- Ni-Catalyzed Cross-Electrophile Coupling of Aryl Triflates with Thiocarbonates via C-O/C-O Bond Cleavage
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A nickel-catalyzed reductive coupling of aryl triflates with thiocarbonates is reported here. Both electron-rich and -deficient aryl C(sp2)-O electrophiles as well as a class of O-tBu S-alkyl thiocarbonates are compatible with the optimized reaction conditions, as evidenced by 49 examples. The reaction also proceeds with good chemoselective cleavage of the C-O bond with regard to thioesters. This work broadens the scope of nickel-catalyzed reductive cross-electrophile coupling reactions.
- Zhu, Zhaodong,Gong, Yuxin,Tong, Weiqi,Xue, Weichao,Gong, Hegui
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supporting information
p. 2158 - 2163
(2021/04/05)
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- Palladium-Catalyzed Reductive Carbonylation of (Hetero) Aryl Halides and Triflates Using Cobalt Carbonyl as CO Source
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An efficient protocol for the reductive carbonylation of (hetero) aryl halides and triflates under CO gas-free conditions using Pd/Co2(CO)8 and triethylsilane has been developed. The mild reaction conditions, enhanced chemoselectivity and, easy access to heterocyclic and vinyl carboxaldehydes highlights its importance in organic synthesis.
- Dogga, Bhushanarao,Joseph, Jayan T.,Kumar, C. S. Ananda
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supporting information
p. 309 - 313
(2020/12/23)
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- C(sp3) -C(sp2) Method for constructing key and β - aryl amino acid preparation method
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The invention provides C. (sp3) - C(sp2) A method for constructing a key and β -aryl amino acid relates to the technical field of chemical substance synthesis and transition metal application, which comprises β-C amino acid. (sp3) Ring carbon C in place of phenolic hydroxyl group(sp2) A method of constructing C-C keys by direct coupling. The process will contain inactive β-C. (sp3) Amino acids of - H and ligands L of specific structure1 The tetradentate chelate is generated by complexation with bivalent nickel, and the amino acid labile β-C is completed under the catalysis of palladium with phenolic ester under basic conditions. (sp3) - H Aryl, proton transfer and the like are reacted to achieve C. (sp3) - C(sp2) Construction of a bond, finally hydrolytically releasing β-C aryl amino acid and ligand L1 C. (sp3) - C(sp2) The key construction method is simple and convenient to operate. The method has the advantages of low cost, strong reaction universality, high yield and stereoselectivity. The synthetic method provides a novel method for preparing various non-natural β - aryl amino acids, and provides a novel method for amino acidification/peptide modification of phenolic compounds with biological activity, and provides a novel approach and selection for the design and synthesis of new drugs.
- -
-
Paragraph 0037-0038; 0046
(2021/10/27)
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- Dual Photoredox-/Palladium-Catalyzed Cross-Electrophile Couplings of Polyfluoroarenes with Aryl Halides and Triflates
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A visible-light photoredox-/Pd-catalyzed cross-electrophile arylation of polyfluoroarenes with aryl halides and triflates in the presence of dialkylamines is reported for the first time. This synergistic protocol affords access to a series of fluorodiaryls from easily available starting materials under mild and operationally simple conditions. A series of mechanistic experiments, including the stoichiometric reactions of a ligated (aryl)Pd complex, Stern-Volmer fluorescence quenching studies, cyclic voltammetry studies, and UV-vis spectroscopy, were performed to elucidate the potential catalytic pathway in this synergistic process.
- Qin, Jian,Zhu, Shengqing,Chu, Lingling
-
supporting information
p. 2246 - 2252
(2021/04/02)
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- Nickel-Catalyzed Arylation/Alkenylation of tert-Cyclobutanols with Aryl/Alkenyl Triflates via a C - C Bond Cleavage
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Herein, we first present a nickel-catalyzed arylation and alkenylation of tert-cyclobutanols with aryl/alkenyl triflates via a C-C bond cleavage. An array of γ-substituted ketones was obtained in moderate-to-good yields, thus featuring earth-abundant nick
- Wang, Zhen,Hu, Yuanyuan,Jin, Hongwei,Liu, Yunkui,Zhou, Bingwei
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p. 466 - 474
(2020/12/22)
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- Palladium-Catalyzed Synthesis of N, N-Dimethylanilines via Buchwald-Hartwig Amination of (Hetero)aryl Triflates
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This work delineates the synthesis of N,N-dimethylaniline derivatives from dimethylamines and aryl triflates. The palladium-catalyzed C-N bond formation proceeds in excellent yields, using an unsophisticated catalytic system, a mild base, and triflates as electrophiles, which are readily available from inexpensive phenols. N,N-Dimethylanilines are multifunctional reaction partners and represent useful but underutilized building blocks in organic synthesis.
