Post‐Modification of Tripyrenylenes to Enantiopure π‐Extended <i>D</i> ₃ ‐Symmetric Propellers

ABSTRACT A palladium‐catalyzed trimerization of a pyrene‐based Kobayashi aryne precursor and post‐functionalization of the obtained tripyrenylene was used to synthesize polycyclic aromatic hydrocarbons with multiple helicene subunits. The isomerization of the obtained C 2 ‐isomers to the corresponding propeller‐shaped D 3 ‐isomers was investigated and the enantiomers of a D 3 ‐pyrenylene as well as a D 3 ‐trisphenanthrophenazine were isolated. Their chiroptical properties as well as the crystalline packings in comparison to the corresponding racemates were studied and the isomerization as well as racemization processes were investigated kinetically and by quantum chemical calculations.