Visible-Light-Induced Synthesis of 3-Alkyl Chromones under Catalyst- and Additive-Free Conditions

Abstract

Herein, we reported an efficient and facile visible-light-induced 3-alkyl chromone synthesis from easily accessible o–hydroxyaryl enaminones and α–diazo esters. In this protocol, excellent yields were obtained with a broad substrate scope at room temperature, tolerating various functional groups. Of note is that this eco-friendly methodology features catalyst- and additive-free, mild reaction conditions, simple operation procedure, and easy scale-up, which affords a convenient pathway for the preparation of 3-alkyl chromones. Experimental results and density functional theory (DFT) computation analyses confirm the participation of carbene species and active cyclopropane intermediate.

Visible Light Mediated Synthesis of 3‐Indolmethyl Chromones via the Cyclization of o‐Hydroxyaryl Enaminones with 3‐Indoleacetic Acids Catalyzed by Graphitic Carbon Nitride Adorned with Copper Nanoparticles

“…[14][15][16][17] The incorporation of the indolmethyl moiety is of immense interest in organic chemistry due to its prevalence in various pharmaceuticals and natural products. [18][19][20][21][22] One promising approach for introducing this portion involves decarboxylative transformations of carboxylic acids. [23,24] Chromones are equally important compounds found in nature and pharmaceuticals, that serve as key building blocks for the synthesis of heterocyclic molecules; [25,26] their functionalization through CÀ H bond activation being a valuable strategy.…”