Department of Chemistry, Faculty of Science, Atatürk University, Erzurum 25240, Turkey.
Department of Chemistry, Hacettepe University, Ankara 06800, Turkey.
Org Biomol Chem. 2021 Nov 10;19(43):9483-9490. doi: 10.1039/d1ob01607e.
A computational study of 2,2-azobis(isobutyronitrile) (AIBN)-initiated aerobic oxidative cleavage of alkenes is carried out employing density functional theory (DFT) and high-level coupled-cluster methods, such as coupled-cluster singles and doubles with perturbative triples [CCSD(T)]. Our computations show that the barriers for the formation of dioxetane derivatives suggested by Xu and co-workers (, 2014, , 7220-7225) for the reaction mechanism of aerobic oxidative cleavage of alkenes are computed to be higher than 65 kcal mol. This barrier is relatively high under the reaction conditions. Our results for the Xu mechanism indicate that the reaction does not proceed the formation of a dioxetane ring under the reaction conditions. Our results demonstrate that the reaction of aerobic oxidative cleavage of geminal alkenes in the presence of AIBN is initiated by the peroxyl radical 9, contrary to the isobutyronitrile radical 2. Our results show that the 2-(2-hydroxyl-1,1-diarylethoxy)-2-methylpropanenitrile radical (15) does not appear throughout the reaction scheme and the reaction progresses over the 2-(2-hydroxyl-2,2-diarylethoxy)-2-methylpropanenitrile radical (13) rather than the 2-(2-hydroxyl-1,1-diarylethoxy)-2-methylpropanenitrile radical (15). Our results are in agreement with the experimental results for the aerobic oxidative cleavage of the geminal disubstituted alkenes. Our results also demonstrate that the epoxide derivatives can be formed as an intermediate under the reaction conditions. This reaction is not applicable for pyridine derivatives due to the conversion of vinylpyridine derivatives to -oxide derivatives.
采用密度泛函理论（DFT）和高阶耦合簇方法，如耦合簇单双加缀三[CCSD(T)]，对 2,2-偶氮双（异丁腈）（AIBN）引发的烯烃有氧氧化断裂的计算研究。我们的计算表明，Xu 及其同事提出的用于烯烃有氧氧化断裂反应机理的二氧杂环丁烷衍生物的形成势垒（，2014，，7220-7225）计算值高于 65 kcal/mol。在反应条件下，这个势垒相对较高。我们对 Xu 机制的研究结果表明，在反应条件下，反应不会进行二氧杂环丁烷环的形成。我们的结果表明，在 AIBN 的存在下，偕二烯烃的有氧氧化断裂反应是由过氧自由基 9 引发的，而不是异丁腈自由基 2。我们的结果表明，2-（2-羟基-1,1-二芳基乙氧基）-2-甲基丙腈自由基（15）在整个反应方案中都不会出现，反应是在 2-（2-羟基-2,2-二芳基乙氧基）-2-甲基丙腈自由基（13）上进行的，而不是在 2-（2-羟基-1,1-二芳基乙氧基）-2-甲基丙腈自由基（15）上进行的。我们的结果与偕二取代烯烃有氧氧化断裂的实验结果一致。我们的结果还表明，在反应条件下可以形成环氧化物衍生物作为中间体。由于乙烯基吡啶衍生物转化为 -氧化物衍生物，该反应不适用于吡啶衍生物。
