Cu-catalyzed N-alkynylation of imidazoles, benzimidazoles, indazoles, and pyrazoles using PEG as solvent medium.
Burley GA, Davies DL, Griffith GA, Lee M, Singh K. Cu-catalyzed N-alkynylation of imidazoles, benzimidazoles, indazoles, and pyrazoles using PEG as solvent medium. J Org Chem. 2010 Feb 05; 75(3):980-3.