Allylic and benzylic alcohols are converted into the symmetrical ethers in the presence of zinc chloride in dichloroethane. Secondary benzylic alcohols like sec-phenethyl alcohol react with primary alcohols and allylic alcohols to give the corresponding unsymmetrical ethers in good yields under the present conditions.
Also, activated 1,n-diols are cyclodehydrated with zinc chloride to give ethenyl or aromatic group substituted 5- or 6-membered cyclic ethers in excellent yields.
Of synthetic significance is the direct conversion of alcohols into ethers under very mild and essentially neutral conditions.