A Facile Asymmetric Synthesis of Corey Lactone Utilizing C2-Symmetric Dimethyl 3,7-Dihydroxy-cis-bicyclo[3.3.0]octan-2,6-diene-2,6-dicarboxylate
摘要:
Optically pure Corey lactone [(-)-1] was conveniently synthesized from an optically pure C-2-symmetric diester [(+)-3] which was prepared by lipase-catalyzed demethoxycarbonylation of bicyclic tetraester (2).
Lipase-catalyzed asymmetric demethoxycarbonylation: Formal syntheses of (+)-carbacyclin, (−)-ajmalicine, and (−)-tetrahydroalstonine
摘要:
Both enantiomers of C-2-symmetric dimethyl 3,7-dihydroxybicyclo[3.3.0]-octa-2,6-dicarboxylate 3 were prepared in enantiomerically pure form from symmetric tetraester 1 by the lipase-catalyzed demethoxycarbonylation, respectively. Double asymmetric differentiation with lipase in the above demethoxycarbonylation was observed. Their applications to formal total syntheses of (+)-carbacyclin and (-)-ajmalicine including (-)-tetrahydroalstonine are also described. (C) 1998 Elsevier Science Ltd. All rights reserved.
Both enantiomers of C2-symmetric dimethyl 3,7-dioxo-cis-bicyclo[3.3.0]-octane-2,6-dicarboxylate (3) were prepared in enantiomerically pure form by the lipase-catalyzed demethoxycarbonylation, respectively. An expeditious formal total synthesis of (+)-carbacyclin using this hybrid process was done.
New Asymmetric Syntheses of (-)-Isoiridomyrmecn 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).