| 
          
          
             Williamson synthesis of acyclic ethers 
            (you cannot add a tertiary halide in the second step)  | 
          
          
             
             | 
          
          
             Cleavage of methyl ethers with HI  | 
          
          
             
             | 
          
          
             Nucleophilic ring opening of epoxides (oxiranes)  | 
          
          
             
             | 
          
          
             Acid-catalyzed ring opening of epoxides (oxiranes)  | 
          
          
             
             | 
          
          
             Nucleophilic ring opening of epoxides (oxiranes)  | 
          
          
             
             |