- A novel trifluoromethylation method of saturated organic halides
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Treatment of methyl chlorodifluoroacetate with aliphatic halides in the presence of equivalent ammount of potassium fluoride, copper iodide and cadmium iodide at 120°C in HMPA for 8 h gave the corresponding trifluoromethyl derivatives in moderate yields.
- Chen, Qing-Yun,Duan, Jian-Xing
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- 1-[Hydroxy(sulfonyloxy)iodo]-2,2,2-trifluoroethanes, CF3CH2I(OH)OSO2R: Stable, fluoroalkyl analogs of Koser's reagent
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1-[Hydroxy(sulfonyloxy)iodo]-2,2,2-trifluoroethanes [CF3CH2I(OH)OSO2R; R = CH3, CF3, p-CH3C6H4] can be prepared in two steps from trifluoroethyliodide by oxidation with pertrifluoroacetic acid and subsequent reaction with TsOH, MsOH, or Me3SiOTf. Reaction of the tosylate derivative 3 with silyl enol ethers affords α-tosyloxyketones, while triflate 5 smoothly reacts with trimethylsilylbenzene to give the respective trifluoroethyl(phenyl)iodonium triflate 8.
- Zhdankin, Viktor V.,Kuehl, Chris J.,Simonsen, Angela J.
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p. 2203 - 2206
(2007/10/02)
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- 1-Iodo-polyfluoroalkanes from polyfluoroalkoxy trimethylsilanes and iodochloro triphenylphosphorane
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Polyfluoroalkoxy trimethylsilanes R(f)CH2OSi(CH3)3 (from the alcohols R(f)CH2OH and HMDS), react with Pb3PICI (from ICI and Ph3P) eliminating (CH3)3SiCl. Pyrolysis of the residues gives Ph3PO and pure iodides R(f)CH2I.
- Montanari,Quici,Resnati
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p. 1941 - 1944
(2007/10/02)
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- Unimolecular Rate Constants for Chemically Activated 1,1,1-Trifluoro-2-chloroethane: A Competitive Three-Channel System
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Chemically activated CF3CH2Cl was prepared with 97.5 kcal/mol of internal energy by the combination of CF3 and CH2Cl radicals.The total unimolecular decomposition rate constant was measured by using two internal standard methods and the average was (7.5 +/- 2.61.5) * 106 s-1.The rate constant for four-centered elimination of HF was measured as (2.8 +/- 0.1) * 106 s-1, for C-Cl bond homolysis the rate constant was (0.8 +/- 5.60.1) * 106 s-1, and by difference the three-centered HCl elimination rate constant was (3.9 +/- 2.63.0) * 106 s-1.These rate constants were compared to predictions from RRKM theory, and threshold energies were assigned for loss of HF (76 kcal/mol), for C-Cl-bond rupture (83 kcal/mol), and for HCl elimination (72 kcal/mol).Product distributions from three activation methods (chemical, multiphoton laser, and thermal) were analyzed to develop a self-consistent view of this complex reaction system.
- Rakestraw, David, J.,Holmes, Bert E.
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p. 3968 - 3975
(2007/10/02)
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- Iodinolysis of the Co-C bond in trans-bis(dimethylglyoximato)alkyl(4-cyanopyridine)-cobalt(III) complexes: Evidence for a bimolecular oxidative mechanism
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The iodinolysis of 4CNpyCo(DH)2R (4CNpy = 4-cyanopyridine; R = CH3, CH2CH3, CH2CH2CH3, CH-(CH3)2, CH2C6H5, CH2CF3) in benzene solution is first-order with respect to both the concentration of organocobalt-(III) complex and iodine. The appearance of a transient EPR signal due to an organocobalt(IV) intermediate and the strong correlation of the logarithm of the pseudo-first-order rate constants for iodinolysis with reversible oxidation potentials along with other pertinent observations strongly suggest that the rate-limiting step of the reaction is oxidation of the six-coordinate organocobalt-(III) complex by iodine.
- Toscano, Paul J.,Barren, Elizabeth,Seligson, Allen L.
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p. 2085 - 2088
(2008/10/08)
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