# Heterocycle compounds synthesized by amide ligand-promoted copper salt catalyzed construction of C–O(S) bonds

## TL;DR

A new copper-catalyzed method efficiently builds six-membered rings containing oxygen or sulfur from 2-halophenol.

## Contribution

A mild and scalable copper-amide catalytic system for constructing C–O(S) bonds and six-membered heterocycles.

## Key findings

- The copper-amide system enables efficient coupling and cyclization of 2-halophenol.
- The method works with both 2-bromophenol and less reactive 2-chlorophenol.
- Gram-scale reactions confirm the process is operationally simple and scalable.

## Abstract

We introduce a mild method for the ligand-promoted copper-catalyzed coupling of 2-halophenol to construct DBDO using cost-effective copper salts, ligands, and alkaline reagents. This method cleverly makes 2-bromophenol complete the Ullman reaction twice, achieves efficient C–O(S) bond coupling and intermolecular cyclization, and yields high amounts of oxygen(sulfur)-containing six-membered ring products. Less reactive 2-chlorophenol was also applied in this catalytic system. The application range of the copper-amide catalytic system was further expanded. Moreover, the success of a gram-scale reaction demonstrated that this operationally simple process is scalable.

We introduce a mild method for the ligand-promoted copper-catalyzed coupling of 2-halophenol to construct DBDO using cost-effective copper salts, ligands, and alkaline reagents.