Copper‐Phosphido Catalysis: Enantioselective Addition of Phosphines to Cyclopropenes**

Abstract

Abstract 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 Cu I ‐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.