Efficient construction of complex cylcopentane- or cyclohexane-fused δ-lactones employing redox activation of enals using a chiral N-heterocyclic carbene and LiCl as cooperative catalysts is described. The organocascade proceeds with excellent diastereo- (>99:1) and enantioselectivity (up to >99% ee) and comprises the formation of three bonds with three contiguous stereocenters.
描述了使用手性N-杂环卡宾和LiCl作为协同催化剂,通过烯类的氧化还原活化,高效构建复杂的
环戊烷或
环己烷稠合的δ-内酯的方法。有机级联反应具有出色的非对映异构体(> 99:1)和对映选择性(高达> 99%ee),并包括三个连续的立体中心的三个键的形成。