Copper-Catalyzed Intermolecular Cyclopropanation of Benzofurans and Indoles

) to form a putative metal carbenoid that gives a productive dearomative reaction with substituted benzofurans and Cbz-protected indoles. The use of Cu(II) represents a shift toward more sustainable earth-abundant metal catalysts relative to the more common Rh(II)-based catalysts in Buchner cyclopropanations. This work serves as a foundation for further investigation into the use of earth-abundant metals for dearomative chemistry.