TOTAL SYNTHESIS OF THE CARBOHYDRATE-PROTEIN LINKAGE REGION COMMON TO SEVERAL MAMMALIAN PROTEOGLYCANS

A stereocontrolled synthesis of beta-D-GlC pA-(1 --> 3)-beta-D-Gal p-( 1 --> 3)-beta-D-Gal p-(1 --> 4)-beta-D-Xyl p-(1 --> O)-L-Ser-Gly, the common glycopeptide sequence of the carbohydrate-protein linkage regio n of most mammalian proteoglycans, was achieved by use of O-[2-(trimet hylsilyl)ethyl 3,4-tri-O-benzoyl-beta-D-glucopyranosyluronate]-(1 --> O-(2,4,6-tri-O-benzoyl-beta-D-galactopyranosyl)-(1 --> O-(2,4,6-tri-O- benzoyl-beta-D-galactopyranosyl)-(1 --> 4)-2,3-di-O-benzoyl-alpha,beta -D-xylopyranosyl trichloroacetimidate as the key intermediate. Condens ation of this glycosyl donor with suitably protected L-Seryl-glycine d ipeptide segments, and peptide chain elongation, allowed the construct ion in high yield of complex structures of this linkage region.