Oxidative C–C Bond Functionalization of Methylenecyclopropanes with Aldehydes for the Formation of 2‑Acyl-3,4-dihydronaphthalenes

A new FeCl2- and DTBP (di-tert-butyl peroxide)-promoted oxidative ring-opening and cyclization of methylenecyclopropanes with aldehydes for the synthesis of 2-acyl-3,4-dihydronaphthalenes is presented. This oxidative cyclization reaction proceeds via a radical addition, ring-opening, and cyclization sequence facilitated by a Lewis acid, and it offers a practical and straightforward route for the oxidative cyclization of methylenecyclopropanes with an aromatic carbon and a C­(sp2)–H bond by simultaneously forming two new carbon–carbon bonds.