Cu(OAc)₂-Promoted Ortho C(sp²)–H Amidation of 8-Aminoquinoline Benzamide with Acyl Azide: Selective Formation of Aroyl or Acetyl Amide Based on Catalyst Loading

Abstract

An efficient method for the C(sp) amidation of 8-aminoquinoline benzamide by acyl azide in the presence of copper acetate has been achieved via C-H activation. Interestingly, the loading of copper acetate has a strong influence on the outcome of the reaction. The use of 1 equiv of copper acetate produces the corresponding aroyl amide, whereas the use of 2 equiv led to acetyl amide. A series of substituted benzoyl and acetyl amides has been obtained.

Benign-Metal-Catalyzed Carbon–Carbon and Carbon–Hetero­atom Bond Formation

“…Our group has developed an efficient protocol for the C(sp 2 )-H amidation of the N-quinolin-8-ylbenzamide scaffold by an acyl azide 33 in the presence of copper acetate through C-H activation (Scheme 11). 13 Most interestingly, the loading of the copper(II) acetate had a vital role in de-termining the outcome of the reaction. The use of one equivalent of copper(II) acetate produced the corresponding aroyl amide 34, whereas the acetyl amide 35 was obtained when two equivalents of copper(II) acetate were used.…”

C–H Functionalization of Aromatic Amides

“…In 2018, Ranu and co‐workers also used 8‐aminoquinoline as a directing group to carry out ortho ‐C–H amidation reactions of aromatic amides with the acyl azides under the catalysis of Cu(II) (Scheme ) . In this paper, aromatic amides and acyl azides were used as substrates, Cu(OAc) 2 as catalyst, K 2 CO 3 as base, DMSO as solvent, and the reaction was completed at room temperature in 12 h. A unique feature of this protocol is that the amount of catalyst Cu(OAc) 2 has a decisive effect on the reaction.…”

Theoretical Study on Ir-Catalyzed α-Amidation of 2-Acylimidazoles: Mechanism and Insertion Selectivity

“…α-Amino carbonyls, as a class of N-containing compounds, are not only ubiquitous structural motifs in natural products and pharmaceuticals but also high-value synthons of N-heterocycles and chiral 1,2-amino alcohols. − However, the traditional synthesis of α-amino carbonyls often suffers from the requirement of prefunctionalized starting materials or the scarce availability of N-electrophiles. , C–H amidation realized by transition-metal-catalyzed nitrene transfer has several advantages including eliminating the requirement of prefunctionalized starting materials and the formation of undesired byproducts. Transition metals, such as Ir, − Rh, − Co, , Ru, , Cu, , and Pd, are usually used as catalysts for these nitrene transfer reactions. This advanced synthetic strategy has been gradually employed to the construction of α-amino carbonyls in recent years but still faces the challenge of limiting substrate scope or low functional group compatibility. − Noteworthily, Chatani’s group recently reported Ir-catalyzed selective α-amidation to synthesize α-amino carbonyls with a broad range of carbonyl substrates (2-acylimidazoles) .…”

“…20,21 C−H amidation realized by transition-metal-catalyzed nitrene transfer has several advantages including eliminating the requirement of prefunctionalized starting materials and the formation of undesired byproducts. Transition metals, such as Ir, 22−25 Rh, 26−28 Co, 29,30 Ru, 31,32 Cu, 33,34 and Pd, 35 are usually used as catalysts for these nitrene transfer reactions. This advanced synthetic strategy has been gradually employed to the construction of α-amino carbonyls in recent years but still faces the challenge of limiting substrate scope or low functional group compatibility.…”