Computational Insight into the Mechanism of Mannich Reaction between Glycinate and Aryl N ‐Diphenylphosphinyl Imine Catalyzed by N‐Quaternized Pyridoxal
Computational Insight into the Mechanism of Mannich Reaction between Glycinate and Aryl N ‐Diphenylphosphinyl Imine Catalyzed by N‐Quaternized Pyridoxal
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DOI：
10.1002/slct.202001606
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发表时间：
2020-06
期刊：
影响因子：
2.1
通讯作者：
Yongsheng Yang;Yan Zhang;Junxia Yang;Ying Xue
中科院分区：
文献类型：
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作者：
Yongsheng Yang;Yan Zhang;Junxia Yang;Ying Xue
Recently, Chen et al. reported an asymmetric biomimetic Mannich reaction oftert‐butyl glycinate (sub‐1) with arylN‐diphenylphosphinyl imine (sub‐2) catalyzed byN‐quaternized pyridoxal analogue (cat) (Chenetal.,Science,2018,360, 1438–1442). By utilizing Gaussian 09 program, we provide the detailed density functional theory (DFT, including B3LYP−D3 and M06‐2X) investigations on the mechanisms of each section of the reaction with CHCl3as implicit solvent. Thesecat,sub‐1and OH−if it exists can act as catalytic base and need to overcome relative free energy barrier of ∼12, 13.5 and 4.2 kcal/mol, respectively, to achieve α‐carbon deprotonation. During the addition reaction, the most favorable transition structure was calculated to overcome a relative free energy barrier of 6.3 kcal/mol, verifying the bifunctional activation mode ofcat. The final hydrolysis reaction starts with hydration to achieve protonation at the N atom ofsub‐2portion and generates a carbinolamine. These computational results help one obtain deep understanding of the reaction mechanism and benefit future design of pyridoxal catalyst and similar biomimetic reaction.
