129647-85-4Relevant academic research and scientific papers
Asymmetric Synthesis of Alcohols with Two Chiral Centres from a Racemic Aldehyde by the Selective Addition of Dialkylzinc Reagents using (1S,2R)-(-)-N,N-Dibutylnorephedrine and (S)-(+)-Diphenyl-(1-methylpyrrolidin-2-yl)methanol as Chiral Catalysts
Soai, Kenso,Niwa, Seiji,Hatanaka, Toshihiro
, p. 709 - 711 (1990)
Optically active alcohols with two chiral centers were obtained in up to 93percent enantiomeric excess by the selective addition of dialkylzinc reagents to the racemic aldehyde, 2-phenylpropanal, using the title compounds as chiral catalysts.
Solvent and temperature effects on diastereofacial selectivity: Amines as co-solvents in n-butyllithium addition to α-chiral aldehydes
Cainelli, Gianfranco,Giacomini, Daria,Galletti, Paola,Quintavalla, Arianna
, p. 1993 - 2000 (2003)
Temperature-dependent selectivity in nucleophilic additions to α-chiral aldehydes is affected by solvent mixtures. In this context, we investigated the effect on diastereoselectivity of tertiary amines as co-solvents. Addition of 5 mol% of an amine to hexane strongly influences the anti/syn ratio in the additions of nBuLi to 2-phenylpropanal and to (2S)-2-[(tertbutyl)dimethylsilyloxy]-2-propanal. In these hexane/amine mixtures as reaction solvents, we observed diastereoselectivities higher than those obtained in hexane. In the corresponding Eyring plots of ln(anti/syn) against the reciprocal temperature, we observed inversion temperatures (Tinv), these generally occurring at higher temperatures in the hexane/amine mixtures than in pure hexane. The presence of the inversion temperatures confirms that these tertiary amines take part in the solvation of the starting aldehyde, thus contributing to a solvent effect on facial selectivity. In some cases, the differential entropy of activation is the predominant factor in differentiating the diastereoselectivity among these hexane/amine mixtures. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).
Asymmetric Synthesis of Optically Active Alcohols with Two Chiral Centres from a Racemic Aldehyde by the Selective Addition of Dialkylzinc Reagents Using Chiral Catalysts
Niwa, Seiji,Hatanaka, Toshihiro,Soai, Kenso
, p. 2025 - 2027 (2007/10/02)
Optically 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 enantio-selective addition of dialkylzinc reagents using (1S,2R)-(-)-N,N-dibutylnorephedrine (DBNE) and (S)-(+)-diphenyl(1-methyl-pyrrolidin-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 configuaration of 1 and that (S)-1 reacted faster with dialkylzinc than did (R)-1.
