Palladium Immobilized on Thiol-Modified Silica Gel for Effective Direct C-H Arylation.

Abstract

A palladium catalyst immobilized on thiol-modified silica gel (PITS) was developed for the efficient synthesis of various π-conjugated oligomers and polymers. Direct arylation of 3,4-ethylenedioxythiophene (EDOT) gave not only the corresponding oligomeric compounds in high yields but also high-molecular-weight π-conjugated polymers in high yields. Moreover, the polycondensation of the β-unprotected bithiophene monomer with dibromoarenes was also achieved. This solid-supported Pd catalyst was used to conduct regioselective direct arylation polycondensation, giving high-molecular-weight π-conjugated polymers in high purity (low levels of residual Pd impurities and structural β-defects).