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

The PdII-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.