Chemistry: A European Journal 2006-10-10

(NHC)Copper(I)-catalyzed [3+2] cycloaddition of azides and mono- or disubstituted alkynes.

Silvia Díez-González, Andrea Correa, Luigi Cavallo, Steven P Nolan

文献索引：Chemistry 12 , 7558, (2006)

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摘要

A versatile and highly efficient catalyst for the Huisgen cycloaddition reaction has been developed. Previously isolated or in situ generated azides yielded 1,2,3-triazoles with differently substituted alkynes in the presence of a [(NHC)CuBr] complex (NHC = N-heterocyclic carbene). Extremely high reaction rates and excellent yields were obtained in all cases. This catalytic system fulfils the requirements of "click chemistry" with its mild and convenient conditions, notably in water or solvent free reactions and simple isolation with no purification step. Furthermore, for the first time, an internal alkyne was successfully used in this copper-catalyzed cycloaddition reaction. DFT calculations on this particular system allowed for the proposition of a new mechanistic pathway for disubstituted alkynes.