- Cyclization of o-Allylstyrene via Hydrosilylation: Mechanistic Aspects of Hydrosilylation of Styrenes Catalyzed by Palladium-Phosphine Complexes
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Hydrosilylation of o-allylstyrene with trichlorosilane in the presence of 0.3 mol % of a palladium catalyst bearing triphenylphosphine gave trans-1-methyl-2-(trichlorosilylmethyl)indan, l-(2-(2-propenyl)phenyl)-1-trichlorosilylethane, and 1-(2-((E)-1-propenyl)phenyl)-1-trichlorosilylethane. The reaction of styrene with trichlorosilane gave a quantitative yield of 1-phenyl-1-(trichlorosilyl)ethane while allylbenzene did not give silylation products under the same reaction conditions. These results show that the hydropalladation process is operative in the hydrosilylation of styrene derivatives with trichlorosilane catalyzed by palladium-phosphine complexes.
- Uozumi, Yasuhiro,Tsuji, Hayato,Hayashi, Tamio
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Read Online
- Polymer supported ferrocene derivatives. Catalytic hydrosilylation of olefins by supported palladium and platinum complexes
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Platinum and palladium derivatives of polymers functionalized with the ferrocene derivatives 1-ferrocenylethyldimethylamine (3), 1,1'-bis(diphenylphosphino)ferrocene (4), N,N-dimethyl-1-(2-diphenylphosphinoferrocenyl)ethylamine (5), and (S,R)-5 are effective catalysts for the hydrosilylation of olefins such as styrene and 1-hexene by trichlorosilane.They can be recycled with no loss of activity.The palladium derivatives catalyze stereoselective α-addition to styrene and the optical yield using (S,R)-5 is 15.2percent.The stereoselectivity remains the same but the optical yield drops on recycling.All other reactions studied result in addition to the terminal carbon atom of the olefin.The absence of ligand effects indicates that the platinum derivatives are reduced to catalytically active metal.The method used for the binding of chiral 5 to the polymer probably results in the induction of chirality at the linking carbon atom, polymer-*CHOH-(ferrocene derivative).
- Cullen, William R.,Han, Nam Fong
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Read Online
- Homogeneous Palladium-Catalyzed Selective Reduction of 2,2′-Biphenols Using HCO 2H as Hydrogen Source
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An efficient homogeneous palladium-catalyzed selective deoxygenation of 2,2′-biphenols by reduction of aryl triflates with HCO 2H as the hydrogen source is reported. This protocol complements the current method based on heterogeneous Pd/C-catalyzed hydrogenation with hydrogen gas. This process provided the reduction products in good to excellent yields, which could be readily converted to various synthetically useful molecules, especially ligands for catalytic synthesis.
- Li, Ruoling,Li, Chenchen,Yang, Wen,Zhao, Wanxiang
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p. 1605 - 1618
(2021/02/01)
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- Axially Chiral Biaryl Monophosphine Oxides Enabled by Palladium/WJ-Phos-Catalyzed Asymmetric Suzuki-Miyaura Cross-coupling
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A highly enantioselective palladium/WJ-Phos-catalyzed Suzuki-Miyaura coupling reaction for efficient construction of axially chiral biaryl monophosphine oxides was developed. A series of axially chiral biaryl monophosphine oxides were obtained in good yields and with high enantioselectivities. The practicability of this reaction was validated in the straightforward synthesis of axially chiral biaryl monophosphine ligand and demonstrated by a 100-g-scale synthesis. Moreover, various functionalizations of the product make it as a platform molecule for synthesis of other chiral biaryl phosphines.
- Ji, Wangqin,Wu, Hai-Hong,Zhang, Junliang
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p. 1548 - 1554
(2020/02/04)
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- METALLATED BENZYLSILANES AND THEIR USE AS POLYMERIZATION INITIATORS
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The invention relates to novel compounds useful as polymerization initiators or precursors for polymerization initiators. The invention further relates to a method of making the polymerization initiators and resulting polymers. The invention also relates
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Page/Page column 31
(2018/09/12)
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- Asymmetric Synthesis of Axially Chiral 2-Aminobiaryls by Rhodium-Catalyzed Benzannulation of 1-Arylalkynes with 2-(Cyanomethyl)phenylboronates
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Asymmetric benzannulation of 1-arylalkynes, where the aryl group is an ortho-substituted aromatic group, with 2-(cyanomethyl)phenylboronate was catalyzed by a rhodium complex coordinated with a chiral diene ligand to give high yields of axially chiral 2-aminobiaryls with greater than 90 % ee.
