Visible-Light-Induced Dehydrogenative Imidoylation of Imidazo[1,2-a]pyridines with α-Amino Acid Derivatives and α-Amino Ketones

Abstract

A new and efficient visible-light-promoted dehydrogenative cross-coupling reaction of imidazo­[1,2-a]­pyridines with α-amino carbonyl compounds toward imidoyl imidazo­[1,2-a]­pyridines is developed. A diverse range of imidazo­[1,2-a]­pyridines undergoes the dehydrogenative imidoylation smoothly with α-amino carbonyl compounds to access the corresponding products in satisfactory yields. We have also proposed the possible reaction mechanism based on preliminary mechanistic studies. The synthetic method has the advantages of wide substrate scope, good functional tolerance, and mild reaction conditions, which make this transformation more practical and sustainable.

Recent Developments in the Photochemical Synthesis of Functionalized Imidazopyridines

“…The same authors recently extended their synthetic method by coupling imidazo[1,2- a ]pyridines with α-amino ketones and α-amino acid derivatives [ 56 ]. Some improvements were applied: the metal catalyst was replaced by an organophotocatalyst (Eosin Y), with citric acid monohydrate as an additive.…”

Visible light-mediated synthesis of quinazolinones from benzyl bromides and 2-aminobenzamides without using any photocatalyst or additive

“…Jiangxi Province Key Laboratory of Synthetic Chemistry, East China University of Technology, Nanchang, 330013, China. E-mail: zbxie@ecut.edu.cn visible light has a wide range of practical applications in the fields of organic synthetic chemistry [36][37][38][39][40][41] and photocatalytic composite materials. 42,43 Inspired by recent photochemical studies, we report a new approach for the green synthesis of quinazolinones using benzyl bromide and 2-aminobenzamide under mild conditions without additives, oxidants, or catalysts.…”

“…In recent years, visible light has been successfully utilized as a clean energy source with high sustainability and environmental friendliness. Researchers have found that visible light has a wide range of practical applications in the fields of organic synthetic chemistry 36–41 and photocatalytic composite materials. 42,43 Inspired by recent photochemical studies, we report a new approach for the green synthesis of quinazolinones using benzyl bromide and 2-aminobenzamide under mild conditions without additives, oxidants, or catalysts.…”

C(sp2)‐H Imination of Imidazo[1,2‐a]pyridines: A Catalyst‐Free, Multicomponent Approach

“…[12a] Later same group developed imination of imidazo[1,2-a]pyridines under visible light conditions [12b] (Figure 2). [12][13][14][15][16] On the other hand, α-imino ketones are excellent building blocks in organic synthesis for constructing various nitrogencontaining molecules. [17] Fascinated by their simple preparation methods and versatile reactivity, several groups, including us, have utilized them as excellent precursors in synthetic chemistry.…”

“…Particularly, Zhu et al., reported a visible‐light‐promoted cross‐dehydrogenative‐coupling reaction of N ‐arylglycine esters with imidazo[1,2‐ a ]pyridines to get α‐aryl‐glycine esters [12a] . Later same group developed imination of imidazo[1,2‐ a ]pyridines under visible light conditions [12b] (Figure 2). [12–16]…”