Аннотация
The kinetics and mechanism of concurrent bromo-de-protonation and bromo-de-tert-butylation of 1,3,5-tri-tert-butylbenzene at different bromine concentrations were studied experimentally and theoretically. Both reactions have high order in bromine (experimental kinetic orders ∼5 and ∼7, respectively). According to quantum chemical DFT calculations, such high reaction orders are caused by participation of clustered polybromide anions Br 2n−1 - in transition states. Bromo-de-tert-butylation has a higher order due to its bigger reaction center demanding clusters of extended size. A significant primary deuterium kinetic isotope effect (KIE) for bromo-de-protonation is measured indicating proton removal is rate limiting, as confirmed by computed DFT models. The latter predict a larger value for the KIE than measured and possible explanations for this are discussed.
Язык оригинала | английский |
---|---|
Страницы (с-по) | 3781-3789 |
Число страниц | 9 |
Журнал | Organic and Biomolecular Chemistry |
Том | 17 |
Номер выпуска | 15 |
DOI | |
Состояние | Опубликовано - 21 апр 2019 |