Carbocatalytic Cascade Synthesis of Polysubstituted Quinolines from Aldehydes and 2‐Vinyl Anilines

Abstract

Oxidized active carbon (oAC) catalyses the formation of polysubstituted quinolines from o‐vinyl anilines and aldehydes. The reaction proceeds in a cascade manner through condensation, electrocyclization and dehydrogenation, and gives access to a wide range of quinolines with alkyl and/or aryl substituents as demonstrated with 40 examples. The metal‐free catalytic procedure allows a heterogeneous protocol for the synthesis of various polysubstituted quinolines. The mechanistic studies imply that both the acid and quinoidic groups in oAC are integral for the catalytic manifold.

Carbon Materials as Catalytic Tools for Oxidative Dehydrogenations and Couplings in Liquid Phase

“…The reaction scope was studied extensively and the synthesis of forty different polysubstituted quinolines was reported with isolated yields of up to 99%. 42 In both this and the previous study (Schemes 12 and 13), the catalytic activity was associated with the C=O content of the carbon material, determined by XPS, and the ac-tive sites were proposed to be of quinoidic nature by molecular model compound tests and surface group blocking on the carbon catalyst. 42 Moreover, the mechanism was explored through both experimental kinetic studies and DFT calculations with o-benzoquinone and PQ as computational models for the carbocatalysts.…”

“…The reaction scope was studied extensively and the synthesis of forty different polysubstituted quinolines was reported with isolated yields of up to 99%. 42…”

Synthesis of 2,3‐Disubstituted Quinoline‐4‐carbonitriles through Truce–Smiles Rearrangement of Phenacyl‐4‐nitrobenzenesulfonamides

“…In the past five years, there has been an increased interest in the synthesis of 2,3-diarylquinolines and different strategies were reported using mostly transition-metal catalysis (Figure 2). [7][8][9][10][11][12][13] In contrast, a single reported method, based on the cyclization of cis-chalcones, [14] is available for preparing of the 2,3-diarylquinoline-4-carbonitriles. Importantly, 2,3-diarylquinolines have remarkable biological properties and are antituberculotic, [15,16] antibacterial, [17,18] antiproliferative [19] and anti-inflammatory agents.…”

“…Some previously reported approaches to 2,3-diarylquinoines. [7][8][9][10][11][12][13][14] www.eurjoc.org…”

Phenanthrenequinone-Sensitized Photocatalytic Synthesis of Polysubstituted Quinolines from 2-Vinylarylimines

“…This scenario was further supported by our previous DFT computational results, which predicted low energy barriers for the radical-cation-mediated cyclization route of 2-vinylarylimines to dihydroquinolines. 12 …”