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Synfacts 2008(10): 1102-1102  
DOI: 10.1055/s-2008-1078151
Organo- and Biocatalysis
© Georg Thieme Verlag Stuttgart ˙ New York

Asymmetric Synthesis of Tricyclic Benzopyrones

Contributor(s): Benjamin List, Kristina Zumbansen
H. Waldmann*, V. Khedkar, H. Dückert, M. Schürmann, I. M. Oppel, K. Kumar*
Max Planck Institut für molekulare Physiologie, Dortmund, Technische Universität Dortmund and Ruhr-Universität Bochum, Germany
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Publication History

Publication Date:
22 September 2008 (online)

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Significance

Waldmann, Kumar and co-workers report an organocatalyzed [4+2] annulation between electron-deficient heterodienes and acetylene derivatives to generate benzopyrones and dehydropyranes. The transformation tolerates several variations on the chromone ring and on the acetylene moieties. Also, acyclic oxadienes are employed in this reaction. Remarkably, an asymmetric version of this annulation reaction was developed by using the new cinchona alkaloid 1 as a catalyst.