- Enantioselective Conjugate Addition of Stabilized Arylzinc Iodide to Enones: an Improved Protocol of the Hayashi Reaction
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Stabilised arylzinc iodide, prepared by direct insertion of zinc into aryl iodides, were used as nucleophiles in the Hayashi Rh-catalysed enantioselective conjugate addition to enones. The reaction conditions were optimized in the addition of phenylzinc i
- Casotti, Gianluca,Rositano, Vincenzo,Iuliano, Anna
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p. 1126 - 1131
(2020/12/17)
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- Synthesis of multinuclear Rh(I) complexes bearing triazolylidenes and their application in C-C and c-Si bond forming reactions
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Multidentate carbene ligands are valuable frameworks for the preparation of carbene complexes displaying higher nuclearity. In the present work, we report the synthesis of a series of mono- to tetra-[Rh(COD)I] complexes (3a- d) supported by mesoionic triazol-5-ylidenes. The general synthetic procedure involves the one step reaction of the appropriate triazolium (2a-d) salt in the presence of KHMDS and stoiquiometric amounts of the rhodium(I) precursor. Treatment of complexes 3a-d with an excess of carbon monoxide allows for the quantitative preparation of complexes 4a-d featuring a [Rh(CO)2I] fragment used for the detemination of the donor properties of the new triazolylidene ligands. All complexes have been fully characterized by means of 1H and 13C NMR spectroscopy, melting point, elemental analysis, and in the case of complex 3a, by X-ray crystallography. Comparison of the catalytic activity of the new rhodium complexes in C-C and C-Si bond forming processes demonstrate the enhanced performance of the tetranuclear species suggesting the possibility of strong cooperative effects in these multinuclear complexes.
- Mendoza-Espinosa, Daniel,Rendón-Nava, David,Vásquez-Pérez, Jose M.,Sandoval-Chávez, Cesar I.,Alvarez-Hernández, Alejandro
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supporting information
p. 3961 - 3971
(2020/12/01)
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- The synthesis method of one-carbon ring expansion of cycloketone dericatives from β-selenyl cycloketone dericatives
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The present invention relates to a method for preparing a cyclic ketone derivative with an increased carbon number by performing a ring expansion reaction of a β-selenyl cyclic ketone derivative. The present invention was first developed by performing the
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Paragraph 0041; 0044-0048; 0050-0054
(2020/09/08)
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- Rh-catalyzed 1,4-addition reactions of arylboronic acids accelerated by co-immobilized tertiary amine in silica mesopores
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Mesoporous silica-supported Rh complex catalysts were prepared by simple silane-coupling, followed by complexation, and characterized by FT-IR, SEM, Rh K-edge XAFS, and elemental analysis. Local structures of the Rh complexes in each sample were almost similar to those of a nonporous silica-supported diaminorhodium complex. Co-immobilization of a tertiary amine on the same silica surface induced slight changes to the Rh complex structure in the case of the support with smaller pores. The prepared catalysts showed high activity for the 1,4-addition reaction of phenylboronic acids. Co-immobilization of the tertiary amine increased the reaction rate by more than 7-fold, with turnover number of nearly 8500. The catalytic performance achieved with this novel system is with much higher than that reported previously with a nonporous silica-supported catalyst. The mesoporous silica-supported Rh complex-tertiary amine showed a wide substrate scope, including unsaturated ketones and nitriles. This co-immobilized tertiary amine may activate phenylboronic acid to enhance its reactivity in the transmetalation step with Rh-OH species.
- Motokura, Ken,Hashiguchi, Kohei,Maeda, Kyogo,Nambo, Masayuki,Manaka, Yuichi,Chun, Wang-Jae
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- Anthranilamide (aam)-substituted arylboranes in direct carbon-carbon bond-forming reactions
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Anthranilamide (aam)-substituted arylboranes, which were reported to serve as masked boranes in the Suzuki-Miyaura coupling, have been found to be directly cross-coupled just by use of an aqueous medium. The excellent stability of 2-pyridyl-B(aam) toward protodeborylation allowed their smooth cross-coupling.
