Substituted 1-Allyl-2-allenylbenzenes via Palladium-Catalyzed Allylallenylation of Benzyne Derivatives

An efficient method for the synthesis of 1-allyl-2-allenyl benzenes via palladium-catalyzed three-component assembly of benzynes, allyl chlorides, and allenylstannanes is described. Substituted benzyne precursors la-e undergo three-component assembly with various allylic chlorides 2a-e and allenylstannanes in the presence of Pd(dba) 2 /dppe (5 mol%), and cesium fluoride in acetonitrile at ambient temperature affording 1-allyl-2-allenyl benzenes 4a-k in good to excellent yields. The possible mechanism for the present catalytic reaction is proposed.