- Xue, Fei,Hayashi, Tamio
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supporting information
p. 10368 - 10372
(2018/07/31)
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- Kinetic Resolution of Planar-Chiral Ferrocenylphosphine Derivatives by Molybdenum-Catalyzed Asymmetric Ring-Closing Metathesis and Their Application in Asymmetric Catalysis
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Highly enantioselective kinetic resolution of racemic planar-chiral metallocenylphosphine sulfides was realized by the molybdenum-catalyzed asymmetric ring-closing metathesis reaction with the krel values of up to 147. The enantiomerically enriched 1,4-but-2-enylene-bridged ferrocenylphosphine sulfides thus obtained could be purified to enantiomerically pure forms by simple recrystallization from hot methanol, and subsequent reduction of the phosphine sulfides provided the corresponding planar-chiral phosphines with retention of the enantiomeric homogeneity. This is a rare example of preparing planar-chiral ferrocenylphosphines by catalytic asymmetric reactions. The single-enantiomer planar-chiral ferrocenylphosphines were applied as chiral ligands in the rhodium-catalyzed asymmetric 1,4-addition reaction (the Hayashi-Miyaura conjugate addition reaction) of phenylboronic acid to 2-cyclohexenone to show excellent enantioselectivity and high yields. The NMR studies clarified that the butenylene-bridged ferrocenylphosphine coordinated to a rhodium(I) cation in a monodentate fashion and an interaction of the bridging olefin moiety to the rhodium atom was not detected.
- Ogasawara, Masamichi,Arae, Sachie,Watanabe, Susumu,Nakajima, Kiyohiko,Takahashi, Tamotsu
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p. 1308 - 1315
(2016/02/18)
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- The design of second generation MOP-phosphonites: Efficient chiral hydrosilylation of functionalised styrenes
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A series of enantiopure MOP-phosphonite ligands, with tailored steric profiles, have been synthesised and are proven to be very successful in high-yielding, regio- and enantioselective catalytic hydrosilylation reactions of substituted styrenes, affording important chiral secondary alcohols.
- Fleming, James T.,Ficks, Arne,Waddell, Paul G.,Harrington, Ross W.,Higham, Lee J.
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supporting information
p. 1886 - 1890
(2016/02/09)
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- When Chirality Meets “Buchwald-Type” Phosphines: Synthesis and Evaluation in Frustrated Lewis Pair-, Lewis Base- and Palladium-Promoted Asymmetric Catalysis
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We describe the synthesis of axially chiral “Buchwald ligand”-like biphenylphosphines in highly enantioenriched form. These monodentate phosphines, biphenyl analogues of Hayashi's MOP ligands, were evaluated in phosphine-promoted organocatalysis and in hydrosilylations catalyzed by palladium or by frustrated Lewis pairs. As expected, the title phosphines appeared best suited for transition metal catalysis where they provided higher asymmetric induction.
- Fer, Micka?l J.,Cinqualbre, Joséphine,Bortoluzzi, Julien,Chessé, Matthieu,Leroux, Frédéric R.,Panossian, Armen
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p. 4545 - 4553
(2016/09/23)
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- Asymmetric Suzuki-Miyaura cross-coupling for the synthesis of chiral biaryl compounds as potential monophosphine ligands
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Efficient asymmetric Suzuki-Miyaura coupling reactions have been employed for the first time to synthesize chiral biaryl compounds with phosphinate groups as chiral auxiliaries. A series of functionalized chiral biaryls are thereby synthesized in excellent yields and good diastereoselectivities (up to >95:5 d.r.) and axially chiral monophosphorus ligands are obtained through further functionalizations.
