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1.
[reaction: see text] N-Alkyl- and N-arylanilines were synthesized from arenes by a two-step sequence of iridium-catalyzed borylation and copper-catalyzed coupling with amines. Diaryl ethers were obtained by a related sequence of arene borylation, followed by coupling with phenols. In particular, 3,5-disubstituted arylamines and aryl ethers were prepared by initiating this sequence with meta-substituted arenes. 相似文献
2.
M Pérez M Fañanás-Mastral V Hornillos A Rudolph PH Bos SR Harutyunyan BL Feringa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(38):11880-11883
A highly efficient, regio- and enantioselective Cu(I) /phosphoramidite-catalyzed asymmetric allylic alkylation of allyl ethers with organolithium reagents is reported. The use of organolithium reagents is essential for this catalytic C?C bond formation due to their compatibility with different Lewis acids. The versatility of allylic ethers under the copper-catalyzed reaction conditions with organolithium reagents is demonstrated in the shortest synthesis of (S)-Arundic acid. 相似文献
3.
《Tetrahedron letters》2019,60(31):2084-2087
A novel copper-catalyzed amination of ethers using isocyanates and DTBP is developed. The reaction provides a unique approach to the synthesis of Boc-protected α-aminals through three-component radical cascade reactions. It provides an alternative method for the construction of this type of valuable motifs in high yield. Meanwhile, the method exhibits high tolerance of various functional groups, such as ether, halide, ester and acyl functionalities. 相似文献
4.
A series of salicylaldimine ligands were designed to promote the copper-catalyzed Ullmann cross- coupling reaction. After a screening process, 2-((2-isopropylphenylimino)methyl)phenol was found to serve as a good supporting ligand for this reaction. Employing this Schiff-base ligand as a new supporting ligand, the copper-catalyzed coupling reactions of aryl bromides and aryl iodides with various phenols successfully proceeded in good yields under mild conditions. Various diaryl ethers were obtained with excellent yields in dioxane in the presence of K3P04 and a catalytic amount of copper(I) salt. 相似文献
5.
Tong Zhang Xing-Wang Lan Yu-Qiang Zhou Nai-Xing Wang Yue-Hua Wu Yalan Xing Jia-Long Wen 《中国科学:化学(英文版)》2018,61(2):180-183
A copper-catalyzed decarboxylative oxidative coupling of α,β-unsaturated carboxylic acids with non-cyclic ethers is developed. This method provides a new approach for C(sp3)–H bond functionalization of non-cyclic ethers. Mechanism study shows the reaction involves a radical process. 相似文献
6.
Zhu SF Song XG Li Y Cai Y Zhou QL 《Journal of the American Chemical Society》2010,132(46):16374-16376
A copper-catalyzed asymmetric intramolecular O-H insertion of ω-hydroxy-α-diazoesters has been accomplished by using chiral spiro bisoxazoline ligands. This highly enantioselective intramolecular O-H insertion reaction provides an efficient approach to a variety of synthetically important chiral 2-carboxy cyclic ethers with different ring sizes as well as substitution patterns. 相似文献
7.
A copper-catalyzed dehydrogenative cross-coupling reaction between unactivated ethers and simple ketones mediated by pyrrolidine has been developed. Under the catalysis of CuBr2 and in the presence of pyrrolidine, either tetrahydrofuran 2a or tetrahydropyran 2b can react smoothly with a series of methyl aryl ketones 1a–m to give desired coupling products 3aa–mb using TBHP as an oxidant. The advantages of the dehydrogenative cross-coupling reaction are adoption of unmodified ethers as substrates, good tolerance of many functional groups and use of cheap copper salt as a catalyst. A plausible radical mechanism through enamine attack is proposed. 相似文献
8.
Alza E Sayalero S Kasaplar P Almaşi D Pericàs MA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(41):11585-11595
α,α-Diphenylprolinol methyl- and trimethylsilyl ethers anchored onto a polystyrene resin have been prepared by a copper-catalyzed azide-alkyne cycloadditions (CuAAC). The catalytic activity and enantioselectivity displayed by the O-trimethylsilyl derivative are comparable to those exhibited by the best known homogeneous catalysts for the addition of aldehydes to nitroolefins and of malonates or nitromethane to α,β-unsaturated aldehydes. The combination of the catalytic unit, the triazole linker, and the polymeric matrix provides unprecedented substrate selectivity, in favor of linear, short-chain aldehydes, when the organocatalyzed reaction proceeds by an enamine mechanism. High versatility is noted in reactions that proceed via an iminium ion intermediate. The catalytic behavior of polystyrene-supported α,α-diphenylprolinol methyl ether was also evaluated in asymmetric Michael addition reactions. As a general trend, the CuAAC immobilization of diarylprolinol ethers onto insoluble polystyrene resins offers important operational advantages, such as high catalytic activity, easy recovery from the reaction mixture by simple filtration, and the possibility of extended reuse. 相似文献
9.
