Palladium-Catalyzed Domino Cyclization/Alkylation of Terminal Alkynes: Synthesis of Alkynyl-Functionalized Azaindoline Derivatives

A novel palladium-catalyzed domino cyclization/alkylation of terminal alkynes was achieved for the synthesis of alkynyl-functionalized 3,3-disubstituted azaindoline derivatives under air atmosphere conditions. Various types of terminal alkynes, including aromatic alkynes, aliphatic alkynes, and ferrocene acetylene, can undergo the process successfully. The protocol provides a range of alkynyl-functionalized azaindoline scaffolds bearing a quarternary carbon center.