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Synfacts 2006(8): 0845-0845  
DOI: 10.1055/s-2006-942022
Organo- and Biocatalysis
© Georg Thieme Verlag Stuttgart · New York

Diastereoselective Direct Aldol Reaction Catalyzed by Proline

Contributor(s): Benjamin List, Daniela Kampen
B. Alcaide*, P. Almendros*, A. Luna, M. R. Torres
Universidad Complutense de Madrid and Instituto de Química Orgánica General, CSIC, Madrid, Spain
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Publication History

Publication Date:
21 July 2006 (online)

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Significance

An organocatalytic diastereoselective direct aldol reaction has been described. Enantiopure 4-oxoazetidine-2-carbaldehydes 1 react with ketones 2 in the presence of l-proline (10 mol%) to provide aldols of type 3 in excellent yields and diastereoselectivities. In contrast to this matched case, the use of d-proline as catalyst provides the opposite diastereoisomer 4 in lower diastereoselectivities in a mismatched case. Possible transition states to explain the observed stereochemistry are proposed.