Synthesis and Structures of Multifunctionalized Helicenes and Dehydrohelicenes: An Efficient Route to Construct Cyan Fluorescent Molecules

Spiral up! A series of multifunctionalized benzo[5]helicene derivatives and a benzo[7]helicene were conveniently synthesized. Moreover, the oxidative cyclodehydrogenation of the benzo[5]helicenes by DDQ in trifluoroacetic acid or trifluoromethanesulfonic acid quantitatively provided the corresponding dehydro[5]helicene derivatives, which showed the cyan fluorescent properties (shown here).