Understanding how charge-charge interaction affects the stereochemistry of enamine fluorination by chiral primary amine catalysis  

作　　者：Yanfang Han Kai Yang Long Zhang Sanzhong Luo Jin-Pei Cheng 

机构地区：[1]Center of Basic Molecular Science(CBMS),Department of Chemistry,Tsinghua University,Beijing 100084,China [2]Haihe Laboratory of Sustainable Chemical Transformations,Tianjin 300192,China

出　　处：《Science China Chemistry》2023年第10期2828-2835,共8页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China (22373056, 22031006);the Haihe Laboratory of Sustainable Chemical Transformations (YYJC202113);the National Science & Technology Fundamental Resource Investigation Program of China (2018FY201200);supported by the National Program of Top-notch Young Professionals。

摘　　要：Electrostatic interaction, especially electrostatic attraction, usually plays critical roles in controlling the reactivity and selectivity in catalytic transformations;however, the like-charge repulsion, which is ubiquitous in physical systems, is rarely applied in reaction control. Herein we disclosed an unexpected like-charge repulsion induced enantio-control mode in primary aminecatalyzed fluorination reactions with 1-fluoro-2,4,6-trimethylpyridinium triflate. The ionic reaction works favorably in both highly polar(methanol) and non-polar(hexane) solvents, a seldom observed phenomenon in asymmetric catalysis. Erying plot analysis showed that an inversion temperature existed in Me OH, which was explained by the solvent-solute cluster model under different temperatures. Density functional theory(DFT) study and energy decomposition analysis(EDA) verified that the likecharge repulsion takes effect in polar solvent methanol, while in nonpolar solvents, the steric repulsion associated with ion-pair was found to be the major effect for the observed enantioselectivity.

关 键 词：AMINOCATALYSIS FLUORINATION like-charge repulsion iso-inversion temperature ion-pair effect 

分 类 号：O621.251[理学—有机化学]