Catalytic, Enantioselective Formal Synthesis of Monoterpene Indole Alkaloid (-)-Alstoscholarine.

A catalytic, enantioselective formal synthesis of monoterpene indole alkaloid (-)-alstoscholarine is described. The synthesis employs an Ir-amine dual catalyzed asymmetric allylation of aldehyde 8 with 3-indolyl vinyl carbinol derivative 7 to furnish chiral aldehyde 6 as a key asymmetric step. Other key reactions include the construction of the 2-ketopyrrole moiety by Nicolaou's method and Tf2O promoted Pictet-Spengler cyclization to access Zhu's intermediate 3.