高等学校化学研究（英文版）
高等學校化學研究（英文版）
고등학교화학연구（영문판）
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
2011年
4期
673-677
,共5页
Syn- and anti-Mannich reaction%Stereoselectivity%Amino acid%Transition state
The effects of two different amino acid catalysts on the stereoselectivities in the direct Mannich reactions of cyclohexanone,p-anisidine and p-nitrobenzaldehyde were studied with the aid of density functional theory.Transition states of the stereo-determining C—C bond-forming step with the addition of enamine intermediate to the imine for the L-proline(α-amino acid) and (R)-3-pyrrolidinecarboxylic acid(β-amino acid)-catalyzed processes were reported.B3LYP/6-31G** calculations provide a good explanation for the opposite syn vs.anti diastereoselectivities of these two different kinds of catalysts(syn-selectivity for the α-amino acid catalysts,anti-selectivity for the β-amino acid catalysts).Calculated and observed diastereomeric ratio and enantiomeric excess values are in reasonable agreement.
