Base-Mediated Allylic Defluorinative Functionalizations of β‑CF2H‑1,3-enynes Enables the Construction of Terminal Monofluoroenynes

The base-mediated allylic defluorinative functionalization of β-CF2H-1,3-enynes with nucleophiles is described, affording terminal monofluoroalkenes bearing an alkynyl group in synthetically useful yields and Z/E selectivities. Importantly, the resultant Z/E mixture could be separated by flash chromatography in all cases; thus, stereoisomerically pure monofluoroenynes were obtained. Postsynthetic modifications of the synthesized monofluoroenynes were also accomplished to access diverse molecular structures. Computational studies disclosed the origin of the diastereoselectivity.