Synthesis of γ-hydroxyalkyl substituted piperidine iminosugars from D-glucose

(Chemical Equation Presented) D-Glucose was converted to synthetic equivalent of meso-pentodialdose, namely 3-C-(1′-aminoethyl)-α-D- ribo-pentodialdo-1,4-furanose 10 that gives an easy access to manipulate the aldehyde functionalities on either sides to get enantiomeric pair of 3. Thus, reduction of C5-aldehyde followed by hydrolysis of 1,2-acetonide functionality and reductive aminocyclization with C1-aldehyde afforded γ-1,2- dihydroxyethyl piperidine iminosugar 3. On the other hand, first reductive aminocyclization with C5-aldehyde gave piperidine ring skeleton 12 that on removal of 1,2-acetonide and reduction of C1-aldehyde gave ent-3 while chopping of C1-aldehyde in 12 and reduction afforded γ-hydroxymethyl piperidine iminosugar 4.