- Kamio, Shintaro,Kageyuki, Ikuo,Osaka, Itaru,Yoshida, Hiroto
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supporting information
p. 2624 - 2627
(2019/03/05)
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- Electrochemical Radical Selenylation/1,2-Carbon Migration and Dowd-Beckwith-Type Ring-Expansion Sequences of Alkenylcyclobutanols
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Electrochemical oxidative radical selenylation/1,2-carbon migration and Dowd-Beckwith-type ring-expansion sequences of alkenylcyclobutanols were developed in this study. This approach is environmentally benign and uses shelf-stable diselenides as selenium
- Kim, Yeon Joo,Kim, Dae Young
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p. 1021 - 1025
(2019/02/14)
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- Synthesis of β-Selenylated Cyclopentanones via Photoredox-Catalyzed Selenylation/Ring-Expansion Cascades of Alkenyl Cyclobutanols
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A photoredox strategy to access β-selenated cyclic ketone derivatives through the coupling reaction of 1-(1-arylvinyl)cyclobutanols with diselenides under blue LED irradiation and an air atmosphere was developed. This reaction employs the easily accessibl
- Jung, Hye Im,Kim, Dae Young
-
supporting information
p. 1361 - 1365
(2019/06/19)
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- Phosphine ligand compounds based on tetramethylspirobiindane skeleton, intermediate of compounds, and preparation method and application of compounds
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The invention discloses phosphine ligand compounds based on a tetramethylspirobiindane skeleton, an intermediate of the compounds, and a preparation method and application of the compounds. The phosphine ligand compounds are compounds having a structure r
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-
Paragraph 0166; 0167; 0168
(2018/11/03)
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- Synthesis of Cyclohexanones through a Catalytic Cationic Cyclization of Alkynols or Enynes
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A novel procedure for the synthesis of cyclohexanones from alkynol or enyne derivatives through a cationic cyclization has been developed. The key points to obtain the six-membered ring derivatives are the use of starting materials containing a terminal alkyne, the use of tetrafluoroboric acid as a promoter of the cationic cyclization, and the appropriate selection of 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP) as solvent. This strategy can be extended to the biomimetic cationic cyclization of several terpene-derived polyenynes.
- Alonso, Pedro,Fontaneda, Raquel,Pardo, Pilar,Fa?anás, Francisco J.,Rodríguez, Félix
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supporting information
p. 1659 - 1662
(2018/03/23)
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- Palladium-catalyzed redox cascade for direct β-arylation of ketones
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Herein we report a full article about the detailed design and development of two palladium-catalyzed redox cascade methods that enable direct β-arylation of ketones. Palladium-catalyzed ketone dehydrogenation, aryl-X bond activation and conjugate addition were merged into a redox-neutral catalytic cycle. Non-metal-based aryl electrophiles were used as both the oxidant and the aryl source. The β-arylation with aryl iodides was achieved site-selectively with Pd(TFA)2/P(i-Pr)3 as the precatalyst and AgTFA as the iodide scavenger. Both cyclic and linear ketones can react to give β-aryl ketones with excellent functional group tolerance. The β-arylation with diaryliodonium salts was realized without stoichiometric heavy metal additives, and proved to be redox-neutral. A wider substrate scope regarding aryl groups and ketones was obtained for the arylation with diaryliodonium salts, and the possible involvement of palladium nanoparticles as the active catalyst was examined and discussed.
- Huang, Zhongxing,Dong, Guangbin
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supporting information
p. 3253 - 3265
(2018/05/04)
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- Palladium-Catalyzed Direct β-C?H Arylation of Ketones with Arylboronic Acids in Water
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A palladium-catalyzed direct β-C?H arylation of ketones was developed under mild conditions in water, featuring commercially available arylboronic acids as nucleophilic aryl sources and o-iodoxybenzoic acid as the oxidant. The method provides a concise route to access β-arylated ketones. Preliminary studies indicated that direct asymmetric β-C?H arylation of ketones could be achieved by this strategy. (Figure presented.).
- Hu, Xiaoyun,Yang, Xiaobo,Dai, Xi-Jie,Li, Chao-Jun
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supporting information
p. 2402 - 2406
(2017/07/22)
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- Rh-catalyzed 1,4-addition of triallyl(aryl)silanes to α,β-unsaturated carbonyl compounds
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Rh-catalyzed 1,4-addition of triallyl(aryl)silane to α,β-unsaturated carbonyl compounds was developed. Triallyl(aryl)silanes were used as air- and moisture-stable silicon nucleophiles. Allylsilanes were converted to silanols in situ and underwent transmetalation. This method can accept a wide range of functionalized triallyl(aryl)silane and α,β-unsaturated carbonyl compounds.
