Rearrangement of 1-phenyl-3,4-dihydro-1H-2-benzothiopyranium 2-methylides

trans-1-Phenyl-2-benzothiopyranium 2-methylides (trans-5), generated by fluoride ion-induced desilylation of trans-1-(4-substituted phenyl)-2-(trimethylsilylmethyl)-3,4-dihydro-1H-2-benzothiopyranium triflates (trans-4) in DMSO, rearranged to 3-substituted 7,8-dihydro-5H, 13H-dibenzo[c, f]thionines 6(Sommelet–Hauser rearrangement products), 1-(4-substituted phenyl)-1,2,4,5-tetrahydro-3-benzothiepines 7(Stevens rearrangement products) and (4-substituted phenyl)(2-vinylphenyl)methyl methyl sulfides 8(Hofmann degradation products). Reactions carried out in the presence of oxygen, gave (4-substituted phenyl) 2-[2-(methylsulfanyl)ethyl]phenyl ketones 9 as the main products.