Iron‐Catalyzed N‐Arylations of Amides

Abstract

Iron can do it too! A novel, experimentally simple procedure for the N‐arylation of primary amides with aryl iodides involving an in situ formed iron‐based catalyst is reported. The success of the reaction relies on the use of cheap and environmentally friendly FeCl3 in combination with an inexpensive diamine ligand as catalyst system (see scheme).

Palladium‐Based Catalytic System for the Direct C3‐Arylation of Furan‐2‐carboxamides and Thiophene‐2‐carboxamides

“…The solvent was removed under vacuum and the yellow powder was used without purification. 31 Thiophene-2-carboxylic acid benzylamide (1): [15] Thiophene-2-carboxylic acid phenylamide (2): [16] General procedure for the catalyzed reactions: In a typical experiment, 4-bromobenzaldehyde (0.185 g, 1 mmol), thiophene-2carboxylic acid benzylamide (1, 0.325 g, 1.5 mmol), [PdCl(C 3 H 5 )-(dppb)] (3.4 mg, 0.005 mmol), and Cs 2 CO 3 (0.652 g, 2 mmol) were heated in xylene (4 mL) at 130 8C under an argon atmosphere for 16 h. Purification by column chromatography on silica gel (pentane/diethyl ether, 1:9) afforded 3-(4-formylphenyl)thiophene-2-carboxylic acid benzylamide [10] (3) in 70 % yield (0.225 g). 1…”

One-pot ortho-amination of aryl C–H bonds using consecutive iron and copper catalysis

“…The iodination step was carried out at 70°C for 20 h and the N-arylation step at 130°C for 24 h. Purification by flash column chromatography (dichloromethane/petroleum ether, 9 : 1 to dichloromethane/petroleum ether, 4 : 1) gave 3-pyrazol-1′-yl-4-aminobenzophenone (3c) (0.076 g, 64%) as a colourless oil. ν max /cm −1 (neat) 3360 (NH), 1611 (CvO), 1518, 1396, 1269, 1148; δ H (500 MHz, CDCl 3 ) 5.44 (2H, br s, NH 2 ), 6.47 (1H,t,J 2.2 Hz,6.82 (1H,d,J 8.4 Hz,m,7.56 (1H,tt,J 7.4,1.3 Hz,7.65 (1H,dd,J 8.4,1.9 Hz,m, N-(2-Amino-5-chlorophenyl)-1H-pyrazole (3d) 26 N-(2-Amino-5-chlorophenyl)-1H-pyrazole (3d) was synthesised as described for N-(2-amino-5-cyanophenyl)-1H-pyrazole (3a) using 4-chloroaniline (1d) (0.064 g, 0.50 mmol) and pyrazole (0.10 g, 1.5 mmol). The iodination step was carried out at 70°C for 5 h and the N-arylation step at 130°C for 24 h. Purification by flash column chromatography (dichloromethane) gave N-(2-amino-5-chlorophenyl)-1H-pyrazole (3d) (0.061 g, 63%) as a brown oil.…”

Catalyst‐Free One‐Pot Tandem Reduction of Oxo and Ene/Yne Functionalities by Hydrazine: Synthesis of Substituted Oxindoles from Isatins

“…[1] Substituted and unsubstituted oxindoles also serve as crucial synthetic precursors for the synthesis of highly desirable indole-based heterocycles and alkaloids. Some of the synthetic strategies include cyclization of oaminophenylacetic acid derivatives, oxidative N-heterocyclization of amino alcohols, [3] intramolecular amination, [4] oxidation of indoles, [5] radical cyclization, [6] intermolecular Heck reaction, [7] intramolecular arylation of amides [8] and amide enolates, [9] the Friedel-Crafts cyclization of α-halo [10] and α-hydroxy [11] acetanilides, and its modifications involving C-H functionalization. Some of the synthetic strategies include cyclization of oaminophenylacetic acid derivatives, oxidative N-heterocyclization of amino alcohols, [3] intramolecular amination, [4] oxidation of indoles, [5] radical cyclization, [6] intermolecular Heck reaction, [7] intramolecular arylation of amides [8] and amide enolates, [9] the Friedel-Crafts cyclization of α-halo [10] and α-hydroxy [11] acetanilides, and its modifications involving C-H functionalization.…”