Triple Oxa[7]helicene with Circularly Polarized Luminescence: Enhancing the Dissymmetry Factors via Helicene Subunit Multiplication

The development of multiple heterohelicenes with a high luminescence dissymmetry factor (g(lum)) is an appealing yet challenging task. Herein, we disclose the synthesis of a structurally unusual furan-based triple oxa[7]helicene, which represents the first reported triple hetero[7]-helicene, via [2+2+2] cyclotrimerization/intramolecular dehydrogenative annulation. Compared to the reported double oxa[7]helicene, the triple oxa[7]helicene exhibits an improved g(lum) value of 1.8 x 10(-3), exemplifying the potential of the helicene subunit multiplication approach to enhance the g(lum) of heterohelicenes.

Automated summary

The synthesis of a structurally unusual triple oxa[7]helicene was disclosed in this study, showing an improved luminescence dissymmetry factor (g(lum) value compared to double oxa[7]helicene. This exemplifies the potential of the helicene subunit multiplication approach to enhance the g(lum) of heterohelicenes.