Asymmetric synthesis of optically active alcohols with two chiral centres from a racemic aldehyde by the selective addition of dialkylzinc reagents using chiral catalysts
1991; Issue: 8 Linguagem: Inglês
10.1039/p19910002025
ISSN2050-8255
AutoresSeiji Niwa, Toshihiro Hatanaka, Kenso Soai,
Tópico(s)Asymmetric Synthesis and Catalysis
ResumoOptically active alcohols with two chiral centres have been obtained in good to high e.e.s (enantiomeric excesses) from racemic 2-phenylpropanal 1 by diastereo- and ena ntio-selective addition of dialkylzinc reagents using (1S,2R)-(–)-N,N-dibutylnorephedrine (DBNE) and (S)-(+)-diphenyl(1-methylpyrrolidin-2-yl)methanol (DPMPM) as chiral catalysts. It was found that in the presence of (1S,2R)-(–)-DBNE, dialkylzinc selectively attacked racemic 1 from the Si-face of the aldehyde 1 regardless of the configuration of 1 and that (S)-1 reacted faster with dialkylzinc than did (R)-1.
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