- Vapor-phase alkylation of phenol with tert-butyl alcohol catalyzed by H3PO4/MCM-41
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The catalytic performance of Al-MCM-41 containing 5-35 wt H 3PO4 was studied for the vapor-phase alkylation of phenol with tert-butyl alcohol (TBA) from 383 to 493 K. 4-Tert-butyl phenol was produced as the main product with moderate selectivity. The product distribution depends on the reaction temperature, number of acid sites, and the Broensted to Lewis sites ratios. A lower molar ratio of reactants (TBA/phenol = 2) and a higher space velocity facilitated the production of 4-tert-butyl phenol. The influence of various parameters such as temperature, reactant feed molar ratio, feed rate, and time on stream were investigated for conversion yield and product selectivity.
- Ghiaci, Mehran,Aghabarari, Behzad
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Read Online
- Alkylation of Phenol with tert-Butanol in a Draining-Film Reactor
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The alkylation of phenol with tert-butanol in a displacement draining-film reactor on a heterogeneous catalyst, Beta zeolite, was evaluated. Optimum process conditions ensuring the maximal p-tert-butylphenol yield were determined: phenol:tert-butanol molar ratio (3–3.5):1, superficial liquid velocity 1.0–1.5 m3 m–2 h–1, and temperature 100°C–110°C. A procedure ensuring 100% conversion of tert-butanol and isobutylene (a by-product formed from tert-butanol) was observed.
- Maksimov, A. L.,Mel’chakov, I. S.,Terekhov, A. V.,Zanaveskin, L. N.
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p. 569 - 575
(2021/07/26)
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- Sodium Butylated Hydroxytoluene (NaBHT) as a New and Efficient Hydride Source for Pd-Catalysed Reduction Reactions
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NaBHT (sodium butylated hydroxytoluene), a hindered and soluble base for the efficient arylation of various base-sensitive amines and (hetero)aryl halides has been found to have an unanticipated role as a hydride donor to reduce (hetero)aryl halides and allylic acetates. Mechanistic studies have uncovered that NaBHT, but not BHT, can deliver multiple hydrides through oxidation of the benzylic methyl group in NaBHT to the aldehyde. Further, performing the reduction with NaBHT-d20 has revealed that the redox-active benzylic position is not the only hydride donor site from NaBHT with one hydride in three coming, presumably, from the tert-butyl groups. The reduction works well under mild conditions and, incredibly, only consumes 20 percent of the NaBHT in the process; the remaining 80 percent can be readily recovered in pure form and reused. This, combined with the low cost of the material in ton-scale quantity, makes it practical and attractive for wider use in industry at scale.
- Sharif, Sepideh,Rodriguez, Michael J.,Lu, Yu,Kopach, Michael E.,Mitchell, David,Hunter, Howard N.,Organ, Michael G.
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supporting information
p. 13099 - 13103
(2019/10/28)
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- Singlet vs Triplet Reactivity of Photogenerated α,n-Didehydrotoluenes
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The reactivity of α,n-didehydrotoluenes (DHTs) in protic media (organic/aqueous mixtures) was explored by means of a combined computational and experimental approach. These intermediates were generated via a photoinduced double elimination process occurring in (chlorobenzyl)trimethylsilanes and led to the formation of a varied products distribution, depending on the isomer tested. Irradiation of ortho- and para-derivatives resulted, respectively, in the formation of triplet α,2- and α,4-DHTs, whose diradical reactivity led to both radical and polar products. On the other hand, irradiation of the meta-precursor led to the singlet α,3-DHT isomer. The latter showed a marked preference for the formation of polar products and this was rationalized, as supported by computational evidence, via the involvement of a zwitterionic species arising through interaction of the nucleophilic solvent with the benzylic position of the DHT.
