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Synfacts 2006(1): 0073-0073  
DOI: 10.1055/s-2005-921708
Bioorganic Chemistry and Organocatalysis
© Georg Thieme Verlag Stuttgart · New York

Cysteine-Derived Organocatalyst for Enantioselective Michael Reactions

Contributor(s): Benjamin List, Sebastian Hoffmann
Y. Hayashi*, H. Gotoh, T. Tamura, H. Yamaguchi, R. Masui, M. Shoji
Tokyo University of Science, Japan
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Publication History

Publication Date:
16 December 2005 (online)

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Significance

An organocatalyzed enantioselective intramolecular Michael reaction is described. A cysteine-derived organocatalyst mediates the intramolecular addition of aldehydes to cyclic and acyclic α,β-unsaturated ketones with very good cis-diastereomeric ratios and up to 99% ee (8 examples, 10 mol% catalyst, 0 °C). The cis-disubstituted cyclopentanes can be selectively transformed to the thermodynamically more stable trans-isomers using DBU.