Recent Advances in the Chemical Synthesis of β-Nicotinamide Mononucleotide

β-Nicotinamide mononucleotide (β-NMN), a key precursor in the biosynthesis of nicotinamide adenine dinucleotide (NAD+) in mammals, has significant effects in replenishing NAD+ levels in the body, so it has obvious ameliorative effects on metabolic and age-related degenerative diseases. β-NMN is widely used in healthcare products, food, and cosmetics. It has considerable commercial worth and promising medical application prospects. Hence, the development of methods for preparing β-NMN is of great research significance. This review summarized and analyzed recent developments in the chemical synthesis of β-NMN from various starting materials, which could provide helpful references for the investigation of new synthetic techniques for β-NMN and encourage its further development and large-scale application.