Divergent g-C₃N₄-catalyzed Reactions of Quinoxalin-2(1H)-ones with N-Aryl Glycines under Visible Light: Solvent-Controlled Hydroaminomethylation and Annulation

Abstract

An effective and simple visible light-induced heterogeneous g-C 3 N 4 -catalyzed decarboxylative reaction of quinoxalin-2(1H)-ones with Naryl glycines was developed. When the reaction was performed in DMSO/ H 2 O and EtOH, the products dihydroquinoxalin-2(1H)-ones and tetrahydroimidazo[1,5-a]quinoxalin-4(5H)-ones were unprecedentedly obtained in good yields, respectively. This solvent-dependent system offers advantages, including simple and easy operation, short reaction time, high chemoselectivity, a recyclable catalyst, metal-/base-/oxidant-free, and mild reaction conditions.

Decatungstate-photocatalyzed direct coupling of inert alkanes and quinoxalin-2(1H)-ones with H2 evolution

“…under the irradiation of a 1.5 kW Xe lamp with the addition of a stoichiometric oxidant (K 2 S 2 O 8 , 4 equiv.). 22 From the point of view of green chemistry, 23 we questioned whether a H 2 evolution process could be incorporated into the direct coupling of alkanes and heterocycles, in which acid additives and oxidants could be avoided. Therefore, we herein report the direct coupling of inert alkanes and quinoxalin-2(1 H )-ones with H 2 evolution catalyzed by TBADT under mild conditions (Scheme 1b).…”

Sunlight Induced and Recyclable g-C3N4 Catalyzed C-H Sulfenylation of Quinoxalin-2(1H)-Ones

“…On the other hand, graphitic carbon nitride (g-C 3 N 4 ) is an environmentally friendly, recyclable and inexpensive heterogeneous photocatalyst, which has emerged as a promising candidate to homogeneous photoredox catalysts [ 72 ]. Various novel g-C 3 N 4 catalyzed photocatalytic reactions have been more deeply explored, such as controlled oxidation reactions [ 73 , 74 , 75 ], coupling reactions [ 76 , 77 , 78 , 79 , 80 , 81 ] and heterocyclizations [ 82 , 83 , 84 ]. To our knowledge, only Yu and co-workers demonstrated a visible light-induced g-C 3 N 4 -catalyzed decarboxylative reaction of quinoxalin-2(1 H )-ones with N-aryl glycines ( Scheme 1 c) [ 84 ].…”

“…Various novel g-C 3 N 4 catalyzed photocatalytic reactions have been more deeply explored, such as controlled oxidation reactions [ 73 , 74 , 75 ], coupling reactions [ 76 , 77 , 78 , 79 , 80 , 81 ] and heterocyclizations [ 82 , 83 , 84 ]. To our knowledge, only Yu and co-workers demonstrated a visible light-induced g-C 3 N 4 -catalyzed decarboxylative reaction of quinoxalin-2(1 H )-ones with N-aryl glycines ( Scheme 1 c) [ 84 ]. Therefore, developing more g-C 3 N 4 catalyzed C3-H functionalization of quinoxalin-2(1 H )-ones is in urgent demand.…”

Visible-Light-Induced C(sp2)–C(sp3) Cross-Dehydrogenative-Coupling Reaction of N-Heterocycles with N-Alkyl-N-methylanilines under Mild Conditions

“…In 2020, Chen and Yu groups cooperatively reported a visible-light-induced addition reaction of quinoxalin-2(1H)-ones with N-aryl glycines achieving 3aminomethyl-substituted 3,4-dihydroquinoxalin-2(1H)-ones (Scheme 1, equation d). 16 This hydro-aminomethyl addition transformation features the utilization of recyclable g-C 3 the catalyst, mild conditions, and easy operation. However, compared with N-aryl glycines which have to undergo decarboxylation to generate aminomethyl radicals, N-methylaniline derivatives are regarded as more environmentally friendly and higher atom-economic aminomethyl radical precursors.…”

“…In addition, over the past decade, various protocols for the C–H functionalization of quinoxalin-2­(1 H )-ones, including alkylation, arylation, acylation, amination, alkoxylation, phosphorylation, sulfenylation, and so forth, have been accomplished, but the direct introduction of diverse aminomethyl groups into quinoxalin-2­(1 H )-ones via C–H functionalization is extremely rare. In 2020, Chen and Yu groups cooperatively reported a visible-light-induced addition reaction of quinoxalin-2­(1 H )-ones with N -aryl glycines achieving 3-aminomethyl-substituted 3,4-dihydroquinoxalin-2­(1 H )-ones (Scheme , equation d) . This hydro-aminomethyl addition transformation features the utilization of recyclable g-C 3 N 4 as the catalyst, mild conditions, and easy operation.…”