Influencing the regioselectivity of lipase-catalyzed hydrolysis with [bmim]PF6

An easy preparation of mono-deprotected thioglucopyranosides via a selective Candica cylindracea lipase-catalyzed hydrolysis of a commercially available peracetylated precursor is described. Especially, ethyl 2,3,4-tri-O-acetyl-1-thio-β-d-glucopyranoside and ethyl 2,3,6-tri-O-acetyl-1-thio-β-d-glucopyranoside were obtained in 100% and 54% isolated yields, respectively. The influence of the ratio of [bmim]PF6/buffer toward the regioselectivity of the deacetylation step and the acyl migration is discussed.