Tropene Derivatives by Sequential Intermolecular and Transannular, Intramolecular Palladium-Catalyzed Hydroamination of Cycloheptatriene

A consecutive inter- and intramolecular hydroamination of cycloheptatriene with primary aromatic amines, benzylic amines, and beta-phenethylamines occurs to produce pharmaceutically relevant tropene (8-azabicyclo[3.2.1]octene) frameworks in good to excellent yields. This reaction occurs in the presence of a catalyst generated from palladium trifluoroacetate, 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene and a mild acid. Mechanistic studies reveal that the overall process has some reversible steps, but that the rate of these reverse reactions are far slower than the rates of the forward catalytic process.