Diversity‐Oriented Synthesis and Biological Evaluation of Iminosugars from Unprotected 2‐Deoxy‐<scp>d</scp>‐ribose

Abstract

An exceptionally short synthesis of novel indolizidine‐, quinolizidine‐, and piperidine‐based iminosugars from unprotected 2‐deoxy‐ d ‐ribose by intramolecular 1,3‐dipolar cycloaddition of sugar‐derived N ‐(3‐alkenyl)nitrones has been accomplished. The use of the 2‐deoxy carbohydrate also enabled us to confirm the previously proposed mechanism for the alteration of the stereochemical course of the intramolecular 1,3‐dipolar cycloaddition observed for an unprotected sugar‐derived nitrone. Biological assays of the six new iminosugars revealed a slight inhibition activity of the indolizidine derivative 7a , whereas, interestingly, the two quinolizidine iminosugars 5a and 5b appeared to be weak glycosidase activators.