Intramolecular Borylation via Sequential B−Mes Bond Cleavage for the Divergent Synthesis of B,N,B‐Doped Benzo[4]helicenes |
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| Authors: | Julius A Knöller Guoyun Meng Dr Xiang Wang David Hall Anton Pershin Prof?Dr David Beljonne Dr Yoann Olivier Prof?Dr Sabine Laschat Prof?Dr Eli Zysman‐Colman Prof?Dr Suning Wang |
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| Institution: | 1. Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, K7L 3N6 Canada;2. Institute for Organic Chemistry, Stuttgart University, Pfaffenwaldring 55, 70569 Stuttgart, Germany;3. School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China;4. Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST UK;5. Laboratory for Chemistry of Novel Materials, University of Mons, 7000 Mons, Belgium;6. Unité de Chimie Physique Théorique et Structurale & Laboratoire de Physique du Solide, Namur Institute of Structured Matter, Université de Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium |
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| Abstract: | New symmetric and unsymmetric B,N,B‐doped benzo4]helicenes 3 – 6 a/b have been achieved in good yields, using a three‐step process, starting from N(tolyl)3 in a highly divergent manner (7 examples). A borinic acid functionalized 1,4‐B,N‐anthracene 1 was found to display unprecedented reactivity, acting as a convenient and highly effective precursor for selective formation of bromo‐substituted B,N,B‐benzo4]helicenes 2 a / 2 b via intramolecular borylation and sequential B?Mes bond cleavage in the presence of BBr3. Subsequent reaction of 2 a / 2 b with Ar‐Li provided a highly effective toolbox for the preparation of symmetrically/unsymmetrically functionalized B,N,B‐helicenes. Their high photoluminescence quantum yields along with the small ΔEST suggest their potential as thermally activated delayed fluorescence (TADF) emitters for organic light‐emitting diodes (OLEDs). |
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| Keywords: | B N B-benzo[4]helicenes boron divergent synthesis luminescence synthetic methods |
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