The successful application of the nickel catalyzed, intramolecular [4+4] cycloaddition of bisdienes to the preparation of both the AB and BC ring systems of the taxane diterpenes is described. This cycloaddition methodology provides the basis for a general and efficient route to angularly alkyl-subs
A Diene-Transmissive Approach to the Quassinoid Skeleton.
β Scribed by Claude Spino; Bryan Hill; Pascal Dube; Stephane Gingras
- Publisher
- John Wiley and Sons
- Year
- 2003
- Weight
- 54 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0931-7597
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π SIMILAR VOLUMES
Hydroxypicrasan-3-one, a compound having the correct relative stereochemistry of al1 the six ring-juncture chira1 centers of the picrasane skeleton, was synthesized from a known tricyclic compound, using the orthoester Claisen rearrangement and lead tetraacetate oxidation as key reactions.
A novel and general approach has been delineated lor the enantiomerically pure synthesis of the angularly fused tricyclic system of the pentalenolactone family of compounds. D-Glucose is used as starting material and a diasteroselective Diels-Alder reaction sets the elements for the ring junctions.
A Diene Transmissive Diels-Alder Strategy for Oxygenated Nor-Steroid and Triterpenoid Skeletons. -Swern oxidation of the carbohydrate derived allylic alcohol (II) forms a ketone which cyclizes spontaneously to the diene (III), the stereochemistry of which is controlled by the isopropylidene acetal.