One‐Pot Synthesis of Semisaturated Fused Polycyclic Iminosugars by a Diels‐Alder Reaction

Abstract: A series of semi‐saturated fused polycyclic iminosugars were synthesized by one‐pot stereoselective three‐component reactions of D‐ribose tosylate, aniline and cycloenones under heating conditions. The N‐aryl enamine derived from an iminium ion is the key intermediate for the reaction. In this way, various novel complex fused iminosugars were obtained through a normal Diels‐Alder mechanism at 80 °C. This strategy will enable the preparation of bioactive iminosugar analogues with structural diversity.