- Ma, Yan-Na,Yang, Shang-Dong
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p. 6673 - 6677
(2015/04/27)
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- ACTIVATED HALO-CONTAINING ARALKYLSILANE
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The invention is directed to an activated halo-containing aralkylsilanes possessing at least one hydrolyzable group bonded to a silicon atom and at least one halo functional group bonded to a carbon atom to which both the silicon atom and an aromatic grou
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Paragraph 0090
(2016/01/12)
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- Air-stable chiral primary phosphines: A gateway to MOP ligands with previously inaccessible stereoelectronic profiles
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The air-stable chiral primary phosphines 1a,b facilitate the synthesis of previously inaccessible or hard-to-access chiral MOP-type ligands 2a,b-5a,b, which can be prepared in one-pot reactions. These derivatives have been prepared to allow for a unique comparison of their differing structural and electronic profiles, determined here by a number of experimental and theoretical studies. Phosphiranes 2a,b and phosphonites 5a,b are electron-poor compounds, with the former possessing exceptional thermal stability. Conversely, the dimethylarylphosphines 3a,b and bis(dimethylamino)arylphosphines 4a,b are good electron donors, and, in contrast to earlier reports, the dialkylarylphosphines were found to be remarkably air-stable. The ligands were coordinated to platinum(II), and the weak trans-influence of the highly strained phosphiranes 2a,b was revealed both in solution and in the solid state. The steric parameters of the ligands were investigated by the allyl rotation of their methallylpalladium(II) complexes, which showed subtle differences in exchange rates. Aryl side-on coordination of the MOP-backbone to palladium(II) was observed for complexes with a non-coordinating counterion and structurally analyzed in the case of ligand 4b. The asymmetric induction and catalytic activity of 2a,b-5a,b were tested in the hydrosilylation of styrene as well as the allylic alkylation of (rac)-(E)-1,3-diphenylallyl acetate. Major differences in reactivity were related back to the electronic parameters of the ligands.
- Ficks, Arne,Clegg, William,Harrington, Ross W.,Higham, Lee J.
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p. 6319 - 6329
(2015/02/19)
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- Synthesis and evaluation of P-chirogenic monodentate binaphthyl phosphines
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P-Chirogenic monodentate binaphthyl phosphines were prepared in five steps from enantiomerically pure BINOL. This approach supposes the utilization of two methods previously developed in our group, the formation of secondary phosphine oxide, and the reduction of tertiary phosphine oxide using the association of tetramethyldisiloxane and Ti(OiPr)4. During the last reduction step, only the formation of the more stable diastereoisomer was observed. This product was employed as a ligand for the palladium catalyzed hydrosilylation of styrene to afford the corresponding alcohol with high yield and enantiomeric excess.
- Duclos, Marie-Christine,Singjunla, Yuttapong,Petit, Christelle,Favre-Reguillon, Alain,Popowycz, Florence,Metay, Estelle,Lemaire, Marc,Jeanneau, Erwann
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p. 5984 - 5986,3
(2020/08/20)
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- MOP-phosphonites: A novel ligand class for asymmetric catalysis
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Chiral phosphonite ligands (S,Rb)-5a, (S,Sb)-5b, (R,Rb)-6a and (R,Sb)-6b are introduced, comprising a MOP-type backbone with a binol-based binaphthyl group bound to the phosphorus. Their reaction with [Pd(η3-C4H7)Cl] 2 affords η3-methallylpalladium chloride complexes 7a/b and 8a/b which have been isolated and structurally characterised. Solid-state and solution studies indicate subtle differences in their coordination behaviour, which ultimately affects their efficacy in the asymmetric hydrosilylation of styrene. The Royal Society of Chemistry 2012.
- Ficks, Arne,Hiney, Rachel M.,Harrington, Ross W.,Gilheany, Declan G.,Higham, Lee J.
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supporting information; experimental part
p. 3515 - 3522
(2012/05/04)
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- SATURATED N-HETEROCYCLIC CARBENE-LIGAND METAL COMPLEX DERIVATIVES, PREPARING METHOD THEREOF, AND PREPARING METHOD OF SILANE COMPOUND BY HYDROSILYLATION REACTION USING THE SAME AS CATALYST
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Provided are a saturated N-heterocyclic carbene-ligand metal complex derivative, a method for preparing the same, and a method for preparing a silane compound by hydrosilylation using the same as a catalyst. To describe in more detail, the metal complex derivative has a saturated N-heterocyclic carbene derivative and an olefin ligand at the same time. A silane compound is prepared by hydrosilylation in the presence of the metal complex derivative as a catalyst. The provided metal complex derivative of the present invention has superior stability during hydrosilylation reaction and is capable of effectively performing the hydrosilylation reaction at low temperature even with small quantity. Further, a product with superior regioselectivity may be obtained. In addition, after the hydrosilylation reaction is completed, the metal complex derivative may be recovered and recycled.