- Pospech, Jola,Taeufer, Tobias
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p. 7097 - 7111
(2020/06/27)
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- Base-promoted selective O-phosphorylation of aryl triflates with P(O)-H compounds
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Compared to previous transition metal-catalyzed C-phosphorylation reactions for constructing C–P bonds, in the absence of transition metal catalysts and ligands, a direct O-phosphorylation of aryl triflates selectively occurred with P(O)-H compounds in the presence of a base via the construction of O–P bonds. This transformation proceeds under simple and mild conditions, and provides a new method for the preparation of valuable organophosphoryl compounds from readily available P(O)-H compounds and triflates.
- Wang, Mingyue,Yang, Jia,Wang, Shuai,Zhong, Hong
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supporting information
(2020/05/05)
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- Palladium-Catalyzed Cyclobutanation of Aryl Sulfonates through both C-O and C-H Cleavage
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A palladium-catalyzed cyclobutanation of aryl sulfonates with strained alkenes has been developed. The methodology is featured to achieve the cleavage of both C-O and C-H bonds of phenol derivatives in one pot. Under the reaction conditions, in addition t
- Zhang, Liangwei,Liu, Long,Huang, Tianzeng,Dong, Qizhi,Chen, Tieqiao,Chen, Tieqiao
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p. 2189 - 2196
(2020/06/05)
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- First Study of the Thermal and Storage Stability of Arenediazonium Triflates Comparing to 4-Nitrobenzenediazonium Tosylate and Tetrafluoroborate by Calorimetric Methods
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Herein, for the first time, using isothermal flow calorimetry and differential scanning calorimetry (DSC)/thermal gravimetric analysis (TGA), we have determined the thermal decomposition energies for the number of solid arenediazonium triflates comparing to 4-nitrobenzene tosylate and 4-nitrobenzentetrafluoroborate. The kinetics of thermal decomposition, activation energies, and half-lives of the studied diazonium salts (DSs) were found. Using gas chromatography-mass spectrometry (MS) and liquid chromatography-MS, we have elucidated the products formed during thermolysis of the investigated DSs. By density functional theory quantum chemical calculations at the B3LYP/aug-cc-pVDZ level of theory, we simulated the thermodynamics of decomposition reactions proceeding via substitution of the diazonium group by corresponding nucleophiles. The method applied predicted the decomposition energies of all the studied compounds fairly precise, except for 2-nitrobenzene diazonium triflate. It has been found that 4-nitrobenzene diazonium triflate has increased storage stability under normal conditions comparing to the corresponding tosylate and tetrafluoroborate. The experimental and theoretical results demonstrated that comparing to DSC/TGA, isothermal flow calorimetry more adequately reflects the energetics of the thermal decomposition of DSs and their storage stability under normal conditions.
- Bondarev, Alexander A.,Naumov, Evgeny V.,Kassanova, Assiya Zh.,Krasnokutskaya, Elena A.,Stankevich, Ksenia S.,Filimonov, Victor D.
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p. 2405 - 2415
(2019/10/11)
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- Reductive Coupling between C-N and C-O Electrophiles
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The cross-electrophile reaction is a promising strategy for C-C bond formation. Recent studies have focused mainly on reactions with organic halides. Here we report a coupling reaction between C-N and C-O electrophiles that demonstrates the possibility of constructing a C-C bond via C-N and C-O cleavage. Several reactions between benzyl/aryl ammonium salts and vinyl/aryl C-O electrophiles have been studied. Preliminary mechanistic studies revealed that the benzyl ammoniums were activated through a radical mechanism.
- He, Rong-De,Li, Chun-Ling,Pan, Qiu-Quan,Guo, Peng,Liu, Xue-Yuan,Shu, Xing-Zhong
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supporting information
p. 12481 - 12486
(2019/09/04)
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- Transition-Metal-Free C-C, C-O, and C-N Cross-Couplings Enabled by Light
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Transition-metal-catalyzed cross-couplings to construct C-C, C-O, and C-N bonds have revolutionized chemical science. Despite great achievements, these metal catalysts also raise certain issues including their high cost, requirement of specialized ligands, sensitivity to air and moisture, and so-called "transition-metal-residue issue". Complementary strategy, which does not rely on the well-established oxidative addition, transmetalation, and reductive elimination mechanistic paradigm, would potentially eliminate all of these metal-related issues. Herein, we show that aryl triflates can be coupled with potassium aryl trifluoroborates, aliphatic alcohols, and nitriles without the assistance of metal catalysts empowered by photoenergy. Control experiments reveal that among all common aryl electrophiles only aryl triflates are competent in these couplings whereas aryl iodides and bromides cannot serve as the coupling partners. DFT calculation reveals that once converted to the aryl radical cation, aryl triflate would be more favorable to ipso substitution. Fluorescence spectroscopy and cyclic voltammetry investigations suggest that the interaction between excited acetone and aryl triflate is essential to these couplings. The results in this report are anticipated to provide new opportunities to perform cross-couplings.
