Results 331 to 340 of about 171,419 (381)

A hafnium-based metal-organic framework as an efficient and multifunctional catalyst for facile CO2 fixation and regioselective and enantioretentive epoxide activation.

Journal of the American Chemical Society, 2014
Porous heterogeneous catalysts play a pivotal role in the chemical industry. Herein a new Hf-based metal-organic framework (Hf-NU-1000) incorporating Hf6 clusters is reported.
M. Beyzavi, Rachel C. Klet, Samat Tussupbayev, Joshua D. Borycz, Nicolaas A. Vermeulen, C. Cramer, J. Stoddart, J. Hupp, O. Farha, O. Farha   +9 more
semanticscholar   +1 more source

Mechanistic Insights into Water-Mediated Tandem Catalysis of Metal-Coordination CO2/Epoxide Copolymerization and Organocatalytic Ring-Opening Polymerization: One-Pot, Two Steps, and Three Catalysis Cycles for Triblock Copolymers Synthesis

, 2016
The addition of water as a chain transfer reagent during the copolymerization reaction of epoxides and carbon dioxide has been shown as a promising method for producing CO2-based polycarbonate polyols.
Guang Wu, D. Darensbourg
semanticscholar   +1 more source

General, Highly Selective Synthesis of 1,3- and 1,4-Difunctionalized Building Blocks by Regiodivergent Epoxide Opening.

Angewandte Chemie, 2016
We describe a regiodivergent epoxide opening (REO) featuring a catalyst-controlled synthesis of enantiomerically and diastereomerically highly enriched or pure syn- and anti- 1,3- and 1,4-difunctionalized building blocks from a common epoxide precursor ...
Nico Funken, Felix Mühlhaus, A. Gansäuer   +2 more
semanticscholar   +1 more source

Reactions of epoxides—I

Tetrahedron, 1964
Abstract New preparative routes to the 13α,17aα-epoxide (II) and the 13β,17aβ-epoxide (III) are described. Boron trifluoride in benzene converts the α-epoxide (II) into a mixture from which five products were isolated, but the β-epoxide (III) gives only the 17aβ-hydroxy-Δ8(14)-olefin (VIII).
James M. Coxon, M. P. Hartshorn, D.N. Kirk   +2 more
openaire   +4 more sources

Epoxidation of homoisoflavones

Journal of Heterocyclic Chemistry, 2003
AbstractA comparative study of the epoxidation of homoisoflavones (3‐benzyl‐4‐chromones) 1–4 has been performed by various oxidizing agents, víz. Epoxidation with isolated dimethyldioxirane (Method A), with alkaline hydrogen peroxide (Method B), and with sodium hypochlorite (Method C) to obtain the epoxides 4–8.
openaire   +3 more sources

Ceramide-epoxides

Chemistry and Physics of Lipids, 2001
Previously unknown 4,5-epoxy-N-acetyl-sphingosine (1) was synthesized by epoxidation of N-acetyl-sphingosine with 1,1-dimethyldioxirane. A by-product generated by HPLC purification is the tetrahydrofuryl derivative of acetamide (2). Mainly allylic oxidation was observed when natural ceramides were reacted with dimethyldioxirane.
A, Möllenberg, G, Spiteller
openaire   +2 more sources

Enantioselectivities of yeast epoxide hydrolases for 1,2-epoxides

Tetrahedron: Asymmetry, 1999
Abstract Kinetic resolution of homologous series of unbranched 1,2-epoxyalkanes (C-4 to C-12), 1,2-epoxyalkenes (C-4, C-6 and C-8), a 2,2-dialkylsubstituted epoxide (2-methyl-1,2-epoxyheptane) and a benzyloxy-substituted epoxide (benzyl glycidyl ether) was investigated using resting cells of 10 different yeast strains.
Botes, A.L., Weijers, C.A.G.M., Botes, P.J., van Dyk, M.S.   +3 more
openaire   +3 more sources

Carbon Dioxide/Epoxide Copolymerization via a Nanosized Zinc–Cobalt(III) Double Metal Cyanide Complex: Substituent Effects of Epoxides on Polycarbonate Selectivity, Regioselectivity and Glass Transition Temperatures

, 2015
In this study, we describe the substituent effect of epoxides on CO2/epoxide copolymerization catalyzed by a nanosized zinc–cobalt(III) double metal cyanide complex [Zn–Co(III) DMCC].
Xing-hong Zhang, R. Wei, Ying-Ying Zhang, B. Du, Zhiqiang Fan   +4 more
semanticscholar   +1 more source

Epoxidation of alkenes

ChemInform, 1991
Publisher Summary The method for asymmetric epoxidation of alicyclic alcohols is known as Sharpless. The success of this method initiated much research into other techniques of asymmetric oxidation of alkenes in general and this chapter considers the progress in the area for the last six years.
openaire   +2 more sources

Enantioselective Cascade Biocatalysis via Epoxide Hydrolysis and Alcohol Oxidation: One-Pot Synthesis of (R)-α-Hydroxy Ketones from Meso- or Racemic Epoxides

, 2015
A new type of cascade biocatalysis was developed for one-pot enantioselective conversion of a meso- or racemic epoxide to an α-hydroxy ketone in high ee via an epoxide hydrolase-catalyzed hydrolysis of the epoxide, an alcohol dehydrogenase-catalyzed ...
Jiandong Zhang, Shuke Wu, Jinchuan Wu, Zhi Li   +3 more
semanticscholar   +1 more source