Alkyl- or Aryl-Monosubstituted ,2,3-Triazoles

The direct addition of hydrazoic acid to acetylenes with electron-withdrawing groups can produce comparable yields of 1.1-1 (Eq. 2), but the safety problems are quite real. Acetylene itself can be converted to 1.1-1 in high yield through reaction with sodium azide under carefully controlled conditions (Eq. 3).  

The addition of trimethylsilylazide to the carbon-carbon triple bond (Eq. 4) is attractive both for safety and for the ease of removing the silyl group.  

With acetylene itself excellent yields have been reported. The thermal rearrangement of the trimethylsilyl group in 1.1-2 is well established. The presence of strong electron-withdrawing groups facilitates the reaction. The decarboxylation product (1.1-3) has been obtained quantitatively in dioxane.  

The safest and perhaps most generally applicable synthesis of 1-alkyl-1,2,3-triazoles relies on the nucleophilic character of the heterocyclic nitrogen atoms of 1.1-1 (Eq. 5). Gold has shown that with equimolar reactants, 1.1-4 and 1.1-5 are formed in a ratio of 4 1 whereas an excess of 

1- 1 (or its silver salt) produces a tower conversion and a greater excess of 

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