このページは機械翻訳されています。他のページは英語で表示される場合があります。 View in English

[1.1.1]プロペランによるケトンの環拡張

  • 0Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India.

まとめ

この要約は機械生成です。

関連する概念動画

Conformations of Cycloalkanes 02:29

14.0K

Adolf von Baeyer attempted to explain the instabilities of small and large cycloalkane rings using the concept of angle strain — the strain caused by the deviation of bond angles from the ideal 109.5° tetrahedral value for sp3  hybridized carbons. However, while cyclopropane and cyclobutane are strained, as expected from their highly compressed bond angles, cyclopentane is more strained than predicted, and cyclohexane is virtually strain-free. Hence, Baeyer’s theory that...

Ketones with Nonenolizable Aromatic Aldehydes: Claisen–Schmidt Condensation 01:01

4.3K

Benzaldehyde, like formaldehyde, lacks an α hydrogen and cannot enolize to form an enolate. Hence, the reaction of benzaldehyde with a ketone in the presence of an aqueous base forms a single crossed product. This reaction is referred to as Claisen–Schmidt condensation.
As the self-condensation of ketones is generally not favored in basic conditions, the self-condensed products do not form in the reaction between ketones and benzaldehyde. The general reaction of Claisen–Schmidt...

Alkynes to Aldehydes and Ketones: Acid-Catalyzed Hydration 02:40

10.5K

Introduction
Analogous to alkenes, alkynes also undergo acid-catalyzed hydration. While the addition of water to an alkene gives an alcohol, hydration of alkynes produces different products such as aldehydes and ketones.       

Since the rate of acid-catalyzed hydration of alkynes is much slower than alkenes, a mercuric salt like mercuric sulfate (HgSO4) is usually added to facilitate the reaction. Hydration of terminal alkynes follows Markovnikov's rule; however, for internal alkynes,...

Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation 02:47

20.6K

Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.

Mechanism
The hydroboration-oxidation reaction is a two-step...

Conformations of Ethane and Propane 02:18

16.7K

In an organic molecule, free rotation about the carbon-carbon single bond results in energetically different conformers of the molecule. Due to this rotation, called the internal rotation, ethane has two major conformations — staggered and eclipsed.
Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front carbon placed at 60°dihedral angles relative to the C-H bonds on the back carbon, leading to a reduced torsional strain. In staggered...

α-Alkylation of Ketones via Enolate Ions 01:10

3.7K

Ketones with α protons are deprotonated by strong bases like lithium diisopropylamide (LDA) to form enolate ions. The anion is stabilized by resonance, and its hybrid structure exhibits negative charges on the carbonyl oxygen and the α carbon. This ambident nucleophile can attack an electrophile via two possible sites: the carbonyl oxygen, known as O-attack, or the α carbon, known as C-attack. The nucleophilic attack via the carbanionic site is preferred. This is due to the...