- Room-temperature Pd-catalyzed methoxycarbonylation of terminal alkynes with high branched selectivity enabled by bisphosphine-picolinamide ligand
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We report the room-temperature Pd-catalyzed methoxy-carbonylation with high branched selectivity using a new class of bisphosphine-picolinamide ligands. Systematic optimization of ligand structures and reaction conditions revealed the significance of both
- Chen, Fen-Er,Ke, Miaolin,Liu, Ding,Ning, Yingtang,Ru, Tong
-
supporting information
p. 1041 - 1044
(2022/01/28)
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- Palladium-Catalyzed Asymmetric Hydroesterification of α-Aryl Acrylic Acids to Chiral Substituted Succinates
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A palladium-catalyzed asymmetric hydroesterification of α-aryl acrylic acids with CO and alcohol was developed, preparing a variety of chiral α-substituted succinates in moderate yields with high ee values. The kinetic profile of the reaction progress revealed that the alkene substrate first underwent the hydroesterification followed by esterification with alcohol. The origin of the enantioselectivity was elucidated by density functional theory computation.
- Ji, Xiaolei,Shen, Chaoren,Tian, Xinxin,Dong, Kaiwu
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supporting information
p. 8645 - 8649
(2021/10/25)
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- Investigation of the Mechanism Behind Conductive Fluorescent and Multistimuli-responsive Li+-enriched Metallogel Formation
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A fluorescent metallogel (2.6 % w/v) has been obtained from two non-fluorescent components viz. phenyl-succinic acid derived pro-ligand H2PSL and LiOH (2 equiv.) in DMF. Li+ ion not only plays a crucial role in gelation through aggre
- Dixit, Manish K.,Dubey, Mrigendra,Kalam, Abul,Kumar, Yeeshu,Mahendar, Chinthakuntla,Sharma, Vinay K.,Shukla, Jay
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p. 3020 - 3028
(2020/09/04)
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- Stereoconvergent Reduction of Activated Alkenes by a Nicotinamide Free Synergistic Photobiocatalytic System
-
There is a growing interest in developing cooperative chemoenzymatic reactions to harness the reactivity of chemical catalysts and the selectivity of enzymes for the synthesis of nonracemic chiral compounds. However, existing chemoenzymatic systems with m
- Wang, Yajie,Huang, Xiaoqiang,Hui, Jingshu,Vo, Lam Tung,Zhao, Huimin
-
p. 9431 - 9437
(2020/10/06)
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- Synergetic Catalysis for One-pot Bis-alkoxycarbonylation of Terminal Alkynes over Pd/Xantphos?Al(OTf)3 Bi-functional Catalytic System
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Tandem bis-alkoxycarbonylation of alkynes allows for the preparation of 2-substituted succinates from alkynes and nucleophile alcohol via two successive alkoxycarbonylation with advantages of 100 % atomic economy and simplified one-pot operation. Herein, the one-pot tandem bis-alkoxycarbonylation of alkynes was accomplished over the bi-functional catalytic system containing Xantphos-modified Pd-complex and Lewis super-acid of Al(OTf)3. It was found that, via the synergetic catalysis, the involved Xantphos-modified Pd-complex was responsible for the activation of CO and the alkynes through coordination to Pd-center while Al(OTf)3 was in charge of the activation of the alcohol to facilitate the formation of [Pd?H]+ active species. The in situ high-pressure FT-IR analysis, coupled with 1H/13C NMR spectral characterizations, confirmed that the introduced Al(OTf)3 with intensive oxophilicity (via acid-base pair interaction) was able to activate nucleophilic MeOH to be a reliable proton-donor (i. e. hydride-source) to warrant the formation and stability of [Pd?H]+ species upon the oxidation of Pd0 by H+ (Pd0+H+→[PdII?H]+). Over the developed bi-functional catalytic system, the yields of the target diesters were obtained in the range of 36~86 % in this sequence with the wide substrate scope.
- Guo, Wen-Di,Liu, Lei,Yang, Shu-Qing,Chen, Xiao-Chao,Lu, Yong,VO-Thanh, Giang,Liu, Ye
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p. 1376 - 1384
(2020/01/24)
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- Diversion of the Arbuzov reaction: Alkylation of C-Cl instead of phosphonic ester formation on the fullerene cage
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We report an "inversed" Arbuzov reaction of the fullerene derivatives C60Ar5Cl with trialkyl phosphites P(OR)3 producing alkylated fullerene derivatives C60Ar5R (R = Me, Et, iPr, nBu) with almost quantitative yields. This reaction provides a convenient synthetic route for the preparation of a large variety of functionalized fullerene derivatives with tailored properties, e.g. water-soluble compounds demonstrating promising antiviral activities against HCMV, HSV1, HIV and several influenza virus strains.
