Organic Chemistry - Elimination/substitution

In summary, the problem at hand involves using TsOH to replace -OH groups with TsO, resulting in an E1cb reaction. The desired product is an alkene, but the question is how to obtain it. It is suggested to use Et3N as a base to abstract H and form the alkene. However, the mechanism drawn does not provide a solution. It is then mentioned that Compound A would react with LDA to form an alkyne. This is an E1cb reaction and the formation of the alkyne is expected. The suggested structures and reactions involve CH3SO2Cl as a good substitution for OH and Et3N as a good base.
  • #1
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Homework Statement


I have this problem:
I known that reaction with TsOH would replace -OH groups with TsO (substitution reaction). (Et)3N would therefore act as a base to abstract H to form an alkene. The problem is i know it should be an E1cb reaction but how do I obtain an alkene? I tried to draw the mechanism but comes to no solution can anyone help or am i in the wrong direction?
Compound A would then react with LDA - which I guess is to form alkyne so A should be an alkene) or am I worng?
Thank you!

Homework Equations


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CH3SO2Cl is a good substitution for OH. Et3N is a good base.

The Attempt at a Solution


(See part 1) Would the compound form be this: I guess not since the compound is relatively unstable
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  • #2
.CH3SO2Cl + Et3N -> CH3SO2- + Et3NH+ Then the reaction of CH3SO2- with LDA would then form an alkyne. The structure would look like this: CH3SO2- + LDA -> CH3SO2-LDAThis is an E1cb reaction and the formation of the alkyne should be the result.
 

FAQ: Organic Chemistry - Elimination/substitution

1. What is the difference between elimination and substitution reactions in organic chemistry?

Elimination reactions involve the removal of a small molecule, such as a hydrogen atom or a halogen, from a molecule to form a double or triple bond. Substitution reactions, on the other hand, involve the replacement of an atom or group of atoms in a molecule with another atom or group of atoms. In elimination reactions, the starting molecule and the product have the same number of atoms, while in substitution reactions, there is a change in the number of atoms in the product.

2. What factors influence the rate of elimination and substitution reactions?

The rate of elimination and substitution reactions can be influenced by several factors, including the nature of the substrate, the strength of the nucleophile or base, the steric hindrance of the substrate, and the solvent used. Additionally, the presence of substituents on the substrate can also affect the rate of these reactions.

3. How do you predict the products of elimination and substitution reactions?

To predict the products of elimination and substitution reactions, it is important to understand the mechanisms of these reactions. Elimination reactions typically follow either the E1 or E2 mechanism, while substitution reactions can follow either the SN1 or SN2 mechanism. By considering the properties of the substrate and the strength of the nucleophile or base, as well as the reaction conditions, it is possible to predict the major product of these reactions.

4. Can elimination and substitution reactions occur simultaneously?

Yes, it is possible for elimination and substitution reactions to occur simultaneously. This is known as a competition reaction, where both elimination and substitution products are formed. The product that is favored will depend on the reaction conditions and the relative rates of the competing reactions.

5. How are elimination and substitution reactions used in the synthesis of organic compounds?

Elimination and substitution reactions are important tools in the synthesis of organic compounds. These reactions can be used to introduce new functional groups or modify existing ones. By carefully selecting the reaction conditions and controlling the regio- and stereochemistry, chemists can design efficient synthetic routes to produce a wide range of organic compounds.

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