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Diazohydroxides, Diazoethers and Related Species

Hydroxylamines, Oximes and Hydroxamic Acids (2010)

  1. Carlos D. Bravo-Díaz

Published Online: 15 OCT 2010

DOI: 10.1002/9780470682531.pat0511

Patai's Chemistry of Functional Groups

Patai's Chemistry of Functional Groups

How to Cite

D. Bravo-Díaz, C. 2010. Diazohydroxides, Diazoethers and Related Species. Patai's Chemistry of Functional Groups. .

Author Information

  1. Universidad de Vigo, Fac. Química, Dpto. Química, Física, Vigo, Pontevedra, Spain

Publication History

  1. Published Online: 15 OCT 2010


Arenediazonium, ArN2+, ions may function as Lewis acids reacting with nucleophiles (Lewis bases, Nu or NuH followed by loss of a proton) to give covalently bonded adducts, ArN2-Nu, at the β-nitrogen of the arenediazonium ion, which is the electrophilic reactive center. Typical examples of covalently bonded adducts are the azo dyes (C-coupling) but atoms other than C may be involved and the present chapter will mainly focus on the chemistry of O-coupling adducts of the type ArN=N-Nu, e.g., where Nu = OH (formation and decomposition of diazohydroxides and diazoates), Nu = RO, ArO, ROH and cyclodextrins (formation and decomposition of diazoethers), with special emphasis on the kinetics and mechanism of the reactions involved. We will also cover, to a lower extent, those reactions with other nucleophiles leading to S-, N- and P-adducts. O-coupling reactions are complicated by two major features. First, the formed adducts may display geometrical isomerism, leading to the E-(syn) and Z-(anti) forms, which show different stability and can be interconverted to each other by acid catalyzed processes. Second, some of the O-adducts formed may be, in turn, components of a Lewis acid-base equilibrium, for example between ArN2+ and OH ions, and hence may undergo further reactions.


  • diazo compounds;
  • diazohydroxide;
  • diazoate;
  • diazoether;
  • arenediazonium;
  • heterolytic mechanism;
  • homolytic mechanism;
  • aryl radicals