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Photocyclization reactions. Part 4 . Synthesis of naphtho[1,8‐ bc ]‐furans and cyclohepta[ cd ]benzofurans using photocyclization of Ethyl 2‐(8‐Oxo‐5,6,7,8‐tetrahydro‐1‐naphthyloxy)acetates and ethyl 2‐(5‐Oxo‐6,7,8,9‐tetrahydro‐5 H ‐benzocyclohepten‐4‐yloxy)acetates
Author(s) -
Sharshira Essam Mohamed,
Iwanami Haruki,
Okamura Mutsuo,
Hasegawa Eietsu,
Horaguchi Takaaki
Publication year - 1996
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.5570330124
Subject(s) - chemistry , substituent , acetonitrile , medicinal chemistry , irradiation , stereochemistry , organic chemistry , physics , nuclear physics
Photocyclization reactions were carried out on ethyl 2‐(8‐oxo‐5,6,7,8‐tetrahydro‐1‐naphthyloxy)acetates 1a‐e and ethyl 2‐(5‐oxo‐6,7,8,9‐tetrahydro‐5 H ‐benzocyclohepten‐4‐yloxy)acetates 2a‐e in acetonitrile. Irradiation of 1a‐e gave naphtho[1,8‐ bc ]furanols 3a‐e and naphtho[1,8‐ bc ]furans 4a‐e in 33–83% yields and ethyl acrylates 5b‐d were produced in 3–25% yields during irradiation of 1b‐d . On the other hand, 2a‐e afforded cyclohepta[ ad |benzofuranols 6a‐e and cyclohepta[ ad ]benzofurans 7a‐e in 44–87% yields. Ethyl acrylates 8b‐d were also produced in 7–43% yields from irradiation of 2b‐d . Substituent effects on photocyclization and reaction pathways are discussed.