Sonogashira reactions for the synthesis of polarized pentacene derivatives

Five dissymmetrically functionalized anthracene analogues (3a-e) were synthesized from commercially available 9,10-dibromoanthracene through an efficient bromine iodine exchange followed by two successive Sonogashira coupling reactions. The resulting TMS-anthracene analogues are interesting building blocks for the preparation of highly pi-conjugated dissymmetric pentacene-based dyads, which could be used as active semiconducting layers for organic field-effect transistors (OFETs).