Übergangsmetallkatalysierte Wasserstofftransferanellierungen: Zugang zu heterocyclischen Gerüsten

Nandakumar, Avanashiappan; Midya, Siba P.; Landge, Vinod G.; Balaraman, Ekambaram

doi:10.1002/ange.201503247

Cited by 53 publications

(2 citation statements)

References 75 publications

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“…To circumvent this drawback, alkaline metal compounds (hydroxides and alkoxides) have been investigated and successfully replaced aluminum alcoholates to convert alcohols into aldehydes or ketones through hydrogen autotransfer process [6,7] . Recently, several research groups have reported effective strategies for the extension of carbon chain, [8] N ‐alkylation of amines, [9] amidation, [10] and the preparation of heterocycles via base‐mediated intermolecular hydrogen transfer [11] . For example, Zhu and co‐workers investigated the synthesis of functionalized quinolines by an intramolecular hydrogen transfer process of 2‐nitrobenzyl alcohol with ketones in the presence of t ‐BuOK (Scheme 1a) [12] .…”

Section: Introductionmentioning

confidence: 99%

t‐BuONa‐Mediated Redox Condensation between o‐Nitroanilines and Benzyl Alcohols towards 2‐Phenyl Benzimidazoles under Transition‐Metal‐Free Conditions

Phan

et al. 2023

ChemistrySelect

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A novel and environmentally benign method was developed for the direct synthesis of 2‐substituted benzimidazoles via a transition metal‐free redox tandem annulation of benzyl alcohols and ortho‐nitroanilines in the presence of a strong base, e.g. alkaline alkoxides or hydroxides. A good tolerance of functional groups was observed, affording an array of 2‐aryl benzimidazole derivatives in high yields. Early mechanistic studies showed that sodium tert‐butoxide could initiate the hydrogen transfer from benzyl alcohol to the nitro group in ortho‐nitroaniline followed by imine condensation, cyclization, and oxidation. This protocol features a convenient tactic that does not require any external oxidants or solvents for the synthesis of bioactive benzimidazole‐involving compounds.

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Section: Introductionmentioning

confidence: 99%

t‐BuONa‐Mediated Redox Condensation between o‐Nitroanilines and Benzyl Alcohols towards 2‐Phenyl Benzimidazoles under Transition‐Metal‐Free Conditions

Phan

et al. 2023

ChemistrySelect

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“…Recently, transition-metal-catalyzed tandem reactions have become an efficient strategy for the construction of structurally complex molecules in organic synthesis, 8 which has been successfully applied in the preparation of substituted quinolines. 9 For example, Shi, 9a Xia, 9b Xu, 9c Li, 9d and Chen 9g have reported impressive procedures to substituted quinolines starting from azide-methylenecyclopropanes, 1,7-enynes, alkyne-tethered diazo compounds, o-cyanoarylacrylamides, and N-aryl azoles, respectively.…”

Section: ■ Introductionmentioning

confidence: 99%

Access to C4-Functionalized Quinolines via Copper-Catalyzed Tandem Annulation of Alkynyl Imines with Diazo Compounds

et al. 2016

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An efficient synthesis of C4-functionalized quinolines through copper-catalyzed tandem annulation of alkynyl imines with diazo compounds is described. This transformation involves an in situ formation of allene and intramolecular electrocyclization, which features high efficiency, mild reaction conditions, easy operation, and broad functional-group tolerance. A wide variety of C4-functionalized quinolines were provided in up to 92% yield for 33 examples.

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A Convenient Ruthenium‐Catalysed α‐Methylation of Carbonyl Compounds using Methanol

Dang

Seayad

2016

Adv Synth Catal

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An efficient ruthenium catalyst is reported, for the first time, to catalyse the α‐methylation of ketones and esters using methanol as a green methylating agent. The in situ generated catalyst from the complexes [RuCp*Cl2]2 or [RuCp*Cl2]n with dpePhos provided up to quantitative yields in the presence of only 20 mol% of lithium tert‐butoxide (LiO‐t‐Bu) as a base. Regioselective mono‐ or multi‐methylation could be effectively controlled by temperature. This catalyst system was also effective for the one‐pot sequential α‐alkylation–α‐methylation of methyl ketones and conjugate reduction–α‐methylation of α,β‐unsaturated ketones to synthesise α‐branched ketones. An application of the α‐methylation of esters using the ruthenium catalyst was demonstrated for an alternative catalytic synthesis of Ketoprofen.magnified image

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Übergangsmetallkatalysierte Wasserstofftransferanellierungen: Zugang zu heterocyclischen Gerüsten

Cited by 53 publications

References 75 publications

t‐BuONa‐Mediated Redox Condensation between o‐Nitroanilines and Benzyl Alcohols towards 2‐Phenyl Benzimidazoles under Transition‐Metal‐Free Conditions

t‐BuONa‐Mediated Redox Condensation between o‐Nitroanilines and Benzyl Alcohols towards 2‐Phenyl Benzimidazoles under Transition‐Metal‐Free Conditions

Access to C4-Functionalized Quinolines via Copper-Catalyzed Tandem Annulation of Alkynyl Imines with Diazo Compounds

A Convenient Ruthenium‐Catalysed α‐Methylation of Carbonyl Compounds using Methanol

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