Stereocontrolled Synthesis of the Portimine Skeleton via Organocatalyst-Mediated Asymmetric Stannylation and Stereoretentive C(sp3)–C(sp2) Stille Coupling

Our efforts toward the synthesis of the marine natural product portimine are described. The key to the synthesis of the skeleton is a stereoretentive copper-catalyzed C(sp³)-C(sp²) Stille-type cross-coupling that enables the convergent assembly of functionalized fragments. The core skeleton of portimine was constructed via ring-closing metathesis and transannular acetal formation.