Acyl-1,4-Dihydropyridines: Universal Acylation Reagents for Organic Synthesis

Acyl-1,4-dihydropyridines have recently emerged as universal acylation reagents. These easy-to-make and bench-stable NADH biomimetics play the dual role of single-electron reductants and sources of acyl radicals. This review article discusses applications of acyl-1,4-dihydropyridines in organic synthesis since their introduction in 2019. Acyl-1,4-dihydropyridines, activated by photochemical, thermal or electrochemical methods, have been successfully applied as radical sources in multiple diverse organic transformations such as acyl radical addition to olefins, alkynes, imines and other acceptors, as well as in the late-stage functionalisation of natural products and APIs. Release of acyl radicals and an electron can be performed under mild conditions-in green solvents, under air and sunlight, and without the use of photocatalysts, photosensitizers or external oxidants-which makes them ideal reagents for organic chemists.