- Kraevaya, Ol'Ga A.,Peregudov, Alexander S.,Troyanov, Sergey I.,Godovikov, Ivan,Fedorova, Natalya E.,Klimova, Regina R.,Sergeeva, Vasilina A.,Kameneva, Larisa V.,Ershova, Elizaveta S.,Martynenko, Vyacheslav M.,Claes, Sandra,Kushch, Alla A.,Kostyuk, Svetlana V.,Schols, Dominique,Shestakov, Alexander F.,Troshin, Pavel A.
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supporting information
p. 7155 - 7160
(2019/08/07)
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- Autoinductive conversion of α,α-diiodonitroalkanes to amides and esters catalysed by iodine byproducts under O2
-
Studies to convert nitroalkanes into amides and esters using I2 and O2 revealed in situ-generated iodine species facilitate the homolytic C-I bond cleavage of α,α-diiodonitroalkanes, arguably in an autoinductive or autocatalytic manner. Consequently, we devised a rapid and economical I2/O2-based method to synthesise sterically hindered esters directly from primary nitroalkanes.
- Li, Jing,Lear, Martin J.,Hayashi, Yujiro
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supporting information
p. 6360 - 6363
(2018/06/21)
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- Development of efficient palladium catalysts for alkoxycarbonylation of alkenes
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Herein, we report a general and efficient Pd-catalysed alkoxycarbonylation of sterically hindered and demanding olefins including a variety of tri-, tetra-substituted and 1,1-disubstituted alkenes. In the presence of 1,3-bis(tert-butyl(pyridin-2-yl)phosphanyl)propane L3 or 1,4-bis(tert-butyl(pyridin-2-yl)phosphanyl)butane L4 the desired esters are obtained in good yields and selectivities. Similar transformation is obtained using tertiary ether as showcased in the carbonylation of MTBE to the corresponding linear ester in high yield and selectivity.
- Liu, Jiawang,Dong, Kaiwu,Franke, Robert,Neumann, Helfried,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 12238 - 12241
(2018/11/21)
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- Selective Palladium-Catalyzed Carbonylation of Alkynes: An Atom-Economic Synthesis of 1,4-Dicarboxylic Acid Diesters
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A class of novel diphosphine ligands bearing pyridine substituents was designed and synthesized for the first time. The resulting palladium complexes of L1 allow for chemo- and regioselective dialkoxycarbonylation of various aromatic and aliphatic alkynes affording a wide range of 1,4-dicarboxylic acid diesters in high yields and selectivities. Kinetic studies suggest the generation of 1,4-dicarboxylic acid diesters via cascade hydroesterification of the corresponding alkynes. Based on these investigations, the chemo- and regioselectivities of alkyne carbonylations can be controlled as shown by switching the ligand from L1 to L3 or L9 to give α,β-unsaturated esters.
- Liu, Jiawang,Dong, Kaiwu,Franke, Robert,Neumann, Helfried,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 10282 - 10288
(2018/08/03)
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- Co-catalysis over a bi-functional ligand-based Pd-catalyst for tandem bis-alkoxycarbonylation of terminal alkynes
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A bi-functional ligand (L1) containing a diphosphino fragment and sulfonic acid group (-SO3H) enabled PdCl2(MeCN)2 to efficiently catalyze the tandem bis-alkoxycarbonylation of terminal alkynes to produce aryl-/alkyl-substituted succinate (α,ω-diesters). It was found that the -SO3H incorporated in L1 indispensably assisted the Pd-catalyst in accomplishing this tandem reaction via intramolecular synergic effects. Co-catalysis over the L1-based Pd-catalyst was not due to the physical mixture of Xantphos and MeSO3H. In situ FTIR analysis verified that the formation and stability of Pd-H active species were facilitated by the presence of L1. The formation of stabilized diacylpalladium intermediate (F) was the critical driving force for the second-step methoxycarbonylation. DFT calculation was carried out to optimize the geometric structure of F, which indicated that the developed intramolecular O?H hydrogen bonds were an important structural feature to stabilize F. In addition, the L1-based Pd-catalyst could be recycled successfully for at least 3 runs in the ionic liquid [Bmim]NTf2 without obvious activity loss and detectable metal leaching.
- Yang, Da,Liu, Huan,Wang, Dong-Liang,Luo, Zhoujie,Lu, Yong,Xia, Fei,Liu, Ye
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supporting information
p. 2588 - 2595
(2018/06/11)
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- Direct β-Selective Hydrocarboxylation of Styrenes with CO2 Enabled by Continuous Flow Photoredox Catalysis
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The direct β-selective hydrocarboxylation of styrenes under atmospheric pressure of CO2 has been developed using photoredox catalysis in continuous flow. The scope of this methodology was demonstrated with a range of functionalized terminal styrenes, as well as α-substituted and β-substituted styrenes.
- Seo, Hyowon,Liu, Aofei,Jamison, Timothy F.
