Cross‐Coupling Reaction of Dimer‐Derived Persistent Tertiary‐Carbon‐Centered Radicals with Azo Compounds

Cross‐coupling reactions using tertiary carbon‐centered radicals are an important class of transformations for constructing C(sp3)−C(sp3) bonds, but the use of dimers as precursors of the persistent radicals is quite rare. Herein, we describe a radical‐based cross‐coupling reaction between dimers (prepared from 2‐oxindoles and benzofuranones) and azo compounds that proceeds simply upon heating the reaction mixture. We present a conformational analysis of the dimers and we characterize the generation of a persistent radical via cleavage of the elongated C(3)−C(3’) σ‐bond. The behavior of the dimers in solution was characterized by spectroscopic analysis, helping to provide a basis for expanding the substrate scope of the cross‐coupling reaction. Two radicals: A cross‐coupling reaction of azo compounds with dimers having an elongated C−C bond as precursors of tertiary carbon‐centered radicals is presented. The reaction affords efficient access to structurally complex heterocycles having vicinal all‐carbon quaternary centers. Spectroscopic analyses provided insight into the mechanism of the radical‐radical cross‐coupling.