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Synfacts 2007(4): 0432-0432  
DOI: 10.1055/s-2007-968354
Organo- and Biocatalysis
© Georg Thieme Verlag Stuttgart · New York

Brønsted Acid Catalyzed Asymmetric Nazarov Cyclization

Contributor(s): Benjamin List, Subhas Chandra Pan
M. Rueping*, W. Ieawsuwan, A. P. Antonchick, B. J. Nachtsheim
Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany
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Publication History

Publication Date:
23 March 2007 (online)

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Significance

The Nazarov cyclization is an important electrocyclic reaction for the synthesis of five-membered rings (see review below). Here the authors report an organocatalytic asymmetric Nazarov cyclization using N-triflyl phosphoramide 1 as catalyst. With 2 mol% of catalyst 1 moderate to good diastereoselectivities (1.5:1 to 9.3:1) and high enantioselectivities (er = 93:7 to 99:1) are obtained for different alkyl- and aryl-substituted dienones.