Decarboxylative Hydroalkylation of Alkynes via Dual Copper-Photoredox Catalysis

A novel photoredox strategy for the synthesis of a wide range of allylic amines and ethers from carboxylic acids and alkynes has been developed. This approach relies on the perturbation of the ground-state electronical properties of terminal alkynes through the formation and photoexcitation of copper acetylide intermediates. This process takes place through cooperative copper and organic photoredox catalysis and can be carried out in stereodivergent manner. Thus, a systematic multivariate HTE screening spotlighted that a switch in the stereochemical outcome can be provoked by choosing an appropriate combi-nation of ligand and base. The developed methodology has been applied to the stereoselective coupling of primary, second-ary and tertiary alkyl radicals with (hetero)aromatic terminal alkynes. As an additional practicality, similar reaction condi-tions allowed for the use of aromatic amines as radical precursors in a cross dehydrogenative coupling for the direct vinyla-tion of inactivated C–H bonds.