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Page/Page column 9; 10
(2011/07/08)
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- SATURATED N-HETEROCYCLIC CARBENE-LIGAND METAL COMPLEX DERIVATIVES, PREPARING METHOD THEREOF, AND PREPARING METHOD OF SILANE COMPOUND BY HYDROSILYLATION REACTION USING THE SAME AS CATALYST
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Provided are a saturated N-heterocyclic carbene-ligand metal complex derivative, a method for preparing the same, and a method for preparing a silane compound by hydrosilylation using the same as a catalyst. To describe in more detail, the metal complex derivative has a saturated N-heterocyclic carbene derivative and an olefin ligand at the same time. A silane compound is prepared by hydrosilylation in the presence of the metal complex derivative as a catalyst. The provided metal complex derivative of the present invention has superior stability during hydrosilylation reaction and is capable of effectively performing the hydrosilylation reaction at low temperature even with small quantity. Further, a product with superior regioselectivity may be obtained. In addition, after the hydrosilylation reaction is completed, the metal complex derivative may be recovered and recycled.
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Page/Page column 16-18
(2011/07/30)
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- Taming functionality: Easy-to-handle chiral phosphiranes
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Enantiopure chiral phosphiranes possessing a binaphthyl backbone demonstrate remarkable thermal stability, are highly resistant to air-oxidation and are effective ligands in catalytic asymmetric hydrosilylations.
- Ficks, Arne,Martinez-Botella, Ivan,Stewart, Beverly,Harrington, Ross W.,Clegg, William,Higham, Lee J.
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supporting information; experimental part
p. 8274 - 8276
(2011/09/14)
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- High-molecular-weight polyquinoxaline-based helically chiral phosphine (PQXphos) as chirality-switchable, reusable, and highly enantioselective monodentate ligand in catalytic asymmetric hydrosilylation of styrenes
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A polyquinoxaline-based helical polymer ligand bearing both helical-sense-determining chiral side chains and coordinating diarylphosphino side chains exhibits solvent-dependent formation of P- or M-helical structures, with which either the S- or R-hydrosilylation product was obtained with high (>93% enantiomeric excess) enantioselectivities.
- Yamamoto, Takeshi,Yamada, Tetsuya,Nagata, Yuuya,Suginome, Michinori
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supporting information; experimental part
p. 7899 - 7901
(2010/08/05)
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- ACTIVATED HALO-CONTAINING ARALKYLSILANE COMPOSITION, PROCESS OF PREPARING SAME AND RUBBER COMPOSITIONS MADE THEREFROM
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The invention is directed to an activated halo-containing aralkylsilanes possessing at least one hydrolyzable group bonded to a silicon atom and at least one halo functional group bonded to a carbon atom to which both the silicon atom and an aromatic group are covalently bonded. The invention is also directed to a process for making such a silane as well as its use in rubber compositions and articles containing such rubber compositions, such as tires.
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- Helical poly(quinoxaline-2,3-diyl)s bearing metal-binding sites as polymer-based chiral ligands for asymmetric catalysis
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Living it up: Helical polyquinoxalines with single and multiple metal-binding sites, prepared by living polymerization of o-diisocyanobenzenes, are used in the asymmetric hydrosilylation of styrenes, resulting in comparable enantioselectivities to those obtained by low-molecular-weight catalyst systems (up to 87% ee, stereochemistry was determined by a chiral initiator) and a turnover number of almost 1000. (Chemical Equation Presented).
- Yamamoto, Takeshi,Suginome, Michinori
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scheme or table
p. 539 - 542
(2009/04/14)
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- Synthesis of the first C2-asymmetric phosphinine and its pyrylium precursor
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The synthesis of the first C2 chiral phosphinine (phosphabenzene) and its pyrylium salt precursor is reported. The chiral phosphinine is derived from (+)-camphor, is a crystalline air-stable solid and is shown to effectively form complexes with metals. A preliminary result using the phosphinine as a ligand for asymmetric catalysis is reported and rationalized structurally.
- Bell, Jason R.,Franken, Andreas,Garner, Charles M.
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experimental part
p. 9368 - 9372
(2009/12/28)
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- Synthesis and application of bulky phosphoramidites: Highly effective monophosphorus ligands for asymmetric hydrosilylation of styrenes
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A series of bulky monodentate phosphoramidite ligands were synthesized from chiral 3,3′-diaryl substituted BINOL derivatives and achiral or dendritic amines in good yields. Asymmetric hydrosilylation of styrenes with trichlorosilane in the presence of palladium complexes of these bulky ligands gave chiral silanes in high yields with excellent activity and productivity. Oxidation of these chiral silanes with hydrogen peroxide gave the corresponding chiral secondary alcohols in up to 96% ee.
