Stereoselective Transformation of the Alkaloid Lycorine to O-Demethylungiminorine and Ungiminorine

Abstract

Diacetyllycorine, an Amaryllidaceae alkaloid, was transformed stereoselectively to the more heavily oxygenated congener, O-demethylungiminorine, by a route similar to that suggested for the biosynthesis of narcissidine. Similarly, acetylhippamine was converted to ungiminorine. A method of high yield conversion of lycorine to hippamine is also described. The above transformations constitute a formal total synthesis of ungiminorine.