The First Total Synthesis of a Highly Branched Arabinofuranosyl Hexasaccharide Found at the Nonreducing Termini of Mycobacterial Arabinogalactan and Lipoarabinomannan

The first total synthesis of the arabinofuranosyl hexasaccharide present at the nonreducing termini of mycobacterial arabinogalactan and lipoarabinomannan is reported. The oligosaccharide was prepared as its methyl glycoside via a route that is both highly efficient and convergent. Addition of two β-d-arabinofuranosyl residues simultaneously in high yield and with excellent stereocontrol was the key step of the synthesis.