Forging the Tetracyclic Core Framework of Daphlongamine B Enabled by a Peripheral Derivation of the Aza-Angular Triquinane Strategy

A synthetic route to the highly functionalized tetracyclic core framework of daphlongamine B is described. Key features of the strategy involve an oxidative dearomatization-induced [4+2] cycloaddition, a di-π-methane rearrangement, and a ring-closing metathesis reaction. Our approach enables the reliable construction of a fully elaborated tetracyclic precursor, which, in turn, provides valuable functional handles for further elaboration to the target molecule.