Kinetics of α-(2,6-Dimethylphenl)vinyllithium: How To Control Errors Caused by Inefficient Mixing with Pairs of Rapidly Competing Ketones
| Autor: | Petra Böhrer, Claudia Behringer, Rudolf Knorr, Jakob Ruhdorfer, Monika Knittl |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
chemistry.chemical_classification
Order of reaction Ketone 010405 organic chemistry Dimer Organic Chemistry 010402 general chemistry Photochemistry 01 natural sciences Medicinal chemistry 0104 chemical sciences Cyclopropane chemistry.chemical_compound Reaction rate constant chemistry Reagent Electrophile Acetone |
| Zdroj: | The Journal of Organic Chemistry. 82:2843-2854 |
| ISSN: | 1520-6904 0022-3263 |
| DOI: | 10.1021/acs.joc.6b02686 |
| Popis: | Kinetic studies are a suitable tool to disclose the role of tiny reagent fractions. The title compound 2 reacted in a kinetic reaction order of 0.5 (square root of its concentration) with an excess of the electrophiles ClSiMe3, 1-bromobutane (n-BuBr), or 1-iodobutane (n-BuI) at 32 °C in Et2O or in hydrocarbon solvents. This revealed that the tiny (NMR-invisible) amount of a deaggregated equilibrium component (presumably monomeric 2) was the reactive species, whereas the disolvated dimer 2 was only indirectly involved as a supply depot. Selectivity data (relative rate constants κobs) were collected from competition experiments with the faster reactions of 2 in THF and the addition reactions of 2 to carbonyl compounds. This provided the rate sequences of Et2C═O > dicyclopropyl ketone > t-Bu-C(═O)-Ph > diisopropyl ketone ≫ t-Bu2C═O > ClSiMe3 > n-BuI > n-BuBr ≈ (bromomethyl)cyclopropane (but t-Bu2C═O acetone ≥ t-Bu–CH═O. It is suggested that a dece... |
| Databáze: | OpenAIRE |
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