-
supporting information
p. 13969 - 13972
(2017/10/17)
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- A highly efficient Pd/CuI-catalyzed oxidative alkoxycarbonylation of α-olefins to unsaturated esters
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A new protocol for the alkoxycarbonylation of α-olefins to the corresponding unsaturated esters has been developed. Differently substituted styrenes were selectively converted to cinnamate derivatives, via C[sbnd]H bond functionalization. Various palladium sources, including heterogeneous ones, in combination with CuI exhibited a high catalytic efficiency using oxygen as the most cheap oxidant. Monocarbonylated products were obtained in good yields and high chemoselectivity working with a low CO pressure (2 atm) and an excess of air (35 atm) avoiding in this way explosion risks. Commercial cinnamate derivatives were prepared in good to excellent yields by this very simple one-pot procedure.
- Maffei, Mathias,Giacoia, Gabriele,Mancuso, Raffaella,Gabriele, Bartolo,Motti, Elena,Costa, Mirco,Della Ca’, Nicola
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p. 435 - 443
(2016/12/16)
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- N,N-Dimethylformamide as Hydride Source in Nickel-Catalyzed Asymmetric Hydrogenation of α,β-Unsaturated Esters
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Asymmetric transfer hydrogenation of α,β-unsaturated esters is realized by using a nickel/bisphosphine catalyst and N,N-dimethylformamide (DMF) as the hydride source.
- Guo, Siyu,Zhou, Jianrong
-
supporting information
p. 5344 - 5347
(2016/11/02)
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- Nickel-catalyzed asymmetric transfer hydrogenation of conjugated olefins
-
Asymmetric transfer hydrogenation of electron-deficient olefins is realized with nickel catalysts supported by strongly σ-donating bisphosphines. Deuterium labeling experiments point to a reaction sequence of formate decarboxylation, asymmetric hydride in
- Guo, Siyu,Yang, Peng,Zhou, Jianrong
-
supporting information
p. 12115 - 12117
(2015/07/28)
-
- Selective aryl α-diimine/palladium-catalyzed bis-alkoxycarbonylation of olefins for the synthesis of substituted succinic diesters
-
Aryl α-diimine derivatives have been used, for the first time, as efficient new ligands for the palladium-catalyzed oxidative bis-alkoxycarbonylation reaction of olefins. The most active catalyst was formed in situ from bis(9-anthryl)-2,3-dimethyl-1,4-dia
- Fini, Francesco,Beltrani, Michela,Mancuso, Raffaella,Gabriele, Bartolo,Carfagna, Carla
-
supporting information
p. 177 - 184
(2015/01/30)
-
- Asymmetric hydrogenation of maleic acid diesters and anhydrides
-
Asymmetric hydrogenation of maleic and fumaric acid derivatives with iridium catalysts based on N,P ligands provides an efficient route to chiral enantioenriched succinates. A new catalyst derived from a 2,6-difluorophenyl- substituted pyridine-phosphinite ligand was developed and enables the conversion of a wide range of 2-alkyl and 2-arylmaleic acid diesters into the corresponding succinates in high enantiomeric purity. Mixtures of cis/trans substrates can be hydrogenated in an enantioconvergent fashion with high enantioselectivity, and further enhances the scope of this transformation. The products are valuable chiral building blocks with a structural motif found in many bioactive compounds, such as metalloproteinase inhibitors. An attractive enantioselective route to 2-alkyl- and 2-aryl-substituted succinic acid derivatives is opened up by the asymmetric hydrogenation of maleic and fumaric acid derivatives, using the new catalyst [Ir(cod)L]BArF, derived from a 2,6-difluorophenyl-substituted pyridine-phosphinite ligand. The products are valuable chiral building blocks having a structural motif found in many bioactive compounds. cod=1,5-cyclooctadiene.
- Bernasconi, Maurizio,Mueller, Marc-Andre,Pfaltz, Andreas
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supporting information
p. 5385 - 5388
(2014/06/09)
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- Squaramide-catalyzed enantioselective Michael addition of masked acyl cyanides to substituted enones
-
Masked acyl cyanide (MAC) reagents are shown to be effective umpolung synthons for enantioselective Michael addition to substituted enones. The reactions are catalyzed by chiral squaramides and afford adducts in high yields (90-99%) and with excellent enantioselectivities (85-98%). The addition products are unmasked to produce dicyanohydrins that, upon treatment with a variety of nucleophiles, provide γ-keto acids, esters, and amides. The use of this umpolung synthon has enabled, in enantiomerically enriched form, the first total synthesis of the prenylated phenol (+)-fornicin C.
- Yang, Kin S.,Nibbs, Antoinette E.,Tuerkmen, Yunus E.,Rawal, Viresh H.
