IODONIUM ION-ASSISTED SYNTHESIS OF TETRAMERIC FRAGMENTS CORRESPONDINGTO THE CELL-WALL PHENOLIC GLYCOLIPIDS OF MYCOBACTERIUM-KANSASII SEROVAR-II AND SEROVAR-IV

The spacer-containing tetramers 3 and 4, derivatives of the phenolic g lycolipids of Mycobacterium kansasii serovars II and IV were prepared by iodonium ion-mediated mannosylation of trimeric acceptor 4-[2-(benz yloxycarbonylamino)ethyl]phenyl -alpha-L-rhamnopyranosyl]-alpha-L-rham nopyranoside (2) with ethyl 1-thio-D-mannopyranoside donors 7, 13, and 24. In addition, the glycosylating properties of donors 7, 13, 24, 29 -31, each containing a different protective group at position 2, were examined by executing condensations with model acceptor 18(L) and its enantiomer 18(D).