Key points are not available for this paper at this time.
reaction: see text A double helicene formed by a pentahelicene and a heptahelicene with two rings in common was obtained by palladium-catalyzed cyclotrimerization of 3,4-didehydrophenanthrene and was characterized conformationally by NMR and GIAO calculations.
Peña et al. (Sat,) studied this question.