Palladium-Catalyzed Unsymmetrical bis-Allylation of Active Methylene Compounds Using Vinyl Sulfoxonium Ylides and Allyl Esters.

Unsymmetrical 1,6-dienes are valuable synthetic intermediates, yet their selective synthesis remains challenging. We report a palladium-catalyzed synthesis of unsymmetrical 1,6-dienes from vinyl sulfoxonium ylides, allyl esters, and active methylene compounds under mild, base-free conditions. The method exhibits a broad substrate scope and provides diverse dienes in moderate to good yields. Mechanistic studies suggest the involvement of a ylide-derived allylic intermediate in the selective bis-allylation process. An intramolecular variant proceeds through a distinct cyclopropane-mediated decarboxylative allylation pathway, providing complementary access to unsymmetric 1,6-diene frameworks.