[(NHC)2Cu]X Complexes as Efficient Catalysts for Azide-Alkyne Click Chemistry at Low Catalyst Loadings

摘要

In 2001, Sharpless and co-workers defined the concept of "click chemistry" and the criteria for a transformation to be considered a "click" reaction. Since then, the copper-catalyzed reaction of azides with alkynes to produce 1,2,3-triazoles regioselectively (the 1,3-dipolar Huisgen cyclo-addition) has become the most widely used click reaction. As a result of its mild conditions and high efficiency, this reaction has found a myriad of applications in biology and materials science. Less attention has been focused on the development of novel copper(I)-based well-defined catalytic systems and on decreasing the amount of copper used. This last point is extremely important for future industrial applications and might be one of the last challenges to overcome for this transformation.