Photochemical reduction of 1,2-diketones in the presence of TiO2

1,2-Diketones, camphorquinone and 1-phenyl-1,2-propanedione, are converted to the corresponding alpha -hydroxyketones in moderate to good yields by Ti O2-catalyzed photochemical reactions in deoxygenated alcoholic media. The r eduction yield for 1-phenyl-1,2-propanedione is considerably increased by a ddition of water or triethylamine