- Asymmetric allylic alkylation catalyzed by palladium complexes with new chiral ligands
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A potential chiral tridentate ligand based on 2,6-disubstituted pyridine has been prepared and its palladium complexes have been used in asymmetric allylic alkylation. Up to 75% ee is achieved in the reaction between 1,3-diphenyl-2-propenyl acetate and di
- Zhu, Guoxin,Terry, Michael,Zhang, Xumu
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Read Online
- On the Origin of Asymmetric Induction of the Palladium-Catalyzed Allylic Substitution Reaction with Chiral 4,4-Disubstituted 4,5-Dihydro-2-(phosphinoaryl)oxazole Ligands
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The X-ray analyses of (η 3-allyl){4-benzyl-2-[2-(diphenylphosphino-κP)phenyl]-4,5- dihydro-4-methyloxazole-κN}palladium(II) hexafluorophosphate (5) and the analogous [Pd(η3-1,3-diphenylallyl)] complex 6 are presented. A comparison wi
- Schaffner, Silvia,Mu?ller, Ju?rgen F. K.,Neuburger, Markus,Zehnder, Margarets
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- Catalytic materials based on catalysts containing ionic liquid phase supported on chitosan or alginate: Importance of the support
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Catalysts containing an ionic liquid phase immobilised on chitosan or alginate supports are successfully applied to the palladium catalysed allylation and amination reactions. The influence of the chemical structure of the support not only on the activity
- Clousier, Nathalie,Moucel, Renaud,Naik, Prashant,Madec, Pierre-Jean,Gaumont, Annie-Claude,Dez, Isabelle
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- Synthesis of xanthene-derived diimine and iminophosphine compounds as potential chiral bidentate ligands
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The synthesis of one diimine and two iminophosphine chiral ligands bearing a xanthene backbone in, respectively, four and five steps is described. The diimine is characterised by X-ray crystallography. A preliminary test in palladium-catalysed asymmetric allylic alkylation is reported.
- Malaisé, Grégory,Barloy, Laurent,Osborn, John A
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- Macrocyclic vs acyclic derivatives of chiral bis(oxazolines); ligand distortion and enantioselectivity of Pd(II) complexes in catalytic allylic alkylation
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Pd(II) complexes of acyclic (1,2;4,5) and macrocyclic (3,6-10) derivatives of 1,5-bis(oxazolines), are tested in the enantioselective allylic alkylation of racemic 1,3-diphenyl-3-acetoxyprop-2-ene (14) by dimethylmalonate anion to allyl malonate derivativ
- ?epac, Dragan,Marini?, ?eljko,Portada, Tomislav,?ini?, Mladen,?unji?, Vitomir
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- Synthesis of ferrocenylglucose phosphonite and bisphosphinite: Pd(II) and Pt(II) complexes, Pd-catalyzed allylic alkylation
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The synthesis and characterization of the new phosphorus containing ligands and the corresponding Pd(II) and Pt(II) complexes are reported. The molecular structure of 4,6-bis-O-(diphenylphosphino)-2,3-(ferrocene-1,1′-dicarbonyl)-O- methyl-α-D-glucopyranos
- Nazarov, Alexey A,Hartinger, Christian G,Arion, Vladimir B,Giester, Gerald,Keppler, Bernhard K
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- Rapid assembly and synthetic applications of a supported poly-α-amino acid containing phosphine groups
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A simple method for the rapid multiplication of the number of available amine sites on a polymer bead, using lysine N-carboxyanhydride, is described. The product may be functionalised with a phosphine and employed in a catalytic reaction. (C) 2000 Elsevier Science Ltd.
- Edwards,Shipton,Wills
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- Further developments in metal-catalysed C-C bond cleavage in allylic dimethyl malonate derivatives
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The use of a catalytic amount of nickelbis(1,4-bis(diphenylphosphino)butane in DMF enables the activation of the C-C bond in dimethyl allylmalonate derivatives to proceed under rather smooth reaction conditions, without added nucleophile. Several exmnples like isomerization of substituted-allyl malonate derivatives, racemization of chiral products, but also a synthetic application as an inverse disproportionation reaction are described.
- Bricout, Herve,Carpentier, Jean-Francois,Mortreux, Andre
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- Allyl-palladium complexes with fluorinated benzene thiolate ligands. Examination of the electronic effects in the Pd-catalyzed allylic alkylation reaction with the catalytic system [(η3-C3H5)Pd(μ-SRf)]2
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The bimetallic complexes [(η3-C3H5)Pd(μ-SRf)]2 [Rf = C6F5, (1); C6F4H-4, (2); C6H4F-2, (3); C6H4F-3,
- Redón, Rocío,Torrens, Hugo,Wang, Zhaohui,Morales-Morales, David
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- Air-stable P-stereogenic secondary phosphine oxides as chiral monodentate ligands for asymmetric catalytic carbon-carbon bond formation
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P-Stereogenic secondary phosphine oxides are configurationally stable in the presence of metal ions both in solution and in the solid state. They have the potential to serve as chiral monodentate phosphorus ligands for asymmetric catalysis. In the asymmet
- Dai, Wei-Min,Yeung, Kelly Ka Yim,Leung, Wa Hung,Haynes, Richard K.
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Read Online
- Insight in chitosan aerogels derivatives -Application in catalysis
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Thanks to an aerogel formulation, an efficient heterogeneous modification of chitosan is described and offers the convenient covalent-functionalisation of primary amine of insoluble microspheres into secondary benzylic-amines with various functionalities.
