Synthesis of 3-O-arabinosylated (1 -> 6)-beta-D-galactan epitopes

Two tetrameric arabinogalactans, beta -D-galactopyranosyl-(1 -->6)-beta -D- galactopyranosyl-(1 -->6)-[alpha -L-arabinofuranosyl-(1 -->3)]-D-galactopyr anose (14) and alpha -L-arabinofuranosyl-(1 -->3)-beta -D-galactopyranosyl- (1 -->6)-beta -D-galactopyranosyl-(1 -->6)-D-galactopyranose (25), which ar e good candidates for CCRC-M7 epitope characterization, were synthesized ef ficiently using a convergent strategy. Migration of an acceptor acetyl grou p proved to be an obstacle to synthesis, but regioselective glycosylation o r 4-O-benzyl protection of the acceptor circumvented this problem allowing efficient synthesis of the 1 -->6 linked target compounds.