Alkylindan synthesis via an intermolecular [3+2] cycloaddition between unactivated alkenes and in situ generated p-quinomethanes

Alkylindans were synthesized by the intermolecular [3+2] cycloaddition of in situ generated p-quinomethanes and aliphatic alkenes. In a highly concentrated lithium perchlorate in nitromethane, p-quinomethanes were generated by DDQ oxidation of corresponding alkylphenols, and the desired cycloaddition reaction was completed efficiently to give various indans.