Chiral β-nitrohydrazones 7 can be easily prepared in good yields and diastereoselectivities by non catalyzed Michaeladdition of formaldehydeSAMPhydrazone 6 to simple nitroolefins.
The enantioselective synthesis of α-substituted β-nitro nitriles 4 and β-nitroaldehydes 5 by Michael addition of formaldehyde SAMP-hydrazone 1 to nitroalkenes 2 in excellent overall yields and high enantiomeric excesses (ee=90->99%) is described. Compound 1 constitutes a neutral chiral formyl anion and cyanide equivalent. The absolute configuration was determined by X-ray structure analysis of the crystalline SAMP-hydrazone 1,4-adduct 3e.
本文介绍了通过将甲醛 SAMP- 酰腙 1 迈克尔加成到硝基烯烃 2 中,以优异的总收率和较高的对映体过量(ee=90->99%),对映选择性地合成δ-取代的δ-硝基腈 4 和δ-硝基醛 5。化合物 1 由中性手性甲酰基阴离子和氰化物等价物组成。通过对晶体 SAMP-hydrazone 1,4-adduct 3e 进行 X 射线结构分析,确定了其绝对构型。