An organocatalytic cis-selective approach to bicyclic δ-lactones

Abstract

A new, cis-selective, approach for the synthesis of bicyclic δ-lactones bearing a fused cyclohex-2-en-1-one moiety is described. The strategy utilizes a cascade reactivity of cyclic 1,3-diketones and 3-arylidenefuran-2(3H)-ones with the butenolide-ring-opening reaction enabling the construction of the δ-lactone framework. It benefits from broad scope, high enantioselectivity and excellent cis-diastereoselectivity.