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1.
An unusual ligand-dependent chemoselective Suzuki-Miyaura cross-coupling reaction for 3-bromo-4-trifloyl-thiophenes was discovered. Pd(PPh3)4 showed selectivity for triflate over bromide, whereas the selectivity was reversed for Pd(tBu3P)2. 相似文献
2.
To introduce the biaryl structure as a triazine functionality, we have developed a new synthetic route via the Suzuki cross-coupling reaction of resin-bound chlorotriazines. The Suzuki cross-coupling reaction was achieved using various arylboronic acids, Pd(PPh3)4, Cs2CO3, and dioxane. With the integration of this chemistry and our previous orthogonal methodology, the triazine library is greatly expanded to a biaryl scaffold. 相似文献
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4.
Alice Collier 《合成通讯》2013,43(24):3713-3721
Abstract Reaction conditions for the Suzuki–Miyaura cross‐coupling of unprotected halopurine nucleosides with arylboronic acids in aqueous media were investigated. A series of arylated purine nucleosides was prepared in water without an organic cosolvent, using either Pd(PPh3)4 or Pd(OAc)2/TPPTS as the catalyst. 相似文献
5.
Alberto Scrivanti Valentina Beghetto Simonetta Antonaroli Federica Mandoj Bruno Crociani 《Tetrahedron letters》2004,45(30):5861-5864
The iminophosphine-palladium(0) complex [Pd(dmfu)(P-N)] [dmfu=dimethyl fumarate; P-N=2-(PPh2)C6H4-1-CHNC6H4-4-OMe] is a very efficient catalyst for the Suzuki coupling. In the reaction of aryl bromides with phenylboronic acid, turnover numbers up to ca. 200,000 are obtained at 110 °C in 2 h. Good rates are obtained also with the sterically hindered and electronically deactivated 2-bromo-1,3,5-trimethylbenzene. The complex is able to catalyze the exhaustive arylation of 2,3,7,8,12,13,17,18-octabromo-5,10,15-triphenylcorroleCu(III) to yield the corresponding undecaaryl substituted derivative. 相似文献
6.
Cristina Sicre 《Tetrahedron》2006,62(48):11063-11072
2,4-Dibromopyridine undergoes a regioselective Suzuki cross-coupling reaction at position 2 with several alkenyl(aryl) boronic acids to render 4-bromo-2-carbon substituted pyridines, difficult to be prepared otherwise, in good yields under palladium catalysis, either Pd(PPh3)4/TlOH or Pd2dba3/PCy3/K3PO4 at 25 °C. This behavior is explained on the basis of the electrophilic character of both C-Br bonds, being their relative reactivity in 2,4-dibromopyridine similar to that in the corresponding monobromopyridines. In addition, the dicoupled compound 6 is not formed through a double oxidative addition of 2,4-dibromopyridine to Pd(PPh3). 相似文献
7.
Jianjun Xu 《Journal of fluorine chemistry》2007,128(1):71-77
A straightforward method to prepare symmetrical (1Z, 3Z)- and (1E, 3E)-2,3-difluoro-1,4-disubstituted-buta-1,3-dienes is described. High E/Z ratio 1-bromo-1-fluoroalkenes, prepared by isomerization from the E/Z ≈ 1:1 isomeric mixtures, reacted with Bu3SnSnBu3 and Pd(PPh3)4 to afford (1Z, 3Z)-2,3-difluoro-1,4-disubstituted-buta-1,3-dienes in good yield. (Z)-1-Bromo-1-fluoroalkenes, which were prepared by kinetic reduction from 1-bromo-1-fluoroalkenes (E/Z ≈ 1:1), can undergo similar reaction with Bu3SnSnBu3 and Pd(PPh3)4/CuI to prepare (1E, 3E)-2,3-difluoro-1,4-disubstituted-buta-1,3-dienes. 相似文献
8.
Qibo Liu 《Journal of fluorine chemistry》2009,130(10):922-925
(E)-(1,2-Difluoro-1,2-ethenediyl)bis[tributylstannane], 3, readily undergoes a Pd(PPh3)4/CuI-catalyzed cross-coupling reaction with iodotrifluoroethene to yield (E)-octafluoro-1,3,5-hexatriene, 4, in high isomeric purity. (1Z,3E,5Z)-(1,2,3,4,5,6-Hexafluoro-1,3,5-hexenetriyl)bis[tributylstannane], 7, was sequentially prepared from (1Z,3E,5Z)-(1,2,3,4,5,6-hexafluoro-1,3,5-hexenetriyl)bis[triethylsilane], 5, which was prepared via a Pd(PPh3)4/CuI-catalyzed cross-coupling reaction of 3 with (E)-1,2-difluoro-1-iodo-2-triethylsilylethene, 6. Pd(PPh3)4/CuI cross-coupling of 7 with iodotrifluoroethene gave (3E,5E,7E)-dodecafluoro-1,3,5,7,9-decapentaene, 8. 相似文献
9.
