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.