Proline-calixarene thiourea host-guest complex catalyzed enantioselective aldol reactions: from nonpolar solvents to the presence of water

Demircan E., EYMUR S., Demir A. S.

TETRAHEDRON-ASYMMETRY, vol.25, no.5, pp.443-448, 2014 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 25 Issue: 5
  • Publication Date: 2014
  • Doi Number: 10.1016/j.tetasy.2014.01.015
  • Journal Name: TETRAHEDRON-ASYMMETRY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.443-448
  • Middle East Technical University Affiliated: Yes

Abstract

A proline-calix[4]arene thiourea host-guest complex catalyzed intermolecular aldol reaction of aromatic aldehydes with cyclohexanone has been developed. The anti-configured products were obtained in good yields and with high enantioselectivities. The reaction is proposed to work via a modified Houk-List model, where the carboxylate part of the praline constitutes as a supramolecular system with the thiourea. The outcome of the study indicates the influence of the calix[4]arene thiourea on both the reactivity and selectivity in a non-polar reaction medium, even in the presence of water at moderate temperatures. (C) 2014 Elsevier Ltd. All rights reserved.