7 research outputs found

    Nickel-Catalyzed Direct Alkylation of C–H Bonds in Benzamides and Acrylamides with Functionalized Alkyl Halides via Bidentate-Chelation Assistance

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    The alkylation of the ortho C–H bonds in benzamides and acrylamides containing an 8-aminoquinoline moiety as a bidentate directing group with unactivated alkyl halides using nickel complexes as catalysts is described. The reaction shows high functional group compatibility. In reactions of meta-substituted aromatic amides, the reaction proceeds in a highly selective manner at the less hindered C–H bond

    Nickel-Catalyzed Direct Arylation of C(sp<sup>3</sup>)–H Bonds in Aliphatic Amides via Bidentate-Chelation Assistance

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    The Ni-catalyzed, direct arylation of C­(sp<sup>3</sup>)–H (methyl and methylene) bonds in aliphatic amides containing an 8-aminoquinoline moiety as a bidentate directing group with aryl halides is described. Deuterium-labeling experiments indicate that the C–H bond cleavage step is fast and reversible. Various nickel complexes including both Ni­(II) and Ni(0) show a high catalytic activity. The results of a series of mechanistic experiments indicate that the catalytic reaction does not proceed through a Ni(0)/Ni­(II) catalytic cycle, but probably through a Ni­(II)/Ni­(IV) catalytic cycle

    Nickel(II)-Catalyzed Direct Arylation of C–H Bonds in Aromatic Amides Containing an 8‑Aminoquinoline Moiety as a Directing Group

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    Arylation via the cleavage of the ortho C–H bonds by a nickel-catalyzed reaction of aromatic amides containing an 8-aminoquinoline moiety with aryl iodides is reported. The reaction shows a high functional group compatibility. The reaction proceeds in a highly selective manner at the less hindered C–H bonds in the reaction of meta-substituted aromatic amides, irrespective of the electronic nature of the substituents. Electron-withdrawing groups on the aromatic amides facilitate the reaction. Various mechanistic experiments, such as deuterium labeling experiments, Hammett studies, competition experiments, and radical trap experiments, have been made for better understanding the reaction mechanism. It is found that the cleavage of C–H bonds is reversible on the basis of the deuterium labeling experiments. Both Ni­(II) and Ni(0) show a high catalytic activity, but the results of mechanistic experiments suggest that a Ni(0)/Ni­(II) catalytic cycle is not involved

    Ni(II)-Catalyzed Oxidative Coupling between C(sp<sup>2</sup>)–H in Benzamides and C(sp<sup>3</sup>)–H in Toluene Derivatives

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    Oxidative coupling between C­(sp<sup>2</sup>)–H bonds and C­(sp<sup>3</sup>)–H bonds is achieved by the Ni­(II)-catalyzed reaction of benzamides containing an 8-aminoquinoline moiety as the directing group with toluene derivatives in the presence of heptafluoroisopropyl iodide as the oxidant. The method has a broad scope and shows high functional group compatibility. Toluene derivatives can be used as the coupling partner in an unreactive solvent

    Scalable C–H Oxidation with Copper: Synthesis of Polyoxypregnanes

    No full text
    Steroids bearing C12 oxidations are widespread in nature, yet only one preparative chemical method addresses this challenge in a low-yielding and not fully understood fashion: Schönecker’s Cu-mediated oxidation. This work shines new light onto this powerful C–H oxidation method through mechanistic investigation, optimization, and wider application. Culminating in a scalable, rapid, high-yielding, and operationally simple protocol, this procedure is applied to the first synthesis of several parent polyoxypregnane natural products, representing a gateway to over 100 family members

    Scalable C–H Oxidation with Copper: Synthesis of Polyoxypregnanes

    No full text
    Steroids bearing C12 oxidations are widespread in nature, yet only one preparative chemical method addresses this challenge in a low-yielding and not fully understood fashion: Schönecker’s Cu-mediated oxidation. This work shines new light onto this powerful C–H oxidation method through mechanistic investigation, optimization, and wider application. Culminating in a scalable, rapid, high-yielding, and operationally simple protocol, this procedure is applied to the first synthesis of several parent polyoxypregnane natural products, representing a gateway to over 100 family members

    Scalable C–H Oxidation with Copper: Synthesis of Polyoxypregnanes

    No full text
    Steroids bearing C12 oxidations are widespread in nature, yet only one preparative chemical method addresses this challenge in a low-yielding and not fully understood fashion: Schönecker’s Cu-mediated oxidation. This work shines new light onto this powerful C–H oxidation method through mechanistic investigation, optimization, and wider application. Culminating in a scalable, rapid, high-yielding, and operationally simple protocol, this procedure is applied to the first synthesis of several parent polyoxypregnane natural products, representing a gateway to over 100 family members
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