Search results for "oxirane"
showing 10 items of 20 documents
CCDC 1498219: 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
CCDC 1498220: 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
CCDC 2024395: Experimental Crystal Structure Determination
2021
Related Article: Florian Kleemiss, Erna K. Wieduwilt, Emanuel Hupf, Ming W. Shi, Scott G. Stewart, Dylan Jayatilaka, Michael J. Turner, Kunihisa Sugimoto, Eiji Nishibori, Tanja Schirmeister, Thomas C. Schmidt, Bernd Engels, Simon Grabowsky|2021|Chem.-Eur.J.|27|3407|doi:10.1002/chem.202003978
Influence of Remote Substituents on the Equatorial/Axial Selectivity in the Monooxygenation of Methylene C−H Bonds of Substituted Cyclohexanes
2001
The reactivity of individual C--H bonds in the methyl(trifluoromethyl)dioxirane TFDO oxygenation of stereogenic methylene groups in conformationally homogeneous monosubstituted cyclohexanes (2) has been determined. The unexpectedly high occurrence of O-atom insertion into C--H(ax) bonds suggests an in plane trajectory attack in the oxygenation while the diastereoselectivity of the reaction is qualitatively interpreted on the basis of the distinct hyperconjugative stabilization by the substituent of diastereomeric transition states due to long-range through bond interactions.
Oxyfunctionalization of Aliphatic Esters by Methyl(trifluoromethyl)dioxirane
1996
The oxidation of lineal, cyclic, and bicyclic aliphatic p-chlorobenzoic and p-chorobenzenesulfonic acid esters 2 with methyl(trifluoromethyl)dioxirane (TFDO) (1) occurs at positions in the hydrocarbon chain distant from the directing group with a significant degree of selectivity to give the corresponding keto or hydroxy esters. Compounds 2 are relatively deactivated with respect to this oxidation due to the electron-withdrawing nature of the ester moiety. Methylene Cα−H and Cβ−H bonds remain unchanged in all cases, but tertiary Cβ−H bonds undergo oxidation with TFDO (1). Stereoelectronic factors are used to explain the faster reaction rate in competition experiments for the oxidation of en…
Mechanism of the Oxidation of Sulfides by Dioxiranes. 1. Intermediacy of a 10-S-4 Hypervalent Sulfur Adduct
2002
Earlier studies established that dimethyldioxirane (1a) reacts with sulfides 2 in two consecutive concerted electrophilic oxygen-transfer steps to give first sulfoxides 3 and then sulfones 4. The same sequential electrophilic oxidation model was assumed for the reaction of sulfides 2 with the strongly electrophilic methyl(trifluoromethyl)dioxirane (1b). In this paper we report on a systematic and general study on the mechanism of the reaction of simple sulfides 2 with DMDO (1a) and TFDO (1b) which provides clear evidence for the involvement of hypervalent sulfur species in the oxidation process. In the oxidation of sulfides 2a-c, diphenyl sulfide (2d), para-substituted aryl methyl sulfides …
Iodomethane Oxidation by Dimethyldioxirane: A New Route to Hypoiodous Acid and Iodohydrines
1999
The oxidation of iodomethane with dimethyldioxirane allows the generation of stable neutral solutions of hypoiodous acid in the absence of any trapping agent for iodide anion. Hypoiodous acid is trapped in situ by addition to representative olefins to give iodohydrines in good yields. The stereochemical study of the products shows the anti-stereospecific nature of the iodohydroxylation reaction.
Mechanism of the oxidation of sulfides by dioxiranes: conformational mobility and transannular interaction in the oxidation of thianthrene 5-oxide.
2004
The detailed study of the oxidation of thianthrene 5-oxide (1) with methyl(trifluoromethyl)dioxirane (5b) in different solvents and in the presence of (18)O isotopic tracers is reported. Thianthrene 5-oxide (1) is a flexible molecule in solution, and this property allows for transannular interaction of the sulfoxide group with the expected zwitterionic 7 and hypervalent 10-S-4 sulfurane 9 intermediates formed in the oxidation and biases the course of the reaction toward the monooxygenation pathway.
On the Reactivity of C(sp3)–H σ-Bonds: Oxygenation with Methyl(trifluoromethyl)dioxirane
2008
The reactivity of C–H σ-bonds of a series of 2-substituted adamantanes 2 towards methyl(trifluoromethyl)dioxirane (1) shows a consistent dependence on the electron-withdrawing ability, either inductive or by resonance, of the substituent. The results are interpreted in terms of the ability of the substrate molecule to delocalize the electronic perturbation of the reacting center at the beginning of the reaction path. The model shows that the electronic demand from the reacting C–H σ-bond is transmitted along the substrate through a chain of hyperconjugative interactions, the relative intensities of which depend on the σ-bonds involved. The substrate molecule simultaneously provides positive…
Crystal structure of the diglycidyl ether of eugenol
2017
The diepoxy monomer (DGE-Eu) was synthesized from eugenol by a three-step reaction. It consists of a 1,2,4-trisubstituted benzene ring substituted by diglycidyl ether, a methoxy group and a methyloxirane group. The three-membered oxirane rings are inclined to the benzene ring by 61.0 (3) and 27.9 (3)°. In the crystal, molecules are linked by C—H⋯O hydrogen bonds, forming layers parallel to the ab plane.