3-Methylsulfanylfuran and 3-phenylsulfanylfuran were found to undergo facile, regioselective and stereoselective Diels−Alder (DA) cycloaddition to a variety of cycloalkenones under high pressure to give the corresponding ring-annulated 7-oxabicyclo[2.2.1]heptene derivatives in good yields. The vinyl sulfide groups in the adducts were oxidized to relatively stable vinylsulfones, which were utilized