Synthesis of Benzoic Acids by Aerobic Photooxidation with Hydrobromic Acid

Abstract

A methyl group at an aromatic nucleus is oxidized directly to the corresponding carboxylic acid in the presence of molecular oxygen and catalytic hydrobromic acid under photoirradiation.

aerobic - benzoic acid - hydrobromic acid - methyl group - photooxidation

References

1 Comprehensive Organic Transformations: A Guide to Functional Group Preparations   Larock RC. Wiley-VCH; New York: 1999. 

2 Itoh A. Hashimoto S. Kodama T. Masaki Y. Synlett  2005,  2107 

3 Photooxidation of alkylbenzene in the presence of hydrobromic acid under oxygen has been previously reported; however, the corresponding carboxylic acids were obtained in very low yields, see: Nakada M. Fukushi S. Hirota M. Bull. Chem. Soc. Jpn.  1990,  63:  944 

4

A trace amount of 4-tert-butylbenzyl bromide was detected in the reaction mixture when 1 was used as a substrate.