STEREOSELECTIVITY AND CHEMOSELECTIVITY IN REDUCTION OF ALPHA-[PHENYL(OR METHYL)SELENO]ALKYL ARYL KETONES WITH METAL-HYDRIDES

Metal hydride reduction of a variety of alpha-[phenyl(or methyl)seleno]alkyl aryl ketones gives a mixture of threo- and erythro-P-aryl-P-hydroxyalkyl phenyl(or methyl)selenides by carbonyl reduction and 1-aryl-1-alkanol by the substitution of a phenyl(or methyl)seleno group with hydrogen. With all metal hydrides examined the formation of the threo-isomer always predominated. The addition of various metal chlorides in the reduction system did not affect the diastereoselectivity much: in a sharp contrast to the so-far known reduction of various alpha-heteroatom (N, P, O, S)-substituted ketones.