A Convenient Synthesis of 5,6β-Epoxides of Some Cholesteryl Esters and Δ<sup>5</sup>-Ketosteroid Derivatives by Catalytic β-Stereoselective Epoxidation
作者:Jean-Claude Marchon、René Ramasseul
DOI:10.1055/s-1989-27261
日期:——
The epoxidation of a series of cholesteryl esters by air in the presence of a catalytic amount of a ruthenium tetramesitylporphyrin complex is described. The preparative procedure, which requires only 4 to 5 mol % of the catalyst, leads to high conversion (76 to 94 %) and very high β-stereoselectivity (> 99 %). Similar results are obtained in the epoxidation of 3β-acetoxyandrost-5-ene-17-one, 3β-acetoxypregn-5-ene-20-one, and 3,3-ethylenedioxycholest-5-ene.
β-Selective Epoxidation of Cholesterol Derivatives with Molecular Oxygen and Aldehyde Catalyzed by Manganese(II) Complex
作者:Tohru Yamada、Kiyomi Imagawa、Teruaki Mukaiyama
DOI:10.1246/cl.1992.2109
日期:1992.11
In the presence of a catalytic amount of bis(dipivaloylmethanato)manganese(II) (= Mn(dpm)2), various cholesterol derivatives are smoothly converted into the corresponding β-epoxides in good to high yields with combined use of molecular oxygen and isobutyraldehyde. These stereoselectivities are the reversal of the cases using peracid such as mCPBA.
Molybdenum Catalyzed β-Selective Epoxidation of Cholesterol Esters with Molecular Oxygen<sup>+</sup>
作者:M. Lakshmi Kantam、P. Lakshmi Santhi
DOI:10.1080/00397919408020771
日期:1994.4
Molybdenyl(VI) acetylacetonate catalyses the conversion of various cholesterol esters into the corresponding beta-epoxides in good yields with the combined use of molecular oxygen and i-butyraldehyde at room temperature.
MARCHON, JEAN-CLAUDE;RAMASSEUL, RENE, SYNTHESIS,(1989) N, C. 389-391
作者:MARCHON, JEAN-CLAUDE、RAMASSEUL, RENE
DOI:——
日期:——
Nitrous Oxide Oxidation Catalyzed by Ruthenium Porphyrin Complex
Dinitrogen oxide was employed as a clean oxidant for various oxidations in the presence of a catalytic amount of dioxoruthenium tetramesitylporphyrin complex (Ru(tmo)(O) 2 ). A variety of olefins, secondary alcohols, and benzyl alcohols were smoothly oxidized to the corresponding epoxides, ketones, and aldehydes in high yields. In the oxidation of 9,10-dihydroanthracene derivatives, the competitive