Gold-Catalyzed Formal Dehydro-Diels-Alder Reactions of Ene-Ynamide Derivatives Bearing Terminal Alkyne Chains: Scope and Mechanistic Studies.

A new protocol for the synthesis of a variety of N-containing aromatic heterocycles by a formal gold-catalyzed dehydro-Diels-Alder reaction of ynamide derivatives has been developed. Deuterium-labeling experiments and kinetic studies support the involvement of a dual gold catalysis mechanism in which a gold acetylide moiety adds onto an aurated keteneiminium.