Practical and Efficient Synthesis of (E)-α,β-Unsaturated Amides Bearing (S)-α-Methylbenzylamine from 2-Phosphonamides via Horner-Wadsworth-Emmons Reaction

The highly stereoselective synthesis of (E)-α,β-unsaturated amides bearing (S)-a-methylbenzylamine was achieved from 2-phosphonamides via Homer-Wadsworth-Emmons reaction. The starting phosphonamides are easily prepared in two steps with excellent yields via the standard Arbuzov reaction of trimethylphosphite and α-bromoamides.