Catalytically Generated Allyl Cu(I) Intermediate via Cyclopropene Ring-Opening Coupling en Route to Allylphosphonates

An efficient generation of functionalized allyl copper­(I) species via cyclopropene ring-opening coupling reaction is reported, which enables stereoselective access to allylphosphonates. Mechanistic studies uncovered stereochemistry to be controlled by both ligand and substrate electronics, with the latter likely arising from pronounced arene-Cu­(I) interaction in electron-deficient substrates. The study unravels a novel approach to access functionalized nucleophilic allylcopper species upon which three-component coupling reactions might be developed.