Resolving the (19R) Absolute Configuration of Lanciferine, a Monoterpene Indole Alkaloid from Alstonia boulindaensis

Reinvestigation of the structure of lanciferine (1a) through extensive spectroscopic analysis in conjunction with a detailed computational study led to the unambiguous assignment of its (19R) absolute configuration, thus leading to the full (2R, 3S, 7S, 15R, 16R, 19R, 20S) assignment of lanciferine 45 years after its isolation.