Convenient synthetic approach towards regioselectively sulfated sugars using limpet and abalone sulfatase-catalyzed desulfation

3,6-Disulfated p-nitrophenyl β-D-galactopyranoside 3 and 3′,6′-disulfated p-nitrophenyl β-lactoside 7, which were regioselectively obtained via organotin methodology, were subjected to enzymatic desulfation: limpet and abalone sulfatases (EC 3.1.6.1) hydrolyzed regioselectively the 3- and 3′-sulfate moieties of 3 and 7 to afford 6-monosulfated galactopyranoside 4 and 6′-monosulfated lactoside 8, respectively.