2-三甲基硅乙炔基-6-甲基苯酚的反应机理研究

Study on the Reaction Mechanism for GaCl_3-Catalyzed 2-(trimethylsilylethynyl)-6-methyl-phenol

用密度泛函B3LYP/6-31G*方法研究了在GaC l3催化下邻甲酚邻炔基化产生2-三甲基硅乙炔基-6-甲基苯酚的反应机理.计算研究得到两条反应途径相关的反应物、中间体、复合物、过渡态和产物的几何优化构型及其能量,并进行振动频率计算以确证其几何构型的正确性.结果表明:途径1比途径2易进行;在途径1中,反应分多步进行,决速步骤是形成HC l离去的过程,能垒为99.87 kJ/mol.对途径1中的相关构型进行键级和自然电荷分析,并在B3LYP/6-311++G**水平下计算了单点能量.

The mechanism of GaCl3-catalyzed ortho-ethynylation of o-cresol leading to 2-（trimethylsilylethynyl）-6-methyl-phenol has been theoretically studied at the B3LYP/6-31G^＊ level. In this study, two reaction pathways have been investigated. The relevant geometries of all the reactants, intermediates, complexes, transition states and products have been located and verified with the vibrational frequency analysis. The calculations show that the pathway 1 is more favorable than the pathway 2 for the title reaction. For the pathway 1, the reaction is a stepwise process and the departure of HCl is the rate-controlled step. The corresponding barrier height is 99.87 kJ/mol in the rate-controlled step. The single-point calculations were also carried out at B3LYP/6-311 ^＋＋ G^＊ ＊//B3LYP/6- 31G ^＊ level. The relative configurations, bond indices and natural charges were also calculated and analyzed in this paper.