A Novel Synthesis of 1,2-Dialkylthio- and 2-Alkoxy-1-alkylthioethenes from β-Arylthioalkenylselenonium Salts and Its Application to the Synthesis of Medium-Membered Heterocycles Containing S and O Atoms

The treatment of alkynylselenonium salts and thiophenol derivatives with a catalytic amount of triethylamine afforded β-arylthiovinylselenonium salts in good yields. The reactions of the vinylselenonium salts with nucleophiles produced (Z)-β-arylthio-α-functionalized ethenes in high yields. In addition, the vinylselenonium salts bearing a hydroxy group, 2d-f, 2h, underwent intramolecular cyclization upon treatment with sodium hydride to produce medium-membered heterocyclic compounds containing S and O atoms.