Solid-Phase Synthesis of Oligo[(1,4-phenyleneethynylene)-alt-(2,5-thiopheneethynylene)]s

Significance

Monodisperse oligo[(1,4-phenyl­eneethynylene)-alt-(2,5-thiopheneethynylene)]s were synthesized via an iterative divergent/convergent doubling strategy on resin. Thus, the resin-supported terminal acetylene 1 reacted with compound 2 in the presence of Pd/Cu catalyst to give the desired ‘starting monomer’ 3 for the iterative divergent/convergent doubling strategy. One third of 3 was subjected to desilylation with TBAF to give the resin 4. Two thirds of 3 were treated with MeI to afford 5 in 77% yield. Resin 4 reacted with 5 in the presence of Pd/CuI to give resin 6. The sequence was repeated to generate resin 9, which was treated with MeI to give octamer 10 in 37% yield over three steps.