- Le Goff, Ronan,Mahé, Olivier,Le Coz-Botrel, Ronan,Malo, Sylvie,Goupil, Jean-Michel,Brière, Jean-Fran?ois,Dez, Isabelle
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Read Online
- Steric and chelate ring size effects on the enantioselectivity in palladium-catalyzed allylic alkylation with new chiral P,N-ligands
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New chiral P,N-ligands derived from substituted pyridine and (S)-2,2′-binaphthol phosphorochloridite have been prepared and tested in asymmetric palladium-catalyzed allylic alkylations. The enantioselectivity was poorly dependent on the pyridine substitue
- Arena, Carmela Grazia,Drommi, Dario,Faraone, Felice
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Read Online
- Ligand-Free, Quinoline N-Assisted Copper-Catalyzed Nitrene Transfer Reaction to Synthesize 8-Quinolylsulfimides
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An efficient copper-catalyzed, quinolyl N-directed nitrene transfer reaction to 8-quinolylsulfides was described. A variety of 8-quinolylsulfimides with different functional groups were synthesized in moderate to high yields. The obtained 8-quinolylsulfimides were proved to be promising novel type of bidentate ligands in Pd(II)-catalyzed allylic alkylation.
- Xiao, Xinsheng,Huang, Sanping,Tang, Shanshan,Jia, Guokai,Ou, Guangchuan,Li, Yangyan
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p. 7618 - 7629
(2019/06/27)
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- S - alkyl - S - quinolyl - N - sulfonyl-nitrogen-sulfur ylide compound and its preparation and use (by machine translation)
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The invention belongs to the field of organic synthesis, specifically provides the S - alkyl - S - quinolyl - N - sulfonyl-nitrogen-sulfur ylide compound. In addition, the invention also provides the preparation method of the compound, its by 8 - mercapto
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Paragraph 0153; 0154; 155; 0156; 0157; 0158
(2019/06/11)
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- Ligand's electronegativity controls the sense of enantioselectivity in BIFOP-X palladium-catalyzed allylic alkylations
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Palladium-catalyzed allylic alkylations of sodium dimethyl malonate with 1,3-diphenylallyl acetate, employing BIFOP-H (biphenylbisfencholphosphite) and analogue (i.e. BIFOP-X, X = D, Cl, CN, N3) ligands, all yield (S)-enantiomeric products, while alkylations to cyclohexenyl acetate yield the (R)-enantiomeric C-C coupling product (up to 91% yield, 70% ee). The fluoro derivative BIFOP-F however, "switches" the sense of enantioselectivity, yielding the (R)-enantiomer for 1,3-diphenylallyl acetate and the (S)-enantiomer for the cyclohexenyl acetate (up to 92% yield, 67% ee). Computational analyses of transition structures (M06-2X-D3/def2-TZVP//B3LYP-D3(BJ)/def2-SVP) for these Pd-catalyzed allylic alkylations reproduce the experimental preference of BIFOP-H (and analogue BIFOP-X ligands) for (R)- or (S)-enantiomeric products of 1,3-diphenylallyl or cyclohexenyl acetate, respectively. The "F-switch" of the sense of enantioselectivity from BIFOP-H to BIFOP-F is also apparent computationally and is found (NBO-analyses) to originate from lp(Pd) → σ?(P-O) or lp(Pd) → σ?(P-F) hyperconjugations. The higher electronegativity of F vs. H in BIFOP-X hence controls the sense of enantioselectivity of this Pd-catalyzed allylic alkylation.
- Brüllingen, Eric,Neud?rfl, J?rg-Martin,Goldfuss, Bernd
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p. 15743 - 15753
(2019/10/19)
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- Amino thiazoline chiral ligand and preparation method and application thereof
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The invention discloses an amino thiazoline chiral ligand compound with a benzene ring as a framework and a preparation method and application of the compound. O-nitrobenzoic acid serves as the raw material, chiral amino alcohol serves as a chiral source,
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Paragraph 0049-0050
(2017/08/28)
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- Modular bisphosphine ligands: Preparation and application in enantioselective catalytic reactions
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A set of six chiral modular C2-symmetric bisphosphine ligands have been synthesized in a straightforward manner through a two-step reaction from the corresponding diols with moderate yields. The applicability of these chiral ligands was evaluated in ruthenium(II)-catalyzed transfer hydrogenation reactions (up to >99% conversion) and palladium(0)-catalyzed enantioselective allylic substitution reactions (up to 70% chemical yield and 43% ee).
- G?k, Ya?ar,Karayi?it, ?lker ümit,G?k, Halil Zeki
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- Ferrocene framework N, N ligand as well as preparation method and application thereof
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The invention relates to a novel chiral N, N ligand which is shown in the structural general formula, wherein R1 is C1-C7 alkyl, aryl or substituted aryl, R2 is hydrogen or C1-C7 alkyl-substituted silicyl, R3 is hydroxyl or C1-C7 alkoxyl, R4 is hydrogen,
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Paragraph 0036
(2016/10/27)
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- A new type of ferrocene-based phosphine-tert-butylsulfinamide ligand: Synthesis and application in asymmetric catalysis
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A new type of ferrocene-based phosphine-tert-butylsulfinamide ligand has been synthesized and applied to the enantioselective formation of C-C and C-N bonds. The palladium complex derived from ligand 4a was an efficient catalyst in asymmetric allylic substitution of several substrate types. Enantioselectivites with the difficult substrate 3-acetoxycyclohexene of up to 91% ee are achieved.
