[摘要]：2H-Cyclohepta[b]furan-2-one (I) reacted with Me2S.(HO3SCF3)2 to give dimethyl(2-oxo-2H-cyclohepta[b]fur-3-yl)sulfonium triflate, which was treated with Et3N to give 3-methylthio-2H-cyclohepta[b]furan-2-one. The latter sulfide was oxidized with m-CPBA to give the corresponding sulfoxide and sulfone. The sulfoxide thermally underwent coupling reaction to give 3,3'-bi-2H-cyclohepta[b]furan-2-one. The sulfoxide reacted with triflic anhydride to afford the resp. sulfonium ion at lower temp., which reacted with I to give the corresponding dicycloheptafurylsulfonium salt. Subsequent treatment with Et2NH or Et3N gave the corresponding thioether.
