How a alkyne will react with a ketone

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In summary, the reaction between an alkyne and a ketone can result in the formation of enones, dienones, or vinyl ketones depending on the reaction conditions and specific reactants used. The mechanism typically involves an acid-catalyzed addition reaction, and the reactivity can be influenced by the substituent on the alkyne. Both terminal and internal alkynes can react with ketones, with terminal alkynes being generally more reactive. These reactions have various applications in organic synthesis, including the construction of new carbon-carbon bonds and the introduction of functional groups for further modification. They are also commonly used in natural product synthesis and pharmaceutical development.
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bjon-07
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Can some one send me link that shows how a alkyne will react with a ketone. I have tryed google but found nothing.
 
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  • #2
Well you'll probably need to treat the alkyne with NaNH2 first, in order for it to react as a nucleophile towards the ketone. Otherwise, I'm not aware of any particular reactions of an alkyne in general and a ketone.
 
  • #3
We reacted tetraphenylcyclopentadiene with diphenylacetylene while heating with a blow torch in silicone oil. Thats it, there where no bases
 

Related to How a alkyne will react with a ketone

1. What products are formed when an alkyne reacts with a ketone?

The products formed depend on the reaction conditions and the specific alkyne and ketone used. In general, the reaction will result in the formation of a new carbon-carbon bond, with the alkyne acting as a nucleophile and the ketone as an electrophile. This can result in the formation of an enone, a dienone, or a vinyl ketone.

2. What is the mechanism for the reaction between an alkyne and a ketone?

The reaction between an alkyne and a ketone typically proceeds through an acid-catalyzed addition reaction. The alkyne first protonates to form a more reactive carbocation, which then attacks the electrophilic carbonyl carbon of the ketone. This is followed by deprotonation and rearrangement to form the final product.

3. How does the substituent on the alkyne affect the reactivity in the reaction with a ketone?

The nature of the substituent on the alkyne can greatly influence the reactivity in the reaction with a ketone. Electron-withdrawing groups on the alkyne, such as a halogen or nitro group, can enhance the reactivity by stabilizing the intermediate carbocation. On the other hand, electron-donating groups, like an alkyl or aryl group, can decrease the reactivity by destabilizing the carbocation intermediate.

4. Can a ketone react with both terminal and internal alkynes?

Yes, a ketone can react with both terminal and internal alkynes. However, the reactivity may differ depending on the type of alkyne. Terminal alkynes are generally more reactive due to the presence of a more accessible and reactive sp carbon. Internal alkynes may require harsher reaction conditions or the use of a more reactive ketone to undergo the addition reaction.

5. What are the applications of alkyne-ketone reactions in organic synthesis?

Alkyne-ketone reactions are commonly used in organic synthesis for the construction of new carbon-carbon bonds. This allows for the creation of more complex molecules and functional groups. These reactions can also be used to introduce alkynes and ketones into a molecule for further modification or functionalization. Additionally, alkyne-ketone reactions are often used in natural product synthesis and pharmaceutical development.

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