Tandem epoxide or aziridine ring opening by azide/copper catalyzed [3+2] cycloaddition: efficient synthesis of 1,2,3-triazolo beta-hydroxy or beta-tosylamino functionality motif.

A novel and practical procedure for the synthesis of small molecules possessing beta-hydroxy or N-tosylamino 1,2,3-triazole motif by azidation of epoxides or N-tosylaziridines with sodium azide followed by "click reaction" using eco-friendly PEG-400 as a reaction medium in the presence of 5 mol % of CuI is described. Enantiomerically pure epoxide and N-tosylaziridines were afforded in high yield with excellent ee values maintaining complete stereospecificity.