Linear and Angular Heteroacenes from Double-Electrophilic Cyclization (DEC) and DEC-Reductive Elimination of Diynes

Linear and angular heteroacenes are prepared from terminal alkynes bearing tethered nucleophiles in two steps. Linear heteroacenes are formed from the homocoupling of these alkynes followed by reaction with a double electrophile (ECl₂) to induce a tricyclization reaction cascade involving double-electrophilic cyclization (DEC). Related angular heteroacenes are formed from the prior substitution of the chloro groups in ECl₂ with the same terminal alkyne followed by reaction with AuCl₃ to produce a DEC-reductive-elimination (DECRE) reaction.