Iron-catalyzed Alkyl–Alkyl Negishi Coupling of Organoaluminum Reagents

The first iron-catalyzed cross-coupling reaction of alkyl halides with alkylaluminum reagents (alkyl–alkyl Negishi coupling) is developed using an iron/bisphosphine catalyst system. The reaction shows high functional group tolerance: various primary alkyl halides possessing a non-protected indole, carboxyl, or hydroxy group are coupled with primary alkylaluminum reagents in good yields. Potassium fluoride plays a key role to promote the reaction by generating an aluminate species, which facilitates the transmetalation between the organoaluminum and the iron catalyst.