Ambiphilic cross-coupling

Cross-coupling reactions traditionally permit the formation of Ar‒Ar bonds between an aryl nucleophile and an aryl electrophile under transition metal catalysis. The high selectivity of the myriad of couplings known to date relies on a tailored combination of nucleophilic and electrophilic coupling partners. Here, we report ambiphilic aryl-bismuth reagents that can behave as either nucleophiles or electrophiles in transition metal–catalyzed cross-couplings, fundamentally breaking from this dichotomy in polarity. Their ambiphilic reactivity arises from their ability to engage in both oxidative addition and transmetalation processes with transition metal complexes, as demonstrated by stoichiometric and mechanistic studies. This concept redefines the paradigm of cross-coupling, shifting polarity control from the reagent to the catalytic strategy and providing a new blueprint for synthetic design.