NADH and Nonnatural Dihydronicotinamides (NAH) as Reagents in Organic Synthesis and Catalysis

NADH is a universal redox cofactor in life. NADH and synthetic N ‐substituted 1,4‐dihydronicotinamides (NAHs) are versatile hydride, hydrogen‐atom, and electron donors, with diverse applications in nonenzymatic chemistry. This review surveys the historical development and modern applications of NADH and related NAHs as reagents in organic synthesis, spanning polar hydride‐transfer and radical pathways, including SET and HAT processes, as well as emerging applications in complex biological environments. Overall, these developments highlight the potential of dihydronicotinamides as versatile, inherently biocompatible reagents beyond their traditional roles in biology.