Efficient construction of cyclopenta[b]quinoline core of isoschizozygane alkaloids via intramolecular formal hetero-Diels-Alder reaction

[GRAPHICS] Acid-catalyzed condensation of aromatic amines with delta,epsilon-unsaturated aldehydes, followed by intramolecular formal hetero Diels-Alder reaction, is described as a potential route to the cyclopenta[b]quinoline substructure of isoschizozygane alkaloids. Reactions are highly diastereoselective and produce adducts with up to four contiguous stereocenters.