硅杂苯与甲醛和二苯甲酮的ielDs-Alder反应的理论研究

Theoretical Studies on the Diels-Alder Reactions of Silabenzenes with Formaldehyde and Benzophenone

摘要: 采用密度泛函理论(DFT)方法在B3LYP/6-311G(d,p)水平上研究了硅杂苯与甲醛和二苯甲酮的Diels-Alder反应的微观机理、势能剖面和取代基效应.计算结果表明,所研究反应均为协同的基元反应,形成1个Si-O键的反应中2个新键的形成具有较大的非同步性,而其他反应的非同步性相对较小.羰基碳原子上的苯基取代基不利于反应的进行,而硅杂苯分子中硅原子上的C(CH3)3与CCl3取代基有利于反应的进行.硅原子参与的反应在热力学和动力学上均远比不涉及硅原子的反应容易进行,而形成1个Si-O键的反应比形成1个Si-C键的反应容易进行,此结果与实验一致.

Abstract: The mechanism,potential energy surface and substituent effect of Diels-Alder reactions of silabenzenes with formaldehyde and benzophenone have been investigated using density functional theory(DFT) at the B3LYP/6-311G(d,p) level of theory.It was found that all of studied reactions are concerted elementary reaction and the reaction forming one Si-O bond has much larger asynchronicity in the bond-formation process than other reactions.Phenyl group at C atom of carbonyl disfavors the Diels-Alder reaction,while...