A Sequential Pd-AAA/Cross-Metathesis/Cope Rearrangement Strategy for the Stereoselective Synthesis of Chiral Butenolides.

A practical and highly enantio- (up to 94:6 er) and diastereoselective (up to >20:1 dr) synthesis of γ-butenolides bearing two adjacent stereogenic centers is reported featuring a sequential direct palladium-catalyzed asymmetric allylic alkylation/( E)-selective cross-metathesis/[3,3]-sigmatropic Cope rearrangement from readily available α-substituted (5 H)-furan-2-ones.