Carbon monoxide as the key: carbonylation triggered (hetero)aryl migration transformations

This review summarizes recent advances in carbonylative functionalization strategies enabled by free radical mediated carbon monoxide (CO) insertion, with a focus on its role in facilitating carbon chain elongation and activating challenging allylic alcohol substrates via radical-mediated migration reactions. The article systematically discusses a range of radical triggers-including CF₃, diazo-derived, oxygen-centered, trifluoromethylthio, alkoxycarbonyl, phosphinyl, nitrogen-centered, cobalt-hydride, and hydrogen-bonding-assisted species-that promote intermolecular and intramolecular functional group migrations under mild conditions. Key to these transformations is the synergistic interplay between CO insertion and migration events, which collectively enable remote aryl or heteroaryl transfer to carbonyl carbons, yielding valuable 1,4-dicarbonyl compounds, lactones, and other functionalized scaffolds. The review also highlights mechanistic insights, substrate adaptability, and the ability to overcome traditional limitations in selectivity and reactivity. Despite significant progress, challenges remain in expanding migration scope, simplifying substrate design, and achieving asymmetric catalysis. This work aims to inspire further innovation in CO-mediated synthetic methodologies.