Synthesis of the NAG–NAM disaccharide via a versatile intermediate

• A simple synthesis of the NAG–NAM disaccharide, crucial for the preparation of the bacterial peptidoglycan was achieved.
• The strategy relies on the preparation of a versatile intermediate that can be used for the synthesis of unnatural glycopeptides.
• The synthetic strategy requires a minimal use of protecting group manipulation.

A simple strategy for the synthesis of a β-GlcNAc-(1→4)-MurNAc (NAG–NAM) moiety, crucial for the preparation of synthetic components of a bacterial peptidoglycan, was achieved. This strategy relies on the use of three O-protecting groups, 4,6-O-benzilidene acetal, benzyl, and acetyl group, which allows further regioselective manipulation at O-3, O-4 positions, and on the insertion of the peptide chain at the lactate moiety in an advanced and versatile intermediate. Overall, a simple route to achieve the biological relevant NAG–NAM is presented, which may serve as a conceptual framework in the designing of synthetic strategies of different natural and non-natural polysaccharides.

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