Metal-Free Oxidative C–C Bond Functionalization of Methylenecyclopropanes with Ethers Leading to 2‑Substituted 3,4‑Dihydronaphthalenes

A novel metal-free oxidative ring-opening/cyclization of methylenecyclopropanes with ethers was established for the synthesis of diverse 2-substituted 3,4-dihydronaphthalenes with high selectivity and efficiency. This oxidative cyclization is achieved by C­(sp3)-H functionalization, ring-opening, and cyclization, and this method represents a new example of methylenecyclopropane oxidative cyclization with an aromatic carbon and a C­(sp3)-H bond by simultaneously forming two new carbon–carbon bonds.