Journal of the American Chemical Society

Enantioselective Michael additions of nitromethane by a catalytic double activation method using chiral Lewis acid and achiral amine catalysts

K Itoh, S Kanemasa

Index: Itoh, Kennosuke; Kanemasa, Shuji Journal of the American Chemical Society, 2002 , vol. 124, # 45 p. 13394 - 13395

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Citation Number: 138

Abstract

Reactions of nitromethane with 1-(2-alkenoyl)-3, 5-dimethylpyrazoles can be effectively catalyzed by R, R-DBFOX/Ph⊙ Ni (ClO4) 2⊙ 3H2O and achiral amine bases, each in a catalytic loading of 10 mol%, to give 1-(3-substituted 4-nitrobutanoyl)-3, 5-dimethylpyrazoles in high chemical yields. Excellent enantioselectivities up to 98% ee have been achieved. The nitro moiety can be easily reduced on Raney nickel at atmospheric pressure, followed ...