N-SULFONYLAMIDINES. PART III. A NEW REARRANGEMENT REACTION OF N-ALKYLSULFONYL-AMIDINES: SYNTHESIS OF ENAMINES, β-AMINOSULFONYL-ENAMINES AND 4H-THIAZETE-S,S-DIOXIDES.

Article abstract of DOI:10.1016/S0040-4020(01)96105-8

On reaction with lithium diisopropylamide, N-alkylsulfonylamidines (1) (a new class of amidines) rearrange by intramolecular attack of the carbanion generated α to the SO2 group on the amidine carbon.Through a cyclic thiazetidine intermediate three main classes of compounds are formed, i.e. enamines (8), β-aminosulfonylenamines (9) and 4H-thiazete-S,S-dioxides (6).In the rearrangement products 8 and 9 the two carbon moieties of the amidine formerly linked to the N and S atoms, respectively, become linked together, with the formation of a new C-C bond.