Chin. J. Org. Chem. ›› 2017, Vol. 37 ›› Issue (3): 608-616.DOI: 10.6023/cjoc201609020 Previous Articles     Next Articles



李强根a, 向仕凯a, 毛双a, 任译b   

  1. a 四川师范大学化学与材料科学学院 成都 610068;
    b 四川大学化学学院 成都 610068
  • 收稿日期:2016-09-18 修回日期:2016-12-07 发布日期:2016-12-21
  • 通讯作者: 李强根,;任译,;
  • 基金资助:


Theoretical Investigations on the Intramolecular N-Arylation Mechanism and Reactivity for the Synthesis of Benzimidazoles by Base-Catalyzed

Li Qianggena, Xiang Shikaia, Mao Shuanga, Ren Yib   

  1. a College of Chemistry and Materials Science, Sichuan Normal University, Chengdu 610068;
    b College of Chemistry, Sichuan University, Chengdu 610064
  • Received:2016-09-18 Revised:2016-12-07 Published:2016-12-21
  • Contact: 10.6023/cjoc201609020;
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 21202109), the Research Fund of Department of Education, of Sichuan Province (No. 13ZB0160) and the Research Funds of Sichuan Normal University (No. 16ZP10).

Quantum chemical studies on the intramolecular N-arylation mechanism and reactivity of N-(2-halogen phenyl)-N'-phenyl ethyl amidines in dimethyl sulfoxide (DMSO) for the synthesis of benzimidazoles by base-catalyzed have been performed at MP2/6-311+G**//B3LYP/6-311+G** level of theory. The results indicate that the mechanism of the title reactions is not the radical mechanism or stepwise SNAr pathway, but the concerted SNAr pathway with a transition state, which is compared with the conclusion of Bolm et al. The reactivity of the title reactions can not be interpreted by the geometric looseness or natural population analysis. Multi parameter fitting reveals that the reactivity of the title reactions is controlled mostly by the regional nucleophilicity index ωN10- of the nucleophile N10 atom or highest occupied molecular orbital energy EHOMO of the reactant, the other factor is the charges of the nucleophilic atom N10, while the charges of the C2 atom and the geometric looseness L% have almost no effect on the reaction energy barrier. The relative energies and the reactivity of the title reactions attained at MP2/6-311+G**//B3LYP/6-311+G** level of theory are better agreement with the experimental results compared with the other methods.

Key words: intramolecular N-arylation, N-(2-halogen phenyl)-N'-phenyl ethyl amidines, reaction mechanism, SNAr reaction, B3LYP, nucleophilicity index