Candida antarcticaB lipase-catalysed alcoholysis of peracetylated alkyl D-ribofuranosides

Candida antarctica B lipase (CAL-B) catalysed alcoholysis of a series of peracetylated alkyl α, β-D-ribofuranosides was assayed. Methyl and ethyl 2,3-di-O-acetyl-α, β-D-ribofuranosides enriched in the α-anomer were regioselectively prepared through this enzymatic deacetylation in 33% and 43% yield, respectively, the latter being a new compound. Isopropyl 2,3,5-tri-O-acetyl-β-D-ribofuranoside gave the new isopropyl 2,3-di-O-acetyl-β-D-ribofuranoside in 24% yield. The anomeric substituent affects the regioselectivity of the reaction, since n-propyl and n-butyl α, β-D-ribofuranosides reacted without selectivity.