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.