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.