Synthesis 2010(1): 1-26  
DOI: 10.1055/s-0029-1217130
REVIEW
© Georg Thieme Verlag Stuttgart ˙ New York

Enantioselective Organocatalytic Diels-Alder Reactions

Pedro Merino*a, Eugenia Marqués-Lópezb, Tomás Tejeroa, Raquel P. Herrera*a,c
a Laboratorio de Síntesis Asimétrica, Departamento de Química Orgánica, Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza, CSIC, 50009 Zaragoza, Aragón, Spain
Fax: +34(976)762075; e-Mail: pmerino@unizar.es; e-Mail: raquelph@unizar.es;
b Technische Universität Dortmund, Organische Chemie, Otto-Hahn-Str. 6, 44227 Dortmund, Germany
c Fundación ARAI+D, Gobierno de Aragón, 50009 Zaragoza, Spain
Further Information

Publication History

Received 1 September 2009
Publication Date:
20 November 2009 (online)

Abstract

Enantioselective organocatalytic asymmetric Diels-Alder­ reactions provide a facile and efficient route to optically active functionalized cyclohexenes, which can be further transformed into a variety of important organic compounds. A variety of small organic molecules such as prolines, imidazolidinones, chiral Brønsted­ acids, guanidines, carbenes and Cinchona alkaloids can be used as different catalyst systems to induce enantioselectivity in the reaction. This review provides an overview of the history of the asymmetric organocatalyzed Diels-Alder reaction.

1 Introduction

2 Chiral-Base-Catalyzed Diels-Alder Reactions

2.1 Chiral Secondary Amines

2.2 Chiral Primary Amines

2.3 Cinchona Alkaloids

2.4 Heterocyclic Carbenes

2.6 Chiral Guanidines

3 Hydrogen-Bond-Catalyzed Diels-Alder Reactions

4 Concluding Remarks

18

A dedicated chapter to cycloaddition reactions with eleven references concerning organocatalytic Diels-Alder reactions can be found in the book edited by Berkessel and Gröger (see ref. 17a).

70

For a review, see ref. 21c.

118

The nine-membered cyclic structure was observed as one of the energy minima of the complex derived from 120 (without pyridine) and 121 by quantum chemical calculations (PM3, Spartan ’02, Wavefunction, Inc.). The authors supposed pyridine would not participate in the transition state but may stabilize Brassard’s diene in the reaction.