Intramolekulare Diels-Alder-Additionen in 6-Methyl-6-(penta-2,4-dienyl)-cyclohexa-2,4-dien-1-on-Systemen. Vorläufige Mitteilung
✍ Scribed by H. Greuter; Gy. Fráter; H. Schmid
- Publisher
- John Wiley and Sons
- Year
- 1972
- Tongue
- German
- Weight
- 365 KB
- Volume
- 55
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
Thermal rearrangement of trans‐penta‐2,4‐dienyl mesityl ether (trans‐1) gave, besides trans, cis‐2 and trans, trans‐2, the homotwistanone derivative 1,3,10‐trimethyl‐tricyclo[5.4.0.0^3,9^]undeca‐5,10‐dien‐2‐one (3) as well as its isomer 1,3,9‐trimethyl‐tricyclo[5.3.1.0^3,8^]undeca‐5, 9‐dien‐2‐one (4). The tricyclic ketones 3 und 4 were shown to be products of intramolecular Diels‐Alder addition in the intermediate 2,4,6‐trimethyl‐6‐(penta‐2,4‐dienyl)cyclohexa‐2,4‐dien‐1‐one (5). Preparation of 2,6‐methyl‐6‐(3‐methyl‐penta‐2,4‐dienyl)‐cyclohexa2,4‐dien‐1‐one (6) and subsequent heating of 6 in benzene gave the homotwistanone derivative 1,3‐6‐trimethyl‐tricyclo5.4.0.0^3,9^]undeca‐5,10‐dien‐2‐one (7) together with its isomer 1,3,6‐trimethyl‐tricyclo[5.3.1.0^3,8^]undeca‐5,9‐dien‐2‐one (8) in good yield.