Pyridine-Boryl Radical-Mediated Dehalogenative Pyridylation Reaction for the Construction of Pyridylated Tri- and Tetrarylmethanes.

We herein report an organic base-promoted radical dehalogenative coupling of benzylic halides with 4-cyanopyridine. Using tBuOLi or DABCO, a range of diarylmethyl- and triarylmethyl-substituted C4-pyridines are obtained with broad functional group tolerance. Mechanistic studies, including DFT calculations, reveal that the base coordinates to the pyridine-boryl radical, lowering the activation barrier of the rate-limiting debromination step and thereby facilitating efficient C4-pyridylation.