Experimental and Theoretical MEDT Study of the Thermal [3+2] Cycloaddition Reactions of Aryl Azides with Alkyne Derivatives

Understanding the mechanism and regioselectivity of the copper(i) catalyzed [3 + 2] cycloaddition reaction between azide and alkyne: a systematic DFT study

The copper(I) catalyzed azide–alkyne [3 + 2] cycloaddition (32CA) reaction and its uncatalyzed version have been studied for systematic understanding of this relevant organic transformation, using DFT calculations at the B3LYP/6-31G(d) (LANL2DZ for Cu) computational levels. In the absence of a copper(I) catalyst, two regioisomeric reaction paths were studied, indicating that the 32CA reaction takes place through an asynchronous one-step mechanism with a very low polar character. The two reactive channels leading to 1,4- and 1,5-regisomer present similar high activation energies of 18.84 and 18.51 kcal mol−1, respectively. The coordination of copper(I) to alkyne produces relevant changes in …