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Polar Substituents in Benzobarrelene Photochemistry; The Photoreactivities of Dimethyl 10‐methoxy‐ and Dimethyl 10,11‐dimethoxy‐2,3‐benzobicyclo[2.2.2]octateraene‐5,6‐dicarboxylate
Author(s) -
Bender Christopher Owen,
Wilson John
Publication year - 1976
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19760590508
Subject(s) - chemistry , benzophenone , cyclooctatetraene , methane , photochemistry , acetone , medicinal chemistry , organic chemistry , molecule
The direct irradiation of the monomethoxybarrelene 8 gives cyclooctatetraene product 18 (Φ = 0.075) via the anti ‐Epiotis aromatic‐vinyldiester [2π+2π] bridging route, and two semibullvalenes 16 (Φ = 0.075) and 17 (Φ = 0.075) from di‐π‐methane rearrangements initiating from vinyl‐vinyldiester bridging. Benzophenone sensitization yields 16 (Φ =0.11) and 17 (Φ = 0.11). The dimethoxybarrelene 9 gives only semibullvalene 10 , this resulting from di‐π‐methane rearrangement involving the vinyl and vinyldiester bridges, upon direct (Φ = 0.009) or benzophenone sensitized irradiations (Φ = 0.38). 10 undergoes a vinylcyclopropane rearrangement to give semibullvalene 11 upon direct or acetone sensitized irradiations (Φ = 0.008).