- Liu, Wenbo,Li, Jianbin,Querard, Pierre,Li, Chao-Jun
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supporting information
p. 6755 - 6764
(2019/05/06)
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- Solvent-free ruthenium-catalysed triflate coupling as a convenient method for selective azole-o-C-H monoarylation
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Metal-catalysed ortho-directed C-H functionalization usually faces selectivity issues in the competition between mono- and disubstitution processes. We report herein the ruthenium-catalysed N-directed C-H monoarylation of arylpyrazoles with a selectivity
- Abidi, Oumaima,Boubaker, Taoufik,Hierso, Jean-Cyrille,Roger, Julien
-
supporting information
p. 5916 - 5919
(2019/06/24)
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- Palladium-Catalyzed Chemoselective Negishi Cross-Coupling of Bis[(pinacolato)boryl]methylzinc Halides with Aryl (Pseudo)Halides
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We describe a palladium-catalyzed chemoselective Negishi cross-coupling of a bis[(pinacolato)boryl]methylzinc halide with aryl (pseudo)halides. This reaction affords an array of benzylic 1,1-diboronate esters, which can serve as useful synthetic handles f
- Lee, Hyojae,Lee, Yeosan,Cho, Seung Hwan
-
supporting information
p. 5912 - 5916
(2019/08/20)
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- Enantioselective Synthesis of α-Allyl Amino Esters via Hydrogen-Bond-Donor Catalysis
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We report a chiral-squaramide-catalyzed enantio- and diastereoselective synthesis of α-allyl amino esters. The optimized protocol provides access to N-carbamoyl-protected amino esters via nucleophilic allylation of readily accessible α-chloro glycinates. A variety of useful α-allyl amino esters were prepared, including crotylated products bearing vicinal stereocenters that are inaccessible through enolate alkylation, with high enantioselectivity (up to 97% ee) and diastereoselectivity (>10:1). The reactions display first-order kinetic dependence on both the α-chloro glycinate and the nucleophile, consistent with rate-limiting C-C bond formation. Computational analysis of the uncatalyzed reaction predicts an energetically inaccessible iminium intermediate, and a lower energy concerted SN2 mechanism.
- Bendelsmith, Andrew J.,Kim, Seohyun Chris,Wasa, Masayuki,Roche, Stéphane P.,Jacobsen, Eric N.
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supporting information
p. 11414 - 11419
(2019/08/20)
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- Negishi coupling reactions with [11C]CH3I: A versatile method for efficient 11C-C bond formation
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Herein, we present a fast, efficient and general one-pot method for the synthesis of 11C-labelled compounds via the Negishi cross-coupling reaction. Our approach, based on the in situ formation of [11C]CH3ZnI and subsequent reaction with aryl halides or triflates, has proven efficient to synthesize [11C]thymidine, a biologically relevant compound with potential applications as a proliferation marker. Theoretical calculations have shown irreversible formation of a tetracoordinated nucleophilic 11C-Zn(ii) reagent and electronic requirements for an efficient Negishi coupling.
- Rejc, Luka,Gómez-Vallejo, Vanessa,Alcázar, Jesús,Alonso, Nerea,Andrés, José Ignacio,Arrieta, Ana,Cossío, Fernando P.,Llop, Jordi
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supporting information
p. 4398 - 4401
(2018/05/03)
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- The Directed ortho Metalation (D o M)-Cross-Coupling Connection: Synthesis of Polyfunctional Biaryls
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A comparative evaluation of the combined directed ortho metalation (D o M)-Suzuki-Miyaura and D o M-Negishi cross-coupling reactions with aryl triflates for the synthesis of substituted biaryls is described. Both ortho -zinc and ortho -boron aryl directed
- Quesnelle, Claude A.,Snieckus, Victor
-
supporting information
p. 4413 - 4428
(2018/11/21)
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- Reactions of Arylsulfonate Electrophiles with NMe4F: Mechanistic Insight, Reactivity, and Scope
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This paper describes a detailed study of the deoxyfluorination of aryl fluorosulfonates with tetramethylammonium fluoride (NMe4F) and ultimately identifies other sulfonate electrophiles that participate in this transformation. 19F NMR spectroscopic monitoring of the deoxyfluorination of aryl fluorosulfonates revealed the rapid formation of diaryl sulfates under the reaction conditions. These intermediates can proceed to fluorinated products; however, diaryl sulfate derivatives bearing electron-donating substituents react very slowly with NMe4F. Based on these findings, aryl triflate and aryl nonaflate derivatives were explored, since these cannot react to form diaryl sulfates. Aryl triflates were found to be particularly effective electrophiles for deoxyfluorination with NMe4F, and certain derivatives (i.e., those bearing electron-neutral/donating substituents) afforded higher yields than their aryl fluorosulfonate counterparts. Computational studies implicate a similar mechanism for deoxyfluorination of all the sulfonate electrophiles.
