Since the discovery of the palladium-catalyzed Suzuki Miyaura reaction, organoboronates have been developed as powerful reagents for carbon-carbon bond formation due to their stability, nontoxicity, and functional group compatibility. Although numerous ligand systems have been developed for a wide array of coupling partners, reaction of electron-deficient boronates such as 2-pyridyl remains challenging2 and of high interest to the synthetic community, particularly the pharmaceutical industry. For example, coupling of 2-pyridylboronic acid was unsuccessful under a very general Suzuki coupling system.
It is hypothesized that transmetalation from boron to palladium of electron-deficient 2-heterocyclic boronates is slow relative to protodeboronation, leading to poor conversions.
In 2009, Deng reported the successful copper(I)-facilitated Suzuki coupling of 2-heterocyclic boronates that is broad in scope; furthermore, mechanistic investigations suggest a possible role of copper in the catalytic cycle.
Org. Lett., Vol. 11, No. 2, 2009
