Photoproducts from 4,4′-dimethoxy-2,2′-binaphthyl-1,1′-quinone

Exposure of its solutions to visible light causes the title quinone (1) to undergo cyclisations and to react with water, ethanol, and carbon tetrachloride. The products include the furo-1,4-quinones (2; R = Me and Et) and the related 1,2-quinone (4; R = Me), the hydroxy-quinones (3; R = Me and Et), the lactone (5), and the quinone dichloromethide (7).