A Mechanistic Study of the Oxidation of Substituted Benzyl Alcohols with Trichloroisocyanuric Acid

IF 2.5 3区化学 Q2 CHEMISTRY, ORGANIC

European Journal of Organic Chemistry Pub Date : 2024-10-17 DOI:10.1002/ejoc.202400834

Marcio C. S. de Mattos, Carlos Vinícius Pinto dos Santos

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Abstract

A systematic mechanistic study employing kobs kineticsmeasurements, linear free‐energy relationship, hydrogen kinetic isotope effect and rate law, as well as the Density Functional Theory (DFT) approach (M06‐2x/6‐311G(d,p)) for the oxidation of diverse substituted benzyl alcohols with trichloroisocyanuric acid (TCCA) / H2O in 50 % MeCN / CH2Cl2 at 25.0 °C is present. The kinetic results showed an autocatalytic behavior and a primary kinetic isotope effect (4.22). The linear free‐energy relationship (σ, ρ = ‐1.22) indicated a mechanism change for 4‐CF3, 3‐NO2 and 4‐NO2 substituted benzyl alcohols and a fractional rate law (3.25) for benzyl alcohol. The DFT results indicated Cl2, formed in situ from TCCA and the benzyl alcohol, as the actual oxidizing species. Furthermore, calculations support the kinetic results with high agreement through a transition state that performs a hydride abstraction by autocatalytic Cl2 in the induction zone. In the case of substrates bearing strong electron withdrawing groups, the mechanism changes to hydrogen abstraction from the corresponding benzyl hypochlorite as the main pathway.

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三氯异氰尿酸氧化取代苄醇的机理研究

本研究采用 kobs 动力学测量、线性自由能关系、氢动力学同位素效应和速率定律，以及密度泛函理论（DFT）方法（M06-2x/6-311G(d,p)），对 25.0 °C下三氯异氰尿酸（TCCA）/H2O 在 50 % MeCN / CH2Cl2 中氧化各种取代的苯甲醇的过程进行了系统的机理研究。动力学结果显示了自催化行为和主要的动力学同位素效应 (4.22)。线性自由能关系（σ, ρ =-1.22）表明，4-CF3、3-NO2 和 4-NO2 取代的苯甲醇发生了机理变化，苯甲醇则出现了分数速率定律（3.25）。DFT 结果表明，由 TCCA 和苄醇在原位形成的 Cl2 是实际的氧化物种。此外，计算还通过过渡态支持了动力学结果，该过渡态在诱导区通过自催化 Cl2 进行氢化物抽取，与动力学结果高度一致。如果底物含有强取电子基团，则机理会转变为从相应的次氯酸苄酯中抽取氢气作为主要途径。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

European Journal of Organic Chemistry 化学-有机化学

CiteScore

5.40

自引率

3.60%

发文量

752

审稿时长

1 months

期刊介绍： The European Journal of Organic Chemistry (2019 ISI Impact Factor 2.889) publishes Full Papers, Communications, and Minireviews from the entire spectrum of synthetic organic, bioorganic and physical-organic chemistry. It is published on behalf of Chemistry Europe, an association of 16 European chemical societies. The following journals have been merged to form two leading journals, the European Journal of Organic Chemistry and the European Journal of Inorganic Chemistry: Liebigs Annalen Bulletin des Sociétés Chimiques Belges Bulletin de la Société Chimique de France Gazzetta Chimica Italiana Recueil des Travaux Chimiques des Pays-Bas Anales de Química Chimika Chronika Revista Portuguesa de Química ACH—Models in Chemistry Polish Journal of Chemistry.