- Kamei, Toshiyuki,Uryu, Mizuho,Shimada, Toyoshi
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supporting information
p. 1622 - 1624
(2018/03/22)
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- 2-allyl-1-oxo-2, 3-dihydro-1, 2-benzisothiazole
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The invention discloses chiral 2-allyl-1-oxo-2, 3-dihydro-1, 2-benzisothiazole and its preparation method and use. The chiral 2-allyl-1-oxo-2, 3-dihydro-1, 2-benzisothiazole is a racemate or an optical isomer shown in the formula I and is characterized in
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-
Paragraph 0033; 0037
(2017/02/02)
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- DIRECT B-ARYLATION OF CARBONYL COMPOUNDS
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Disclosed is a method for the β-C—H H functionalization of carbonyl compounds that is both selective and broadly applicable. The methods provide direct β-arylation of carbonyl compound with a diverse array of aryl or heteroaryl halides, aryl or heteroryl tosylate, aryl or heteroaryl triflates, or diaryliodonium salts, by palladium catalysis in the presence of a ligand and promoter.
- -
-
Paragraph 0123-0125; 128
(2016/09/12)
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- Heterogeneous double-activation catalysis: Rh complex and tertiary amine on the same solid surface for the 1,4-addition reaction of aryl- and alkylboronic acids
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Double-activation catalysis by a rhodium complex/tertiary amine catalyst for the 1,4-addition of organoboronic acids was investigated. A rhodium complex and a tertiary amine were co-immobilized on the same silica surface by silane-coupling reactions follo
- Noda, Hiroto,Motokura, Ken,Chun, Wang-Jae,Miyaji, Akimitsu,Yamaguchi, Sho,Baba, Toshihide
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p. 2714 - 2727
(2015/05/27)
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- Palladium-catalyzed direct β-arylation of ketones with diaryliodonium salts: A stoichiometric heavy metal-free and user-friendly approach
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We herein report a new protocol for the Pd-catalyzed β-arylation of ketones without stoichiometric heavy metals. Widely accessible diaryliodonium salts are used as both the oxidant and aryl source. This tandem redox catalysis merges ketone dehydrogenation and conjugate addition without an additional oxidant or reductant. This transformation features the use of a unique bis-N-tosylsulfilimine ligand and the combination of potassium trifluoroacetate/trifluoroacetic acid to maintain an appropriate acidity of the reaction medium. The reaction tolerates both air and moisture, and shows a broad substrate scope. Kinetics studies, along with filtration and poisoning tests, support the involvement of palladium nanoparticles in the catalysis.
- Huang, Zhongxing,Sam, Quynh P.,Dong, Guangbin
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p. 5491 - 5498
(2015/09/28)
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- Novel rhodium and iridium complexes coordinated to C3-symmetric tris-NHC ligands based on a 1,3,5-triphenylbenzene core. Electronic and catalytic properties
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A series of novel tris-azolium salt precursors based on 1,3,5-triphenylbenzene have been prepared. These salts exhibit fluorescence emission in the 320-420 nm region. The coordination of these salts to [MCl(COD)]2 (M = Rh, Ir) was carried out in the presence of KHMDS and allowed the formation of the corresponding tris-NHC complexes of Rh and Ir in high yield. The electronic properties of the new complexes were analyzed by means of cyclic voltammetry and IR spectroscopy of the related carbonylated species. The catalytic activity of the trirhodium complex toward the addition of arylboronic acids to cyclohexen-2-one has been evaluated and compared to the activity shown by a related monometallic complex.
- Mejuto, Carmen,Guisado-Barrios, Gregorio,Peris, Eduardo
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p. 3205 - 3211
(2014/07/08)
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- 1,4-Addition of aryl boronic acids to α,β-unsaturated ketones catalyzed by a CCC-NHC pincer rhodium complex
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An air- and water-stable CCC-NHC pincer Rh complex catalyzed the 1,4-addition of aryl boronic acids to α,β-unsaturated ketones and aldehydes. This bench top method proceeds in eco-friendly solvents including methanol and water. The scope of boronic acids was expanded to include heterocyclic examples.