- Zhang, Feng,Fan, Qing-Hua
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experimental part
p. 4470 - 4474
(2009/12/25)
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- Asymmetric hydrosilylation of styrenes by use of new chiral phosphoramidites
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New chiral phosphoramidites were synthesized from chiral unsymmetrical amines and BINOL in good yields. Enantioselective hydrosilylation of styrenes with trichlorosilane in the presence of palladium complexes of these ligands provided chiral silanes in medium to high yields. Oxidation of these chiral silanes with hydrogen peroxide gave the corresponding chiral secondary alcohols in up to 97% ee. Georg Thieme Verlag Stuttgart.
- Li, Xinsheng,Song, Jianan,Xu, Dongcheng,Kong, Lichun
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p. 925 - 931
(2008/12/20)
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- Novel optically active biaryl phosphorus compound and production process thereof
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The invention provides a novel optically active biaryl phosphorus compound that can be produced easily without the step of optical resolution, which is almost indispensable step in a conventional method. A phosphorus compound defined by the following general formula (1): in the formula (1), R1 denotes a hydrogen atom or a hydroxy protective group; R2 denotes a group defined by the following formula (R2-1) or (R2-2); R3, R4, R5, and R6 may be the same or different and independently denote a hydrogen atom, an alkyl group, an alkoxy group, an acyloxy group, a halogen atom, a haloalkyl group, or a dialkylamino group; two among R3, R4, R5, and R6 may form an aromatic ring optionally having a substituent group, and two among R3, R4, R5, and R6 may form a methylene chain optionally having a substituent group or a (poly)methylenedioxy group optionally having a substituent group: in the formula (R2-1) and (R2-2), R7 denotes an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, or an aryloxy group; R8 and R9 independently denote a hydrogen atom, an alkyl group, or an aryl group; z denotes a divalent group; and a denotes an integer of 0 or 1.
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Page/Page column 16-17
(2008/12/06)
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- A versatile approach to planar chiral monophosphane ligands
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The enantioselective reaction of a chiral bisamide and an electrophile with benzyl ether complexes of arene tricarbonyl chromium(0) was used to introduce the asymmetry into a synthesis of novel enantiopure planar chiral ligands. Elaboration of the resulting ether complexes [η6-4-t-BuC 6H4CHE1(OR)]Cr(CO)3 via a diastereo-selective ortholithiation/chlorophosphane quench protocol led to the synthesis of planar chiral monophosphane complexes with high enantiomeric purity (typically 96-98% ee) for assessment in the palladium-catalyzed asymmetric hydrosilylation of styrene. The identity of benzylic substituent E1 (installed using the chiral base reaction) was found to have a significant effect on the enantioselectivity of resulting catalysts. Removal of the tricarbonylchromium(0) unit from the structurally optimized phosphane ligand was accomplished using a high-yielding borane protection-aerial oxidation-deprotection strategy. Georg Thieme Verlag Stuttgart.
- Gibson, Susan E.,Rendell, Jacob T.,Rudd, Matthew
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p. 3631 - 3638
(2008/03/13)
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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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- OPTICALLY ACTIVE PHOSPHITES AND PHOSPHORAMIDITES BEARING BIPHENOL SKELETONS WITH AXIAL CHIRALITY, AND THEIR USE IN CATALYTIC ASYMMETRIC REACTIONS
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Novel optically active ligands which are mondentate phosphites and phosphoramidites, and bidentate phosphites and phosphoramidites; optically active catalysts comprising a reaction mixture of the ligand and a transition metal or its compound; and processes of using the optically active catalysts to produce optically active compounds.
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Page/Page column 76-77
(2010/12/01)
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- Synthesis and application of arylmonophosphinoferrocene ligands: ultrafast asymmetric hydrosilylation of styrene.
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A short and efficient synthetic route to a novel class of atropisomeric and planar chiral 2-aryl-1-diphenylphosphanylferrocene ligands is presented. The modular design of the ligands allows a synthetic approach in which both the aromatic moiety and the phosphino substituent can be varied easily. This permits fine-tuning of steric and electronic properties. The ligands have been tested in the asymmetric hydrosilylation of styrene where enantioselectivities up to 90% are obtained. Optimization of the palladium-to-ligand ratio resulted in hitherto unparalleled turnover frequencies (TOF) exceeding 180 000 h(-1). The absolute stereochemistry of the ligands was determined from an X-ray structure. 2D NMR experiments in combination with ab initio calculations were used to assign the conformation of the atropisomeric biarylic scaffold.
