Gold-Catalyzed Alkyne Oxidative Cyclization/Mannich-Type Addition Cascade Reaction of Ynamides with 1,3,5-Triazinanes.

Herein, a gold-catalyzed alkyne oxidative cyclization/Mannich-type addition cascade reaction of ynamides with 1,3,5-triazinanes in the presence of a Brønsted acid has been presented. A class of functionalized fluorenes bearing a quaternary carbon center was synthesized directly with moderate to excellent yields via in situ formed α-oxo carbenes using quinoline N -oxide as the oxidant under mild reaction conditions.