Patent ID: 7582737

Claim:
An orthogonally protected disaccharide building block of formula (I): wherein L is a leaving group O-trichloroacetimidyl, P 1 , P 2 , P 3 and P 4 are hydroxyl protecting groups, and of them P 1 is an ester-type protecting group selected from the group consisting of acyl and benzoyl (Bz), P 2 is selected from the group consisting of levulinyl (Lev), acyl and acetyl (Ac), P 3 is benzyl (Bn) or substituted benzyl, and P 4 is selected from the group consisting of naphthylmethyl (NAP), substituted naphthylmethyl, p-methoxybenzyl and substituted p-methoxybenzyl, and wherein the wavy line represents an α- or β-linkage.