A set of 24 compounds (Figure ) was selected for preparative-scale synthesis, with the aim to have at least one example of each modified monosaccharide, and predominantly glycans with fluorination in multiple sugar residues. This aim required scaling up some reactions for which screening had shown relatively poor conversion, including those involving 3FGal and 6FGal. Following optimisation, comparable conversion efficiencies to the screening results (see SI) were achieved, and resulted in a library of 24 trisaccharides, which included all single fluoro/deoxy monosaccharides employed in the screen and examples with fluorination in two and three of the monosaccharide residues. NMR spectroscopic analysis of the scaled-up library confirmed that the trisaccharide products all possessed the correct Lewis x structure. Importantly, the increased chemical shift of fucose H-5 (4.77-4.88 ppm for Lewis x structures containing Fuc 4a, 3FFuc 4b, 4FFuc 4c; 5.01-5.53 ppm for Lewis x structures containing 6FFuc 4d) evidenced that all analogues adopted the well-defined 'closed conformation' when in aqueous medium, that is known to result from a non-conventional CH-O hydrogen bond between fucose H-5 and the ring oxygen of the galactosyl residue. Another consequence of this 'closed conformation' is the proximity of the fucose H-6 and galactose H-2 positions, which is believed to provide hydrophobic stabilisation to the closed conformation of Lewis x . Interestingly, NMR analysis of the 24 glycans also revealed a distinct increase, averaging 0.12 ppm, for the chemical shift of the galactose H-2 for those Lewis x analogues that contain a 6-fluorofucose residue, when compared to analogues with a normal fucosyl residue (see SI). It is postulated that Fuc F-6, interacts with Gal H-2, resulting in its higher chemical shift, and is taken as further evidence of the preservation of the Lewis x 3D-conformation in aqueous medium upon fluorination.