Palladium-Catalyzed Coupling of Arene C-H Bonds with Methyl- and Arylboron Reagents Assisted by the Removable 2-Pyridylsulfinyl Group

The Pd-II-catalyzed direct coupling of arene C-H bonds with organoboron reagents assisted by the 2-pyridylsulfinyl group is reported. Methylboronic acid and arylboronic acid neopentyl esters proved to be efficient coupling partners, furnishing methylated arenes and biaryl products in moderate to good yields. The 2-pyridylsulfinyl group can be easily removed to provide the free biaryls. The essential role of the 2-pyridyl unit in stabilizing the cyclopalladation complex was demonstrated by X-ray diffraction analysis of the palladacycle intermediate.