Asymmetric Synthesis of Selectively Protected Amino Sugars and Derivatives by a Direct Organocatalytic Mannich Reaction

Short and sweet: Starting from the commercially available precursors 1–3, selectively protected amino sugars and derivatives are obtained in one step and with high diastereo- and enantiomeric purity by means of a proline-catalyzed three-component Mannich reaction (see scheme, PMP=para-methoxyphenyl). This efficient organocatalytic procedure can be carried out smoothly on a multigram scale.