- Iridium-Catalyzed Enantioselective Allylic Substitution of Enol Silanes from Vinylogous Esters and Amides
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The enol silanes of vinylogous esters and amides are classic dienes for Diels-Alder reactions. Here, we report their reactivity as nucleophiles in Ir-catalyzed, enantioselective allylic substitution reactions. A variety of allylic carbonates react with these nucleophiles to give allylated products in good yields with high enantioselectivities and excellent branched-to-linear ratios. These reactions occur with KF or alkoxide as the additive, but mechanistic studies suggest that these additives do not activate the enol silanes. Instead, they serve as bases to promote the cyclometalation to generate the active Ir catalyst. The carbonate anion, which was generated from the oxidative addition of the allylic carbonate, likely activates the enol silanes to trigger their activity as nucleophiles for reactions with the allyliridium electrophile. The synthetic utility of this method was illustrated by the synthesis of the anti-muscarinic drug, fesoterodine.
- Chen, Ming,Hartwig, John F.
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- Stereoselective Synthesis of Vinylboronates by Rh-Catalyzed Borylation of Stereoisomeric Mixtures
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The stereoselective preparation of vinylboronates via rhodium-catalyzed borylation of E/Z mixtures of vinyl actetates is described, and this method was also extended to synthesis of vinyldiboronates. These transformations feature high functional group compatibility and mild reaction conditions. Control experiments support a mechanism that involved a Rh-catalyzed borylation-isomerization sequence. The isomerization of (Z)-vinylboronates to (E)-isomers was also demonstrated.
- Li, Shenhuan,Li, Jie,Xia, Tianlai,Zhao, Wanxiang
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supporting information
p. 462 - 468
(2019/03/28)
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- A cost-effective shortcut to prepare organoselenium catalysts via decarboxylative coupling of phenylacetic acid with elemental selenium
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An interesting decarboxylative coupling reaction of phenylacetic acid with elemental selenium was discovered and employed for the preparation efficient organoselenium catalysts for Baeyer–Villiger reaction and oxidative deoximation reaction. Compared with the traditionally used Grignard reagent method, the decarboxylative coupling reaction with selenium powders provides a shortcut for the preparation of organoselenium catalysts free of carcinogenic organohalide starting materials, toxic and odorous selenol intermediates and magnesium salt solid wastes. This may be helpful for reducing the cost of selenium catalysts to facilitate the application of organoselenium-catalyzed green reactions in large-scale production.
- Cao, Hongen,Liu, Mingxuan,Qian, Rongrong,Zhang, Xu,Yu, Lei
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- Carboxylic acid addition to terminal alkynes utilizing ammonium tagged Hoveyda-Grubbs catalyst supported on magnetically separable core/shell silica: A highly reusable and air compatible catalytic system
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In this study, the performance of ammonium tagged Hoveyda-Grubbs catalyst supported on magnetically separable core/shell silica gel was tested on carboxylic acid addition reactions to terminal alkynes using a variety of carboxylic acid derivatives under air atmosphere. The catalytic system was found to be compatible with air atmosphere and can tolerate even non-degassed solvents. The reaction parameters such as temperature, substrate/catalyst ratio and the effect of carboxylic acid on the selectivity and yield of the reaction were investigated in details. The reaction of arylacetylenes with acetic acid yielded the corresponding E-isomer with conversion values up to 99% with a catalytic loading of 1% Ru. The reusability of the catalyst was tested using acetic acid/benzoic acid and phenylacetylene in toluene at 85 °C under air atmosphere. The catalyst was found to be highly reusable and maintained its activity up to 11th run, reaching a conversion value of 83% with minimum ruthenium leaching.
