Gold-catalyzed oxidative coupling of arylsilanes and arenes: Origin of selectivity and improved precatalyst

Ball, Liam T.; Lloyd-Jones, Guy C.; Russell, Christopher A.

Abstract

The mechanism of gold-catalyzed coupling of arenes with aryltrimethylsilanes has been investigated, employing an improved precatalyst (thtAuBr3) to facilitate kinetic analysis. In combination with linear free-energy relationships, kinetic isotope effects, and stoichiometric experiments, the data support a mechanism involving an Au(I)/Au(III) redox cycle in which sequential electrophilic aromatic substitution of the arylsilane and the arene by Au(III) precedes product-forming reductive elimination and subsequent cycle-closing reoxidation of the metal. Despite the fundamental mechanistic similarities between the two auration events, high selectivity is observed for heterocoupling (C-Si then C-H auration) over homocoupling of either the arylsilane or the arene (C-Si then C-Si, or C-H then C-H auration); this chemoselectivity originates from differences in the product-determining elementary steps of each electrophilic substitution. The turnover-limiting step of the reaction involves associative substitution en route to an arene π-complex. The ramifications of this insight for implementation of the methodology are discussed. © 2013 American Chemical Society.

Citation

Ball, L. T., Lloyd-Jones, G. C., & Russell, C. A. (2014). Gold-catalyzed oxidative coupling of arylsilanes and arenes: Origin of selectivity and improved precatalyst. Journal of the American Chemical Society, 136(1), 254-264. https://doi.org/10.1021/ja408712e

• Journal Article Type: Article
• Acceptance Date: Dec 22, 2013
• Online Publication Date: Dec 24, 2013
• Publication Date: Jan 8, 2014
• Deposit Date: Jun 4, 2018
• Journal: Journal of the American Chemical Society
• Print ISSN: 0002-7863
• Electronic ISSN: 1520-5126
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 136
• Issue: 1
• Pages: 254-264
• DOI: https://doi.org/10.1021/ja408712e
• Public URL: https://nottingham-repository.worktribe.com/output/1104763
• PMID: 00032958