Asymmetric [2,3]-sigmatropic Wittig rearrangement of chiral α-allyloxy-hydrazones

Article abstract of DOI:10.1016/0040-4020(95)00982-5

The asymmetric [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, optically active aliphatic and aromatic α-hydroxyketones 5 or protected cyanohydrins 10 and α-hydroxyaldehydes 11 respectively, can be generated in high enantiomeric excesses (92-98%) and syn-selectivities (88->99%) after chromatographic purification and removal of the auxiliary.