Mild Oxidation of Alcohols with o‐Iodoxybenzoic Acid (IBX) in a Water/CH₂Cl₂ Mixture in the Presence of Phase‐Transfer Catalyst

Abstract

A mild oxidation of alcohols to the respective carbonyl compounds with o-iodoxybenzoic acid (IBX) catalyzed by n-Bu 4 NBr in a water/dichloromethane (1:1) mixture is described. The method offers the advantage of a simple, inexpensive catalyst and the diminution of organic solvent employed in the reaction.

Chemistry of Polyvalent Iodine

“…The synthetic usefulness of IBX in general is significantly restricted by its low solubility in most organic solvents, with the exception of DMSO. However, in several recent reports it has been shown that IBX can be used as an effective oxidant in other than DMSO solvents. − More and Finney have found that primary and secondary alcohols can be oxidized into the corresponding aldehydes or ketones in excellent yields (90−100%) by heating a mixture of the alcohol and IBX in common organic solvents . All reaction byproducts can be completely removed by filtration.…”

“…Kuhakarn and co-workers have recently found that IBX can be used for the oxidation of alcohols in a 1:1 water/dichloromethane mixture in the presence of tetrabutylammonium bromide …”

“…However, in several recent reports it has been shown that IBX can be used as an effective oxidant in other than DMSO solvents. [993][994][995][996] More and Finney have found that primary and secondary alcohols can be oxidized into the corresponding aldehydes or ketones in excellent yields (90-100%) by heating a mixture of the alcohol and IBX in common organic solvents. 993 All reaction byproducts can be completely removed by filtration.…”

“…994 Kuhakarn and co-workers have recently found that IBX can be used for the oxidation of alcohols in a 1:1 water/ dichloromethane mixture in the presence of tetrabutylammonium bromide. 996 IBX is especially useful for the oxidation of 1,2-diols. Moorthy and co-workers have investigated the reactions of IBX with various vicinal diols and found that the oxidative cleavage of the C-C bond, as well as the previously known oxidation to R-ketols or R-diketones, can occur in these reactions.…”

Aqueous Mediated Reactions Involving Hypervalent Iodine Reagents

“…in 2006 reported the mild oxidation of alcohols with IBX in a water/CH 2 Cl 2 mixture in the presence of phase transfer catalyst (PTC), tetrabutylammonium bromide (TBAB) in good yields (Scheme 97). [124] …”