Synthetic and biosynthetic routes to nitrogen–nitrogen bonds

The nitrogen–nitrogen bond is a core feature of diverse functional groups like hydrazines{,} nitrosamines{,} diazos{,} and pyrazoles. Such functional groups are found in >300 known natural products. Such N–N bond-containing functional groups are also found in significant percentage of clinical drugs. Therefore{,} there is wide interest in synthetic and enzymatic methods to form nitrogen–nitrogen bonds. In this review{,} we summarize synthetic and biosynthetic approaches to diverse nitrogen–nitrogen-bond-containing functional groups{,} with a focus on biosynthetic pathways and enzymes.