Peroxovanadium-Catalyzed Oxidative Esterification of Aldehydes

Abstract

The peroxovanadium species generated from V(2)O(5) and hydrogen peroxide, which is liberated from peroxy salts such as sodium perborate (SPB) or sodium percarbonate (SPC), transform aldehydes directly into esters in an alcoholic medium. Monoesters of diols have been achieved directly in one pot from aldehydes. High catalytic turnover number combined with inexpensive, easily available reagents and innocuous side products from the reaction make it a suitable alternative for the synthesis of esters from aldehydes.

Oxidative esterification of alcohols and aldehydes using supported iron oxide nanoparticle catalysts

“…Another route for this synthesis is via direct oxidation of an aldehyde in the presence of an alcohol to produce an ester. In the past, this organic reaction is usually performed using a ruthenium catalyst [9], vanadium oxide [10,11], and copper [12]. The primary mechanism of the reaction involves the formation of the hemiacetal intermediate upon reaction with the alcohol -this reaction is mediated by the presence of the metal acting as a Lewis acid that chelates with the carbonyl oxygen.…”

N-Heterocyclic carbene-catalyzed oxidations

“…Recently, pyridinium hydrobromide perbromide,20 peroxides,21,22 and Oxone23 have all been reported to function as oxidants in these transformations. These approaches can suffer from toxic or expensive reagents as well as non-selective oxidation of the alcohol that serves as the nucleophile.…”

N-Heterocyclic Carbene-Catalyzed Oxidation of Unactivated Aldehydes to Esters

“…These advantages have inspired numerous investigations into the direct oxidation of aldehydes to esters 3. Recent methods have employed Oxone,4 pyridinium hydrobromide perbromide,5 or peroxides6 as oxidants, but these approaches can suffer from toxic or expensive reagents or competing oxidation of the alcohol nucleophile. The less efficient two-step process involving the oxidation of the aldehyde to a carboxylic acid and subsequent alkylation can be significantly complicated by over-oxidation of electron-rich aromatic rings and chemoselectivity issues during the alkylation step.…”