Phosphine-controlled divergent reactions of MBH-carbonates with azaheptafulvenes: access to o-anilinyl diene and benzazepine derivatives

Abstract

Here, we disclose a phosphine-catalyst-controlled divergent cascade reaction of MBH-carbonates with azaheptafulvenes. In the presence of PPh₃ in toluene at 100 °C, MBH-carbonates underwent 1,8-conjugated addition/ring contraction cascade reactions with azaheptafulvenes, to provide o-aminophenyl diene in moderate to good yields with moderate chemoselectivity. When the phosphine catalyst was switched to PCy₃ in this process, a benzazepine derivative was constructed through a formal [8 + 3] annulation/ring contraction cascade with up to 98% yield and >19/1 chemoselectivity.