Catalytic Selective Cyclizations of Aminocyclopropanes: Formal Synthesis of Aspidospermidine and Total Synthesis of Goniomitine

Mild control: Selective cyclization of aminocyclopropanes at either the N1 or C3 position of an indole ring was achieved by tuning the reaction conditions (see scheme). This strategy was applied to the formal synthesis of aspidospermidine and the total synthesis of goniomitine, which demonstrated significant cytotoxicity against several tumor cell lines (IC50=150–400 nM). Cbz=benzyloxycarbonyl, Ts=4-toluenesulfonyl.