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supporting information
p. 16050 - 16053
(2013/11/19)
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- Steric effects on the stereochemistry of old yellow enzyme-mediated reductions of unsaturated diesters: Flipping of the substrate within the enzyme active site induced by structural modifications
-
The ene-reductase-mediated reduction of the carbon-carbon double bond of some alkyl 2- substituted butenedioates was investigated. The stereochemical outcome of the reaction was found to be influenced by steric effects. Ethyl and butyl citraconates were converted into the corresponding alkyl (R)-2-methylsuccinates with excellent enantioselectivity, whereas ethyl and butyl mesaconates were completely unreactive. Methyl 2-substituted fumarates were reduced to enantiomerically enriched methyl (S)-2-substituted succinates, whereas the (Z)-stereoisomers were left unreacted by enereductases. Labelling experiments were performed to investigate the mechanism of these bioreductions and explain their stereochemical outcome.
- Brenna, Elisabetta,Gatti, Francesco G.,Manfredi, Alessia,Monti, Daniela,Parmeggiani, Fabio
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p. 2859 - 2864
(2013/01/15)
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- Preparation of chiral 3-arylpyrrolidines via the enantioselective 1,4-addition of arylboronic acids to fumaric esters catalyzed by Rh(I)/chiral diene complexes
-
A highly efficient rhodium-catalyzed protocol for the preparation of 2-arylsuccinic esters and 3-arylpyrrolidines of high optical purity has been achieved. In the presence of 1 mol % of a chiral diene/Rh(I) catalyst, asymmetric addition of various arylbor
- Chung, Yu-Chiang,Janmanchi, Damodar,Wu, Hsyueh-Liang
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supporting information; experimental part
p. 2766 - 2769
(2012/07/17)
-
- Oxidative rearrangement of alkyl aryl/heteroaryl ketones by 1,2-aryl/heteroaryl shift using iodic acid
-
A method for synthesis of α-aryl/heteroaryl alkanoic acids involving oxidative rearrangement of alkyl aryl/heteroaryl ketones by 1,2-aryl/heteroaryl shift using iodic acid is described. ARKAT-USA, Inc.
- Huddar, Sameerana N.,Deshmukh, Swapnil S.,Akamanchi, Krishnacharya G.
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experimental part
p. 67 - 75
(2011/06/19)
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- One-step synthesis of chiral dimethyl 2-oxo-3-phenyl-glutarate in the asymmetric triple-carbonylation of styrene
-
The in situ preparation of the novel chiral catalyst system, which are composed of (S)-2,2′,6,6′-tetramethoxy- 4,4′- bis(diphenylphosphine)-3,3′-bipyridine ((S)-P-PHOS) and palladium 2,4-pentanedionate, have been described. These complexes were found to be effective in the asymmetric triple-carbonylation of styrene, reaching up to [α]D20 = +27o (c, 0.28, CH 2Cl2) for dimethyl 2-oxo-3-phenyl-glutarate using benzoquinone as oxidant, p-toluenesulfonic acid as co-catalyst, and methanol as solvent.
- Wang, Lailai,Zhang, Qinsheng,Cui, Yuming
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experimental part
p. 1143 - 1148
(2012/07/13)
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- Recyclable Pd(OAc)2/ligand/Al(OTf)3 catalyst for the homogeneous methoxycarbonylation and hydrocarboxylation reactions of phenylacetylene
-
The Pd-catalyzed methoxycarbonylation reaction of phenylacetylene was studied making use of various promoters, including aluminum triflate and several other acid-type promoters of this reaction. The influence of the ligand (bidentate-type ligands and monodentate analogues) was found to be determinative of the success of the reaction. The catalyst was found to be recyclable through 10 catalytic runs. The unique results when using BINAP, relating to the selectivity for the branched product and the stability of the catalyst produced, led to a study on the sulfonated analogue thereof, with the intention of performing hydrocarboxylation reactions to directly prepare the carboxylic acid. The product obtained accordingly may be varied between the methyl ester or its carboxylic acid equivalent, depending on the solvent medium and the ligand employed.
- Williams, D. Bradley G.,Shaw, Megan L.,Hughes, Tanya
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p. 4968 - 4973
(2011/11/05)
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- A thiourea-oxazoline library with axial chirality: Ligand synthesis and studies of the palladium-catalyzed enantioselective bis(methoxycarbonylation) of terminal olefins
-
We report herein the synthesis of novel chiral S,N-heterobidentate thiourea-oxazoline ligands and their application to palladium-catalyzed enantioselective bis(methoxycarbonylation)s of terminal olefins under mild conditions. Copper salts were found to play multiple roles in this reaction. Substituted 2- phenylsuccinates were obtained in >90% yield and up to 84% ee under optimized conditions.