- ?ztürk, Bengi ?zgün,Gürcü, Didar,?ehito?lu, Solmaz Karabulut
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- Cationic ruthenium complex of the formula [RuCl(2,6-diacetylpyridine)(PPh3)2]BArF and its catalytic activity in the formation of enol esters
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A new ruthenium 2,6-diacetylpyridine complex was synthesized and applied in the atom-economic synthesis of enol esters through Markovnikov-directed addition of carboxylic acids to terminal alkynes. The ruthenium complex [RuCl(dap)(PPh3)2]+BArF? was synthesized from [RuCl2(PPh3)2] and the corresponding ligand 2,6-diacetylpyridine (dap). The complex was characterized structurally. The new ruthenium complex was utilized under ambient conditions as a catalyst in the Markovnikov addition of carboxylic acids to terminal alkynes to afford the corresponding enol esters in 93% to 52% isolated yields (85 °C, 16 h reaction time, 1 mol% catalyst loading).
- Stark, Matthew J.,Tang, Douglas T.,Rath, Nigam P.,Bauer, Eike B.
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supporting information
p. 873 - 877
(2018/02/09)
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- Pd0.09Ce0.91O2-Δ: A sustainable ionic solid-solution precatalyst for heterogeneous, ligand free Heck coupling reactions
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A quick and easy method for the preparation of Pd2+ metal ion substituted in ceria, Pd0.09Ce0.91O2-δ solid solution oxide, is described. The Pd0.09Ce0.91O2-δ solid solution oxide was fully characterized by XRD, ICP-OES, BET, XPS, SEM, EDX, TEM, TGA and Raman spectroscopy. All characterization techniques strongly suggested that Pd2+ was successfully incorporated into the lattice structure of ceria. The effect of the reaction conditions on the catalytic properties of the Pd0.09Ce0.91O2-δ solid solution catalyst initially was studied in detail with the model Heck reaction of iodobenzene and methylacrylate to obtain optimum reaction conditions. The Pd0.09Ce0.91O2-δ solid solution catalyst then afforded substituted alkenes in good to excellent yields under these optimum reaction conditions. Steric and electronic effects were also studied, and were found to influence the catalytic activity. Characterization of the used catalyst suggests that Pd2+ in Pd0.09Ce0.91O2-δ is reduced in situ to Pd0 when employed in the Heck cross-coupling reactions. The catalyst was easily recovered by centrifuge and reused three times without significant loss of catalytic efficiency.
- Mpungose, Philani P.,Sehloko, Neo I.,Dasireddy, Venkata D.B.C.,Mahadevaiah, Narayanappa,Maguire, Glenn E.,Friedrich, Holger B.
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- Formyloxyacetoxyphenylmethane as an N-Formylating Reagent for Amines, Amino Acids, and Peptides
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Formyloxyacetoxyphenylmethane is a stable, water-tolerant, N-formylating reagent for primary and secondary amines that can be used under solvent-free conditions at room temperature to prepare a range of N-formamides, N-formylanilines, N-formyl-α-amino acids, N-formylpeptides, and an isocyanide.
- Chapman, Robert S. L.,Lawrence, Ruth,Williams, Jonathan M. J.,Bull, Steven D.
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supporting information
p. 4908 - 4911
(2017/09/23)
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- Organoselenium-catalyzed baeyer-villiger oxidation of α,β-unsaturated ketones by hydrogen peroxide to access vinyl esters
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By carefully screening the organoselenium pre-catalysts and optimizing the reaction conditions, simple dibenzyl diselenide was found to be the best pre-catalyst for Baeyer-Villiger oxidation of (E)-α,β-unsaturated ketones with the green oxidant hydrogen peroxide at room temperature. The organoselenium catalyst used in this reaction could be recycled and reused several times. This new method was suitable not only for methyl unsaturated ketones, but also for alkyl and aryl unsaturated ketones. Therefore, it provided a direct, mild, practical, highly functional group-tolerant process for the chemoselective preparation of the versatile (E)-vinyl esters from the readily available (E)-α,β-unsaturated ketones. A possible mechanism was also proposed to rationalize the activity of the organoselenium catalyst in the presence of hydrogen peroxide in this Baeyer-Villiger oxidation reaction.
