Spectroscopic studies of the Chan-Lam amination : a mechanism-inspired solution to boronic ester reactivity

Vantourout, Julien C. and Miras, Haralampos N. and Isidro-Llobet, Albert and Sproules, Stephen and Watson, Allan J. B. (2017) Spectroscopic studies of the Chan-Lam amination : a mechanism-inspired solution to boronic ester reactivity. Journal of the American Chemical Society, 139 (13). 4769–4779. ISSN 0002-7863 (https://doi.org/10.1021/jacs.6b12800)

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Abstract

We report an investigation of the Chan-Lam amination reaction. A combination of spectroscopy, computational modeling, and crystallography has identified the structures of key intermediates and allowed a complete mechanistic description to be presented, in-cluding off-cycle inhibitory processes, the source of amine and organoboron reactivity issues, and the origin of competing oxida-tion/protodeboronation side reactions. Identification of key mechanistic events has allowed the development of a simple solution to these issues: manipulating Cu(I)→Cu(II) oxidation and exploiting three synergistic roles of boric acid has allowed the development of a general catalytic Chan-Lam amination, overcoming long-standing and unsolved amine and organoboron limitations of this valuable transformation.