Related Experiment Video
Updated: Jun 24, 2026

Preparation of 6-aminocyclohepta-2,4-dien-1-one Derivatives via Tricarbonyl(tropone)iron
Published on: August 12, 2019
"Pulling-Out" N2 from Diazo Compounds by Iron Complex for Carbene Formation
Yun-Shu Cui1, Hong-Yu Cheng1, Xu-Zhou Li1
1Department of Chemistry, Fudan University, Shanghai 200438, China.
None:
One of the main pathways to (metal)carbene formation proceeds via the decomposition of diazo compounds, which can be triggered thermally, photochemically, or by transition-metal mediation. An alternative pathway for carbene generation from diazo compounds is the "pulling-out" N2 by different reagents. Herein, we report an iron-mediated strategy for the homolytic cleavage of C═N bond in diazo compounds, enabling the generation of free carbenes and iron-dinitrogen complexes under mild conditions. The corresponding Fe-diazo intermediates were isolated and fully characterized by X-ray crystallography and NMR spectroscopy. Homolytic C-N bond cleavage occurs upon warming, affording a persistent (phosphino)(silyl)carbene. The kinetics of this process were further elucidated by Eyring analysis. Computational modeling highlighted the critical role of Fe → N π-backdonation in cleaving the C═N π bond. These findings establish a new mechanistic framework for metal-assisted dinitrogen extrusion from diazo compounds and offer valuable insights into controlled carbene generation.
Related Concept Videos
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
Nucleophilic Aromatic Substitution: Elimination–Addition
Diazonium Group Substitution: –OH and –H
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction

