共查询到20条相似文献,搜索用时 15 毫秒
1.
Shuaijun Han Apeng Liang Xiaoxiao Ren Xianying Gao Jingya Li Dapeng Zou Yangjie Wu Yusheng Wu 《Tetrahedron letters》2017,58(52):4859-4863
A simple protocol for the copper/B2pin2-catalyzed CH ethoxycarbonyldifluoromethylation of 8-aminoquinoline scaffolds with functionalized difluoromethyl bromides and iodines was developed, affording the desired products in moderate to good yields. This reaction was carried out under mild conditions and features good substrate tolerance. 相似文献
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3.
Tatsuo Ishiyama Jun Takagi Akihiro Kamon Norio Miyaura 《Journal of organometallic chemistry》2003,687(2):284-290
Cross-coupling reaction of bis(pinacolato)diboron with β-(trifluoromethanesulfonyloxy)-α,β-unsaturated carbonyl compounds was carried out in the presence of PdCl2(PPh3)2-2PPh3 (3 mol%) and KOPh in toluene or K2CO3 in dioxane for the synthesis of cyclic and acyclic β-boryl-α,β-unsaturated esters, amides, and ketones in high yields. The vinylboronates thus obtained readily participated in carboncarbon bond formation such as cross-coupling with vinyl triflates and 1,4-addition to α,β-unsaturated ketones. 相似文献
4.
Copper boryl reagents enable the selective cleavage of aryl allyl ethers to the corresponding phenols in good to moderate yields. 相似文献
5.
A novel and efficient method for the synthesis of gem-difluoroallylboronates via copper-catalyzed defluorinative borylation of α-trifluoromethyl alkenes with B2pin2 using Xantphos as ligand and NaOtBu as base was developed. 相似文献
6.
Ning Ma 《Tetrahedron》2007,63(22):4625-4629
The cyclopalladated ferrocenylimine was an efficient catalyst for the borylation/Suzuki coupling reaction. The catalytic loading for the reaction containing bromoarenes was 1 mol %. When iodobenzene was used, the catalytic loading was as low as 0.1 mol %. Furthermore, the cyclopalladated ferrocenylimine also exhibited excellent catalytic power in the case of substrates containing electron-donating substituents, with yields reaching 93% or higher. 相似文献
7.
A new protocol has been developed for the synthesis of arylboronates by a coupling reaction of aryl halides and bis(pinacolato)diboron using bis(triphenylphosphine)palladium dichloride/sodium acetate/polyethylene glycol 600 [Pd(PPh3)2Cl2/NaOAc/PEG 600] as an efficient catalytic system. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
8.
Since 1999, direct borylation of hydrocarbons catalyzed by a transition metal complex has been extensively studied by several groups and has become an economical, efficient, elegant, and environmentally benign protocol for the synthesis of a variety of organoboron compounds. Re-, Rh-, Ir- and Pd-catalyzed C---H borylation of alkanes, arenes and benzylic positions of alkylarenes by bis(pinacolato)diboron or pinacolborane provide alkyl-, aryl-, heteroaryl- and benzylboron compounds, respectively. In this review, seminal early works and exciting recent developments in the area of direct borylation of hydrocarbons via C---H activation are summarized. 相似文献
9.
A solution of bis(pentafluorophenyl)borane-dimethyl sulfide complex in hexane was generated by redistribution between tris(pentafluorophenyl)borane and borane-dimethyl sulfide complex. In the resulting solution a stoichiometric hydroboration of alk-1-yne with pinacolborane proceeded well at room temperature to afford (E)-alk-1-enylboronic acid pinacol ester in high yield. Bis(pentafluorophenyl)borane-dimethyl sulfide complex served as a mediator for the hydroboration. 相似文献
10.
Cis-alkenes are ubiquitous in biological molecules, which makes it greatly significant to develop efficient methods toward construction of cis-olefins. Herein, we reported a facile semi-hydrogenation of alkynes to cis-alkenes in an efficient way with cuprous bromide/tributylphosphine as the catalyst and bis(pinacolato)diboron/methanol as the hydrogen donor. The method features convenient and facile reaction conditions, wide substrate scope, high yields, and high stereoselectivity. 相似文献
11.
Jens Beckmann Dainis Dakternieks Susan L Floate Carl H Schiesser 《Journal of organometallic chemistry》2004,689(5):909-916
The H2PtCl6 catalysed hydrosilylation of the terpenes (+)-α-fenchene (XI), (−)-2-methylene bornane (XII), (+)-camphene (XIII) and (−)-3-methylene fenchane (XIV) using HSiMe2Cl or HSiMeCl2 proceeds with high regioselectively and in some cases, with high diastereoselectivity. KF-assisted oxidation of the hydrosilylation products gives predominately endo-terpene alcohols. The alcohols have inverted endo/exo ratios to those formed by oxidative hydroboration. Reaction of XIV with HSiMe2Cl or HSiMeCl2 is accompanied by a clean rearrangement of the isocamphane skeleton into (+)-2-methylene bornane (XII) prior to hydrosilylation. 相似文献
12.
