Search results for "oxirane"
showing 10 items of 20 documents
CCDC 1498221: Experimental Crystal Structure Determination
2017
Related Article: Ming W. Shi, Scott G. Stewart, Alexandre N. Sobolev, Birger Dittrich, Tanja Schirmeister, Peter Luger, Malte Hesse, Yu-Sheng Chen, Peter R. Spackman,Mark A. Spackman, Simon Grabowsky|2017|J.Phys.Org.Chem.|30|e3683|doi:10.1002/poc.3683
Design, Synthesis, and Biological Evaluation of Novel Fluorinated Ethanolamines
2011
The preparation of novel fluorinated allylamines and their use as key fragments for the stereoselective synthesis of hydroxyethyl secondary amine (HEA)-type peptidomimetics is described. Our strategy employs chiral sulfinyl imines as synthesis intermediates, by treatment of hemiaminal precursors with two equivalents of vinylmagnesium bromide. The subsequent oxidation of the allylic amines to the corresponding epoxides was achieved by treatment with methyl(trifluoromethyl)dioxirane. Finally, epoxide ring opening with a range of nitrogen nucleophiles provided a library of HEA-derived peptidomimetics with a phenyldifluoromethylene moiety. The biological evaluation of these derivatives revealed…
Reactions at Interfaces: Oxygenation of n-Butyl Ligands Anchored on Silica Surfaces with Methyl(trifluoromethyl)dioxirane
2011
The oxygenation of n-butyl and n-butoxy chains bonded to silica with methyl(trifluoromethyl)dioxirane (1) revealed the ability of the silica matrix to release electron density toward the reacting C(2)-H σ-bond through the Si-C(1) and Si-O(1) σ-bonds connecting the alkyl chain to the surface (silicon β-effect). The silica surface impedes neither the alkyl chain adopting the conformation required for the silicon β-effect nor dioxirane 1 approaching the reactive C(2) methylene group. Reaction regioselectivity is insensitive to changes in the solvation of the reacting system, the location of organic ligands on the silica surface, and the H-bonding character of the silica surface. Reaction rates…
A Stereocontrolled Protocol to Highly Functionalized Fluorinated Scaffolds through a Fluoride Opening of Oxiranes
2016
A novel selective and substrate-dependent synthetic protocol has been developed towards the synthesis of various fluorine-containing, highly functionalized cycloalkane derivatives. The method involves the stereoselective epoxidation of some unsaturated cyclic beta-amino acid derivatives as model compounds, followed by a regioselective fluoride opening of oxiranes under various conditions with Deoxofluor and XtalFluor-E reagents, thereby offering an insight into this new epoxide opening methodology with fluoride.
The equilibrium structure and fundamental vibrational frequencies of dioxirane
1998
Complete sets of quadratic and cubic force constants calculated for four isotopomers of dioxirane (CH2OO) are used to estimate vibration-rotation interaction contributions to observed values of rotational constants (B″), thereby yielding empirical estimates of the corresponding equilibrium values (Be). At the highest levels of theory, least-squares refinements of atomic coordinates to both the empirical Be values and the associated isotope shifts yield consistent sets of structural parameters. Recommended values are re(CO)=1.3846±0.0005 A; re(OO)=1.5133±0.0005 A; re(CH)=1.0853±0.0015 A and θe(HCH)=117.03±0.20°. Semidiagonal quartic force constants (in the normal coordinate representation) a…
The oxidation of alkanes with dimethyldioxirane; a new mechanistic insight
1997
Abstract Primary kinetic isotope effects were measured for the oxidation of cyclohexane and methylcyclohexane with DMDO in solution and in the gas phase. These experiments suggest an electrophilic oxygen insertion mechanism for the oxidation of alkanes by DMDO.
Oxygenation of Alkane C−H Bonds with Methyl(trifluoromethyl)dioxirane: Effect of the Substituents and the Solvent on the Reaction Rate
2005
[Chemical reaction: See text] The mechanism of the oxygenation of alkane C-H bonds with methyl(trifluoromethyl)dioxirane (1a) is studied through the effect of the substituent and solvent on the rate of oxygenation of 2-substituted adamantanes (2). The results suggest a remarkable electron deficiency at the reacting carbon atom in the transition state leading to the regular oxygenation products. The linearity of the Hammett plot reveals that the reaction mechanism does not change within a range of 0.15-0.67 units of sigma(I). A change in the solvent does not affect the distribution of the products, indicating a through-bond transmission of the substituent effect as the origin of the deactiva…
CCDC 1543288: Experimental Crystal Structure Determination
2017
Related Article: J. Vigier, C. François, S. Pourchet, G. Boni, L. Plasseraud, V. Placet, S. Fontaine, H. Cattey|2017|Acta Crystallogr.,Sect.E:Cryst.Commun.|73|694|doi:10.1107/S2056989017005370
CCDC 977799: Experimental Crystal Structure Determination
2015
Related Article: Ming W. Shi, Alexandre N. Sobolev, Tanja Schirmeister, Bernd Engels, Thomas C. Schmidt, Peter Luger, Stefan Mebs, Birger Dittrich, Yu-Sheng Chen, Joanna M. Bąk, Dylan Jayatilaka, Charles S. Bond, Michael J. Turner, Scott G. Stewart, Mark A. Spackman and Simon Grabowsky|2015|New J.Chem.|39|1628|doi:10.1039/C4NJ01503G
CCDC 892598: Experimental Crystal Structure Determination
2013
Related Article: C.Lohoelter, D.Schollmeyer, S.R.Waldvogel|2012|Eur.J.Org.Chem.|2012|6364|doi:10.1002/ejoc.201200970