Palladium-Catalyzed ortho-Selective C—H Borylation of 2-Phenylpyridine and Its Derivatives at Room Temperature

摘要

Direct C—H bond transformations have received much attention as ideal and highly efficient methods for the synthesis of useful organic compounds. However, several difficulties remain, in particular the issue of regioselectivity. To solve this problem, directing groups bearing the unshared electron pair of a heteroatom have been used, resulting in dramatic development of the chemistry of C—H bond transformations over the last few decades. The directing group usually acts as a Lewis base to coordinate a transition metal, and thus, the metal center comes close to an appropriate site (a C—H bond) for the reaction, and subsequent C—H activation occurs (Scheme la).