An efficient method for the stereoselective synthesis of N-substituted trihydroxypiperidine derivatives promoted by p-TsOH.

An effective and facile method for the synthesis of N- substituted trihydroxypiperidine derivatives is described. The Mannich-type reaction of protected 5- O -tosylate pentoses with amines and ketones in the presence of p -TsOH provides convenient access to the stereoselective synthesis of N -substituted iminosugar C -glycosides as potential glucosidase inhibitors in good to excellent yields. [ABSTRACT FROM AUTHOR]