- Ma, Jiangwei,Li, Chuang,Zhang, Dongxu,Lei, Yang,Li, Muqiong,Jiang, Ru,Chen, Weiping
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p. 35888 - 35892
(2015/05/05)
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- Palladium-catalyzed allylic alkylation using chiral P,O-ligands synthesized via sulfonamide directed ortho-lithiation
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An efficient approach for the synthesis of chiral P,O-ligands containing sulfonamide and phosphine moieties is designed. The introduction of the chirality is achieved through different stereogenic groups attached to the sulfonamide nitrogen. The highly ef
- Petkova, Zhanina,Stoyanova, Malinka,Dimitrov, Vladimir
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p. 2093 - 2096
(2014/04/03)
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- Highly enantioselective alkylation of allyl acetates using tartrate-derived bioxazoline ligands
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Tartrate-derived bioxazoline ligands, which form a five-membered chelate ring with metals, were evaluated for use in the asymmetric allylic alkylation (AAA) reactions of various symmetrical and unsymmetrical allyl acetates. Excellent enantioselectivities
- Jayakumar, Samydurai,Prakash, Muthuraj,Balaraman, Kaluvu,Kesavan, Venkitasamy
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p. 606 - 615
(2014/02/14)
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- Synthesis and Reactivity of Chiral, Wide-Bite-Angle, Hybrid Diphosphorus Ligands
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Effective and modular synthetic approaches toward phosphine-phosphite ligands and phosphine-phosphonite ligands featuring a diphenyl ether backbone have been developed. The phosphine-phosphite ligands are obtained by a two-step protocol from 2-bromo-2′-methoxydiphenyl ether. The phosphine-phosphonite ligands are prepared in a four-step synthetic protocol that involves a novel, unsymmetrical diphenyl ether derived phosphine-phosphorusdiamide as key building block. Structural studies on PtII complexes with either phosphine-phosphite or phosphine-phosphonite ligands indicate strict cis coordination for these ligand systems. High-pressure NMR spectroscopy studies of Rh complexes under syngas indicate the presence of two ea isomers for Rh(H)(CO)2(PP). The existence of this mixture is further supported by high-pressure IR spectroscopy studies. In order to benchmark the activity and selectivity of these novel, wide-bite-angle, mixed-donor ligands, they were screened in Pd-catalyzed asymmetric allylic alkylation as well as Rh-catalyzed hydrogenation and hydroformylation reactions. The ligands give 100-% conversion and low-to-moderate enantioselectivity in the allylic alkylation of 1,3-diphenyl-2-propenyl acetate and cyclohexyl-2-enyl acetate with dimethyl malonate. In the hydroformylation of styrene, good conversion and regioselectivities are achieved but only moderate enantioselectivity. The ligands give good conversions in asymmetric hydrogenation of typical substrates, with good-to-excellent enantioselectivities of up to 97-% depending on the substrate. Copyright
- Czauderna, Christine Fee,Cordes, David B.,Slawin, Alexandra M. Z.,Müller, Christian,Van Der Vlugt, Jarl Ivar,Vogt, Dieter,Kamer, Paul C. J.
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p. 1797 - 1810
(2014/04/17)
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- P-CHIROGENIC ORGANOPHOSPHORUS COMPOUNDS
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The present invention relates to novel P-chirogenic organophosphorus compounds of general formula (I). The present invention also provides a process for the synthesis of said compounds of formula (I). The present invention also relates to intermediate products of general formulae (II), (III) and (IV), as shown below, which are involved in the synthesis of compounds (I). Further, the invention relates to metal complexes comprising compounds (I) as ligands. The novel compounds and complexes of the present invention are useful in asymmetric catalysis by transition metal complexes or organocatalysis, especially for asymmetric hydrogenation or allylation. Compounds of general formula (I) may useful as agrochemical and therapeutic substances, or as reagents or intermediates for fine chemistry.
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Page/Page column 92; 93
(2013/03/26)
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- Development of Plowast-monodentate diamidophosphites with a C1-symmetric 1,2-diamine backbone: The effects of substituents in the 1,3,2-diazaphospholidine cycle on Pd-catalyzed asymmetric allylations
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We have designed and synthesized a small library of modular monodentate diamidophosphite ligands with stereogenic phosphorus atoms. The library was prepared efficiently from the commercially available and inexpensive (S)-N-Boc-amino acids. These novel ligands were screened in the Pd-catalyzed asymmetric allylations of (E)-1,3-diphenylallyl acetate with dimethyl malonate as the C-nucleophile with up to 93% ee being obtained. The results showed that the different substituents in the 1,3,2-diazaphospholidine cycle had remarkable effects on the enantioselectivity.
- Gavrilov, Konstantin N.,Shiryaev, Alexei A.,Zheglov, Sergey V.,Potapova, Oksana V.,Chuchelkin, Ilya V.,Novikov, Ivan M.,Rastorguev, Eugenie A.,Davankov, Vadim A.
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p. 409 - 417
(2013/06/27)
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- A chiral bis(arsine) ligand: Synthesis and applications in palladium-catalyzed asymmetric allylic alkylations
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The new chiral bis(arsine) ligand N,N′-bis[2′-(diphenylarsino) benzoyl]-(1R,2R)-cyclohexanediamine (BiAsBA, 3), based on the backbone of the Trost modular ligand (TML), was synthesized in three steps. A useful approach to introduce the -AsPh2 g
- Uberman, Paula M.,Caira, Mino R.,Martin, Sandra E.
