Copper-Catalyzed Cascade Radical Addition–Cyclization Halogen Atom Transfer between Alkynes and Unsaturated α‑Halogenocarbonyls

A Cu-catalyzed cascade radical addition/cyclization/halogen atom transfer between alkynes and α-halogeno-γ, δ-unsaturated carbonyl compounds for the synthesis of various substituted cyclopentenes is described. Since up to four Csp3–Csp2 bonds, two Csp3–Br bonds, and two carbocycles can be established in a single reaction, this 100% atom-efficient reaction exhibits the advantages of wide substrate scope, high functional group tolerance, and step-economics, and it offers an entry of the atom transfer radical addition/cyclization (tandem ATRA-ATRC) process to the synthesis of substituted cyclopentenes.