A catalyst-free protocol for direct oxidative esterification of alcohols and aldehydes

N,N-Dibromo-p-Toluenesulfonamide (TsNBr2): A Promising Alternative Bromo-Organic Reagent

“…We found that treatment of an alcohol (1 mmol) with 2.7 equivalents of TsNBr 2 in presence of five equivalents of K 2 CO 3 in a solvent mixture of acetonitrile/methanol (5:1) provided the corresponding methyl ester in a maximum yield of 75-88% (18). 27 Both aromatic and aliphatic alcohols could be transformed into the corresponding esters in moderate to high yields. It has been observed that the rate of the reaction is very fast for benzyl alcohols with a strong electron-withdrawing group, such as nitro.…”

Metal‐free aerobic oxidative esterification of aromatic aldehydes promoted by potassium fluoride (KF)

“…In this methodology, different catalysts have been used, such as copper, nickel, palladium, etc . In addition to the metal‐catalyzed reactions, a literature survey shows that this transformation could be accomplished under metal‐free conditions in the presence of organocatalysts such as N ‐heterocyclic carbenes (NHCs), acetone cyanohydrin, N ‐iodosuccinimide, trichlorocyanuric acid (TCCA), etc . Furthermore, cyanide‐promoted reactions, along with oxone‐ and iodine‐promoted, reactions are also available in the literature for the conversion of aldehydes into esters.…”

Chemoselective and Metal-Free Synthesis of Aryl Esters from the Corresponding Benzylic Alcohols in Aqueous Medium Using TBHP/TBAI as an Efficient Catalytic System

“…To get rid of a dehydrating agent, different protocols for oxidative esterification of primary alcohols have been reported to produce symmetrical as well as unsymmetrical esters. [1][2][3][4][5][6][7] Some other methods have been developed to generate the ester moiety by the reaction of aryl methyl ketone with I 2 -TBHP, 8 from aryl aldehydes using tert-butyl hydroperoxide (TBHP) in DMSO in the presence of Cu salt to obtain the methyl ester using TBHP as the methyl source 9 and benzyl esters from benzylic alcohols using TBHP in toluene (where toluene delivered the benzyloxy moiety). 10 Recently, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) catalyzed oxidation using Oxone and calcium chloride have been reported to produce esters.…”

“…12 Very recently, the mechanistic pathway of vicinal difunctionalization of alkenes with iodine and TBHP was established 13 where 1-(tert-butylperoxy)-2-iodoethanes were obtained as the products. However, many of the reported methods suffer from the drawbacks like moisture sensitivity of the sophisticated reagent systems, [3][4][5][6][7][8] relatively long reaction time, [2][3][4][5][6][8][9][10][11][12][13] involvement of exotic reagents containing expensive metals, [1][2][3][4]9,11 lack of chemoselectivity, [1][2][3][4]6,11 formation of byproducts, and limited applicability to selected domain of substrates. 2,3,6,[9][10][11] Therefore, development of a highly chemoselective metal-free oxidative protocol for esterification from the primary alcohol is in great demand in the present scenario.…”