Comparison of Oxidative Aromatic Coupling and the Scholl Reaction |
| |
Authors: | Marek Grzybowski Kamil Skonieczny Prof. Dr. Holger Butenschön Prof. Dr. Daniel T. Gryko |
| |
Affiliation: | 1. Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, Warsaw (Poland);2. Institut für Organische Chemie, Leibniz Universit?t, Hannover, Schneiderberg 1B, 30167 Hannover (Germany);3. Faculty of Chemistry, Warsaw University of Technology, 00‐664 Warsaw (Poland) |
| |
Abstract: | Does the dehydrogenative coupling of aromatic compounds mediated by AlCl3 at high temperatures and also by FeCl3, MoCl5, PIFA, or K3[Fe(CN)6] at room temperature proceed by the same mechanism in all cases? With the growing importance of the synthesis of aromatic compounds by double C? H activation to give various biaryl structures, this question becomes pressing. Since some of these reactions proceed only in the presence of non‐oxidizing Lewis acids and some only in the presence of certain oxidants, the authors venture the hypothesis that, depending on the electronic structure of the substrates and the nature of the “catalyst”, two different mechanisms can operate. One involves the intermediacy of a radical cation and the other the formation of a sigma complex between the acid and the substrate. The goal of this Review is to encourage further mechanistic studies hopefully leading to an in‐depth understanding of this phenomenon. |
| |
Keywords: | arene coupling biaryls Lewis acids oxidative coupling Scholl reaction |
|
|