Structural Modifications at the C3 and C30 Positions of the Lupane Skeleton with Carbon-Centered Nucleophiles

Lupeol, a naturally occurring pentacyclic triterpenoid widely distributed in various medicinal plants, has attracted significant attention due to its diverse pharmacological properties. In this study, we report the synthesis and structural modification of 14 lupeol derivatives through selective functionalizations at C3 and C30 positions of the lupane skeleton, via the sequential chemoselective introduction of carbonyl moieties and the addition of organometallics. Emphasis has been given to the stereoselective alkylation at C3 using a range of carbanions, including organolithiums, organomagnesiums and organoindiums. The C30 position was modified through oxidative pathways to introduce several functionalities.