Towards functional fluorous surfactants. Synthesis of hydrophilic fluorous 1,2,3-triazolylmethyl ethers and di(1,2,3-triazolylmethyl) ethers

Copper(I)-accelerated Huisgen–Meldal dipolar cycloaddition reactions between polyfluoroalkyl azides and propargyl ethers of n-octanol and of triethyleneglycol monomethyl ether exhibited variation in yield of 1,2,3-triazol-4-ylmethyl ethers. Microwave acceleration, and in situ generation of the azides, provided improvements in yield and efficiency. In contrast, very good yields of equivalent fluorous triazoles were obtained from a range of n-alkyl azides with propargyl ethers of perfluorohexylethanol and of perfluoroheptylmethanol through conventional copper(I)-promoted reactions. Together, the resulting substances with systematic variations in polyfluoroalkyl and alkyl substituent length and position of substitution, and degree of oxygen content, make up small libraries of hybrid fluorous 1,2,3-triazol-4-ylmethyl ethers as candidates for study as hydrophilic fluorous surfactants. In addition, a pilot sample of di(1,2,3-triazol-4-ylmethyl) ethers with 1′-octyl-1-polyfluoroalkyl-substituents and 1′-nonyl-1-perfluorooctylethyl substituents were synthesised for the first time in an effort to develop more functional, fluorous surfactants.

Graphical abstractFluorous triazol-4-ylmethyl ethers and di(triazol-4-ylmethyl) ethers with systematically varying degrees of fluorination and oxygenation, substituent chain lengths and ring position have been synthesised by Cu(I)-induced Huisgen–Meldal dipolar cycloaddition. Microwave acceleration and in situ generation of azides have given yield advantages.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of 21 new fluorous triazol-4-ylmethyl ethers with systematically varied substituents. ► Demonstration of improved yields of 1-perfluoroalkylethyltriazoles by microwave acceleration and in situ generation of azides. ► First synthesis of symmetrical and unsymmetrical fluorous di(triazol-4-ylmethyl) ethers. ► Provision of hydrophilic fluorous 1,2,3-triazoles for study as surfactants.