Domino retro Diels-Alder/Diels-Alder reaction: an efficient protocol for the synthesis of highly functionalized bicyclo[2.2.2]octenones and bicyclo[2.2.2]octadienones.

A novel and convenient approach, the domino retro Diels-Alder/Diels-Alder reaction sequence for highly stereo- and regioselective synthesis of various bicyclo[2.2.2]octenone and bicyclo[2.2.2]octadienone derivatives is presented. Thus, the masked o-benzoquinones (MOBs) 2a-e generated by the pyrolysis of the respective dimers 3a-e participated in this novel synthetic strategy with a variety of olefinic and acetylenic dienophiles at 220 degrees C to provide the title compounds in good to excellent yields.