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61.
62.
Ion Ghiviriga Miles A. Rubinski William R. Dolbier Jr 《Magnetic resonance in chemistry : MRC》2016,54(7):592-596
Through‐space 19F–15N couplings revealed the configuration of flubenzimine, with the CF3 group on N4 pointing towards the lone pair of N5. The 19F–15N coupling constants were measured at natural abundance using a spin‐state selective indirect‐detection pulse sequence. As 15N‐labelled proteins are routinely synthesized for NMR studies, through‐space 19F–15N couplings have the potential to probe the stereochemistry of these proteins by 19F labelling of some amino acids or can reveal the site of docking of fluorine‐containing drugs. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
63.
Efficient Cu‐catalyzed Atom Transfer Radical Addition Reactions of Fluoroalkylsulfonyl Chlorides with Electron‐deficient Alkenes Induced by Visible Light
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Dr. Xiao‐Jun Tang Prof. Dr. William R. Dolbier Jr. 《Angewandte Chemie (International ed. in English)》2015,54(14):4246-4249
Fluoroalkylsulfonyl chlorides, RfSO2Cl, in which Rf=CF3, C4F9, CF2H, CH2F, and CH2CF3, are used as a source of fluorinated radicals to add fluoroalkyl groups to electron‐deficient, unsaturated carbonyl compounds. Photochemical conditions, using Cu mediation, are used to produce the respective α‐chloro‐β‐fluoroalkylcarbonyl products in excellent yields through an atom transfer radical addition (ATRA) process. Facile nucleophilic replacement of the α‐chloro substituent is shown to lead to further diverse functionalization of the products. 相似文献
64.
Building on recent results of Umemoto and Winter, an improved method of synthesis of arylsulfur trifluorides, including the excellent, new deoxofluorination reagent Fluolead, is hereby reported. The method utilizes Br2 and KF as oxidizing and fluorinating reagents for efficient, high yield conversion of aryl disulfides and mercaptans to arylsulfur trifluorides. It has also been shown that both Fluolead and mesitylsulfur trifluoride may be generated in acetonitrile and used as in situ deoxofluorination reagents for conversion of either aldehydes or ketones to their respective gem-difluoro compounds. An analysis of the probable mechanism of action, including computational efforts, allows postulation of a rationale for the highly variable reactivities of different arylsulfur trifluorides as deoxofluorination reagents. 相似文献
65.
66.
A mathematical model describing the coupling of electrical,optical and thermal effects in semiconductor lasers is introduced.Numerical and asymptotic solutions are derived, including expressionsfor key physical quantities such as the initial time delay,the frequency of spike oscillation and the temperature rise,together with its influence on the photon density, the electronconcentration and the threshold current. The consequences ofthermal effects in reducing efficiency are thus quantified. 相似文献
67.
The title compounds were synthesized CF2: addition to the respective methylenecyclopropanes. The hexafluorospiropentane thermally rearranges to 2,2,4,4-tetrafluoro-1-(difluoromethylene)cyclobutane in competition with CF2: extrusion, whereas perfluorospiropentane decomposes exclusively by CF2: extrusion. 相似文献
68.
William R. Dolbier Maria Odaniec Ewa Gomulka Mariusz Jaskolski Henryk Koroniak 《Tetrahedron》1984,40(20):3945-3948
The first x-ray structure determination of a fluorine-substituted cyclopropane is reported. The title compound was synthesized via difluorocarbene addition to 1,4-cyc1ohexadiene and its structure determined via x-ray crystallographic techniques. Its cyclopropane bondlengths (1.552 and 1.452) are very similar to those reported earlier in a microwave study of the parent 1,1-difluorocyclopropane, while its cyclohexane ring is virtually planar. 相似文献
69.
The nucleophilic trifluoromethylation reagent derived from CF3I and tetrakis(dimethylamino)ethylene (TDAE) was found to be effective in addition to both N-tosyl aldimines and N-tolyl sulfinimines, the latter reaction exhibiting very good diastereoselectivity. 相似文献
70.
William R. Dolbier Jr. 《Journal of fluorine chemistry》2005,126(2):157-163
In this “perspective” paper, some of the landmark discoveries and accomplishments of the past within the field of fluorine chemistry will be reviewed. Within this review, the dramatic changes (and growth in size and diversity) that the field has undergone, particularly over the last 50 years, will also be discussed. Then finally, where fluorine chemistry is and where it appears to be going will be briefly discussed. The future of fluorine chemistry indeed appears bright, with fluorine chemistry set to play a role, and usually a significant role in most important areas of technology of the 21st century. New perspectives will be required, but then, fluorine chemists have been providing such “new perspectives” to this ever-changing field for the last 75 years. 相似文献