Synlett 2011(10): 1357-1369  
DOI: 10.1055/s-0030-1260582
ACCOUNT
© Georg Thieme Verlag Stuttgart ˙ New York

Metal-Stabilized o-Quinone Methides, Thioquinones, and Selenoquinones: Trapping Important Reactive Intermediates and Beyond

Hani Amouri*
Institut Parisien de Chimie Moléculaire, UMR CNRS 7201 Université Pierre et Marie Curie Paris-6, 4 place Jussieu, case 42, 75252 Paris Cedex 05, France
Fax: +33(1)44273841; e-Mail: hani.amouri@upmc.fr;
Further Information

Publication History

Received 18 February 2011
Publication Date:
26 May 2011 (online)

Abstract

Quinone methides (quinomethanes) act as important intermediates in organic syntheses, as well as in chemical and biological processes. However, examples of such isolated species are scarce owing to their high reactivity. Other important reactive intermediates are thio- and selenoquinones. However, unlike quinones, they are highly unstable and consequently do not exist in nature, hence their chemical and biological properties remain unknown. In this account, we describe the first isolation of the above important reactive intermediates, by π-coordination to a (pentamethylcyclopentadienyl)iridium (Cp*Ir) moiety, and their X-ray molecular structures. Further, the reactivity of such trapped intermediates is reported. For instance, the metalated o-quinone methide underwent an unusual cycloaddition reaction compared with the free o-quinone methide, while the metalated thioquinones were successfully used as organometallic linkers (OM-linkers) to construct luminescent coordination assemblies. The anticancer activity of the selenoquinone metalated complex was studied, together with related oxygen and sulfur analogues, and remarkably it was shown to be the only cytotoxic compound with a comparable activity to cisplatin.

1 Introduction

2 Quinone Methides

2.1 First Isolation of Metal-Stabilized o-Quinone Methides

2.1.1 Synthesis and Structural Characterization

2.1.2 Reactivity towards Electrophiles and Carbon-Carbon Bond Formation

3 Thioquinones

3.1 First Isolation as Metal Complexes

3.1.1 Synthesis and Structural Characterization

3.1.2 Reactivity as Organometallic Linkers

4 Selenoquinones

4.1 Trapping Selenoquinones as Metal Complexes

4.1.1 Synthesis and Structural Characterization

4.1.2 Biological Properties

5 Concluding Remarks and Future Outlook