Palladium(II)-Catalyzed Oxidative Arylation of Quinoxalin-2(1H)-ones with Arylboronic Acids

Abstract

A straightforward palladium-catalyzed oxidative C-3 arylation of quinoxalin-2(1H)-ones with arylboronic acids is reported. This protocol is compatible with a wide range of functional groups and allows construction of various biologically important quinoxalin-2(1H)-one backbones.

Electrosynthesis of C3 Alkoxylated Quinoxalin‐2(1H)‐ones through Dehydrogenative C–H/O–H Cross‐Coupling

“…Electrocatalysis was conducted by using a DC‐power supplier DP3005B in constant current mode, CV studies were performed using a CHI600E workstation. The substituted quinoxalin‐2(1 H )‐ones ( 1a – 1h , 1j – 1q and 1s – 1u ) were prepared according to the literature reports …”

Photocatalyst‐free Photoredox Arylation of Quinoxalin‐2(1H)‐Ones with Aryldiazo Sulfones

“…: 120–125°C [Ref. , 128–130°C]; 1 H NMR (400 MHz, CDCl 3 ): δ 8.37 (d, J = 9.0 Hz, 2H), 7.91 (d, J = 7.8 Hz, 1H), 7.52 (td, J = 8.4, 1.2 Hz, 1H), 7.37–7.30 (m, 2H), 6.99 (d, J = 9.0 Hz, 2H), 3.88(s, 3H), 3.76 (s, 3H); 13 C NMR (100 MHz, CDCl 3 ): δ 161.4, 154.8, 153.2, 133.2, 133.1, 131.3, 130.1, 129.7, 128.6, 123.6, 113.4, 55.3, 29.2; EI‐MS: m/z = 266.1 [M + ].…”

“…: 160–163°C [Ref. , 162–164°C]; 1 H NMR (400 MHz, CDCl 3 ) δ 8.42–8.38 (m, 2H), 7.95 (dd, J = 7.8, 1.4 Hz), 7.49–7.45 (m, 3H), 7.36–7.27 (m, 7H), 5.57 (s, 2H); 13 C NMR (100 MHz, CDCl 3 ) δ 154.7, 152.7, 136.7, 135.2, 134.4, 133.3, 132.8, 131.1, 130.6, 130.6, 128.8, 128.3, 127.8, 126.9, 124.0, 114.4, 46.2; EI‐MS: m/z = 346.1 [M + ].…”

“…Therefore, the construction of 3‐arylquinoxalin‐2(1 H )‐one derivatives is of great significance. Several groups reported the synthesis of 3‐arylquinoxalin‐2(1 H )‐one derivatives based on CH arylation with aryl radical sources such as arylboronic acids, diaryliodonium salts, arylhydrazine/iodosobenzene, and aniline/alkyl nitrite . Although these are to some extent satisfied as synthetic process, a new and efficient arylation of 3‐quinoxalin‐2(1 H )‐ones is highly desired.…”

Sequential decarboxylative azide–alkyne cycloaddition and dehydrogenative coupling reactions: one-pot synthesis of polycyclic fused triazoles

“…Formally, it requires insertion of a transition metal (usually Pd, Ru, Rh or Ir) across a strong C–H bond (90–105 kcal/mol) to form a new, weaker C–M bond (50–80 kcal/mol), followed by generation of a new C–C bond. Generally, transition metal-catalyzed sp 2 C–H activation is facilitated by directing groups [ 10 – 13 ] or heteroatoms in the heterocyclic compounds [ 14 – 18 ]. This methodology has been applied in the synthesis of polycyclic frameworks as well as in the preparation of biologically important compounds [ 19 – 23 ].…”