Selective biocatalytic deacylation studies on furanose triesters: a novel and efficient approach towards bicyclonucleosides.

Lipozyme TL IM catalyses the deacylation of 4-C-acyloxymethyl-3,5-di-O-acyl-1,2-O-(1-methylethylidene)-beta-L-threo-pentofuranose to form 3,5-di-O-acyl-4-C-hydroxymethyl-1,2-O-(1-methylethylidene)-alpha-D-xylo-pentofuranose in a highly selective and efficient manner. The rate of lipase-catalyzed deacylation of tributanoyl furanose is 2.3 times faster than the rate of deacylation of the triacetyl furanose derivative. In order to confirm the structure of the lipase-catalyzed deacylated product, it was converted to a bicyclic sugar derivative, which can be used for the synthesis of bicyclic nucleosides of importance in the development of novel antisense and antigene oligonucleotides. Further, it has been established that the monohydroxy product of the lipase-catalyzed reaction is the result of selective deacylation of the 4-C-acyloxymethyl function in the substrate and not of any acyl migration process.