Oxidation of Aldehydes to Carboxylic Acids with Hydrogen Peroxide and PTSA Catalyzed by β-Cyclodextrin

Abstract

Carboxylic acids are widespread in nature and have broad applications in organic chemistry, pharmaceutical industry, material science, and bioorganic chemistry. Regarding their great significance in organic synthesis, numerous protocols for their preparations have been developed.1 Traditionally, conversion of aldehydes to the corresponding carboxylic acids has been accomplished by assistance of transition metal based strong oxidants such as Jones reagent,2 oxone, potassium permanganate,3 [Ni(acac)2], 4 Pd/C,5 and bismuth(III) nitrate pentahydrate.6 Other metal-free oxidants were also reported which include oxone,7 CO2/coenzyme thiamine pyrophosphate,8 and O2/porphyrin sensitizers. 9 Among other oxidants, hydrogen peroxide received great attention for the oxidation of aldehydes owing to its environmentally benign property to produce water as by product together with its cost effective advantage. For examples, hydrogen peroxide has been successfully mediated aldehyde oxidation oxida-tions in combination with a variety metallic reagents such a