An Organocatalytic Azide-Aldehyde [3+2] Cycloaddition: High-Yielding Regioselective Synthesis of 1,4-Disubstituted 1,2,3-Triazoles

An organocatalytic azide–aldehyde [3+2] cycloaddition (organo‐click) reaction of a variety of enolizable aldehydes is reported. The organo‐click reaction is characterized by a high rate and regioselectivity, mild reaction conditions, easily available substrates with simple operation, and excellent yields with a broad spectrum of substrates. It constitutes an alternative to the previously known CuAAC, RuAAC, and IrAAC click reactions. Metal‐free click: A variety of commercially available aldehydes was used in the metal‐free organo‐click reaction with aryl azides to obtain 1,4‐disubstituted 1,2,3‐triazoles. The method constitutes an alternative to previously known metal‐catalyzed azide–alkyne cycloaddition reactions (AAC), such as CuAAC, RuAAC, and IrAAC. DBU=1,8‐diazabicyclo[5.4.0]undec‐7‐ene; DMSO=dimethyl sulfoxide.