A Practical and Efficient Synthesis of Uniform Conjugated Rod‐Like Oligomers

Herein, a more practical and efficient synthesis protocol for the preparation of uniform rod-like oligo(1,4-phenylene ethynylene)s (OPE)s is presented. Applying an iterative reaction cycle consisting decarboxylative coupling saponification alkynyl carboxylic ester, pentamer obtained in ten steps with 14% overall yield. The copper-free conditions prevent homocoupling until trimer stage, resulting significantly easier work-up products. Homocoupling observed from tetramer stage on, but simple variation procedure also yields pentamer. A thorough comparison commonly used described Sonogashira approach reveals that new presented strategy, OPEs can be built similar yield, purification quarter time. All oligomers are fully characterized by proton carbon nuclear magnetic resonance spectroscopy (NMR), mass spectrometry (MS), size-exclusion chromatography (SEC), infrared (IR).