- Schimler, Sydonie D.,Froese, Robert D. J.,Bland, Douglas C.,Sanford, Melanie S.
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p. 11178 - 11190
(2018/09/12)
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- Palladium nanoparticles: Chemoselective control for reductive Heck with aryl triflates and 2,3-dihydrofuran
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The reductive-Heck reaction offers a unique entry to formal Csp2-Csp3 cross-coupling reactions that proceed in the absence of a main group organometallic coupling partner. Consequently, further development of new variants would be transformative. Unfortunately, controlling the relative rates of the organopalladium intermediates has proven difficult with homogenous, single-site Pd catalysts. This work describes a selective reductive Heck reaction catalyzed by Pd-nanoparticles. The reaction works well with electron-deficient aryl triflates at room temperature in the absence of ligands. This work addresses some of the challenges found in the reductive-Heck literature.
- Rosas Vargas, Daisy,Cook, Silas P.
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supporting information
p. 3314 - 3317
(2018/05/04)
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- Catalytic Alkyne Arylation Using Traceless Directing Groups
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By using Pd0/Mandyphos, we achieved a three-component aminoarylation of alkynes to generate enamines, which are then hydrolyzed to either α-arylphenones or α,α-diarylketones. This Pd-catalyzed method overcomes established known pathways to enable the use of amines as traceless directing groups for C?C bond formation.
- Park, Jung-Woo,Kang, Bubwoong,Dong, Vy M.
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supporting information
p. 13598 - 13602
(2018/09/25)
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- A simple route to 1,4-addition reactions by Co-catalyzed reductive coupling of organic tosylates and triflates with activated alkenes
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An efficient Co-catalyzed 1,4-addition reaction of alkyl/aryl triflates and tosylates with activated alkenes is described. In this reaction, an air-stable cobalt(ii) complex, a mild reducing agent Zn and a simple proton source (H2O) are used. A radical mechanism for the addition of alkyl tosylates to activated alkenes is likely involved.
- Hsieh, Jen-Chieh,Chu, Yi-Hua,Muralirajan, Krishnamoorthy,Cheng, Chien-Hong
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supporting information
p. 11584 - 11587
(2017/10/27)
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- Copper-Catalyzed C-S Bond Formation via the Cleavage of C-O Bonds in the Presence of S8 as the Sulfur Source
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Useful and applicable methods for one-pot and odorless synthesis of unsymmetrical and symmetrical diaryl sulfides via C-O bond activation are presented. First, a new efficient procedure for the synthesis of unsymmetrical sulfides using the cross-coupling reaction of phenolic esters such as acetates, tosylates, and triflates and with arylboronic acid or triphenyltin chloride as the coupling partners is reported. Depending on the reaction, S 8 /KF or S 8 /NaO t -Bu system is found to be an effective source of sulfur in the presence of copper salts and in poly(ethylene glycol) as a green solvent. Then, the synthesis of symmetrical diaryl sulfides from phenolic compounds by using S 8 as the sulfur source and NaO t -Bu in anhydrous DMF at 120 °C under N 2 is described. By these protocols, the synthesis of a variety of unsymmetrical and symmetrical sulfides become easier than the available protocols in which thiols and aryl halides are directly used for the preparation of the sulfides.
- Rostami, Abed,Rostami, Amin,Ghaderi, Arash,Gholinejad, Mohammad,Gheisarzadeh, Sajedeh
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p. 5025 - 5038
(2017/10/06)
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- Copper-Catalyzed Regioselective C-H Sulfonyloxylation of Electron-Rich Arenes with p-Toluenesulfonic Acid and Sulfonyloxylation of Aryl(mesityl)iodonium Sulfonates
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Copper-catalyzed regioselective C-H sulfonyloxylation of electron-rich arenes with p-toluenesulfonic acid has been developed. Electron-rich benzene derivatives and heteroarenes can undergo this C-H sulfonyloxylation reaction to generate aryl tosylates. Furthermore, sulfonyloxylation of aryl(mesityl)iodonium sulfonates has also been investigated. Both aryl(mesityl)iodonium tosylates and triflates can react smoothly to get aryl sulfonates. The formed aryl sulfonates can be converted to phenols, as well as used as good partners of cross-coupling reactions.
- Huang, He,Wu, Yang,Zhang, Wen,Feng, Chun,Wang, Bi-Qin,Cai, Wan-Fei,Hu, Ping,Zhao, Ke-Qing,Xiang, Shi-Kai
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p. 3094 - 3101
(2017/03/23)
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- Syntheses of N-aryl-protected glucosamines and their stereoselectivity in chemical glycosylations
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N-Aryl-protecting groups were introduced in glucosamines to achieve β-selective glycosylation. Various N-aryl aminosugars were synthesized via Buchwald–Hartwig reaction. Glycosylation using glycosyl trichloroacetimidates of N-aryl aminosugars smoothly proceeded in the presence of trimethylsilyl trifluoromethanesulfonate. Use of a glycosyl donor comprising an electron-donating 2,4-dimethoxyphenyl (DMP) group led to the glycosylation proceeding with high β selectivity. This stereoselectivity seemed to be derived from the formation of an aziridine intermediate. The DMP-protecting group can be removed immediately by using ammonium hexanitratocerate (IV).