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supporting information
p. 3220 - 3226
(2013/07/19)
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- Palladium-catalyzed insertion of α,β-unsaturated N-tosylhydrazones and trapping with carbon nucleophiles
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Palladium-catalyzed carbene migratory insertion-cyclization reactions were reported, delivering dihydronaphthalene and indene derivatives in moderate to good yields. A three-component cross-coupling was also developed. The reactions are easy to handle, under mild conditions and various functional groups are tolerated. The Royal Society of Chemistry 2013.
- Ye, Yu-Ying,Zhou, Ping-Xin,Luo, Jian-Yi,Zhong, Mei-Jin,Liang, Yong-Min
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supporting information
p. 10190 - 10192
(2013/10/22)
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- Camphane-based phosphino-carboxamide ligands as P,O-chelates in Pd-catalyzed enantioselective allylic alkylation
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A practical synthesis for new chiral phosphino-carboxamide ligands has been accomplished. These ligands were effectively modified both on the amide moiety and the phosphine atom. Application of these ligands in the Pd-catalyzed allylic alkylation of (E)-1
- Philipova, Irena,Stavrakov, Georgi,Dimitrov, Vladimir
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scheme or table
p. 927 - 930
(2012/10/07)
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- Phosphites and diamidophosphites based on mono-ethers of BINOL: A comparison of enantioselectivity in asymmetric catalytic reactions
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Novel P-monodentate phosphite-type ligands have been synthesized in one step from BINOL mono-tosylate and BINOL mono-(-)-menthylcarbonate. The use of these ligands provides up to 96% ee in Pd-catalyzed asymmetric allylic substitution of (E)-1,3-diphenylal
- Gavrilov, Konstantin N.,Zheglov, Sergey V.,Gavrilova, Mariya N.,Novikov, Ivan M.,Maksimova, Marina G.,Groshkin, Nikolay N.,Rastorguev, Eugenie A.,Davankov, Vadim A.
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supporting information; experimental part
p. 1581 - 1589
(2012/03/08)
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- 'ClickCarb': Modular sugar based ligands via click chemistry
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Reported is a modular approach for the synthesis of a number of structurally diverse ligands derived from carbohydrates. The use of the highly functional hydroxy amino azide 1 derived from glucosamine allows the synthesis of a number of useful ligands for organic and organometallic catalyses. The key step of the approach is the Huisgen cycloaddition of the anomeric sugar azide and diverse alkynes.
- Khiar, Noureddine,Navas, Raquel,Fernández, Inmaculada
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supporting information; experimental part
p. 395 - 398
(2012/02/02)
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- Palladium-catalyzed asymmetric allylic substitutions in the presence of chiral phosphine-imine type ligands
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Chiral bidentate phosphine-imine type ligand L9 is fairly effective in the asymmetric allylic substitution of 1,3-diphenylpropenyl acetate with dimethyl malonate to give the corresponding adduct in moderate yield and good ee.
- Sun, Yin-Wei,Jiang, Jia-Jun,Zhao, Mei-Xin,Wang, Fei-Jun,Shi, Min
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supporting information; experimental part
p. 2850 - 2856
(2011/08/10)
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- Synthesis of phosphorylated sulfoximines and sulfinamides and their application as ligands in asymmetric metal catalysis
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Starting from inexpensive materials and following simple protocols various N-phosphorylated sulfoximines and sulfinamides have been synthesized. The newly prepared compounds were then applied as chiral ligands in asymmetric transition metal catalysis. Pho
- Benetskiy, Eduard B.,Bolm, Carsten
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scheme or table
p. 373 - 378
(2011/05/06)
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- Efficient iron-catalyzed Tsuji-trost coupling reaction of aromatic allylic amides through a sp3-carbon-nitrogen breaking
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The catalytic activation of sp3-carbon-nitrogen of allylic amides is generally difficult because of the inefficient leaving-group ability of the amide group. In this article, we have discovered for the first time that FeCl3-catalyzed Tsuji-Trost coupling reaction of aromatic allylic amides with active methylene compounds, cyclohexanone, and allytrimethylsilane work efficiently under mild conditions. Georg Thieme Verlag Stuttgart.
- Jiang, Zhen-Yu,Zhang, Cai-Hua,Gu, Feng-Lei,Yang, Ke-Fang,Lai, Guo-Qiao,Xu, Li-Wen,Xia, Chun-Gu
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supporting information; experimental part
p. 1251 - 1254
(2010/08/05)
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- Synthesis of new fluorous modular chiral ligand derivatives from amino alcohols and application in enantioselective carbon-carbon bond-forming alkylation reactions
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N-Trifluoracyl β-chalcogeno amides and N-perfluoracyl β-thio amide ligands were prepared by a simple and efficient reaction sequence. These new ligands were evaluated in palladium-catalyzed alkylation of rac-(E)-1,3-diphenyl-2-propenyl acetate in the pres
- Sehnem, Jasquer A.,Milani, Priscila,Nascimento, Vanessa,Andrade, Leandro H.,Dorneles, Luciano,Braga, Antonio L.