Hamao Watanabe Masayuki Saito Naotake Sutou Kazuya Kishimoto Jun Inose Yoichiro Nagai 《Journal of organometallic chemistry》1982,225(1):343-356
Addition of chloromethyl- and methoxymethyldisilanes, X3-mMemSiSiMen-X3-n (X - Cl and OMe;m, n - 0-2), as well as hexamethyldisilane, to allene and 1, 2-butadiene in the presence of Pd(PPh3)4 catalyst gave regioselectively new functionalized organosilicon compounds, 2, 3-bis(organosilyl)prop-1-enes and 2, 3-bis(organosilyl)but-1-enes, respectively. Other group VIII metal-phospine complexes also affected the reaction, but results were found to be less satisfactory. Also, the reaction of any unsymmetrical disilane with an allenic compound gave only a single product; e.g., the addition of chloropentamethyldisilane to 1, 2-butadiene in the presence of Pd(PPh3)4 gave CH2-C(SiMe3)CH(SiMe2Cl)Me in 93% yield. 相似文献
10.
Novel base-free Suzuki-type cross-coupling reaction by the use of triarylantimony diacetates and arylboronic acids in the presence of Pd(PPh3)4 catalyst led to the formation of biaryl derivatives in moderate to excellent yields. The reaction is applicable to a variety of arylboronic acids bearing base-sensitive functional groups. 相似文献
11.
Chun-Lin Li 《Journal of fluorine chemistry》2010,131(8):856-5077
A highly efficient Suzuki reaction between N-aryltrifluoroacetimidoyl chlorides and aryl boronic acids using Pd(PPh3)4 as a catalyst has been developed. This route allows for selective synthesis of N-aryl trifluoromethylarylketoimines in high yields under mild reaction conditions. 相似文献
12.
《Tetrahedron letters》1988,29(32):3983-3986
The reaction of 9-alkyl-9-BBNs with 1-bromo-1-phenylthioethene or (E)- and (Z)-2-bromo-1-phenylthio-1-alkenes takes place readily in the presence of Pd(PPh3)4 and sodium hydroxide to afford stereodefined vinylic sulfides in excellent yields. 相似文献
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En-Chiuan Chang Ya-Lan Wen Chun-Hsi Chang Yun-Hwei Shen Shaw-Bing Wen Mou-Yung Yeh Fung Fuh Wong 《Tetrahedron》2012,68(29):5920-5924
Two regioisomers of 2-arylpyrazolo[3,4-c]quinolin-4(5H)-ones and 2-arylpyrazolo[4,3-c]quinolin-4(5H)-ones were synthesized by utilizing 3-arylsydnones, ethyl 3-bromopropynoate, and 2-aminophenylboronic acid pinacol ester in presence of catalytic agent Pd(PPh3)4. This efficient one-pot synthesis methodology involved 1,3-dipolar cycloaddition, Suzuki coupling reaction, and intramolecular cyclization three sequence steps. 相似文献
15.
Thienylmercury(II)chloride reacts with [Pd(PPh3)2Cl2], [Pd(PPh3)4] and [Pt(PPh3)4] to afford new compounds containing a metal-2-thienyl linkage. The compound [Pd(PPh3)2(2-C4H3S)Cl] probably has trans stereochemistry.2-Bromothiophen undergoes oxidative addition with [Pd(PPh3)4] and [Pt(PPh3)4], probably via a radical mechanism. With [Pd(CO)(PPh3)3], a carbonyl inserted product is obtained. The bromo-metal(II) complexes have trans stereochemistry. The course of the reaction between 3-methyl-2-bromothiophen and Pd(PPh3)4 is more complex. Thus, there is evidence of some cis bromopalladium(II) compounds amongst the products, also there is good evidence to support the view that some isomerisation of 3-methyl-2-thienyl to 4-methyl-2-thienyl occurs during the reaction, thus giving greater molar quantities of [Pd(PPh3)2(4-CH3-2-C4H2S)Br] than can be accounted for from any initial 4-methyl-2-bromothiophen impurity.The metallation of the thiophen ring, probably in the 4-position, with palladium(II) is described for 3-theylidene-4-methylaniline. 相似文献
16.
Madhu Ganesh 《Tetrahedron》2007,63(48):11973-11983
(Z)-α-Bromo-β-substituted nitroethylenes undergo facile Suzuki coupling with aryl, heteroaryl, and vinylboronic acids in the presence of Pd(PPh3)4 as catalyst to afford (E)-α,β-disubstituted nitroethylenes in high yield (up to 95%) and complete specificity. Similar coupling of α-bromonitroethylenes with terminal acetylenes (Sonogashira coupling) provides a novel route to (E)-nitroenynes. These Pd-catalyzed coupling methods offer a convenient and stereospecific entry into a diverse array of synthetically and biologically useful α,β-disubstituted nitroethylenes. 相似文献
17.
