Regioselective protection sucrose

Sucrose is probably the cheapest starting material in the world, available in vast quantities from sugar canes and beets. Nonetheless, its regioselective protection is a real challenge. 

The preparation of well defined sucrose polyurethanes has been investigated in studies with partially protected sucrose esters [54]. Regioselectivity observations on the carbamoylation of sucrose in DMF showed in the case of alkylisocyanates a clear preference for the reaction position at the 2-OH in the glucose part. When phenylisocyanate is used the most favored reaction position is the 6-OH-group followed by the 2-OH-group [55, 56]. Similar regioselectivities could also be found for the reaction of the respective diisocyanates with sucrose [56]. 

Regioselectively protected cytidine derivatives have been prepared from the peracetylated nucleoside using lipase and esterase reactions. There have been reports on the use of bacterial proteases for the selective acylation of sucrose to produce a variety of different acyl and acrylate esters. 8-Aminooctyl 5-5-coniferyl-5-thio-a-L-arabinofuranoside(27) attached to sepharose proved to be a selective affinity ligand for feruloyl esterase A. niger ... 

Regioselective silylation of sucrose afforded the 6 -protected derivative, which was fully benzylated and then deprotected at the 6 -position, and further... 

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