A General and Efficient Method for the Formylation of Aryl and Heteroaryl Bromides

The key to the general and efficient palladium-catalyzed formylation of aryl and heteroaryl bromides is the use of the di-1-adamantyl-n-butylphosphane (cataCXium A) as ligand. Low pressure of the synthesis gas and appropriate choice of the base are also important for high yields (up to 99 %) of a broad range of (hetero)aromatic aldehydes at unprecedented low catalyst concentrations (see scheme; TMEDA= N,N,N′,N′-tetramethylethylenediamine).