A novel effective transition metal based salt-catalyzed azidolysis of 1,2-epoxides

A simple, efficient, stereoselective, and in some cases usefully non-regioselective method for the synthesis of β-azido alcohols by the direct opening of 1,2-epoxides with 1,1,3,3-tetramethylguanidinium azide (TMGA) in CH3CN, catalyzed by simple transition metal-based salts [Hf(OTf)4, Zr(OTf)4, Yb(OTf)3], is described. Also TMSN3 may be used in some reactions as a source of N3−. This new method appears to be competitive with other methods previously reported.