Diethyl 2,7-Dibromo-4H,5H- thieno[3,2-b:4,5-b‘]dipyrrole-3,6- dicarboxylate:  A Key Intermediate for a Diversity Oriented Synthesis of 2,7,12,17-Tetraarylporphycenes

A new Suzuki-based strategy for the synthesis of 4,4‘-diaryl (or heteroaryl)-substituted 2,2‘-bipyrroles (10), precursors of 2,7,12,17-tetraaryl (or heteroaryl)-substituted porphycenes, is described. Bromination of the previously described diethyl 4H,5H-thieno[3,2-b:4,5-b ‘]dipyrrole-3,6-dicarboxylate afforded dibromo compound 19, which is the key intermediate of such strategy.