- Pedersen, Henriette Lodberg,Johannsen, Mogens
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p. 7982 - 7994
(2007/10/03)
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- Asymmetric hydrosilylation of styrenes catalyzed by palladium-MOP complexes: Ligand modification and mechanistic studies
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In the palladium-catalyzed asymmetric hydrosilylation of styrene (3a) with trichlorosilane, several chiral monophosphine ligands, (R)-2-diarylphosphino-1,1′-binaphthyls (2a-g), were examined for their enantioselectivity. The highest enantioselectivity was observed in the reaction with (R)-2-bis[3,5-bis(trifluoromethyl)phenyl]phosphino-1, 1′-binaphthyl (2g), which gave (S)-1-phenylethanol (5a) of 98% ee after oxidation of the hydrosilylation product, 1-phenyl-1-(trichlorosilyl)ethane (4a). The palladium complex of 2g also efficiently catalyzed the asymmetric hydrosilylation of substituted styrenes on the phenyl ring or at the β position to give the corresponding chiral benzylic alcohols of over 96% ee. Deuterium-labeling studies on the hydrosilylation of regiospecifically deuterated styrene revealed that β-hydrogen elimination from 1-phenylethyl(silyl)palladium intermediate is very fast compared with reductive elimination giving hydrosilylation product when ligand 2g is used. The reaction of o-allylstyrene (9) with trichlorosilane catalyzed by (R)-2g/Pd gave (1S,2R)-1-methyl-2-(trichlorosilylmethyl)indan (10) (91% ee) and (S)-1-(2-(propenyl)phenyl)-1-trichlorosilylethanes (11a and 11b) (95% ee). On the basis of their opposite configurations at the benzylic position, a rationale for the high enantioselectivity of ligand 2g is proposed.
- Hayashi,Hirate,Kitayama,Tsuji,Torii,Uozumi
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p. 1441 - 1449
(2007/10/03)
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- Modification of chiral monodentate phosphine (MOP) ligands for palladium-catalyzed asymmetric hydrosilylation of styrenes
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In the palladium-catalyzed asymmetric hydrosilylation of styrene with trichlorosilane, several chiral monophosphine ligands, (R)-2-diarylphosphino-1,1′-binaphthyls (2), were examined for their enantioselectivity. The highest enantioselectivity was observed in the reaction with (R)-2-bis[3,5-bis-(trifluoromethyl)phenyl]phosphino-1,1′-binaphthyl (2g) , which gave (S)-1-phenylethanol of 98% ee after oxidation of the hydrosilylation product.
- Hayashi, Tamio,Hirate, Seiji,Kitayama, Kenji,Tsuji, Hayato,Torii, Akira,Uozumi, Yasuhiro
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p. 1272 - 1273
(2007/10/03)
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- Method of making an aromatic chlorosilane compound by a hydrosilation reaction
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A process comprising the hydrosilation of an aromatic vinyl compound by a hydridochlorosilane compound in the present of platinum or platinum compound and a carboxylic acid. The process favors the formation of the β-adduct of the hydrosilation reaction.
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- Enantioposition-selective arylation of biaryl ditriflates by palladium- catalyzed asymmetric Grignard cross-coupling
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Asymmetric cross-coupling of achiral biaryl ditriflates with aryl Grignard reagents in the presence of 1 equiv of lithium bromide and 5 tool % of palladium complex PdCl2[(S)-alaphos], where alaphos stands for (2- dimethylamino)propyldiphenylphosphine, gave axially chiral monophenylation products with high enantioposition-selectivity. The remaining triflate group in the monophenylation products was substituted with carboxyl and diphenylphosphino groups through palladium-catalyzed carbonylation and diphenylphosphinylation, respectively.
- Kamikawa, Takashi,Hayashi, Tamio
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p. 3455 - 3466
(2007/10/03)
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- Synthesis and first application of a new family of monophosphine ferrocene ligands (MOPF)
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A new family of monophosphine ferrocene ligands (MOPF) has been synthesised in two steps from an optically pure ferrocenyl sulfoxide and the first preliminary studies employing these ligands in asymmetric hydrosilylation of styrene are presented.
