Research data supporting "Computational in-sights on the origin of enantioselectivity in reactions with diarylprolinol silyl ether catalysts via a radical pathway"

In this project, the stereoselective reaction of 1,4-dicarbonyls with diarylprolinol silyl ether catalysts was studied with force field and density functional theory calculations. A robust procedure has been developed for computational investigations of large and flexible chemical systems based on the conformation labelling system, ONIOM calculations and Python scripting. The change in enantiomeric excess due to variations in the catalyst can be explained based on conformational changes and structural deformations. In the enantioselectivity-determining radical addition step, the iminium in the most stable SR transition state (TS) takes up the conformation of the most stable ground state iminium (EE). The conjugated iminium in the SS TS adopts an EZ conformation to avoid potential structural deformations due to radical attacks from the more sterically hindered position. For systems with simpler catalysts, the iminium is EE for both, as the steric hindrance imposed by the substituent is not sufficient to cause this large structural deformation, and so the reaction shows poor enantioselectivity.

The key DFT structures are included in the ‘SI_key_structure’ folder as Gaussian calculation output files.

在本项目中，研究人员采用力场和密度泛函理论计算对1,4-二羰基化合物与芳基丙氨酸基硅醚催化剂的立体选择性反应进行了研究。基于构象标记系统、ONIOM计算和Python脚本，本研究开发了一套稳健的计算方法，用于对大而灵活的化学系统进行计算探究。催化剂变化引起的对映异构体过量变化可以通过构象变化和结构畸变来解释。在决定对映选择性的自由基加成步骤中，最稳定的SR过渡态（TS）中的亚胺采取了最稳定基态亚胺（EE）的构象。SS TS中的共轭亚胺采取EZ构象，以避免由于来自更为空间阻碍位置自由基攻击而可能引起的结构畸变。对于具有更简单催化剂的系统，亚胺在两种情况下均为EE，因为取代基带来的空间阻碍不足以引起这种大的结构畸变，因此反应表现出较差的对映选择性。关键DFT结构已包含在‘SI_key_structure’文件夹中，作为高斯计算输出文件。