| Research Abstract |
Reduction-oxygenation of alpha, beta, gamma, delta-unsaturated carbonyl compounds with molecular oxygen (1 atm) and triethylsilane in the presence of a catalytic amount of cobalt (II) porphyrin proceeded rapidly and regioselectively to afford gamma-hydroperoxy-alpha, beta-unsaturated carbonyl compounds in good yields. The obtained hydroperoxides were converted in one pot into gamma-hydroxy-alpha, beta-unsaturated carbonyl compounds by reducing with trimethyl phosphite, and into gamma-oxo-alpha, beta-unsaturated carbonyl compounds by treating with acetic anhydride and 4- (N,N-dimethylamino) pyridine.
Total synthese of some biologically active natural products were attempted by the application this reductive oxygenation. (-) -Pyrenophorin, a 16-membered antibiotic macrolide, was synthesized via the reductive oxygenation of ethyl (2E,4E,7S) -7-acetoxy-2,4-octadienoate prepared from D-glucose. 6-Hydroxyshojail and related furanoids, new antioxidative compounds isolated from Ginger, were also synthesized in good yields from vanillin.
Furthermore, the reductive nitrosation of stirenes and alpha, beta-unsaturated esters with alkyl nitrite and triethylsilane was found to be catalyzed by cobalt (II) porphyrin, to produce acetophenone oximes and alpha-hydroxyimino esters, respectively. Further studies of this nitosation are now in progress in detail.
In this reseach, novel and widespread methods for conversion of conjugated olefins into the correponding hydroperoxides, alcohols, and ketones could be established by cobalt (II) porphyrin-catalyzed regioselective oxygenation with molecular oxygen and triethylsilane followed by the appropriate treatment.
|
