A stereoselective and flexible synthesis to access both enantiomers of N-acetylgalactosamine and peracetylated N-acetylidosamine

• Bettina Riedl and
• Walther Schmid

Beilstein J. Org. Chem. 2018, 14, 856–860, doi:10.3762/bjoc.14.71

• -catalyzed, stereo- and regioselective epoxide opening and subsequent nucleophilic substitution of an azide functionality. This approach enables the synthesis of the naturally D- and unnaturally L-configured GalNAc, as well as both enantiomers of the largely unknown N-acetylidosamine (IdoNAc). Keywords

• : asymmetric synthesis; carbohydrates; N-acetylgalactosamine; N-acetylidosamine; Introduction N-Acetylgalactosamine (GalNAc, Figure 1) and N-acetylidosamine (IdoNAc) belong to the group of 2-amino-2-deoxysugars, which can be found in a wide range of organisms as building blocks of, e.g., glycosaminoglycans

• , this approach was additionally adapted for the synthesis of peracetylated D-N-acetylidosamine 2c. Therefore, the epoxidation of 4a was performed with D-DET instead of L-DET, resulting in D-epoxythreitol 5c (Scheme 4). Performing the presented, optimized reaction sequence resulted in the formation of