Regioselective alkenylation of aromatic ketones with alkenylboronates using a RuH2(CO)(PPh3)3 catalyst via carbon-hydrogen bond cleavage

The ruthenium-catalyzed alkenylation of C-H bonds with alkenylboronates has been explored for a series of aromatic ketones. The coupling reaction of pivalophenone (1) with 2-isopropenyl-5,5-dimethyl[1,3,2]dioxaborinane (2) gave the corresponding isopropenylation product in 73% yield. In the case of the reaction of a sterically congested alkenylboronate, such as 2-methylpropenylboronate (8), the yield was decreased slightly. When beta-styrylboronates were used, the corresponding coupling products were obtained in good yields. The reaction of acetophenone with alpha-styrylboronate afforded the corresponding 1:1 coupling product, exclusively.