Chapter 9
Alkynes
![Structure and Physical Properties of Alkynes](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11831.jpg)
In nature, compounds containing both carbon and hydrogen are known as "hydrocarbons". Aliphatic hydrocarbons are compounds whose molecules…
![Nomenclature of Alkynes](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11832.jpg)
Alkynes are unsaturated hydrocarbons characterized by the presence of carbon-carbon triple bonds and have a general formula CnH2n-2. The nomenclature…
![Preparation of Alkynes: Alkylation Reaction](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11834.jpg)
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the…
![Preparation of Alkynes: Dehydrohalogenation](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11835.jpg)
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia.…
![Electrophilic Addition to Alkynes: Hydrohalogenation](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11837.jpg)
Electrophilic addition of hydrogen halides, HX (X = Cl, Br or I) to alkenes forms alkyl halides as per Markovnikov's rule, where the hydrogen…
![Alkynes to Aldehydes and Ketones: Acid-Catalyzed Hydration](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11838.jpg)
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes…
![Alkynes to Carboxylic Acids: Oxidative Cleavage](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11840.jpg)
Alkynes undergo oxidative cleavage in the presence of oxidizing reagents like potassium permanganate and ozone. The triple bond — one σ…
![Reduction of Alkynes to <em>cis</em>-Alkenes: Catalytic Hydrogenation](https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/11841.jpg)
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two…
![Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes](https://cloudfront.jove.com/files/thumbs/58063_t.png)
We present the chemoselective synthesis of 1-(iodoethynyl)-4-methylbenzene, 1-(1,2-diiodovinyl)-4-methylbenzene, and…
![Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts](https://cloudfront.jove.com/files/thumbs/52401_t.png)
Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts
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Ynones are a valuable functional group and building block in organic synthesis. Ynones serve as a precursor to many important organic functional…