Total synthesis of (±)-aspidospermidine

(+/-)-Aspidospermidine (1) has been synthesized from readily available methyl 3-ethyl-2-oxocylopentanecarboxylate (17) in 5.9% yield over 13 steps. The key step of the synthesis is an intramolecular cascade reaction that simultaneously forms the B, C, and D rings of 1. A high-yielding method of closing the remaining E ring is also described.