Transition Metal-Free Radical α-Oxy C−H Cyclobutylation via Photoinduced Hydrogen Atom Transfer

A transition-metal-free photoinduced radical-mediated α-oxy C−H cyclobutylation reaction of bicyclo[1.1.0]butane (BCB) compounds was described. In this protocol, α-oxy C(sp³)−H motifs including ethers and alcohols were activated via photocatalytic conditions, releasing the ring strain of BCBs and generating 1,3-disubstituted cyclobutanes in 40–80% yields. Control experiments and Stern-Volmer quenching experiments indicated that the reaction proceeded through the generation of α-oxy carbon-centered radical intermediates by photoinduced hydrogen atom transfer (HAT) process. (Figure presented.).