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Synlett 2010(1): 128-130  
DOI: 10.1055/s-0029-1218547
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

The Domino Oxa-Michael-Aldol-Reaction Reinvestigated: A New P-Based Organocatalyst for Xanthenone Scaffolds

Sefer Aya, Emilie M. C. Gérarda, Min Shi*b, Stefan Bräse*a
a Institute for Organic Chemistry, University of Karlsruhe (TH) and Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
Fax: +49(721)608858; e-Mail: braese@kit.edu;
b State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry (SIOC), Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, P. R. of China
Fax: +86(21)64166128; e-Mail: Mshi@mail.sioc.ac.cn.;
Further Information

Publication History

Received 8 September 2009
Publication Date:
09 December 2009 (online)

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Abstract

The oxa-Michael-aldol condensation reaction offers a fast access to xanthenone scaffolds, which are an important structural motif in natural products. This reaction was investigated and a new organocatalyst based on phosphine was discovered (PhPMe2). After optimization of the reaction conditions, the Michael donors and acceptors were screened to determine the scope and limitations of this reaction. Furthermore, important observations were made, allowing the formulation of a surprising reaction pathway for this catalyst system.

Key words

organocatalyst - domino oxa-Michael-aldol - phosphine - heterocycles - xanthenones

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