Direct Photochemical Route for Amine- and Catalyst-Free Synthesis of Azoxybenzene and Functional Azoxy Derivatives via Accessible Nitroarene Homocoupling under Ambient Conditions

16 May 2022, Version 1
This content is an early or alternative research output and has not been peer-reviewed by Cambridge University Press at the time of posting.


We report on a direct photochemical method for the one-pot, catalyst- and additive-free synthesis of azoxybenzene and substituted azoxy derivatives from nitrobenzene building blocks. This reaction is conducted at room temperature and under air, and can be applied to substrates with a wide range of substituents. Yields of products derived from para- and meta-substituted nitrobenzenes are typically good, while sterically encumbered ortho-substituted substrates are not as fruitful. Photochemical Wallach rearrangement of generated azoxybenzenes to ortho-hydroxyazoxybenzenes was observed in some cases, most markedly in selected ortho-halogenated nitrobenzenes. Overall, this method provides an efficient, green pathway to highly value-added azoxybenzene products.


Nitrobenzene reduction
Nitrobenzene photochemistry
Wallach reaction

Supplementary materials

Supplementary Information
Absorption Spectra. 1H NMR, 13C CMR and GC-MS data.


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