Expedient synthesis of pyrrolo[1,2-a]quinoxalines through one-pot three-component reactions of o-phenylenediamines, 2-alkoxy-2,3-dihydrofurans and ketones

Three-component reactions of aromatic amines, 1,3-dicarbonyl compounds, and α-bromoacetaldehyde acetal to access N-(hetero)aryl-4,5-unsubstituted pyrroles

N-(Hetero)aryl-4,5-unsubstituted pyrroles were synthesized from (hetero)arylamines, 1,3-dicarbonyl compounds, and α-bromoacetaldehyde acetal by using aluminum(III) chloride as a Lewis acid catalyst through [1 + 2 + 2] annulation. This new versatile methodology provides a wide scope for the synthesis of different functional N-(hetero)aryl-4,5-unsubstituted pyrrole scaffolds, which can be further derived to access multisubstituted pyrrole-3-carboxamides. In the presence of 1.2 equiv of KI, a polysubstituted pyrazolo[3,4-b]pyridine derivative was also successfully synthesized.

α-Hydroxy acid as an aldehyde surrogate: metal-free synthesis of pyrrolo[1,2-a]quinoxalines, quinazolinones, and other N-heterocycles via decarboxylative oxidative annulation reaction

A metal-free and efficient procedure for the synthesis of pyrrolo[1,2-a]quinoxalines, quinazolinones, and indolo[1,2-a]quinoxaline has been developed. The key features of our method include the in situ generation of aldehyde from α-hydroxy acid in the presence of TBHP (tert-butyl hydrogen peroxide), and further condensation with various amines, followed by intramolecular cyclization and subsequent oxidation to afford the corresponding quinoxalines, quinazolinones derivatives in moderate to high yields.

4-Aminoindoles as 1,4-bisnucleophiles for diversity-oriented synthesis of tricyclic indoles bearing 3,4-fused seven-membered rings

A straightforward access to tricyclic indoles bearing 3,4-fused seven-membered rings was established by using 4-aminoindoles as 1,4-bisnucleophiles in three-component reactions.

A diversity-oriented synthesis of cyclopenta[b]pyrroles and related compounds through a calcium(ii)/copper(ii) catalytic sequence

A sequential bicatalytic route relying on calcium(ii) and copper(ii) salts is described to provide access to original nitrogen-containing heterocycles.

Synthesis of pyrrolo[1,2-a]quinoxalines via copper or iron-catalyzed aerobic oxidative carboamination of sp3C–H bonds

We developed an aerobic oxidative carboamination of sp³C–H bonds with 2-(1H-pyrrol-1-yl)anilines for synthesis of pyrrolo[1,2-a]quinoxalines.