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experimental part
p. 997 - 1003
(2010/08/22)
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- Sulfoxides derived from Cinchona alkaloids - Chiral ligands in palladium-catalyzed asymmetric allylic alkylation
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Phenyl sulfides derived from Cinchona alkaloids, 9-PhS-epi-CD, 9-PhS-epi-QN, 9-PhS-epi-QD, and 9-PhSQN were oxidized into the corresponding sulfoxides. Regardless of the oxidation system used (NaIO4, TEMPO/NaOCl, VO(acac)2/chiral Schiff base/H2O2) a similar stereochemical outcome of the oxidation was observed. Four pure epimers of sulfoxides 9-PhSO-epi-CD and 9-PhSO-epi-QN were isolated and fully characterized (X-ray, CD, 1H NMR-pattern). The chiral sulfoxides as well as the corresponding sulfides and sulfones were tested in the Pd-catalyzed allylic alkylation of dimethyl malonate with rac-1,3-diphenyl-2-propenyl acetate. The sulfoxides obtained from Cinchona alkaloids bearing the additional stereogenic center gave the main product of configuration dependent on the chirality of alkaloid framework only. Similar ees (up to 60%) but significantly higher yields (90%) were obtained as compared to the reaction with the corresponding thioethers. The results were in agreement with nucleophilic attack directed at the allylic carbon located trans to the sulfur atom in the M-shaped intermediate η3-allylpalladium complex.
- Wojaczynska, Elzbieta,Zielinska-Blajet, Mariola,Turowska-Tyrk, Ilona,Skarzewski, Jacek
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experimental part
p. 853 - 858
(2010/11/02)
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- Carbohydrate-based spiro bis(isoxazolines): synthesis and evaluation in asymmetric catalysis
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Two carbohydrate-based spiro bis(isoxazolines) were synthesized via 1,3-dipolar cycloaddition from peracetylated methylene exo-glucal and the corresponding bis(arylnitrile oxide). The bis(cycloadducts) were then evaluated as ligands for enantioselective catalytic reactions. The Pd-catalyzed Tsuji-Trost reaction between a malonate and an allylic acetate did not provide good results. The poor conversion observed can be attributed to the rearrangement of the ligand in the reaction mixture to afford the corresponding ring-opened isoxazole which has been characterized. Both ligands were also evaluated in Cu(I)-catalyzed asymmetric imine alkynylation and afforded the product in good yield and modest enantioselectivity.
- Goyard, David,Telligmann, Susanne M.,Goux-Henry, Catherine,Boysen, Mike M.K.,Framery, Eric,Gueyrard, David,Vidal, Sébastien
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supporting information; experimental part
p. 374 - 377
(2010/03/24)
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- Asymmetric C-C bond-formation reaction with Pd: How to favor heterogeneous or homogeneous catalysis?
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The enantioselective allylic alkylation of (E)-1,3-diphenylallyl acetate was studied to clarify the heterogeneous or homogeneous character of the Pd/Al2O3-(R)-BINAP catalyst system. A combined approach was applied: the catalytic test
- Reimann, Sven,Grunwaldt, Jan-Dierk,Mallat, Tamas,Baiker, Alfons
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experimental part
p. 9658 - 9668
(2010/10/20)
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- Asymmetric allylic alkylation by palladium-bisphosphinites
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A series of new chiral palladium-bisphosphinite complexes have been prepared from readily available, naturally occurring chiral alcohols. The complexes were used to efficiently carry out catalytic allylic alkylation of 1,3-diphenylpropene-2-yl acetate wit
- Sharma, Rakesh K.,Nethaji, Munirathnam,Samuelson, Ashoka G.
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p. 655 - 663
(2008/09/20)
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- Modular synthesis of chiral N-protected β-seleno amines and amides via cleavage of 2-oxazolidinones and application in palladium-catalyzed asymmetric allylic alkylation
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A set of chiral β-seleno amines have been efficiently synthesized via the ring-opening reaction of chiral N-acyl oxazolidinones by selenium nucleophiles. These compounds could be transformed into β-seleno amides by reaction with acid chlorides. The presen
- Sehnem, Jasquer A.,Vargas, Fabricio,Milani, Priscila,Nascimento, Vanessa,Braga, Antonio L.
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p. 1262 - 1268
(2008/12/22)
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- Selective nucleophilic substitution using pyrazolate anions: Easy approach to modular chiral ligands with complexing pyrazole moieties
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A simple method for the stereoselective synthesis of 3,5-disubstituted pyrazolyl alcohols from readily available chiral epoxides is reported. The key step of the synthesis is the ring-opening reaction, which occurs by a regio- and enantioselective nucleophilic substitution with pyrazolate anions. An analogous reaction of the pyrazolate anions gave nonracemic (pyrazolyl)oxazolines. Thus obtained modular pyrazole chiral ligands were tested in the Pd-catalyzed Tsuji-Trost and Cu-catalyzed asymmetric cyclopropanation reactions and the enantioselectivities up to 52% ee and 64% ee were attained in both model reactions, correspondingly.
