Copper‐Phosphido Catalysis: Enantioselective Addition of Phosphines to Cyclopropenes

We describe a copper catalyst that promotes the addition of phosphines to cyclopropenes at ambient temperature. A range of cyclopropylphosphines bearing different steric and electronic properties can now be accessed in high yields and enantioselectivities. Enrichment of phosphorus stereocenters is also demonstrated via a Dynamic Kinetic Asymmetric Transformation (DyKAT) process. A combined experimental and theoretical mechanistic study supports an elementary step featuring insertion of a CuI‐phosphido into a carbon‐carbon double bond. Density functional theory calculations reveal migratory insertion as the rate‐ and stereo‐determining step, followed by a syn‐protodemetalation. An enantioselective hydrophosphination of cyclopropenes that occurs at ambient temperature is reported. It proceeds through a copper‐phosphido intermediate while various cyclopropylphosphines can now be accessed in high yields and enantioselectivities. Enrichment of phosphorus stereocenters is also demonstrated via a dynamic kinetic asymmetric transformation (DyKAT) process. Experimental studies and DFT calculations provide mechanistic insight.