Room-Temperature Organocatalytic Cycloaddition of Azides with β-Keto Sulfones: Toward Sulfonyl-1,2,3-triazoles.

Organocatalytic enamine-azide [3 + 2] cycloadditions between β-keto sulfones and aryl azides can be performed at room temperature in good to excellent yields of products in the presence of catalytic amounts of pyrrolidine (5 mol %). The proposed organocatalytic methodology was found to be applicable to β-keto arylsulfones containing a range of substituents. A wide variety of aryl azides also work. Basically, this constitutes a remarkably efficient protocol for the synthesis of novel 1,2,3-triazole compounds.