- Kowalczyk,Skarzewski
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p. 1987 - 1999
(2008/09/18)
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- Influence on the enantioselectivity in allylic alkylation of the anomeric position of the phosphine-amide ligands derived from d-glucosamine
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The synthesis of a new series of chiral phosphine amides derived from d-glucosamine is described. The palladium-catalyzed asymmetric allylic alkylations of racemic (E)-1,3-diphenyl-2-propenyl acetate with dimethyl malonate using these ligands have been in
- Glego?a, Katarzyna,Framery, Eric,Goux-Henry, Catherine,Micha? Pietrusiewicz,Sinou, Denis
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p. 7133 - 7141
(2008/02/07)
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- Novel benzoferrocenyl chiral ligands: Synthesis and evaluation of their suitability for asymmetric catalysis
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Four benzoferrocenyl phosphorus chiral ligands were conveniently prepared in good overall yields. These ligands were found to be stable in solid form and in solution. Two of the four ligands were resolved by chiral HPLC. Unlike a reported bis(phosphino-η
- Thimmaiah, Muralidhara,Luck, Rudy L.,Fang, Shiyue
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p. 1956 - 1962
(2007/10/03)
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- First allylpalladium systems containing chiral imidazolylpyridine ligands - Structural studies and catalytic behaviour
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Palladium/chiral imidazolylpyridine systems were tested in allylic alkylation of rac-3-acetoxy-1,3-diphenyl-1-propene (rac-I) and 3-acetoxy-1-phenyl-1-propene (II), paying particular attention to the influence of the amine nitrogen hybridisation on their catalytic behaviour. Allylpalladium complexes 9-11 containing optically pure imidazolines were synthesised and fully characterised both in solution (NMR) and the solid state (single-crystal X-ray diffraction). NMR studies showed four species in solution for complex 9 containing the unsymmetrical 1-phenylallyl group, while for 10 and 11, involving the symmetrical 1,3-diphenylallyl moiety, two species, endo and exo, were identified. In the solid state, only endo isomers crystallised for each complex. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Bastero, Amaia,Bella, Antonio F.,Fernandez, Fernando,Jansat, Susanna,Claver, Carmen,Gomez, Montserrat,Muller, Guillermo,Ruiz, Aurora,Font-Bardia, Merce,Solans, Xavier
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p. 132 - 139
(2007/10/03)
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- Allylic alkylation and amination using mixed (NHC)(phosphine) palladium complexes under biphasic conditions
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A dramatic improvement of the catalytic activity was observed when a phosphine was added in allylic alkylation reactions catalyzed by (NHC)Pd(η3-C3H5)Cl complexes. Consequently, several palladium complexes, generated in situ from different NHC-silver complexes, [Pd(η3-C3H5)Cl]2 and PPh3, were tested in this reaction to evaluate their potential. High reaction rates and conversions could be obtained with this catalytic system in the alkylation of allylic acetates with dimethylmalonate, particularly under biphasic conditions using water/dichloromethane and KOH 1 M as the base. These conditions are experimentally more convenient and gave higher reaction rates than the classical anhydrous conditions (NaH/THF). In this system, the phosphine is essential since no conversion was obtained when it is not present. The steric hindrance of the carbene ligand has a great influence on the activity and the stability of the catalytic system. The best NHC ligands for this reaction are either 1-mesityl-3-methyl-imidazol-2-ylidene or 1-(2,6-diisopropylphenyl)-3-methyl-imidazol-2-ylidene which are less bulky among the NHC tested. These two ligands led in 5 min to a complete conversion at 20 °C. The Pd-catalyzed allylic amination reaction using (E)-1,3-diphenylprop-3-en-yl acetate and benzylamine was also tested with (NHC)(PPh3)Pd complexes and under the biphasic conditions. This reaction was found to be slower than the alkylation with dimethylmalonate but a complete conversion could be reached in 6 h at 20 °C using K2CO3 1 M as the base. NMR experiments indicated that mixed (NHC)(PPh3)Pd complexes are formed in situ but their structure could not be established exactly.
- Flahaut, Alexandre,Roland, Sylvain,Mangeney, Pierre
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p. 5754 - 5762
(2008/03/13)
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- A diaminocarbene-phosphonium ylide: Direct access to C,C chelating ligands
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(Chemical Equation Presented) Captured and surrounded by C: A strongly σ-donating C,C ligand and an allyl ligand surround the palladium center in the complex shown in the scheme. The chelate, with three different types of carbon atoms, is soluble and stab
- Canac, Yves,Duhayon, Carine,Chauvin, Remi
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p. 6313 - 6315
(2008/09/18)
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- Fine-tuning ligands for catalysis using supramolecular strategies
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Coordinative bonds have been used to prepare supramolecular ligands leading to well-defined catalysts formed by assembly. The construction of these ligands is based on selective metal-ligand interactions between nitrogen donor atoms of phosphorus-nitrogen building blocks and various zinc(II) porphyrins. The major advantage of this supramolecular approach of catalyst preparation is the simplification of ligand variation enabling straightforward modification of steric, electronic and chiral properties of the supramolecular ligand. A large number of new ligands becomes accessible by this modular variation of the building blocks. The ligand assembly based on pyridyl phosphites and zinc(II) porphyrin with electron-withdrawing substituents led to a twelve-fold increase in activity and an increase in enantioselectjvity from 17 to 50% in the rhodium-catalyzed hydrogenation of dimethyl itaconate. The first examples of assemblies based on non-chiral ligands and chiral zinc(II) porphyrin template molecules show, as proof of principle, an enantiomeric excess up to 18 % in the asymmetric palladium-catalyzed allylic alkylation. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Slagt, Vincent F.,Kaiser, Patrick,Berkessel, Albrecht,Kuil, Mark,Kluwer, Alexander M.,Van Leeuwen, Piet W. N. M.,Reek, Joost N. H.