- Pedroli, Chiara,Ravelli, Davide,Protti, Stefano,Albini, Angelo,Fagnoni, Maurizio
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supporting information
p. 6592 - 6603
(2017/07/15)
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- A study of diketopiperazines as electron-donor initiators in transition metal-free haloarene-arene coupling
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Several diketopiperazines have been shown to promote carbon-carbon coupling between benzene and aryl halides in the presence of potassium tert-butoxide and without the assistance of a transition metal catalyst. The structure of the diketopiperazine has an influence on its reductive potential and can help to promote the coupling of the more challenging aryl bromides with benzene.
- Cumine, Florimond,Zhou, Shengze,Tuttle, Tell,Murphy, John A.
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p. 3324 - 3336
(2017/04/21)
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- Cleavage of the lignin β-O-4 ether bond: Via a dehydroxylation-hydrogenation strategy over a NiMo sulfide catalyst
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The efficient cleavage of lignin β-O-4 ether bonds to produce aromatics is a challenging and attractive topic. Recently a growing number of studies have revealed that the initial oxidation of CαHOH to CαO can decrease the β-O-4 bond dissociation energy (BDE) from 274.0 kJ mol-1 to 227.8 kJ mol-1, and thus the β-O-4 bond is more readily cleaved in the subsequent transfer hydrogenation, or acidolysis. Here we show that the first reaction step, except in the above-mentioned pre-oxidation methods, can be a Cα-OH bond dehydroxylation to form a radical intermediate on the acid-redox site of a NiMo sulfide catalyst. The formation of a Cα radical greatly decreases the Cβ-OPh BDE from 274.0 kJ mol-1 to 66.9 kJ mol-1 thereby facilitating its cleavage to styrene, phenols and ethers with H2 and an alcohol solvent. This is supported by control experiments using several reaction intermediates as reactants, analysis of product generation and by radical trap with TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) as well as by density functional theory (DFT) calculations. The dehydroxylation-hydrogenation reaction is conducted under non-oxidative conditions, which are beneficial for stabilizing phenol products.
- Zhang, Chaofeng,Lu, Jianmin,Zhang, Xiaochen,Macarthur, Katherine,Heggen, Marc,Li, Hongji,Wang, Feng
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p. 6545 - 6555
(2018/06/06)
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- Air-stable palladium(0) phosphine sulfide catalysts for Ullmann-type C-N and C-O coupling reactions
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This paper describes an efficient procedure for palladium(0)-catalyzed N-arylation and O-arylation of aryl halides by Ullmann-type cross coupling reaction under mild reaction conditions in a short reaction time. Two phosphine sulphide ligands and their corresponding Pd(0) complexes namely [Pd(p2S2)(dba)] and [Pd(pp3S4)(dba)], were synthesized, where p2S2 is 1,2-bis(diphenylphosphino)ethane disulfide, pp3S4 is tris[2-(diphenylphosphino)ethyl]phosphine tetrasulfide and dba is dibenzylideneacetone. Optimal reaction conditions were determined for the arylation reactions using iodobenzene and benzimidazole by varying temperature, solvent, base and catalyst loading. The cross coupling reactions were carried out taking iodobenzenes/bromobenzenes and a wide variety of substituted aryl amines/phenols/alcohols with different steric and electronic properties to afford the desired N-aryl amines/diaryl ethers/alkyl aryl ethers in good to excellent yield (70-94%).
- Majumder, Arpi,Gupta, Ragini,Mandal, Mrinmay,Babu, Madhu,Chakraborty, Debashis
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- Iron-mediated direct arylation of unactivated arenes in air
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Biaryls are a common motif in both natural and synthetic chemicals. Several methods have recently been reported for the preparation of these compounds using direct arylation catalyzed by iron, other base metals, or transition-metal-free systems. To date, these methods have all required inert and/or forcing conditions, which limited their application in routine organic synthesis. In this article we report a protocol for direct arylation using a convenient FeCl3/1,10-phenanthroline system as precatalyst. The reaction proceeds under mild conditions (100 °C), under air, and with non-distilled solvent. A simple, environmentally benign catalytic system based on iron trichloride and phenanthroline has been developed for the direct arylation of unactivated arenes with aryl halides under air. Copyright
- Huang, Yuxing,Moret, Marc-Etienne,Klein Gebbink, Robertus J. M.
