Ligand-controlled stereodivergent proton migration in skipped enynes

Having full control over the regio- and stereoselective isomerization of C=C double bonds is essential for accessing stereochemically defined olefins. However, most of the double-bond migration techniques used in the past decades have relied on precious-metal hydrides or radical-based approaches. These methods often suffer from reversible equilibria, hydrogen scrambling, incomplete E / Z selectivity, and high costs. Herein, we demonstrate a nonprecious, reductant-free, and atom-economical copper(I)-catalyzed regioselective and stereodivergent proton migration in skipped enynes. The developed method demonstrates high functional group compatibility and good Z / E selectivity under mild conditions and provides a variety of E- or Z- conjugated 1,3-enynes. Mechanistic and density functional theory (DFT) studies reveal the ligand-controlled proton migration process in detail.