Cleavage of sulfonamides with phenyldimethylsilyllithium

The toluene-p-sulfonamides of secondary amines and indoles are cleaved by treatment with phenyldimethylsilyllithium to give the secondary amines. Aziridine toluene-p-sulfonamides, however, are opened by attack of the silyllithium reagent on carbon to give beta-silylethyl sulfonamides, The aziridine toluene-p-sulfonamide 22 derived from norbornene is different in giving the 2-[dimethyl(phenyl)silyl]-4-methylbenzenesulfonamide 23 of exo-norbornylamine. The aziridine toluene-p-sulfonamides 26, 28 and 30, derived from methyl cinnamate, methyl acrylate and cinnamyl acetate, are also anomalous, giving 3-[N-(p-tolylsulfonyl)amino]-3-phenylpropionic acid 27, (3-[N-(p-tolylsulfonyl)amino]propionyl)dimethyl(phenyl)silane 29 and trans-cinnamyl alcohol 31, respectively, each derived by opening of the aziridine ring followed by loss of the silyl group.