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


  • We are grateful to the Natural Sciences and Engineering Research Council of Canada (NSERC) for financial support. We thank L.-L. Tay (NRC, Ottawa) for the Raman spectra, also K. Fagnou, T. Moon, and S. Gorelsky for the DFT calculations, and M. Frenette for CD spectral measurements.


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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.