Enantiopure laterally functionalized alleno-acetylenic macrocycles: synthesis, chiroptical properties, and self-assembly in aqueous media.

A family of shape-persistent alleno-acetylenic macrocycles (SPAAMs), peripherally decorated with structurally diverse pendant groups, has been synthesized and characterized in enantiomerically pure form. Their electronic circular dichroism (ECD) spectra feature a strong chiroptical response, which is more than two times higher than for open-chain tetrameric analogues. A water-soluble oligo(ethylene glycol)-appended SPAAM undergoes self-assembly in aqueous solution. Morphology studies by cryogenic transmission electron microscopy (cryo-TEM) revealed the formation of aggregates with fibrous fine structures that correspond to tubular, macrocyclic stacks.