Juárez-Ornelas Kevin A, Solís-Hernández Manuel, Navarro-Santos Pedro, Jiménez-Halla J Oscar C, Solorio-Alvarado César R
Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Campus Gto, Noria Alta S/N 36050, Guanajuato, México.
CONAHCYT - Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Avenida Francisco J. Múgica S/N 58030, Morelia, Michoacán, México.
Beilstein J Org Chem. 2024 Jul 15;20:1580-1589. doi: 10.3762/bjoc.20.141. eCollection 2024.
The reaction mechanism for the chlorination and bromination of 2-naphthol with PIDA or PIFA and AlX (X = Cl, Br), previously reported by our group, was elucidated via quantum chemical calculations using density functional theory. The chlorination mechanism using PIFA and AlCl demonstrated a better experimental and theoretical yield compared to using PIDA. Additionally, the lowest-energy chlorinating species was characterized by an equilibrium of Cl-I(Ph)-OTFA-AlCl and [Cl-I(Ph)][OTFA-AlCl], rather than PhICl being the active species. On the other hand, bromination using PIDA and AlBr was more efficient, wherein the intermediate Br-I(Ph)-OAc-AlBr was formed as active brominating species. Similarly, PhIBr was higher in energy than our proposed species. The reaction mechanisms are described in detail in this work and were found to be in excellent agreement with the experimental yield. These initial results confirmed that our proposed mechanism was energetically favored and therefore more plausible compared to halogenation via PhIX.
我们小组之前报道过，使用密度泛函理论通过量子化学计算阐明了2-萘酚与PIDA或PIFA以及AlX（X = Cl，Br）进行氯化和溴化的反应机理。与使用PIDA相比，使用PIFA和AlCl的氯化机理显示出更好的实验和理论产率。此外，能量最低的氯化物种的特征是Cl-I(Ph)-OTFA-AlCl和[Cl-I(Ph)][OTFA-AlCl]处于平衡状态，而不是PhICl作为活性物种。另一方面，使用PIDA和AlBr进行溴化更有效，其中中间体Br-I(Ph)-OAc-AlBr作为活性溴化物种形成。同样，PhIBr的能量高于我们提出的物种。本文详细描述了反应机理，发现其与实验产率非常吻合。这些初步结果证实，与通过PhIX进行卤化相比，我们提出的机理在能量上更有利，因此更合理。
