Cascade Reaction of α, β‐Unsaturated Ketones and 2‐Aminoaryl Alcohols for the Synthesis of 3‐Acylquinolines by a Copper Nanocatalyst

Abstract

3‐Acylquinolines possess widespread applications in functional chemicals. However, the convenient and selective synthesis of such important substructures has to date remained a challenge. Herein, we report a method to access 3‐acylquinolines from α, β‐unsaturated ketones and 2‐aminoaryl alcohols in one pot with a copper nanocatalyst supported on nitrogen‐silica‐doped carbon (Cu/N−SiO2−C). Mechanistically, the construction of the product involves a cascade procedure including radical‐type oxidation of 2‐aminoaryl alcohols, aza‐Michael addition and annulation. This developed protocol proceeds with merits of mild reaction conditions, good functional group tolerance, earth‐abundant and reusable copper catalyst, easily available stocks and O2 as the sole oxidant, which provides an alternative way for the sustainable synthesis of quinoline derivatives.

Recent Advances in the Use of 2‐Aminobenzyl Alcohols in the Synthesis of Quinolines, Quinazolines and Other N‐Heterocycles

“…[40] Meanwhile, another synthesis of quinolines 39, 40 from 2-aminobenzyl alcohols 1, 35 and enones 24 was extended (Scheme 24). [41] In this procedure, 3-acylquinolines were formed under catalysis of copper and nitrogen-silica-doped carbon (Cu/NÀ SiO 2 À C). The transformation was carried out through radical-type oxidation of 2-aminbenzyl alcohol, aza-Michael addition and annulation.…”

A Metal‐Free KOtBu‐Mediated Protocol towards the Synthesis of Quinolines, Indenoquinolines and Acridines

“…[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] The transition-metal catalyzed dehydrogenative coupling reactions were extensively studied for the synthesis of quinolines by employing 2-aminoarylmethanols and ketones/secondary alcohols. [7][8][9][10][11][12][13][14] The transition-metals such as Ru, Ir, Cu, Mn, Co, Ni were utilized for accomplishing the synthesis of quinoline derivatives. In recent years, metal-free approaches have also been investigated for the synthesis of quinolines by using 2-aminoarylmethanols as precursors.…”

“…To address these concerns, sustainable and atom‐economical methodologies were investigated towards the synthesis of diverse quinolines. In the past decades, the synthesis of quinolines was largely realized using 2‐aminoarylmethanols or 2‐aminoaryl carbaldehydes/2‐aminoaryl ketones in combination with ketones/secondary alcohols as precursors [7–21] . The transition‐metal catalyzed dehydrogenative coupling reactions were extensively studied for the synthesis of quinolines by employing 2‐aminoarylmethanols and ketones/secondary alcohols [7–14] …”

“…In the past decades, the synthesis of quinolines was largely realized using 2-aminoarylmethanols or 2aminoaryl carbaldehydes/2-aminoaryl ketones in combination with ketones/secondary alcohols as precursors. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] The transition-metal catalyzed dehydrogenative coupling reactions were extensively studied for the synthesis of quinolines by employing 2-aminoarylmethanols and ketones/secondary alcohols. [7][8][9][10][11][12][13][14] The transition-metals such as Ru, Ir, Cu, Mn, Co, Ni were utilized for accomplishing the synthesis of quinoline derivatives.…”

Lewis acid-mediated modular route to the synthesis of 3-substituted quinolines from 2-aminobenzyl alcohols and enamine(one)s

“…The 2-aminobenzyl alcohols have been demonstrated to be aldehyde surrogates; therefore, Xiong et al reported the synthesis of 2-substituted-3-acylquinolines via the reaction between 2-aminobenzyl alcohols and α,β-unsaturated ketones in the presence of a copper catalyst and additives. 25 Subsequently, Yu et al demonstrated the synthesis of 3-aroylquinolines via the direct oxidative cyclocondensation of N , N ′-dimethyl enaminones with 2-aminobenzyl alcohols in the presence of potassium persulfate. 26 John et al described a [4+2] Diels Alder cycloaddition route toward 3-aroyl quinolines from enaminones and generated aza- o -quinone methides from 2-aminobenzyl chloride in situ .…”