- Preparation and Palladium-Catalyzed Cross-Coupling of Aryl Triethylammonium Bis(catechol) Silicates with Aryl Triflates
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Pentavalent aryl and heteroaryl bis(catechol) silicates undergo palladium-catalyzed cross-coupling with aryl and heteroaryl triflates in the presence of a fluoride source in excellent yields. These solid, air-stable bis(catechol) silicates are prepared from a high-yielding displacement reaction between catechol and an aryl siloxane in the presence of an amine base. The cross-coupling reaction is tolerant of a wide range of electron-donating and electron-withdrawing groups. Several examples of di-ortho-substituted triflates are successfully coupled with these reagents.
- Seganish, W. Michael,DeShong, Philip
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p. 1137 - 1143
(2007/10/03)
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- Potassium organotrifluoroborates: New partners in palladium-catalysed cross-coupling reactions
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The preparation of various potassium organotrifluoroborates bearing either aryl, alkenyl, or alkynyl substituents is described. These stable salts are shown to be very efficient partners in palladium-catalysed cross- coupling reactions with arenediazonium salts, affording biaryl and styrene derivatives in high yields.
- Darses, Sylvain,Michaud, Guillaume,Genet, Jean-Pierre
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p. 1875 - 1883
(2007/10/03)
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- Oxidation Reduction Reactions Involving Nitro Groups in Trifluoromethanesulfonic Acid. Part 2. The Reactions of Chloromethylbenzenes with Aromatic Nitro Compounds
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2-Chloro-1,3-dimethylbenzene reacts with 1,4-dinitrobenzene in trifluoromethanesulfonic acid (99percent) at 70 deg C to give, after quenching, a 45percent yield of tris(4-chloro-3,5-dimethylphenyl)methanol.Some other chloro compounds and a range of aromat
- Austin, Rupert P.,Ridd, John H.
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p. 1205 - 1210
(2007/10/02)
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- Oxidation-Reduction Reactions Involving Nitro Groups in Trifluoromethanesulfonic Acid. Part 3. The Reactions of 2-Nitrobenzyl Alcohol and Related Compounds
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2-Nitrobenzyl alcohol reacts with trifluoromethanesulfonic acid (99percent) at 90 deg C to give a 66percent yield of 4-amino-3-carboxyphenyl trifluoromethanesulfonate 4.The reaction occurs through the intermediate formation of the C-protonated conjugate acid of anthranil N-oxide 7 and then probably involves the mono- and di-protonated forms of 2-nitrosobenzaldehyde.Under the same conditions, 2-nitrobenzyl chloride and 2-nitrosobenzaldehyde react to give the same product in essentially the same yield.Low temperature reactions in trifluoromethanesulfonic acid permit the conversion of N-phenylhydroxylamine into 4-aminophenyl trifluoromethanesulfonate in a yield of 78percent.
- Austin, Rupert P.,Ridd, John H.
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p. 1411 - 1414
(2007/10/02)
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- N- and C-Attacks of Phenylnitrenium Ions Generated from Phenyl Azides in the Presence of Trifluoroacetic Acid and/or Trifluoromethanesulphonic Acid
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Phenylnitrenium ions were generated from phenyl azides in the presence of trifluoroacetic acid (TFA) and/or trifluoromethanesulphonic acid (TFSA).Unsubstituted phenylnitrenium ions and those with an electron-withdrawing group such as NO2 or CN undergo aromatic N-substitution, whereas those with an electron-donating group such as Me, OMe, CH2Ph, or Ph undergo C-substitution, hydrogen abstraction, and tar formation.The special character of TFA and TFSA as compared with other acids is discussed.
- Takeuchi, Hiroshi,Takano, Katsuyuki
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p. 611 - 618
(2007/10/02)
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