What is the major difference in the structure of the product formed in a Grignard reaction when an alkyl magnesium halide (Grignard reagent) is reacted with an epoxide rather than an aldehyde or ketone followed by work-up with H₃O⁺?

Question

Quizplus · Accepted Answer

When an alkyl magnesium halide reacts with an epoxide, the alkyl group will bond to the β-carbon of the alcohol product. This is because the epoxide ring is opened by nucleophilic attack at the less hindered carbon, which is the β-carbon in this case. On the other hand, when an aldehyde or ketone is reacted with a Grignard reagent followed by work-up with water and acid, the resulting product is an alcohol with the alkyl group bonded to the α-carbon. This difference in structure is due to the difference in the reaction conditions and mechanisms.

What Is the Major Difference in the Structure of the Product