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  • 1
    Electronic Resource
    Electronic Resource
    Enantioselektive Katalyse, IX. Neue optisch reine 3,4-Bis(phosphanyl)pyrrolidine mit Phenyl-und Anisylgruppen sowie deren Palladium-und Rhodiumkomplexe (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 1091-1100 
    Details
    ISSN: 0009-2940
    Keywords: 3,4-Bis(phosphanyl)pyrrolidines ; Palladium complexes ; Rhodium complexes ; Asymmetric hydrogenation ; Phosphanes, chiral ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantioselective Catalysis, IX[1]. - New Optically Pure 3,4-Bis(phosphanyl)pyrrolidines with Phenyl and Anisyl Groups Including Their Palladium and Rhodium ComplexesMethods for the synthesis of the diastereomeric mixture of the [P(R,S),3R,4R,P′(R,S)]1-1-(tert1-butoxycarbonyl)1-3,4-bis[(2-methoxyphenyl)phenylphosphanyl]pyrrolidines (2a, b, c) are described. For the chromatographic separation and purification of the ligand diastereomers we transformed them into the PdI21-complexes (10a, b, c). The structure of (PR,3R,4R,P′R)1-1-(tert1-butoxycarbonyl)1-3,4-bis[(2-methoxyphenyl)phenylphosphanyl]pyrrolidine-P,P′}diiodopalladium (10 b) was determined by X-ray diffraction. Treatment of the palladium complexes with KCN yielded the pure phosphanes. The rhodium complexes (11a, 11b, 11c), which can be used as catalysts in enantioselective hydrogenations, were obtained by reaction of [Rh(COD)2]BF4 with compound 2a, 2b, or 2c.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260505
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  • 2
    Electronic Resource
    Electronic Resource
    Enantioselective Catalysis, XIIIPart XII: U. Nagel, J. Leipold, Chem. Ber., 1996, 129815-821.. Preparative and Structural Chemistry of Chiral 3-(Diphenylphosphanyl)-pyrrolidiens and Their Palladium(II) Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 385-398 
    Details
    ISSN: 0009-2940
    Keywords: Pyrrolidinephosphanes ; 3-Hydroxypyrrolidine ; 3-Diphenylphosphanylpyronlidine ; Salt effects ; Polymorphism ; Homogeneous catalysis ; Palladium ; Asymmetric catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of both enantiomers of 3-diphenylphosphanulpyrrolidiine (2) and several N-substituted derivatives together with two PdIi complexes of this ligand is reported. Form L-malic acid and L-hydroxyproline both enantiomers of 3-hydroxypyrrolidine are prepared without any problems due to epimerization. KPPh2 in the presence of LiCl is shown to be the most effective reagent for the synthesis of 2. The reported X-ray structure determination sof Pdl2 complexes show a rather rigid bicyclic hetero-norbornane skeleton. The flexibility of the other parts of the molecules is obvious in several polymorphs revealed by this method. This polymorphism is additionally investigated by a 31P-CP-MAS study. From solution 1-, 13C- and 31P-NMR studies it is concluded that the bicyclic hetero-norbornane skeleton is retained in solution.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300313
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  • 3
    Electronic Resource
    Electronic Resource
    Enantioselektive Katalyse, XI. Darstellung von optisch reinen Diphosphanen mit vier Stereozentren (1995)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 128 (1995), S. 309-316 
    Details
    ISSN: 0009-2940
    Keywords: 3,4-Bis(phosphanyl)pyrrolidines ; Palladium complexes ; Hydrogenation, asymmetric ; Phosphanes, chiral ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enantioselective Catalysis, XI. - Preparation of Optically Pure Diphosphanes with Four Stereogenic CentersWe synthesized a number of new diphosphanes with four stereogenic centers and two different aryl groups on each phosphorus atom. Starting with the diastereomeric mixture of [P(R,S),3R,4R,P′(R,S)]-1-(tert-butoxycarbonyl)-bis(phenyl-phosphanyl)pyrrolidine (1a,b,c) we prepared the corresponding chlorophosphanes by use of chlorotrimethylsilane followed by treatment with hexachloroethane. The chlorophosphanes react with Grignard. or organolithio compounds to the target molecules. For the chromatographic separation and purification of the diastereomers we transformed them into their Pdl2 complexes (Pd-4a,b,c to Pd-12a,b,c). The structures of Pd-4a, Pd-4c, Pd-6c, Pd-8b and Pd-9a were determined by X-ray diffraction analysis. A correlation between structural parameters of these Pd complexes and the enantio-selection for rhodium complexes of the same ligands as hydrogenation catalysts is suggested.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19951280316
