Bonds In Aromatic Amides Research Articles

Ruthenium(II)-catalyzed Alkylation of C-H Bonds in Aromatic Amides with Vinylsilanes

The ruthenium (II)-catalyzed ortho-C-H alkylation of aromatic amides with vinylsilanes with the aid of an 8-aminoquinoline moiety as a directing group is reported. A wide range of functional groups...

Rhodium-Catalyzed Alkylation of C-H Bonds in Aromatic Amides with Non-activated 1-Alkenes: The Possible Generation of Carbene Intermediates from Alkenes.

The alkylation of C-H bonds (hydroarylation) in aromatic amides with non-activated 1-alkenes using a rhodium catalyst and assisted by an 8-aminoquinoline directing group is reported. The addition of a carboxylic acid is crucial for the success of this reaction. The results of deuterium-labeling experiments indicate that one of deuterium atoms in the alkene is missing, suggesting that the reaction does not proceed through the commonly accepted mechanism for C-H alkylation reactions. Instead the reaction is proposed to proceed through a carbene mechanism. The carbene mechanism is also supported by preliminary DFT calculations.

Direct Acyloxylation of C(sp2)-H and C(sp2)-X (X = Cl, Br) Bonds in Aromatic Amides Using Copper Bromide and 2-(4,5-Dihydro-oxazol-2-yl)-phenylamine.

Here we reported a method for Cu2+-catalyzed ortho-acyloxylation of either the C(sp2)-H or C(sp2)-X (X = Cl, Br) bond of aromatic amides with carboxylic acid, especially olefine acids, to obtain corresponding products in good yields up to 91%. The catalyst CuBr2 is cheap and stable to conserve in comparison with other metals, like Rh, Pd, Ru, and Cu+. This simple procedure is applicable for wide substrate scope and various functional groups to produce carboxylic esters without any additives or ligands.

Cobalt(II)-Catalyzed Acyloxylation of C-H Bonds in Aromatic Amides with Carboxylic Acids.

The cobalt(II)-catalyzed acyloxylation of C-H bonds in aromatic amides containing an 8-aminoquinoline moiety as the directing group with carboxylic acids is reported. Various carboxylic acids including aromatic and aliphatic carboxylic acids are applicable to the reaction. The reaction displays a broad substrate scope and high functional group tolerance. The reaction is carried out under air.

Nickel‐Catalyzed Directed Benzylation of Ortho C−H Bonds in Aromatic Amides through C−H/C−N Cleavage

AbstractThe cleavage of both sp2 C−H and C−N bonds by a nickel‐catalyzed reaction of aromatic amides containing an 8‐aminoquinoline moiety with benzyl ammonium salts is reported. A wide variety of functional groups are tolerated in the reaction. Preliminary mechanistic investigations indicate that the reaction probably proceeds through a NiI/NiIII catalytic pathway. This Ni‐catalyzed procedure provides an alternative approach to construct diarylmethane derivatives.

Nickel‐Catalyzed Benzylation of C−H Bonds in Aromatic Amides with Benzyltrimethylammonium Halides

AbstractNickel‐catalyzed benzylation reactions of C−H bonds in aromatic amides with benzyltrimethylammonium halides are developed by using a 5‐chloro‐8‐aminoquinoline derivative as a bidentate directing group. Benzylation occurs selectively at the ortho‐C−H bonds in aromatic amides, and no methylation was detected. The presence of a 5‐chloro‐8‐aminoquinoline moiety is essential for the success of this reaction, in which a variety of functional groups can be tolerated.

Copper-Catalyzed Direct Acyloxylation of C(sp2)-H Bonds in Aromatic Amides.

Copper-catalyzed ortho-acyloxylation of the sp2 C-H bond of aryl amides with carboxylic acids is reported. Benzoic acids, cinnamic acids, and aliphatic acids can be involved, and the desired products were obtained in moderate to good yields. This procedure is compatible with a wide range of functional groups and heteroarenes without the use of any ligands or additives. This method provides an operationally simple approach for the synthesis of benzoate and cinnamate.

Rhodium-Catalyzed Alkenylation of C-H Bonds in Aromatic Amides with Alkynes.

The rhodium-catalyzed alkenylation of C-H bonds of aromatic amides with alkynes is reported. A variety of functional groups, including OMe, OAc, Br, Cl, and even NO2, are applicable to this reaction to give the corresponding hydroarylation products. The presence of an 8-aminoquinoline group as the directing group is crucial for the success of the reaction.

ChemInform Abstract: Dicumyl Peroxide as a Methylating Reagent in the Ni‐Catalyzed Methylation of ortho C—H Bonds in Aromatic Amides.

The direct methylation of ortho C–H bonds in aromatic amides with dicumyl peroxide (DCP) using a nickel complex as the catalyst is reported. The reaction shows a high functional group tolerance and is inhibited by radical scavengers. In reactions of meta-substituted aromatic amides, the reaction proceeds in a highly selective manner at the less hindered C–H bonds.

