Nickel-catalyzed Reaction Of Aryl Iodides And Formates For The Preparation Of Aromatic

As a very important chemical product,aromatic carboxylic acid is a common structure in many natural products,medicines and agricultural chemicals.At present,the preparation of most aromatic acids is usually through multi-step reactions or oxidation reactions,which has many shortcomings.The synthetic method of aromatic carboxylic acids from aryl iodide is often through palladium-catalyzed carbon monoxide intercalation reaction,which is highly toxic and difficult to operate in experiments,and is limited in laboratory research and industrial applications.Therefore,it is important to develop carbonylation reactions involving carbon monoxide substitutes.At present,the main substitutes for carbon monoxide are:formic acid and its derivatives,aldehydes,metal carbonyl compounds,carbamoyl silane and carbamoyl stannane.Among them,formic acid is a non-toxic,cheap and renewable liquid,which is an ideal raw material for the construction of carbonyl units.Therefore,formic acid has been used in various transition metal-catalyzed carbonylation reactions as a carbonylation reagent.We use formate to replace carbon monoxide gas,cheap nickel catalyst combined with bidentate phosphine ligand,to develop hydrocarboxylation of aryl iodides under mild conditions,and provide a new method for preparing various types of aromatic carboxylic acids.This protocol exhibits remarkable functional group tolerance,including typical functional groups commonly used in cross-coupling reactions(eg,aryl bromide,aryl chloride,aryl tosylate and aryl pinacol borate).Compatibility,a variety of functional aromatic carboxylic acids,including some nitrogen-containing heterocyclic products(nicotinic acid derivatives,pyridine,etc.)and drug molecules(estrone)post-modification can be successfully obtained through this method.In the presence of acetic anhydride and lithium formate,the reaction system generates carbon monoxide in situ to avoid the use of high-pressure gaseous carbon monoxide.The combination of the bidentate phosphine ligand and the catalytic amount of carbon monoxide cycle are the keys to the successful conversion of this reaction.