The facile synthesis of 1-benzoazepine derivatives via gold-catalyzed regioselective cycloisomerization reactions of N-(o-alkynylaryl)-N-vinyl sulfonamides

Abstract

Gold-catalyzed, regioselective cycloisomerization of N-(o-alkynylaryl)-N-vinyl sulfonamides afforded high yields of 2-sulfonylmethyl-1-benzoazepine derivatives. This 7-endo-dig selective cyclization proceeds via the incorporation of an exocyclic double bond by a labile 1-benzoazepine intermediate. The cyclization substrates were assembled in two steps from readily available materials using Sonogashira coupling and a Cs₂CO₃-mediated formal vinylic substitution.