Palladium-Catalyzed Formylation of Aryl Iodides with HCOOH as CO Source

A facile and practical method for the synthesis of aromatic aldehydes by palladium-catalyied reductive carbonylation starting from aryl iodides and HCOOH is described. Compared to the known formylation procedure, HCOOH serves not only as the most Convenient and environmental friendly Cl source but also as the reviving agent in the reductive elimination process of Pd-catalyst. Furthermore, this procedure is also apPlied successfully to modifitation of natural prochicts, such as vindoline, tabersonin, and viricamine, to obtain the corresponding products in good yields.