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Characterization and Reactivity Studies of a Terminal Copper-Nitrene Species

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Aquest mateix article està publicat a l’edició alemanya d’’Angewandte Chemie’ (ISSN 0044-8249, EISSN 1521-3757), 2016, vol.128, núm. 45, p. 14211–14214. DOI http://dx.doi.org/10.1002/ange.201607238

High-valent terminal copper–nitrene species have been postulated as key intermediates in copper-catalyzed aziridination and amination reactions. The high reactivity of these intermediates has prevented their characterization for decades, thereby making the mechanisms ambiguous. Very recently, the Lewis acid adduct of a copper–nitrene intermediate was trapped at −90 °C and shown to be active in various oxidation reactions. Herein, we describe for the first time the synthesis and spectroscopic characterization of a terminal copper(II)–nitrene radical species that is stable at room temperature in the absence of any Lewis acid. The azide derivative of a triazamacrocyclic ligand that had previously been utilized in the stabilization of aryl–CuIII intermediates was employed as an ancillary ligand in the study. The terminal copper(II)–nitrene radical species is able to transfer a nitrene moiety to phosphines and abstract a hydrogen atom from weak C−H bonds, leading to the formation of oxidized products in modest yields

This work was supported by the European Commission (2011-CIG-303522 to A.C.), the MINECO of Spain (“Ramón y Cajal” contract to A.C. and CTQ2013-43012-P to A.C. and X.R.), the Clara Immerwahr award of UniCat (to A.C.), the European Research Council (Starting Grant ERC-2011-StG-277801 to X.R.), and the Generalitat de Catalunya (2014 SGR 862)

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