- Gao, Ying-Xiang,Chang, Le,Shi, Hang,Liang, Bo,Wongkhan, Kittiya,Chaiyaveij, Duangduan,Batsanov, Andrei S.,Marder, Todd B.,Li, Chuang-Chuang,Yang, Zhen,Huanga, Yong
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supporting information; experimental part
p. 1955 - 1966
(2010/11/03)
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- Dicationic palladium(II)-spiro bis(isoxazoline) complex for highly enantioselective isotactic copolymerization of CO with styrene derivatives
-
The enantioseletive alternating copolymerization of CO with styrene derivatives catalyzed by a dicationic palladium(II) complex of tetra isopropyl-substituted spiro bis(isoxazoline) (i-Pr-SPRIX) is developed. This polymerization proceeded efficiently to p
- Bajracharya, Gan B.,Koranne, Priti S.,Tsujihara, Tetsuya,Takizawa, Shinobu,Onitsuka, Kiyotaka,Sasai, Hiroaki
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scheme or table
p. 310 - 314
(2009/07/18)
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- Electrochemical carboxylation of cinnamate esters in MeCN
-
Electrochemical carboxylation of cinnamate esters has been carried out by cathodic reduction of C{double bond, long}C bond in an undivided cell equipped with Mg sacrificial anode and using MeCN saturated with CO2 as solvent. The yields and the
- Wang, Huan,Zhang, Kai,Liu, Ying-Zi,Lin, Mei-Yu,Lu, Jia-Xing
-
p. 314 - 318
(2008/09/16)
-
- Oxidative rearrangements of arylalkanones with 1H-1-hydroxy-5-methyl-1,2,3-benziodoxathiole 3,3-dioxide, a 'green' analog of Koser's reagent
-
Previous methods for the conversion of arylalkanones to alkyl 2-arylesters by oxidative rearrangement utilized reagents which either produced toxic metal salts or halogenated organics as by-products. In this report, 1H-1-hydroxy-5-methyl-1,2,3-benziodoxathiole 3,3-dioxide (HMBI) is used to effect this useful transformation, where the reduced iodine reagent is water-soluble and readily recycled.
- Justik, Michael W.
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p. 3003 - 3007
(2008/02/06)
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- HETEROCYCLIC ARYLSULPHONES SUITABLE FOR TREATING DISORDERS THAT RESPOND TO MODULATION OF THE SEROTONIN 5HT6 RECEPTOR
-
The invention relates to compounds of the formula (I) wherein the variables have meanings given in the claims and the description. The invention also relates to the use of a compound of the formula (I) or a pharmaceutically acceptable salt thereof for pre
- -
-
Page/Page column 143; 158
(2008/06/13)
-
- HETEROCYCLIC COMPOUNDS SUITABLE FOR TREATING DISORDERS THAT RESPOND TO MODULATION OF THE DOPAMINE D3 RECEPTOR
-
The invention relates to compounds of the formula (I) wherein n is 0, 1 or 2; G is CH2 or CHR3; R1 is H, C,-C6-alkyl, C,-C6-alkyl substituted by C3-C6-cycloalkyl, Cl-C6-hydroxyalkyl, fluorinated C,-C6-alkyl, C3-C6-cycloalkyl, fluorinated C3-C6-cycloalkyl, C3-C6- alkenyl, fluorinated C3-C6-alkenyl, formyl, acetyl or propionyl; R2, R3 and R4 are, independently of each other, H, methyl, fluoromethyl, difluoromethyl, or trifluoromethyl; A is phenylene, pyridylene, pyrimidylene, pyrazinylene, pyridazinylene or thiophenylene, which can be substituted by one ore more substituents selected from halogen, methyl, methoxy and CF3; E is NR5 or CH2, wherein R5 is H or C1 -C3-alkyl; Ar is a cyclic radical selected from the group consisting of phenyl, a 5- or 6- -membered heteroaromatic radical comprising as ring members 1, 2 or 3 heteroatoms selected from N, O and S and a phenyl ring fused to a saturated or unsaturated 5- or 6-membered carbocyclic or heterocyclic ring, where the heterocyclic ring comprises as ring members 1, 2 or 3 heteroatoms selected from N, O and S and/or 1, 2 or 3 heteroatom-containing groups each independently selected from NR8, where R8 is H, C1-C4-alkyl, fluorinated C1-C4-alkyl, C1-C4-alkylcarbonyl or fluorinated C1-C4-alkylcarbonyl, and where the cyclic radical Ar may carry 1, 2 or 3 substituents Ra, wherein the variable Ra has the meanings given in the claims and in the description; and physiologically tolerated acid addition salts thereof. The invention also relates to the use of a compound of the formula I or a pharmaceutically acceptable salt thereof for preparing a pharmaceutical composition for the treatment of a medical disorder susceptible to treatment with a dopamine D3 receptor ligand.
