Chemistry - ALCOHOL & ETHER Question with Solution | TestHub

Question Explanation:

To find the product of cleavage of given unsymmetrical cyclic ether by HI (1 equivalent).

Concept:

Question is asking about acidic cleavage of cyclic ether with HI.

Solution:

The reaction involves the acidic cleavage of a cyclic ether (a tetrahydrofuran derivative) using a limited amount (1 equivalent) of HI .

Protonation:

The ether oxygen is first protonated by HI, forming a cyclic oxonium ion.

1. Cyclic Ether + HI → Protonated Oxonium Ion + I⁻

2. Ring Opening (S_N1 Pathway):  Due to the presence of a tertiary alkyl group, the protonated ether N N undergoes cleavage via an S_N1 mechanism. The O–C bond breaks to generate the more stable tertiary carbocation, while the I^- ion attacks this carbocation.

Because only one equivalent of HI is present, the reaction proceeds selectively, producing an iodo alcohol.