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.