Mechanism of Ruthenium-Catalyzed Direct Arylation of C–H Bonds in Aromatic Amides: A Computational Study

Ruthenium-catalyzed arylation of ortho C–H bonds directed by a bidentate 8-aminoquinoline moiety not only is important to construct new biaryl derivates but also merges important research areas. In this study, the density functional theory (DFT) method M11-L was employed to predict the mechanism of this C–H bond arylation reaction. The computational results indicate that the initial step for this reaction is catalyst loading by electrophilic deprotonation to generate a substrate-coordinated Ru(II) intermediate, which is the key compound in the complete catalytic cycle. The catalytic cycle includes electrophilic deprotonation by carbonate, oxidative addition of bromobenzene, reductive elimination to form a new aryl–aryl bond, proton transfer to release the product, and ligand exchange to regenerate the initial Ru(II) intermediate. Theoretical calculations suggest that the oxidative addition of bromobenzene is the rate-determining step of the whole catalytic cycle, and the apparent activation free energy is...

Dicumyl Peroxide as a Methylating Reagent in the Ni-Catalyzed Methylation of Ortho C-H Bonds in Aromatic Amides.

The direct methylation of ortho C-H bonds in aromatic amides with dicumyl peroxide (DCP) using a nickel complex as the catalyst is reported. The reaction shows a high functional group tolerance and is inhibited by radical scavengers. In reactions of meta-substituted aromatic amides, the reaction proceeds in a highly selective manner at the less hindered C-H bonds.

ChemInform Abstract: Ni(II)‐Catalyzed Sulfonylation of ortho C—H Bonds in Aromatic Amides Utilizing an N,N‐Bidentate Directing Group.

AbstractThe Ni(II)‐catalyzed sulfonylation of ortho C—H bonds in aromatic amides of type (I) or (IV) is described.

ChemInform Abstract: Rhodium‐Catalyzed Alkylation of C—H Bonds in Aromatic Amides with Styrenes via Bidentate—Chelation Assistance.

Abstract8‐Aminoquinoline is used as bidendate directing group in alkylation reactions of aromatic C(sp2)—H bonds.

ChemInform Abstract: The Nickel(II)‐Catalyzed Direct Benzylation, Allylation, Alkylation, and Methylation of C—H Bonds in Aromatic Amides Containing an 8‐Aminoquinoline Moiety as the Directing Group.

AbstractThe nickel(II)‐catalyzed ortho‐alkylation of aromatic amides containing an 8‐aminoquinoline moiety as directing group is described.

Rhodium-Catalyzed Alkylation of C-H Bonds in Aromatic Amides with Styrenes via Bidentate-Chelation Assistance.

Rhodium-catalyzed alkylation reactions of aromatic C-H bonds in aromatic amides with styrene derivatives have been developed by using an 8-aminoquinoline as a bidentate directing group. C-C bond formation selectively occurred between the ortho C-H bonds in aromatic amides and the terminal carbon of the styrene derivatives. The presence of an 8-aminoquinoline moiety is essential for the success of the reaction.

ChemInform Abstract: Nickel(II)‐Catalyzed Direct Arylation of C—H Bonds in Aromatic Amides Containing an 8‐Aminoquinoline Moiety as a Directing Group.

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.

ChemInform Abstract: Copper(II)‐Catalyzed Direct Thiolation of C—H Bonds in Aromatic Amides with Aryl and Aliphatic Thiols.

Abstract An efficient approach for Cu-catalyzed thiolation of C sp2 –H bonds of directing-group-containing aromatic amides with 1°, 2°, and 3° aliphatic thiols and thiophenols has been developed. This method shows excellent functional group tolerance and provides a straightforward way for the preparation of aryl thioethers.

ChemInform Abstract: Rhodium‐Catalyzed Alkylation of C—H Bonds in Aromatic Amides with α,β‐Unsaturated Esters.

AbstractThe regioselective alkylation of aromatic amides such as (I), (IV), (VII), and (IX) containing an 8‐aminoquinoline moiety as directing group with α,β‐unsaturated carbonyl compounds is described.

The Nickel(II)-Catalyzed Direct Benzylation, Allylation, Alkylation, and Methylation of C–H Bonds in Aromatic Amides Containing an 8-Aminoquinoline Moiety as the Directing Group

Abstract Direct alkylation via the cleavage of the ortho C–H bonds by a nickel-catalyzed reaction of aromatic amides containing an 8-aminoquinoline moiety as the directing group with alkyl halides is reported. Various alkyl halides, including benzyl, allyl, alkyl, and methyl halides (or pseudo halides) participate as electrophilic coupling partners. The reaction shows a high functional group compatibility. The reaction proceeds in a highly regioselective manner at the less hindered C–H bonds in the reaction of meta-substituted aromatic amides, irrespective of the electronic nature of the substituent. The mechanism responsible for the C–H alkylation reaction is discussed based on the results obtained in a variety of mechanistic experiments.

Copper(II)-catalyzed direct thiolation of C–H bonds in aromatic amides with aryl and aliphatic thiols

An efficient approach for Cu-catalyzed thiolation of Csp2–H bonds of directing-group-containing aromatic amides with 1°, 2°, and 3° aliphatic thiols and thiophenols has been developed. This method shows excellent functional group tolerance and provides a straightforward way for the preparation of aryl thioethers.