Recyclable Perovskite as Heterogeneous Photocatalyst for Aminomethylation of Imidazo‐Fused Heterocycles

Abstract

A sustainable and cost-effective protocol for direct aminomethylation of imidazo-fused heterocycles by decarboxylative coupling reaction of N-phenylglycines with imidazo-fused heterocycles in the presence of CsPbBr 3 under the irradiation of visible light has been developed. This is the first example of CsPbBr 3 -catalyzed aminomethylation of imidazo-fused heterocycles. The eminent advantage of this work is in that, CsPbBr 3 is easily prepared and can be used at least 5 times without obvious reduction in its activity, exhibiting high catalyst economic feature.

Graphitic Carbon Nitride Polymer as a Recyclable Photoredox Catalyst for Decarboxylative Alkynylation of Carboxylic Acids

“…The control experiments using ammonium oxalate as the hole scavenger or K 2 S 2 O 8 as the electron scavenger gave the product 3 a in lower yields (9%-83% yields, entries 19-20, Table 1), which indicates that both hole and electron play essential roles in the process. [11] Accordingly, the optimal reaction conditions are established as shown in entry 11 (427 nm blue LEDs, g-C 3 N 4 0.75 mg/mL, K 2 CO 3 0.5 equiv., CH 2 Cl 2 , N 2 , rt, 16 h).…”

Photoredox Organic Synthesis Employing Heterogeneous Photocatalysts with Emphasis on Halide Perovskite

“…More decarboxylative coupling reactions under visible light irradiation have been illustrated. [101] Imidazole[1,2-a]pyridines are an importantm otif;t hey are widely present in natural compounds and bioactive molecules. The development of an efficient method to construct imidazole[1,2-a]pyridinesa nd their derivatives is of synthetic importance.A ss hown in Figure 12, as ustainable and cost-effective route for aminomethylation of imidazo-fused heterocycles via CsPbBr 3 -catalyzed decarboxylative coupling reactions under visible light Figure 10.…”

“…Aminomethylation of imidazo-fused heterocycles catalyzedby perovskite via decarboxylative coupling. [101] Figure 13. Lead-free Cs 3 Bi 2 Br 9 perovskite-catalyzed ring-openingr eactiono f epoxides.…”

Recent Advances in Radical C−H Bond Functionalization of Imidazoheterocycles

“…Very recently, Shi et al . reported a sustainable approach for the aminomethylation of imidazo[1,2‐ a ]pyridines with N ‐arylglycines 46 through decarboxylative coupling using ScPbBr 3 as photo‐catalyst under visible light irradiation in DCE (Scheme ) . Various imidazo[1,2‐ a ]pyridines 1 and benzo[ d ]imidazo[2,1‐ b ]thiazole 2 and N ‐arylglycines 46 having a broad range of functional groups (EDGs and EWGs) reacted well and afforded the respective products 47 in 44–94% yields.…”

“…Subsequently, intermediate A is transformed into α-amino radical intermediate B through proton transfer and decarboxylation in the presence of superoxide radical anion (O 2 *À ). Further oxidation of B by HO 2 * led to the formation of imine intermediate C. Finally, the electrophilic addition reaction of C on 1 produced the aminomethylated product 47.Very recently, Shi et al reported a sustainable approach for the aminomethylation of imidazo[1,2a]pyridines with N-arylglycines 46 through decarboxylative coupling using ScPbBr 3 as photo-catalyst under visible light irradiation in DCE (Scheme 30) [49]. Various imidazo[1,2-a]pyridines 1 and benzo[d]imidazo-[2,1-b]thiazole 2 and N-arylglycines 46 having a broad range of functional groups (EDGs and EWGs) reacted well and afforded the respective products 47 in 44-94% yields.…”