University Chemistry ›› 2021, Vol. 36 ›› Issue (6): 2008009.doi: 10.3866/PKU.DXHX202008009

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Further Discussion on the Mechanism of Hydroboration of Olefins

Lei Zhang1,*(), Jianguo Zhou1, Yongzhu Zhou1,2   

  1. 1 School of Science, Tianjin Chengjian University, Tianjin 300384, China
    2 School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
  • Received:2020-08-04 Accepted:2020-09-03 Published:2020-09-24
  • Contact: Lei Zhang E-mail:zhanglei-chem@tcu.edu.cn

Abstract:

Hydroboration of olefins is a concerted addition reaction involving only one step. It is generally considered to proceed via a four-center cyclic transition state. We performed theoretical studies on the reaction mechanism of the hydroboration of propene using quantum chemistry calculations, which led to a unique transition state that was inconsistent with the so-called four-center cyclic structure. In the computed transition state, the boron atom is bonded to both of the olefinic carbon atoms, and the degree of the hydrogen shift event is very low. All of these observations are consistent with those reported in the literature. Further theoretical studies revealed that the reaction might involve certain structures similar to the four-center cyclic structure, appearing as the transient states between the transition state and the product. Finally, the reaction mechanism of hydroboration was analyzed from the perspective of the orbital interaction model.

Key words: Hydroboration, Reaction mechanism, Transition state, Orbital interaction, Olefin

MSC2000: 

  • G64