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  • 1
    ISSN: 0947-6539
    Keywords: asymmetric catalysis ; hydrogenations ; palladium ; phosphorus ligands ; rhodium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optically active phosphorus ligands are widely used in homogeneous asymmetric catalysis. However, among the numerous available structures of this type, the subclass of optically active bisphosphines with at least one chiral phosphorus atom is rather underdeveloped. A bisphosphine with two chiral, nonracemizable bridgehead phosphorus centers, (meso,d/l)-2,2′,3,3′-tetraphenyl-4,4′,5,5′-tetramethyl-6,6′-bis-1-phosphanorborna-2,5-dienyl (BIPNOR), can be obtained by thermolysis of 1,1′-bisphospholyl with diphenylacetylene. Here, we report the resolution of the d/l isomer by means of a chiral palladium complex to give the two optically active forms of BIPNOR. We then investigate the catalytic properties of BIPNOR, incorporated in RhI and RuII catalysts for the hydrogenation of olefins and ketones and in a PdII catalyst for asymmetric alkylation reactions. BIPNOR is shown to give good results in these catalytic reactions.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 1091-1097 
    ISSN: 1434-193X
    Keywords: Phosphanorbornadiene ; Allylic metalation ; Allylic bromination ; BIPNOR dioxide ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -3-Methyl-substituted 1-phosphanorbornadiene oxides or sulfides such as 1a,b are either metalated by a strong base (n-BuLi or LDA) or brominated by NBS at the methyl substituent. The reaction of the resulting delocalised carbanions 2a,b takes place either at C-2 (H+, MeI) or at the methylene group (Me3SiCl, ClPPh2, I2). In the last case, γ-functional (5a,b or 6a,b) or bridged (7) phosphanorbornadienes are obtained. Similarly, the reaction of 3-bromomethyl-1-phosphanorbornadiene oxides such as 8 with nucleophiles [NaCH(CO2Me)2, PhO-, Me2NH, PhCH2NH2] yields the corresponding γ-functional phosphanorbornadienes 9-12. This chemistry has also been applied to the BIPNOR dioxide 13.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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