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supporting information
p. 3788 - 3793
(2014/06/24)
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- Preparation and catalytic performance of perfluorosulfonic acid-functionalized carbon nanotubes
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Perfluorosulfonic acid-functionalized carbon nanotubes were prepared by liquid deposition of the perfluorosulfonic acid-polytetrafluoroethylene copolymer and characterized by N2 adsorption, scanning electron microscopy, transmission electron mi
- Zhang, Mengxiao,Li, Cuican,Hua, Weiming,Yue, Yinghong,Gao, Zi
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p. 1874 - 1882
(2015/09/28)
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- Enhanced activity over alkyl/aryl functionalized porous pillared-zirconium phosphates in liquid-phase reaction
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A series of porous pillared-zirconium phosphates functionalized with methyl, ethyl, propyl and phenyl groups were prepared and characterized by SEM, 29Si MAS NMR, TG and N2 adsorption. Their total surface acidity and accessible one were measured by potentiometric titration of n-butylamine and liquid phase 2,6-di-tert-butyl-pyridine adsorption, respectively. The catalytic behaviors of these hybrid materials for alkylation of hydroquinone and esterification of lauric acid were compared. Not the total acid sites but the accessible ones play a crucial role in both reactions of alkylation and esterification. The accession for acid sites can be enhanced by the introduction of alkyl/aryl groups, due to the improved hydrophobicity of the surface.
- Liu, Ke,Wang, Xueyan,Ding, Shengda,Li, Ying,Hua, Weiming,Yue, Yinghong,Gao, Zi
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- Solvent free liquid-phase alkylation of phenol over solid sulfanilic acid catalyst
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Sulfanilic acid was immobilized onto rice husk ash via 3-(chloropropyl) triethoxy-silane to form an acidic solid catalyst denoted as RHAPhSO 3H. The BET surface area was found to be 308 m2 g -1. Pyridine adsorption study revealed the presence of Br?nsted acid sites. The EDX analysis showed the presence of S (10.88%) and N (10.37%). The 29Si MAS NMR showed the presence of T 2, T3, Q3 and Q4 silicon centres. The three carbon atoms of the propyl group were evident from the 13C MAS NMR together with a series of chemical shifts consistent with the presence of the benzene ring. In the alkylation of phenol using RHAPhSO3H as the catalyst resulted in 95% conversion of tert-butyl alcohol at 120 °C with 52% selectivity towards 4-tert-butylphenol. The catalyst was reused several times without significant loss of catalytic activity.
- Adam, Farook,Hello, Kasim Mohammed,Ali, Tammar Hussein
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experimental part
p. 42 - 49
(2012/02/01)
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- PROCESS FOR PRODUCING A T-BUTYL PHENOL FROM A C4 RAFFINATE STREAM
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This invention relates to processes for producing various t-butyl phenols, such as 2,6-di-tert-butyl phenol and ortho-tert-butyl phenol, by selectively reacting phenol or a substituted phenol with an isobutylene-containing C4 raffinate stream. The 2,6-di-tert-butyl phenol and ortho-tert-butyl phenol can be transalkylated to form other tert-butyl phenols, such as para-tert-butyl phenol, 2,4-di-tert-butyl phenol.
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Page/Page column 11
(2011/06/25)
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- An eco-sustainable erbium(III) triflate catalyzed formation and cleavage of tert -butyl ethers
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An eco-compatible method, which permits the formation or cleavage of tert-butyl ethers of alcohols and phenols, is proposed. The protection step is performed in solvent-free conditions at room temperature using catalytic amount of Er(OTf)3. The catalyst is easily- recovered from the aqueous phase and reused several times without significant loss of activity. The deprotection step developed is also highly eco-friendly since the tert-butyl group is removed very quickly from alcohols and phenols in methanol using MW irradiation-. Georg Thieme Verlag Stuttgart · New York.
