Synthesis of Triazoles from Nonactivated Terminal Alkynes via the Three-Component Coupling Reaction Using a Pd(0)-Cu(I) Bimetallic Catalyst
Shin Kamijo, Tienan Jin, Zhibao Huo and Yoshinori Yamamoto*
*Department of Chemistry, Graduate School of Science, Tohoku University,
Sendai 980-8578, Email: yoshi
mail.tains.tohoku.ac.jp
S. Kamijo, T. Jin, Z. Huo, Y. Yamamoto, J. Am. Chem. Soc., 2003, 125, 7786-7787.
DOI: 10.1021/ja034191s
Abstract
Triazoles have been synthesized via a three-component coupling reaction of unactivated terminal alkynes, allyl carbonate, and trimethylsiyl azide under Pd(0)-Cu(I) bimetallic catalysis. The deallylation of the resulting allyltriazoles is described.
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proposed mechanism
Details
The document discusses the synthesis of 1,2,3-triazoles from nonactivated terminal alkynes using a Pd(0)-Cu(I) bimetallic catalyst. This method involves a three-component coupling (TCC) reaction between alkynes, allyl methyl carbonate, and TMSN3, followed by deallylation of the resulting allyltriazoles. The use of the Pd(0)-Cu(I) catalyst is crucial for promoting the [3 + 2] cycloaddition. The study found that CuCl(PPh3)3 was the most effective copper additive, yielding the highest amount of the desired product. Various terminal alkynes were tested, producing triazoles in good to moderate yields. The proposed mechanism involves the formation of a π-allylpalladium azide complex and a copper-acetylide, which undergo [3 + 2] cycloaddition to form the triazole framework. The method allows for the synthesis of triazoles that are not easily accessible through previous methodologies. The document also highlights the potential for extending this method to the synthesis of tetrazoles and other applications. Supporting information, including experimental procedures and compound characterization data, is available online.
Key Words
2H-1,2,3-Triazoles, Tsuji-Trost Reaction, Multicomponent Reactions, Click Chemistry
ID: J48-Y2003-1510
