The synthesis of a linear hexasaccharide, 2-(4-trifluoroacetamidophenyl)ethyl (β-d-galactopyranosyl)-(1->4)-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-(1- >3)-(β-d-galactopyranosyl)-(1->4)-(d-glycero-α-d-manno-heptopyranosyl)-(1- >6)-(β-d-glucopyranosyl)-(1->4)-l-glycero-α-d-manno-heptopyranoside, corresponding to a structure found in Haemophilus ducreyi LPS, is described. A Barbier reaction between benzyloxymethyl chloride and a properly protected 6-aldo-1-thio-mannopyranoside yielded both the d,d- and the l,d-heptopyranoside (2 and 3, ratio 2:3), which were separated and both used in the synthesis. p-Methoxybenzyl and chloroacetyl groups were employed as temporary protecting groups, selectively removed in the presence of the persistent benzyl, acetyl, benzoyl and isopropylidene groups by treatment with DDQ/H 2 O and hydrazine dithiocarbonate, respectively. Thioglycosides were utilised as donors throughout using either NIS/TfOH or DMTST as promoters. The introduction of the spacer into thioglycoside 5 was high-yielding (95%) but with low stereoselectivity (α:β 5:3). All other glycosylations are completely stereoselective. The target hexasaccharide is obtained via a 3+3 block approach with the yield in the final NIS/TfOH-promoted coupling between an N,N-diacetyl-trisaccharide thioglycosyl donor 20 and a 4''-OH trisaccharide acceptor 13 being 75%.