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|Type:||Artigo de periódico|
|Title:||Stereoselective Synthesis Of The Enantiomer Of The Novel Marine Diterpene Isoagatholactone, Ent-13(16),14-spongiadien-12α-ol, And The Parent Hydrocarbon Isocopalane From Methyl Isocopalate|
|Author:||De Miranda D.S.|
|Abstract:||The stereoselective syntheses of the novel structures ent-isoagatholactone (7), ent-13(16),14-spongiadien-12α-ol (8), and the hydrocarbon isocopalane (11) from the ready available methyl isocopalate (6a) are described (see Scheme I). Methyl isocopalate (6a) was converted into 12,14-isocopaladiene (27) by LiAlH4 reduction, mesylation, and elimination. A key step in the sequence was the photooxygenation of 6a and 27, which after reduction and chromatographic separation produced alcohols 18 and 28, respectively. Alcohol 18 was rearranged into lactone 19 followed by reductive opening into the diol 20, which upon oxidation produced ent-isoagatholactone (7). Alcohol 28 was in turn submitted to a second photooxygenation reaction, and the resulting unsaturated cyclic peroxide 29 was treated with ferrous sulfate to furnish 8. Isocopalane (11) was obtained from 6a when submitted to catalytic hydrogenation followed by LiAlH4 reduction, mesylation, and reductive cleavage of the mesylate. The 1H and 13C NMR signal assignments for the synthesized products and intermediates are discussed. © 1981 American Chemical Society.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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