Copper-Catalyzed One-Pot Synthesis of Functionalized 1,4-Dihydroazete Derivatives from Sulfonyl Azides, Terminal Alkynes, and Tetramethylguanidine

Ketenimine intermediates generated by the addition of copper acetylides to sulfonyl azides are trapped by tetramethyl­guanidine to afford 1,4-dihydro- N , N -dimethyl-3-aryl(alkyl)-4-­aryl(alkyl)sulfoniminoazet-2-amine derivatives in moderate to good yields.