A reliable method is disclosed to introduce a fused methylene tetrahydrofuran ring into carbohydrates. The resulting bicyclic saccharides can be used as scaffolds in medicinal chemistry and drug design. In addition, the enol ether functionality serves as a handle that enables modification in biological systems via photoclick chemistry. The approach is based on the regioselective oxidation of the C-3 hydroxy group in gluco-configured pyranosides, followed by stereoselective indium-mediated allylation. The ring formation is induced by an iodocyclization reaction with a neighboring hydroxy group. Subsequent dehydrohalogenation affords the desired methylene-tetrahydrofuran-containing carbohydrates.
- enol ether
- site selectivity