PHOTOINDUCED MOLECULAR-TRANSFORMATIONS .156. NEW PHOTOADDITIONS OF 2-HYDROXY-1,4-NAPHTHOQUINONES WITH NAPHTHOLS AND THEIR DERIVATIVES

Dinaphtho[2,1-b;1',2'-d]furan-12,13-diones are produced in one-step in up to 45% yield by a (3+2) photoaddition of 2 hydroxy-1,4-naphthoquin ones with 2-naphthol, while (+/-)-(6a alpha,6b beta,12a beta,12b o-12b -hydroxydinaphtho-[1,2-a;1',2'-c]cyclobutenes (14-16%), arising from t he stereoselective addition of a (2+2) photoaddition, are products in the photoaddition of 2-hydroxy-1,4-naphthoquinone with 2-methoxynaphth alene and with 2-naphthyl acetate. The photoaddition of 2-hydroxy-1,4- naphthoquinone with 2-methoxynaphthalene also gave ydroxy-3-(2-methoxy naphth-1-yl)-1,4-naphthoquinone (23%) as an accompanying product. Simi lar irradiation of a solution of 2-hydroxy-1,4-naphthoquinone with 1-m ethoxynaphthalene in acetone gave 3a-methoxydinaphtho[1,2-b;2',3'-d]fu ran-7,12-dione arising from a (3+2) photoaddition in 24% yield. The pr obable mechanisms for the formation of the photoadducts are discussed.