CAJ | 학술논문

采用密度泛函理论方法在B3LYP/6-311G(d,p)水平上研究了锗苯与一些亲二烯体的Diels-Alder反应的微观机理和势能剖面, 考察了取代基和苯溶剂对反应势能剖面的影响, 探讨了杂Diels-Alder反应中区域选择性的起源. 计算结果表明, 所研究反应均以协同的方式进行. 亲二烯体分子碳原子上的苯基取代基对杂Diels-Alder反应中2个新键形成的非同步性和活化能垒的影响与最终产物中苯基和锗原子间的相对位置有关, 锗苯分子中锗原子上的CCl_3取代基在热力学和动力学上均有利于反应的进行. 苯溶剂对所研究反应的势能剖面影响较小. 实验观察到的杂Diels-Alder反应的区域选择性由动力学因素所控制.
채용밀도범함이론방법재B3LYP/6-311G(d,p)수평상연구료타분여일사친이희체적Diels-Alder반응적미관궤리화세능부면, 고찰료취대기화분용제대반응세능부면적영향, 탐토료잡Diels-Alder반응중구역선택성적기원. 계산결과표명, 소연구반응균이협동적방식진행. 친이희체분자탄원자상적분기취대기대잡Diels-Alder반응중2개신건형성적비동보성화활화능루적영향여최종산물중분기화타원자간적상대위치유관, 타분분자중타원자상적CCl_3취대기재열역학화동역학상균유리우반응적진행. 분용제대소연구반응적세능부면영향교소. 실험관찰도적잡Diels-Alder반응적구역선택성유동역학인소소공제.
Density functional theory(DFT) calculations, at the B3LYP/6-311G(d,p) level of theory, were performed to study the reaction mechanism and potential energy surface of the Diels-Alder reactions between germabenzenes and some dienophiles. The influences of substituents and benzene as a solvent on the potential energy surface of the hetero-Diels-Alder reactions were investigated and the origin of regioselectivity in the he-tero-Diels-Alder reactions was explored. Our calculation results show that all of studied reactions proceed in a concerted way. The influences of phenyl at C atom of dienophiles on the asynchronicity in the bond-formation process and activation barrier of reaction are closely related to the relative position of phenyl with respect to Ge atom in products. The CCl_3 group at Ge atom of germabenzene molecule is in favor of process of the hetero-Diels-Alder reactions and solvent effect is not crucial for the potential energy surfaces of the studied reactions. The present calculations reproduce the regioselectivity observed experimentally in hetero-Diels-Alder reactions, which indicates that the kinetic factor controls the reaction proceeding.