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Published on: November 9, 2019
Two-Step Synthesis of Boron-Fused Double Helicenes
Takazumi Katayama1, Soichiro Nakatsuka1, Hiroki Hirai1
1Department of Chemistry, School of Science and Technology, Kwansei Gakuin University , 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan.
Abstract:
Novel boron-fused double [5]helicenes were synthesized from hexabromobenzene in two steps via Hart reaction and demethylative cyclization. The parent helicene shows excellent ambipolar conductivity, which can be explained by unique 3D π-stacking with a brickwork arrangement. Moreover, the introduction of four tert-butyl groups suppresses racemization, enabling optical resolution. The enantiomerically pure helicene shows deep blue fluorescence with Commission Internationale de l'Eclairage coordinates of (0.15, 0.08) and circularly polarized luminescence activity.
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