A chemoenzymatic total synthesis of (+)-clividine.

The title compound, ent-1, the non-natural enantiomeric form of the lycorenine-type alkaloid (-)-clividine (1), has been prepared using the enantiomerically pure (ee >99.8%) cis-1,2-dihydrocatechol 3 as starting material. A key feature associated with the closing stages of the synthesis involved the diastereoselective addition of a nitrogen-centered radical onto a pendant cyclohexene to establish the cis-fused D-ring and the required stereochemistry at C11b in the final product ent-1.