Indene derivatives including an allene functional group are readily prepared in moderate to excellent yields with high regioselectivity under very mild reaction conditions by the Pd/C-catalyzed reaction of propargylic compounds. The resulting products can be further elaborated using Pd-catalyzed annulation reactions.
Highly Regioselective Synthesis of Spirocyclic Compounds by a Palladium-Catalyzed Intermolecular Tandem Reaction