Substituted Diarylnorbornadienes and Quadricyclanes: Synthesis, Photochemical Properties, and Effect of Substituent on the Kinetic Stability of Quadricyclanes
| Autor: | Lyndsey M. Shaak, Benjamin R. Rupert, Aaron N. Jahn, Andrew R. Ehle, Jesse V. Walker, Karyn M. Usher, James M. Tocyloski, Maria J. Sanford, Kyle J. Spivack, Felix E. Goodson, Obiamaka Obianyo |
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| Rok vydání: | 2017 |
| Předmět: |
chemistry.chemical_classification
Alkene Norbornadiene Organic Chemistry Substituent Aromaticity 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences Coupling reaction 0104 chemical sciences chemistry.chemical_compound chemistry Dehydrogenation Quadricyclane 0210 nano-technology Methyl group |
| Zdroj: | The Journal of Organic Chemistry. 82:1301-1315 |
| ISSN: | 1520-6904 0022-3263 |
| Popis: | In this Article, we present a new method for the synthesis of diarylnorbornadiene derivatives. Through the use of a two-step procedure consisting of a tandem alkene insertion-Suzuki coupling reaction followed by a DDQ dehydrogenation, we have been able to synthesize derivatives with a wide variety of substituents. We also present the results of UV-visible spectroscopy studies and kinetics experiments that show the effect of substituent on light absorption properties of the norbornadienes as well as the kinetic stability of the quadricyclanes that result from their photochemical conversion. While substitution on the aromatic rings had comparatively little effect on quadricyclane lability, substitution at a bridgehead position with a methyl group produced a quadricyclane that thermally reverted to the norbornadiene at a rate that was significantly slower than that for the quadricyclane without the methyl substituent. From the results of the kinetics experiments, we determined that the reversion of the quadricyclanes occurs via a free radical mechanism with very little contribution from polar effects. This observation led us to speculate as to whether our data may form the basis for a free radical substituent constant, σ |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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