Nickel-catalyzed synthesis of oxazoles via C-S activation.

The synthesis of 2-substituted oxazoles is achieved via nickel-catalyzed cross-coupling reaction of 2-methylthio-oxazole and various organozinc reagents. An extension of this method is demonstrated with a chemoselective, one-pot synthesis of unsymmetrical 2,5-disubstituted oxazoles. This synthesis of 2- and 2,5-substituted oxazoles using this method provides great advantages over previous methods for these compounds and is highly complementary to current cyclodehydration strategies.