Synthesis 1973; 1973(2): 71-84
DOI: 10.1055/s-1973-22136
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Role of Protic and Dipolar Aprotic Solvents in Heterocyclic Syntheses via 1,3-Dipolar Cycloaddition Reactions

Pankaja K. KADABA*
  • *Department of Pharmaceutical Chemistry, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40506, U. S. A.
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Publication History

Publication Date:
12 September 2002 (online)

This review surveys the role of protic and dipolar aprotic solvents in 1,3-dipolar cycloaddition reactions and explains how it could be used to advantage in heterocyclic syntheses. Special effort is made throughout the article to point out how protic and dipolar aprotic solvents affect the rates of cycloaddition reactions and how proper understanding and use of these solvent effects could help in performing many cycloadditions with synthetical applications and thus enhance the versatility and synthetic utility of these reactions in general. 1. Mechanism of 1,3-Dipolar Cycloadditions 1.1. Solvent and Substituent Effects 1.2. Protic and Dipolar Aprotic Solvent Effects 2. Applications 2.1. Investigation of Reaction Mechanisms 2.2. Heterocyclic Syntheses 3. Cycloadditions Involving Anionic 1,3-Dipoles 3.1. Direct 1,3-Cycloaddition of Azide Anion to C≡N Bonds and the Synthesis of Tetrazoles 3.2. Indirect 1,3-Cycloaddition of Azide Anion to Multiple Bonds