Stereoselectivities in α- and β-Amino Acids Catalyzed Mannich Reactions Involving Cyclohexanone  

作　　者：WANG Ying FU Ai-ping LI Hong-liang TIAN Feng-hui YUAN Shu-ping SI Hong-zong DUAN Yun-bo WANG Zong-hua 

机构地区：[1]Institute for Computational Science and Engineering, Laboratory of New Fiber Materials and Modern Textile, Growing Base for State Key Laboratory, College of Chemical and Environmental Engineering, Qingdao University, Qingdao 266071, P. R. China

出　　处：《Chemical Research in Chinese Universities》2011年第4期673-677,共5页高等学校化学研究（英文版）

基　　金：Supported by the National Natural Science Foundation of China(Nos.20773071,20901043);the Natural Science Foundation of Shandong Province,China(No.ZR2010BM024);the Project of Shandong Province Higher Educational Science and Technology Program,China(No.J10LB06)

摘　　要：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（·-amino acid） and （R）-3-pyrrolidinecarboxylic acid（·-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 ·-amino acid catalysts,anti-selectivity for the ·-amino acid catalysts）.Calculated and observed diastereomeric ratio and enantiomeric excess values are in reasonable agreement.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（·-amino acid） and （R）-3-pyrrolidinecarboxylic acid（·-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 ·-amino acid catalysts,anti-selectivity for the ·-amino acid catalysts）.Calculated and observed diastereomeric ratio and enantiomeric excess values are in reasonable agreement.

关 键 词：Syn-and anti-Mannich reaction STEREOSELECTIVITY Amino acid Transition state 

分 类 号：TQ94[化学工程] TQ281