V(IV)-catalyzed cyclohexane oxygenation promoted by oxalic acid: Mechanistic study

Abstract Study the mild cyclohexane oxygenation using vanadyl(IV)acetylacetonate as the starting catalyst and H 2 O 2 as the oxidant has shown that oxalic acid as activator alters the products ratio, increases yield and catalyst turnover number. According to the instrumental (ESI-MS, NMR, EPR, UV–vis, GC, pH, titrimetric) investigations both the parental VO( acac ) 2 and originated in situ vanadyl(IV)oxalate can consequently interact with H 2 O 2 led, among others, to intermediates comprise VO(η 2 -O 2 ) metal core. Such vanadium-peroxo species manifest itself as the additional oxygenation agent which generation is inspired by oxalic acid additives. The enhanced aimed products yield and improved process selectivity revealed in the presence of oxalic acid may be stipulated with these non-radical intermediates.