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

Comprehensive Summary 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(sp 3 )−H feedstocks is achieved in an atom‐economic and photocatalyst‐ and light‐free manner. This protocol follows a sequential C(sp 3 )–H/C(sp 2 )–H functionalization, providing an efficient route for diversity‐oriented synthesis of functionalized 3‐spirocyclobutyl oxindoles. In particular, a wide range of C(sp 3 )−H feedstocks, including ether, alcohol, amine, thioether, polychlorinated methane, silane, acetone, acetonitrile, toluene, and alkane are all suitable for the C(sp 3 )−H functionalization, demonstrating the broad applicability of this transformation.