- Zhang, Xu,Ye, Jianqing,Yu, Lei,Shi, Xinkang,Zhang, Ming,Xu, Qing,Lautens, Mark
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supporting information
p. 955 - 960
(2015/03/30)
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- Palladium-Catalyzed Arylation of Olefins by Triarylphosphines via C-P Bond Cleavage
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C-H Arylation of olefins by triarylphosphines via C-P bond cleavage has been achieved with either Pd0 or PdII catalysts. A variety of olefins and triarylphosphines are tolerated, and we inferred that both Pd0 and PdII could function directly without pre-oxidation or pre-reduction.
- Lu, Dapeng,Xu, Yu,Liu, Wenjing,Guo, Lijuan,Sun, Xingxia
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p. 116 - 122
(2015/10/19)
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- Iron-Catalyzed Cross-Coupling of Alkenyl Acetates
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Stable C-O linkages are generally unreactive in cross-coupling reactions which mostly employ more electrophilic halides or activated esters (triflates, tosylates). Acetates are cheap and easily accessible electrophiles but have not been used in cross-couplings because the strong C-O bond and high propensity to engage in unwanted acetylation and deprotonation. Reported herein is a selective iron-catalyzed cross-coupling of diverse alkenyl acetates, and it operates under mild reaction conditions (0 C, 2 h) with a ligand-free catalyst (1-2 mol%). Iron clad: Acetates are underutilized electrophiles in metal-catalyzed cross-coupling reactions because of the strong alkenyl C-O bond and their propensity to engage in unwanted reactions. Combination of a ligand-free low-valent Fe catalyst with nucleophilic organomagnesium reagents, low temperature, and short reaction times results in highly selective cross-couplings with alkenyl acetates.
- G?rtner, Dominik,Stein, André Luiz,Grupe, Sabine,Arp, Johannes,Von Wangelin, Axel Jacobi
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supporting information
p. 10545 - 10549
(2015/09/02)
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- General metal-free baeyer-villiger-type synthesis of vinyl acetates
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Oxone, a cheap, stable, and nonhazardous oxidizing reagent, transforms α,β-unsaturated ketones of defined stereochemistry into their corresponding vinyl acetates through a Baeyer-Villiger reaction. This process is general and straightforward, tolerating a
- Poladura, Belén,Martínez-Casta?eda, ángel,Rodríguez-Solla, Humberto,Llavona, Ricardo,Concellón, Carmen,Del Amo, Vicente
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p. 2810 - 2813
(2013/07/11)
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- A dinuclear ruthenium catalyst with a confined cavity: Selectivity in the addition of aliphatic carboxylic acids to phenylacetylene
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A dinuclear ruthenium catalyst with a rigid anthracene spacer shows excellent regio- and stereo-selectivity in the atom-economic addition of aliphatic carboxylic acids to phenylacetylene, producing exclusively anti-Markovnikov enol-esters with high E/Z ratios of the isomers.
- Cheung, Kwong-Chak,Wong, Wing-Leung,So, Ming-Him,Zhou, Zhong-Yuan,Yan, Siu-Cheong,Wong, Kwok-Yin
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supporting information
p. 710 - 712
(2013/03/13)
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- Synthesis and structure of [Ru(dppe)2(CH3CN)Cl] [BPh4] and its catalytic application to anti-Markovnikov addition of carboxylic acids to terminal alkynes
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The compound, [Ru(dppe)2(CH3CN)Cl][BPh4] (1) has been synthesized from the precursor complex, [(PPh3) 2Ru(CH3CN)3Cl][BPh4]. The complex has been structurally character
- Das, Uttam Kumar,Bhattacharjee, Manish
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experimental part
p. 78 - 82
(2012/03/12)
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- Steric control at the wingtip of a bis-N-heterocyclic carbene ligand: Coordination behavior and catalytic responses of its ruthenium compounds
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Changing the N-substituents of a methylene-linked bis-NHC ligand from n-butyl to bulky mesityl shifts ligand coordination from normal/normal to normal/abnormal mode. The mesityl wingtip groups afford [RuII( MesNHC(CH2)NHC
- Saha, Sayantani,Ghatak, Tapas,Saha, Biswajit,Doucet, Henri,Bera, Jitendra K.
