Key points are not available for this paper at this time.
A straightforward method for the octafunctionalization of biphenylene based on the 2+2-cycloaddition of an aryne intermediate has been developed. This enabled a "North-South" extension of biphenylene towards isomeric graphene nanoribbons composed of four-, six-, and eight-membered rings. This procedure furthermore allowed an "East-West" expansion to nphenylenes with different lengths. For the fabrication of isomeric nanongraphenes, octaarylbiphenylenes decorated with phenyl, pyrenyl, and thieno substituents were prepared. The subsequent oxidative cyclodehydrogenation provided an expanded helicene as a model compound.
Schlütter et al. (Mon,) studied this question.