Iminosugar C-Nitromethyl Glycoside: Stereoselective Synthesis of Isoxazoline and Isoxazole-Fused Bicyclic Iminosugars

摘要

A simple and efficient method for the stereoselective synthesis of isoxazoline/isoxazole-fused iminosugar derivatives has been developed using intramolecular nitrile oxide cycloaddition (INOC) as a key step. Iminosugar C -nitromethyl glycosides, derived from simple carbohydrates, served as excellent nitrile oxide precursors in 1,3-dipolar cycloaddition reactions. N -Alkenyl iminosugar C -nitromethyl glycosides afforded novel isoxazoline-fused indolizidine-, pyrrolizidine-, and quinolizidine-based iminosugars in excellent yields with a high degree of stereoselectivity, whereas N -alkynyl iminosugar C -nitromethyl glycosides furnished the corresponding isoxazole containing tricyclic iminosugars in very good yields.