Ether cleavage
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Ether cleavage refers to chemical substitution reactions that lead to the cleavage of ethers. Due to the high chemical stability of ethers, the cleavage of the C-O bond is uncommon in the absence of specialized reagents or under extreme conditions.[1][2]
In organic chemistry, ether cleavage is an acid catalyzed nucleophilic substitution reaction. Depending on the specific ether, cleavage can follow either SN1 or SN2 mechanisms. Distinguishing between both mechanisms requires consideration of inductive and mesomeric effects that could stabilize or destabilize a potential carbocation in the SN1 pathway. Usage of hydrohalic acids takes advantage of the fact that these agents are able to protonate the ether oxygen atom and also provide a halide anion as a suitable nucleophile. However, as ethers show similar basicity as alcohols (pKa of approximately 16), the equilibrium of protonation lies on the side of the unprotonated ether and cleavage is usually very slow at room temperature.
Ethers can be cleaved by strongly basic agents, e.g. organolithium compounds. Cyclic ethers are especially susceptible to cleavage, but acyclic ethers can be cleaved as well.