Synlett 2007(14): 2158-2167  
DOI: 10.1055/s-2007-985577
ACCOUNT
© Georg Thieme Verlag Stuttgart · New York

N-Heterocyclic Carbene-Copper(I) Complexes in Homogeneous Catalysis

Silvia Díez-González*, Steven P. Nolan*
Institute of Chemical Research of Catalonia (ICIQ), Av. Països Catalans 16, 43007 Tarragona, Spain
Fax: +34(977)920224; e-Mail: sdiez@iciq.es; e-Mail: snolan@iciq.es;
Further Information

Publication History

Received 10 March 2007
Publication Date:
13 August 2007 (online)

Abstract

N-Heterocyclic carbenes (NHCs) have become increasingly popular as ligands for transition metals, thanks to their ­remarkable successes in metathesis and cross-coupling areas. Important advances have also been achieved in organocopper chemistry. To date, the reported neutral N-heterocyclic carbene-copper(I) complexes have shown outstanding catalytic activity. In this account, we describe the application of such complexes in a ­variety of organic transformations.

  • 1 Introduction

  • 2 Copper-Hydride-Mediated Reactions

  • 2.1 Reduction of Carbonyl Compounds

  • 2.1.1 Activity and Scope

  • 2.1.2 Mechanistic Considerations

  • 2.2 Related Transformations

  • 3 Carbene Transfer Reactions

  • 3.1 Cyclopropanation and Insertion Reactions

  • 3.2 Olefination Reactions

  • 4 [3+2] Cycloaddition of Azides and Alkynes

  • 4.1 ‘Click Chemistry’

  • 4.2 Use of Internal Alkynes: Mechanistic Implications

  • 5 Miscellaneous Reactions

  • 6 Concluding Remarks

34

Formation of the homocoupling byproduct had occurred with the previously reported copper(I) complexes, see ref. 32.

43

As representative examples, the formation of the products given in Table [4] , entries 1 and 4, was not observed when the reaction was carried out in the presence of copper(I) chloride instead of [(IPr)CuCl].

59

[(IPr)CuCl] is now commercially available from Strem.