- Reilly, Sean W.,Box, Hannah K.,Kuchenbeiser, Glenn R.,Rubio, Ramel J.,Letko, Christopher S.,Cousineau, Kandarpa D.,Hollis, T. Keith
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supporting information
p. 6738 - 6742
(2014/12/11)
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- Efficient 1,4-addition of enones and boronic acids catalyzed by a Ni-Zn hydroxyl double salt-intercalated anionic rhodium(III) complex
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Intercalation of an in situ prepared [Rh(OH)6]3- complex into an anion exchangeable Ni-Zn layered hydroxy double salt (Rh/NiZn) was demonstrated. The resulting Rh/NiZn effectively catalyzed the 1,4-addition of diverse enones and phenylboronic acids to their corresponding β-substituted carbonyl compounds. In the case of 2-cyclohexen-1-one and phenylboronic acid, a turnover frequency (TOF) of 920 h-1 based on Rh was achieved. The [Rh(OH)6]3- complex maintained its original monomeric trivalent state within the NiZn interlayer following catalysis, attributable to a strong electrostatic interaction between the NiZn host and anionic Rh(III) complex.
- Hara, Takayoshi,Fujita, Nozomi,Ichikuni, Nobuyuki,Wilson, Karen,Lee, Adam F.,Shimazu, Shogo
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p. 4040 - 4046
(2015/02/19)
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- Catalytic direct β-arylation of simple ketones with aryl iodides
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Herein we report a direct β-arylation of simple ketones with widely available aryl iodides, combining palladium-catalyzed ketone oxidation, aryl-halide activation, and conjugate addition through a single catalytic cycle. Simple cyclic ketones with different ring-sizes, as well as acyclic ketones, can be directly arylated at the β-position with complete site-selectivity and excellent functional group tolerance.
- Huang, Zhongxing,Dong, Guangbin
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p. 17747 - 17750
(2014/01/06)
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- Rhodium(I)-catalyzed arylation of β-chloro ketones and related derivatives through domino dehydrochlorination/conjugate addition
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Highly efficient arylations of β-chloro ketones and their ester and amide derivatives were achieved by means of domino dehydrochlorination/Rh(I)- catalyzed conjugate addition. In situ generated vinyl ketones and their analogues were identified as the reaction intermediates. The present synthetic protocol provides a concise route to (chiral) β-aryl ketones, esters, and amides. Copyright
- Jiang, Quanbin,Guo, Tenglong,Wang, Qingfu,Wu, Ping,Yu, Zhengkun
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supporting information
p. 1874 - 1880
(2013/07/19)
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- Palladium-catalyzed desulfitative conjugate addition of aryl sulfinic acids and direct ESI-MS for mechanistic studies
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A new and efficient method for palladium(II) catalytic desulfitative conjugate addition of arylsulfinic acids with α,β-unsaturated carbonyl compound has been developed. The key reacting intermediates including aryl Pd(II) sulfinic intermediate, aryl Pd(II), and C=O-Pd complexes were captured by ESI-MS/MS, which provide new experimental evidence for the understanding of addition mechanism.
- Wang, Huifeng,Li, Yaming,Zhang, Rong,Jin, Kun,Zhao, Defeng,Duan, Chunying
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supporting information; experimental part
p. 4849 - 4853
(2012/07/02)
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- Rhodium-grafted hydrotalcite catalyst for heterogeneous 1,4-addition reaction of organoboron reagents to electron deficient olefins
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A rhodium-grafted hydrotalcite (Rh/HT) was prepared by the treatment of a Mg-Al mixed hydroxide (hydrotalcite, HT) with an aqueous RhCl 3·nH2O solution. The formation of the Rh III species on the HT surface was confirmed by X-ray absorption fine structure spectroscopy. The Rh/HT catalyst was demonstrated to effectively promote the 1,4-addition reaction of organoboron reagents to electron-deficient olefins in both organic and aqueous solvents. The strong surface basicity of HT facilitates the formation of a Rh-OH species, which possesses high nucleophilicity, leading to an efficient transmetalation with organoboron reagents. This catalyst system is also applicable in the one-pot three-component synthesis of 2-cyano-3,3-diphenyl propionate due to the bifunctionality of the Rh/HT surface.
