Photoinduced Intermolecular [4+2] Cycloaddition Reaction for Construction of Benzobicyclo[2.2.2]octane Skeletons

A novel
and efficient method for the synthesis of highly substituted
benzobicyclo[2.2.2]­octane skeletons has been explored. Under UV-light
irradiation, o-divinylbenzenes underwent a pericyclic reaction to
form the cyclic o-quinodimethane intermediates which were subsequently
reacted with olefins through [4+2] addition to construct the benzobicyclo[2.2.2]­octane
skeletons in mild conditions. Gram scale reactions demonstrated the
synthetic potential application of this protocol.