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Heterocyclic Spiro‐naphthalenones. Part II. Synthesis and reactions of some spiro [tetrahydrofuran‐2,1′‐(2′ H ‐naphthalene)]‐2′,5‐diones and Spiro [tetrahydrofuran‐2,2′‐(1′ H ‐naphthalene)]‐1′,5‐diones
Author(s) -
Berney Daniel,
Schuh Karlheinz
Publication year - 1978
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.19780610423
Subject(s) - chemistry , tetrahydrofuran , naphthalene , triethylamine , lactone , allylic rearrangement , medicinal chemistry , carboxylate , organic chemistry , catalysis , solvent
The spiro‐lactone 3 was obtained by N ‐bromosuccinimide (NBS) oxidation of the carboxylate 2 at − 20°. When 2 was oxidized at 10° the spiro‐lactone 4 was the main product. Compound 4 was rearranged with triethylamine to the spiro‐lactone 9 whereas the stereoisomeric spiro‐lactones 14 and 15 were obtained by NBS oxidation of the carboxylate 13 . The ketones 3, 4, 9, 14 and 15 were reduced with NaBH 4 to the corresponding alcohols 5, 6, 10, 16 and 18 respectively; these were hydrogenated to the alcohols 7, 8, 11 and 20 . The allylic alcohols 5 and 6 gave the benzochromanone 1 when heated in polyphosphoric acid whereas the benzochromanones 12 and 21 were obtained from the alcohols 10 and 16 respectively.