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p. 5500 - 5505
(2012/11/07)
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- Ligand-controlled regio- and stereoselective addition of carboxylic acids onto terminal alkynes catalyzed by carbonylruthenium(0) complexes
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The addition of carboxylic acids onto terminal alkynes was catalyzed by mononuclear ruthenium(0) complexes to give enol esters in high yields. By using ligands with different electronic properties, product selectivity was achieved. E-enol esters were preferentially produced when tricarbonyl(η4- diene)ruthenium complexes were used; while geminal enol esters were produced when tricarbonylbis(phosphane)ruthenium complexes were used. Product selectivity is a major problem in transition metal-catalyzed hydrocarboxylation reactions. In this paper we report the ability of Ru(CO)3L2 (where L is a 2 e-donor) to catalyze the addition of variouscarboxylic acids onto terminal alkynes. A direct relationship between the regioselectivity of the product and the electronic property of the catalysis metal centre was observed.
- Tan, Sze Tat,Fan, Wai Yip
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experimental part
p. 4631 - 4635
(2011/02/27)
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- Thallium(III) chloride: A mild and efficient catalyst for acylation of alcohols, phenols and thiols, and for geminal diacylation of aldehydes under solvent-free conditions
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Thallium(III) chloride is a simple and efficient catalyst for acylation of alcohols, phenols and thiols. It is also very effective for geminal diacylation of aldehydes. The acylation reaction using acetic anhydride proceeds in excellent yield in the presence of catalytic amounts of thallium(III) chloride (1 mol%) at room temperature within relatively short reaction times (20 min). Structurally diverse alcohols, phenols, thiols and aldehydes undergo acylation under solvent-free conditions.
- Kadam, Santosh T.,Kim, Sung Soo
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experimental part
p. 3307 - 3313
(2009/05/07)
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- Immobilized ruthenium complexes bearing N,O-bidentate ligands
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Immobilization of a family of arene and benzylidene N,O-bidentate ruthenium complexes by covalently anchoring the homogeneous complexes on MCM-41 is described. Successful applications of these immobilized catalytic systems in enol-ester synthesis, Kharasch addition, ring-closing metathesis (RCM), ring-opening metathesis polymerization (ROMP) and atom transfer radical polymerization (ATRP) are illustrated. Important advantages of these heterogeneous catalyst systems in comparison with their homogeneous counterparts are also highlighted.
- Drǎgu?an, Valerian,Verpoort, Francis
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p. 905 - 915
(2008/09/20)
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- Regio- and stereoselective addition of carboxylic acids to phenylacetylene catalyzed by cyclopentadienyl ruthenium complexes
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The direct addition of carboxylic acids to terminal alkynes such as phenylacetylene in the presence of catalytic amount of [CpRu(CO)2Cl] (1) or [{CpRu(CO)2}2] (2) affords the anti-Markovnikov adducts with high selectivity. In most instances, the E-enol esters are the major products.
- Ye, Suming,Leong, Weng Kee
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p. 1117 - 1120
(2007/10/03)
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- Synthesis and structure of some ruthenium-rhenium heterodinuclear complexes and their catalytic activity in the addition of carboxylic acids to phenylacetylene
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The salt elimination reaction of Na[Re(CO)5] with Cp*Ru(dppm)Cl, CpRu(dppm)Cl or CpRu(CO)2Cl afforded the heterodinuclear species Cp*Ru(μ-CO)2(μ-dppm)Re(CO) 3, Cp(CO)Ru(μ-dppm)Re(CO)4, or Cp(CO) 2RuRe(CO)5, respectively, in moderate yields. An orthometallated species, Cp*(CO)Ru(μ-H)[μ-PhP(C6H 4)CH2PPh2]Re(CO)3, was also obtained from the first reaction. All these heterodinuclear products have been characterised crystallographically. They also showed good catalytic activity for the addition of carboxylic acids to phenylacetylene to afford the anti-Markovnikov products selectively.
