Pure Appl. Chem., 2008, Vol. 80, No. 5, pp. 1063-1069
doi:10.1351/pac200880051063
Golden opportunities in catalysis*
Norbert Krause, Volker Belting, Carl Deutsch, Jörg Erdsack, Hong-Tao Fan, Birgit Gockel, Anja Hoffmann-Röder, Nobuyoshi Morita, and Frank Volz
Organic Chemistry II, Dortmund University of Technology, Otto-Hahn-Strasse 6, D-44227 Dortmund, Germany
Abstract:
The gold-catalyzed endo-cycloisomerization of allenes bearing nucleophilic substituents in the α- or β-position opens up a versatile access to various five- and six-membered heterocycles. Key features of these transformations are the high reactivity of the allene in the presence of Lewis-acidic, carbophilic gold(I) or gold(III) catalysts, and the chirality transfer from the allenic axis of chirality to the new stereogenic center in the cyclization product. Recent contributions of our group include the optimization of chirality transfer by using σ-donor ligands to gold, and applications in the total synthesis of natural products, e.g., of the β-carboline alkaloids (-)-isocyclocapitelline and (-)-isochrysotricine.
Keywords: allenes; chirality transfer; cycloisomerization; gold catalysis; heterocycles.
*Paper based on a presentation at the 14th International Symposium on Organometallic Chemistry Directed Towards Organic Synthesis (OMCOS-14), 2-6 August 2007, Nara, Japan. Other presentations are published in this issue, pp. 807-1194.
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