An Efficient and Selective Nickel-Catalyzed Direct N-Alkylation of Anilines with Alcohols

A Microwave-Assisted SmI2-Catalyzed Direct N-Alkylation of Anilines with Alcohols

A new protocol for the alkylation of aromatic amines has been described using alcohols in the presence of SmI₂ as a catalyst with the generation of water as the sole byproduct. The reaction proceeds under MW conditions and selectively generates monoalkylated amines. This protocol features a broad substrate scope and good functional-group tolerance with moderate to high yields.

Base Metal-Catalyzed Direct Olefinations of Alcohols with Sulfones

Herein, a base-metal nickel-catalyzed direct olefination of alcohols with sulfones is reported. The reaction operates under low catalyst loading and does not require an external redox reagent. A wide range of trans-stilbenes and styrenes were synthesized in good yields and selectivities. Biologically active stilbene DMU-212 could also be synthesized in a single step under these conditions. Mechanistic studies involving kinetic isotope effect, deuterium labeling experiments, and catalytic and stoichiometric reactions with possible catalytic intermediates were performed to elucidate a plausible mechanism.

Reaction condition controlled nickel(ii)-catalyzed C-C cross-coupling of alcohols

The challenge in the C-C cross-coupling of secondary and primary alcohols using acceptorless dehydrogenation coupling (ADC) is the difficulty in accurately controlling product selectivities. Herein, we report a controlled approach to a diverse range of β-alkylated secondary alcohols, α-alkylated ketones and α,β-unsaturated ketones using the ADC methodology employing a Ni(ii) 4,6-dimethylpyrimidine-2-thiolate cluster catalyst under different reaction conditions. This catalyst could tolerate a wide range of substrates and exhibited a high activity for the annulation reaction of secondary alcohols with 2-aminobenzyl alcohols to yield quinolines. This work is an example of precise chemoselectivity control by careful choice of reaction conditions.

Self-Suspended Nanoparticles for N-Alkylation Reactions: A New Concept for Catalysis

The catalytic activity of snowman-like and core-shell Fe3O4/Au nanoparticles (NPs), obtained through a "wet chemistry" approach which directly restitutes nanocatalysts stable and highly active in the reaction medium, was tested towards N-alkylation reactions. The nanocatalysts were tested for the synthesis of secondary amines. The core-shell NPs, thanks to the surface properties, homogeneous dispersion and intimate connection with reagents in the catalyst medium, exhibited an excellent catalytic activity (e. g. >99 % yield and conversion of aniline in very short time and mild conditions). Owing to the magnetic part, the nanoparticles can be easily separated and reused, showing an almost stable activity after 10 cycles.

Recent advances in homogeneous borrowing hydrogen catalysis using earth-abundant first row transition metals

The review highlights the recent advances (2013-present) in the use of earth-abundant first row transition metals in homogeneous borrowing hydrogen catalysis. The utility of catalysts based on Mn, Fe, Co, Ni and Cu to promote a diverse array of important C-C and C-N bond forming reactions is described, including discussion on reaction mechanisms, scope and limitations, and future challenges in this burgeoning area of sustainable catalysis.

The N-alkylation of sulfonamides with alcohols in water catalyzed by a water-soluble metal–ligand bifunctional iridium complex [Cp*Ir(biimH2)(H2O)][OTf]2

A water-soluble dinuclear Cp*Ir complex bearing 4,4′,6,6′-tetrahydroxy-2,2′-bipyrimidine as a bridging ligand was found to be a highly effective catalyst for the N-alkylation of ketones with alcohols in water.

Manganese-catalyzed direct C–C coupling of α-C–H bonds of amides and esters with alcohols via hydrogen autotransfer

Mn-catalyzed C-alkylation of amides and tert-butyl acetate using alcohols as alkylating agents is reported. This approach exhibits a broad substrate scope providing the C(α)-alkylated amides in good yields via hydrogen auto-transfer strategy.

