Water-Compatible Synthesis of 1,2,3-Triazoles under Ultrasonic Conditions by a Cu(I) Complex-Mediated Click Reaction

A new
monophosphine Cu­(I) complex bearing bis(pyrazolyl)­methane
(L1) (CuIL1PPh3) was synthesized
and used as a catalyst for the three-component click reaction from
an alkyl halide, sodium azide, and terminal alkyne to furnish 1,4-disubstituted
1,2,3-triazoles in up to 93% yield. The catalyst is highly stable,
compatible with oxygen/water, and works with total efficiency under
ultrasonic condition. The structure of the complex was studied and
confirmed by X-ray crystallography, finding a riveting relationship
with its catalytic activity. This sustainable triazoles synthesis
is distinguished by its high atom economy, low catalyst loading (up
to 0.5 mol %), broad substrate scope, short reaction times, operational
simplicity, and an easy gram-scale supply of a functionalized product
for subsequent synthetic applications.