Intramolecular hydroamination of difluoropropargyl amides:: Regioselective synthesis of fluorinated β- and γ-lactams

Functionalized gem-difluoro beta- and gamma-lactams were synthesized through a novel intramolecular hydroamination reaction of difluoropropargyl amides.beta-Lactams were obtained via a Baldwin disfavored 4-exo-digonal cyclization using palladium acetate as the catalyst, whereas gamma-lactams were produced under basic conditions. Acid hydration of gamma-lactams produced ketoamides or hemiaminals selectively.