The Intramolecular [3+2] Cycloaddition Reaction Was Designed To Synthesize A Series Of Fused 1,2,3-triazole Derivatives

1,2,3-Triazoles,as an important type of nitrogen heterocyclic compounds,have been used in wide areas such as material science,industrial applications and drug discovery in recent years.so its application and its synthesis method has always been develepded at present.A series of different types of fused triazole compounds were synthesized using propargyl alcohol and organic azides through propargyl cation-mediated intramolecular metal-free[3+2]azide-alkyne cycloadditions reaction.This method can accept both terminal and internal alkynes under mild conditions.First,4-pentyn-1-ol reacted with different ketones or aldehydes.Subsequently,propargyl azide was synthesized by nucleophilic reaction with NaN₃.Via propargyl cations derived from the corresponding alcohols,toluenesulfonic acid was effective in most cases and was demonstrated the desired fused-triazoles within 30 min in good yields under mild reaction conditions.The reaction system has high yield and mild conditions,which provides a new synthesis method for synthesizing a series of fused 1,2,3-triazoles.Further,different types of acetylenic alcohols were explored to synthesize the corresponding fused ring or heterocyclic fused 1,2,3-triazole compounds.On the one hand,alkynols containing different carbon numbers were used,on the other hand,the corresponding heteroatom-containing alkynols are obtained by the nucleophilic reaction of propargyl bromide with ethylene glycol,1,3-propanediol,1,4-butanediol,3-mercapto-1-ol.The different azido-propargyl alcohols were synthesized by a similar series of reactions as described above.Finally,under mild conditions,the corresponding macrocyclic or heterocyclic fused-triazole derivatives were synthesized by intramolecular metal-free[3+2]azide-alkyne cycloadditions.This method can provide a new convenient preparation of fused1,2,3-triazoles and explore their uses in synthetic organic.