- Ye, Suming,Leong, Weng Kee
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p. 1216 - 1222
(2007/10/03)
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- Catalytic application of a Ru-alkylidene in the nucleophilic addition of several carboxylic acids on terminal alkynes and the homo-coupling of 1-alkynes
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Thermal treatment of Ru-alkylidene (4) bearing a triazol-5-ylidene (NHC) ligand (2) at 110 °C and addition of a terminal alkyne generates a ruthenium vinylidene. The thermolysed Ru-alkylidene catalyses the vinylation and dimerisation of 1-alkynes. The nucleophilic addition of acetic acid on terminal alkynes proceeds smoothly and regioselective towards the Markovnikov addition. The addition reaction can be tuned by changing the acidity of the carboxylic acid. At increasing acidity, higher conversion of the triple bond is obtained and the vinylation/dimerisation ratio increases. The direct coupling between two 1-alkynes shows a reactivity order, which decreases from 1-octyne>1,7-octadiyne>phenylacetylene>3,3 dimethyl-1-butyne. The regioselectivity is strongly dependent on the nature of the terminal alkyne.
- Melis, Karen,De Vos, Dirk,Jacobs, Pierre,Verpoort, Francis
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p. 131 - 136
(2015/03/04)
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- Catalytic application of a Ru-alkylidene in the nucleophilic addition of several carboxylic acids on terminal alkynes and the homo-coupling of 1-alkynes
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Thermal treatment of Ru-alkylidene (4) bearing a triazol-5-ylidene (NHC) ligand (2) at 110°C and addition of a terminal alkyne generates a ruthenium vinylidene. The thermolysed Ru-alkylidene catalyses the vinylation and dimerisation of 1-alkynes. The nucleophilic addition of acetic acid on terminal alkynes proceeds smoothly and regioselective towards the Markovnikov addition. The addition reaction can be tuned by changing the acidity of the carboxylic acid. At increasing acidity, higher conversion of the triple bond is obtained and the vinylation/dimerisation ratio increases. The direct coupling between two 1-alkynes shows a reactivity order, which decreases from 1-octyne > 1,7-octadiyne > phenylacetylene > 3,3 dimethyl-1-butyne. The regioselectivity is strongly dependent on the nature of the terminal alkyne.
- Melis, Karen,De Vos, Dirk,Jacobs, Pierre,Verpoort, Francis
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p. 131 - 136
(2007/10/03)
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- Synthesis of enol esters and dimerization of terminal alkynes catalyzed by neutral and cationic vinylidene ruthenium complexes
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In the current study Ru(II) vinylidene complexes of the general type: Cl2Ru{=C=C(H)R}(PR′3)L (R = Ph, SiMe3, R′ = Ph, Cyclohexyl (Cy) and L = phosphine or N-heterocyclic carbene) are synthesized and tested for the addition of carboxylic acids to terminal alkynes. A careful choice of the catalytic system, substrate and carboxylic acid gives access to alk-1-en-2-yl esters, alk-1-en-1-yl esters or enyne dimerization products. Furthermore, an extension was made to synthesize an analogous 14-electron species by treating one of the complexes with AgBF4 and its influence on the catalytic activity and selectivity are investigated.
- Opstal, Tom,Verpoort, Francis
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p. 314 - 320
(2007/10/03)
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- A new heterogeneous hybrid ruthenium catalyst being an eco-friendly option for the production of polymers and organic intermediates
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We succeeded in synthesising and characterising a new heterogeneous hybrid ruthenium catalyst that exhibits excellent stability, reusability and leaching characteristics. The host-guest interaction is studied by XRD, XRF, ICP/MS, BET, FT-Raman and solid state NMR analysis. Moreover, we tested this catalytic system in ring-closing metathesis (RCM), ring-opening metathesis polymerization (ROMP), Kharasch addition, atom transfer radical polymerization (ATRP) and vinylation reactions. The results obtained from these tests show that for ROMP, RCM, Kharasch addition and vinylation reactions the heterogeneous catalyst possesses important advantages in comparison with its homogeneous analogue.
