自然轨道福井函数和成键活性描述符应用于解释苯硫醌和1,3-二烯的[2+4]和[4+2]环加成反应中的成键机理（英文）

Application of Natural Orbital Fukui Functions and Bonding Reactivity Descriptor in Understanding Bond Formation Mechanisms Underlying [2+4] and [4+2] Cycloadditions of o-Thioquinones with 1,3-Dienes

苯硫醌与脂肪族烯烃可以发生[2+4]和[4+2]环加成反应。为了解释这些环加成反应中的成键过程,本文使用了自然轨道福井函数(NOFF)与成键活性描述符。自然轨道福井函数揭示了苯硫醌和脂肪族烯烃的键或轨道的亲电性,表明电子供体的成键轨道和电子受体的反键/成键轨道之间发生了电子转移,然后成环,在这一过程中有两个共价键形成,得到了环状产物。成键活性描述符表明共价键比较容易在一个分子中具有较大f^+_(k1)值的k1原子与另一个分子中具有较大f_(k2)值的k2原子之间形成。自然轨道福井函数与成键活性描述符都可以有效解释苯硫醌与1,3-二烯之间的[2+4]与[4+2]环加成反应的机理。

o-Thioquinones can undergo either [2 ＋ 4] or [4 ＋ 2] the bonding processes in these cycloadditions, the natural orbital cycloaddition reactions with acyclic dienes. To illustrate Fukui function （NOFF） and bonding reactivity descriptor have been employed. The electrophilicity of a bond or an orbital in the o-thioquinone as well as in the acyclic diene has been found using the NOFF, which suggests that electron transfer takes place from an electron-donating bonding orbital to an electron-accepting antibonding/bonding orbital, leading to the cyclic product via the formation of a circular loop and two covalent bonds. The bonding reactivity descriptor shows that covalent bonds readily form between atom kl of one molecule with a large fk1^- value and atom k2 of another molecule with a large f-2 value. Both the NOFF and the bonding reactivity descriptor are efficient tools for interpreting the mechanism underlying the [2 ＋ 4] and [4 ＋ 2] cycloaddition between o-thioquinones and acyclic dienes.