Synthesis 2005(14): 2407-2413  
DOI: 10.1055/s-2005-870026
PAPER
© Georg Thieme Verlag Stuttgart · New York

4-Substituted Prolyl Sulfonamides as Enantioselective Organocatalysts for Aldol Reactions

Evagelos Bellis, Konstantina Vasilatou, George Kokotos*
Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece
Fax: +30(210)7274761; e-Mail: gkokotos@cc.uoa.gr;
Further Information

Publication History

Received 17 January 2005
Publication Date:
14 July 2005 (eFirst)

Abstract

A series of prolyl and 4-substituted prolyl sulfonamides were prepared and were evaluated as organocatalysts of asymmetric aldol reaction. Using prolyl methanesulfonamide, 4-benzyloxy-prolyl methanesulfonamide and toluenesulfonamide and 4-hydroxy­prolyl toluenesulfonamide the aldol product was obtained in much higher enantiomeric excess (ee) in comparison to that observed using proline itself. In addition, these new catalysts may be used in lower sub-stoichiometric amounts than proline, because of their improved solubility in organic solvents.

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Presented in part at the 1st Hellenic Symposium on Organic Synthesis; Athens, 4-6 November, 2004; Abstracts p. 41.