A novel intramolecular Diels-Alder reaction involving the addition of an α, β-unsaturated aldehyde to an electron-deficient, dienophilic partner has been exploited as the key step in the development of a general entry to the heteroyohimboid and corynantheioid alkaloids. Thus, the thermal cyclization of the nitrogen-linked triene 11, which is readily available in eight steps from propargyl alcohol, proceeded smoothly to afford the cis-cycloadduct 20 in ...
