- A scalable Nenitzescu synthesis of 2-methyl-4-(trifluoromethyl)-1H-indole- 5-carbonitrile
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2-Methyl-4-(trifluoromethyl)-1H-indole-5-carbonitrile is a key intermediate in the synthesis of selective androgen receptor modulators discovered in these laboratories. A practical and convergent synthesis of the title compound starting from 4-nitro-3-(tr
- Boros, Eric E.,Kaldor, Istvan,Turnbull, Philip S.
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- Enantioselective Redox-Divergent Chiral Phosphoric Acid Catalyzed Quinone Diels–Alder Reactions
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An efficient enantioselective construction of tetrahydronaphthalene-1,4-diones as well as dihydronaphthalene-1,4-diols by a chiral phosphoric acid catalyzed quinone Diels–Alder reaction with dienecarbamates is reported. The nature of the protecting group on the diene is key to the success of achieving high enantioselectivity. The divergent “redox” selectivity is controlled by using an adequate amount of quinones. Reversible redox switching without erosion of enantioselectivity was possible from individual redox isomers.
- Bernadat, Guillaume,Gelis, Coralie,Masson, Géraldine,Neuville, Luc,Retailleau, Pascal,Varlet, Thomas
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supporting information
p. 8491 - 8496
(2020/04/10)
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- Effects of B2pin2 and PCy3 on copper-catalyzed trifluoromethylation of substituted alkenes and alkynes with the Togni reagent
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The copper-catalyzed oxytrifluoromethylation of phenylacetylenes and C-H trifluoromethylation of quinones were studied. It was found that both reactions are accelerated by B2pin2 and PCy3 additives. The two reactions have different substituent effects. The oxytrifluoromethylation is faster in the presence of electron-donating groups, while the C-H trifluoromethylation is faster with electron-withdrawing substituents. The Hammett plot for oxytrifluoromethylation gave a ρ value of -0.76 indicating electron demand in the rate determining step of the reaction. According to the absolute value of ρ the reaction probably does not proceed through a rate determining formation of a carbocation intermediate. The kinetic isotope effect measurements indicate that in C-H trifluoromethylation of quinones the cleavage of the C-H bond is not the rate determining step of the reaction.
- Janson, P?r G.,Ilchenko, Nadia O.,Diez-Varga, Alberto,Szabó, Kálmán J.
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p. 922 - 931
(2015/03/30)
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- Copper-mediated C-H trifluoromethylation of quinones
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Quinones undergo copper-mediated C-H trifluoromethylation reactions using a hypervalent iodine reagent. The reactions have a broad synthetic scope involving naphtho, alkyl, chloro and methoxy quinones.
- Ilchenko, Nadia O.,Janson, Paer G.,Szabo, Kalman J.
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supporting information
p. 6614 - 6616
(2013/07/26)
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- Copper-catalyzed direct C-H trifluoromethylation of quinones
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An efficient and practical methodology has been developed to introduce the CF3 group onto quinones through Cu(I)-catalyzed direct C-H trifluoromethylation of quinones.
- Wang, Xi,Ye, Yuxuan,Ji, Guojing,Xu, Yan,Zhang, Songnan,Feng, Jiajie,Zhang, Yan,Wang, Jianbo
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supporting information
p. 3730 - 3733
(2013/08/23)
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- Cyclohexylene-Bridged Porphyrin Quinones with Variable Acceptor Strength as Biomimetic Models for Photosynthesis: Evidence for Twist-Boat Conformation
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Rigidly and covalently linked porphyrin quinones are well-suited as biomimetic model compounds for studying the photoinduced electron transfer (PET) reaction occurring in primary processes of photosynthesis. In this context, the synthesis of new porphyrin quinones with a cis- or trans-1,4-disubstituted cyclohexylene bridge linking the electron donor and the electron acceptor is reported. To study the dependence of the PET rate of the difference of the free enthalpy of the PET reaction, four quinones with different structures and therefore redox potentials were used as electron acceptor components. As a whole, two series of each four new cis- and trans-1,4-cyclohexylene-bridged porphyrin quinones with variable acceptor strength were synthesized. The most important synthetic steps comprised the free radical addition of the ester functionalized cyclohexylene bridge to the quinone, reduction of the ester to the alcohol group with lithium borohydride or DIBALH, oxidation of the alcohol to the corresponding aldehyde with PCC or TEMPO (2,2,6,6-tetramethylpiperidine1-oxyl)/NaOCl, and condensation of these aldehydes with pyrrole and 4-methylbenzaldehyde under equilibrium conditions. Analysis of the 1H NMR spectra unambiguously indicated the chair conformation for the cyclohexane ring of all porphyrin precursors and Zrarcs-cyclohexane-bridged porphyrin quinones, whereas the cis-cyclohexane-bridged porphyrin quinones had the cyclohexane ring in the unusual twist-boat conformation. This was additionally confirmed by an X-ray crystal structure of one of the cis-porphyrin quinones and the corresponding trans-porphyrin quinone. NOE experiments gave information about the spatial arrangement of the diastereomeric target compounds in solution.
- Dieks, Henrik,Senge, Mathias O.,Kirste, Burkhard,Kurreck, Harry
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p. 8666 - 8680
(2007/10/03)
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- Clorous Acid Oxidation of Trifluoromethylphenols: Cyclopentenolones by Benzilic Acid Ring Contraction
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The formation of 2-chloro-2-trifluoromethylcyclopentane-1,3-dione (1) in the chlorous acid oxidation of 2- and 3-trifluoromethylphenol is shown to proceed via decarboxylation of 5-chloro-1-hydroxy-4-oxo-5-trifluoromethylcyclopent-2-enecarboxylic acid (4), an isolable compound.
- Blazejewski, Jean-Claude,Dorme, Regine,Wakselman, Claude
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p. 1861 - 1864
(2007/10/02)
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- Synthesis of 2-Trifluoromethyl-1,3-cyclopentanedione and 2-Trifluoromethyl-1,4-benzoquinone via Chlorous Acid Oxidation of 3-Trifluoromethylphenol
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A new synthesis of 2-trifluoromethyl-1,4-benzoquinone and 2-chloro-2-trifluoromethyl-1,3-cyclopentanedione by oxidation of 3-trifluoromethylphenol with sodium chlorite/sulfuric acid (chlorous acid) is described.In addition, the hydrodechlorination of 2-chloro-2-trifluoromethyl-1,3-cyclopentanedione to give 2-trifluoromethyl-1,3-cyclopentanedione by hydroiodic acid (generated in catalytic amounts from iodine and thiophenol) has been achieved.
- Blazejewski, Jean-Claude,Dorme, Regine,Wakselman, Claude
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p. 1120 - 1121
(2007/10/02)
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