Sergey S. Patrushev Tatyana V. Rybalova Igor D. Ivanov Valentin A. Vavilin Elvira E. Shults 《Tetrahedron》2017,73(19):2717-2726
The eudesmane-type methylene lactones (isoalantolactone, alantolactone, 4,15-epoxyisoalantolactone, 2′,2′-dichloro-4H-spiro[cyclopropane-1′,4-eudesma-11(13)-en-8β,12-olide], and alantolactone) react with 8-bromoxanthines (8-bromocaffeine, 8-bromotheobromine, 8-bromo-3-butyltheobromine, 8-bromotheophylline, 8-bromo-9-butyltheophylline) under Heck reaction conditions to produce the target (E)-13-(2,6-dioxo-2,3-dihydro-1H-purin-8-yl)eudesma-4(15),11(13)-dien-8β,12-olides and the subsequent endocyclic isomers - 11-(2,6-dioxo-2,3-dihydro-1H-purin-8-yl)-13-normethyleudecma-4(15)-7(11)-dien-8α,12-olides. It was revealed that the yield and product ratio depends on the reaction conditions and the structure of methylene lactone. The effectiveness of Pd(OAc)2–caffeine catalytic system has been demonstrated in this reaction. The electric eel acetylcholinesterase inhibitory activity of the eudecmanolide-xanthine hybrids was evaluated. Among the new type bisheterocycles compound 27 with butyl and 2-oxodecahydronaphtho[2,3-b]furan-3(2H)-ylidene)methyl substituents at C-7 and C-8 of the xanthine core showed moderate activity with IC50 value of 40 μM. 相似文献
18.
Ring closing metathesis (RCM) of 8,9-diallylpurines or 9-butenyl-8-vinylpurines with the Grubbs 2nd generation catalyst resulted in fused 6,9- or 8,9-dihydropyrido[e]purines, respectively. The 8,9-dialkenylpurines were prepared from 8-bromopurines after 9-alkenylation and subsequent Stille coupling at C-8 with alkenylstannanes in the presence of Pd(PPh3)4 or Pd(PPh3)2Cl2. 相似文献
19.
Ulf Wellmar Anna-Britta Hrnfeldt Salo Gronowitz 《Journal of heterocyclic chemistry》1995,32(4):1159-1163
The Suzuki Pd(0)-catalyzed coupling between arylboronic acids and aryl bromides or iodides in weakly alkaline medium, previously further developed by us, has been used for regioselective preparation of 5-(2′-bromo-5′-furyl)-, 5-(2′-bromo-4′-furyl)-, 5-(2′-bromo-5′-thienyl)-, 5-(2′-bromo-4′-thienyl)-, 5-(4′-bromo-2′-thiazolyl)-, 5-(3′-bromophenyl)-, 5-(6′-bromo-2′-pyridyl)- and 5-(4′-bromo-2′-pyrimidyl)-substituted 2,4-di-t-butoxypyrimidines. In the coupling between 2,4-di-t-butoxy-5-pyrimidineboronic acid and the nine different aryl dibromides that were tried as coupling partners, only the 2,4- and 2,5-dibromothiazoles did not give satisfactory yields, 15% and 0%, respectively. The other seven aryl dibromides gave the desired 5-(bromoaryl)-2,4-di-t-butoxypyrimidines in 58-89% yield. Attempts to synthesise 2,4-di-t-butoxy-5-(2′-bromo-4′-thienyl)pyrimidine from 2-bromo-4-iodothiophene failed. Dealkylation of the 5-(bromoaryl)-2,4-di-t-butoxypyrimidines in 2.5 M hydrochloric acid gave the corresponding 5-(bromoaryl)uracils in almost quantitative yields. 相似文献
20.
Weiwei Li Yang Han Binsong Li Caiming Liu Zhishan Bo 《Journal of polymer science. Part A, Polymer chemistry》2008,46(13):4556-4563
Zero‐valent palladium complex, Pd(PTh3)3, with three tri(2‐thienyl)phosphine ligands was prepared and characterized. Pd(PTh3)3 is superior to Pd(PPh3)4 in catalyzing Suzuki‐Miyaura coupling and polymerization of thiophene‐based derivatives. The Suzuki polycondensation of 3‐hexyl‐5‐iodothiophene‐2‐boronic pinacol ester with Pd(PTh3)3 as the catalyst precursor afforded high‐molecular‐weight P3HT with high regularity and yield. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4556–4563, 2008 相似文献