Sulfatase-catalyzed assembly of regioselectively O-sulfonated p-nitrophenyl α-d-gluco- and α-d-mannopyranosides

Abstract A chemoenzymic methodology is extended to the library synthesis of regioselectively O-sulfonated p NP d -gluco and d -mannopyranosides. The method involves the sequential reactions of chemical O-sulfonation and sulfatase-catalyzed O-desulfonation. p NP 2,6-di- O -sulfo-α- d -glucopyranoside and p NP 3,6-di- O -sulfo-α- d -mannopyranoside were obtained as sodium salts using chemical methods by way of dibutylstannylene acetals or tributylstannyl ethers. They were then applied to enzyme reactions using three molluscan enzymes (snail, limpet, and abalone). The sulfatase reactions cleaved a sulfate group at the secondary O-2 or O-3 position to yield the corresponding p NP 6- O -sulfo sugars. Neither p NP 6- O -sulfo-α- d -glucopyranoside nor 6- O -sulfo-α- d -mannopyranoside became the enzyme substrate. Evidently, the molluscan sulfatases have a tendency to cleave the secondary O -sulfo group with assistance from the 6- O -sulfo group.