The synthesis of spacer-containing fragments of the capsular poly-saccharide of H.influenzas, comprising two and three repeating units (9aand9b, respectively), is presented. Ribosylribitol building blocks1and2were coupled with bis [1-benzotriazolyl]-2-chlorophenyl phosphate (3) to give the phosphotriester derivative5a(72%), which was selectively deprotected at O-5 of the terminal ribitol residue (cleavage of the trans-1-propenyl ether) to afford compound6a(82%). Repeated coupling of building block2with6a(chain elongation), followed by propenyl- cleavage, gave analogue6b. Both derivatives6aand6bwere coupled with spacer7(chain termination). The fully protected fragments8a(84%) and8b(49%, starting from6a) were thus obtained. Complete deprotection of8aand8bwas achieved in three steps. After purification and cation-exchange,9aand9bwere obtained in 41 and 68% yields, respectively. The structural integrity of the largest fragment (9b) was confirmed by FAB MS and various NMR spectroscopic techniques.