- Visible-Light-Promoted Metal-Free Synthesis of (Hetero)Aromatic Nitriles from C(sp3)?H Bonds**
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The metal-free activation of C(sp3)?H bonds to value-added products is of paramount importance in organic synthesis. We report the use of the commercially available organic dye 2,4,6-triphenylpyrylium tetrafluoroborate (TPP) for the conversion of methylarenes to the corresponding aryl nitriles via a photocatalytic process. Applying this methodology, a variety of cyanobenzenes have been synthesized in good to excellent yield under metal- and cyanide-free conditions. We demonstrate the scope of the method with over 50 examples including late-stage functionalization of drug molecules (celecoxib) and complex structures such as l-menthol, amino acids, and cholesterol derivatives. Furthermore, the presented synthetic protocol is applicable for gram-scale reactions. In addition to methylarenes, selected examples for the cyanation of aldehydes, alcohols and oximes are demonstrated as well. Detailed mechanistic investigations have been carried out using time-resolved luminescence quenching studies, control experiments, and NMR spectroscopy as well as kinetic studies, all supporting the proposed catalytic cycle.
- Murugesan, Kathiravan,Donabauer, Karsten,K?nig, Burkhard
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supporting information
p. 2439 - 2445
(2020/12/07)
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- Preparation of (Pentafluorosulfanyl)benzenes by Direct Fluorination of Diaryldisulfides: Synthetic Approach and Mechanistic Aspects
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Direct fluorination of ortho-, meta- and para-substituted aromatic thiols and disulfides using elemental fluorine afforded substituted (pentafluorosulfanyl)benzenes. This work thus represents the first study of the scope and limitation of direct fluorination for the synthesis of new SF5-containing building blocks. Fluorinations in batch and flow modes were compared. A comprehensive computational study was carried out employing density functional and wave function methods to elucidate the reaction mechanism of the transformation of ArSF3 into ArSF5. Eliminating various nonradical pathways, it has been shown that the reaction proceeds by a radical mechanism, initiated by the attack of the F. on the ArSF3 moiety, propagated via an almost barrierless F2+ArSF4 .→ArSF5+F. step and terminated by the ArSF4 .+F.→ArSF5. Most of the calculated data are in very good agreement with experimental observations concerning the ortho-substituent effect on the reaction rates and yields.
- Ajenjo, Javier,Klepetá?ová, Blanka,Greenhall, Martin,Bím, Daniel,Culka, Martin,Rulí?ek, Lubomír,Beier, Petr
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supporting information
p. 11375 - 11382
(2019/08/20)
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- PENTAFLUOROSULFANYL PHTHALOCYANINE DERIVATIVES AND INTERMEDIATES THEREOF
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Provided is a phthalocyanine derivative of the following general formula (1) which has superior solubility in organic solvents: General formula (1): (wherein M is a hydrogen atom, a metal element, a metalloid element, a metal oxide, a metalloid oxide, a m
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Paragraph 0081-0082
(2015/12/07)
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- 4-(Pentafluorosulfanyl)benzenediazonium Tetrafluoroborate: A Versatile Launch Pad for the Synthesis of Aromatic SF5 Compounds via Cross Coupling, Azo Coupling, Homocoupling, Dediazoniation, and Click Chemistry
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The reagent 4-(pentafluorosulfanyl)benzenediazonium tetrafluoroborate (1) was synthesized and isolated as a stable salt for the first time; its application in a wide assortment of transformations was subsequently investigated. A series of novel SF5-bearing alkenes, alkynes, and biaryl derivatives were synthesized by employing Heck-Matsuda, Sonogashira, and Suzuki coupling protocols. Dediazoniation with TMSX (X = Hal; N3; and CN) and NH4SCN in [BMIM][BF4] as solvent furnished the corresponding p-SF5-C6H4X derivatives. The azide derivative p-SF5-C6H4N3 entered into click chemistry with phenylacetylenes to furnish the corresponding triazoles. The 4,4′-bis(pentafluorosulfanyl)biphenyl was synthesized by homo-coupling using Pd(OAc)2. The corresponding azo compounds were obtained through azo-coupling with reactive aromatic nucleophiles (1,3-dimethoxybenzene, 1,3,5-trimethoxybenzene, 1,2,4-trimethoxybenzene, aniline and phenol). Fluorodediazoniation in [BMIM][PF6] and [BMIM][BF 4] selectively furnished the fluoro derivative p-SF 5-C6H4F. Dediazoniation in [BMIM][NTf 2] gave p-SF5-C6H4OS(O)(CF 3)=NSO2CF3 as the major and p-SF 5-C6H4-NTf2 as the minor products. Homolytic dediazoniation in MeCN/NaI gave the unsymmetrical biaryls p-SF 5-C6H4-Ar (ArH = mesitylene and p-xylene) along with p-SF5-C6H4I. Analysis of the dediazoniation product mixtures indicated that dediazoniation of p-SF 5-C6H4N2+ BF 4- in low nucleophilicity, highly ionizing, solvents (TfOH, TFE, HFIP, TFAH) is mainly heterolytic, while in MeOH it is mainly homolytic. The isodesmic reaction p-SF5-C6H 4+ + R-C6H5 → SF 5-C6H5 + p-R-C6H4 + (with R = NO2, CF3, H) was gauged by DFT at various levels and by PCM. Copyright
- Okazaki, Takao,Laali, Kenneth K.,Bunge, Scott D.,Adas, Sonya K.
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p. 1630 - 1644
(2014/03/21)
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- Synthesis of some arylsulfur pentafluoride pesticides and their relative activities compared to the trifluoromethyl analogues
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Examples of pesticides containing an arylsulfur pentafluoride group were made and their biological activities compared to the corresponding trifluoromethyl analogues. A phenylsulfur pentafluoride analogue of the insecticide fipronil, screened against a resistant strain of Musca domestica, showed higher activity than the corresponding trifluoromethyl analogue.
- Crowley, Patrick J.,Mitchell, Glynn,Salmon, Roger,Worthington, Paul A.
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p. 138 - 142
(2007/10/03)
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