Synthesis and Structural and Optical Behavior of Dehydrohelicene-Containing Polycyclic Compounds.

Dehydrohelicene-based molecules stand out as highly promising scaffolds and captivating chiroptical materials, characterized by their unique chirality. Their quasi-helical π-conjugated molecular architecture, featuring successively -annulated aromatic rings, endows them with remarkable thermal stability and optical properties. Over the past decade, diverse approaches have emerged for synthesizing these scaffolds, reinvigorating this field, with anticipated increased attention in the coming years.

Electrochemical synthesis of heterodehydro[7]helicenes.

Dehydrohelicenes are some of the most attractive chiroptical materials with unique helical chirality. However, to our knowledge, there are no prior reports on their direct construction by asymmetric methods. In this work, sequential synthesis of aza-oxa-dehydro[7]helicenes via the electrochemical oxidative hetero-coupling of 3-hydoxycarbazoles and 2-naphthols followed by dehydrative cyclization and intramolecular C-C bond formation has been realized.

Two-Step Synthesis, Structure, and Optical Features of a Double Hetero[7]helicene.

A novel double aza-oxa[7]helicene was synthesized from the commercially available ,-di(naphthalen-2-yl)benzene-1,4-diamine and -benzoquinone in two steps. Combining the acid-mediated annulation with the electrochemical sequential reaction (oxidative coupling and dehydrative cyclization) afforded this double hetero[7]helicene. Moreover, the structural and optical features of this molecule have been studied using X-ray crystallographic analysis, and the absorption and emission behaviors were rationalized based on DFT calculations.