Säurekatalysierte Dienon-Phenol-Umlagerungen von 6-Propargyl-6-methyl-cyclohexa-2,4-dien-1-onen; ladungskontrollierte, aromatische [1s, 2s]- und [3s, 4s]-sigmatropische Reaktionen
✍ Scribed by Ulrich Widmer; Hans-Jürgen Hansen; Hans Schmid
- Publisher
- John Wiley and Sons
- Year
- 1973
- Tongue
- German
- Weight
- 851 KB
- Volume
- 56
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
The acid catalysed dienone‐phenol rearrangement of methyl substituted o‐propargyl‐cyclohexadienones (scheme 3) was investigated. The rearrangements were carried out in acetic anhydride containing about 1^0^/~00~ sulfuric acid. Under these conditions acetoxy benzenium ions are formed as intermediates. These then undergo charge‐controlled [3__s__, 4__s__]‐ and [1__s__, 2s]‐sigmatropic rearrangements. Thus, the [3__s__, 4s]‐process leads to the formation of the corresponding allenyl‐phenol acetates (19, 21, 23, 25, 28, 30) whereas the [1__s__, 2s]‐process yields propargyl‐phenol acetates (20, 22, 24, 26, 29), respectively (cf. scheme 4).
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