- Procopio, Antonio,Costanzo, Paola,Curini, Massimo,Nardi, Monica,Oliverio, Manuela,Paonessa, Rosina
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experimental part
p. 73 - 78
(2011/03/19)
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- Gold(I)-catalyzed direct C-H arylation of pyrazine and pyridine with aryl bromides
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An efficient procedure for the direct C-H arylation of electron-poor aromatics such as pyrazine and pyridine with aryl bomides is described. In the presence of catalytic amount of Cy3PAuCl and with the use of t-BuOK as base, pyrazine undergoes the direct C-H arylation with aryl bromides at 100 °C, and the yields of the arylated products depend on the nature of aryl bromides. In the cases of electron-rich aryl bromides used, the arylated pyrazines can be obtained in good to high yields. For electron-poor aryl bromides, the addition of AgBF4 is the crucial point to accelerate the coupling reaction to give the arylated products in moderate yields. Pyridine also reacts with electron-rich aryl bromides catalyzed by Cy3PAuCl to give a mixture of arylated regioisomers in moderate yield. However, in order to realize the direct C-H arylation of pyridine with electron-poor aryl bromides, the addition of silver salt as additive and a milder reaction temperature (60 °C) are required.
- Li, Ming,Hua, Ruimao
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supporting information; experimental part
p. 1478 - 1481
(2009/06/08)
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- A convenient synthesis of tert-butyl ethers under microwave condition
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Synthesis of tert-butyl ethers from various alcohols and substituted phenols can be achieved using tert-butyl bromide in the presence of basic lead carbonate as a catalyst under microwave irradiation in absence of solvent. The catalyst is easily recovered via filtration and reused up to three times without appreciable loss of activity.
- Mahammed,Keshava Murthy,Mohana Raju
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p. 575 - 578
(2008/09/20)
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- Efficient synthesis of tert-butyl ethers under solvent-free conditions
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A simple and efficient synthesis of tert-butyl ethers from various alcohols and substituted phenols using tert-butyl bromide in the presence of basic lead carbonate as a catalyst. The catalyst is easily recovered via filtration and can be reused up to three times without appreciable loss of activity. Copyright Taylor & Francis Group, LLC.
- Rai, Neithnadka Premsai,Arunachalam, Pirama Nayagam
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p. 2891 - 2896
(2008/02/13)
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- Copper(II)-catalyzed O-phenylation of alcohols with organobismuth(V) reagents: A convenient method for the synthesis of simple tert-alkyl phenyl ethers
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A convenient method for copper(II)-catalyzed O-phenylation of simple alcohols with organobismuth(V) compounds under mild conditions is described. Treatment of tetraphenylbismuth fluoride (Ph4BiF) with various simple alcohols in the presence of
- Mukaiyama, Teruaki,Sakurai, Naoto,Ikegai, Kazuhiro
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p. 1140 - 1141
(2007/10/03)
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- Alcohols and di-tert-butyl dicarbonate: How the nature of the Lewis acid catalyst may address the reaction to the synthesis of tert-butyl ethers
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The reaction between alcohols and Boc2O leads to the formation of ferf-butyl ethers and/or Boc-alcohols, depending on the nature of the Lewis acid catalyst. Product distribution is mainly tuned by the anionic part of the salt. Perchlorates and Inflates, anions with highly delocalized negative charge, give prevalent or exclusive ether formation. On the other hand, Boc alcohols are the main or exclusive products with un-delocalized isopropoxide or low-delocalized acetate ions. The metal ion influences only the reaction rate, roughly following standard parameters for calculating Lewis acidity. A reaction mechanism is supposed, and a series of experimental evidences is reported to support it. These studies allowed us to conclude that, to synthesize tert-butyl ethers, in reactions involving aliphatic alcohols, Mg(ClO4) 2 or Al(ClO4)3 represents the best compromise between costs and efficiency of the reaction, while, in reactions involving phenols, Sc(OTf)3 is the best choice, since aromatic tert-butyl ethers are not stable in the presence of perchlorates.
