Question

What product would you expect from cleavage of tetrahydrofuran

with HI?

Short answer

The expected product from cleavage of tetrahydrofuran with HI is shown below:

Tetrahydrofuran4-iodobutan-1-ol

Step-by-step solution

Acidic Ether cleavages  reaction

Acidic ether cleavages are typical nucleophilic substitution reactions and take place by either ${\mathbf{S}}_{\mathbf{N}}\mathbf{1}$or${\mathbf{S}}_{\mathbf{N}}\mathbf{2}$mechanisms, depending on the structure of the substrate. Ethers with only primary and secondary alkyl groups react by an ${\text{S}}_{N}2$mechanism, in which ${\text{I}}_2$or${\text{Br}}_2$ attacks the protonated ether at the less hindered site. This usually results in a selective cleavage into a single alcohol and a single alkyl halide. For example, ethyl isopropyl ether exclusively yields isopropyl alcohol and iodoethane on cleavage by HI.

Identify the product of the given reaction

Tetrahydrofuran reacts with hydrogen iodide HI, in the aqueous medium to form 4-iodobutan-1-ol and ethyliodide. Tetrahydrofuran is cyclic ether which is sensitive towards strong acid like hydrogen iodide (HI). In the presence of aqueous solution we get the desired product as shown below:

Tetrahydrofuran4-iodobutan-1-ol