Iron catalyzed metal-ligand cooperative approaches towards sustainable synthesis of quinolines and quinazolin-4(3H)-ones

Herein we report simple, efficient, and economically affordable metal-ligand cooperative strategies for synthesizing quinolines and quinazolin-4(3H)-ones via dehydrogenative functionalization of alcohols. Various polysubstituted quinolines and quinazolin-4(3H)-ones were prepared in good yields via dehydrogenative coupling of readily available alcohols with ketones and 2-aminobenzamides, respectively under air using a well-defined Fe(II)-catalyst, ([FeL1 Cl-2] (1)) bearing a redox-active azo-aromatic pincer 2-((4-chlorophenyl)diazenyl)-1,10-phenanthroline) (L-1). Control experiments and mechanistic investigation disclose that the one-electron reduced mono-anionic species [1](-) bearing an iron-stabilized azo-anion radical ligand catalyzes these reactions. Both iron and the redox-active arylazo ligand participate synergistically during the different steps of these catalytic reactions. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study presents a metal-ligand cooperative strategy for synthesizing quinolines and quinazolin-4(3H)-ones via dehydrogenative functionalization of alcohols. Various polysubstituted quinolines and quinazolin-4(3H)-ones were prepared in good yields using an Fe(II) catalyst and a redox-active azo-aromatic pincer, showing synergistic participation of iron and the ligand during the catalytic reactions.