Combined Ugi-4CR/CuAAC Approach to Triazole-Based Neoglycolipids

New glycolipids that feature a carbohydrate/triazole/lipid hybrid architecture were readily produced by a combined multicomponent/click approach. The process comprises the use of the Ugi four-component reaction to construct double-lipidic scaffolds that have either alkyne or azide functionalities followed by conjugation to mono- and trisaccharides through a Cu-I-catalyzed 1,3-dipolar cycloaddition (click) process. The high chemical efficiency and feasibility of the over-all procedure provides new opportunities for the rapid creation and biological screening of libraries of this unique class of Ugi/click glycolipids. Dynamic NMR experiments were performed to evaluate the free energy of activation related to the isomerization of the cis/trans amide bond in these compounds. This is the first time that such multicomponent and cycloaddition processes have been combined for the synthesis of glycolipids.