- Motokura, Ken,Hashimoto, Norifumi,Hara, Takayoshi,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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experimental part
p. 2416 - 2422
(2011/10/13)
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- N-heterocyclic carbene-rhodium(I) complexes derived from proline for the 1,4-conjugate addition of arylboronic acids to enones in neat water
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N-Heterocyclic carbene-rhodium(I) complexes derived from N-benzyl substituted proline have been successfully synthesized and were found to be efficient catalysts for the 1,4-conjugate addition of arylboronic acids to enones in neat water at 40 °C. Under the optimal reaction conditions, all reactions gave the addition products in good to high yields.
- Tang, Yi-Qiang,Lv, Huan,He, Xiao-Na,Lu, Jian-Mei,Shao, Li-Xiong
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experimental part
p. 705 - 708
(2012/01/07)
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- PH-Dependent conjugate addition of arylboronic acids to α,β-unsaturated enones catalyzed by a reusable palladium(II)/cationic 2,2'-bipyridyl system in water under air
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A reusable Pd(NH3)2Cl2/cationic 2,2'-bipyridyl system for the catalysis of the conjugate addition of arylboronic acids to α,β-unsaturated enones in water under air was developed. Addition of arylboronic acids to both cyclic and acyclic enones progressed smoothly, providing the products in good to high yields, the best result being obtained when HBF4 was used to adjust the pH value to 1.0. After the reaction, the residual aqueous solution could be reused several times,making the reaction greener and reducing wastage of precious metals. Copyright
- Huang, Shao-Hsien,Wu, Tzu-Min,Tsai, Fu-Yu
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experimental part
p. 619 - 624
(2010/11/04)
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- Addition reaction of arylboronic acids to aldehydes and α,β-unsaturated carbonyl compounds catalyzed by conventional palladium complexes in the presence of chloroform
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Arylboronic acids react with aldehydes and α,β-unsaturated carbonyl compounds in the presence of a base and a catalytic amount of a palladium(0) complex with chloroform, affording the corresponding addition products in good yields, and chiral benzhydrol was obtained with up to 43% e.e. using (S,S)-bppm as a ligand. General palladium complexes have no catalytic activity without chloroform. Because chloroform is essential for this reaction, these reactions would be promoted by dichloromethylpalladium(II) species.
- Yamamoto, Tetsuya,Iizuka, Michiko,Takenaka, Hiroto,Ohta, Tetsuo,Ito, Yoshihiko
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experimental part
p. 1325 - 1332
(2009/09/28)
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- The synthesis and catalytic activity of the iridium(I) hydroquinone complex [(H2Q)Ir(COD)]+
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The η6-hydroquinone iridium complex [(η6-H2Q)Ir(COD)]BF4 undergoes facile double deprotonation to the η4-quinone anionic analogue. The latter has been shown to be the first example of an iridium compl
- Kim, Sang Bok,Cai, Chen,Faust, Marcus D.,Trenkle, William C.,Sweigart, Dwight A.
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experimental part
p. 52 - 56
(2009/04/10)
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- Platinum-catalyzed 1,4-addition of arylboronic acids to β-substituted α,β-unsaturated ketones
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Platinum salts represented by K2PtCl4 were found to catalyze the 1,4-addition of arylboronic acids to β-substituted α,β-unsaturated ketones to give high yields of β-arylated ketones. The reaction is completed in 1h in the presence of 1 mol % of the catalyst in dioxane/H2O at 70 °C. Copyright
- Hayashi, Tamio,Sasaki, Keigo
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p. 842 - 843
(2008/12/22)
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- Rhodium quinonoid catalysts
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In accordance with one aspect of the invention a rhodium quinonoid catalyst is disclosed.
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Page/Page column 9; 10; 13
(2008/06/13)
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- Method of using rhodium quinonoid catalysts
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In accordance with aspects of the invention methods of using rhodium hydroquinone catalysts for the conjugate addition of boronic acids are disclosed.
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Page/Page column 13; 14
(2008/06/13)
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- Palladium(II)-catalyzed conjugate addition of arylsiloxanes in water
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Equation Presented Palladium-phosphinous acids catalyze the conjugate addition of arylsiloxanes to a wide range of α.β-unsaturated substrates in water microwave-assisted procedure is described that uses 5 mol % of POPd1 to afford /-substituted ketones, aldehydes, esters, nitriles, an nitroalkanes in 83% to 96% yield within 4 h. This method eliminates the need for stoichiometric additives and an excess of arylsiloxane, an does not require an inert atmosphere.
