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.