Short Synthesis of Alkyl-Substituted Acenes Using Carbonyl-Directed C–H and C–O Functionalization

A convenient method for the synthesis of tetraalkylanthracenes and -pentacenes by means of ruthenium-catalyzed regioselective C–H alkylation of the corresponding acenequinones was developed. Dialkyldiarylpentacene was also synthesized using chemoselective tandem C–H alkylation/C–O arylation of dimethoxypentacenequinone. It was suggested that a tetraalkylpentacene is stable under air in the dark and possesses an appropriate HOMO level as active material for p-type organic field-effect transistors (OFETs).