Activated‐Carbon‐Supported Calcium Oxide: A Selective and Efficient Catalyst for Nitrile‐Containing Diaryl Ether Synthesis

Abstract Activated‐carbon‐supported calcium oxide (CaO@AC) was prepared from AC and a suspension derived from CaO and ammonium carbonate. After calcination under nitrogen, high purity CaO@AC was obtained. The nature of non‐aggregation and high purity of CaO@AC enabled a clean and selective synthesis protocol for nitrile‐containing diaryl ethers. Various functional groups including methoxyl, amino, carboxyl, allyl and nitro were well‐tolerated, and products were obtained in excellent yields and purities. Asymmetric substitutions could be achieved via simple adjustment of reaction conditions, and transetherification was greatly suppressed to 10 −3 –10 −4 scale. In addition, a mechanism for suppression in transetherification was proposed and discussed.