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DOI: 10.1055/s-1999-2965
Regioselective Base-induced Ethereal Bridge Openings of 7-Oxabicyclo[2.2.1]heptane-2,3-dicarboxylic Derivatives; Synthesis of Squalestatin Core Analogues
Publikationsverlauf
Publikationsdatum:
31. Dezember 1999 (online)
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The Diels-Alder adduct of furfuryl alcohol and maleic anhydride was converted into dimethyl 5-exo,6-exo-dihydroxy-1-{[tris(isopropyl)silyloxy]methyl}-7-oxabicyclo[2.2.1]heptane-2-exo,3-exo-dicarboxylate (12). Regioselective monosilylation of diol 12 gave the 5-O-(tert-butyl)dimethylsilyl ether 18. Under basic conditions the 7-oxanorbornane system of 18 was isomerized selectively into a 4,5,6-trihydroxy-6-(hydroxymethyl)cyclohex-2-ene-1,2-dicarboxylic derivative that was converted into a doubly-branched hepturonic acid derivative (24), potential precursor for the preparation of squalestatin core analogues.
dioxoheptanoic acid - hepturonic acid - ketoester selective reduction - 7-oxabicyclo[2.2.1]heptane - oxepane - ozonolysis