Cu-catalyzed N-alkynylation of imidazoles, benzimidazoles, indazoles, and pyrazoles using PEG as solvent medium

A facile and efficient Cu(I)-catalyzed cross-coupling method is described for preparing of N-alkynyl or N-bromoalkenyl heteroarenes from bromoalkynes. The studies have shown that poly(ethylene glycol) 400 (PEG400) has acted as both a Cu(I)-stabilizing ligand as well as a phase transfer solvent.