Oxidative construction of unusual indole-derived intermediates en route to conodusine A

Abstract

We describe several approaches to the tricyclic core of conodusine A. Synthesis of a macrocyclic alkene set the stage for 1,2-olefin difunctionalization with conodusine’s pendent amine. Unanticipated reactivity of an unusually labile indole mitigated the desired olefin manipulation. Efforts to pre-install the oxidation state at C19 before macrocyclic ring closure were met with unexpected results. Additionally, late stage allylic oxidation of the complete carbon skeleton of Conodusine was fraught with unforeseen challenges.