Copper‐Catalyzed Oxidative Coupling of Carboxylic Acids with N,N‐Dialkylformamides: An Approach to the Synthesis of Amides

Abstract

A new synthetic approach for amide bond formation through the oxidative coupling of N,N-dialkylformamides with carboxylic acids was achieved by using a copper catalyst.

Synthesis of α-Ketoamides by Copper-Catalyzed Reactions of Phenylacetic Acids with N,N-Dialkylformamides

“…Initially, phenylacetic acid is oxidized to 2-oxo-2-phenylacetic acid [10b] , then, 2-oxo-2-phenylacetic acid forms product with N,N-dimethylamine radical, [8b] which is formed through decomposition of DMF under the reaction conditions. [8i,11] This is different from the work of Reddy and coworkers, [12] they showed that amide could be obtained by the decarboxylation of carbamic anhydride formed from the direct coupling of acid with fomamide.…”

Cross Dehydrogenative Coupling (CDC) Reactions of N,N‐Disubstituted Formamides, Benzaldehydes and Cycloalkanes

“…In the above reactions, the authors proposed the formation of carbamic anhydrides such as B (obtained by the direct coupling of acid with formamide) as intermediates, losing a molecule of carbon dioxide to afford the desired products (Scheme ). No product was obtained in the presence of radical scavenger (TEMPO), thus indicating involvement of radicals in the reaction …”

“…Direct coupling between substituted benzoic acids and formamides in the presence of TBHP and Cu(ClO 4 ) 2 · 6 H 2 O at 100 °C, to furnish amides in good yields, was reported by Reddy et al A series of copper salts such as CuBr, CuI, CuO, CuBr 2 , Cu(OAc) 2 , Cu(SO 4 ) 2 · 5 H 2 O etc. were evaluated and it was observed that the counterion strongly influenced the yields of the products.…”

Copper-catalyzed oxidative coupling of carboxylic acids with formamides for the synthesis of α,β-unsaturated amides

“…12 During preparation of our manuscript, Reddy group finished Cu-catalyzed oxidative coupling carboxylic acids with DMF or DEF to the synthesis of amides. 13 We noticed that their attention was focused on aliphatic and aromatic acids. Herein, we wish to report a reaction of copper-catalyzed oxidative coupling of carboxylic acids with formamides for the synthesis of , -unsaturated amides (Scheme 1).…”