Regioselective alcoholysis of silybin A and B acetates with lipases

Large screening identified lipase AK to be capable of the selective deacetylation of pentaacetyl silybins A and B to yield 3,5,20,23-tetra-O-acetyl-silybins A and B, and 3,20,23-tri-O-acetyl-silybins A and B, respectively. Deacetylation occurred at phenolic OH groups, only. These new compounds prepared from the optically pure silybins can serve as new stereochemically pure synthons for selective silybin modifications.

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► Selective deacylation of optically pure silybins with lipases.
► Large screening of lipases (24) with a single hit, e.g. lipase AK.
► Detailed kinetic study allowing selective preparation of particular derivatives.