Quaterpyrroles as Building Blocks for the Synthesis of Expanded Porphyrins

A new
family of quaterpyrroles and their application as building
blocks for the synthesis of macrocycles is reported. The preparation
of these quaterpyrroles consisted of two synthetic steps: bromination
of 2,2′-bipyrroles bearing two electron-withdrawing groups
followed by Suzuki coupling with 1-(tert-butoxy­carbonyl)­pyrrole-2-boronic
acid. The resulting quaterpyrroles have been used to prepare an octaphyrin
and a substituted cyclo[8]­pyrrole. Additionally, the synthesis of
a new macrocycle containing the quaterpyrrole and 2,5-di­(1H-pyrrol-2-yl)­thio­phene moieties is presented.