- Bartoli, Giuseppe,Bosco, Marcella,Carlone, Armando,Dalpozzo, Renato,Locatelli, Manuela,Melchiorre, Paolo,Sambri, Letizia
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p. 9580 - 9588
(2007/10/03)
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- Efficient t-butylation of phenol using the Wells-Dawson-type molybdovanadophosphoric heteropolyacid, H7P2Mo 17VO62, as catalyst
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Wells-Dawson heteropolyacid H7P2Mo 17VO62 proved to be an efficient catalyst for the alkylation of phenol with t-butyl alcohol. Under optimized conditions, 80°C and 4 h, H7P2Mo17VO62 loads as low as 0.15 mol % can be used leading to high phenol conversion. The main product, 2, 4-di-t-butylphenol, could be obtained in moderate selectivity.
- Li, Guixian,Wang, Bo,Wang, Jianming,Yan, Liang,Suo, Jishuan
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p. 173 - 176
(2007/10/03)
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- Unusual and unexpected reactivity of t-butyl dicarbonate (Boc2O) with alcohols in the presence of magnesium perchlorate. A new and general route to t-butyl ethers
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(Chemical Equation Presented) A new mild method for protecting alcohols as t-butyl ethers is reported. The reaction proceeds with Mg(ClO4) 2 and Boc2O and shows general applicability. The deprotection of t-butyl ethers has also been revisited. Preliminary results indicate the CeCl3·7H2O/Nal system is a very suitable catalyst for their removal.
- Bartoli, Giuseppe,Bosco, Marcella,Locatelli, Manuela,Marcantoni, Enrico,Melchiorre, Paolo,Sambri, Letizia
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p. 427 - 430
(2007/10/03)
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- Catalyst for aromatic C—O, C—N, and C—C bond formation
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The present invention is directed to a transition metal catalyst, comprising a Group 8 metal and a ligand having the structure wherein R, R′ and R″ are organic groups having 1-15 carbon atoms, n=1-5, and m=0-4. The present invention is also directed to a method of forming a compound having an aromatic or vinylic carbon-oxygen, carbon-nitrogen, or carbon-carbon bond using the above catalyst. The catalyst and the method of using the catalyst are advantageous in preparation of compounds under mild conditions of approximately room temperature and pressure.
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- Efficient method for the preparation of carboxylic acid alkyl esters or alkyl phenyl ethers by a new-type of oxidation-reduction condensation using 2,6-dimethyl-1,4-benzoquinone and alkoxydiphenylphosphines
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A new-type of oxidation-reduction condensation proceeded smoothly to afford carboxylic acid alkyl esters or alkyl phenyl ethers in good to high yields by combined use of alkoxydiphenylphosphines (1) having primary, bulky secondary or tertiary alkoxy groups, a mild quinone-type oxidant such as 2,6-dimethyl-1,4-benzoquinone (DMBQ) and carboxylic acids or phenols. Generally, alkoxydiphenylphosphines were prepared easily from chlorodiphenylphosphine (2) and alcohols in the presence of pyridine, and were isolated by distillation. On the other hand, the phosphines 1 were also prepared in situ from N,N-dimethylaminodiphenylphosphine (3a) and primary or secondary alcohols while primary, bulky secondary or tertiary alkoxydiphenylphosphines were alternatively formed in situ by adding 2 to the "BuLi-treated alcohols in order to perform the above reactions by a one-pot procedure from alcohols and nucleophiles. The reaction of thus formed 1, DMBQ and carboxylic acids or phenols afforded the corresponding alkylated products, including hindered secondary and tertiary alkylated ones, in good to high yields at room temperature. In the case of using chiral secondary alcohols, the corresponding carboxylic acid alkyl esters were obtained as well in high yields with perfect inversion of stereochemistry by SN2 replacement.
