Two‐Step One‐Pot Synthesis of Unsymmetrical (Hetero)Aryl 1,2‐Diketones by Addition‐Oxygenation of Potassium Aryltrifluoroborates to (Hetero)Arylacetonitriles

Abstract

An efficient one‐pot two‐step procedure for the synthesis of unsymmetrical (hetero)aryl 1,2‐diketones has been developed. The reaction proceeds through a palladium‐catalyzed nucleophilic addition of potassium aryltrifluoroborates to aliphatic nitriles followed by a copper‐catalyzed aerobic benzylic C–H oxygenation using molecular oxygen as a green oxidant. This represents the first example of the direct synthesis of unsymmetrical diaryl 1,2‐diketones from arylacetonitriles. This method utilizes inexpensive, stable, nontoxic, and readily available starting materials, is highly effective in the presence of both electron‐rich and electron‐poor nitriles and aryltrifluoroborates, and tolerates a wide variety of functional groups. The synthetic utility of this transformation was shown by increasing the scale of the reaction and by carrying out the one‐pot protocol for the preparation of quinoxaline and benzimidazole derivatives. A plausible reaction mechanism has also been proposed.

A Straightforward Synthesis of α‐Amino Diaryl Ketones from (Hetero)Arylacetonitriles Promoted by N‐Bromosuccinimide

“…At the outset, optimization reaction for the direct synthesis of diaryl α ‐amino ketones were carried out on simple phenylacetonitrile 1 a (Table ). Under the established reaction conditions, the addition of phenyltrifluoroborate 2 a to the phenylacetonitrile 1 a afforded deoxybenzoin 2aa under microwave radiation (MW) ,. Further, the crude reaction mixture was directly treated with NBS (0.1 equiv.)…”

“…In recent time, organic chemists around the world have started utilizing arylacetonitriles as key starting material for the synthesis of various heterocyclic frameworks due to their cheap, stable, non‐toxic and abundant nature . Very recently, we have developed a one‐pot two‐step synthetic strategy for unsymmetrical 1,2‐diketones by utilizing arylacetonitriles and potassium aryltrifluoroborates as a starting material . With this understanding and our research interest in development of novel synthetic routes for functionalized organic molecules, we designed straightforward approach for the synthesis of diaryl α ‐amino ketones from arylacetonitriles as a key precursor using readily available N ‐bromosuccinimide (NBS).…”

Visible-Light-Induced Photocatalytic Oxidative Decarboxylation of Cinnamic Acids to 1,2-Diketones

“…1-(3-Chlorophenyl)-2-phenylethane-1,2-dione (3f). 27 Purification by column chromatography (ethyl acetate/hexane, v/v = 1:50). Yellow solid (132 mg, 54% yield): mp 91−92 °C; 1 H NMR (500 MHz, CDCl 3 ) δ 7.98 (d, J = 7.5 Hz, 3H), 7.85 (d, J = 8.0 Hz, 1H), 7.70 (t, J = 7.5 Hz, 1H), 7.64 (d, J = 8.0 Hz, 1H), 7.55 (t, J = 7.5 Hz, 2H),7.47 (t, J = 8.0 Hz, 1H); 13 C{ 1 H} NMR (126 MHz,CDCl 3 ) δ 193.8,193.1,135.6,135.3,134.9,134.7,132.8,130.5,130.1,129.7,129.3,128.3 0, 193.2, 141.8, 135.2, 132.9, 131.5, 131.4, 130.1, 129.6, 129.2; HRMS (ESI) m/z [M + H] + Calcd for C 14 H 10 ClO 2 245.0364, found 245.0370.…”

Investigation on the Synthesis, Application and Structural Features of Heteroaryl 1,2-Diketones

“…Though a wide variety of methods have been developed to synthesize 1, 2-diketones, − the literature on synthetic routes to heteroaryl 1,2-diketones are sparse. , Katritzky reported the synthesis of heteroaryl 1,2-diketones from heteroaryl­(aryl)­methyl benzotriazoles and esters using BuLi as a key agent in 2005 . Kumar investigated a one-pot, two-step procedure to synthesize heteroaryl 1,2-diketones from nitriles and organoboron reagents . To the best of the author’s knowledge, these are the closest examples on the synthesis of a set of heteroaryl 1,2-diketones from simple, commercially available starting materials.…”