- Nickel-catalyzed Heck reaction of cycloalkenes using aryl sulfonates and pivalates
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Nickel-catalyzed Heck reaction of cycloalkenes delivers unusual conjugated arylated isomers. Nickel(0) catalysts ligated by chelating dialkylphosphines effectively activate not only aryl triflates as electrophiles, but also less reactive aryl mesylates, t
- Zhou, Jianrong Steve,Huang, Xiaolei,Teng, Shenghan,Chi, Yonggui Robin
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supporting information
p. 3933 - 3936
(2021/04/26)
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- para-Selective arylation and alkenylation of monosubstituted arenes using thianthreneS-oxide as a transient mediator
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Using thianthreneS-oxide (TTSO) as a transient mediator,para-arylation and alkenylation of mono-substituted arenes have been demonstratedviaapara-selective thianthrenation/Pd-catalyzed thio-Suzuki-Miyaura coupling sequence under mild conditions. This reaction features a broad substrate scope, and functional group and heterocycle tolerance. The versatility of this approach was further demonstrated by late-stage functionalization of complex bioactive scaffolds, and direct synthesis of some pharmaceuticals, including Tetriprofen, Ibuprofen, Bifonazole, and LJ570.
- Chen, Xiao-Yue,Nie, Xiao-Xue,Wu, Yichen,Wang, Peng
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p. 5058 - 5061
(2020/05/18)
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- Preparation method of para-substituted aryl compound
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The invention discloses a preparation method of a para-substituted aryl compound shown as a formula (I) which is described in the specfication. The preparation method is characterized by comprising the following step of: subjecting an aryl sulfonium salt shown as a formula (II) which is described in the specfication and boride to a coupling reaction in a solvent in an inert atmosphere under the action of alkali and a palladium catalyst to obtain the para-substituted aryl compound. According to the method, mono-substituted aromatic hydrocarbon is taken as a substrate, the aryl sulfonium salt isconstructed in situ, and the palladium catalyst catalyzes the aryl sulfonium salt constructed in situ to undergo the Suzuki-Miyaura coupling reaction, so a mono-substituted aromatic hydrocarbon para-arylation or alkenylation product is constructed quickly and efficiently. The method is mild in conditions, high in substrate universality and wide in tolerance of a heterocyclic coupling substrate.
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- Novel Selective Approach to Terminally Substituted [n]Dendralenes
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Dendralenes are simple alkenes with cross-conjugated double bonds that are frequently synthesized due to being potentially valuable building blocks for the synthesis of more complex structures. The synthetic approaches to dendralenes are based on the cross-coupling reactions of electrophilic and nucleophilic synthons derived from geminally substituted ethylene. Our novel methodology for the synthesis of only terminally substituted [3]- and [4]dendralenes, as well as 2,3-disubstituted buta-1,3-dienes, involves the preparation of 1,2-disubstituted cyclobutenes from readily available 2-bromocyclobutanone and the subsequent thermal ring-opening reactions.
- Polák, Peter,Tobrman, Tomá?
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supporting information
p. 957 - 968
(2018/12/11)
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- Suzuki-Miyaura coupling of simple ketones via activation of unstrained carbon-carbon bonds
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Here, we describe that simple ketones can be efficiently employed as electrophiles in Suzuki-Miyaura coupling reactions via catalytic activation of unstrained C-C bonds. A range of common ketones, such as cyclopentanones, acetophenones, acetone and 1-indanones, could be directly coupled with various arylboronates in high site-selectivity, which offers a distinct entry to more functionalized aromatic ketones. Preliminary mechanistic study suggests that the ketone α-C-C bond was cleaved via oxidative addition.
- Xia, Ying,Wang, Jianchun,Dong, Guangbin
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supporting information
p. 5347 - 5351
(2018/05/03)
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- Regio- and enantioselective Baeyer-Villiger oxidation: Kinetic resolution of racemic 2-substituted cyclopentanones
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A kinetic resolution of racemic 2-substituted cyclopentanones via highly regio- and enantioselective Baeyer-Villiger oxidation has been successfully developed. The reaction could afford the normal 6-substituted δ-lactones in up to 98% ee and >19/1 regioselectivity. Meanwhile, the unreacted ketones were recovered in excellent ee values (up to 98%). It represents the best results of the kinetic resolution of racemic 2-substituted cyclopentanones via nonenzymic asymmetric BV oxidation.