- Shintou, Taichi,Kikuchi, Wataru,Mukaiyama, Teruaki
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p. 1645 - 1667
(2007/10/03)
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- N- and O-arylation with triphenylantimony ortho-phenylenedioxides
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2,2,2-Triphenyl-1,3,2-benzodioxastibolanes react with alcohols, phenols, and amines in the presence of copper salts to give the corresponding O- and N-phenyl derivatives. Cyclic SbV dialkoxide containing an electron-withdrawing nitro group in t
- Stolyarova,Shavyrin,Finet,Fedorov
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p. 1736 - 1739
(2007/10/03)
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- Synthesis, characterization, and reactivity of monomeric, arylpalladium halide complexes with a hindered phosphine as the only dative ligand
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We report the isolation and structural characterization of several monomeric arylpalladium(II) halide complexes containing tri-tert-butyl phosphine, 1-adamantyl-di-tert-butylphosphine, or 2-adamantyl-di-tert-butylphosphine. X-ray diffraction, IR spectroscopy, and theoretical studies indicated that the complexes may be stabilized by agostic interactions. For example, the distance from the closest hydrogen atom to the palladium metal center in the X-ray structure of the 1-adamantyl-phenylpalladium bromide complex 1 was 2.26(3) A. The calculated Pd-H distance of 2.28 A and harmonic vibrational frequencies were in agreement with the measured distance, but Wiberg bond indices indicated only weak M-H-C interactions. Addition of 2-adamantyl-di-tert-butyl phosphine to 1 led to ligand exchange and formation of 2-adamantyl-di-tert-butyl phosphine complex 2. Addition of P(t-Bu)3 generated free aryl bromide and Pd[P(t-Bu)3]2. Reactivity of complex 1 with nucleophiles provided evidence of the intermediacy of these complexes in palladium-catalyzed cross-coupling reactions. Complex 1 reacted with amine and base to form the corresponding arylamine, with tert-butoxide to form the corresponding ether, with boronic acid and fluoride to form the corresponding biaryl, and with styrene to form stilbene. This complex also catalyzed the reaction of bromobenzene with diphenylamine in the presence of base to produce 94% of the amination product in 45 min at room temperature. This rate is comparable to the reaction rate of in situ generated catalysts. Copyright
- Stambuli, James P.,Buehl, Michael,Hartwig, John F.
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p. 9346 - 9347
(2007/10/03)
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- Air stable, sterically hindered ferrocenyl dialkylphosphines for palladium-catalyzed C-C, C-N, and C-O bond-forming cross-couplings
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Pentaphenylferrocenyl di-tert-butylphosphine has been prepared in high yield from a two-step synthetic procedure, and the scope of various cross-coupling processes catalyzed by complexes bearing this ligand has been investigated. This ligand creates a remarkably general palladium catalyst for aryl halide amination and for Suzuki coupling. Turnovers of roughly 1000 were observed for aminations with unactivated aryl bromides or chlorides. In addition, complexes of this ligand catalyzed the formation of selected aryl ethers under mild conditions. The reactions encompassed electron-rich and electron-poor aryl bromides and chlorides. In the presence of catalysts containing this ligand, these aryl halides coupled with acyclic or cyclic secondary alkyl- and arylamines, with primary alkyl- and arylamines, and with aryl- and primary alkylboronic acids. These last couplings provide the first general procedure for reaction of terminal alkylboronic acids with aryl halides without toxic or expensive bases. The ligand not only generates highly active palladium catalysts, but it is air stable in solution and in the solid state. Palladium(0) complexes of this ligand are also air stable as a solid and react only slowly with oxygen in solution.