Room temperature N-heterocyclic carbene manganese catalyzed selective N-alkylation of anilines with alcohols

The first example of room temperature homogeneous non-noble metal catalyzed selective N-alkylation of anilines with alcohols using bis-NHC manganese.

A nanoscale iron catalyst for heterogeneous direct N- and C-alkylations of anilines and ketones using alcohols under hydrogen autotransfer conditions

A heterogeneous and commercially available nanoscale iron catalyst for direct N- and C-alkylation reactions of anilines and methylketones with alcohols under hydrogen autotransfer conditions.

Nickel-catalyzed borrowing hydrogen annulations: access to diversified N-heterocycles

An efficient nickel-catalyzed synthesis of diversified N-heterocycles via atom-economic borrowing hydrogen annulations of easily available alcohols and amines.

Hydrogenation and N-alkylation of anilines and imines via transfer hydrogenation with homogeneous nickel compounds

The nickel-catalyzed N-alkylation of a variety of arylamines via transfer hydrogenation in the absence of pressurized hydrogen and basic or acidic additives was achieved in a tandem reaction.

Cp*Co(iii)-catalyzed N-alkylation of amines with secondary alcohols

We report here the first high-valent cobalt(iii)-catalyzed direct alkylation of aromatic amines with secondary alcohols.

Nickel-catalysed dehydrogenative coupling of aromatic diamines with alcohols: selective synthesis of substituted benzimidazoles and quinoxalines

The nickel-catalysed dehydrogenative coupling of 1,2-di-amino-benzene with primary alcohols and diols for the synthesis of N-heterocycles is reported. The catalytic protocol enables the transformation in up to 91% yield and generates water and hydrogen gas as byproducts.

Nickel(ii)-catalyzed direct olefination of benzyl alcohols with sulfones with the liberation of H2

A nickel(ii)-catalyzed direct olefination of benzyl alcohols with sulfones to access various terminal and internal olefins with the liberation of hydrogen gas is reported. The present protocol has been used for E-selective synthesis of DMU-212, and Resveratrol.

Nickel-catalysed direct α-olefination of alkyl substituted N-heteroarenes with alcohols

Ni-catalysed α-olefination of alkylheteroarenes with primary alcohols via dehydrogenative coupling is presented. A simple catalytic protocol gave good to excellent yields of E-selective olefins with olefin/alkane selectivity of >20 : 1.

Nickel-Catalyzed Alkylation of Ketone Enolates: Synthesis of Monoselective Linear Ketones

Herein we have developed a Ni-catalyzed protocol for the synthesis of linear ketones. Aryl, alkyl, and heteroaryl ketones as well as alcohols yielded the monoselective ketones in up to 90% yield. The catalytic protocol was successfully applied in to a gram-scale synthesis. For a practical utility, applications of a steroid derivative, oleyl alcohol, and naproxen alcohol were employed. Preliminary catalytic investigations involving the isolation of a Ni intermediate and defined Ni-H species as well as a series of deuterium-labeling experiments were performed.

Ni-Catalyzed α-Alkylation of Unactivated Amides and Esters with Alcohols by Hydrogen Auto-Transfer Strategy

A transition-metal-catalyzed borrowing hydrogen/hydrogen auto-transfer strategy allows the utilization of feedstock alcohols as an alkylating partner, which avoids the formation of stoichiometric salt waste and enables a direct and benign approach for the construction of C-N and C-C bonds. In this study, a nickel-catalyzed α-alkylation of unactivated amides and ester (tert-butyl acetate) is carried out by using primary alcohols under mild conditions. This C-C bond-forming reaction is catalyzed by a new, molecularly defined nickel(II) NNN-pincer complex (0.1-1 mol %) and proceeds through hydrogen auto-transfer, thereby releasing water as the sole byproduct. In addition, N-alkylation of cyclic amides under Ni-catalytic conditions is demonstrated.

