Theoretical insight into phosphoric acid-catalyzed asymmetric conjugate addition of indolizines to a,β-unsaturated ketones  

作　　者：Haohua Chen Lei Zhu Kangbao Zhong Xiaoyu Yue Ling-Bo Qu Ruopeng Bai Yu Lan 

机构地区：[1]School of Chemistry and Chemical Engineering, Chongqing University [2]College of Chemistry and Molecular Engineering, Zhengzhou University

出　　处：《Chinese Chemical Letters》2018年第8期1237-1241,共5页中国化学快报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 21772020);the Fundamental Research Funds for the Central Universities (Chongqing University) (No. 106112017CDJXY220007)

摘　　要：Phosphoric acid catalysis is a powerful tool for the construction of new CààC bonds because of its unique LUMO-lowering activity. Theoretical calculations were employed to investigate phosphoric acidcatalyzed asymmetric conjugate addition of indolizines to a,b-unsaturated ketones. The calculation results showed that this transformation proceeds via a reaction pathway involving nucleophilic addition,deprotonation–aromatization, and tautomerization. The computational results showed that deprotonation–aromatization is the rate-determining step and the enantioselectivity-determining step.The S-configured product was preferentially generated via a pathway starting from the s-cis conjugated ketone, whereas the s-trans isomer led to a side product with the R configuration. Non-covalent interaction analysis showed that the enantioselectivity is mainly caused by bond-rotation strain in the transition states of the deprotonation–aromatization step.Phosphoric acid catalysis is a powerful tool for the construction of new CààC bonds because of its unique LUMO-lowering activity. Theoretical calculations were employed to investigate phosphoric acidcatalyzed asymmetric conjugate addition of indolizines to a,b-unsaturated ketones. The calculation results showed that this transformation proceeds via a reaction pathway involving nucleophilic addition,deprotonation–aromatization, and tautomerization. The computational results showed that deprotonation–aromatization is the rate-determining step and the enantioselectivity-determining step.The S-configured product was preferentially generated via a pathway starting from the s-cis conjugated ketone, whereas the s-trans isomer led to a side product with the R configuration. Non-covalent interaction analysis showed that the enantioselectivity is mainly caused by bond-rotation strain in the transition states of the deprotonation–aromatization step.

关 键 词：Phosphoric acid catalysis Theoretical calculations MECHANISM ENANTIOSELECTIVITY 

分 类 号：O621.251[理学—有机化学]