- Otsuka, Yuji,Yamamoto, Toshihiro,Fukase, Koichi
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supporting information
p. 3019 - 3023
(2017/07/17)
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- Nickel-Catalyzed Cyanation of Aryl Chlorides and Triflates Using Butyronitrile: Merging Retro-hydrocyanation with Cross-Coupling
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We describe a nickel-catalyzed cyanation reaction of aryl (pseudo)halides that employs butyronitrile as a cyanating reagent instead of highly toxic cyanide salts. A dual catalytic cycle merging retro-hydrocyanation and cross-coupling enables the conversion of a broad array of aryl chlorides and aryl/vinyl triflates into their corresponding nitriles. This new reaction provides a strategically distinct approach to the safe preparation of aryl cyanides, which are essential compounds in agrochemistry and medicinal chemistry.
- Yu, Peng,Morandi, Bill
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supporting information
p. 15693 - 15697
(2017/12/02)
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- A Nickel-Catalyzed Carbonyl-Heck Reaction
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The use of transition-metal catalysis to enable the coupling of readily available organic molecules has greatly enhanced the ability of chemists to access complex chemical structures. In this work, an intermolecular coupling reaction that unites organotriflates and aldehydes is presented. A unique catalyst system is identified to enable this reaction, featuring a Ni0 precatalyst, a tridentate Triphos ligand, and a bulky amine base. This transformation provides access to a variety of ketone-containing products without the selectivity- and reactivity-related challenges associated with more traditional Friedel–Crafts reactions. A Heck-type mechanism is postulated, wherein the π bond of the aldehyde takes the role of the olefin in the insertion/elimination steps.
- Vandavasi, Jaya Kishore,Hua, XiYe,Halima, Hamdi Ben,Newman, Stephen G.
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supporting information
p. 15441 - 15445
(2017/11/10)
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- Nickel-catalyzed phosphorylation of aryl triflates with P([Formula presented] compounds
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A nickel-catalyzed phosphorylation of aryl triflates with P([Formula presented] compounds is disclosed. This reaction can proceed smoothly under a mild reaction condition, producing the corresponding aryl phosphorus compounds in good to high yields.
- Yang, Jia,Xiao, Jing,Chen, Tieqiao,Han, Li-Biao
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p. 120 - 124
(2016/08/23)
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- Direct conversion of phosphonates to phosphine oxides: An improved synthetic route to phosphines including the first synthesis of methyl JohnPhos
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The synthesis of tertiary phosphine oxides from phosphonates was achieved reliably and in good to excellent yields using stoichiometric amounts of alkyl or aryl Grignard reagents and sodium trifluoromethanesulfonate (NaOTf). In the absence of the NaOTf additive, covalent coordination oligomers of magnesium and phosphorus species dominate the reaction, producing very low yields of phosphine oxide, but high conversions of the phosphonate starting material. Mechanistic studies revealed that a five-coordinate phosphorus species - not a phosphinate - is the reaction intermediate. A diverse array of phosphonates was converted to phosphine oxides using a variety of Grignard reagents for direct carbon-phosphorus functionalization. This new methodology especially simplifies the synthesis of dimethylphosphino (RPMe2)-type phosphines by using air-, water-, and silica-stable intermediates. To highlight this reaction, a new Buchwald-type ligand ([1,1′-biphenyl]-2-yldimethylphosphine, or methyl JohnPhos) and a classic bidentate phosphine, bis(diphenylphosphino)propane (dppp), were synthesized in excellent yields.
- Kendall, Alexander J.,Salazar, Chase A.,Martino, Patrick F.,Tyler, David R.
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supporting information
p. 6171 - 6178
(2015/02/19)
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- Highly active catalysts of bisphosphine oxides for asymmetric Heck reaction
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Bisphosphine oxides formed highly active asymmetric Heck catalysts, which were applied in asymmetric synthesis of pharmacologically active azacycles. Olefin insertion proceeded via cis pathways, different from P,N-ligands.
