Synthesis 2023; 55(24): 4191-4203
DOI: 10.1055/s-0042-1751489
paper

Oxidative Cyclization Reactions Catalyzed by Designed Transition-Metal Complexes: A New Strategy for the Synthesis of Flavone, Quinolone, and Benzofuran Derivatives

a   Department of Chemistry, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
,
Sain Singh
a   Department of Chemistry, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
,
Kaushik Ghosh
a   Department of Chemistry, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
b   Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
,
Naseem Ahmed
a   Department of Chemistry, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
› Author Affiliations


Abstract

An efficient and convenient synthetic protocol is reported for the synthesis of 2-phenyl-4H-chromen-4-one, 2-phenylquinolin-4(1H)-one, and 11H-benzofuro[3,2-b]chromen-11-one derivatives from 2′-hydroxychalcones, 2′-aminochalcones, and 3-hydroxyflavones, respectively, using transition-metal catalysts and TEMPO as an oxidizing agent. This catalytic heterocyclization approach involves in situ free-radical generation as phenoxyl radicals were detected by EPR spectroscopic study and H2O2 was formed. The present method has numerous advantages, such as high atom-economy, less hazardous synthesis, benign solvent and auxiliaries, easy handling, and broader substrate scope with good to excellent product yields.

Supporting Information



Publication History

Received: 06 July 2023

Accepted after revision: 09 August 2023

Article published online:
26 September 2023

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