Hydrogen peroxide oxidation catalyzed by heteropoly acids combined with cetylpyridinium chloride. Epoxidation of olefins and allylic alcohols, ketonization of alcohols and diols, and oxidative cleavage of 1,2-diols and olefins
Highly efficient catalytic oxidation of alcohols with molecular oxygen by N-hydroxyphthalimide (NHPI) combined with a Co species was developed. The oxidation of 2-octanol in the presence of catalytic amounts of NHPI and Co(OAc)2 under atmospheric dioxygen in AcOEt at 70 degrees C gave 2-octanone in 93% yield. The oxidation was significantly enhanced by adding a small amount of benzoic acid to proceed
Direct Catalytic Transformation of Olefins into α-Hydroxy Ketones with Hydrogen Peroxide Catalyzed by Peroxotungstophosphate
作者:Yasuyuki Sakata、Yuji Katayama、Yasutaka Ishii
DOI:10.1246/cl.1992.671
日期:1992.4
Aliphatic olefins were directly converted into α-hydroxy ketones with acidic aqueous hydrogenperoxide in the presence of catalytic amount of peroxotungstophosphate (PCWP) under the biphasic system using chloroform as a solvent. The acidic medium was necessary to open the resulting epoxide to vic-diol which was subsequently oxidized to α-hydroxy ketones.
The reaction of 1,2-diols with dimethyl sulfoxide-catalytic molybdenum peroxide in refluxing toluene generally resulted in monoprotection of diols to give 2-methylthiomethoxy-l-ols (Course A) Exceptionally, a) cis-1,2-cyclooctanediol and benzopinacol, and b) 1,2-cyclododecanediol caused C–C bond cleavage (Course B) and monooxidation (Course C), respectively as Scheme 1.
Olefins were smoothly epoxidized under O2 (1 atm) in the presence of a hydrocarbon such as ethylbenzene or tetralin, using N-hydroxyphthalimide (NHPI) and Mo(CO)6 as catalyst; the present reaction involves autoxidation of the hydrocarbon assisted by NHPI and epoxidation of alkenes with the resulting hydroperoxide catalyzed by Mo(CO)6; cis-alkene was epoxidized in a stereospecific manner to form the
A facile conversion of olefins into carboxylic acids could be achieved by using aqueous hydrogen peroxide (35%-H2O2) in the presence of catalytic amounts of tungstic acid (5 wt%). The oxidation was markedly influenced by the acidity of the reaction medium, and it was found to proceed favorably under a weak acidic condition (pH 4–5).