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p. 4653 - 4662
(2008/03/18)
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- Synthesis of all-cis-3-(2-diphenylphosphinoethyl)-1,2,4-tris(diphenylphosphinomethyl)cyclopentane (Ditricyp) from dicyclopentadiene
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A new tetraphosphine, all-cis-3-(2-diphenylphosphinoethyl)-1,2,4-tris(diphenylphosphinomethyl)cyclopentane (Ditricyp), has been synthesised in seven steps from commercially available dicyclopentadiene. The ozonolysis of dicyclopentadiene occurred first on the double bond of the bicycloheptene moiety. A very high chemoselective ozonolysis was observed at -60 °C leading to the diol after reductive treatment. From this diol, cis,cis,cis-3-(2-hydroxyethyl)-1,2,4-tri(hydroxymethyl)cyclopentane was obtained after a second ozonolysis. Mesylation and substitution with Ph2PLi led to the title tetradiphenylphosphine Ditricyp. The efficiency of this new tetraphosphine ligand for palladium-catalysed coupling reactions has been studied. Satisfactory results in terms of substrate/catalyst ratio have been obtained for Suzuki, Negishi and Sonogashira couplings and also for Heck vinylation reaction. After chromatographic separation, one enantiomer of this ligand associated to palladium was able to induce enantioselective allylic alkylation with modest enantiomeric excess.
- Kondolff, Isabelle,Feuerstein, Marie,Doucet, Henri,Santelli, Maurice
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p. 9514 - 9521
(2008/02/11)
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- Use of zinc enolate, free from other metals, in enantioselective palladium-catalyzed allylic alkylation
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Zinc enolate, free from other metal cations directly prepared from malonate and diethylzinc, was proven to be an excellent nucleophile for enantioselective palladium-catalyzed allylic alkylation, particularly for the allylic cation bearing aromatic rings
- Kinoshita, Naosumi,Kawabata, Takeo,Tsubaki, Kazunori,Bando, Masahiko,Fuji, Kaoru
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p. 1756 - 1763
(2007/10/03)
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- Palladium-catalyzed asymmetric allylic alkylation using chiral pyridyl-hydrazone ligands
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Palladium-catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate (5) with a dimethyl malonate-BSA-LiOAc system has been successfully carried out in the presence of chiral pyridyl-hydrazone ligands such as 2c with moderate enantioselectivities (up to 67% ee).
- Mino, Takashi,Shirae, Yoshiaki,Yajima, Torn,Sakamoto, Masami,Fujita, Tsutomu
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p. 1233 - 1240
(2007/10/03)
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- P-chirogenic α-carboxyphosphine boranes as effective pre-ligands in palladium-catalyzed asymmetric reactions
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P-Chirogenic α-carboxyphosphine boranes have been applied directly as pre-ligands in palladium-catalyzed asymmetric allylic alkylation and amination reactions, with in situ deprotection of the borane moiety. Using dimethylmalonate as the nucleophile afforded the alkylated product in up to 91% ee, while reaction with benzylamine gave amination in up to 94% ee. In both cases, the opposite enantiomer could be accessed in high ee by using the antipode of the ligand, easily accessible by exchanging (-)-sparteine for a (+)-sparteine mimic in the desymmetrization process used for preparing the ligands. Georg Thieme Verlag Stuttgart.
- Dolhem, Franck,Johansson, Magnus J.,Antonsson, Thomas,Kann, Nina
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p. 3389 - 3394
(2007/10/03)
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- A highly regioselective salt-free iron-catalyzed allylic alkylation
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(Chemical Equation Presented) Ironing out the kinks: A highly regioselective allylic alkylation can be performed in the presence of catalytic amounts of an iron(-II) complex and triphenylphosphane (see scheme; EWG = electron-withdrawing group). Allyl carbonates and pronucleophiles are coupled in high yields with a high regioselectivity comparable only with that obtained with Rh catalysts. The reaction is broadly applicable and does not require external base.
- Plietker, Bernd
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p. 1469 - 1473
(2007/10/03)
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- Chiral 2-(2-diphenylphosphinophenyl)-oxazolines: Synthesis and use in Pd-catalyzed asymmetric allylic alkylation
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The synthesis of 2-(2-diphenylphosphinophenyl)-oxazolines from o-fluoroben-zonitrile and (-)-norephedrine or (+)-endo-2-hydroxy-endo-3- aminobornane is described. The Pa-catalyzed alkylation of (E)-1,3-diphenylallyl acetate with the sodium salt of dimethy
- Ganchegui, Benjamin,Chevrin, Carole,Bouquillon, Sandrine,Le Bras, Jean,Henin, Francoise,Muzart, Jacques
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p. 2635 - 2639
(2007/10/03)
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- N-Heterocyclic carbenes as ligands in palladium-catalyzed Tsuji-Trost allylic substitution
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A Pd(0)-catalyzed allylic substitution (i.e., Tsuji-Trost reaction) using N-heterocyclic carbene as a ligand was investigated. It has been proven that an imidazolium salt 2d having bulky aromatic rings attached to the nitrogens in its imidazol-2-ylidene skeleton is suitable as a ligand precursor and that a Pd2dba3-imidazolium salt 2d-Cs2CO3 system is highly efficient for producing a Pd-NHC catalyst in this reaction. Allylic substitution using a Pd-NHC complex differed from that using a Pd-phosphine complex as follows: (1) the reaction using a Pd-NHC complex required elevated temperature (50 °C or reflux in THF), (2) allylic carbonates were inert to a Pd-NHC complex, and (3) nitrogen nucleophiles such as sulfonamide and amine did not react with allylic acetate. It was also found that allylic substitution with a soft nucleophile using a Pd-NHC catalyst proceeds via overall retention of configuration to give the product in a stereospecific manner, the stereochemical reaction course obviously being the same as that of the reaction using a Pd-phosphine complex.
