Efficient Entry to Amino Sugars and Derivatives via Asymmetric Organo­catalytic Mannich Reactions

Abstract

An efficient biomimetic C₃+C_n entry to amino sugars and derivatives via a direct asymmetric organocatalytic Mannich methodology employing 2,2-dimethyl-1,3-dioxan-5-one as a dihydroxyacetone phosphate equivalent and N-PMP or N-Boc protected imines has been developed. The Mannich bases were obtained in high diastereo- and enantiomeric excesses (78% to >99% de, 81-98% ee) and were further elaborated using diastereoselective reduction protocols, as well as via diastereoselective direct reductive amination­ reactions.