Single catalyst double outer-sphere alkene cross-coupling
Cross-coupling catalysts typically react and unite functionally distinct partners via sequential inner-sphere elementary steps: coordination, migratory insertion, reductive elimination, etc. Here we report a single catalyst that cross-couples styrenes and benzyl bromides via iterative outer-sphere steps: metal-ligand-carbon interactions. Each partner forms a stabilized radical in-termediate yet hetero-coupled products predominate. The system is redox neutral and thus avoids exogenous oxidant, resulting in simple and scalable conditions. Numerous variations of alkene hydrobenzylation are made possible, including access to the privileged hetero-dibenzyl (1,2-diarylethane) motif and challenging quaternary carbon variants.