Photochemical reduction of benzophenone by 2-butyne-l, 4-diol and photochemical solvolysis reactions of beta-phenethyl compounds

The irradiation of a dioxane solution of benzophenone in the presence of 2-butyne-1, 4-diol leads to reduction of the ketone rather than addition across the triple bond of the alkyne. However, great difficulty was encountered in identifying the product due to the formation of an organic complex involving benzopinacol and the dioxane. Nuclear magnetic resonance and ultraviolet spectral data confirm the presence of the complex. An attempt was made to induce a known ground state reaction by photochemical means. This ground state reaction is known to proceed through an ethylene phenonium ion intermediate. Both β-phenethyl bromide and β-phenethyltrimethylammonium tetrafluoroborate were irradiated in alcoholic solvents, but no reaction was observed