Efficient synthesis of 3-methylene-2-pyrrolidinone and highly exoselective diels-alder addition to cyclopentadiene

Article abstract of DOI:10.1016/S0040-4039(98)02542-8

A new efficient synthesis of 3-methylene 2-pyrrolidinone 1 involving ylide-lactame 6 is reported. Diels-Alder cycloadditions of 1 to cyclopentadiene exhibited very high exoselectvities, regardless Of the experimental conditions. These results confirm the generality of exoselectivity for conformationally restricted s-cis dienophiles and indicate that the dienophile functionality and dipole moment have little influence on its magnitude.