Oxidation of the Methyl Group at the Aromatic Nucleus with Molecular Oxygen­ in the Presence of N-Bromosuccinimide under Photoirradiation

Abstract

A methyl group at the aromatic nucleus can be oxidized to the corresponding carboxylic acid directly in the presence of N-bromosuccinimide (NBS) under photoirradiation. By considering both the promoting effect of oxygen and a catalytic amount of NBS, aerobic oxidation via hydroperoxide, which is thought to be generated by abstraction of a hydrogen with a bromo radical from NBS, proceeded.

oxidations - methyl group - N-bromosuccinimide - photoirradiation - molecular oxygen

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6

The corresponding aldehydes (6-7%) and inseparable products were formed, respectively.

7

4-tert-Butylbenzaldehyde was oxidized to 2 in 93% yield under the same reaction conditions.