Ugi three-component coupling strategy for the synthesis of bridged bicyclic iminosugars

A catalyst-free approach has been accomplished for the synthesis of bridged bicyclic iminosugars through a Ugi 3CC reaction of tosylribose, primary amine and isonitrile under mild conditions. This is the first example of the construction of bridged bicyclic iminosugar frameworks by a simple three-component four-center Ugi-type coupling reaction. This newly developed protocol paves the way to building bridged bicyclic scaffolds, which are key precursors to six-membered iminosugars.