A Diacetate Ketone-Catalyzed Asymmetric Epoxidation of Olefins
نویسندگان
چکیده
منابع مشابه
Design and Synthesis of Binaphthol-Derived Chiral Ketone Catalysts for Dioxirane-Mediated Asymmetric Epoxidation of Olefins
Binaphthol-derived chiral ketones 1a-c were synthesized and were shown to serve as active catalysts for asymmetric epoxidation of olefins using Oxone®, although their enantioselectivities were not high. However, very interestingly, the stereochemical outcome of the resulting epoxides implicates that in the epoxidation using 1ac, the planar transition state may be more favorable than the spiro t...
متن کاملAsymmetric epoxidation of olefins catalyzed by Ti(salan) complexes using aqueous hydrogen peroxide as the oxidant*
Ti(salan) complexes were found to be efficient catalysts for asymmetric epoxidation with aqueous hydrogen peroxide as the oxidant. In the presence of pH 7.4 phosphate buffer, the reaction of various conjugate olefins proceeded smoothly to afford the corresponding epoxides in high yield with high enantioselectivity, even on a multigram scale. Ti(salan) complexes could be prepared from Ti(OiPr)4 ...
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90 A practical method of olefin epoxidation was developed by combining FeCl3·6H2O and 1methylimidazole in acetone using H2O2 as the terminal oxidant. This system showed very good reactivity toward epoxidation of both terminal and substituted alkenes. The use of tridentate and tetradentate amine-bis(phenolate) ligands as additives was also examined. Modest improvement in selectivity was achieved...
متن کاملAn efficient ketone-catalyzed epoxidation using hydrogen peroxide as oxidant.
Epoxides are very important building blocks in organic synthesis.1 Dioxiranes, either isolated or generated in situ, have been shown to be extremely versatile epoxidation reagents.2-6 In nearly every case, the generation of dioxiranes uses potassium peroxomonosulfate (KHSO5) as oxidant (Scheme 1).7,8 During our recent study on asymmetric epoxidation using the fructose-derived ketone (1), we fou...
متن کاملNickel-catalyzed asymmetric transfer hydrogenation of conjugated olefins.
Asymmetric transfer hydrogenation of electron-deficient olefins is realized with nickel catalysts supported by strongly σ-donating bisphosphines. Deuterium labeling experiments point to a reaction sequence of formate decarboxylation, asymmetric hydride insertion and non-stereoselective protonation of resulting nickel enolates.
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ژورنال
عنوان ژورنال: The Journal of Organic Chemistry
سال: 2009
ISSN: 0022-3263,1520-6904
DOI: 10.1021/jo900330n