Work

Diboron Reagents in N−N Bond Cleavage of Hydrazines, N ‐Nitrosamines, and Azides: Reactivity and Mechanistic Insights

Year: 2025

Type: article

Abstract: Diboron reagents are known for their ability to promote the deoxygenation of amine or pyridine oxides, nitroarenes, and nitrones through the formation of B−O−B bonds. In this study, we have investigated the potential of diboron reagents to induce N−N bond cleavage in hydrazines, N ‐nitrosamines and azides. Our findings show that the combination of B 2 nep 2 as diboron source and KOMe as a Lewis base can effectively promote the N−N cleavage of a wide variety of substrates. For hydrazines and nitrosamines, the presence of an aryl group is essential for the reaction to proceed, probably due to a better stabilization of the negative charge developed during N−N bond cleavage. Both types of azides, aromatic and aliphatic, are easily reduced, and the resulting amines can be in situ converted into the corresponding amides by simple treatment with a carboxylic acid. Experimental and theoretical calculations suggest a non‐radical mechanism, with concerted B−B and N−N bond cleavage in the case of hydrazines and azides, and a stepwise mechanism in the case of N‐ nitrosamines, where deoxygenation occurs as the first step, involving the formation of an N ‐nitrene intermediate.

Source: Chemistry - A European Journal

DOI: 10.1002/chem.202404081

Authors: Raúl Valderrama‐Callejón, Emily L. Vargas, Inés Alonso, Mariola Tortosa, Mariola Tortosa, M. Belén Cid

Institutions: Universidad Autónoma de Madrid, Universidad de Costa Rica, ORFEO-CINQA Research Network

Language: English

Topic: Organoboron and organosilicon chemistry

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,640

Funder: Universidad de Costa Rica