Visible-light-initiated one-pot clean synthesis of nitrone from nitrobenzene and benzyl alcohol over CdS photocatalyst

• Published in: Journal of catalysis Vol. 370; pp. 97 - 106
• Main Authors: Yu, Weiwei, Guo, Xinwen, Song, Chunshan, Zhao, Zhongkui
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.02.2019
• Subjects: Clean synthesis; Imine and secondary amine; Nitrobenzene and benzyl alcohol; Nitrone; One-pot strategy; Photocatalysis; Imine and secondary amine; Clean synthesis; Nitrobenzene and benzyl alcohol; Nitrone; Photocatalysis; One-pot strategy
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2018.12.011

[Display omitted] •A facile visible-light-initiated strategy is presented for nitrone clean synthesis.•Photocatalytic nitrobenzene selective reduction to phenylhydroxylamine is realized.•Integrating effect of the reduction-oxidation half-reactions promotes the process.•91% nitrone selectivity at 77% conversion is achieved by only 25-30 min irradiation.•Imine or secondary amine is achieved by tuning cocatalyst and illumination time. The controlled visible-light mediated conversion of nitroaromatics to versatile nitrogen-containing intermediates is of great significance but still remains a challenge. Herein, we report for the first time a facile visible-light-initiated one-pot strategy for clean and efficient synthesis of nitrone from nitrobenzene and benzyl alcohol. It integrates the controlled photocatalytic reduction of nitrobenzene to phenylhydroxylamine by photogenerated electrons with the selective photocatalytic oxidation of benzyl alcohol to benzaldehyde by photoinduced holes over a low-cost CdS photocatalyst with a suitable reduction capability, followed by spontaneous condensation of the as-formed hydroxylamine and aldehyde at ambient pressure and room temperature. Furthermore, by modulating cocatalyst and illumination time, for the conversion of the same reactants, the other two useful nitrogen-containing compounds, imine and secondary amine, were also successfully synthesized. The reaction mechanisms for flexible synthesis of the three target products are proposed.