constructs bicyclic acetal 1. The locked conformation and steric bias of 1 allow stereoselective functionalization
1,7-二氧杂螺环[5.5]十一烷螺环系统的几个实例已通过酸催化重排从常见的双环中间体1合成。C(2)对称二烯二醇3与酮9的分子间缩酮化,然后通过闭环易位反应进行不对称化,快速构建了双环缩醛1。锁定的构象和1的空间偏向性允许在螺缩酮化之前一个或两个双键的立体选择性官能化。