Coronenes with push-pull geometries from macrocycle-forming Perkin condensations

Although the Perkin reaction has been successful in producing ester-substituted conjugated macrocycles with four or six building blocks, macrocycles composed of only two elements remained elusive until now. Through the development of a building block derived from phenanthrene with two glyoxylic acid substituents in a pincer-like arrangement, formation of a two-block macrocycle was induced when paired with a complementary phenylenediacetic acid unit. The addition of ether functions to the phenanthrene building block not only improved the yields, but led to macrocycles with push-pull geometries. Photocyclisation of the resulting cyclophanes efficiently yield tetra- and hexasubstituted coronenes.