- Hu, Jian,Lu, Yunpeng,Li, Yongxin,Zhou, Jianrong
-
supporting information
p. 9425 - 9427
(2013/10/01)
-
- Selective arylation and vinylation at the α position of vinylarenes
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In intermolecular Heck reactions of styrene and vinylarenes, the aryl and vinyl groups routinely insert at the β position. However, selective insertion at the α position has been very rare. Herein, we provide a missing piece in the palette of Heck reaction, which gave >20:1 α selectivity. The key to our success is a new ferrocene 1,1′-bisphosphane (dnpf) that carries 1-naphthyl groups. Our mechanistic studies revealed that the high α selectivity is partly attributable to the steric effect of dnpf. The rigid and bulky 1-naphthyl groups of dnpf sterically disfavor β insertion. What the Heck! In intermolecular Heck reactions, insertion at the β position of aromatic olefins is very common, but reversal of the selectivity for selective α insertion has been a longstanding problem. A general method to couple aryl and vinyl triflates with aromatic olefins in >20:1 α selectivity is presented. The key to this successful approach is a new ferrocene bisphosphane with naphthyl groups on the phosphorus atom (see scheme; OTf=triflate). Copyright
- Zou, Yinjun,Qin, Liena,Ren, Xinfeng,Lu, Yunpeng,Li, Yongxin,Zhou, Jianrong
-
supporting information
p. 3504 - 3511
(2013/07/05)
-
- Achieving vinylic selectivity in Mizoroki-heck reaction of cyclic olefins
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In Heck reactions of cyclic olefins, the products usually have aryl groups that end up at the allylic and/or homoallylic position. We herein report new selectivity that adds aryl groups to the vinylic position. Cyclic olefins of various ring size worked well. The desired isomers were produced by palladium-hydride-catalyzed isomerization of the initial products. Thus, a specific catalyst must be used so that it can perform two jobs under one set of reaction conditions. Copyright
- Wu, Xiaojin,Lu, Yunpeng,Hirao, Hajime,Zhou, Jianrong
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supporting information
p. 6014 - 6020
(2013/06/26)
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- Copper-catalyzed trifluoromethylation of allylsilanes
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CF3 on Csp3: Trifluoromethylation of allylsilane derivatives was accomplished through the use of CuI and Togni's reagent (1) under mild conditions. The reaction of allylsilanes without a substituent in the 2-position gave vinylsilane derivative
- Shimizu, Ryo,Egami, Hiromichi,Hamashima, Yoshitaka,Sodeoka, Mikiko
-
supporting information; experimental part
p. 4577 - 4580
(2012/06/18)
-
- Intermolecular mizoroki-heck reaction of aliphatic olefins with high selectivity for substitution at the internal position
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New ligand for old reaction: The title reaction of aryltriflates with aliphatic olefins leads to substitution at the internal position with high selectivity. The ratio of the desired isomer (shown in the scheme) to the sum of all other isomers is generall
- Qin, Liena,Ren, Xinfeng,Lu, Yunpeng,Li, Yongxin,Zhou, Jianrong
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supporting information; experimental part
p. 5915 - 5919
(2012/07/30)
-
- Nickel-catalyzed C-H/C-O coupling of azoles with phenol derivatives
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The first nickel-catalyzed C-H bond arylation of azoles with phenol derivatives is described. The new Ni(cod)2/dcype catalytic system is active for the coupling of various phenol derivatives such as esters, carbamates, carbonates, sulfamates, triflates, tosylates, and mesylates. With this C-H/C-O biaryl coupling, we synthesized a series of privileged 2-arylazoles, including biologically active alkaloids. Moreover, we demonstrated the utility of the present reaction for functionalizing estrone and quinine.
- Muto, Kei,Yamaguchi, Junichiro,Itami, Kenichiro
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supporting information; experimental part
p. 169 - 172
(2012/03/07)
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- Palladium-catalyzed desulfitative arylation by C-O bond cleavage of aryl triflates with sodium arylsulfinates
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An efficient Pd-catalyzed desulfitative coupling reaction of sodium arylsulfinates as arylation reagents by C-O bond cleavage of aryl triflates was developed. With only 2 mol % of Pd(OAc)2 as catalyst and XPhos as ligand, the reaction proceeded well for a range of substrates.
- Zhou, Chao,Liu, Qingjiang,Li, Yaming,Zhang, Rong,Fu, Xinmei,Duan, Chunying
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p. 10468 - 10472
(2013/01/15)
-
- Suzuki-miyaura cross-coupling reactions in flow: Multistep synthesis enabled by a microfluidic extraction
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Continuous success: A continuous-flow Suzuki-Miyaura cross-coupling reaction starting from phenols was made possible through use of an efficient microfluidic extraction operation and a packed-bed reactor. Various biaryls were obtained in excellent yield (
- Noal, Timothy,Kuhn, Simon,Musacchio, Andrew J.,Jensen, Klavs F.,Buchwald, Stephen L.
