New methods for the synthesis of 4<i>H</i>‐dithieno[3,2‐<i>b</i>:2′,3′‐<i>d</i>]pyrrole

Abstract

Abstract Various alternative methods for the synthesis of 4 H ‐dithieno[3,2‐ b :2′,3′‐ d ]pyrrole (DTP) starting from commercially available bromothiophene precursors are presented. Crucial steps involve the Cadogan reaction, Ullmann‐type C─N couplings, or Buchwald‐Hartwig–type aminations to build up the central pyrrole ring of DTP, respectively. The use of ammonia surrogates afforded the fused target heteroacene in overall yields of 33% to 63%, and the corresponding methods are applicable on large scale.