RSS-Feed abonnieren
DOI: 10.1055/s-2008-1032126
New Findings on the Cerium(IV) Ammonium Nitrate Catalyzed Povarov Reaction: Stereoselective Synthesis of 4-Alkoxy-2-aryl-1,2,3,4-tetrahydroquinoline Derivatives
Publikationsverlauf
Received
18 October 2007
Publikationsdatum:
06. März 2008 (online)
Abstract
Cerium(IV) ammonium nitrate catalyzes the three-component, imino Diels-Alder (Povarov) reaction between anilines, aromatic aldehydes, and acyclic vinyl ethers, giving cis-4-alkoxy-2-aryl-1,2,3,4-tetrahydroquinolines with almost complete diastereoselectivity. The corresponding reaction starting from cyclic vinyl ethers gave the two possible diastereomers, with the endo-compound as the major product. This stereochemical outcome is explained through a stepwise mechanism for the imino Diels-Alder reaction, and this mechanism was subsequently proved by trapping the putative oxonium intermediate in the presence of ethanol.
Key words
cycloadditions - multicomponent reactions - stereoselective synthesis - Lewis acids - quinolines