Regio- and Stereocontrolled Hydrohalogenation of Ynamides with <i>N</i>‑Halosuccinimides (NXS) as the Halogen Source: Synthesis of (<i>E</i>)‑α-Haloenamides

Presented herein is a facile stereoselective construction of synthetically versatile chiral and achiral (E)-α-haloenamides under mild conditions utilizing N-halosuccinimides and diphenylphosphine oxide. This reaction is metal-free, mild, efficient, very rapid, and practical and highlights the synthetic versatility of ynamides. The reaction has a broad substrate scope; both chiral and achiral ynamides have been transformed into the corresponding (E)-α-haloenamides within a very short period of time without compromising selectivity or complexity.