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1.
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. 相似文献
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Phosphites were employed as ligands in palladium-catalyzed Hiyama coupling reactions. The optimized reaction conditions were equimolar amounts (5 mol % each) of Pd(acac)2 and phosphite 1 in p-xylene at 80 °C with TBAF as an additive. This catalyst system exhibited high activities in the reactions with trimethoxysilylbenzene and aryl bromides that have electron-donating or electron-withdrawing groups. In the case of aryl chlorides, substrates possessing electron-withdrawing groups gave the coupled products in high yields. 相似文献
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[reaction: see text] Stereospecific cyclopropanation of alkenylboronic esters of pinacol followed by in situ treatment with excess KHF(2) afforded the corresponding potassium cyclopropyl trifluoroborates in high yields, which then underwent Suzuki-Miyaura cross-coupling reactions with aryl bromides to give cyclopropyl-substituted arenes in good yields with retention of configuration. This promises to be a useful method for the synthesis of enantiomerically pure cyclopropanes. 相似文献
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The palladium-catalyzed selective β-carboelimination and cross-coupling chemistry of benzocyclobutenols is described. In contrast to the base-mediated ring-opening reactions of benzocyclobutenols, this variant proceeds with exclusive cleavage of the proximal bond. 相似文献
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Yuusaku Yokoyama Sadao Ito Yumi Takahashi Yasuoki Murakami 《Tetrahedron letters》1985,26(52):6457-6460
Various aryl bromides underwent a palladium-catalyzed cross-coupling reaction with allyl acetate in the presence of hexa-n-butylditin to give the allylated products in very high yields. 相似文献
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[reaction: see text] Sodium silanolates derived from a number of heterocyclic silanols undergo cross-coupling with a variety of aromatic iodides and bromides under mild conditions. In situ deprotonation of the silanols with an equivalent amount of sodium hydride in toluene generates the sodium salt that couples with iodides under the action of Pd(2)(dba)(3).CHCl(3) in good yield at room temperature to 50 degrees C. The aromatic bromides also couple with these salts under the action of the Pd(I) catalyst 12. 相似文献
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[reaction: see text] A general method for the conversion of pyrrole anions to 2-arylpyrroles has been developed. Using a palladium precatalyst and sterically demanding 2-(dialkylphosphino)biphenyl ligands, (pyrrolyl)zinc chloride may be cross-coupled with a wide range of aryl halides, including aryl chlorides and aryl bromides, at low catalyst loadings and under mild conditions. A high degree of steric hindrance is tolerated. Certain ring-substituted pyrrole anions have also been arylated with aryl bromide substrates. 相似文献
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Shengqiang Wang Hongtao Lu Jingya Li Dapeng Zou Yusheng Wu Yangjie Wu 《Tetrahedron letters》2017,58(28):2723-2726
A straightforward method for the synthesis of functionalized 4- or 5-(hetero)arylpyrimidines via decarboxylative cross-coupling reaction from readily available pyrimidine-4- and pyrimidine-5-carboxylates was described. In the presence of dual-catalyst system of Pd(PPh3)4/Cu2O, the reaction proceeds smoothly, tolerates a variety of functional groups, and provides easy access to the synthesis of different (hetero)arylpyrimidines compounds. 相似文献
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[reaction: see text] (2-Pyridyl)allyldimethylsilanes were found to be novel pyridyl transfer reagents in palladium-catalyzed cross-coupling reactions of various aryl iodides in the presence of silver(I) oxide as an activator. 相似文献
12.
Various N-arylated sulfoximines have been synthesized in high yield by a direct approach which is based on a palladium-catalyzed cross-coupling strategy. Aryl bromides of variable substitution pattern were found to be the most effective coupling partners, whereas aryl iodides showed a nonpredictable behavior requiring lithium or silver salts as additives to ensure product formation in acceptable yields. Coupling of (S)-2-(2'-bromophenyl)-4-tert-butyloxazoline with enantiomerically pure (-)-(RS)-S-methyl-S-phenylsulfoximine afforded the corresponding product in good yield as a single diastereomer, showing that the palladium-catalyzed arylation proceeds in a stereospecific manner. The reaction with dibromobenzenes yielded the monosulfonimidoyl arenes in all cases, suggesting that the introduction of the sulfonimidoyl moiety deactivates the arene, thus preventing a second coupling step. 相似文献
13.
Palladium-catalyzed cross-coupling reaction of alkenyl bromides with potassium alkyltrifluoroborates
The Suzuki-Miyaura-type cross-coupling reaction of potassium alkyltrifluoroborates with various alkenyl bromides in the presence of 10 mol % of PdCl2(dppf)·CH2Cl2 and 3.0 equiv of Cs2CO3 in aqueous toluene at 80 °C provided the desired compounds in 63-95% yields. A variety of functional groups in the potassium alkyltrifluoroborates were tolerated under the basic conditions. 相似文献
14.
Aya YokoojiToru Okazawa Tetsuya SatohMasahiro Miura Masakatsu Nomura 《Tetrahedron》2003,59(30):5685-5689
Thiazole, 2-phenyl or -alkyl substituted one and benzothiazole are efficiently arylated with aryl bromides at the 2- and/or 5-position(s) in the presence of Pd(OAc)2 and a bulky phosphine ligand using Cs2CO3 as base. 2-Phenyl-5-thiazolecarboxanilide undergoes successive diarylation at the 4- and 5-positions accompanied by decarbamoylation. 相似文献
15.
A palladium-catalyzed, microwave assisted carbonylative reaction is described for the synthesis of benzamides from aryl bromides and primary or secondary amines. The developed method uses bis(cyclopentadienyldicarbonyliron) as a solid source of carbon monoxide to produce a diverse set of secondary and tertiary amides in 42–82% yield. 相似文献
16.
Margarita ShenglofDmitri Gelman Gary A MolanderJochanan Blum 《Tetrahedron letters》2003,44(47):8593-8595
Cerium trichloride, as well as some other lanthanide salts, promote the palladium-catalyzed cross-coupling of triethylaluminum with bromoarenes. The lanthanide compounds also increase the selectivity by diminishing the undesired hydrodebromination process. 相似文献
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[reaction: see text] Alkynyldimethylaluminum reagents are easily available from terminal alkynes and trimethylaluminum via a triethylamine-catalyzed metalation. These compounds can react with various aromatic and heterocyclic halides in the presence of palladium in a fast and efficient way. This catalyzed cross-coupling reaction provides a simple entry to numerous internal alkynes, using a readily available, inexpensive, and nontoxic metalating agent. 相似文献
19.
Palladium-catalyzed cross-coupling reactions are state-of-the art methods for synthesis of many important compounds. The development of the use of the phenol-derived sulfonated hydroxyl group in the coupling reactions is highly attractive as the hydroxyl group is commonly present in organic compounds and they are versatile alternatives to aryl halides in cross-coupling reactions. In this tutorial review, we summarize the current development of palladium-catalyzed cross-coupling reactions of aryl mesylates. 相似文献
20.
The bulky and electron-rich MOP type ligands and Pd(dba)2 combinations showed high efficiency for the coupling reactions of amino acids and inactive aryl halides to give N-aryl amino acids. Under the catalytic conditions, not only α-amino acids, but also β-, γ-, and δ-amino acids have been coupled with aryl chlorides in moderate to high yields; in the case of optically pure β-amino acids as substrates, the optical purities of the coupling products retained. 相似文献