Chemistry - ALCOHOL & ETHER Question with Solution | TestHub
Due to severe angle strain, epoxides undergo ring opening reactions readily. In the presence of an acid
catalyst, such as sulfuric acid, epoxides are hydrolyzed to glycols. Because there is some carbocation
character developed in the transition state for an acid-catalyzed epoxide ring opening, attack of the
nucleophile on unsymmetrical epoxides occurs preferentially at the carbon better able to bear a partial
positive charge. Epoxides undergo ring-opening reactions with a variety of nucleophiles. Good nucleophiles attack an epoxide ring by an SN2 mechanism and show an SN2 -like regioselectivity; that is, the nucleophile attacks at the less hindered carbon.
The product of the following reaction is
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Answer:
Solution:
Explain Question:
To identify the product formed by nucleophilic attack on given cyclic ether.
Concept:
This question is based on nucleophilic substitution reaction on epoxide
Solution:
The reaction shown is the acid-catalyzed ring-opening of an epoxide (propylene oxide) by an alcohol
(ethanol).
Under acidic conditions (H+ ), the epoxide oxygen is protonated first.
The ring-opening is an SN1-like process where the nucleophile attacks the more substituted
carbon.
The product formed from the attack at the more substituted carbon is 2-ethoxy-1-propanol, which
is the major product under these conditions.
