Zinc‐Catalyzed N‐Alkylation of Aromatic Amines with Alcohols: A Ligand‐Free Approach

Abstract

An efficient zinc-catalyzed N-alkylation reaction of aromatic amines was achieved using aliphatic, aromatic, and heteroaromatic alcohols as the alkylating reagent. A variety of aniline derivatives, including heteroaromatic amines, underwent the N-alkylation reaction and furnished the corresponding monoalkylated products in good to excellent yields. The application of the reaction is also further demonstrated by the synthesis of a 2-phenylquinoline derivative from acetophenone and 2-aminobenzyl alcohol. Deuterium labeling experiments show that the reaction proceeds via a borrowing hydrogen process.

Visible‐Light‐Induced Oxidative α‐Alkylation of Glycine Derivatives with Ethers under Metal‐Free Conditions

“…Synthesis of 1 u [18] The mixture of thiophen-2-ylmethanol (1.50 mmol), aniline (1.0 mmol), t-BuOK (1.0 mmol), Zn(NO 3 ) 2 • 6H 2 O (15.0 mol%) in toluene (1.50 mL) was stirred at 140 °C under nitrogen atmosphere for 36 h. Then, the solution was extracted with CH 2 Cl 2 and concentrated by rotary evaporation. The crude mixture was purified on a silica gel column (PE/EA) to provide the desired product 1 u.…”

“…06, 157.32, 154.98, 143.59, 135.02, 133.86, 128.91, 127.75, 115.93, 115.70, 113.95, 113.88, 51.01. [18] According to the general procedure, the product 1 s was obtained as a colorless liquid (1.6 g, 87 %). 1 H NMR (CDCl 3 , 400 MHz) δ 7.25-7.12 (m, 3H), 7.02 (d, J = 3.4 Hz, 1H), 6.97 (dd, J = 5.1, 3.5 Hz, 1H), 6.76 (t, J = 7.4 Hz, 1H), 6.69 (d, J = 8.0 Hz, 2H), 4.52 (s, 2H).…”

Effect of surface acidity and basicity of supported Ni catalysts on theN-alkylation of isopropylamine with isopropanol

“…11 Alcohols have emerged as inexpensive, lower toxicity and largely available materials, and the use of them as alkylating reagents will make the N-alkylation reaction greener because the by-product is only water. 12 Hence, the N-alkylation of amines with alcohols is an environmentally benign and excellent alternative approach to produce aliphatic amines.…”

Magnetically Recyclable Heterogeneous Cobalt Ferrite Catalyst for the Direct N‐Alkylation of (Hetero)aryl Amines with Alcohols

“…[6] The initial development phase of this strategy utilized homogeneous catalysts based on noble metals (Ru, Rh, Pd and Ir) which shuttle hydrogen between the initial dehydrogenation and the final hydrogenation steps of the reaction. [7] Recently, the focus has moved to the development of homogeneous catalysts based on base metals like Co, [8] Fe, [9] Mn [10] and Zn [11] due to their higher abundance and lower cost. [12] Though homogeneous catalysts have advantages in terms of efficiency and tunability, they generally require expensive ligands and additives.…”