Zn(NTf 2 ) 2 /NIS as a New Promoter System for Thioglycosides to Effectively Construct α-Galactosamines and α-Galactosazides

Zn(NTf 2 ) 2 in combination with N -iodosuccinimide provides a powerful promoter system, capable of activating 4, 6- O -di- tert- butylsilylene-thiogalactoamine and 4, 6- O -benzylidene-2-thiogalactoazide donors. The activation protocol is successfully applied to a wide range of alcohol acceptors, rendering excellent yields of α-galactosamines and α-galactosazides. This method features simple operation and the use of air-stable and commercially available zinc reagents.