| Popis: |
A synthesis of the marine labdane furanoditerpene (-)-marginatone 1 has been accomplished by a short sequence of reactions starting from (+)-coronarin E 5. The key step is the stereocontrolled-intramolecular electrophilic cyclisation of the (+)-dihydrocoronarin E 6, to the tetracyclic marginatane skeleton 7, which is subsequently functionalized by allylic oxidation to give 1. As (+)-coronarin E 5 was previously synthesized from (-)-sclareol 10, the herein reported preparation constitutes the first formal total synthesis of (-)-marginatone 1, by which its absolute configuration has been confirmed. © 2005 Elsevier Ltd. All rights reserved. |
