Exploiting the versatility of organometallic cross-coupling reactions for entry into extended aromatic systems

Using a variety of Pd-catalyzed cross-coupling techniques, we have prepared several pendant arene derivatives (5, 6, 12, 15). From these materials, we have expanded upon earlier work and developed new electrophilic cyclization strategies. By employing sufficiently strong electrophile sources, we may efficiently effect double annulations to afford polycyclic aromatics 10, 11, 13 and 16. This chemistry allows for the participation of both heteroaromatic and heteroatomic moieties thus providing an electronically diverse array of extended aromatic systems. (C) 2002 Elsevier Science B.V. All rights reserved.