Lewis Acid Catalyzed [3+2] Annulation of γ‐Butyrolactone Fused Cyclopropane with Aldehydes/Ketones

Abstract

The [3+2] annulation reaction of γ‐butyrolactone fused cyclopropanes with aldehydes or ketones under Lewis acid catalysis is described. Compared to their parent donor–acceptor (D–A) cyclopropanes, such fused bicyclic cyclopropanes demonstrated much better reactivity in this type of annulation process, providing accesses to densely substituted γ‐butyrolactone fused tetrahydrofurans bearing multiple adjacent stereogenic centers with a low catalyst loading (1–5 mol‐%), excellent diastereoselectivity, and a broad substrate scope under mild reaction conditions.