- Sato, Yoshihiro,Yoshino, Taro,Mori, Miwako
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p. 5753 - 5758
(2007/10/03)
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- Synthesis and asymmetric catalytic application of chiral imidazolium-phosphines derived from (1R,2R)-trans-diaminocyclohexane
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Reaction between a chiral imidazole-amine precursor derived from (1R,2R)-trans-diaminocyclohexane and P1Cl (where P1 = PPh2, P(1,3,5-Me3C6H3)2, P(2,2′-O,O′-(1,1′-biphenyl), P((R)
- Hodgson, Richard,Douthwaite, Richard E.
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p. 5822 - 5831
(2007/10/03)
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- The preparation and resolution of 2-(2-pyridyl)- and 2-(2-pyrazinyl)- Quinazolinap and their application in palladium-catalysed allylic substitution
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The preparation and resolution of two new axially chiral quinazoline-containing phosphinamine ligands, 2-(2-pyridyl)-Quinazolinap and 2-(2-pyrazinyl)-Quinazolinap, is described. The ligands were synthesised in good yield over eight steps and included two
- Flanagan, Susan P.,Goddard, Richard,Guiry, Patrick J.
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p. 9808 - 9821
(2007/10/03)
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- Supraphos: A supramolecular strategy to prepare bidentate ligands
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Herein, we report a new strategy for the preparation of chelating bidentate ligands, which involves the mixing of two mondentate ligands functionalized with complementary binding sites. The assembly process is based on selective metal-ligand interactions
- Reek, Joost N.H.,R?der, Marc,Goudriaan, P. Elsbeth,Kamer, Paul C.J.,Van Leeuwen, Piet W.N.M.,Slagt, Vincent F.
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p. 4505 - 4516
(2007/10/03)
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- Scavenging and reclaiming phosphines associated with group 10 metal-mediated couplings
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(Equation Presented) Exposure of any of several mono- or bidentate phosphines to CuCl leads to quick removal of unwanted ligands from solution. Most phosphines, if desired, can be easily recovered.
- Lipshutz, Bruce H.,Frieman, Bryan,Birkedal, Henrik
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p. 2305 - 2308
(2007/10/03)
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- Asymmetric catalysis based on chiral phospholanes and hydroxyl phospholanes
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Chiral phosphine ligands derived from chiral natural products including D-mannitol and tartaric acid. The ligands contain one or more 5-membered phospholane rings with multiple chiral centers, and provide high stereoselectivity in asymmetric reactions.
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-
Page column 27-28
(2010/02/06)
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- New monodentate P,C-stereogenic bicyclic phosphanes: 1-Phenyl-1,3a,4,5,6, 6a-hexahydrocyclopenta[b]phosphole and 1-phenyl-octahydrocyclopenta[b]phosphole
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Racemic 1-phenyl-1,3a,4,5,6,6a-hexahydrocyclopenta[b]phosphole (4) was separated into enantiomerically pure 1-phenyl-1,3a,4,5,6,6a- hexahydrocyclopenta[b]phosphole 1-oxides [(RP)-6 and (S P)-6] by an oxidative resolution procedure in
- Pakulski, Zbigniew,Demchuk, Oleg M.,Frelek, Jadwiga,Luboradzki, Roman,Pietrusiewicz, K. Michal
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p. 3913 - 3918
(2007/10/03)
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- Non-C2-symmetrical antimony-phosphorus ligand, (R/S)-2-diphenylphosphano-2′-di(p-tolyl)stibano-1,1′-binaphthyl (BINAPSb): Preparation and its use for asymmetric reactions as a chiral auxiliary
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A new non-C2-symmetrical antimony-phosphorous ligand, (±)-2-diphenyl-phosphano-2′-di(p-tolyl)stibano-1, 1′-binaphthyl (BINAPSb) 3, has been prepared from 2-bromo-2′- diphenylphosphano-1,1′-naphthyl 4 via its borane complex 6, and could be resolved by the separation of a mixture of the diastereomeric palladium complexes 8A and 8B derived from the reaction of (±)-3 with optically active palladium reagent (S)-7. The enantiomerically pure BINAPSb 3 has proved to be highly effective in the palladium-catalyzed asymmetric hydrosilylation of styrene as a chiral auxiliary.
- Yasuike, Shuji,Kawara, Shin-Ichiro,Okajima, Satoru,Seki, Hiroko,Yamaguchi, Kentaro,Kurita, Jyoji
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p. 9135 - 9138
(2007/10/03)
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- Asymmetric allylic alkylation catalyzed by Pd(II)-complexes with (S)-BINPO, a hemilabile axially chiral P,O-heterodonor inducer
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A complex generated in situ from [Pd(η3-C3H 5)Cl]2 and (S)-BINPO 1 is an active catalyst in the asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl esters 6 via a malonate anion with ee's up to 81% being obtained. Rate and stereoselectivity of the reaction are dramatically influenced by the solvent. The Pd-complex [(S)-(BINPO)Pd(η3-1,3-diphenylallyl)] 5has been synthesized and its structure in the solid state determined by X-ray diffraction. The stoichiometric reaction of 5 with malonate anion affords the alkylated product of the same configuration as the one obtained in the catalytic reaction at room temperature in nearly identical enantiomeric purity (71%).
- Gladiali, Serafino,Taras, Rossana,Ceder, Rosa M.,Rocamora, Merce,Muller, Guillermo,Solans, Xavier,Font-Bardia, Merce
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p. 1477 - 1485
(2007/10/03)
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