New Trends in Palladium‐Catalyzed Transfer Hydrogenations Using Formic Acid

Abstract In the presence of a catalytic amount of organic bases, Pd‐catalyzed transfer hydrogenations with formic acid were found to be facile processes. These new conditions produce innocuous carbon dioxide as the by‐product compared to the use of ammonium formate, which generates ammonia and carbon dioxide as gaseous by‐products which recombine to create unsafe conditions. When the substrate is basic enough to form salts with formic acid, no additional base is necessary. In certain cases, the product of the reaction was used to accelerate the transfer hydrogenation process.