5-Bromopyrimidines are converted to 5-hydroxypyrimidines using a mild synthetic procedure. The method is general and can be applied to compounds containing functional groups which are not compatible with the other reagents previously available for this conversion. 相似文献
13.
《Tetrahedron letters》2019,60(41):151086
Reactions of allyl-functionalized poly(ethylene glycol) (PEG) derivatives with alkoxysilanes proceeded efficiently to furnish the corresponding hydrosilylated products in good to excellent yields using a ruthenium catalyst, [RuCl2(nbd)]n. A preliminary mechanistic study supported the pivotal role of the PEG moiety, which coordinated to the ruthenium atom during the reaction to achieve high reaction selectivity. This method may be applicable to the synthesis of various PEGs with a silyl terminus, which is useful as biocompatible and low toxic silane coupling agents. 相似文献
14.
Xiaoling Yang Jiayun Li Yu Liu Jiajian Peng Tianbo Li 《Phosphorus, sulfur, and silicon and the related elements》2019,194(1-2):83-86
The catalytic activities of titanium alkoxides and alkali metal alkoxides for hydrosilylation of unfunctionalized olefins have been studied. Titanium(IV) alkoxides showed excellent catalytic activity, while alkali metal alkoxides have low catalytic activity for the hydrosilylation of olefins. However, by using titanocene dichloride as an additive, alkali metal alkoxides showed also excellent catalytic property for hydrosilylation. In comparison with titanium alkoxides, no α-adduct was obtained by using alkali metal alkoxides/Cp2TiCl2 as catalysts. 相似文献
15.
Zhenping Shang 《European Polymer Journal》2007,43(5):2135-2140
A one-pot synthesis method for the preparation of polyimides containing biphenyl units was developed via nickel-catalyzed coupling reaction of bis(chlorophthalimide)s which were prepared from chlorophthalic anhydrides and diamines in xylene. The resulting polyimides had inherent viscosities of above 0.60 dL g−1. In the meantime, the copolymerizations from a mixture of three isomeric bis(chlorophthalimide)s gave the polymers with inherent viscosities of 0.36-0.55 g dL−1. The solubility and film formability of the copolymers were better than those of homopolymers from bis(4-chlorophthalimide). The 10% weight loss of these polyimides was between 470 and 531 °C. 相似文献
16.
<正>A highly efficient and regio-/stereoselective method of hydrosilylating terminal alkynes was developed using Pt(DVDS)-tri(t-butyl) phosphine catalyst system at room temperature.Trans-products or alpha-products were obtained almost exclusively depending on the alkynes and silanes employed. 相似文献
17.
A novel fumed silica-supported nitrogenous platinum complex was conveniently prepared from cheap γ-aminopropyltriethoxysilane via immobilization on fumed silica in toluene, followed by a reaction with hexachloroplatinic acid. The title complex was characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It was found that the complex is an efficient and stable catalyst for the hydrosilylation of olefins with triethoxysilane. The title platinum complex could be separated by simple filtration and reused several times without any appreciable loss in the catalytic activity. 相似文献
18.
Claudia S. Straubinger Manuel P. Högerl Wolfgang A. Herrmann Fritz E. Kühn 《Journal of organometallic chemistry》2011,696(3):687-692
A series of chelating bridge functionalized bis-N-heterocyclic carbenes (NHC) complexes of rhodium (I) were prepared by reacting the corresponding imidazolium salts with [Rh(COD)Cl]2 in an in-situ reaction. For the N-methyl substituted complex with a PF6-anion an X-ray crystal structure was exemplary obtained. All complexes were spectroscopically characterized and tested for the hydrosilylation of acetophenone. 相似文献
19.
Xiaoling Yang Jiayun Li Yu Liu Tianbo Li 《Phosphorus, sulfur, and silicon and the related elements》2019,194(1-2):64-68
Hydrosilylation of olefins catalyzed by Cp2TiCl2/Sm (Cp?=?cyclopentadienyl) under solvent free conditions have been investigated. By using Cp2TiCl2/Sm as catalyst system, β-adducts and hydrogenation products were detected. Hydrosilylation of olefins catalyzed by Cp2TiCl2/LiAlH4 under room temperature has also been studied. The influence of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) on Cp2TiCl2/Sm and Cp2TiCl2/LiAlH4, respectively, indicated that hydrosilylation of olefins catalyzed with Cp2TiCl2/Sm went through a free radical reaction pathway while a coordination mechanism was applied for Cp2TiCl2/LiAlH4 catalyst system. 相似文献
20.
Dong-won Lee 《Tetrahedron letters》2004,45(28):5415-5417
Air and moisture stable copper(II) salts can be used to catalyze the hydrosilylation of aromatic ketones. The combination of catalytic amounts of copper(II) acetate or copper(II) acetate monohydrate (Cu(OAc)2·H2O) and BINAP in the presence of organosilanes as the stoichiometric reducing agent generates an active catalyst for the reduction of ketones. 相似文献