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The SN2 reaction between a Grignard reagent and an epoxide
Chapter 14, Problem 14.61(choose chapter or problem)
The SN2 reaction between a Grignard reagent and an epoxide works reasonably well when the epoxide is ethylene oxide. However, when the epoxide is substituted with groups that provide steric hindrance, a competing reaction can dominate, in which an allylic alcohol is produced. Propose a mechanism for this transformation and use the principles discussed in Section 8.13 to justify why the allylic alcohol would be the major product in this case below. O OH Major product 1) EtMgBr 2) H2O HO Et Minor product
Questions & Answers
QUESTION:
The SN2 reaction between a Grignard reagent and an epoxide works reasonably well when the epoxide is ethylene oxide. However, when the epoxide is substituted with groups that provide steric hindrance, a competing reaction can dominate, in which an allylic alcohol is produced. Propose a mechanism for this transformation and use the principles discussed in Section 8.13 to justify why the allylic alcohol would be the major product in this case below. O OH Major product 1) EtMgBr 2) H2O HO Et Minor product
ANSWER:Step 1 of 3
In this problem we're told that the reaction between a Grignard reagent and an epoxide works reasonably well when the epoxide is ethylene oxide. However, a sterically-hindered epoxide leads to a competing reaction in which an allylic alcohol is produced.
We're asked to propose a mechanism for this transformation and to explain why the allylic alcohol shown is the reaction's major product.