Highly Chemo-, Regio- and E/Z-Selective Intermolecular Heck-Type Dearomative [2+2+1] Spiroannulation of Alkyl Bromoarenes with Internal Alkynes

Described herein is a palladium-catalyzed dearomative annulation of alkyl bromoarenes with internal alkynes. Challenges in this spiroannulation include the chemoselectivity among [2 + 2 + 1], [2 + 2 + 2], and [3 + 2] annulations and the E/Z-selectivity associated with the generated exocyclic double bond. In the presence of Pd(OAc)(2) and a phosphine ligand, a variety of highly functionalized spirocyclopentadienes with an exocyclic carbon-carbon double bond are provided in good to excellent yields with high chemo-, regio-, and E/Z-selectivity via a Heck-type pathway.