ORGN 824 |
| The oxidative phenol coupling reaction of simple phenols exhibiting simple methyl substituents can be difficult since several by-products occur. Such a challenging substrate is 2,4-dimethylphenol. We studied the electrochemical access to the ortho-coupled dehydrodimer. Anodic treatment in an basic electrolyte supports the formation of a molecular architecture called Pummerer`s ketone (1) and a variety of pentacyclic structures (2-4). Noteworthy, 2 is formed as an exclusive diastereomer. The selective ortho-coupling reaction was achieved by two ways which will be outline in detail: On the one hand a borate template 5 can be used. The tetraphenoxy borates can be easily made in large scale. Due to the ionic nature of 5 no supporting electrolyte is required. This methodology can be applied to several related phenolic substrates. On the other hand 2,4-dimethyl phenol can directly be converted on boron doped diamond anodes. Surprisingly, the electrochemical transformation does not destruct or mineralize the substrate.
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Combinatorial, Parallel and Process Chemistry, Heterocycles, Aromatics, New Reactions and Methodology
8:00 PM-10:00 PM, Wednesday, August 22, 2007 BCEC -- Exhibit Hall - B2, Poster
Sci-Mix
Division of Organic Chemistry |
