Efficient synthesis of 2-substituted-1,2,3-triazoles

In this three-component reaction, alkynes undergo a copper(I)-catalyzed cycloaddition with sodium azide and formaldehyde to yield 2-hydroxymethyl-2 H-1,2,3-triazoles, which are useful intermediates that can be readily converted to polyfunctional molecules. The hydroxymethyl group can also be removed, providing convenient access to N H-1,2,3-triazoles. The reaction is experimentally simple and readily scalable.