Addition of furans to electron-rich olefins through photo-induced electron-transfer in the presence of electron acceptors

Photoaddition of furan and 2-methylfuran to aromatic olefins such as indene and 1,1-diphenyl-ethylene in the presence of 1-cyanonaphthalene or 1,4-dicyanonaphthalene gives (4 + 2) cycloadducts and/or alkyl-substituted furan derivatives.