- De Clercq, Bob,Lefebvre, Frederic,Verpoort, Francis
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p. 1201 - 1208
(2007/10/03)
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- Ruthenium-catalyzed selective anti-Markovnikov trans addition of carboxylic acids and tail-to-tail dimerization of terminal alkynes
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Carboxylic acids react with terminal alkynes in the presence of a catalytic amount of RuClx(p-cymene)(triazol-5-ylidene) to selective generate Z-alk-1-en-1-yl esters. The anti-Markovnikov and trans addition on the terminal alkyne gives access t
- Melis, Karen,Samulkiewicz, Pawel,Rynkowski, Jacek,Verpoort, Francis
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p. 2713 - 2716
(2007/10/03)
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- Acid controlled alkyne dimerisation initiated by a Ru-carbene precursor
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The Grubb's catalyst Cl2(PR3)2Ru=CHPh (1) is an excellent precursor for the dimerisation of terminal alkynes. Thermal treatment and addition of two equivalents of phenylacetylene to complex 1 generates a new Ru-vinylidene (3). Complex 3 catalyses a selective product formation for trans-tail-to-tail enynes. Addition of acetic acid enhances the yield and the reaction rate dramatically and a reversed stereoselectivity for the formation of Z-isomers is obtained. The stereoselectivity can be easily tuned by addition of acetic acid. The influence of the acid on the reaction pathway has been revealed. A simple one-pot preparation of tail-totail enynes is established.
- Melis, Karen,De Vos, Dirk,Jacobs, Pierre,Verpoort, Francis
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p. 159 - 164
(2007/10/03)
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- Atom transfer radical addition and enol-ester synthesis catalyzed by Ru-vinylidene complexes
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Ru-vinylidene complexes, Cl2Ru{=C=C(H)tBut}(PCy3)(L) (L=PCy3 or N-heterocyclic carbenes) reveal themselves as a versatile catalyst for the atom transfer radical addition (ATRA) of polyhalogenated alkanes to olefins, such as methylmethacrylate, styrene and 1-octene. Furthermore, these systems are excellent catalysts for the nucleophilic addition of carboxylic acids to terminal alkynes and yielded exclusively alk-1-en-2-yl esters. These complexes can also be transformed to their cationic counterparts by treating the neutral complexes with AgBF4 and their catalytic potential in ATRA and vinylation reaction are investigated.
- Opstal, Tom,Verpoort, Francis
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p. 9259 - 9263
(2007/10/03)
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- Ring-closing metathesis, Kharasch addition and enol ester synthesis catalysed by a novel class of ruthenium(II) complexes
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Ruthenium Schiff base complexes I-III mediated the Kharasch addition of carbon tetrachloride across olefins with high yields which markedly depended on the catalyst and the substrate used. In addition, ring-closing metathesis of some representative diolefins was carried out. The best catalytic system III is able to form tri- and tetrasubstituted double bond products. Finally, dependent of the catalytic system and the reaction conditions used, these systems can catalyse the stereoselective formation of enol esters or enynes in excellent yields.
- De Clercq, Bob,Verpoort, Francis
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p. 8959 - 8963
(2007/10/03)
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- Solvolysis of styryliodonium salt: Products, rates, and mechanisms
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The solvolysis of phenyl[(E)-styryl]iodonium tetrafluoroborate in various solvents was examined at 50-70°C by means of product and kinetic studies with the normal and labeled substrates. The reactions involved are α-elimination and substitutions with configurational retention and inversion. In methanol and ethanol, the main reaction is α-elimination, along with about 5% of substitution with the ratio of inversion/retention from 4/6 to 3/7. As the basicity of the solvent decreases, the reaction rate and the fraction of α-elimination decrease, and at the same time the ratio of inversion/retention of substitution also decreases. In 2,2,2- trifluoroethanol, only the substitution with retention was observed. Labeling experiments showed that complete isotope scrambling occurred between the olefinic hydrogens of the retained product while the deuterium remained at the original position of the inverted product. The substitution mechanism is concluded to involve parallel pathways: an S(N) 1-type with a vinylenebenzenium ion intermediate leading to retention and a vinylic S(N) 2- type with a direct attack by the nucleophilic solvent leading to inversion.
