Rhodium-Catalyzed Decarbonylative Direct Olefination of Arenes with Vinyl Carboxylic Acids

A rhodium(I)-catalyzed direct C-H bond olefination of pyridyl-substituted arenes with readily available vinyl carboxylic acids has been realized. This reaction occurred efficiently without the need for any external oxidant, affording the ortho-olefinated products in high yields and excellent regioselectivities. Diversely substituted vinyl carboxylic acids behaved as efficient olefination reagents under the reaction conditions, and a range of functional groups in both coupling partners was well tolerated. Mechanistic studies indicated that a decarbonylation step is involved in this catalytic process, and pivalic anhydride [(t-BuCO)(2)O] acts as the activator of the carboxylic acids for the in situ generation of highly active anhydrides.