Simin Maleknia Chien-Chung Liou Jennifer Brodbelt 《Journal of mass spectrometry : JMS》1991,26(11):997-1002
The collision-activated dissociation (CAD) mass spectra for a series of crown ethers, perfluoro crown ethers, cryptands and several dicyclohexano substituted crown ethers are reported. The CAD spectra were acquired with a triple quadrupole mass spectrometer, and in some cases spectra were recorded as a function of collision energy. In general, the protonated crown ethers dissociate via a series of losses of C2H4O units. The perfluoro crown ethers dissociate predominantly via losses of C2F4O units. The dicyclohexano ethers fragment in analogous ways in conjunction with cleavage of the cyclohexano rings. CAD spectra are also reported for acyclic ether systems. 相似文献
10.
《Tetrahedron letters》1989,30(2):239-242
Silyl enol ethers (2) react with tributyl [(phenylthio) chloromethyl] stannane (1) in the presence of Zinc bromide to give β-phenylthiomethylstannyl ketones (3) in good yields. Silyl dienol ethers (4) mainly give products (5) due to γ-attack, under these conditions. 相似文献
11.
8-Hydroxyquinolin-N-oxide was found to be a very efficient ligand for the copper-catalyzed hydroxylation of aryl iodides, aryl bromides, or aryl chlorides under mild reaction conditions. This methodology provides a direct transformation of aryl halides to phenols and to alkyl aryl ethers. The inexpensive catalytic system showed great functional group tolerance and excellent selectivity. 相似文献
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13.
Employing ethyl 2-oxocyclohexanecarboxylate as a novel, efficient, and versatile ligand, the copper-catalyzed coupling reactions of various N/O/S nucleophilic reagents with aryl halides could be successfully carried out under mild conditions. A variety of products including N-arylamides, N-arylimidazoles, aryl ethers, and aryl thioethers were synthesized in good to excellent yields. 相似文献
14.
The reactions between alkali metal ions and crown ethers, aza crown ethers, and cryptands in propylene carbonate were studied by potentiometric and calorimetric titrations. The most stable complexes formed by macrocyclic and macrobicyclic ligands are when the ligand and cation dimensions are comparable. On comparing the complex stabilities of crown ethers and aza crown ethers of the same size, crown ethers were, on the whole, found to form the most stable complexes, with the exception of the lithium cation. Enthalpic factors are responsible. Substitution of the amino group protons of the aza crown ethers by benzyl groups leads to a high increase in values of the reaction enthalpy. This effect is partly compensated by entropic contributions. The bulky benzyl groups reduce the ligand solvent interactions and induce a ligand conformation with the lone pair of electrons from the nitrogen donor atoms which are more or less directed inside the cavity. The thermodynamic data for the transfer from methanol to propylene carbonate indicate that the ligands containing nitrogen show specific interactions with methanol.This paper is dedicated to Professor H. Strehlow on the occasion of his 70th birthday. 相似文献
15.
Gromov S. P. Dmitrieva S. N. Vedernikov A. I. Churakova M. V. 《Russian Chemical Bulletin》2004,53(7):1417-1427
The review summarizes the results of studies aimed at constructing new promising macrocyclic ligands that bind metal and ammonium ions. A new approach to the synthesis of formyl and nitro derivatives of 1-aza-2,3-benzocrown ethers possessing considerable synthetic potential is described. The review presents a radically new methodology for the synthesis of such benzoazacrown ethers based on stepwise transformations of the macrocycle of readily accessible benzocrown ethers. The main structural factors and necessary conditions enabling stepwise transformations of the macrocycle of crown ethers into azacrown ethers were revealed. For the first time, the ability of N-methylbenzoazacrown ethers to form complexes was found, which is much superior to that of widely used N-phenylazacrown ethers and benzocrown ethers with the same size of the macrocycle. 相似文献
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17.
Diphenyldisulfone is a mild and efficient reagent for selective cleavage of methylprenyl (2,3-dimethylbut-2-en-1-yl), prenyl (3-methylbut-2-en1-yl), and methallyl (2-methylallyl) ethers. These reaction conditions are compatible with the presence of other protecting groups such as acetals, acetates, and allyl, benzyl, and TBDMS ethers. Exposure of 2,3-dimethylbut-2-en-1-yl and 3-methylbut-2-en1-yl ethers to diphenyldisulfone led to the formation of 2,3-dimethylbuta-1,3-diene and isoprene, respectively. 2-Methylallyl ethers undergo isomerization to 2-methylpropenyl ethers, which are easily hydrolyzed into the corresponding free alcohols and isobutyraldehyde. [reaction: see text] 相似文献
18.
Unique structures of novel ionophores of double-armed penta-crown ethers were successfully synthesized. Diaza 18-crown-6 was designed as the parent crown ring. The penta-crown ethers were prepared by the reaction of trimethylolpropane triacrylate (TMPTA) with diaza 18-crown-6 and further with 1-aza crown ethers through the Michael reaction. The newly synthesized penta-crown ethers were characterized by 1H NMR, 13C NMR, FAB mass spectrum, IR and elemental analyses, respectively. 相似文献
19.
[reaction: see text] A simple procedure for the cleavage of triethylsilyl (TES) ethers in the presence of 10 wt % Pd/C in methanol or 95% ethanol is reported. This method allows selective removal of alkyl TES ethers in the presence of aromatic TES ethers or tert-butyldimethylsilyl (TBS) protecting groups. 相似文献
20.