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DOI: 10.1055/s-2005-869891
Polymer-Supported Chiral Lewis Base Catalysts
Contributor(s): Yasuhiro Uozumi, Ray KawadeYokohama National University, Japan
Polystyrene with Chiral Phosphoramide Substituents as Lewis Base Catalysts for Asymmetric Addition of Allyltrichlorosilane: Enhancement of Catalytic Performance by Polymer Effect
Chem. Commun. 2005, 1857-1859
Publication History
Publication Date:
20 July 2005 (online)
Key words
asymmetric addition - allylation - Lewis bases - polymer effect
Significance
Novel polymer-supported chiral phosphoramides were used as a Lewis base catalyst 1 in the asymmetric addition of allyltrichlorosilane to benzaldehyde. The allylation of benzaldehyde proceeded in the presence of the catalyst 1 (10 mol% of phosphoramide unit) at -78 °C for six hours in dichloromethane to give 1-phenyl-but-3-en-1-ol in up to 84% yield with enantiomeric excesses of 63%. The reaction was accelerated by the addition of five equivalents of ethyldiisopropylamine. Catalyst 1 was found to be more effective its homogeneous counterpart.
Comment
This is the first report on the synthesis of polymers having chiral phosphoramides and their catalytic applications in asymmetric addition of allyltrichlorosilane to benzaldehyde.