Synlett 2017; 28(06): 640-653
DOI: 10.1055/s-0036-1588693
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© Georg Thieme Verlag Stuttgart · New York

NHC–AuCl/Selectfluor: An Efficient Catalytic System for π-Bond Activation

Kai Chen
Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, P. R. of China   Email: zhusf@scut.edu.cn
,
Shifa Zhu*
Key Laboratory of Functional Molecular Engineering of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, P. R. of China   Email: zhusf@scut.edu.cn
› Author Affiliations
Further Information

Publication History

Received: 14 December 2016

Accepted after revision: 06 January 2017

Publication Date:
02 February 2017 (online)


Abstract

Gold complexes have emerged as one of the most efficient catalysts for electrophilic activation of π bonds toward a variety of nu­cleophiles. N-Heterocyclic carbenes (NHCs), commonly described as excellent σ donors, are becoming increasingly employed in gold catalysis. Selectfluor as external oxidant is able to oxidize Au(I) to Au(III) species, which plays a unique role in the NHC–AuCl/Selectfluor combination. This account describes our recent discovery and development of this efficient catalytic system, NHC–AuCl/Selectfluor, which can be used in cross-coupling reactions of alkenes and arylboronic acids, tandem Diels–Alder/Diels–Alder (DA/DA) reactions of enynals/enynones with alkenes, and carbene-transfer reactions. We believe this account not only should help the understanding of the Au(I)/Selectfluor catalytic system but also promote the development and application of other combinations of low-oxidation-state transition metal/Selectfluor or transition metal/oxidant as catalysts in organic synthesis.

1 Introduction

2 Discovery of the NHC–AuCl/Selectfluor Catalytic System

3 Development of NHC–AuCl/Selectfluor in Tandem DA/DA Reactions of Enynals/Enynones with Alkenes

3.1 Two-Component Three-Molecule Tandem DA/DA Reactions

3.2 Three-Component Three-Molecule Tandem DA/DA Reactions

3.3 Bioinspired Intramolecular DA/DA Reactions

3.4 Investigations of Reaction Mechanism

4. Development of NHC–AuCl/Selectfluor in Carbene-Transfer Reactions

5. Summary and Outlook