Dihydroxypyrrolidines C-linked to galactose. Total synthesis of a specific inhibitor of α-mannosidases

New disaccharide mimics connecting 4-amino-4-deoxyerythrofuranose at C(1) to position C(3) of galactose through a CH(OH) link have been prepared as racemates and tested toward 25 commercially available glycohydrolases. One of them (2) is a moderate but specific (43% of inhibition at 1mM) inhibitor of jack bean α-mannosidase.