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  • 4
    Electronic Resource
    Electronic Resource
    Enantioselective Catalysis, XIVPart XIII: U. Nagel, H. G. Nedden, Chem Ber. 1997, 130,385-397.Asymmetric Grignard Cross-Coupling Reaction: An Investigation of the Factors Influencing Asymmetric Induction with a New Type of Pyrrolidinephosphane (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 535-542 
    Details
    ISSN: 0009-2940
    Keywords: Cross-coupling ; Grignard reactions ; Pyrrolidinephosphanes ; Asymmetric amplification ; Gas chromatography ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An investigation of the asymmetric synthesis of 3-phenyl-1-butene by the Grignard cross-coupling reaction is presented. The reaction is catalysed by nickel complexes of bisphosphane and 3-diphenylphosphanylpyrrolidine-type ligands. A comparison of the results obtained with our P,N monophosphane ligands with those obtained with the most effective known amino acid derived P,N ligands shows a similar enantioselectivity but an inverse sense of optical induction. An X-ray structural analysis of the 1-phenylethyl Grignard compound is reported. Quantitative analysis and the determination of enantiomeric composition of the catalytic samples is accomplished using a novel enantioselective GLC separation. Compared to the popular model reaction that uses a chloride-containing Grignard compound and vinyl bromide as starting compounds, we obtain improved enantioselectivities of P,N monophosphane catalysts by substituting vinyl bromide with vinyl chloride. With two of the new P,N ligands we find a nonlinear dependence of enantioselectivity on the enantiomeric purity of the ligands (asymmetric amplification). Catalytic results subject to such nonlinear effects show a dependence on the ligand to nickel ratio.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300414
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  • 5
    Electronic Resource
    Electronic Resource
    Metallorganische Lewis-Säuren, XLVIII. Neue Vorläufer metallorganischer, kationischer Lewis-Säuren mit zwei freien Koordinationsstellen: (OC)4Re(OEt2)FBF3 und (OC)2(PPh3)2Ru(FBF3)2 (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 927-932 
    Details
    ISSN: 0009-2940
    Keywords: Lewis acids, organometallic ; 14e- Systems ; Allyl complexes ; Rhenium complexes ; Ruthenium complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organometallic Lewis Acids, XLVIII[1]. - New Precursors to Organometallic Cationic Lewis Acids with two Accessible Coordination Sites: (OC)4Re(OEt2)FBF3 and (OC)2 (PPh3)2Ru(FBF3)2The allyl transfer reaction between Re(CO)5- and [(η31-allyl)PdCl]2 complexes leads to (allyl)rhenium complexes (η31-H2CCR1CR2R3) Re(CO)4 (1: R1, R2, R3=H; 2; R2, R3=H, R1=Me; 3: R1, R2=H, R3=Me; 4: R1=H, R2, R3=Me). The 2-methylallyl complex 2 has been characterized by low-temperature X-ray diffraction. Protonation of 1 with HBF4 · OEt2 in CH2Cl2 gives the complex (OC)4Re(OEt2)FBF3 (5), which is a precursor for the 14 e- System “(OC)4Re+”. THF and H2O replace the diethyl ether in 5 to give [(OC)4Re(solvent)2]BF4 (6, 7). The reaction of (OC)2(PPh3)2RuCl2 with AgBF4 yields the complex (OC)2 (PPh3)2Ru(FBF3)2 (8), which can be considered as a precursor for the 14 e- cation “(OC)2 (PPh3)2Ru2+” and reacts with H2O to give [(OC)2 (PPh3)2Ru(F)(H2O)]BF4 (9). Complexes 5-9 are characterized by IR, 1H-, 13C-, 31P-and 19F-NMR spectroscopy.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260412
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