Cs2 CO3 -Promoted C-O Coupling Protocol Enables Solventless (Hetero)aryl Ether Synthesis under Air Atmosphere

Abstract

In this work, a Cs₂ CO₃ -promoted synthetic approach was identified for (hetero)aryl ether synthesis via the C-O coupling of various (hetero)aryl chlorides and alcohols/phenol. To our delight, the reactions could be carried out under transition-metal-free and solvent-free conditions. Moreover, analytical-grade reagents and air atmosphere were readily tolerated. To showcase the practical usefulness of the present protocol, the assembly of a bioactive molecule was facilely realized and the gram-scale production of selected ether products was also efficiently accomplished. In addition, density functional theory (DFT) studies, along with a few mechanistic experiments, were conducted to elucidate a proposed reaction pathway and rationalize the pivotal role of Cs₂ CO₃ in promoting this process. Hopefully, this work could provide useful information for researchers who are engaging in C-O cross-coupling reactions.

Keywords: Cesium carbonate (Cs2CO3); C−O coupling; air atmosphere; density functional theory (DFT); solvent-free; transition-metal-free.