Cobalt-catalyzed addition of styrylboronic acids to 2-vinylpyridine derivatives.

Treatment of 2-vinyl nitrogen-containing heteroaromatic compounds with styrylboronic acid in the presence of a cobalt catalyst and a base results in an addition reaction to afford the corresponding 4-phenyl-3-butenyl heteroarenes. The adjacent nitrogen atom is essential for the promotion of the reaction because the nitrogen accelerates the addition of the styryl cobalt species, generated by transmetalation, onto the vinyl group. The reaction represents a rare example of cobalt catalysis in the reactions of organoboronic acids.