Visible-Light-Promoted Iron-Catalyzed C(sp2)-C(sp3) Kumada Cross-Coupling in Flow

A continuous-flow, visible-light-promoted method has been developed to overcome the limitations of iron-catalyzed Kumada-Corriu cross-coupling reactions. A variety of strongly electron rich aryl chlorides, previously hardly reactive, could be efficiently coupled with aliphatic Grignard reagents at room temperature in high yields and within a few minutes' residence time, considerably enhancing the applicability of this iron-catalyzed reaction. The robustness of this protocol was demonstrated on a multigram scale, thus providing the potential for future pharmaceutical application.