Regioselectivity in the Scholl Reaction: Mono and Double [7]Helicenes
Mohammad Mosharraf Hossain1, Khushabu Thakur1, Marat R Talipov1
1Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1414, United States.
Abstract:
We employed the density functionaly theory (DFT)-predicted regioselectivity of the intramolecular Scholl reaction in phenanthrene and dibenzo[g,p]chrysene frameworks to obtain π-extended mono and double [7]helicenes, respectively. The formation of these helical structures occurs despite the buildup of a large strain energy up to 30 kcal/mol compared with their most stable isomers. The twisted and strained structures were characterized and analyzed by experimental (NMR, UV-vis, emission, electrochemistry, and single-crystal X-ray diffraction) techniques and were further supported by DFT calculations.
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