- Lerebours, Rachel,Wolf, Christian
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p. 2737 - 2740
(2008/02/07)
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- Palladium catalyzed conjugate 1,4-addition of organoboronic acids to α,β-unsaturated ketones
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1,4-Addition of arylboronic acids to α,β-unsaturated ketones was smoothly catalyzed by palladium(0) phosphine complexes with chloroform in the presence of base. It is remarked that the palladium(0) complexes have no catalytic activity in the absence of chloroform. The reaction proceeded without β-hydride elimination. Copyright
- Yamamoto, Tetsuya,Iizuka, Michiko,Ohta, Tetsuo,Ito, Yoshihiko
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p. 198 - 199
(2007/10/03)
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- A rhodium-grafted hydrotalcite as a highly efficient heterogeneous catalyst for 1,4-addition of organoboron reagents to α,β-unsaturated carbonyl compounds
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Treatment of a hydrotalcite with an aqueous solution of rhodium trichloride results in a Rh-grafted hydrotalcite (Rh/HT) with monomeric Rh species on the surface, which successfully promoted 1,4-addition of organoboron reagents to α,β-unsaturated carbonyl compounds. Furthermore, this catalyst was reusable and was found to be applicable to a one-pot synthesis of 3,3-diarylnitrile.
- Fujita, Noriaki,Motokura, Ken,Mori, Kohsuke,Mizugaki, Tomoo,Ebitani, Kohki,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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p. 5083 - 5087
(2007/10/03)
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- Palladium-bipyridine catalyzed conjugate addition of arylboronic acids to α,β-unsaturated carbonyl compounds in aqueous media
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Palladium/bipyridine catalyzed conjugate addition of arylboronic acids to α,β-unsaturated carbonyl compounds in aqueous media was developed with high yields.
- Lin, Shaohui,Lu, Xiyan
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p. 7167 - 7170
(2007/10/03)
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- Aryl trihydroxyborates: Easily isolated discrete species convenient for direct application in coupling reactions
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A conceptually and practically simple alternative approach to the use of arylboron species as the organometallic component in cross-coupling processes is described whereby trihydroxyborate salts are isolated and directly employed. The protocol derives practical benefit from the ease and convenience of the isolation and subsequent use of the discrete borate salts, eliminates the need for additional base, and aids the use of correct reaction stoichiometry.
- Cammidge, Andrew N.,Goddard, Victoria H. M.,Gopee, Hemant,Harrison, Nicola L.,Hughes, David L.,Schubert, Christopher J.,Sutton, Benjamin M.,Watts, Gary L.,Whitehead, Andrew J.
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p. 4071 - 4074
(2007/10/03)
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- Pd(II)-bipyridine catalyzed conjugate addition of arylboronic acid to α,β-unsaturated carbonyl compounds
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A Pd(II)-catalyzed conjugate addition of arylboronic acid to α,β-unsaturated ketones, aldehydes, esters, etc. in the presence of 2,2′-bipyridine was developed. A mechanism involving transmetalation, insertion of the carbon-carbon double bond into the C-Pd bond, and protonolysis of the resulting C-Pd bond is proposed. The reaction conditions are mild and the yield is high. The presence of 2,2′-bipyridine is crucial for the reaction to inhibit β-hydride elimination.
- Lu, Xiyan,Lin, Shaohui
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p. 9651 - 9653
(2007/10/03)
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- Rhodium-catalysed 1,4-addition of diarylindium hydroxides to α,β-unsaturated carbonyl compounds
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Diarylindium(III) hydroxides react with α,β-unsaturated carbonyl compounds in the presence of a rhodium catalyst to afford the 1,4-addition products in high yield. This reaction demonstrates the utility of diarylindium(III) hydroxide as an aryl source with rhodium catalysts. The Royal Society of Chemistry 2005.
- Miura, Tomoya,Murakami, Masahiro
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p. 5676 - 5677
(2007/10/03)
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- Rhodium-catalyzed 1,4-addition of arylboronic acids to α,β-unsaturated carbonyl compounds: Large accelerating effects of bases and ligands
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The effects of ligands and bases in the rhodium(I)-catalyzed 1,4-addition of arylboronic acids to α,β-unsaturated carbonyl compounds were reinvestigated to carry out the reaction under mild conditions. Rhodium(I) complexes possessing a 1,5-cyclooctadiene (cod) and a hydroxo ligand such as [RhOH(cod)]2 exhibited excellent catalyst activities compared to those of the corresponding rhodium-acac or -chloro complexes and their phosphine derivatives. The reaction was further accelerated in the presence of KOH, thus allowing the 1,4-addition even at 0 °C. A cationic rhodium-(I)-(R)-binap complex, [Rh(R-binap)(nbd)]BF4, catalyzed the reaction at 25-50 °C in the presence of Et3N with high enantioselectivities of up to 99% ee for α,β-unsaturated ketones, 92% for aldehydes, 94% for esters, and 92% for amides.
