The effects of ionic liquids on azide-alkyne cycloaddition reactions
作者:Stephen R. D. George、Gavin L. Edwards、Jason B. Harper
DOI:10.1039/c0ob00306a
日期:——
The effect of a series of ionic liquids on the regioselectivity of the azide-alkyne cycloaddition process was investigated, demonstrating an increased selectivity for the least hindered triazole. The effects of an ionic liquid on the activation parameters for the process were determined and found to be intermediate between coordinating and non-coordinating salts. The importance of knowing the water content of the system is demonstrated by marked changes in the activation parameters in the presence of small concentrations of water.
A simple and practical method for the synthesis of 1-alkyl-5-methyl ester-1H-1,2,3-triazole-5-carboxylate from low boiling point azides is demonstrated. The triazoles were constructed by 1,3-dipolar cycloaddition of methyl 3-(trimethylsilyl) propiolate with alkyl azides containing one to four carbons. To better handle the volatility of the alkyl azides, a flow chemistry method was developed to ensure