Regioselective Deacetylation of Peracetylated Deoxy--glycopyranosides by Boron Trichloride (BCl).

A general approach for regioselective deacetylation at sugar 3-OH of peracetylated 6-deoxy--glucopyranosides mediated by BCl was developed. The approach could be extended to other sugar-derived 6-deoxy--glycopyranosides, such as those derived from mannose, galactose, and rhamnose, with deacetylation occurring at varied sugar hydroxyl groups, and further extended to 4-deoxy--glucopyranosides with deacetylation occurring at sugar 3-OH. The approach would enable access to synthetically challenging carbohydrate derivatives.