Textbook Question
What are the products of the following reactions? Show all stereoisomers that are formed.
a.
b.
718
views
13. Alcohols and Carbonyl Compounds
Organometallic Cumulative Practice
1:39 minutesProblem 8b
Textbook Question
What alcohols are formed from the reaction of ethylene oxide with the following organocuprates followed by the addition of acid?
b. (CH3CH=CH)2CuLi
Verified step by step guidance1
Step 1: Understand the reaction mechanism. Ethylene oxide reacts with organocuprates (R2CuLi) via nucleophilic attack. The organocuprate acts as a nucleophile, attacking the less sterically hindered carbon of the ethylene oxide ring, leading to ring opening.
Step 2: Identify the nucleophile in the given organocuprate. The organocuprate provided is (CH3CH=CH)2CuLi, which contains two allyl groups (CH3CH=CH). These allyl groups are the nucleophilic species that will attack the ethylene oxide.
Step 3: Predict the product of the nucleophilic attack. One of the allyl groups (CH3CH=CH) will attack the less hindered carbon of the ethylene oxide, breaking the three-membered ring and forming a new C-C bond. This results in an intermediate alkoxide.
Step 4: Consider the role of acid in the reaction. After the nucleophilic attack, the intermediate alkoxide is protonated by the addition of acid (e.g., H3O+), converting the alkoxide into an alcohol.
Step 5: Write the structure of the final product. The final product will be an alcohol where the allyl group (CH3CH=CH) is attached to one of the carbons of the ethylene oxide, and the other carbon of the ethylene oxide becomes part of the hydroxyl (-OH) group.
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Video duration:
1mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Ethylene Oxide Reactivity
Ethylene oxide is a cyclic ether that reacts with nucleophiles due to its strained ring structure. When it undergoes ring-opening reactions, it can form alcohols. The nucleophile attacks the less hindered carbon atom, leading to the formation of a primary alcohol after subsequent protonation.
Recommended video:
Guided course
03:51
Reagents used to oxidize Sulfides.
Organocuprates
Organocuprates, such as (CH3CH=CH)2CuLi, are organometallic compounds that act as nucleophiles in organic reactions. They are derived from lithium diorganocopper reagents and are known for their ability to add to electrophiles, such as carbonyls or epoxides, facilitating the formation of new carbon-carbon bonds.
Acid-Catalyzed Protonation
After the nucleophilic attack on ethylene oxide, the resulting alkoxide intermediate can be protonated by an acid. This step is crucial as it converts the alkoxide into a stable alcohol. The choice of acid can influence the reaction's efficiency and the final product's structure.
Recommended video:
Guided course
03:09Acid Catalyzed
Related Videos
Related Practice