Chemoenzymatic total synthesis of hyperiones A and B
Chicco Manzuna Sapu1, Jan Deska
1Department für Chemie, Universität zu Köln, DE-50939 Cologne, Germany.
Abstract:
The first asymmetric total synthesis of hyperiones A and B, two norlignans from Hypericum chinense, has been accomplished following a chemoenzymatic approach. Key features of this synthesis include the lipase-catalyzed enantioselective desymmetrization of a prochiral allenic diol and a silver-mediated cycloisomerization of the resulting axially chiral product to furnish the furan core structure. Two alternative pathways, a ruthenium-catalyzed redox isomerization on the one side and a platinum-catalyzed hydrogenation on the other, are described to finally obtain the desired norlignans.
Related Concept Videos
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis
Production of Pharmaceuticals
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Synthesis of α-Substituted Carbonyl Compounds: The Stork Enamine Reaction