Synthesis of Symmetric and Unsymmetric Secondary Amines from the Ligand-Promoted Ruthenium-Catalyzed Deaminative Coupling Reaction of Primary Amines

The catalytic system generated in situ from the tetranuclear Ru-H complex with a catechol ligand (1/L1) was found to be effective for the direct deaminative coupling of two primary amines to form secondary amines. The catalyst 1/L1 was highly chemoselective for promoting the coupling of two different primary amines to afford unsymmetric secondary amines. The analogous coupling of aniline with primary amines formed aryl-substituted secondary amines. The treatment of aniline- d₇ with 4-methoxybenzylamine led to the coupling product with significant deuterium incorporation on CH₂ (18% D). The most pronounced carbon isotope effect was observed on the α-carbon of the product isolated from the coupling reaction of 4-methoxybenzylamine (C(1) = 1.015(2)). A Hammett plot was constructed from measuring the rates of the coupling reaction of 4-methoxyaniline with a series of para-substituted benzylamines 4-X-C₆H₄CH₂NH₂ (X = OMe, Me, H, F, CF₃) (ρ = -0.79 ± 0.1). A plausible mechanistic scheme has been proposed for the coupling reaction on the basis of these results. The catalytic coupling method provides an operationally simple and chemoselective synthesis of secondary amine products without using any reactive reagents or forming wasteful byproducts.

Nickel-Catalyzed Phosphine Free Direct N-Alkylation of Amides with Alcohols

Herein, we developed an operational simple, practical, and selective Ni-catalyzed synthesis of secondary amides. Application of renewable alcohols, earth-abundant and nonprecious nickel catalyst facilitates the transformations, releasing water as byproduct. The catalytic system is tolerant to a variety of functional groups including nitrile, allylic ether, and alkene and could be extended to the synthesis of bis-amide, antiemetic drug Tigan, and dopamine D2 receptor antagonist Itopride. Preliminary mechanistic studies revealed the participation of a benzylic C-H bond in the rate-determining step.

Ni-Catalyzed dehydrogenative coupling of primary and secondary alcohols with methyl-N-heteroaromatics

Here we report the first base-metal catalyzed dehydrogenative coupling of primary (aromatic, heteroaromatic, and aliphatic) and secondary alcohols with methyl-N-heteroaromatics to form various C(sp³)-alkylated N-heteroaromatics.

Mn(ii)-catalysed alkylation of methylene ketones with alcohols: direct access to functionalised branched products

Manganese-catalysed alkylation of methylene ketones with alcohols is reported. This catalytic protocol enables the transformation in up to 84% yield and generates water as the byproduct.

An efficient and atom-economical route to N-aryl amino alcohols from primary amines

In this paper we reported a novel method for generation of N-aryl amino alcohols from N,N-disubstituted picolinamides through reduction/ring-opening reaction with NaBH₄. The N,N-disubstituted picolinamides can be easily obtained from primary amines after convenient condensation with picolinic acid and coupling with cyclic ethers. The whole route proceeded under simple and mild conditions with high efficiency. Picolinic acid can be recovered in the form of piconol after reaction. It indicated an efficient and atom-economical route for the preparation of N-aryl amino alcohols from primary amines.

A novel method for generation of N-aryl amino alcohols from N,N-disubstituted picolinamides through reduction/ring-opening reaction with NaBH₄ was developed.

Efficient nickel-catalysed N-alkylation of amines with alcohols

A highly active and easy-to-prepare Ni based catalyst system is presented for the selective N-alkylation of amines with alcohols that is in situ generated from Ni(COD)₂ and KOH under ligand-free conditions.

Nickel-catalysed alkylation of C(sp3)–H bonds with alcohols: direct access to functionalised N-heteroaromatics

Base-metal catalysed C(sp³)–H bond functionalisation of methyl-N-heteroaromatics with alcohols is reported for the first time.