Angular and Helical Phenylenes

Molecular models indicate that, starting with angular [6]phenylene, the two ends of the angular phenylenes suffer steric interactions that render them helical, an expectation that was quantified theoretically [65]. The hexagonal squeezes of these helical phenylenes (heliphenes) are helicenes, a dass of PAHs that has received much scrutiny [66]. 

Having demonstrated the feasibility of triple cycloisomerizations, synthetic schemes were once again developed that replaced the terminal benzene moieties with biphenylene, giving rise to 32 and 34, respectively. The former then provided 

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