Gold-Catalyzed Intermolecular Alkyne Insertion into the N-S Bond in Sulfenamides.

Gold-catalyzed reactions between sulfenamides and terminal alkynes proceeded via cis -insertion of alkynes into the N-S bond in sulfenamides, affording the corresponding β-sulfenylenamines in yields up to 90%. Mechanistic studies revealed that the reactions proceeded via nucleophilic attack of the sulfenamide nitrogen atom on the π-activated alkyne, followed by tosylate-assisted intermolecular transfer of the sulfenyl group.