Disproportionation of condensed thiopyrans with trifluoroacetic and deuterotrifluoroacetic acids

Article abstract of DOI:10.1007/BF00503527

The disproportionation of isomeric 2,4-diphenyl-5,6-tetramethylene-4H-thiopyran,-6H-thiopyran, and 2,4-diphenyl-5,6,7,9-tetrahydrothiochromene with trifluoroacetic and deuterotrifluoroacetic acids was investigated for the first time. The direction of protonation of the sulfides was established, and this made it possible to form a judgment regarding the structure of the intermediate carbonium ions, which are hydride-ion acceptors. The correctness of the mechanism of disproportionation of condensed two-ring sulfides with a 4H-thiopyran ring was proved. A mechanism for the disproportionation of isomeric 2,4-diphenyl-5,6-tetramethyl-6H-thiopyran and 2,4-dipheny1-5,6,7,9-tetrahydrothiochromene was proposed.