Asymmetric synthesis of polyacetate derived building blocks with α-oxyanion functionality. Lewis acid catalyzed opening of 2,9-dioxabicyclo[3.3.1]nonan-3-ones

✍ Scribed by Ralf Dunkel; H.M.R Hoffmann

• Publisher: Elsevier Science
• Year: 1999
• Tongue: French
• Weight: 868 KB
• Volume: 55
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(99)00460-3

✦ Synopsis

All four stereoisomeric cyclic 3,5,7-trihydroxyheptanoic acid equivalents of the polyacetate aldol type (Scheme 1) are obtainable from 8-oxabicyclo[3.2.1]oct-6-en-3-one which functions as a meso-configurated 4-way optical switch. Lewis acid assisted nucleophilic ring opening of anomeric [3.3.1] oxabicyclic lactonas is a key step.

The utility Of the methodology is exemplified by a 6 step synthesis of the C17-C23 fragment of spongistatin (altohyrtin) and C-glycoside analogues.