A highly expeditious synthesis of a bicyclic iminosugar using the novel key step of [NMM]+[HSO4]− promoted conjugate addition and Mitsunobu reaction

Abstract

A simple and highly facile protocol has been developed for the stereoselective synthesis of 1-deoxy-norcastanospermine from readily available D-glucose. N-Methylmorpholinium hydrogen sulphate was seen for the first time as a suitable catalyst for the facile conjugate addition of an amine to a glycosyl olefinic ester. Furthermore, the key step of this strategy is the internal reductive amination of glycosyl azetidine, obtained from glycosyl β-amino alcohol under Mitsunobu reaction conditions.