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Intramolecular photoreactions of 4‐(ω‐alkenyloxy)‐6‐methyl‐2‐pyrones
Author(s) -
Shimo Tetsuro,
Yasuda Mitsuo,
Tajima Jun,
Somekawa Kenichi
Publication year - 1991
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570280332
Subject(s) - chemistry , intramolecular force , cycloaddition , isomerization , valence (chemistry) , hydrolysis , carbon chain , medicinal chemistry , stereochemistry , photochemistry , organic chemistry , catalysis
Abstract Photoirradiations of 4‐(ω‐alkenyloxy)‐2‐pyrones 1 gave site‐ and regio‐specific intramolecular [2 + 2]‐cycloadducts 2 being oxatricyclic lactones, and/or Dewar‐type valence‐isomer derivatives 4. The reaction path depended upon the alkenyl chain length. Namely the two or three carbon chain gave rise to intramolecular [2 + 2]‐cycloaddition, while the four carbon chain caused both valence‐isomerization and cycloaddition. Hydrolysis of the cycloadducts 2 gave oxabicycloalkanecarboxylic acids 7.