- Pedersen, Henriette L.,Johannsen, Mogens
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p. 2517 - 2518
(2007/10/03)
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- Optically active tertiary phosphine compound, transition metal complex comprising the same as ligand and process for preparing optically active organic silicon compound using said transition metal complex
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A tertiary phosphine compound of the formula (1): STR1 in which R1 and R1' are hydrogen atoms or together form --CH=CH--CH=CH--; R2 and R3 together form a group of the formula (a): STR2 in which --.circle-solid. represent a bond to be bonded to the R3 group, and --? represents a bond to be bonded to the R2 group when R1 and R1 ' together form --CH=CH--CH=CH--, or when R1 is a hydrogen atom, R2 and R3 together form --CH=CH--CH=CH-- or R2 is a hydrogen atom and R3 is a substituted or unsubstituted alkyl group, or a substituted or unsubstituted phenyl group; A1 is a 3-trifluoromethylphenyl group or a 3,5-bis(trifluoromethyl)phenyl group when R1 is a hydrogen atom and R2 and R3 together form --CH=CH--CH=CH--, or a substituted or unsubstituted phenyl group when R1 is not a hydrogen atom or when R2 and R3 do not together form --CH=CH--CH=CH--.
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- Assessment of the activity of 8'diphenylphosphino-8'-methoxy-1,1'- binaphthyl as a ligand for palladium-catalyzed reactions
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A monodentate phosphine, 8-diphenylphosphino-8'-methoxy-1,1'-binaphthyl, was shown to be active as a ligand in palladium-catalyzed reactions, including the reduction of allylic carbonates with formic acid, hydrosilylation of a terminal olefin, and hydroboration of but-1-en-3-yne, even though it has a highly hindered lone pair.
- Fuji, Kaoru,Sakurai, Minoru,Kinoshita, Takayoshi,Tada, Toshiji,Kuroda, Akio,Kawabata, Takeo
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p. 1524 - 1526
(2007/10/03)
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- Palladium-catalysed Asymmetric Hydrosilylation of Styrenes with a New Chiral Monodentate Phosphine Ligand
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Asymmetric hydrosilylation of styrenes (ArCH=CHR) with trichlorosilane in the presence of a palladium catalyst (0.1 molpercent) bearing a new chiral monodentate phosphine ligand, (S)-2-diphenylphosphino-1,1'-binaphthyl , followed by oxidation of the resulting 1-aryl-1-silylalkanes, gives optically active benzylic alcohols of up to 96percent enantiomeric excess (e.e.).
- Kitayama, Kenji,Uozumi, Yasuhiro,Hayashi, Tamio
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p. 1533 - 1534
(2007/10/02)
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- Synthesis of (β-N-sulfonylaminoalkyl)phosphines and their use in palladium-mediated asymmetric synthesis
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A series of (β-N-sulfonylaminoalkyl)phosphine ligands has been developed and employed for asymmetric palladium-catalyzed hydrosilylation and Heck-type hydroarylation, affording up to 72% ee and 90% yield.
- Sakuraba,Okada,Morimoto,Achiwa
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p. 927 - 934
(2007/10/02)
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- Regio- and Enantioselective Hydrosilylation of 1-Arylalkenes by Use of Palladium-MOP Catalyst
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Hydrosilylation of styrenes bearing β-substituents with trichlorosilane was catalyzed by a palladium complex (0.1 mol percent) coordinated with (R)-2-methoxy-2'-diphenylphosphino-1,1'-binaphthyl ((R)-MeO-MOP) to give high yields of optically active 1-aryl-1-silylalkanes (80-85percent ee) as single regioisomers.The resulting silanes were readily converted into the corresponding optically active alcohols (80-99percent yield).
- Uozumi, Yasuhiro,Kitayama, Kenji,Hayashi, Tamio
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p. 2419 - 2422
(2007/10/02)
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- Asymmetric Hydrosilylation of Cyclopentadiene and Styrene with Chlorosilanes Catalyzed by Palladium Complexes of Chiral (β-N-Sulfonylaminoalkyl)phosphines
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It was found that the palladium complexes of newly prepared chiral (β-aminoalkyl)phosphine derivatives bearing N-sulfonyl groups were efficient catalysts for asymmetric hydrosilylations of cyclopentadiene and styrene with chlorosilanes.
- Okada, Toshimi,Morimoto, Toshiaki,Achiwa, Kazuo
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p. 999 - 1002
(2007/10/02)
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