PHOTO-REDUCTION OF ARYL KETONES BY AMIDES AND LACTAMS - SYNTHETIC APPLICATION

Benzophenone is photoreduced by lactams and amides. In this reaction the hydrogen atom α to the lactam nitrogen is abstracted regioselectively, and radical coupling leads to adducts. The reaction is general and comparable to an hydroxyalkylation α to the nitrogen atom. Its quantum yield is 0.13 in the case of N-methyl 2-pyrrolidone in CH3CN or in C6H6. Adducts obtained with acetophenone and p,p'-dimethoxy benzophenone are described. The reduction of adduct 12yields the diphenylethanolamine 22 and 12 is dehydrated to give the enamide 21. © 1979.