Formation of Complex Hydrazine Derivatives via Aza-Lossen Rearrangement

The development of a broadly applicable procedure for the aza-Lossen rearrangement is reported. This process converts amines into complex hydrazine derivatives in two steps under safe, mild conditions. This method allows the chemoselective formation of N–N bonds, resulting in the synthesis of cyclic and acyclic products while avoiding side reactions of the amphoteric (ambident) nitrogen-substituted isocyanate intermediate.