- Itooka, Ryoh,Iguchi, Yuki,Miyaura, Norio
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p. 6000 - 6004
(2007/10/03)
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- Conjugate addition of aryl boronic acids to enones catalyzed by cationic palladium(II)-phosphane complexes
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A cationic palladium complex was found to be an efficient catalyst for the 1,4-addition of aryl boronic acids to enones at room temperature (see scheme; X= ClO4, OTf, BF4, PF6, or SbF6); Tf=trifluoromethanesulfonyl).
- Nishikata, Takashi,Yamamoto, Yasunori,Miyaura, Norio
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p. 2768 - 2770
(2007/10/03)
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- PROCESS FOR THE PREPARATION OF ENANTIOMERICALLY ENRICHED COMPOUNDS
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Process for the preparation of enantiomerically enriched compounds with Formula Ar-C(R1)-C(R2)-Z wherein Ar represents an optionally substituted (hetero)aryl group, R1 and R2, each independently, represent H, an alkyl, (hetero)aryl, dialkylamino, amido, thioether, alkoxy or aryloxy group with the proviso that not both R1 and R2 represent H, or R1 and R2 form together with the C-atoms to which they are bound a (hetero)alkyl or (hetero) alkenyl ring and Z represents an electron withdrawing group, in which process a boronic acid derivate of Formula Ar-B(OR3)OR4 or its anhydride, wherein Ar is as described above and R3 and R4, each independently, represent H or an alkyl group, is reacted with an olefinic unsaturated compound with Formula R2 - C = C - (R1)Z, wherein R1, R2 and Z are as described above, in the presence of a transition metal catalyst comprising a transition metal chosen from Cu and group VIII of the Periodic Table and an enantiomerically enriched ligand L, having the Formula (I) where Cn together with the two O-atoms and the P-atom forms a substituted or non-substituted ring with 2-6 C-atoms, R5 and R6 each independently stand for H, an optionally substituted alkyl, aryl, alkaryl, or aralkyl group, or represent the group with Formula (II) wherein Cn1 may have the same meanings as given for Cn and B represents a bridging group, or R5 and R6 may form a heterocyclic ring together with the N-atom to which they are bound.
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- A conjugate addition of arylboronic acids to α,β-unsaturated carbonyl compounds catalyzed by 2β-CD-[Rh(OH)(cod)]2 or [RhCl(cod)]2 in a single aqueous medium
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The rhodium-catalyzed conjugate addition of tolylboronic acid to α,β-unsaturated ketones, esters or amides was carried out in water. [RhCl(cod)]2 and 2β-cyclodextrin-[Rh(OH)(cod)]2 complexes were found to catalyze the reaction efficiently in a single aqueous medium.
- Itooka, Ryoh,Iguchi, Yuki,Miyaura, Norio
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p. 722 - 723
(2007/10/03)
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- Conjugate addition of arylsilanes to unsaturated carbonyl compounds catalyzed by rhodium in air and water
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ArSiCl3 and Ar2SiCl2, believed to be unstable in aqueous media, reacted efficiently with α,β-unsaturated ketones and esters in air and water (in the presence of sodium fluoride and a rhodium catalyst), giving good to excellent yields of the desired conjugate addition products.
- Huang,Li
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p. 2348 - 2349
(2007/10/03)
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- Quasi-nature catalysis: Conjugated addition of unsaturated carbonyl compounds with aryl and vinyltin reagents catalyzed by rhodium in air and water
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In air and water, trialkylphenyl- or trialkylvinylstannanes react with α,β-unsaturated esters and ketones to give the corresponding conjugated addition products in high yields in the presence of a rhodium catalyst.
