Reductive opening of carbohydrate phenylsulfonylethylidene (PSE) acetals
Florence Chéry1, Elena Cabianca2, Arnaud Tatibouët1
1Université d'Orléans et CNRS, ICOA, UMR 7311, BP 6759, F-45067 Orléans, France.
Abstract:
The phenylsulfonylethylidene (PSE) acetal is a relatively new protecting group in carbohydrate chemistry. However, carbohydrate-derived phenylsulfonylethylidene (PSE) acetals show a different behavior in reductive desulfonylation than simple symmetrical acetals. Here we have investigated various SET-type reaction conditions in order to open PSE acetals regioselectively and to produce chiral ω-hydroxyethenyl ethers. Whereas sodium amalgam leads to a mixture of regioisomeric vinyl ethers besides the ethylidene acetal, samarium iodide is suited for regioselective ring opening. This is shown with seven different carbohydrate PSE acetals, both of the 1,3-dioxane and the 1,3-dioxolane type.
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