- Okuyama, Tadashi,Ishida, Yoshimi,Ochiai, Masahito
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p. 163 - 170
(2007/10/03)
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- General Synthesis of (Z)-Alk-1-en-1-yl Esters via Ruthenium-Catalyzed anti-Markovnikov trans-Addition of Carboxylic Acids to terminal Alkynes
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The direct addition of carboxylic acids to terminal alkynes in the presence of catalytic amounts of (bis(diphenylphosphino)alkane)Ru(η3-methallyl)2 complexes provides a novel selective route to (Z)-alk-1-en-1-yl esters.This reaction involves an
- Doucet, Henri,Martin-Vaca, Blanca,Bruneau, Christian,Dixneuf, Pierre H.
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p. 7247 - 7255
(2007/10/03)
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- Styryl coupling vs. styryl acetate formation in reactions of styryl tellurides with palladium(II) salts
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In sharp contrast to the expected formation of a telluride-palladium complex, the treatment of either (E,E)- and (Z,Z)-distyryl tellurides (1 and 2) or (E)- and (Z)-styryl phenyl tellurides (5 and 6) with Li2PdCl4 in acetonitrile at 25 deg C results in the formation of stereoisomeric 1,4-diphenylbuta-1,3-dienes, whereas the treatment of 1 and 2 with Pd(OAc)2 produces styryl acetates solely or mainly.
- Uemura, Sakae,Takahashi, Hidetaka,Ohe, Kouichi
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- SYNTHESIS OF ENOL ESTERS FROM TERMINAL ALKYNES CATALYZED BY RUTHENIUM COMPLEXES
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Regioselective enol ester formation results from the addition of saturated and unsaturated carboxylic acids to phenylacetylene in the presence of RuCl3, RuCl3/2PR3 or RuCl2(PMe3)(arene) catalysts.
- Ruppin, Christophe,Dixneuf, Pierre H.
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p. 6323 - 6324
(2007/10/02)
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- Stereoselectivity in the Synthesis of Enol Esters from Chloromercurio Aldehydes and Acyl Chlorides
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Reactions of chloromercurio aldehydes with acyl chlorides gave a variety of (Z)- and (E)-enol esters.The Z/E ratio of the enol esters is dependent on the structure of chloromercurio aldehydes but independent of that of acyl chlorides.Z-Rich enol esters were prepared by acylation of 2-chloromercurio aldehydes derived from propanal, butanal, and 2-phenylethanal, while E-rich 1-acyloxy-1,3-butadiene was obtained by acylation of (E)-4-chloromercurio-2-butenal.Reaction mechanisms for the stereoselective formation of these enol esters are discussed together with the isomer composition of starting enol acetates from which the chloromercurio aldehydes were prepared.
- Fukuda, Wakichi,Sato, Hozumi,Kakiuchi, Hiroshi
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p. 751 - 756
(2007/10/02)
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- Arylation of Olefins by N-Nitroso-N-arylacetamides under Palladium(0) Catalysis: A New Precursor of Arylpalladium Species
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Olefins (styrene, octene-1, cycloheptene, ethyl acrylate, and vinyl acetate) were easily arylated in good yields with N-nitroso-N-arylacetamides (ArN(NO)COCH3: Ar= Ph, 4-MeC6H4, 4-MeOC6H4, 4-ClC6H4, 4-BrC6H4, and 4-IC6H4) under palladium(0) catalysis at 40 deg C within 40 min.
- Kikukawa, Kiyoshi,Naritomi, Masaki,He, Gong-Xin,Wada, Fumio,Matsuda, Tsutomu
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p. 299 - 301
(2007/10/02)
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