- -
-
Page/Page column 107-108
(2010/11/08)
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- N-vinyl-2-oxazolidinones: Efficient chiral dienophiles for the [4 + 2]-based de novo synthesis of new N-2-deoxyglycosides
-
Under smooth Eu(fod)3-catalyzed conditions, the inverse-electron demand hetero-Diels-Alder reactions between enantiopure N-vinyl-2-oxazolidinones 1a-f and representative β,γ-unsaturated α-ketoesters proceed with a high degree of endo and facial
- Gaulon, Catherine,Dhal, Robert,Chapin, Teddy,Maisonneuve, Vincent,Dujardin, Gilles
-
p. 4192 - 4202
(2007/10/03)
-
- Room-temperature ionic liquids as new solvents for organic electrosynthesis. The first examples of direct or nickel-catalysed electroreductive coupling involving organic halides
-
Direct or Ni-catalysed electroreductive homocouplings of organic halides and couplings of organic halides with activated olefins are efficiently conducted by constant current electrolyses in an undivided cell in room-temperature ionic liquids as the solvent-electrolyte media.
- Barhdadi, Rachid,Courtinard, Coralie,Nedelec, Jean Yves,Troupel, Michel
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p. 1434 - 1435
(2007/10/03)
-
- Novel one-pot vicinal double C-acylation of styrenes and methacrylates by electroreduction
-
Electroreduction of styrenes or alkyl methacrylates in the presence of aliphatic acid anhydrides or N-acylimidazoles with an undivided cell equipped with zinc electrodes as the anode and the cathode brought about novel one-pot vicinal double C-acylation to afford the corresponding 1,4-diketones in satisfactory yields.
- Yamamoto, Yoshimasa,Maekawa, Hirofumi,Goda, Satoshi,Nishiguchi, Ikuzo
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p. 2755 - 2758
(2007/10/03)
-
- Oxidative carbomethoxylation of alkenes using a Pd(II)/molybdovanadophosphate (NPMoV) system under carbon monoxide and air
-
Oxidative carbomethoxylation of cyclopentene (1) under carbon monoxide and air by the use of a catalytic amount of Pd(OAc)2 and molybdovanadophosphate (NPMoV) led to dimethyl cis-1,2-cyclopentanedicarboxylate (2) and dimethyl cis-1,3-cyclopentanedicarboxylate (3) in good yields. Total yields of 2 and 3 were found to be improved by adding a small amount of NH4Cl. Several alkenes were similarly converted into the corresponding dimethyl dicarboxylates. The role of Cl- in the present catalytic system is suggested.
- Yokota, Takahiro,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 5005 - 5008
(2007/10/03)
-
- Nickel-catalyzed electrochemical arylation of activated olefins
-
Nickel-catalyzed electrochemical conjugate additions of substituted aryl bromides to activated olefins under recently optimized reaction conditions are reported. Good to high yields were obtained, whatever the nature of substituents in the meta- and para-positions of the benzene ring. In the ortho-substituted series, yields were good with electron-donating substituents, but low with electron-withdrawing groups. The activation of aryl chlorides and the sequential functionalization of aryl dihalides were also investigated.
- Condon, Sylvie,Dupre, Daniel,Falgayrac, Gilles,Nedelec, Jean-Yves
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p. 105 - 111
(2007/10/03)
-
- Bis-alkoxycarbonylation of styrene by pyridinimine palladium catalysts
-
Pyridinimine-modified Pd(II) complexes of general formulae (N-N′)Pd(Y)2 catalyze the methoxycarbonylation of styrene to give dimethyl phenylsuccinate as the largely major product [N-N′ = py-2-C(R) = N(2,6-R′C6H3), R = H, Me; R′ = Me, i-Pr; 6-Mepy-2-C(H)=N[2,6-(i-Pr)2C6H3]; py-2-C(H)=N(C6H5); Y = acetate, trifluoroacetate]. The influence of various catalytic parameters on the overall conversion of styrene to carbonylated products and on the product selectivity has been studied by systematically varying the type of palladium initiator, the concentrations of organic oxidant (1,4-benzoquinone) and protic acid (p-toluenesulfonic acid), and the CO pressure. By an appropriate choice of the structure of the pyridinimine ligand and of the reaction parameters, turn-over numbers as high as 96 and selectivities in dimethyl phenylsuccinate as high as 98% were obtained. In particular, the overall conversion of styrene is controlled by the steric properties of the alkyl substituents on the imine aryl group, while the nature of the substituent (H or Me) on the imine carbon influences the selectivity. The addition of 2 equivalents of TsOH to the catalytic mixtures generally increased the styrene conversion but lowered the selectivity in dimethyl phenylsuccinate due to greater production of methyl 3,6-diphenyl-4-oxohexanoate. Further additions of TsOH (up to 6 equivalents) resulted in better selectivities and lower conversions for all precursors.
- Bianchini, Claudio,Hon, Man Lee,Mantovani, Giuseppe,Meli, Andrea,Oberhauser, Werner
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p. 387 - 397
(2007/10/03)
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- Rhodium-catalyzed conjugated addition of aryllead reagents to α,β-unsaturated carbonyl compounds in air and water
-
In the presence of a rhodium catalyst, α,β-unsaturated esters and ketones (1a-f) react with phenyltrimethyllead 2 in aqueous media and under an air atmosphere to give the corresponding conjugated addition products (3a-e) in high yields.
