C-alkoxycarbonyl nitrones: Building blocks for the synthesis of butenolides, lactams and modified nucleosides

Elaboration of isoxazolidines derived from the 1,3-dipolar cycloaddition of C-alkoxycarbonyl nitrones to suitably substituted alkenes leads to the development of new synthetic methodologies for the preparation of a wide range of natural products and derivatives including lactones, lactams and complex nucleosides. The insertion of a chiral centre in position α, with respect to nitrone functionality, or the presence of a chiral auxiliary at the nitrogen atom have allowed the enantioselective synthesis of the same compounds.