- Zhou, Lin,Liu, Xiaohua,Ji, Jie,Zhang, Yuheng,Wu, Wangbin,Liu, Yangbin,Lin, Lili,Feng, Xiaoming
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supporting information
p. 3938 - 3941
(2014/08/18)
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- Kumada coupling of aryl, heteroaryl, and vinyl chlorides catalyzed by amido pincer nickel complexes
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A series of amido pincer complexes of nickel were examined for their catalysis in the Kumada cross-coupling reaction. The P,N,O-pincer nickel complexes tested are active catalysts for the cross-coupling of aryl, heteroaryl, and vinyl chlorides with aryl Grignard reagents. The reactions can proceed at room temperature and tolerate functional groups in aryl chlorides with the aid of LiCl and ZnCl2 additives (Figure presented).
- Liu, Ning,Wang, Zhong-Xia
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experimental part
p. 10031 - 10038
(2012/02/05)
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- A ligand free and room temperature protocol for Pd-catalyzed kumada-corriu couplings of unactivated alkenyl phosphates
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Kumada - Corriu cross-couplings of nonactivated cyclic and acyclic vinyl phosphates with aryl magnesium reagents afforded a series of 1,1-disubtituted alkenes in good yields for most cases when the reactions were performed at room temperature with the sim
- Gauthier, Delphine,Beckendorf, Stephan,Gogsig, Thomas M.,Lindhardt, Anders T.,Skrydstrup, Troels
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supporting information; experimental part
p. 3536 - 3539
(2009/09/30)
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- Arenediazonium o-benzenedisulfonimides as efficient reagents for Heck-type arylation reactions
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Arenediazonium o-benzenedisulfonimides can be used as new and efficient reagents for Heck-type arylation reactions of some common substrates containing C-C multiple bonds, namely ethyl acrylate, acrylic acid, acroleyne, styrene and cyclopentene. The reactions were carried out in an organic solvent, in the presence of Pd(OAc)2 as pre-catalyst, and gave rise to arylated products, for example, ethyl cinnamates, cinnamic acids, cinnamic aldehydes and stilbenes, possessing an (E)-configuration, and 1-arylcyclopentenes, in good to excellent yields. It is noteworthy that all the reactions led to the recovery, in greater than 80% yield, of o-benzenedisulfonimide, recyclable for the preparation of other diazonium salts.
- Artuso, Emma,Barbero, Margherita,Degani, Iacopo,Dughera, Stefano,Fochi, Rita
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p. 3146 - 3157
(2007/10/03)
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- Highly active, air-stable palladium catalysts for the C-C and C-S bond-forming reactions of vinyl and aryl chlorides: Use of commercially available [(t-Bu)2P(OH)]2PdCl2, [(t-Bu)2P(OH)PdCl2]2, and [[(t-Bu)2PO···H·· ·OP(t-B0. u)2]PdCl]2 as catalysts
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Air-stable palladium complexes [(t-Bu)2P(OH)]2PdCl2, [(t-Bu)2P(OH)PdCl2]2, and [[(t-Bu)2PO···H··· OP(t-Bu)2]PdCl]2 serve as efficient catalysts for a variety of cross-coupling reactions of vinyl and aryl chlorides with arylboronic acids, arylzinc reagents, and thiols to yield the corresponding styrene derivatives, biaryls, and thioethers. 31P NMR and mechanistic studies argue that the phosphinous acid ligands in the complexes can be deprotonated in the presence of a base to yield an electron-rich anionic species, which is likely a catalyst intermediate, and dimeric [[(t-Bu)2PO···H·· ·OP(t-Bu)2]PdCl]2 was isolated and cystallographically characterized. These anionic complexes are anticipated not only to accelerate the rate-determining oxidative addition of aryl chlorides but also to stabilize the palladium complexes in the catalytic cycle.
- Li, George Y.
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p. 3643 - 3650
(2007/10/03)
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- Air-stable trialkylphosphonium salts: simple, practical, and versatile replacements for air-sensitive trialkylphosphines. Applications in stoichiometric and catalytic processes.
