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.
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.