Formal Enantioselective [4+3] Cycloaddition by a Tandem Diels–Alder Reaction/Ring Expansion
作者:Xing Dai、Huw M. L. Davies
DOI:10.1002/adsc.200600363
日期:2006.11
expansion between cyclopentadiene and unsaturated aldehydes is a highly stereoselective process for the synthesis of bicyclo[3.2.1]octenones, the formal products of a [4+3] cycloaddition. When the initial cycloaddition was conducted in the presence of the chiral Lewis acid catalyst 14, the bicyclo[3.2.1]octenones were obtained in two steps in 72–85 % yields with up to 96 % ee and>98 % de.
环戊二烯和不饱和醛之间的串联Diels–Alder反应/环扩环是合成双环[3.2.1]辛烯酮(一种[4 + 3]环加成反应的正式产物)的高度立体选择性过程。当在手性路易斯酸催化剂14存在下进行初始环加成反应时,分两步获得双环[3.2.1]辛烯酮,产率为72-85%,ee高达96%,de大于98%。