Photochemische Reaktionen. 112. Mitteilung [1] Zur Photochemie α, β-ungesättigter γ, δ-Epoxyester. III. Ergänzende Untersuchungen zur Triplettreaktivität

✍ Scribed by Kazuo Murato; Bruno Frei; Wolfhard Bernd Schweizer; Hans Richard Wolf; Oskar Jeger

• Publisher: John Wiley and Sons
• Year: 1980
• Tongue: German
• Weight: 650 KB
• Volume: 63
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19800630712

✦ Synopsis

Abstract

On triplet sensitization (E)‐5 gives (Z)‐5 and isomerizes via C(δ), O‐bond cleavage to the cyclobutanone 6 and the conjugated γ‐ketoester 7. ‐ On singulet excitation 6 undergoes decarbonylation and yields the bicyclo [4.1.0]heptane 8. However, on triplet sensitization 6 is converted to the isomeric tricyclononane 9 by a stereospecific oxa‐di‐π‐methane rearrangement. The structure of 9 is determined by X‐ray analysis of the p‐nitrobenzoate 15: a = 10.573, b = 14.707, c = 13.494 Å, β = 112.40°, __P__2~1~/n, Z, = 4.