An Enantioselective Organocatalytic Approach toBoth Enantiomers of Lasubine II

摘要

A concise stereoselective route providing access to bothenantiomers of the bioactive quinolizidine alkaloid lasubineII has been developed. The enantioselectivity was introducedby taking advantage of a proline-catalyzed asymmetricMannich reaction. Next, the bicyclic system was constructedvia a diastereoselective Mannich cyclization and subsequentring-closing metathesis as the key steps.