- Electrochemical cross-coupling reactions of sodium arenesulfinates with thiophenols and phenols
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A green electrochemical oxidative cross-coupling protocol for the generation of thiosulfonates and sulfonate esters using sodium arenesulfinates and thiophenols/phenols is disclosed. The protocol involves using inorganic and non-toxic NaI as both redox catalyst and supporting electrolyte at room temperature without oxidant and base. The reactions provide good yields of products and tolerate broad substrate scope. The mechanistic studies revealed that the reactions proceed via a radical pathway for the formation of SO2–S and SO2–O bonds.
- Ma, Jinfeng,Xu, Pan,Zhong, Zijian,Zhou, Aihua
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supporting information
(2021/10/26)
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- Palladium-Catalyzed Cyanation under Mild Conditions: A Case Study to Discover Appropriate Substrates among Halides and Pseudohalides
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A case study has been effectively carried out to identify a suitable substrate among halides and pseudohalides for the palladium-catalyzed cyanation reactions under mild conditions. Among the various substrates considered for evaluation, aryl pentafluorobenzenesulfonates and nonaflates were identified to be the best substrates when compared to corresponding halides and pseudohalides. The substoichiometric use of nontoxic, environmentally benign potassium hexacyanoferrate as a cyanide source and exceptionally milder conditions further highlights the significance of the protocol developed. A wide range of electronically biased and sterically challenging substrates provided the corresponding the nitriles in good to excellent yields.
- Rajendra, Merla Arjuna,Sunil,Sajith, Ayyiliath Meleveetil,Joy, Muthipeedika Nibin,Bakulev, Vasiliy A.,Haridas, Karickal Raman
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supporting information
p. 1629 - 1633
(2020/09/15)
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- Chromatography-Free and Eco-Friendly Synthesis of Aryl Tosylates and Mesylates
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Two chromatography-free and eco-friendly protocols have been developed to synthesize aryl tosylates and mesylates by the tosylation and mesylation of the corresponding hydroxyarenes, respectively. These protocols are superior to other known ones regarding
- Lei, Xiangyang,Jalla, Anusha,Abou Shama, Mhd A.,Stafford, Jamie M.,Cao, Billy
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supporting information
p. 2578 - 2585
(2015/09/01)
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- Competing pathways in the photogeneration of didehydrotoluenes from (Trimethylsilylmethyl)aryl sulfonates and phosphates
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The scope of the photochemical generation of a,n-didehydrotoluene diradicals from aryl sulfonates and phosphates and their chemistry are explored. The thermally inaccessible a,2- and a,4-intermediates are efficiently obtained by irradiation of ortho- and para-(trimethylsilylme-thyl)phenyl triflates through heterolytic splitting of the ester anion from the substrate in the triplet state. Triplet phenyl cations are formed and the loss of trimethylsilyl cation from them affords the desired diradicals (3Me3SiCH2C6H4-OZ→ 3Me3SiCH2C6H4+→CH2C6H4). Triplet sensitization is required, for which acetone is used throughout. Direct irradiation leads, on the contrary, to photo-Fries fragmentation (1Me3SiCH2C6H4O-Z→Me3SiCH2C6H4O· + Z). With mesylates, where ester cleavage is less convenient, a further competition from the triplet is direct desilylation. Didehydrotoluenes are also obtained from the corresponding phosphates, although with poor efficiency.
- Crespi, Stefano,Ravelli, Davide,Protti, Stefano,Albini, Angelo,Fagnoni, Maurizio
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p. 17572 - 17578
(2015/02/18)
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- Palladium-catalyzed intra-and intermolecular C-H arylation using mesylates: Synthetic scope and mechanistic studies
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This paper describes the development of Pd-catalyzed inter-and intramolecular direct arylation using mesylates. Furthermore, a sequential mesylation/arylation protocol using phenols as substrates is described. These transformations are general with respect to the electronics of the C-H substrates and allow for the synthesis of diverse heterocyclic motifs in good yields. Both arenes and heteroarenes efficiently participate in these reactions. Preliminary mechanistic studies are presented for both inter-and intramolecular arylations.
- Ferguson, Devin M.,Rudolph, Stacey R.,Kalyani, Dipannita
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p. 2395 - 2401
(2014/07/21)
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- Decarboxylative cross-coupling of mesylates catalyzed by copper/palladium systems with customized imidazolyl phosphine ligands
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The activation of the inert C-O bonds in mesylates through the use of a new class of imidazolyl phosphines allows the decarboxylative coupling of aryl mesylates as well as polysubstituted alkenyl mesylates. Variation of the ligands leads to two complementary methods providing the corresponding biaryls and polysubstituted olefins in good yields. Copyright
- Song, Bingrui,Knauber, Thomas,Goo?en, Lukas J.
