2-锗萘与甲醛、二苯甲酮的杂环加成反应的研究

Studies on the hetero-cycloaddition reactions of 2-germanaphthlenes with formaldehyde and benzophenone

2-锗萘由于其芳香性和高反应性,而引起化学家们的浓厚兴趣。本文采用密度泛函理论(DFT)在B3LYP/6-311G(d,p)水平,研究2-锗萘与甲醛、二苯甲酮的[2+2]和[4+2]杂环加成反应的微观机理、势能剖面,考察取代基和四氢呋喃溶剂对反应势能剖面的影响。计算结果表明,所研究的反应均为协同但非同步的方式,且Ge-O键总是先于C-C键形成。羰基碳原子上的苯取代基不利于反应,而2-锗萘分子中锗原子上的C(CH_3)_3与CCl_3取代基却有利于反应。四氢呋喃溶剂对加成反应的势能剖面影响不大。[2+2]比[4+2]反应容易,与实验一致。

2-Germanaphthlene, for its aromaticity and high reactivity, has attracted much attention from chemists. In this paper, density functional theory （DFT） calculations at the B3LYP/6-311 G（ d, p） level were employed to investigate the mechanism and potential energy surface of [ 2 ＋ 2 ] and [ 4 ＋ 2 ] hetero-cycloaddition reactions of 2-germanaphthlenes with formaldehyde and benzophenone. The influences of substituents and tetrahydrofuran （THF） as a solvent on the potential energy surface of reactions were explored. The results show that all of studied reactions proceed via a concerted but asynchronous way and that the Ge-O bond formation foregoes the C- C. Phenyl groups at C atom of carbonyl disfavor the hetero-cycloaddition reactions, while C （ CH3 ） 3 and CCl3 groups have opposite effects. The influence of tetrahydrofuran （THF） solvent on the potential energy surface of the studied reactions is not large. The [2 ＋ 2 ] reactions proceed more easily than those corresponding [ 4 ＋ 2 ] reactions, which is in full agreement with experimental observation.