Synthesis of 5-Iodo-1,2,3-triazoles from Organic Azides and Terminal Alkynes­: Ligand Acceleration Effect, Substrate Scope, and Mechanistic Insights

David N. Barsoum; Christopher J. Brassard; Jason H. A. Deeb; Najeah Okashah; Kesavapillai Sreenath; J. Tyler Simmons; Lei Zhu

doi:10.1055/s-0033-1339312

Synthesis, Table of Contents

Synthesis 2013; 45(17): 2372-2386
DOI: 10.1055/s-0033-1339312

feature article

Synthesis of 5-Iodo-1,2,3-triazoles from Organic Azides and Terminal Alkynes: Ligand Acceleration Effect, Substrate Scope, and Mechanistic Insights

David N. Barsoum

Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-4390, USA Fax: +1(850)6448281 Email: lzhu@chem.fsu.edu

,

Christopher J. Brassard

Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-4390, USA Fax: +1(850)6448281 Email: lzhu@chem.fsu.edu

,

Jason H. A. Deeb

Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-4390, USA Fax: +1(850)6448281 Email: lzhu@chem.fsu.edu

,

Najeah Okashah

Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-4390, USA Fax: +1(850)6448281 Email: lzhu@chem.fsu.edu

,

Kesavapillai Sreenath

Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-4390, USA Fax: +1(850)6448281 Email: lzhu@chem.fsu.edu

,

J. Tyler Simmons

Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-4390, USA Fax: +1(850)6448281 Email: lzhu@chem.fsu.edu

,

Lei Zhu*

Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, FL 32306-4390, USA Fax: +1(850)6448281 Email: lzhu@chem.fsu.edu

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Abstract

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Abstract

An improved method has been developed for the preparation of 5-iodo-1,2,3-triazoles directly from organic azides and terminal alkynes by a reaction mediated by copper(I) and iodinating agents generated in situ. The major methodological advance of the current procedure is that it provides a high conversion and good iodo/proto selectivity with a broad range of substrates without using an excess of the alkyne, which was required in the previous method. The use of an accelerating ligand is essential to the success of reactions involving unreactive azides or alkynes. New mechanistic insights are provided, including the confirmation that a 1-iodoalkyne is formed as a key intermediate under the established conditions for the reaction.

Key words

azides - alkynes - copper - catalysis - heterocycles - cyclizations - triazoles - halogenation - iodine

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References

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Supplementary Material

Supporting Information

Synthesis of 5-Iodo-1,2,3-triazoles from Organic Azides and Terminal Alkynes­: Ligand Acceleration Effect, Substrate Scope, and Mechanistic Insights

Synthesis of 5-Iodo-1,2,3-triazoles from Organic Azides and Terminal Alkynes: Ligand Acceleration Effect, Substrate Scope, and Mechanistic Insights