- Ding,Chen,Wang,Li
-
p. 1470 - 1472
(2007/10/03)
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- Novel diphosphine-modified palladium catalysts for oxidative carbonylation of styrene to methyl cinnamate
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The oxidative carbonylation of styrene has been achieved in MeOH with known and new palladium(II) catalysts of general formulae [Pd(P-P)(MeCN)2][PF6]2, [Pd(P-P)(bipy)][PF6]2, Pd(P-P)(OAc)2, [Pd2(cyclo-tetraphos)(MeCN)4]-[PF6]4 , [Pd2(cyclo-tetraphos)(bipy)2][PF6]4, Pd2(cyclo-tetraphos)(OAc)4 (P-P = 1,2-bis(diphenylphosphino)ethane), meso-2,3-bis(diphenylphosphino)butane or rac-2,3-bis(diphenylphosphino)butane; cyclo-tetraphos = cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane; bipy = 2,2′-bipyridine; OAc = acetate). The influence of various catalytic parameters on the overall conversion of styrene into carbonylated products and on the product selectivity has been studied by systematically varying the type of palladium initiator, the concentrations of organic oxidant (1,4-benzoquinone) and protic acid (p-toluenesulfonic acid), and the CO pressure. This investigation has allowed a partial optimization of the process so as to obtain the largely predominant formation of either methyl cinnamate (highest selectivity 99%) or dimethyl phenylsuccinate (highest selectivity 88%).
- Bianchini, Claudio,Mantovani, Giuseppe,Meli, Andrea,Oberhauser, Werner,Brueggeller, Peter,Stampfl, Thomas
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p. 690 - 698
(2007/10/03)
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- Asymmetric bis(alkoxycarbonylation) reaction of terminal olefins catalyzed by palladium in the presence of copper(I) triflate and a chiral bioxazoline ligand
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A palladium-catalyzed asymmetric bis(alkoxycarbonylation) reaction of terminal olefins in the presence of copper(I) triflate was achieved by using a chiral bioxazoline ligand, (4S,4′S)-4,4′-dibenzyl-4,4′,5,5′-tetrahydro- 2,2′-bioxazole, under normal press
- Takeuchi,Ukaji,Inomata
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p. 955 - 958
(2007/10/03)
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- Catalyst for bisalkoxycarbonylation of olefins, and method for production of succinate derivatives
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A catalyst for the bisalkoxycarbonylation of olefins comprising a noble metal compound and a phosphine chalcogenide of the following formula (1): wherein each of R1, R2 and R3 is, independently, an alkyl group or an aryl group each of which may have a substituent, and A is a Group 16 element of the Periodic Table; and R1, R2 or R3 may be combined, directly or through a bridging group, with one another where the groups to be combined may be attached either to an identical phosphorus atom or to different phosphorus atoms. Element A includes oxygen, sulfur and selenium atoms. The noble metal compound includes palladium(II) halides and other palladium compounds. The catalyst may further include a copper(I) halide or other copper compound as a co-catalyst. The use of this catalyst can provide the bisalkoxycarbonylation of olefins with efficiency.
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- Asymmetric conjugate 1,4-addition of arylboronic acids to α,β-unsaturated esters catalyzed by rhodium(I)/(S)-binap
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Arylboronic acids underwent the conjugate 1,4-addition to α,β-unsaturated esters to give β-aryl esters in high yields in the presence of a rhodium(I) catalyst. The addition of arylboronic acids to isopropyl crotonate resulted in high yields and high enantioselectivity exceeding 90% ee in the presence of 3 mol % of Rh(acac)(C2H4)2 and (S)-binap at 100 °C. The rhodium/(S)-binap complex provided (R)-3-phenylbutanoate in the addition of phenylboronic acid to benzyl crotonate. The effects on the enantioselectivity of chiral phosphine ligands, rhodium precursors, and substituents on α,β-unsaturated esters are discussed, as well as the mechanistic aspect of the catalytic cycle.
- Sakuma, Satoshi,Sakai, Masaaki,Itooka, Ryoh,Miyaura, Noria
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p. 5951 - 5955
(2007/10/03)
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- Synthetic application of poly[styrene(iodoso diacetate)]
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Poly[styrene(iodoso diacetate)] is sufficiently reactive to effect the iodination of aromatics and oxidative 1,2-aryl migration of alkyl aryl ketones as (diacetoxyiodo)benzene, and can be regenerated and reused for the same reactions.
