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A Facile and Versatile Approach to Double N‐Heterohelicenes: Tandem Oxidative CN Couplings of N‐Heteroacenes via Cruciform Dimers
Author(s) -
Sakamaki Daisuke,
Kumano Daisuke,
Yashima Eiji,
Seki Shu
Publication year - 2015
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201500684
Subject(s) - cruciform , tandem , oxidative phosphorylation , chemistry , combinatorial chemistry , stereochemistry , nanotechnology , materials science , biochemistry , composite material
Abstract Novel double N‐hetero[5]helicenes that are composed of two nitrogen‐substituted heteropentacenes are synthesized by tandem oxidative CN couplings via the cruciform heteropentacene dimers. The developed method is very facile and enables the synthesis of a double helicene in only two steps from commercially available naphthalene derivatives. These double N‐hetero[5]helicenes have larger torsion angles in the fjord regions than typical [5]helicenes, and optical/electrochemical measurements revealed a significant increase in the electronic communication between the two heteropentacene moieties of the double helicenes compared with their cruciform dimers. The optical resolution of one of the double helicenes was successfully carried out, and their stability towards racemization was remarkably higher than those of typical [5]helicenes. The synthetic strategy proposed in this paper should be versatile and widely applicable to the preparation of double helicenes from other N‐containing π‐conjugated planar molecules.