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supporting information; experimental part
p. 5943 - 5946
(2011/08/02)
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- Biaryl and aryl ketone synthesis via Pd-catalyzed decarboxylase coupling of carboxylate salts with aryl triflates
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A bimetallic catalyst system has been developed that for the first time allows the decarboxylative crosscoupling of aryl and acyl carboxylates with aryl triflates. In contrast to aryl halides, these electrophiles give rise to non-coordinating anions as byproducts, which do not interfere with the decarboxylation step that leads to the generation of the carbon nucleophilic crosscoupling partner. As a result, the scope of carboxylate substrates usable in this transformation was extended from ortho-substituted or otherwise activated derivatives to a broad range of ortho-, meta-, and para-substituted aromatic carboxylates. Two alternative protocols have been optimized, one involving heating the substrates in the presence of CuI/1,10- phenanthroline (10-15 mol %) and PdI2/phosphine (23 mol%) in NMP for 1-24 h, the other involving CuI/l,10-phenanthroline (615mol%) and PdBr2/Tol-BINAP (2 mol % ) in NMP using microwave heating for 5-10 min. While most products are accessible using standard heating, the use of microwave irradiation was found to be beneficial especially for the conversion of non-activated carboxylates with functionalized aryl triflates. The synthetic utility of the transformation is demonstrated with 48 examples showing the scope and limitations of both protocols. In mechanistic studies, the special role of microwave irradiation is elucidated, and further perspectives of decarboxylase crosscouplings are discussed.
- Goossen, Lukas J.,Linder, Christophe,Rodriguez, Nuria,Lange, Paul P.
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supporting information; experimental part
p. 9336 - 9349
(2010/04/03)
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- Direct synthesis of primary arylamines via C-N cross-coupling of aryl bromides and triflates with amides
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Aryl halides and triflates are coupled with primary amides to give the corresponding arylamines in the presence of a palladium catalyst, a suitable ligand, and a base. The catalyst system performs well for a large number of different substrates at 100-150 °C without solvent, and with low catalyst levels (0.12 mol % Pd). Nicotinamide might be useful as a nitrogen source in the Pd-catalyzed amination reaction.
- Romero,Harrak,Basset,Orúe,Pujol
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experimental part
p. 1951 - 1956
(2009/07/11)
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- Generation and suppression of 3-/4-functionalized benzynes using zinc ate base (TMP-Zn-ate): New approaches to multisubstituted benzenes
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We present full details of our new methods for preparing functionalized benzynes with lithium di-alkyl(2,2,6,6-tetramethylpiperidino)zincate (R 2Zn(TMP)Li) through deprotonative zincation as a key reaction. In this system, by choosing appropriate ligands for the zincate, either regioselective zincation of functionalized haloaromatics or the generation of substituted benzynes can be controlled in good yields with excellent chemoselectivity, using the same substrate. Zincation with tBu 2Zn(TMP)Li followed by electrophilic trapping or zincation with Me2Zn(TMP)Li followed by nucleophilic or diene trapping is shown to be a powerful tool for the chemoselective preparation of 1,2,3-/1,2,4- trisubstituted benzene derivatives. These methods offer far greater generality than previous methods for the synthesis of multifunctionalized benzenes. Computational/theoretical studies of the reaction mechanism of this unique benzyne formation indicated that preferential coordination of the dialkylzinc moiety of zincate to halogen is the reason for the reduced activation energy of the elimination, that is, for the formation of the benzyne. The role of the ligands on Zn in accelerating/decelerating the elimination is also discussed.
- Uchiyama, Masanobu,Kobayashi, Yuri,Furuyama, Taniyuki,Nakamura, Shinji,Kajihara, Yumiko,Miyoshi, Tomoko,Sakamoto, Takao,Kondo, Yoshinori,Morokuma, Keiji
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p. 472 - 480
(2008/10/09)
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- Decarboxylative biaryl synthesis from aromatic carboxylates and aryl triflates
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A new catalyst system, generated in situ from Cu2O, 1,10-phenanthroline, PdI2, and Tol-BINAP, for the first time allows the decarboxylative coupling of carboxylic acids with aryl triflates. In contrast to previous decarboxylative couplings that remained limited to certain activated carboxylates, e.g., ortho-substituted benzoates, this halide-free protocol is generally applicable to aromatic carboxylic acid salts regardless of their substitution pattern. Copyright
- Goossen, Lukas J.,Rodriguez, Nuria,Linder, Christophe
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supporting information; experimental part
p. 15248 - 15249
(2009/03/11)
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- Aryl triflates: Useful coupling partners for the direct arylation of heteroaryl derivatives via Pd-catalyzed C-H activation-functionalization
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Aryl triflates were found to be suitable partners for the palladium catalyzed direct arylation of heteroaromatics via C-H activation- functionalization. The reaction conditions and the catalyst have a determining influence on the yields. The system combining PPh3 and Pd(OAc) 2 using KOAc as base and DMF as solvent promotes the selective 2- or 5-arylations in moderate to high yields. Several heteroaromatics such as furan, thiophene, thiazole or oxazole derivatives have been employed successfully. The electronic properties of the aryl triflates also have a decisive influence on the yields of the coupling products. Electron-rich aryl triflates gave satisfactory results, whereas the electron-poor ones led to the formation of phenols. The Royal Society of Chemistry 2008.
