Institute for Computational Science and Engineering, Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071, China.
J Phys Chem A. 2013 Apr 4;117(13):2862-72. doi: 10.1021/jp3126363. Epub 2013 Mar 21.
The chemo-, diastereo-, and enantioselectivities in proline and axially chiral amino sulfonamide-catalyzed direct aldol reactions between two enolizable aldehydes with different electronic nature have been studied with the aid of density functional theory (DFT) method. The potential energy profiles for the enamine formation between each aliphatic aldehyde and the catalyst confirm that two subject catalysts can successfully differentiate between 3-methylbutanal as an enamine component and α-chloroaldehydes as a carbonyl component. Transition states associated with the stereochemistry-determining C-C bond-forming step with the enamine intermediate addition to the aldehyde acceptor for proline and chiral amino sulfonamide-promoted aldol reactions are reported. DFT calculations not only provide a good explanation for the formation of the sole cross-aldol product between two aliphatic aldehydes both bearing α-methylene protons but also well reproduce the opposite syn vs anti diastereoselectivities in the chiral amino sulfonamide and proline-catalyzed aldol reactions.
在密度泛函理论（DFT）方法的辅助下，研究了脯氨酸和轴向手性氨基磺酰胺催化的两种不同电子性质的烯醇醛之间的直接Aldol 反应中的化学选择性、非对映选择性和对映选择性。每个脂肪醛与催化剂之间形成烯胺的势能曲线证实，两个主题催化剂可以成功地区分 3-甲基丁醛作为烯胺组分和α-氯醛作为羰基组分。报道了脯氨酸和手性氨基磺酰胺促进的Aldol 反应中，与烯胺中间体加成到醛受体的立体化学决定的 C-C 键形成步骤相关的过渡态。DFT 计算不仅很好地解释了两个都带有α-亚甲基质子的脂肪醛之间的唯一交叉Aldol 产物的形成，而且很好地再现了手性氨基磺酰胺和脯氨酸催化的Aldol 反应中相反的 syn 对反非对映选择性。
