Asymmetric Allenophanes: Synthesis of a Tris‐meta‐allenophane and Tetrakis‐meta‐allenophane by Sequential Cross‐Coupling

Around and around: A strategy based on sequential Pd-catalyzed cross-coupling reactions was applied for the asymmetric synthesis of new macrocyclic meta-allenophanes composed of 18- or 24-membered rings (see structures). The chiral components, tertiary propargyl alcohols and allene bridges, were assembled by a general enantioselective protocol, which involved a Sharpless epoxidation, an oxidation, and Sonogashira cross-coupling.