نتایج جستجو برای: fluorination

تعداد نتایج: 1361  

Journal: :Organic letters 2002
Dae Young Kim Eun Joo Park

[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...

Journal: :The Journal of organic chemistry 2010
Jeremy Erb Ethan Alden-Danforth Nathan Kopf Michael T Scerba Thomas Lectka

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...

Journal: :Chemical communications 2016
Antonio Bermejo Gómez Miguel A Cortés González Marvin Lübcke Magnus J Johansson Christer Halldin Kálmán J Szabó Magnus Schou

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.

2009
Feng Li Zhonghua Zhu Xiangdong Yao Gaoqing Lu Mingwen Zhao Yueyuan Xia Ying Chen

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...

Journal: :Chemical communications 2015
Xinxin Wu Chunna Meng Xiaoqian Yuan Xiaotong Jia Xuhong Qian Jinxing Ye

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.

Journal: :Chemical communications 2008
Jungwon Kim Jaesang Lee Wonyong Choi

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.

2012
Wen-Bin Yi Xin Huang Zijuan Zhang Dian-Rong Zhu Chun Cai Wei Zhang

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.

2017
Attila Márió Remete Melinda Nonn Santos Fustero Matti Haukka Ferenc Fülöp Loránd Kiss

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...

Journal: :Chemical communications 2013
Tuan Minh Nguyen Hung A Duong Jean-Alexandre Richard Charles William Johannes Fu Pincheng Danson Kwong Jia Ye Eileen Lau Shuying

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.

2014
Yu-hong Lam K. N. Houk

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.

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