| Autor: |
Brenninger, Christoph, Jolliffe, John D., Bach, Thorsten |
| Předmět: |
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| Zdroj: |
Angewandte Chemie International Edition; 10/26/2018, Vol. 57 Issue 44, p14338-14349, 12p |
| Abstrakt: |
The first law of photochemistry, as described by Theodor von Grotthuß and John W. Draper, states that only the light absorbed by the irradiated matter can effect photochemical change. Consequently, the photochemical behavior of a molecule can be controlled by bringing its absorbance properties in line with the emission of the light source. A compound with a chromophore that only absorbs light at short wavelengths will not be excited by light of longer wavelengths. If one can reversibly modify the photophysical properties of a compound with a chemical activator, then it is possible to photoexcite only the activated species. For α,β‐unsaturated carbonyl compounds, the use of Lewis acids, Brønsted acids, or the formation of the respective iminium ions can bring about the desired chromophore activation to catalyze a photochemical reaction at a given wavelength. In this Minireview, the concept of chromophore activation will be illustrated, and examples of its implementation in enantioselective catalysis will be discussed. Walking the tightrope above the ground state: The absolute stereochemical outcome of a photochemical reaction can be controlled by activating the starting material with Lewis acids or Brønsted acids or through the formation of iminium ions. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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