Lewis Acid Catalyzed Intermolecular Olefin Hydroamination: Scope, Limitation, and Mechanism

Intermolecular olefin hydroamination was studied by various Lewis acids. The results of ZrCl(4), FeCl(3), BiCl(3), and AlCl(3) catalyzed reactions of norbornene with aromatic amines were compared, and BiCl(3) was found to be the most effective catalyst to give high yields for various amines, whereas ZrCl(4) could promote the reactions at relatively low temperatures. The FeCl(3) catalyzed reactions were the most chemoselective and excellent yields could be achieved for certain amines by using AlCl(3). A carbocation mechanism was proposed, and the controllable syntheses of allylamine and tetrahydroquinoline from isoprene and 2,5-dichloroaniline were achieved by application of this mechanism. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).