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  • Synthesis, extraction abili...
    Bakó, Péter; Vízvárdi, Kristóf; Toppet, Suzanne; Van der Eycken, Erik; Hoornaert, Georges J.; Tõke, László

    Tetrahedron, 12/1998, Volume: 54, Issue: 49
    Journal Article

    A number of new chiral monoaza-15-crown-5 derivatives ( 4–9) and lariat ethers ( 10–15) anellated to phenyl-β-D-glucopyranoside have been synthesized. Their extracting ability was measured with alkali metal (Li, Na, K) and ammonium cations. The derivatives show significant asymmetric induction as phase transfer catalysts in the Michael addition of 2-nitropropane to chalcone (82% ee) although in low yield, and in the Darzens condensation of phenacyl chloride with benzaldehyde (74% ee). The substituent at the nitrogen atom of the crown ethers has a major influence on both the extraction ability and the enantioselectivity. Crown ethers anellated to phenyl-β-D-glucopyranoside have been used as catalyst in two enantioselective carbon-carbon bond forming reaction s: the Michael addition of 2-nitropropane to chalcone (e.e.: 82%) and the Derzens condensstion of phenacyl chloride with benzaldehyde (e.e.: 74%).