Photochemical syntheses. IX. Synthesis and reactions of 8b-Methoxy- and 4,8b-Dimethoxy-l,2-diphenyl-2a,8b-dihydrocyclobuta[a]naphthalene

The photoadduct (2e) has been prepared from 1,4-dimethoxynaphthalene and converted into the title compounds (1*d) and (1e). These compounds reacted with acetic acid, trifluoroacetic acid, formic acid or hexamethylphosphoric triamide to give (after hydrolysis) the deoxybenzoin derivatives (6a) or (6b). Ultraviolet irradiation converted (1*d) into (2d) and (1e) into (2e) at rates which were slower than the corresponding reactions of the 4-methoxy derivatives (1d), the 4,8b-dimethyl derivative (1f) or the parent compound (1a).