Cycloaddition reactions between 5-CMP 1 and various vinyl ethers and vinyl sulphides, catalysed by the Yb(OTf)(3)-Binol complex, afford bicyclic lactones 3 in moderate to excellent enantiomeric excesses.
Marko, I., & Evans, GR. (1994). Catalytic, Enantioselective, Inverse Electron-demand Diels-alder (iedda) Reactions of 3-carbomethoxy-2-pyrone (3-cmp). Tetrahedron Letters, 35(17), 2771-2774. https://doi.org/10.1016/S0040-4039(00)77029-8 (Original work published 1994)