Asymmetric synthesis of α-substituted nitriles and cyanohydrins by oxidative cleavage of chiral aldehyde hydrazones with magnesium monoperoxyphthalate
作者:Dieter Enders、Andrew Plant、Dirk Backhaus、Ulrich Reinhold
DOI:10.1016/0040-4020(95)00647-q
日期:1995.9
Optically active α- and α,β-substituted aldehyde hydrazones 2, 4, and 7, which are readily available by asymmetric alkylation. Michael addition or [2,3]-Wittig rearrangement of chiral hydrazones can be transformed into nitriles 3 and 5 or cyanohydrins 8 by MMPP mediated oxidation, respectively. This synthetic sequence offers a C-C connective entry into optically active functionalised nitriles with
Asymmetric [2,3]-sigmatropic wittig rearrangement of chiral α-allyloxy-hydrazones
作者:Dieter Enders、Dirk Backhaus、Jan Runsink
DOI:10.1016/0040-4020(95)00982-5
日期:1996.1
[2,3]-Wittig rearrangement of chiral α-allyloxy-hydrazones (S)-3 and (S)-7 proceeds with very good yields (72 – 100%) together with high syn-selectivities (87 – 97%) and asymmetric inductions (63 – 92%) to give the corresponding α-hydroxyhydrazones 4 and 8. Depending on the substitution patterns of the starting material, opticallyactive aliphatic and aromatic α-hydroxyketones 5 or protected cyanohydrins