Research news, Dec. 23rd, 2014

 Mechanistic Insights into N–N Bond Cleavage in Catalytic Guanylation Reaction between 1,2-Diarylhydrazines and Carbodiimides

Ling Xu, Yu-Chen Wang, Wangyang Ma, Wen-Xiong Zhang,* and Zhenfeng Xi*

J. Org. Chem. 2014, 79, 12004-12009. 

(Special Issue: Mechanisms in Metal-Based Organic Chemistry)

Cleavage of the N–N bond in 1,2-diaryl hydrazines was achieved in alkyl lithium-catalyzed guanylation reaction of 1,2-diarylhydrazines with carbodiimides, affording guanidines and azo compounds. This N–N bond cleavage via thermal rearrangement was driven by the intramolecular proton shift. No reductants, oxidants, bases and external protons were needed. The proposed mechanism was well elucidated by the isolation, characterization and reaction study of two important amido lithium intermediates and the ArHN-substituted guanidine.