Direct photochemical route to azoxybenzenes via nitroarene homocoupling
Ali Yaghoubian1, Gregory K Hodgson1, Marc J Adler1
1Department of Chemistry and Biology, Toronto Metropolitan University, 350 Victoria St, Toronto, ON, M5B 2K3, Canada. marcjadler@ryerson.ca.
Abstract:
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.
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