Double catalytic activation with chiral Lewis acid and amine catalysts

An effective enantio selective synthetic method based on a new concept of double catalytic activation has been developed, in which both electrophile and nucleophile precursors are activated by use of catalytic amounts of chiral Lewis acid and amine base, respectively. This method has been successfully applied to enantioselective thiol conjugate additions, as well as to Michael reactions of malononitrile, nitromethane, and cyclic 1,3-dicarbonyl compounds in the presence of DBFOX/Ph - nickel(II) aqua complexes with amines. This new method should be a powerful tool, especially when single catalytic activation of either nucleophiles or electrophiles is not sufficient to induce bond formation. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)