Asymmetric Total Syntheses of (-)--Lycorane, (-)-Zephyranthine, and Formal Synthesis of (+)-Clivonine

An asymmetric route to (-)--lycorane and (-)-zephyranthine, and a formal total synthesis of (+)-clivonine were achieved. A pivotal intermediate, which serves as a potent precursor for the divergent syntheses of these natural products, was accessed by a diastereoselective Pd-catalyzed cinnamylation of an N-tert-butanesulfinyl imine.