Recent topics on synthesis of π-extended polycycles by cascade annulations

The development of new and efficient synthetic methodologies is regarded as one of the most streamlined approaches for the discovery of novel π-extended polycycles. This digest focuses on the illustration of recent advances on the synthesis of a variety of highly π-extended polycycles, including polyaromatic hydrocarbons, polyheteroaromatics, antiaromatic acene-type polycycles, by cascade annulation processes. The cascade annulation reactions presented in this digest mainly involve two strategies; Pd-catalyzed aromatic C[sbnd]H arylation through the formation of palladacycle species, and single electron oxidative annulation of methylenefluorenes.