Enantioselective Michael Additions of Nitromethane by a Catalytic Double Activation Method Using Chiral Lewis Acid and Achiral Amine Catalysts
作者:Kennosuke Itoh、Shuji Kanemasa
DOI:10.1021/ja027313+
日期:2002.11.1
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
R,R-DBFOX/Ph.Ni(ClO4)2.3H2O 和非手性胺碱可有效催化硝基甲烷与 1-(2-烯酰基)-3,5-二甲基吡唑的反应,催化负载量为 10 mol% , 以高化学产率得到 1-(3-取代的 4-硝基丁酰基)-3,5-二甲基吡唑。已实现高达 98% ee 的出色对映选择性。硝基部分可以很容易地在常压下在 Raney 镍上还原,然后同时环化,在常规处理后得到 4-取代的 2-吡咯烷酮衍生物的对映异构体。该方法可成功应用于 (R)-(-)-咯利普兰的短步合成。