First Stereocontrolled Reduction of Isoxazoline by Hydrogenolysis: A New Route to Iminosugars via Cyclic Sulfates
Résumé
The synthesis of four new trihydroxylated piperidines, considered as analogues of 1-deoxynojirimycin (DNJ) and 1-deoxymannojirimycin (DMJ), was achieved using cyclic sulfates substituted isoxazoline derivatives. The key step is the one-pot reduction of an isoxazoline to an amine which undergoes intramolecular attack on the sulfate ester with high stereoselectivity and regioselectivity. The isoxazoline precursors were obtained by the 1,3-dipolar cycloaddition reaction between 2,2-dimethyl-4-vinyl-1,3-dioxolane and 1-benzyloxy-2-nitroethane.