CYTOCHALASIN SUPPORT STUDIES - MACROCYCLE SYNTHESIS VIA ENOLATE-ASSISTED, INTRAANNULAR 1,4-FRAGMENTATION REACTIONS

The intramolecular reactions of the four possible diastereomers of cis- and trans-fused 6α- and β-benzenesulfonoxy-4,4-dimethylbicyclo[5.4.0]undecan-3-one were examined. Conversion of these substances to their enolates caused the cis-β and trans-β isomers to form cyclobutanes by intramolecular alkylation. The cis and trans a isomers underwent fragmentation reactions to produce trans, cis- and trans, trans-11,11-dimethylcycloundeca-2,8-dienone, respectively. These dienones could not be directly isolated from the simple fragmentation reaction (because of dimer formation); however, when the fragmentation reaction was carried out in the presence of diisobutylaluminum hydride, the corresponding dienols were isolated in >90% yield. The mechanisms of these reactions are discussed as well as their applicability to cytochalasin synthesis. Copyright © 1979, American Chemical Society. All rights reserved.