Catalyst-free Synthesis Of Diaryl Ethers And Alkyl Aryl Ethers From Aryl Sulfonates

Alkyl aryl ethers and diaryl ethers are important building blocks and intermediates,which are generally used in pharmaceutical compounds,natural products,pesticide and materials.The synthesis of alkyl aryl ethers from aryl sulfonates with alcohol,or from alkyl tosylates with phenol without catalysts is described.Diaryl ethers prepared by using phenyl o-nitrobenzenesulphonate and corresponding phenol are also reported.The optimum reaction conditions are discovered for the two reaction systems respectively.For the reactions between aryl sulfonates and alcohols,the optimal reaction conditions were:2 equiv.K2CO3 in 0.5 mL alcohol used as the reactant as well as the solvent at 65 ?.4-Nitrophenylethylether as the model product was achieved with the yield of 86%.The substrate scope investigation showed that the reactions of nitrophenyl benzenesulfonates with a varity of alcohol obtained medium to good yields except for isopropanol which was barely reacted.And this protocol also worked well with the reactions between alkyl tosylates and phenols.Phenols with both electron-donating and electron-withdrawing groups could reacted smoothly with alkyl tosylates with medium to good yields.The optimum reaction conditions for the reaction between o-nitrobenzenesulphonate and phenol were:3 equiv.K3PO4 in lmL toluene at 100?.Electron-donating substituents and steric hindrance phenols were tolerated with medium yields.However,phenyl o-nitrobenzenesulphonate was found to give 1-nitro-2-phenoxybenzene without phenol,although with a relatively lower yield.O-nitrobenzenesulphonates with different functional groups were used to react with the corresponding phenols in order to avoid the undesired product,1-nitro-2-phenoxybenzene,which was produced by o-nitrobenzenesulphonates.