Diversified Synthesis of All-Carbon Quaternary gem-Difluorinated Cyclopropanes via Copper-Catalyzed Cross-Coupling

The construction of all-carbon quaternary centers in small-ring systems is important but challenging in organic synthesis. Herein, by taking gem-difluorocyclopropyl bromides (DFCBs) as a type of general and versatile building block, we developed a practical method for building all-carbon quaternary centers in gem-difluorinated cyclopropanes (DFCs). The reaction relies on the involvement of a gem-difluorocyclopropyl radical intermediate, which can couple with a wide range of nucleophiles under copper catalysis.