Catalytic Asymmetric Synthesis of the Pentacyclic Core of (+)-Citrinadin A
Barry M Trost1, Benjamin R Taft1, Jacob S Tracy1
1Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305, United States.
Abstract:
The synthesis of the pentacylic core of (+)-citrinadin A is described. Our strategy harnesses the power of palladium-catalyzed trimethylenemethane chemistry (Pd-TMM) to form the key spirooxindole motif in a catalytic, asymmetric fashion. Upon the conversion of this spirooxindole to a vinyl epoxide electrophile, the piperidine ring is directly added via a diastereoselective metalation followed by an SN2' addition. The final ring of the pentacyclic core is then formed through an intramolecular SN2 displacement of the resulting activated alcohol.
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