- Kataoka, Noriyasu,Shelby, Quinetta,Stambuli, James P.,Hartwig, John F.
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p. 5553 - 5566
(2007/10/03)
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- Photochemistry of aryl tert-butyl ethers in methanol: The effect of substituents on an excited state cleavage reaction
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The photolysis of a set of 10 substituted aryl tert-butyl ethers, 8a-j, in methanol gave, as the major product, the corresponding phenol along with tert-butyl-substituted phenols resulting from photo-Fries reaction. The corresponding 4-cyanophenyl 1-adamantyl ether, 9, also gave 1-meth-oxyadamantane 16 (16%), indicating that, at least for this ether, some of the products were ion-derived. Quenching studies with 2,3-dimethylbutadiene for the tert-butyl ethers indicated that these reactions were occurring from the singlet excited state. Rate constants for the reaction, obtained from quantum yields and singlet lifetimes, were found to correlate reasonably well with σhv values, ρ = -0.77 (r = 0.975), a result that is unexpected for a reaction where the polarity of the bond breaking in the transition state is expected to be -O(δ-)···C(δ+).
- DeCosta,Bennett,Pincock,Pincock,Stefanova
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p. 4162 - 4168
(2007/10/03)
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- Protection of phenols as t-butyl ethers under mild conditions
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Zinc mediated selective O-y-butylation of phenols has been carried out in good to excellent yields under mild conditions. No trace of C-t-butylation was observed.
- Bandgar,Kasture
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p. 252 - 253
(2007/10/03)
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- Palladium/P(t-Bu)3-catalyzed synthesis of aryl t-butyl ethers and application to the first synthesis of 4-chlorobenzofuran
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Pd/P(t-Bu)3 catalyzed reaction of aryl halides with sodium t-butoxide effectively to give aryl t-butyl ethers. The high catalytic activity realized the formation of aryl t-butyl ethers from not only electron-deficient aryl halides but also electron-rich aryl halides. Moreover, the first synthesis of 4-chlorobenzofuran was attained utilizing the selective mono-t-butoxylation of aryl dihalide.
- Watanabe, Makoto,Nishiyama, Masakazu,Koie, Yasuyuki
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p. 8837 - 8840
(2007/10/03)
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- Thermal isomerization of t-butylphenyl ether
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Thermal isomerization of t-butylphenyl ether alone and in the presence of phenol was studied between 180 and 340°C at reaction times from 0.5 to 0.7 s. The experiments proved for the first time that the isomerization occurs through a homolytic process in the first step with the appearance of phenol and isobutene. The activation energy for the uncatalyzed process (8 kcal/mol) decreases considerably (to 2 kcal/mol) for thermal isomerization of t-butylphenyl ether in the presence of 10% phenol proving the catalytic activity of the latter.
- Bolocan, Ion,Filotti, Liviu,Cuiban, Flavian
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p. 209 - 213
(2007/10/03)
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- Acid-Catalyzed Hydrolysis of tert-Butyl Phenyl Ether. An Application of the Excess Acidity Method
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Hydrolysis of tert-butyl phenyl ether in aqueous perchloric acid solutions was studied by capillary GC.The activation entropy (67 J K-1 mol-1), the solvent deuterium isotope effect (kH/kD = 0.37) and the relative rate kt-BuOPh/kiPrOPh ca. 107) are in agreement with the unimolecular mechanism (A-1) of hydrolysis.The kinetic excess acidity method gives the pKSH+ values as -1.91+/-0.03 at 283 K and the m parameters as 2.02+/-0.02, which also accords only with the A-1 mechanism.The values are compared with those evaluated for the hydrolyses of several secondary alkyl phenyl ethers.
