Reactions of Ethers
Ethers (R-O-R’) are compounds formed by replacing hydrogen atoms of an alcohol (R-OH compound) or a phenol (C6H5OH) by an aryl/ acyl group (functional group after removing single hydrogen from an aromatic ring). In this section, reaction, preparation and behavior of ethers are discussed in the context of organic chemistry.
Epoxides
Epoxides are a special class of cyclic ethers which are an important functional group in organic chemistry and generate reactive centers due to their unusual high reactivity. Due to their high reactivity, epoxides are considered to be toxic and mutagenic.
Williamson Ether Synthesis
An organic reaction in which an organohalide and a deprotonated alcohol forms ether is known as Williamson ether synthesis. Alexander Williamson developed the Williamson ether synthesis in 1850. The formation of ether in this synthesis is an SN2 reaction.
![**Question 24**
**Assign the alkene stereochemistry as E or Z.**
[Image: Molecular structure with a double bond between two carbons, one carbon attached to a chlorine atom (Cl) and the other carbon attached to an ethyl group.]
- ☐ E
- ☐ Z
**Explanation:**
To determine the stereochemistry of the alkene as E or Z, you need to evaluate the priority of the substituents attached to the double-bonded carbons according to the Cahn-Ingold-Prelog priority rules.
1. Identify the two substituents attached to each carbon of the double bond.
2. Assign priorities to the substituents on each carbon based on atomic number. Higher atomic numbers receive higher priority.
3. Compare the positions of the highest priority substituents on each carbon:
- If the highest priority substituents are on the same side of the double bond, the configuration is Z (from German "zusammen" meaning together).
- If the highest priority substituents are on opposite sides of the double bond, the configuration is E (from German "entgegen" meaning opposite).
Analyzing the given structure:
- For the left carbon of the double bond, the substituents are a chlorine atom (Cl) and a hydrogen atom (not shown but implied).
- For the right carbon of the double bond, the substituents are an ethyl group (C2H5) and a hydrogen atom (not shown but implied).
According to atomic numbers:
- Chlorine (Cl) has a higher atomic number than hydrogen (H).
- The ethyl group (C2H5) has a higher priority than hydrogen (H) due to the carbon atoms being of higher atomic number than hydrogen.
Since chlorine (the highest priority substituent on the left carbon) and the ethyl group (the highest priority substituent on the right carbon) are on opposite sides of the double bond, the alkene has an E configuration.
Thus, select "E" for the correct answer.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fd4844e47-8bac-47db-9d5f-a634c5eb0fa3%2Fe7bd1892-239a-4b3f-9c55-ad3373dbe1af%2F8y9kh8o_processed.jpeg&w=3840&q=75)

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