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supporting information
p. 2954 - 2958
(2013/04/11)
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- Mechanistic insight into the formal [1,3]-migration in the thermal claisen rearrangement
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The thermal formal [1,3]-sigmatropic shift of allyl aryl ethers has been studied in depth experimentally with the aid of the density functional theory (DFT) calculations of the B3LYP function. Three mechanistic possibilities, referred to as the radical, ionic, and concerted mechanisms, have previously been put forth to explain the thermal [1,3]-rearrangement process. However, the intercrossing and radical trapping experiments indicate the rearrangement is an intramolecular process. The computational studies reveal that the concerted C[1,3]-sigmatropic shift suffered from a higher energetic barrier to allow the rearrangement to proceed under the conditions used. However, a tandem O[1,3]-sigmatropic shift with a configuration inversion of the oxygen atom and [3,3]-sigmatropic shift (the Claisen rearrangement) is the most likely pathway for the formal [1,3] rearrangement. Furthermore, the rearrangement experiments with a designed optically active substrate and O[1,3]-sigmatropic shift examples verify the new cascade rearrangement. In addition, computational and experimental studies indicate that water molecule assists the proton shift during the isomerization. The combined methods provide the new insight into the mechanism of the thermal formal [1,3]-migration in the Claisen rearrangement and the novel O[1,3]-sigmatropic shift as well.
- Hou, Shili,Li, Xinyao,Xu, Jiaxi
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p. 10856 - 10869
(2013/02/23)
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- Nickel catalyzed cross-coupling of aryl C-O based electrophiles with aryl neopentylglycolboronates
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The efficiency of mesylates, sulfamates, esters, carbonates, carbamates, and methyl ethers as C-O-based electrophiles attached to the 1- or 2-position of naphthalene and to activated and nonactivated phenyl substrates was compared for the first time in Ni-catalyzed cross-coupling with phenyl neopentylglycolboronates containing electron-rich and electron-deficient substituents in their para-position. These experiments were performed in the presence of four different Ni(II)- and Ni(0)-based catalysts. Ni(II)-based catalysts mediate the cross-coupling of most 2-naphthyl C-O electrophiles with both arylboronic acids and with neopentylglycolboronates when K 3PO4 is used as base. The same catalysts are not efficient when CsF is used as base. However, Ni(0)-based catalysts exhibit selective efficiency, and when reactive, their efficiency is higher than that of Ni(II)-based catalysts in the presence of both K3PO4 and CsF. These results provide both reaction conditions for the cross-coupling, and for the elaboration of orthogonal cross-coupling methodologies of various C-O based electrophiles with aryl neopentylglycolboronates. With the exception of mesylates and sulfamates the efficiency of all other 2-naphthyl C-O electrophiles was lower in cross-coupling with aryl neopentylglycolboronates than with arylboronic acids
- Leowanawat, Pawaret,Zhang, Na,Percec, Virgil
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experimental part
p. 1018 - 1025
(2012/03/22)
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- Neopentylglycolborylation of aryl mesylates and tosylates catalyzed by Ni-based mixed-ligand systems activated with Zn
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(Chemical Presented) The mixed-ligand system NiCl2(dppp)/dppf is shown to be an effective catalyst for the neopentylglycolborylation of ortho-, meta-, and para-substituted electron-rich and electrondeficient aryl mesylates and tosylates. The ad
- Wilson, Daniela A.,Wilson, Christopher J.,Moldoveanu, Costel,Resmerita, Ana-Maria,Corcoran, Patrick,Hoang, Lisa M.,Rosen, Brad M.,Percec, Virgil
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supporting information; experimental part
p. 1800 - 1801
(2010/04/24)
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- A novel synthesis of aryl mesylates via one-pot demethylation-mesylation of aryl methyl ethers using a mixture of phosphorus pentoxide in methanesulfonic acid
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A simple, efficient, and new method has been developed for the synthesis of aryl mesylates via one-pot demethylation-mesylation of aryl methyl ethers. Treatment of a variety of aryl methyl ethers with a mixture of phosphorus pentoxide in methanesulfonic a
- Kaboudin, Babak,Abedi, Yaghoub
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experimental part
p. 2025 - 2028
(2009/12/26)
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- A simple preparation of aryl methanesulfonates by thermal decomposition of dry arenediazonium O-benzenedisulfonimides in methanesulfonic acid
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Aryl methansulfonates 3 (18 examples) were easily prepared by thermal decomposition of dry arenediazonium o-benzenedisulfonimides 1 in methanesulfonic acid (2). The reactions were carried out at temperatures between 60 and 120°C for times between 0.5 and 8 h. The aryl methanesulfonates were obtained in reproducible yield of 70-90%, with few exceptions. In all cases the o-benzenedisulfonimide (4) could be recovered in good yields which can then be reused to prepare the salts 1. When thermal decomposition of salts 1 was carried out in trifluoromethanesulfonic acid (5) at 90-120°C for 1-2 h, aryl trifluoromethanesulfonates 6 were obtained in 73-78% yield (3 examples).
