Asymmetric Reduction Of Carbonyl Compounds Containing Amino Group

A series of p-aminoketones were prepared from acetophenones via Mannich reaction. In the presence of catalytic amount of (5)-2-amino-l, 1, 3- triphenyl-propanol(Ib), which was prepared from L-phenylalanine by esterification, followed by Grignard reaction, the above aminoketones were reduced by borane stereoselectively, yielding the corresponding p-aminoalcols in good chemical and optical yields. The carbonyl group of p-(l-morpholinyl)-4-methoxy phenyl-propanone was converted to methylene by this means exceptionally. N-methyl-N-benzyl-aminoacetone was synthesized by the reaction of bromoacetone and N-methyl benzylamine, which could be converted to the corresponding secondary aminoalcohol in modest enantiomeric purity through asymmetric reduction and hydrogenolysis,...