Horner-Wadsworth-Emmons Reagents for E and Z-Selective Synthesis

Horner-Wadsworth-Emmons reagent 1 react with aldehydes and ketones to give corresponding E-α,β-unsaturated N-methoxy-N-methylamides.¹⁾ The presence of the Weinreb-Nahm amide, which can be transformed to aldehydes and ketones, makes 1 a useful reagent as a bifunctional building block.²⁾ In contrast, Ando reported an useful Z selective olefination using Horner-Wadsworth-Emmons reagent (Ando-type reagent) 2.³⁾ Synthetic applications of 2 are being studying.⁴⁾