- Togo, Hideo,Nogami, Genki,Yokoyama, Masataka
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p. 534 - 536
(2007/10/03)
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- Phosphine sulfides: Novel effective ligands for the palladium-catalyzed bisalkoxycarbonylation of olefins
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Phosphine sulfides were found to be effective as a ligand in the palladium(II)-catalyzed bisalkoxycarbonylation of olefins. Aromatic olefins and vinylsilanes were converted into the corresponding succinates in high yields under mild conditions. Enantiosel
- Hayashi, Minoru,Takezaki, Hiroshi,Hashimoto, Yukihiko,Takaoki, Kazuo,Saigo, Kazuhiko
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p. 7529 - 7532
(2007/10/03)
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- Combined oxidative and reductive carbonylation of terminal alkynes with palladium iodide-thiourea catalysts
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Oxidative carbonylation of alkynes can be carried out catalytically in the absence of added oxidants if it is coupled with a reductive carbonylation process at the expense of the same alkyne involved in the oxidative process.Maleic esters (from oxidative carbonylation) and unsaturated lactones (from reductive carbonylation) are the main products formed under the catalytic action of palladium iodide complexes with thiourea (tu).A complex, formally corresponding to the ionic formula I, allows the reaction of alkylacetylenes at room temperature and atmospheric pressure.With activated alkynes such as phenylacetylene, or with alkynes containing coordinating groups, other palladium complexes with two or four molecules of thiourea are also active, although to a lesser extent.Identification of the organic by-products gives a hint of the mechanism by which coupling of oxidative and reductive carbonylation occurs.Keywords: Palladium; Alkynes; Oxidative carbonylation; Reductive carbonylation; Catalysis, Thiourea
- Gabriele, Bartolo,Salerno, Giuseppe,Costa, Mirco,Chiusoli, Gian Paolo
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- Mechanistic investigations of palladium-catalysed single and double carbonylation of aryl and vinyl halides by methyl formate
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The palladium-catalysed methoxycarbonylation of PhCH=CHBr in the presence of HCO2CH3, NEt3 and CO has been investigated and compared to that of PhI.Methyl cinnamate was the only product observed.Model reaction studies were conducted on the possible intermediates (1), (2a), and (3).The results suggest that the high alcoholysis rate of complex 2a is respondible for the lack of double carbonylation product from PhCH=CHBr.NMR studies of the catalytic systems in the presence of HCO2CH3 revealed the presence of the suggested aroylpalladium complexes (2a and 3) in conjunction with (4).Both stoichiometric and catalytic experiments indicated that complex 4 is a possible intermediate in the formation of both simple esters and α-keto esters, but that the latter arise mainly from classical aroylpalladium(II) complexes.The activation pathway of HCO2CH3 has been studied and a dramatic influence of CH3OH concentration in the reaction medium has been found.These results suggest that CH3OH arising from smooth decarbonylation of HCO2CH3 under the reaction conditions is the main alkoxy-transfer agent.Key words: Palladium; Catalysis; Carbonylation
- Carpentier, Jean-Francois,Castanet, Yves,Mortreux, Andre,Petit, Francis
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- Reductive Arylation of Maleic and Fumaric Acid Derivatives by Arenediazonium and Titanium(III) Salts
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The titanium(III)-induced decomposition of substituted benzenediazonium salts in the presence of maleic and fumaric acids, alkyl esters, amides, and nitriles gives the corresponding arylsuccinic acid derivatives.
- Citterio, Attilio,Cominelli, Alberto,Bonavoglia, Francesco
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p. 308 - 309
(2007/10/02)
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- Synthesis of 2-Arylsuccinates by Oxidative 1,2-Aryl Migration of 3-Aroylpropionic Acids or 5-Arylfuran-2(3H)-ones with Thallium(III) Nitrate
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Treatment of 3-aroylpropionic acids (1) with thallium(III) nitrate causes smooth 1,2-aryl migration to give dimethyl 2-arylsuccinates (2) in good yields.Similar transformation of 5-arylfuran-2(3H)-ones (3) with thallium(III) nitrate to 1-methyl 2-arylsucc
- Tamura, Yasumitsu,Shirouchi, Yoshiaki,Minamikawa, Jun-ichi,Haruta, Jun-ichi
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p. 551 - 556
(2007/10/02)
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- Electrochemical Reductive Carboxylation: Reduction of Unsaturated Compounds in the Presence of Methyl Chloroformate
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Mono- and dicarboxylated derivatives have been obtained by electroreduction of various unsaturated compounds in acetonitrile at a mercury-pool cathode in the presence of methyl chloroformate.Unsaturated compounds included activated olefins, ketones, aromatic Schiff bases, nitro compounds, and nitrogen heterocycles.The distribution of the products and their yields depend on the nature of the supporting electrolyte (Et4NClO4 or LiClO4).Reduction mechanisms accounting for the nature of the reduction products are proposed on the basis of voltammetric and coulometric data.In some cases it is possible to obtain the kinetic parameters.
- Armand, Joseph,Bellec, Christian,Boulares, Line,Pinson, Jean
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p. 2847 - 2853
(2007/10/02)
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