Polycyclic Aromatics via Cross-Coupling

cross-coupling - polycyclic aromatics - organic semiconductors

Significance

This report demonstrates a powerful method for the formation of functional poly­cyclic aromatic structures. These classes of ­structures are important building blocks for the formation of organic semiconductor materials. The high yields of the reactions suggest a practical method to produce quantities of materials and the (Z)-1,2-bis(pinacolatoboryl)stilbenes and related compounds are readily prepared from the ­biboryl and diarylalkynes (J. Chem. Soc., Dalton Trans. 2001, 1650).

Comment

Few cross-coupling reactions directly give new aromatic ring systems. The ability to ­incorporate both electron-rich (thiophene) and electron-poor (perfluoroaromatic) groups into the final products makes this method useful for the synthesis of a variety of useful organic semiconductors. The higher reactivity of the vicinal boryl groups is noteworthy and likely contributes to the ability to produce strained helicenes.