べンゾ[b]フラン-2,3-ジオン類と2,3-ジメチル-2-ブテンとの光化学反応

Abstract

Photochemical reactions of benzo[b]furan-2, 3-diones with 2, 3-dimethylbut-2-ene in degassed solutions were investigated. Photoreaction of benzo[b]furan-2, 3-diones with 2, 3-dimethylbut-2-ene in degassed nonpolar solvents selectively gave dioxene derivatives, [4+2]photocycloadduct in excellent yields. One the other hand, photoreaction of benzo[b]furan-2, 3-diones with 2, 3-dimethylbut-2-ene in degassed polar solvents underwent not only [4+2]photocycloaddition but also [2+2]photocycloaddition of substrates to give dioxene derivatives and oxetan derivatives in moderate yields. In addition, oxetan derivatives underwent photolysis to give isopropylidene derivatives.