Cu(I)- or Ag(I)-Catalyzed Regio- and Stereocontrolled trans-Hydrofluorination of Ynamides

With Et3N·3HF as the fluorinating reagent, a copper­(I)- or silver­(I)-catalyzed β/α-site-regiocontrolled trans-hydrofluorination of alkynamides has been achieved, affording the corresponding fluoro enamides in moderate to nearly quantitative yields with high regio- and stereoselectivity, respectively. The reaction proceeds under mild reaction conditions and exhibits good functional group tolerance. Further, the deuterium-labeling experiment confirmed the existence of the alkenylcopper intermediate.