- Roger, Julien,Doucet, Henri
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p. 169 - 174
(2008/09/20)
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- Palladium-catalyzed reductive carbonylation of aryl triflates with synthesis gas
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A general palladium-catalyzed reductive carbonylation of aryl triflates in the presence of synthesis gas (CO/H2) has been developed. The reaction with this most simple and environmentally benign formylation source proceeds under mild conditions and various aromatic aldehydes have been prepared in good to high yield. Georg Thieme Verlag Stuttgart.
- Brennfuhrer, Anne,Neumann, Helfried,Beller, Matthias
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p. 2537 - 2540
(2008/02/13)
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- Heterogeneous Pd/C-catalyzed ligand-free, room-temperature suzuki-miyaura coupling reactions in aqueous media
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A mild and efficient ligand-free Suzuki-Miyaura coupling reaction catalyzed by heterogeneous Pd/C was developed. Aryl bromides and triflates undergo the cross-coupling with aryl boronic acids in excellent yields without the presence of any additives in aqueous media at room temperature. Aryl vinyl boronic acids are also applicable to this coupling reaction and provide the trans-stilbene derivatives in high yields. The application of wet-type Pd/C to the coupling reaction was achieved without any loss of activity under aerobic conditions, and the reuse of Pd/C is feasible for a fifth run without significant loss of activity. Inductively coupled plasma (ICP) mass-spectrometric analysis of the filtrate from the reaction mixture of 4-bromonitrobenzene with phenylboronic acid demonstrated that the palladium metal hardly leached into the solution within the limits of the detector ( 1 ppm), thus suggesting that the present Suzuki-Miyaura reaction proceeded by heterogeneous catalysis.
- Maegawa, Tomohiro,Kitamura, Yoshiaki,Sako, Satoko,Udzu, Takahiro,Sakurai, Ai,Tanaka, Asami,Kobayashi, Yusuke,Endo, Koichi,Bora, Utpal,Kurita, Takanori,Kozaki, Atsushi,Monguchi, Yasunari,Sajiki, Hironao
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p. 5937 - 5943
(2008/02/13)
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- The conversion of phenols to the corresponding aryl halides under mild conditions
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Mild, novel procedures have been developed for the syntheses of aryl halides from the corresponding phenols in modest to good yields via boronate ester intermediates.
- Thompson, Alicia L. S.,Kabalka, George W.,Akula, Murthy R.,Huffman, John W.
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p. 547 - 550
(2007/10/03)
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- 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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- Palladium-catalyzed phosphination of functionalized aryl triflates
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Catalytic user-friendly approach to the syntheses of various functionalized aromatic phosphines from their corresponding substituted aryl triflates and triarylphosphines was accomplished. This method is carried out in neutral media and compatible with man
- Kwong, Fuk Yee,Lai, Chi Wai,Yu, Michael,Tian, Yuan,Chan, Kin Shing
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p. 10295 - 10305
(2007/10/03)
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- Fast Synthesis of Aryl Triflates with Controlled Microwave Heating
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matrix presented Synthesis of aryl triflates from phenols using N-phenyltriflimide requires only 6 min for completion when conducted with controlled microwave heating. The methodology was applied to both solution- and solid-phase conditions. Ten different
- Bengtson, Anna,Hallberg, Anders,Larhed, Mats
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p. 1231 - 1233
(2007/10/03)
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- Practical Synthesis of Aryl Triflates under Aqueous Conditions
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A practical and efficient synthesis of aryl triflates under biphasic basic aqueous conditions is described. The current methodology provides entry into these valuable substrates that omits the use of amine bases and allows facile isolation by s
- Frantz, Doug E.,Weaver, Damian G.,Carey, James P.,Kress, Michael H.,Dolling, Ulf H.
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p. 4717 - 4718
(2007/10/03)
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- A soluble polymer-supported triflating reagent: a high-throughput synthetic approach to aryl and enol triflates.
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[reaction: see text] The high-yielding synthesis and application of the first example of a polymer-supported reagent for the preparation of trifluoromethanesulfonates (triflates) is described. This new reagent efficiently triflates aryl alcohols and lithi
- Wentworth,Wentworth Jr.,Mansoor,Janda
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p. 477 - 480
(2007/10/03)
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- A high throughput synthesis of aryl triflate and aryl nonaflate promoted by a polymer supported base (PTBD)
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A rapid synthesis of aryl triflate and aryl nonaflate was developed using 4-nitrophenyl triflate and 4-nitrophenyl nonaflate as perfluoroalkanesulfonyl transfer reagents in combination with a polymer supported base (PTBD). Simple filtration of the reactio
- Boisnard, Sabine,Chastanet, Jaqueline,Zhu, Jieping
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p. 7469 - 7472
(2007/10/03)
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