Palladium-catalyzed carbonylation reactions for late-stage functionalization of privileged heterocyclic scaffolds

Abstract

Over the last decades, carbon monoxide (CO) has been widely used as a relevant and versatile anchor in several synthetic processes, namely carbonylations. These reactions cover olefin hydroformylation, amino- and alkoxycarbonylation of aryl halides, carbonylative transformations of alkenes and alkynes, carbonylative cross-coupling reactions, and oxidative C‒H carbonylation. Palladium-mediated carbonylations have been remarkably expanded since the discoveries of Heck- and Sonogashira-type carbonylation reactions which represent landmarks for palladium catalysis. At present, carbonylative cross-coupling reactions represent a versatile method for direct transformation, late-stage functionalization, isotopic carbon labeling, and chain elongation, leading to organic compounds containing one or more carbonyl groups such as amides, imides, carbamates, aldehydes, ketones, carboxylic acids, esters, etc. Interestingly, carbonylation of C(sp2)‒X bond, such as vinyl and aryl halides (or pseudohalides), is another important development in broadening the substrate scope. In addition, employing various nucleophiles such as alcohol, and amines further diversifies the product library. Particularly, palladium catalyzed carbonylations of (hetero)aryl halides have garnered extensive attention for C‒C bond formation and constitute an important branch.