European Journal of Organic Chemistry
Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Electronically Connected [n]Helicenes: Synthesis and Chiroptical Properties of Enantiomerically Pure (E)-1,2-Di(helicen-2-yl)ethenes (Eur. J. Org. Chem. 16/2013)
The cover picture showstwo enantiomerically pure helicene dimers. One is linked by an ethane-1,2-diyl moiety, whereas the other features an ethene-1,2-diyl bridge connecting the helicenes electronically. Intriguingly, the peaks of the electronic circular dichroism (ECD) traces of the latter feature values almost three times larger compared to those of the former, which exhibits values in the same order of magnitude as monomeric helicenes. Synthesis, extensive analysis of the chiroptical properties (both experimentally and computationally), and attempts to convert the stilbenoid helicene dimer into helicene are discussed in the article by F. Diederich et al. on page 3223 ff.