Organoelectrochemistry-Enabled Biomimetic Syntheses of Alstoscholarinoids A and B

We report efficient electrochemically enabled syntheses of natural products alstoscholarinoids A (<b>1</b>) and B (<b>2</b>). Employing oleanolic acid (OA) as the feedstock, gram-scale syntheses of biosynthetic precursors diene <b>3</b> (under AP mode) and lactone <b>4</b> (under DC mode) were achieved. Subsequent gram-scale transformations furnished <b>1</b> and <b>2</b> through singlet oxygen-mediated oxidative rearrangement of <b>3</b> and ozonolysis of <b>4</b> followed by an aldol/lactonization cascade, respectively. This strategy delivers <b>1</b> in 36% yield over two steps and <b>2</b> in 42% yield over three steps, establishing the most concise synthetic routes to these architecturally complex triterpenoids to date.