Acid Cleavage of Ethers

Ethers are generally unreactive to most species. With strong acid, however, ethers undergo a cleavage through a process begun by protonation of the ether oxygen. HI and HBr are often used. The products separate in either an SN1 or SN2 style process, determined by the shape of the ether, the halide anion serving as nucleophile. Some of E1ís alkene product, as always, will be mixed in if SN1 occurs.