نتایج جستجو برای: fluorination
تعداد نتایج: 1361 فیلتر نتایج به سال:
[reaction: see text] The catalytic enantioselective electrophilic fluorination promoted by quaternary ammonium salt from cinchonine as a phase-transfer catalyst is described. Treatment of beta-keto esters with N-fluorobenzenesulfonimide as the fluorine source under mild reaction conditions afforded the corresponding alpha-fluoro beta-keto esters in exellent yields with good to moderate enantiom...
An examination into the derivatization of various natural products using newly developed alpha-fluorination methodology is disclosed. An activated ketene enolate, generated from an acid chloride, is allowed to react with an electrophilic fluorine source (NFSi). Quenching the reaction with a nucleophilic natural product produces biologically relevant alpha-fluorinated carbonyl derivatives of sel...
Nucleophilic 18F-fluorination of bromodifluoromethyl derivatives was performed using [18F]Bu4NF in the presence of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene). This novel procedure provided a diverse set of [18F]trifluoroacetamides in good to excellent radiochemical conversions. A mechanism where DBU acts as organomediator in this transformation is proposed.
Citation: Li, Feng, Zhu, Zhonghua, Yao, Xiangdong, Lu, Gaoqing, Zhao, Mingwen, Xia, Yueyuan and Chen, Ying 2008-03-14, Fluorination-induced magnetism in boron nitride nanotubes from ab initio calculations, Applied physics letters, vol. 92, no. 10, pp. 102515. The following article appeared in Applied physics letters, vol. 92, no. 10, pp. 102515. and may be found at http://dx.doi.org/10.1063/1.2...
We report herein an efficient, general and green method for decarboxylative fluorination of aliphatic carboxylic acids. By using a transition-metal-free, organocatalytic photoredox system, the reaction of various aliphatic carboxylic acids with the Selectfluor reagent afforded the corresponding alkyl fluorides in satisfactory yields under visible light irradiation at room temperature.
Simultaneously surface fluorinated and platinized TiO2 (F-TiO2/Pt) exhibits a novel photocatalytic activity for the anoxic degradation of organic compounds, which is attributed to the unique synergic effect of surface fluorination and platinization on the photo-induced charge transfer process.
A fluorous cinchona alkaloid ester has been developed as a chiral promoter for the asymmetric fluorination of β-ketoesters. It has comparable reactivity and selectivity to the nonfluorous versions of cinchona alkaloids and can be easily recovered from the reaction mixture by simple fluorous solid-phase extraction (F-SPE) and used for the next round of reaction without further purification.
A study exploring the chemical behavior of some dihydroxylated β-amino ester stereo- and regioisomers, derived from unsaturated cyclic β-amino acids is described. The nucleophilic fluorinations involving hydroxy-fluorine exchange of some highly functionalized alicyclic diol derivatives have been carried out in view of selective fluorination, investigating substrate dependence, neighboring group...
Cascade fluorofunctionalisation of 2,3-unsubstituted indoles by means of electrophilic fluorination.
Cascade fluorofunctionalisation of 2,3-unsubstituted indoles featuring the formation of C-C, C-F and C-O bonds via electrophilic fluorination using N-fluorobenzenesulfonimide is described. The use of an O-nucleophile tethered to the nitrogen of indoles enables the synthesis of polycyclic fluorinated indoline derivatives from simple precursors in 40-63% yields.
The origin of selectivity in the α-fluorination of cyclic ketones catalyzed by cinchona alkaloid-derived primary amines is determined with density functional calculations. The chair preference of a seven-membered ring at the fluorine transfer transition state is key in determining the sense and level of enantiofacial selectivity.
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید