Recent Advances in Catalytic Nitrogen–Nitrogen Bond Formation Reactions

The lack of effective strategies for direct construction of nitrogen–nitrogen bonds has hampered developments in the synthesis and application of molecules containing hydrazine or azo motifs. Attracted by their properties both in material science and in medicinal chemistry, more and more attention has been drawn to this area, resulting in fast growth in the design and synthesis of azaheterocycles and substituted hydrazines. This review focuses on efficient catalytic approaches toward the formation of N–N and N═N bonds through different strategies, including oxidative dehydrogenation, nitrene-transfer reaction, reductive coupling, and some other recently developed methods.