Rhodium(I)-Catalyzed Decarbonylative Spirocyclization through C-C Bond Cleavage of Benzocyclobutenones: An Efficient Approach to Functionalized Spirocycles

The rhodium-catalyzed formation of all-carbon spirocenters involves a decarbonylative coupling of trisubstituted cyclic olefins and benzocyclobutenones through CC activation. The metal-ligand combination [{Rh(CO)(2)Cl}(2)]/P(C6F5)(3) catalyzed this transformation most efficiently. A range of diverse spirocycles were synthesized in good to excellent yields and many sensitive functional groups were tolerated. A mechanistic study supports a hydrogen-transfer process that occurs through a -H elimination/decarbonylation pathway.