Abstract
Covalently tethering a supporting ligand to a boron nucleophile allowed typically elusive, kinetically unstable Suzuki–Miyaura (SM) pretransmetalation species to be tamed. This strategy enabled the synthesis and X-ray crystallographic characterization of an organonickel(II) boronate pretransmetalation intermediate. Performing reactions in the presence of carbon monoxide delivered pretransmetalation intermediates in carbonylative SM reactions–aroylmetal boronates. This enabled the X-ray crystal structure of an aroylnickel(II) boronate (and an aroylpalladium(II) boronate) to be secured.