Regio- and Stereoselective Synthesis of Thiazole-Containing Triarylethylenes by Hydroarylation of Alkynes

Thiazole-containing π-conjugated moieties are important structural units in the development of new electronic and photochromic materials. We have developed a Pd-catalyzed syn-hydroarylation reaction of diaryl alkynes with thiazoles that provides access to thiazole-containing triarylethylenes. Pd­(II) complexes derived from Pd(0) species and carboxylic acids facilitated C–H functionalization of the unsubstituted thiazole with high C5 selectivity. The catalytic system was also compatible with other azoles, such as oxazoles and a pyrazole, allowing the stereoselective syntheses of various trisubstituted olefins.