A copper-based ionic liquid as inexpensive and efficient catalyst for the [3 + 2] cycloaddition of azides and terminal alkynes

A fast and single-step synthesis of the octahedral Cu[(OHCH2CH2)2NH]6[CF3SO3]2 ionic liquid is presented for use in click chemistry. The ionic liquid effectively catalyzes the [3 + 2] cycloaddition of azides and terminal alkynes to give 1,4-disubstituted 1,2,3-triazoles regioselectively with high yields, without requiring bases, reducing agents, or inert atmospheres. The scope and catalytic activity of this ionic liquid are described herein for the first time. In addition, the present cost effective catalytic system is impressive even under stirring free conditions.