ABSTRACT Quasi T‐shaped three‐way benzo b thiophene scaffolds, containing iodine atom(s) at the 4‐ and/or 7‐position, were prepared by several methods including silica gel‐assisted cyclization, electrophilic substitution, nucleophilic substitution, or borylation. The iodobenzo b thiophenes thus prepared were subjected to Sonogashira cross couplings to give various ethynylbenzo b thiophenes. Benzo b thiophenes bearing different ethynyl groups in the molecule were also prepared, utilizing (bromo)(iodo)benzo b thiophenes. In addition, photophysical properties as well as theoretical calculations of some 4,7‐diethynylbenzo b thiophenes were studied.
Toyota et al. (Sun,) studied this question.