- Venkatraman, Sripathy,Meng, Yue,Li, Chao-Jun
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p. 4459 - 4462
(2007/10/03)
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- A New Catalytic Activity of Antimony(III) Chloride in Palladium(0)-Catalyzed Conjugate Addition of Aromatics to α,β-Unsaturated Ketones and Aldehydes with Sodium Tetraphenylborate and Arylboronic Acids
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A remarkable catalytic effect of antimony(III) chloride is disclosed in palladium(0)-catalyzed conjugate addition of aromatics to α,β-unsaturated ketones and aldehydes with sodium tetraphenylborate and arylboronic acids in acetic acid at 25 deg C.Several other metal chlorides such as AlCl3, SnCl4, AsCl3, TiCl4, FeCl3, MoCl5, and CeCl3 are also effective in some cases, but SbCl3 is the salt of choice.Two key steps are proposed for this reaction: one is the oxidative addition of a C-B bond to Pd(0) forming an arylpalladium species, and the other is the formation of an antimony enolate derived from the initial coordination of SbCl3 to the carbonyl oxygen of an organopalladium intermediate.
- Cho, Chan Sik,Motofusa, Shin-ichi,Ohe, Kouichi,Uemura, Sakae,Shim, Sang Chul
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p. 883 - 888
(2007/10/02)
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- Organocalcium Chemistry: Preparation and Reactions of Highly Reactive Calcium
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A highly reactive form of calcium was prepared by the reduction of Ca(II) salts with preformed lithium biphenylide.Remarkably, this activated calcium undergoes oxidative addition to organic bromides, chlorides, or even fluorides to form the organocalcium reagents under very mild conditions in high yields.The resulting organocalcium compounds undergo Grignard-type reactions.Transmetalation with Cu(I) salts forms calcium cuprate reagents which undergo a variety of cross-coupling reactions.The activated calcium reacts with 1,3-dienes to yield the corresponding 2-butene-1,4-diylcalcium complexes.These bis-organocalcium reagents can undergo dialkylation reactions with α,ω-alkylene dihalides and dichlorosilanes to form the corresponding 3-, 5-, and 6-membered ring derivatives.Significantly, these reactions are highly stereospecific and regioselective.
- Wu, Tse-Chong,Xiong, Heping,Rieke, R. D.
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p. 5045 - 5051
(2007/10/02)
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- Reversal of ?-Facial Diastereoselection upon Electronegative Substitution of the Substrate and the Reagent
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Electonegative substitution at C-3 of cyclohexanone and methylenecyclohexane is found to increase the relative proportion of axial attack in a number of reactions widely differing from the points of view of the transition-state polarization, geometry, and
- Cieplak, Andrzej S.,Tait, Bradley D.,Johnson, Carl R.
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p. 8447 - 8462
(2007/10/02)
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- REACTIONS OF ARYLAZO ARYL SULFONES WITH α,β-UNSATURATED ESTERS AND KETONES CATALYZED BY PALLADIUM(0) COMPLEX
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The palladium(0) catalyzed reactions of arylazo aryl sulfones (1) with α,β-unsaturated esters in benzene give aryl-substituted esters as major products and hydroarylated esters as minor products.The reactions of 1 with acyclic α,β-unsaturated ketones give considerable amounts of hydroarylated ketones and aryl-substituted ketones under similar conditions, whereas the reactions of 1 with cyclic α,β-unsaturated ketones afforded selectively hydroarylated compounds and no formation of aryl-substituted ketones was found.A plausible reaction mechanism is proposed.Key words: Arylazo aryl sulfones; palladium(0) catalyst; arylation; α,β-unsaturated carbonyl compounds; diarylpalladiumII) intermediate; catalytic cycle.
- Kamigata, Nobumasa,Satoh, Akira,Yoshida, Masato
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p. 121 - 130
(2007/10/02)
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- Ultrasound in Organic Synthesis. 7. Preparation of Organozinc Reagents and Their Nickel-Catalyzed Reactions with α,β-Unsaturated Carbonyl Compounds
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Diorganozinc compounds can be prepared with great ease and efficiency in a one-pot process, by sonication of lithium, an organic halide, and a zinc halide in THF or toluene mixtures.The reagents thus obtained give rise to clean and selective conjugate additions to α,β-unsaturated aldehydes and ketones in the presence of catalytic amounts of nickel acetylacetonate.
- Petrier, Christian,Barbosa, Jayne C. de Souza,Dupuy, Claude,Luche, Jean-Louis
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p. 5761 - 5765
(2007/10/02)
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