StereocontrolledSynthesis of the Portimine Skeletonvia Organocatalyst-Mediated Asymmetric Stannylation and StereoretentiveC(<i>sp</i>³)–C(<i>sp</i>²) 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(<i>sp</i>³)–C(<i>sp</i>²) 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.