✦ LIBER ✦
Photochemical Reactions. 128th Communication. Isolation of a Thermally Labile 2,8-Dioxabicyclo[3.2.1]oct-3-ene Intermediate on Photolysis of 3,4: 5,6-Diepoxy-5,6-dihydro-β-ionone
✍ Scribed by Norbert Bischofberger; Bruno Frei; Oskar Jeger
- Publisher
- John Wiley and Sons
- Year
- 1983
- Tongue
- German
- Weight
- 372 KB
- Volume
- 66
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
Photolysis (λ = 254 mm, THF) of the diepoxyenone (E)‐1 at −78° leads to the 2,8‐dioxabicyclo[3.2.1]oct‐3‐ene intermediate 3 (51%). At ambient temperature 3 undergoes an unexpectedly rapid electrocyclic opening to the triketone 2 in quantitative yield. Compound 3 seems likely to be the intermediate in the acid‐catalyzed rearrangement of (E)‐1 → 18 also.