- Barbero, Margherita,Degani, Iacopo,Dughera, Stefano,Fochi, Rita,Perracino, Paolo
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- Aryl Mesylates in Metal-Catalyzed Homocoupling and Cross-Coupling Reactions. 1. Functional Symmetrical Biaryls from Phenols via Nickel-Catalyzed Homocoupling of Their Mesylates
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Aryl sulfonates including mesylate derived from phenols are converted in high yields to biaryls by homocoupling in the presence of catalytic amounts of zero-valent nickel catalysts generated in situ.This reaction provides the most convenient method for the synthesis of many functional symmetrical biaryls and was applied to the preparation of 2,2'-, 3,3'-, and 4,4'-disubstituted biphenyls and other biaryls.The influence of the electronic and steric effects of substituents attached in the ortho, meta, and para positions of aryl sulfonates and the nature of the sulfonate leaving group on the yield of homocoupled product as well as their influence on the extent of various side reactions were investigated.In addition, the influence of the effects of the polarity and dryness of solvent, halide ion source and concentration, and ratio of catalyst and ligand to aryl sulfonate are discussed.
- Percec, Virgil,Bae, Jin-Young,Zhao, Mingyang,Hill, Dale H.
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p. 176 - 185
(2007/10/02)
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- MECHANISM OF THE REACTION OF (ARYLOXY)TRIMETHYLSTANNANE WITH METHANESULFONYL CHLORIDE - SOLVENT AND SUBSTITUENT EFFECTS ON THE RATE OF THE REACTION.
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A kinetic study has been conducted on the reactions of (aryloxy)trimethylstannanes with methanesulfonyl chloride giving chlorotrimethylstannane and aryl methanesulfonates. The reaction was found to obey a second order kinetic equation. The solvent effect on the rate of the reaction appeared obscure although a small rate enhancement was observed in a polar solvent. Substituent effect of the aryloxyl group was found to be dependent on the solvent used while a clear isokinetic relationship was observed. A charge separated four-center transition state has been suggested for the reaction.
- Kozuka,Yamaguchi,Tagaki
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p. 573 - 576
(2007/10/02)
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- ALKANESULFONYLATION REACTIONS IX. CATALYTIC EFFECT OF PYRIDINES ON THE MESYLATION OF PHENOLS
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The kinetics of the mesylation of seven substituted phenols in the presence of 13 derivatives of pyridine in benzene at 50 deg C were investigated.It was shown that in this case, in contrast to catalysis by trialkylamines, the elimination-addition (sulfen
- Skrypnik, Yu. G.,Bezrodnyi, V. P.
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p. 2056 - 2063
(2007/10/02)
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- THE MECHANISM OF THE REACTION OF ARYLOXYTRIMETHYLSTANNANE WITH METHANESULFONYL CHLORIDE
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A kinetic study has been conducted for the reaction of aryloxytrimethylstannane with methanesulfonyl chloride.Substituent effect was found to be dependent on the solvent and obscure solvent effect was observed.A mechanism has been suggested involving nearly concerted four-center transition state.
- Kozuka, Seizi,Yamaguchi, Shigeru,Tagaki, Waichiro
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p. 1299 - 1300
(2007/10/02)
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- ALKANESULFONYLATION REACTIONS. IV. MESYLATION OF PHENOLS IN THE PRESENCE OF TRIETHYLAMINE
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The kinetics of the acylation of five substituted phenols by methanesulfonyl chloride in the presence of triethylamine in benzene were investigated by GLC and potentiometric titration.The reaction is of first order in the sulfonyl chloride and triethylami
- Bezrodnyi, V. P.,Skrypnik, Yu. G.,Baranov, S. N.
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p. 1581 - 1586
(2007/10/02)
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