Bonds Of Aliphatic Amides Research Articles

Pd(II)-Catalyzed Pyridine N-Oxides Directed Arylation of Unactivated Csp(3)-H Bonds.

A novel Pd(II)-catalyzed pyridine N-oxide directed remote arylation of unactivated Csp(3)-H bonds in aliphatic amides with aryl iodides has been developed. This protocol allows installing various aryl groups at the β- or γ-Csp(3) atom of alkyl carboxylic acid amides. The key palladabicyclic intermediate of this transformation has been identified by HR-MS and (1)H NMR method.

Nickel-catalyzed direct thiolation of C(sp(3))-H bonds in aliphatic amides.

Nickel-catalyzed thiolation of the inactivated methyl C(sp(3))-H bonds of aliphatic amides with disulfide is described. It is a novel strategy for the synthesis of thioethers with the ultimate goal of generating thioether carboxylic acids with various functional groups.

Nickel-Catalyzed Direct Thioetherification of β-C(sp3)–H Bonds of Aliphatic Amides

The nickel-catalyzed β-thioetherification of unactivated C(sp(3))-H bond of propionamides is established with the assistance of 8-aminoquinoline auxiliary, leading to the β-thio carboxylic acid derivatives. A broad range of functional groups is compatible with this thioetherfication reaction. The process represents the first successful example of metal-catalyzed C-S bond formation from unactivated C(sp(3))-H bonds.

Direct arylation of C(sp3)-H bonds in aliphatic amides with diaryliodonium salts in the presence of a nickel catalyst.

The Ni(II)-catalyzed direct arylation of C(sp(3))-H (methyl and methylene) bonds in aliphatic amides containing an 8-aminoquinoline moiety as the directing group with diaryliodonium salts as coupling electrophiles is described. A wide variety of functional groups are tolerated in the reaction. The reaction represents the first example of the Ni-catalyzed direct arylation of C(sp(3))-H bonds with diaryliodonium salts.

ChemInform Abstract: Nickel‐Catalyzed Direct Arylation of C(sp3)—H Bonds in Aliphatic Amides via Bidentate‐Chelation Assistance.

The Ni-catalyzed, direct arylation of C(sp3)–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-Catalyzed Site-Selective Alkylation of Unactivated C(sp3)–H Bonds

The direct alkylation of unactivated sp(3) C-H bonds of aliphatic amides was achieved via nickel catalysis with the assist of a bidentate directing group. The reaction favors the C-H bonds of methyl groups over the methylene C-H bonds and tolerates various functional groups. Moreover, this reaction shows a predominant preference for sp(3) C-H bonds of methyl groups via a five-membered ring intermediate over the sp(2) C-H bonds of arenes in the cyclometalation step.

Nickel-Catalyzed Direct Arylation of C(sp3)–H Bonds in Aliphatic Amides via Bidentate-Chelation Assistance

The Ni-catalyzed, direct arylation of C(sp(3))-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.

ChemInform Abstract: Palladium(0)‐Catalyzed Alkynylation of C(sp3)—H Bonds.

The alkynylation of β-C(sp3)–H bonds in aliphatic amides with alkynyl halides has been enabled using Pd(0)/N-heterocyclic carbene (NHC) and Pd(0)/phosphine (PR3) catalysts. This is the first example of utilizing [AlkynylPd(II)Ln] complexes to activate C(sp3)–H bonds.

Palladium(0)-Catalyzed Alkynylation of C(sp3)–H Bonds

The alkynylation of β-C(sp(3))-H bonds in aliphatic amides with alkynyl halides has been enabled using Pd(0)/N-heterocyclic carbene (NHC) and Pd(0)/phosphine (PR3) catalysts. This is the first example of utilizing [AlkynylPd(II)L(n)] complexes to activate C(sp(3))-H bonds.

Ruthenium-catalyzed cyclocarbonylation of aliphatic amides through the regioselective activation of unactivated C(sp3)–H bonds

The regioselective carbonylation of unactivated C(sp3)–H bonds of aliphatic amides, using 2-pyridinylmethylamine as a directing group in conjunction with Ru3(CO)12 as a catalyst is described. The presence of a 2-pyridinylmethylamine moiety in the amides is crucial for the success of the reaction. Although ethylene is not incorporated into the products, its presence is also essential for the reaction to proceed. Furthermore, the addition of H2O is important for the reaction to proceed efficiently. The reaction shows a high preference for the C–H bonds of methyl groups, compared to methylene C–H bonds, even the methylene C–H bonds are activated by the presence of an oxygen atom or an aryl group. In addition, the reaction tolerates various functional groups, such as MeO, Cl, CF3, CN, and even Br substituents. The reaction of α-mono-substituted aliphatic amides gave the corresponding carbonylation products in lower yields, although the use of α,α-di-substituted aliphatic amides resulted in high product yields. The use of a sterically demanding directing group, such as 1-(2-pyridinylethyl)amine moiety, in α-mono-substituted aliphatic amides improved the yields of the products. The stoichiometric reaction of an amide with Ru3(CO)12 gave a stable di-nuclear ruthenium complex as a single ruthenium complex in which the 2-pyridinylmethylamino moiety is coordinated to the ruthenium center in a N,N-manner and an amide carbonyl oxygen binds to the other ruthenium center, but C–H bond activation is not involved. The complex itself does not show catalytic activity, but is activated in the presence of H2O under the catalytic reaction conditions employed.

Highly Regioselective Carbonylation of Unactivated C(sp3)–H Bonds by Ruthenium Carbonyl

The regioselective carbonylation of unactivated C(sp(3))-H bonds of aliphatic amides was achieved using Ru(3)(CO)(12) as a catalyst. The presence of a 2-pyridinylmethylamine moiety in the amide is crucial for a successful reaction. The reaction shows a preference for C-H bonds of methyl groups as opposed to methylene C-H bonds and tolerates a variety of functional groups. The stoichiometric reaction of an amide with Ru(3)(CO)(12) gave a dinuclear ruthenium complex in which the 2-pyridinylmethylamino moiety was coordinated to the ruthenium center in an N,N manner.