Fukui函数和局域软度应用于亲电加成反应的区位选择性的研究（英文）

Fukui Function and Local Softness Related to the Regioselectivity of Electrophilic Addition Reactions

Fukui函数、局域软度、广义Fukui函数以及广义软度通常被称为反应描述符。使用它们研究和探讨了HCl与不对称烯烃以及溴苯硒与不对称苯乙烯的亲电加成反应的区位选择性。在MP2/6-311++G(d,p)理论水平下,采用有限差分方法计算这些反应描述符,同时也使用ABEEMσπ方法进行了计算。ABEEMσπ模型下的局域软度和广义局域软度,分别结合局域硬-软酸碱(HSAB)原理,得出亲电试剂氯化氢与溴苯硒,更容易进攻不对称乙烯和苯乙烯中的马氏碳原子,符合马氏规则。而有限差分方法不能完全地解释该系列反应的区位选择性。此外,主要产物所对应的马氏碳原子的广义局域软度值,就能够预测出此类反应的活性序列,所得结果与速率常数有很好的关联。

Regioselectivities of electrophilic addition reactions of hydrogen chloride to asymmetric alkenes and benzeneselenenyl bromide to substituted styrenes have been investigated by using reactivity descriptors, including Fukui function f（r）, local softness s（r）, generalized Fukui function fG（r）, and generalized local softness SG（r）. All of them are obtained from the finite difference approximation method calculated by ab initio method at MP2/6-311＋＋G（d,p） level of theory and our ABEEMarr model, respectively. According to the generalized version of the local hard-soft and acid-base （HSAB） principle, the forecasted regioselectivities of our investigated additions using the ABEEMσπ model are in fair agreement with the experimental values. In particular, we can also rationalize their reaction rate constants by the generalized local softness, i.e., the softest the site is, the easiest the reaction is. Hence, the generalized reactivity descriptors work quite well.