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A Stepwise Huisgen Cycloaddition Process: Copper(I)-Catalyzed Regioselective Ligation of Azides and Terminal Alkynes

Vsevolod V. Rostovtsev, Luke G. Green, Valery V. Fokin*, K. Barry Sharpless

*Department of Chemistry and the Skaggs Institute for Chemical Biology The Scripps Research Institute, BCC-315 10550 N. Torrey Pines Rd., La Jolla, CA 92037, USA, Email:

V. V. Rostovtsev, L. G. Green, V. V. Fokin, K. B. Sharpless, Angew. Chem. Int. Ed., 2002, 41, 2596-2599.

DOI: 10.1002/1521-3773(20020715)41:14<2596::AID-ANIE2596>3.0.CO;2-4


The CuI-catalyzed, stepwise cycloaddition of azides to terminal alkynes exhibits broad scope and provides 1,4-disubstituted 1,2,3-triazoles in excellent yields and high regioselectivity.

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proposed mechanism (updated mechanism)

the thermal reaction results in a mixture of the 1,4 and 1,5 regioisomers

Key Words

azides, copper, click chemistry, cycloaddition, homogeneous catalysis, nitrogen heterocycles, 1,2,3-triazoles

ID: J06-Y2002-940