Journal of the American Chemical Society, Vol.128, No.11, 3638-3648, 2006
Total synthesis of phosphatidylinositol mannosides of Mycobacterium tuberculosis
The total synthesis of phosphatidylinositol mannosides (PIMs), a key class of antigenic glycolipids found on the cell wall of Mycobacterium tuberculosis, is described. The synthetic strategy relied on a [4 + 3] glycosylation of tetramannoside 1 and pseudotrisaccharide2, which allowed for convergent access to the glycan backbone of the phosphatidylinositol dimannoside (PIM2) and hexamannoside (PIM6). A short practical synthesis of tuberculostearic acid was achieved based on a copper-catalyzed cross-coupling reaction. Union of the glycan and lipid parts resulted in the first total synthesis of native PIM2 and PIM6.