New Asymmetric Syntheses of (-)-Isoiridomyrmecin and (+)-Loganin Aglucon 6-Acetate Utilizing C2-Symmetric Dimethyl 3,7-Dihydroxy-cis-bicyclo[3.3.0]octa-2,6-diene-2,6-dicarboxylate.

The first asymmetric synthesis of (-)-isoiridomyrmecin and formal synthesis of (-)-loganin were done using chiral C2-symmetric building block dimethyl 3, 7-dihydroxy-cis-bicyclo[3.3.0]octa-2, 6-diene-2, 6-dicarboxylate (2) which was prepared by the lipase-catalyzed asymmetric demethoxy-carbonylation of tetramethyl 3, 7-dioxo-cis-bicyclo-[3.3.0]octane-2, 4, 6, 8-tetracarboxyrate (1).