Oxidative Alkylarylation of N-Aryl Bicyclobutyl Amides with C(sp3)–H Feedstocks via C(sp3)–H/C(sp2)–H Functionalization

The difunctionalization of bicyclo[1.1.0]butanes is an under-explored transformation that accesses to moieties that are otherwise difficult to prepare. Herein, a new oxidative radical alkylarylation of N-aryl bicyclobutyl amides with C(sp³)−H feedstocks is achieved in an atom-economic and photocatalyst- and light-free manner. This protocol follows a sequential C(sp³)–H/C(sp²)–H functionalization, providing an efficient route for diversity-oriented synthesis of functionalized 3-spirocyclobutyl oxindoles. In particular, a wide range of C(sp³)−H feedstocks, including ether, alcohol, amine, thioether, polychlorinated methane, silane, acetone, acetonitrile, toluene, and alkane are all suitable for the C(sp³)−H functionalization, demonstrating the broad applicability of this transformation.