Abstract
1,3-Dipolar cycloadditions of azomethine ylides with thiocarbonyl compounds have been used for the preparation of N-unsubstituted 1,3-thiazolidines. The reactive 1-phenyl-N-(trimethylsilyl)azomethine ylide (1c) was generated in situ by treatment of N-(benzylidene)[(trimethylsilyl)methyl]amine (6) with trimethylsilyl triflate and CsF in HMPA. All cycloadditions proceeded non-regioselectively, which led to mixtures of 4-phenyl- and 2-phenyl-substituted 1,3-thiazolidines.