High-pressure-promoted Diels-Alder reactions between cycloalkenones and 3-methylsulfanylfuran and 3-phenylsulfanylfuran

3-Methylsulfanylfuran and 3-phenylsulfanylfuran were found to undergo facil e, regioselective and stereoselective Diels-Alder (DA) cycloaddition to a v ariety 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 vinylsulf ones, which were utilized for synthetic transformations such as further DA cycloadditions and epoxidation.