Nickel-catalyzed oxidative cross-coupling of arylboronic acids with olefins

A novel and efficient nickel-catalyzed oxidative cross-coupling of arylboronic acids with olefins to synthesize 1,2-diarylalkenes has been developed. By employing Ni(acac)(2) as the catalyst, TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl) as the oxidant, a variety of arylboronic acids and styrene derivatives could be cross-coupled efficiently to afford the corresponding 1,2-diarylalkenes in moderate-to-good yields. Notably, high E-selectivity of 1,2-diarylalkenes was obtained with the aid of a high temperature of 120 degrees C. Moreover, boric acid esters also proved to be efficient coupling partners. Initial mechanistic studies suggest that this reaction proceeds through a radical pathway.