First isolation of monocyclic thiabenzenes

Article abstract of DOI:10.1016/S0040-4039(00)94348-X

Monocyclic thiabenzenes, 1-alkyl-2-aroyl- (or 1-alkyl-2-cyano-) 4,5-dimethyl-thiabenzenes (6) are successfully synthesized by deprotonation of the corresponding thiopyranium salts (5) with triethylamine in ethanol. The ylide structures of 6 are elucidated by spectral and chemical evidence. Thermal reaction of 6 in several solvents provides S-alkyl rearranged products and ring-contracted ones, depending upon solvents used.