Stereoselective synthesis of seven-membered lactams and lactones on a carbohydrate scaffold using ring-closing metathesis

We present here the application of Grubbs’ 2nd generation catalyst for the ring-closing metathesis of electron-deficient α,β-unsaturated amides and esters leading to the synthesis of enantiopure azepinone and oxepinone derivatives on a carbohydrate glycoside scaffold. The relative stereochemistries of the compounds obtained were corroborated by X-ray crystallography, 1H NMR or deduced based on previously reported results. These compounds are designed as precursors of new polyhydroxylated heteroannulated sugars with potential biological activity.