TOTAL SYNTHESIS AND PROOF OF STRUCTURE OF A HUMAN BREAST-TUMOR (GLOBO-H) ANTIGEN

The total synthesis of the Hakomori MBr1 antigen, heavily expressed on human breast tumors, is related. The construction involved the assemb ly of four glycals: (17 (twice), 18, 20, and 26) and an L-fucose deriv ative, 34. The sensitivity of the stereochemistry of sulfonamido galac tosylation by a terminal galactose ring as a function of the state of protection status of its C-4 alcohol was exploited in a key step. (See the formation of compound 51.) The synthesis served to confirm the Ha komori assignment of structure, and paves the way for immunoconjugatio n.