Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (09): 2043-2050.doi: 10.3866/PKU.WHXB20110921


AuClx (x=1, 3)-Catalyzed Benzannulation Mechanisms between 2-Propynyl-hypnone and Benzyne

ZHU Yuan-Qiang1, GUO Jian-Chun2, YE Zhong-Bin1   

  1. 1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, School of Chemistry and Chemical Engineering,Southwest Petroleum University, Chengdu 610500, P. R. China;
    2. School of Petroleum Engineering, Southwest PetroleumUniversity, Chengdu 610500, P. R. China
  • Received:2011-05-09 Revised:2011-07-07 Published:2011-08-26
  • Contact: YE Zhong-Bin
  • Supported by:

    The project was supported by the Scientific Research Fund of Sichuan Provincial Education Department, China (09ZB099).

Abstract: The AuClx (x=1, 3)-catalyzed benzannulation mechanisms between benzyne and 2-propynylhypnone were investigated using B3LYP, B3PW91, UB3LYP, and the second-order Møller-Plesset perturbation (MP2) methods with the LanL2DZ basis set for Au and the 6-31G*, 6-311++G** basis sets for C, H, O, Cl. For the AuCl or AuCl3 catalysts the reaction occurs through both the [4 + 2] and the [3 + 2] benzannulation pathways to yield the product. With AuCl, the reaction occurs mainly through the [4 + 2] reaction pathway because of this pathway's low activation free energy. With AuCl3, the reaction occurs by the [4+2] and the [3+2] reaction pathways. These two pathways are competitive because of their close activation free energies. An analysis of these results indicates that the gold oxidation states change the reaction mechanisms and greatly influence the reaction barriers. The calculated results indicate that the AuCl catalyst is more effective than AuCl3 because in the reaction catalyzed by AuCl the activation free energy of the rate determining step is 11.18 kJ·mol-1 lower than that of the reaction catalyzed by AuCl3. These results are in good agreement with the experimental observations.

Key words: Gold catalyst, Density functional theory, Reaction mechanism, [4+2] Benzannulation, [3+2] Benzannulation