First synthesis of Bacillus cereus Ch HF-PS cell wall trisaccharide repeating unit

The first total synthesis of Ch HF-PS, a cell wall trisaccharide repeating unit of B. cereus, is reported. The synthetic trisaccharide is appended with an aminopropyl linker at the reducing end to allow for conjugation to proteins and microarrays. The convergent synthesis involves transformation of d-mannose into an orthogonally protected rare AAT sugar building block, two consecutive α-stereoselective glycosylations, β-selective attachment of the linker by solvent participation, and amide bond formation, as key steps.