- Lajunen, Martti,Tanskanen-Lehti, Kirsi
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p. 861 - 864
(2007/10/02)
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- AN ORGANIC SOLID STATE REACTION: ALKYLATION OF AROMATIC SOLID SUBSTANCES BY ALKENES AND SOLID CATALYSTS
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Catalyzed alkylation of solid aromatic substances is envisaged.The solid phenol, isobutene gas reaction is carried out in the presence of solid catalysts.Two phosphoric acid and silica based catalysts were prepared and tested.The reactivity and selectivity of the solide phase reaction were determined as a function of the nature and quantity of the catalyst.The results are compared with those of the liquid state and the solution.A mechanism involving transfer of active entities from the solid catalyst to the solid organic reagent is proposed.
- Lamartine, Roger,Lamsouber, Fouad,Perrin, Robert
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p. 163 - 176
(2007/10/02)
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- Reaction of Ammonia with Accelerated Benzoyl Ions under Multiple-collision Conditions in a Triple Quadrupole Instrument
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The reaction of benzoyl ion with ammonia in multiple-collision conditions in the second quadrupole assembly of a triple quadrupole mass spectrometer at (laboratory) ion kinetic energies from 0 to 20 eV produced the even-electron ions +, m>+ (m=0,1) and + (n=0,1,2,3) and the odd-electron ions p>+. (p=0,1).Thermochemical information could not be obtained under multiple-collision conditions: both exotermic and endotermic reactions were observed, with no translational-energy onset measurable for the endothermic pr/cesses, nor decrease in the yield of the exothermic processes at high energies.The behaviour of cluster-ions intensities as pressure varied was qualitatively as expected.There are pressure and energy regions where spectra change little; if this feature were to be general, it would point to some utility for these conditions in qualitative analysis.
- White, Earl L.,Tabet, Jean-Claude,Bursey, Maurice M.
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p. 132 - 139
(2007/10/02)
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- NUCLEOPHILIC SUBSTITUTION OF ALKYL HALIDES BY ZINC SALTS-3 PREPARATION OF TERTARY ALKYL ESTERS AND ETHERS UNDER NON-SOLVOLYTIC CONDITIONS
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Zinc salts of carboxylic acids, phenols and alcohols are found to react with tertiary alkyl halides in nonpolar solvents and in presence of a base yielding the corresponding esters and ethers in moderate to good yields.
- Ravindranath, B.,Srinivas, P.
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p. 1623 - 1628
(2007/10/02)
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- A NEW SYNTHETIC METHOD FOR THE PREPARATION OF TERT-BUTYL ARYL ETHERS
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A facile synthesis for the preparation of tert-butyl aryl ethers from phenols under basic conditions is described.
- Mohacsi, Erno
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p. 827 - 832
(2007/10/02)
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- FLUORIDE SALTS ON ALUMINA AS REAGENTS FOR ALKYLATION OF PHENOLS AND ALCOHOLS.
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THE EFFECTIVENESS OF ALKALI METAL FLUORIDES IMPREGNATED ON ALUMINA AS A REAGENT FOR PROMOTING ALKYLATION WAS OPTIMIZED WITH RESPECT TO THE METAL CATION, THE AMOUNT OF IMPREGNATION, AND THE REACTION SOLVENT. POTASSIUM OR CAESIUM FLUORIDE ONALUMINA IN ACETONITRILE OR 1,2-DIMETHOXYETHANE WAS CONCLUDED TO BE THE BEST REACTION SYSTEM FOR GENERAL USE. O-ALKYLATION OF SUBSTITUTED PHENOLS, PRIMARY AND SECONDARY ALCOHOLS, AND A GLYCOL WAS CARRIED OUT MOSTLY IN GOOD YIELDS UNDER MILDCONDITIONS WITH SIMPLE EXPERIMENTAL PROCEDURES.
- ANDO,YAMAWAKI,KAWATE,SUMI,HANAFUSA
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p. 2504 - 2507
(2007/10/02)
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