Gold Carbenoids: Lessons Learnt from a Transmetalation Approach1. (27th November 2013)

• Record Type: Journal Article
• Authors: Seidel, Günter; Gabor, Barbara; Goddard, Richard; Heggen, Berit; Thiel, Walter; Fürstner, Alois
• Is Part Of: Angewandte Chemie. Volume 126:Number 3(2014)
• Page Start: 898
• Page End: 901
• Publication Date: 2013-11-27
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201308842
• Languages: English
• ISSNs: 0044-8249

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Carbophilic catalysts that are based on Au^I allow a host of different nucleophiles to be added across various π systems.<xref ref-type="link" rid="bib1">1</xref>–<xref ref-type="link" rid="bib3">3</xref> Although many of these reactions are thought to proceed via gold carbenoids, the challenge to observe and characterize these putative intermediates has basically been unmet.<xref ref-type="link" rid="bib4">4</xref> The current mechanistic interpretation therefore largely relies on indirect evidence and computational data, some of which are subject to debate.<xref ref-type="link" rid="bib5">5</xref> In an attempt to fill this gap, we pursued a potential route to gold carbenoids by formal transmetalation of chromium or tungsten Fischer carbene complexes with [LAu]⁺. Whereas this transformation proceeds with exceptional ease as long as a stabilizing heteroelement is present on the carbene center, it stops half‐way in its absence. Rather unusual bimetallic arrays are formed, which allow the charge density to delocalize over several positions. The obvious difficulty of releasing an "unstabilized" gold carbenoid has potential mechanistic implications for the understanding of π‐acid catalysis in general.</p> </abstract>