Formylation of Aryl Halides with Carbon Monoxide and Sodium Formate in the Presence of Palladium Catalyst

Abstract The formylation of aryl bromides or iodides with HCOONa at atmospheric pressure of CO readily proceeded in the presence of PdCl2(PPh3)2 in DMF to afford the corresponding aldehydes in good yields. The contamination with water promoted a side reaction to form carboxylic acids. The formylation using HCOOK or HCOONH4 as a hydride source was fast but gave a considerable amount of the reduction product.