Isoquinoline skeleton synthesis via chelation-assisted C−H activation

He, Ruoyu; Huang, Zhi‐Tang; Zheng, Qiang; Wang, Congyang

doi:10.1016/j.tetlet.2014.08.077

Cited by 155 publications

(49 citation statements)

References 108 publications

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“…[7,8] Nitrogen-containing chelating groups have been commonly used to activate ortho CÀH bonds but often these directing groups are not involved in new CÀCa nd CÀNb ond formation. Incorporation of directing groups such as nitrogen in the synthesis of heterocyclesvia CÀ H/NÀXb ond activation shouldi mprove the atom-and stepeconomy.…”

mentioning

confidence: 99%

Cobalt(III)‐Catalyzed Dehydrative [4+2] Annulation of Oxime with Alkyne by CH and NOH Activation

Sen

Kalsi

Sundararaju

2015

Chemistry A European J

193

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Efficient, scalable cobalt-catalyzed redox-neutral [4+2] annulation of readily available oximes and alkyne is reported. The developed synthetic methodology is widely applicable and tolerates various functional groups including heterocycles. A stable Cp*Co(III) neutral complex is employed as the catalyst for this redox-neutral [4+2] annulation reaction, which progresses smoothly by way of a reversible cyclometallation without any external oxidizing agent, and produces only water as the side product.

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mentioning

confidence: 99%

Cobalt(III)‐Catalyzed Dehydrative [4+2] Annulation of Oxime with Alkyne by CH and NOH Activation

Sen

Kalsi

Sundararaju

2015

Chemistry A European J

193

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“…[6] were also well established by using various transition-metal catalysts and proper oxidants (Scheme 1b). [7,8] However,t he redox-neutral [4+ +2] annulations of imines and alkynes to give 3,4-dihydroisoquinolines remain elusive.Herein, we describe the first redox-neutral [4+ +2] cyclization of NÀHi mines and internal alkynes to access cis-3,4-dihydroisoquinolines by employing iron carbonyls as catalysts (Scheme 1c). This reaction also represents the first iron-carbonyl-catalyzed C À Ht ransformation of arenes since its parent cycloferration reaction was reported in 1965.…”

Section: Transition-metal-catalyzed Direct Transformations Of Inertmentioning

confidence: 99%

Iron‐Carbonyl‐Catalyzed Redox‐Neutral [4+2] Annulation of N−H Imines and Internal Alkynes by C−H Bond Activation

Jia

Zhao

et al. 2016

Angew Chem Int Ed

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Stoichiometric C-H bond activation of arenes mediated by iron carbonyls was reported by Pauson as early as in 1965, yet the catalytic C-H transformations have not been developed. Herein, an iron-catalyzed annulation of N-H imines and internal alkynes to furnish cis-3,4-dihydroisoquinolines is described, and represents the first iron-carbonyl-catalyzed C-H activation reaction of arenes. Remarkablely, this is also the first redox-neutral [4+2] annulation of imines and alkynes proceeding by C-H activation. The reaction also features only cis stereoselectivity and excellent atom economy as neither base, nor external ligand, nor additive is required. Experimental and theoretical studies reveal an oxidative addition mechanism for C-H bond activation to afford a dinuclear ferracycle and a synergetic diiron-promoted H-transfer to the alkyne as the turnover-determining step.

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“…[1] Manye xamples of such reactions have been reported since the pioneering work of Narasaka et al on Pd-catalyzed intramolecular amino-Heck-type reactions. [6] However,m echanistic studies based on isolationo ft he ketimidoc omplexes that are generated by oxidative additiono fo xime derivatives to low-valent metal species (M = Ti, [7a] Re, [7b] Os, [7c] Pd; [8] Scheme 1) are still relativelys carce compared with the well-documented access to ketimido complexes by stoichiometricr eactions such as nucleophilic attack on metal nitrilec omplexes (M = W, [9a,b] Re, [9c] Ru [9d] ), migratory insertion of MR into nitriles [10a] (M = Th, [10b] U, [10b] Ti, [10c,d] [11c] ). [6] However,m echanistic studies based on isolationo ft he ketimidoc omplexes that are generated by oxidative additiono fo xime derivatives to low-valent metal species (M = Ti, [7a] Re, [7b] Os, [7c] Pd; [8] Scheme 1) are still relativelys carce compared with the well-documented access to ketimido complexes by stoichiometricr eactions such as nucleophilic attack on metal nitrilec omplexes (M = W, [9a,b] Re, [9c] Ru [9d] ), migratory insertion of MR into nitriles [10a] (M = Th, [10b] U, [10b] Ti, [10c,d] [11c] ).…”

Section: Introductionmentioning

confidence: 99%

Generation of Stable Ruthenium(IV) Ketimido Complexes by Oxidative Addition of Oxime Esters to Ruthenium(II): Reactivity Studies Based on Electronic Properties of the Ru−N Bond

Shimbayashi

Okamoto

Ohe

2017

Chemistry A European J

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The reaction of an oxime ester with [Ru(PPh ) X ] proceeded smoothly at room temperature to afford a stable Ru ketimido complex as oxidative adduct. The structure of the complex was unambiguously determined by X-ray crystallographic analysis, which showed an almost linear Ru-N-C array. The electronic properties of the nitrogen atom were estimated by DFT calculations, and the results suggested double-bond character of the Ru-N bond. Kinetic studies and consideration of the substituent effect on the oxime ester led to the proposal of a reaction mechanism involving oxidative addition, which could proceed by N,O-chelating coordination to the Ru center prior to N-O bond cleavage. The obtained Ru ketimido complex could be transformed into a ruthenacycle by C-H activation by a concerted metalation-deprotonation mechanism in dichloromethane/methanol. Ru ketimido complexes with a tethered alkyne or alkene moiety underwent chloroamination of unsaturated C-C bonds followed by C-H activation, which resulted in the formation of a ruthenacycle. Considering the LUMO of an isolated Ru ketimido complex, the chloroamination should proceed by a synchronous 1,3-dipolar cycloaddition-type mechanism. Insight into the character and reactivity of Ru ketimido complexes will be helpful for developments in the catalytic transformation of oxime esters.

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Isoquinoline skeleton synthesis via chelation-assisted C−H activation

Cited by 155 publications

References 108 publications

Cobalt(III)‐Catalyzed Dehydrative [4+2] Annulation of Oxime with Alkyne by CH and NOH Activation

Cobalt(III)‐Catalyzed Dehydrative [4+2] Annulation of Oxime with Alkyne by CH and NOH Activation

Iron‐Carbonyl‐Catalyzed Redox‐Neutral [4+2] Annulation of N−H Imines and Internal Alkynes by C−H Bond Activation

Generation of Stable Ruthenium(IV) Ketimido Complexes by Oxidative Addition of Oxime Esters to Ruthenium(II): Reactivity Studies Based on Electronic Properties of the Ru−N Bond

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