Unraveling two pathways for NHPI-me diate d electrocatalytic oxidation reaction

Two pathways for N-hydroxyphthalimide (NHPI)-mediated electrocatalytic oxidation using phenylacetate derivatives as template substrates were first reported for benzylic C-H oxidation to oxygenated and non oxygenated products. DFT calculation indicates that the hydrogen-atom transfer (HAT) process between phthalimido-N-oxyl (PINO) and substrate is a rate-determined step. Aromatic alpha-keto esters and 2-((1,3dioxoisoindolin-2-yl)oxy)-2-aryl acetate obtained by cross-coupling between benzylic radical and PINO can be selectively synthesized through controlling the concentration of PINO radical. This method provides a deep understanding for selective weak C -H oxidation using NHPI as redox mediator. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study reports for the first time two pathways for N-hydroxyphthalimide (NHPI)-mediated electrocatalytic oxidation using phenylacetate derivatives as template substrates, achieving benzylic C-H oxidation to oxygenated and non oxygenated products. The rate-determined step was found to be the hydrogen-atom transfer (HAT) process between phthalimido-N-oxyl (PINO) and substrate, as indicated by DFT calculation. By controlling the concentration of PINO radical, selective synthesis of aromatic alpha-keto esters and 2-((1,3dioxoisoindolin-2-yl)oxy)-2-aryl acetate through cross-coupling between benzylic radical and PINO is achieved. This study provides a deep understanding for selective weak C-H oxidation using NHPI as redox mediator.