Anionic Diels-Alder Chemistry of Cyclic Sodium Dien-1-olates Delivering Highly Stereoselective and Functionalized Polycyclic Adducts.

Anionic Diels-Alder chemistry of electron-deficient cross-conjugated vinylogous alkenones, providing highly stable sodium dienolate ion pairs as electron-rich dienes in the presence of a weak sodium base in THF, has been newly developed, leading to a single Diels-Alder adduct, in racemic form, in moderate to high yields (up to 97%, 37 examples).