2,8- and 2,9-Diboryltetracenes as Useful Building Blocks for Extended π-Conjugated Tetracenes

Ir-catalyzed direct diborylation of tetracene gave a 1:1 mixture of 2,8- and 2,9-bis[(pinacolato)boryl]tetracenes, which were separated by recrystallization. These diboryltetracenes are useful building blocks for the regiospecific synthesis of extended π-conjugated tetracenes directed to semiconductors for organic field-effect transistors (OFETs). Syntheses of thiophene−tetracene−thiophene, thiophene−tetracene−bithiophene−tetracene−thiophene, and thiophene−tetracene−anthracene−tetracene−thiophene π-systems have been achieved on the basis of the 2,8- and 2,9-diboryltetracenes.