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Trialkylphosphines furnish unusual, sometimes unique, reactivity in a range of transformations. Unfortunately, their utility is compromised by their sensitivity to oxidation. We have examined a simple but powerful strategy for addressing this problem: convert air-sensitive trialkylphosphines into air-stable phosphonium salts via protonation on phosphorus. These robust salts serve as direct replacements for the corresponding phosphines (simple deprotonation under the reaction conditions by a Bronsted base liberates the trialkylphosphine) in a diverse set of applications. [reaction: see text]
- Netherton,Fu
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p. 4295 - 4298
(2007/10/03)
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- Versatile catalysts for the Suzuki cross-coupling of arylboronic acids with aryl and vinyl halides and triflates under mild conditions
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Through the use of Pd2(dba)3/P(t-Bu)3 as a catalyst, a wide range of aryl and vinyl halides, including chlorides, undergo Suzuki cross-coupling with arylboronic acids in very good yield, typically at room temperature; through use of Pd(OAc)2/PCy3, a diverse array of aryl and vinyl triflates react cleanly at room temperature. Together, these two catalyst systems cover a broad spectrum of commonly encountered substrates for Suzuki couplings. Furthermore, they display novel reactivity patterns, such as the selective cross-coupling by Pd2(dba)3/P(t-Bu)3 of an aryl chloride in preference to an aryl triflate, and they can be used at low loading, even for reactions of aryl chlorides. Preliminary mechanistic work indicates that a palladium monophosphine complex is the active catalyst in the cross-coupling of aryl halides.
- Littke, Adam F.,Dai, Chaoyang,Fu, Gregory C.
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p. 4020 - 4028
(2007/10/03)
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- An efficient procedure for the synthesis of crystalline aryldiazonium trifluoroacetates - Synthetic applications
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We have developed a very mild procedure for the synthesis of crystalline aryldiazonium trifluoroacetate salts in high yields under anhydrous conditions. Over thirty mono- or polyfunctional aniline derivatives have been diazotized by this method, including water- and acid-sensitive substrates. The o- and p-hydroxyaryldiazonium salts, derived from the corresponding anilines, could be deprotonated by treatment with K2CO3 to yield pure diazoquinones. NMR and UV/Vis spectra have been recorded for all the synthesized salts; the data are in good agreement with the rather limited published data and constitute a first extensive report of 13C-NMR chemical shifts in diazonium salts. An excellent linear relationship emerged between Brown's substituent constants S+(p) and the 13C(ipso) chemical shifts. The diazonium salts obtained proved to be much more soluble in organic solvents than their tetrafluoroborate counterparts. They were tested in Pd-mediated coupling reactions of various carbon-carbon double bonds, and were found to give good yields within short reaction times under very mild conditions. We believe that diazonium trifluoroacetates represent a very attractive alternative to diazonium tetrafluoroborates.
- Colas, Christophe,Goeldner, Maurice
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p. 1357 - 1366
(2007/10/03)
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- Preparation of aryl cyclobutenes under mild and neutral conditions
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Aryl cyclobutyl acetates were converted to the corresponding aryl cyclobutenes with lithium bromide in good yields (50-97%) and in high purity.
- Juteau,Gareau
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p. 3795 - 3805
(2007/10/03)
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- Reactions of Azo and Azoxy Sulphones with Transition Metal Complexes. Part 7. Arylation of Olefins with Arylazoxy Aryl Sulphones Catalysed by a Palladium(0) Phosphine Complex
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The arylation of acyclic and cyclic olefins by arylazoxy aryl sulphones has been investigated in the presence of a palladium(0) catalyst in benzene.Both of the aryl groups of the arylazoxy aryl sulphones are found to participate in the arylation.Two equivalents of aryl-substituted olefins were obtained when the reactions were carried out at 80 deg C, whereas one equivalent of olefin was arylated at 120 deg C.A plausible catalytic cycle involving a diarylpalladium(II) species is proposed.
- Kamigata, Nobumasa,Fukushima, Takamasa,Satoh, Akira,Kameyama, Masayuki
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p. 549 - 553
(2007/10/02)
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- Arylation of Olefins by Arylazo Aryl Sulfones under Palladium(0) Catalysis
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Palladium(0)-catalyzed reaction of arylazo aryl sulfones with olefins in benzene at 80 deg C gave aryl-substituted olefins in good yield.Diarylpalladium(II) species was proposed as an intermediate in this reaction.
- Kamigata, Nobumasa,Satoh, Akira,Kondoh, Tetsuya,Kameyama, Masayuki
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p. 3575 - 3580
(2007/10/02)
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- REACTION OF DIAZONIUM SALTS WITH TRANSITION METALS-III. PALLADIUM(0)-CATALYZED ARYLATION OF UNSATURATED COMPOUNDS WITH ARENEDIAZONIUM SALTS
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Palladium (0) catalyzed reactions of arenediazonium salts for arylation of aliphatic and cyclic olefins and allylic alcohols, styrene and ethyl acrylate were studied.Effect of the olefinic compounds and other reaction variables on the arylation were presented.Arylpalladium species was proposed as the most plausible intermediated in this reaction.
- Kikukawa, K.,Nagira, K.,Wada, F.,Matsuda, T.
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