333-60-8

Electron-donating group-substituted 2-iodoxybenzoic acids (IBXs) such as5-Me-IBX (1g), 5-MeO-IBX (1h), and 4,5-Me2-IBX were superior to IBX 1a as catalysts for the oxidation of alcohols with Oxone (a trad emark of DuPont) under nonaqueous conditions, although Oxone was almost insoluble in most organic solvents. The catalytic oxidation proceeded more rapidly and cleanly in nitromethane. Furthermore, 2-iodoxybenzenesulfonic acid (IBS, 6a) was much more active than modified IBXs. Thus, we established a highly efficient and selective method for the oxidation of primary and secondary alcohols to carbonyl compounds such as aldehydes, carboxylic acids, and ketones with Oxone in nonaqueous nitromethane, acetonitrile, or ethyl acetate in the presence of 0.05-5molpercentof 6a, which was generated in situ from 2-iodobenzenesulfonic acid (7a) or its sodium salt. Cycloalkanones could be further oxidized to α,β- cycloalkenones or lactones by controlling the amounts of Oxone under the same conditions as above. When Oxone was used under nonaqueous conditions, Oxone wastes could be removed by simple filtration. Based on theoretical calculations, we considered that the relatively ionic character of the intramolecular hypervalent iodine-OSO2 bond of IBS might lower the twisting barrier of the alkoxyperiodinane intermediate 16.

Radical-mediated single carbonylation of alkyl iodides furnishing carboxylic acids proceeded in water using phosphinic acid as a radical initiator in the presence of a surfactant (CTAB). On the other hand, formation of double carbonylation product (α-keto carboxylic acid) along with single carbonylation product was observed for the first time, when the reaction was carried out in aqueous ethanol without any surfactants.

The enzymatic oxidation of a variety of saturated and unsaturated aliphatic derivatives of racemic 2-hydroxy acids 1 to their 2-oxo acids 2 with molecular oxygen catalyzed by the glycolate oxidase from spinach (Spinacia oleracea) was shown to proceed highly enantioselectively.Thus, the glycolate oxidase-catalyzed kinetic resolution provides a convenient biocatalytic method for the preparation of enantiomerically pure (R)-2-hydroxy acids.The absolute configuration of the (R)-2-hydroxy acid 1b assigned by comparison of the measured optical rotation value with that of the literature data and by application of the exciton-coupled circular dichroism method (ECCD) on its bichromophoric 2-naphthoate 9-methylanthryl derivative 3b.These results establish the ECCD method as a convenient microscale chirooptic tool for the configurational assignment of 2-hydroxy acids.

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m-Chloroperoxybenzoic or peroxyformic acid oxidation of 3,4-disubstituted isoxazolin-5-ones affords the corresponding 4-hydroxy derivatives from which, by ring opening, nitriles and α-keto acids are obtained.

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