An Efficient Route toward 2-Amino-β-D-galacto and -glucopyranosides via Stereoselective Michael-Type Addition of 2-Nitroglycals

摘要

Under the catalysis of DMAP or PPY in CH_2Cl_2, the Michael-type addition of nucleophiles to 2-nitrogalactal or 2-nitroglucal leads in excellent yields and stereoselectivity to the corresponding β-galacto- or -glucopyranosides, which are ready precursors to the biologically significant β-Dgalactosamine and -glucosamine units.