Ir I -Anilido complexes

N—H Bond Activation Leading to lr(lll)-Amido-Hydrido Complexes 

An understanding of N—H activation via oxidative addition to Ir(I) fragments - and of its microscopic reverse, reductive elimination - is of fundamental importance 

The Ir(III)-amido-hydrido complex 43 was isolated by reacting the electron-rich neutral phosphine-cyclooctene complex 42 according to Equation 6.13 [7] (note the cis arrangement of the hydride and amide function). Likewise, the cationic complex 44 reacted in neat aniline to afford a 50/50 mixture of the N—H (45) and C—H (46) activation products that was isolated as a light orange powder (Equation 6.14). Compound 45 was separated from 46 and purified in 49% overall yield. 

The phosphine-free complex [lrCl(COE)2]2 (COE = cyclooctene) was also shown to activate ammonia to form mixtures of Ir-hydride and Ir-amide complexes [37]. 

Once the N—H bond has been oxidatively added to the Ir(I) complex (in the context of the CCM cycle, vide supra), the resultant Ir(III) intermediate is a Lewis acid that is thought to coordinate the olefin. A synergistic effect between the coordinated electrophilically activated olefin and the highly nucleophilic nature of the amido function is believed to facilitate the C—N bond formation within the coordination sphere of the Ir center (see 56). Alkyl-amino-Ir(III) complexes, such as the key intermediate 24 of the CCM system (as described in Section 6.2.1) are of paramount importance to better understand Ir-catalyzed hydroaminations. Complex 

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