- Amberlyst-15: A reusable heterogeneous catalyst for the dehydration of tertiary alcohols
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Tertiary alcohols react under mild conditions in the presence of Amberlyst-15 (dry) (solid-supported sulfonic acid) to give predominantly the most stable alkene in very good yield. The dehydration of tertiary alcohol functionality occurs without observation of rearrangement and polymerization products, and with outstanding substrate tolerance, which include the NHCBz, NHBoc, OSEM, OTBDMS, OBOM and ethylene ketal functional groups. Amberlyst-15 (dry) can be easily recovered from the reaction medium and reused for five cycles, maintaining the catalytic efficiency. In addition, the dehydration can occur under continuous operation.
- Frija, Luís M.T.,Afonso, Carlos A.M.
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p. 7414 - 7421
(2012/09/22)
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- Pd-catalyzed carbonylative cross-coupling reactions by triorganoindiums: Highly efficient transfer of organic groups attached to indium under atmospheric pressure
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(Matrix presented) A highly atom-efficient synthetic method of unsymmetrical ketones was developed by using trialkyl- and triarylindiums, which could be employed as effective cross-coupling partners in Pd-catalyzed carbonylative cross-coupling reactions with a variety of organic electrophiles. The present method produced unsymmetrical ketones and 1,4-diacylbenzenes in good yields with highly efficient transfer of almost all the organic groups attached to the indium under atmospheric pressure of CO gas in THF at 66°C.
- Lee, Phil Ho,Lee, Sung Wook,Lee, Kooyeon
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p. 1103 - 1106
(2007/10/03)
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- Suzuki-Miyaura cross-coupling of lithium n-alkylborates
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The palladium-catalyzed cross-coupling of lithium n-alkylborates, generated in situ via addition of sec-butyl lithium to boronate esters, proceeds in moderate to good yields with a wide variety of electrophiles.
- Zou, Gang,Falck
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p. 5817 - 5819
(2007/10/03)
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- Atom-efficient metal-catalyzed cross-coupling reaction of indium organometallics with organic electrophiles
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The novel metal-catalyzed cross-coupling reaction of indium organometallics with organic electrophiles is described. Triorganoindium compounds (R3In) containing alkyl, vinyl, aryl, and alkynyl groups are efficiently prepared from the correspond
- Perez,Sestelo,Sarandeses
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p. 4155 - 4160
(2007/10/03)
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- The first general method for palladium-catalyzed Negishi cross-coupling of aryl and vinyl chlorides: Use of commercially available Pd(P(t-Bu)3)2 as a catalyst
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With a single protocol, commercially available Pd(P(t-Bu)3)2 can effect the Negishi cross-coupling of a wide range of aryl and vinyl chlorides with aryl- and alkylzinc reagents. The process tolerates nitro groups, and it efficiently generates sterically hindered biaryls. In addition, a high turnover number (>3000) can be achieved.
- Dai,Fu
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p. 2719 - 2724
(2007/10/03)
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- Palladium-catalyzed cross-coupling reactions of triorganoindium compounds with vinyl and aryl triflates or iodides
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(matrix presented) A novel palladium-catalyzed cross-coupling reaction of organoindium compounds with vinyl and aryl triflates or iodides is described. The reaction proceeds for alkyl-, vinyl-, alkynyl-, and arylindium compounds in excellent yields and high chemoselectivity without any excess of the organometallic. Remarkably, indium organometallics transfer efficiently the three organic groups attached to the metal.
- Perez, Ignacio,Sestelo, Jose Perez,Sarandeses, Luis A.
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p. 1267 - 1269
(2008/02/09)
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- Cross coupling of vinyl triflates and alkyl Grignard reagents catalyzed by niekel(0)-complexes
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The scope and limitations of the Nickel(0)-catalyzed cross coupling of vinyl triflates with alkyl Grignard reagents have been studied. The effect of triflate substitution, solvent, and especially ligands have been examined. Ligands which are successful for sp2 and sp Grignard reagents fail for sp3 Grignard reagents.
- Busacca, Carl A.,Eriksson, Magnus C.,Fiaschi, Rita
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p. 3101 - 3104
(2007/10/03)
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- REACTIONS OF VINYLSILANES WITH LEWIS ACID-ACTIVATED IODOSYLBENZENE: STEREOSPECIFIC SYNTHESIS OF VINYLIODONIUM TETRAFLUOROBORATES AND THEIR REACTIONS AS HIGHLY ACTIVATED VINYL HALIDES
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Alkenyl(phenyl)iodonium tetrafluoroborates 3 were synthesized from alkenylsilanes 1 by the reaction with iodosylbenzene and boron trifluoride-diethyl ether or triethyloxonium tetrafluoroborate.The reaction proceeds stereospecifically with retention of configuration of 1.X-ray diffraction analysis of (4-tert-butylcyclohexenyl)phenyliodonium tetrafluoroborate (3b) revealed the highly ionic structure with the distorted T-shape arrangement.Iodonium salts 3 behave like the highly activated species of vinyl iodides due to the high leaving ability of the iodine(III) substituents.Thus, a variety of substituted olefins including α-cyano and α-nitro olefins, vinyl sulfides, vinyl halides and α,β-unsaturated esters, were synthesized from 3 under mild conditions.A ligand coupling mechanism via the formation of 10-I-3 intermediate 27 containing a copper(III) ligand is proposed for the substitutions of 3 with nucleophiles.
- Ochiai, Masahito,Sumi, Kenzo,Takaoka, Yoshikazu,Kunishima, Munetaka,Nagao, Yoshimitsu,et al.
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p. 4095 - 4112
(2007/10/02)
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- VINYLIODONIUM SALTS: THEIR STEREOSPECIFIC SYNTHESIS AND REACTIONS AS THE ACTIVATED VINYL HALIDES
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Vinyliodonium salts 2 were synthesized from vinylsilanes 1 by the reaction with iodosylbenzene and triethyloxonium tetrafluoroborate.The reaction occurs stereospecifically with retention of configuration.Vinyliodonium salts 2 are highly effective as the activated species of vinyl iodides.Thus, a variety of substituted olefins including α-cyano and α-nitro olefins, vinyl sulfides, vinyl halides, and α,β-unsaturated esters, were prepared from 2 under mild reaction conditions.
- Ochiai, Masahito,Sumi, Kenzo,Nagao, Yoshimitsu,Fujita, Eiichi
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p. 2351 - 2354
(2007/10/02)
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