# Mild Iron-Catalyzed Oxidative Cross-Coupling of Quinoxalinones with Indoles

## TL;DR

A new iron-catalyzed method efficiently couples quinoxalinones and indoles to form useful derivatives under mild conditions.

## Contribution

A mild, scalable, and cost-effective iron-catalyzed oxidative cross-coupling method for synthesizing 3-(indol-3-yl)quinoxalin-2-one derivatives.

## Key findings

- The method allows incorporation of diverse functional groups into the final products.
- The reaction can be scaled up to gram-scale with high yields.
- Iron chloride facilitates key intermediates that undergo oxidation to form the products.

## Abstract

Utilizing iron chloride as a Lewis acid catalyst, we developed a straightforward and mild oxidative cross-coupling reaction between quinoxalinones and indoles, yielding a series of versatile 3-(indol-3-yl)quinoxalin-2-one derivatives. This approach allows for the incorporation of a wide array of functional groups into the final products, demonstrating its synthetic versatility. Notably, the method was successfully scaled up to gram-scale reactions while maintaining high yields. Our mechanistic investigation indicates that iron chloride serves as a catalyst to facilitate the formation of key intermediates which subsequently undergo oxidation to afford the desired products. The merits of this protocol include its cost effectiveness, operational simplicity, and the ease of product isolation via filtration.