Activation of C–O and C–F Bonds by Pincer–Iridium Complexes

Hackenberg, Jason D.; Krogh‐Jespersen, Karsten; Goldman, Alan S.

doi:10.1002/9781118742952.ch4

Cited by 2 publications

(1 citation statement)

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“…Organometallic pincer iridium complexes, which contain a meridionally tridentate ligand, have been applied to a wide variety of stoichiometric and catalytic chemical transformations including, among others, C–H bond activation, C–O bond cleavage, olefin hydroaryloxylation, monoisomerization of 1-alkenes to trans -2-alkenes, α-alkylation of unactivated esters with primary alcohols, (de)hydrogenation and transfer (de)hydrogenation reactions, as well as tandem reactions involving alkane dehydrogenation (AD). , The high thermal stability of the pincer Ir complexes afforded by the tridentate coordination mode and their high modularity are the two key factors responsible for their successful applications in various transformations. In particular, the PCP-type Ir complexes based on the motif of a central coordinating carbanion and two flanking P-coordinating groups have been systematically investigated and found to be highly active, regioselective, and thermally robust catalysts for alkane dehydrogenation and the related tandem reactions.…”

Section: Introductionmentioning

confidence: 99%

Chiral NCN Pincer Iridium(III) Complexes with Bis(imidazolinyl)phenyl Ligands: Synthesis and Application in Enantioselective C–H Functionalization of Indoles with α-Aryl-α-diazoacetates

Zhu

Huang

et al. 2020

Organometallics

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A series of chiral NCN pincer iridium(III) complexes 2a−h with bis(imidazolinyl)phenyl ligands were synthesized via the central aryl C2−H bond activation of the 1,3-bis(2′-imidazolinyl)benzene ligands. The incorporation of a 5tert-butyl group into the central aryl ring of the ligands was found to markedly improve the efficiency of the desired C2-metalation, leading to an obvious enhancement in the yields of the Ir(III) complexes. Consequently, complexes with a tert-butyl group on the central aryl ring were obtained in 34−47% yields, whereas those without the group were produced in only 13−16% yields. All of the new complexes have been characterized by elemental analysis and 1 H and 13 C{ 1 H} NMR spectroscopy. In addition, the molecular structures of complexes 2c, 2d, and 2g′ have been determined by X-ray single-crystal diffraction. 2c and 2d are, indeed, the anticipated six-coordinate pincer Ir(III) complexes. In contrast, 2g′ is a coordinatively unsaturated five-coordinate pincer Ir(III) complex. The Ir(III) complexes were used as the catalysts for the asymmetric C−H insertion reaction of α-aryl-α-diazoacetates with N-protected indoles. With a catalyst loading of 3 mol % and in the presence of 6 mol % of NaBAr F , a variety of optically active indole derivatives bearing chiral functional groups at the C3 position were obtained in good yields with moderate to good enantioselectivities (up to 86% ee).

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Section: Introductionmentioning

confidence: 99%