Pretransmetalation Intermediates in Suzuki–Miyaura Cross-Couplings: Synthesis of Csp3-, Csp2- and Csp-Organopalladium(II) Boronates

Organopalladium(II) boronates represent fundamental pretransmetalation intermediates in Suzuki–Miyaura cross-couplings. These species are typically kinetically unstable, making them particularly elusive. In this study, a range of unprecedented, kinetically stable alkyl-, alkenyl-, allenyl-, and alkynylpalladium(II) boronates were prepared from various C sp 3, C sp 2, and C sp electrophiles via a simple, general method. The structures of these complexes were secured by X-ray crystallography, and the chemical competence of a number of these intermediates in transmetalation was demonstrated.