Benzocyclobutyl phenyl sulfone. An evaluation of its potential as a precursor to substituted benzocyclobutenes and ortho-quinodimethanes

Benzocyclobutyl phenyl sulfone has been converted to several 7-substituted benzocyclobutenes via reaction of its α-sulfonyl carbanion with typical electrophiles followed by desulfonylation with Na/Hg in methanol. Two benzocyclobutenes carrying remote terminal vinyl groups have been isomerized to tricyclic ring systems upon heating at 250 °C. The o-quinodimethane obtained from thermolysis of benzocyclobutyl phenyl sulfone in toluene at 250 °C is not trapped by maleic anhydride but by the solvent toluene in a Friedel–Crafts type alkylation.