Atroposelective NiII‐Catalyzed Cross‐Coupling Reactions Enable a Deeper Understanding of Negishi Couplings: Isolation and Application of Solid Aryl Higher‐Order Zincates

Abstract

AbstractThe Negishi cross‐coupling reactions involves the application of organozinc reagents and is a highly versatile reaction in synthetic organic chemistry. The transmetallation step plays a pivotal role in the mechanism of these types of cross‐coupling reactions. In this study, mechanistic investigations are presented indicating that higher‐order zincates are the transmetallating active species in Pd‐ and Ni‐catalyzed Negishi cross‐coupling reactions. These findings are supported by halide salt addition experiments and by obtaining a single X‐ray crystal structure of the solid monoaryl higher‐order zincate [1‐NaphthylZnX3]2−Mg(THF)22+. The procedure developed in this work was further applied to the synthesis of various monoaryl higher‐order zincates, after which their synthetic usefulness in terms of high reactivity towards transmetallation in Negishi cross‐couplings, as well as stability, was exemplified in several reactions.