The use of enzymes to regioselectively deacylate sucrose esters

The deacylation activity of a range of hydrolytic enzymes on octa-O-acetyl sucrose has been investigated. From a total of 96 enzymes tested, 55 were active; 16 produced only heptaacetates, 12 produced hexaacetates and 27 could deacylate at 3 or more positions. Hydrolysis could only be achieved at 5 positions; the 3 primary positions plus the 4 and 4′ positions. The remaining 3 positions (2, 3 and 3′ were not hydrolysed. Only one enzyme tested was sufficiently active at all 5 positions to yield 2,3,3′tri-O-acetyl sucrose. Acyl migration occurred on the glucose ring of partially deacylated products, but this could be minimised by conducting reactions between pH 4 and 5. A range of specifically protected sucrose esters was obtained by using a combination of enzymes in sequence. No activity towards pentanoyl and butyryl esters of sucrose was detected. This finding was exploited by using butyryl groups as protecting groups in the enzymic deacylation of sucrose acetyl esters. These strategies can be used to synthesise specifically substituted sugars.