排序方式: 共有28条查询结果,搜索用时 46 毫秒
1.
Adyl Bernard Bernard Garrigues 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):825-832
In presence of bismuth(III) triflate, a carbonylated electrophile (ethyl mesoxalate or glyoxylate) and usual diene led selectively (60-100) the hetero carbonyl-Diels-Alder reaction with the ene reaction product. Bi(OTf) 3 exhibits strong catalytic activity and reacts under mild conditions. En présence de triflate de bismuth(III) le mésoxalate et le glyoxylate d'éthyle réagissent avec des diènes usuels pour donner un mélange de carbonyl-Diels-Alder et du produit de la ène réaction. Bi(OTf) 3 présente une forte activité catalytique et réagit dans des conditions douces. 相似文献
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Les Sels de Bismuth (III) Comme Catalyseurs Dans la Reaction D'ouverture Des Epoxydes Par Les Amines
Adyl Oussaid Bernard Garrigues Boualem Oussaid Fatima Benyaquad 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2315-2320
BiCl 3 and Bi (OTf) 3 catalyze the opening of epoxides ( 1-7 ) by amines ( 8-12 ). High regioselectivities are observed. BiCl 3 et Bi (OTf) 3 catalysent la réaction d'ouverture des époxydes ( 1-7 ) par les amines ( 8-12 ). La réaction est fortement régiosélective. 相似文献
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Sophie R. Beeren 《Journal of organometallic chemistry》2009,694(2):309-2207
A series of silver complexes generated in situ from AgOSO2CF3 (AgOTf) and a range of bidentate ligands were investigated as catalysts for the intramolecular hydroamination of 4-pentyn-1-amine. A variety of P- and N-donor ligands were tested including the novel pyrazole-phosphine ligand 1-(2-(diphenylphosphino)phenyl)pyrazole. The best catalyst was formed from equimolar amounts of the P,N-donor ligand 1-(2-(diphenylphosphino)ethyl)pyrazole and AgOTf, which achieved a turnover rate of 129 h−1 for the cyclisation of 4-pentyn-1-amine. 相似文献
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Yuning Liu 《高分子科学杂志,A辑:纯化学与应用化学》2017,54(10):678-683
Triflate Ester of Calix[n]arene (n = 4, 6, 8) (TEC[n] (n = 4, 6, 8)) were synthesized based on a new synthetic route, then TEC[n] (n = 4, 6, 8) were further modified by reacting with low molecular weight Chitosan (CS) to get three kinds of new Calix[n]arene-Chitosan polymers (n = 4, 6, 8) (C[n]CSP (n = 4, 6, 8)) through Buchwald-Hartwig cross coupling reaction. The structures of the polymers were characterized by FT-IR, SEM, Elemental analyzer and 13C SSNMR. And the results found that Chitosan was successfully introduced to Calix[n]arene (n = 4, 6, 8) (C[n] (n = 4, 6, 8)) without any long-chain alkyl between Chitosan and Calixarene. These new polymers are partially substituted calixarene. The substitute degree of C[4]CSP, C[6]CSP and C[8]CSP is 17.75%, 21.08% and 54.53% respectively. And the optimal preparation conditions were discussed and the results were listed as following, molar ratio (1:2), catalyst (0.05 mmol), solvent ratio (1:1.5 (10 mL?1.0 mmol?1)) and reaction time (5h). 相似文献
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Synthesis of bis(polyfluoroalkylated)imidazolium salts as key intermediates for fluorous NHC ligands
Martin Skalický Ond?ej Kysilka Josef Cva?ka Jaroslav Kví?ala 《Journal of fluorine chemistry》2009,130(10):966-10297
1,3-Bis(polyfluoroalkyl)- and 1-mesityl-3-(polyfluoroalkyl)imidazolium salts differing in the length of a polyfluorinated chain and a non-fluorinated spacer were synthesized as key building blocks for fluorous NHC (N-heterocyclic carbene) ligands. A new approach using polyfluoroalkyl triflates instead of the corresponding iodides was employed allowing fine tailoring of fluorous properties, as well as of the electron density of the imidazolium ring. Using bis(polyfluoroalkylated)imidazolium salt, a fluorous analogue of the PEPPSI™ catalyst was synthesized and its structure confirmed by X-ray diffraction. The catalyst was employed in model Heck and Suzuki couplings with moderate yields, however, its recycle was not successful. Fluorophilicity of bis(polyfluoroalkylated)imidazolium salts was found to be surprisingly low compared with the analogous perfluoropolyether-based salts. 相似文献
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Thermolysis of Ni(OTf)2 in 2-phenyl-pyridine or 2-tolyl-pyridine afforded the cationic chelate derivatives, [bis(2-aryl-pyridine)Ni{(2-aryl-κC2)pyridine-κN}]OTf (aryl = phenyl, 1a; tolyl, 1b). Addition of KBr to 1a and LiBr to 1b provided the bromides, (2-aryl-pyridine)BrNi{(2-aryl-κC2)pyridine-κN} (aryl = phenyl, 2a; tolyl, 2b). When subjected to KOtBu in Et2O, the bromides generated the entitled bis-cyclometalated compounds, Ni{(2-aryl-κC2)pyridine-κN}2 (aryl = phenyl, 3a; tolyl, 3b). These compounds insert diphenylacetylene into one cyclometalate arm to produce [(2-aryl-κC2)pyridine-κN]Ni[2-(2-(1,2-diphenylethenyl-κC2)aryl)pyridine-κN] (aryl = phenyl, 4a; p-tolyl, 4b). X-ray crystallographic studies were conducted on 1a, 2a, 3a and 4a, and a brief DFT study of 3a confirmed its low spin configuration and rippled geometry. 相似文献
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Jeroen D.C Codée Remy E.J.N Litjens Constant A.A van Boeckel Gijs A van der Marel 《Tetrahedron》2004,60(5):1057-1064
A novel chemoselective glycosylation sequence is described that employs the recently developed BSP/Tf2O and DPS/Tf2O reagent systems to activate thioglycosides. In the first glycosylation event a relatively armed thioglycoside is activated with the BSP/Tf2O activator system and condensed with an acceptor thioglycoside to yield the thiodisaccharide, which is activated with the more potent DPS/Tf2O activator in the next glycosylation event. Quenching of (N-piperidino)phenyl(S-thiophenyl)sulfide triflate, which is formed upon activation of the first thioglycoside, with triethyl phosphite is crucial for a productive glycosylation. 相似文献