Mechanistic Investigations into the Cation Radical Newman–Kwart Rearrangement
| Autor: | David A. Nicewicz, Cole L. Cruz |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Olefin fiber
010405 organic chemistry Thiophenol Reactive intermediate General Chemistry Newman–Kwart rearrangement 010402 general chemistry Photochemistry 01 natural sciences Catalysis 0104 chemical sciences chemistry.chemical_compound chemistry Nucleophile Intramolecular force Thermochemical cycle |
| Zdroj: | ACS Catalysis. 9:3926-3935 |
| ISSN: | 2155-5435 |
| DOI: | 10.1021/acscatal.9b00465 |
| Popis: | Efforts to elucidate the governing factors in the cation radical Newman–Kwart rearrangement are described. Through a combination of spectroscopic and kinetic analyses, it has been shown that the reactive intermediate is a thione cation radical that has significant thiyl radical character. This intermediate undergoes similar chemistry, such as olefin stereomutation, that has been observed for thiyl radicals generated by other means. Moreover, kinetic studies demonstrate that the electronic dependence observed in the system is the result of rate-limiting intramolecular nucleophilic trapping of the thione cation radical. Importantly, the thiyl radical character of the reactive intermediate can be used to rationalize all reaction observations. This mechanistic model is in line with observed rate enhancement at higher dilutions that decreases the formation of an off-cycle intermediate. A thermochemical cycle was devised to predict which substrates will most easily undergo the cation-radical-mediated rearrangement. |
| Databáze: | OpenAIRE |
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