Related Experiment Video
Updated: Jan 2, 2026
07:49
Characterizing Lewis Pairs Using Titration Coupled with In Situ Infrared Spectroscopy
Published on: February 20, 2020
9.8K
Nitrenium Salts in Lewis Acid Catalysis
Meera Mehta1, Jose M Goicoechea1
1Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Rd., Oxford, OX1 3TA, UK.
Angewandte Chemie (International Ed. in English)
|December 7, 2019
Summary
Nitrenium ions, a rare class of nitrogen-based Lewis acids, are explored as catalysts in organic chemistry. These stable, accessible compounds enable novel Lewis acid catalysis via nitrogen activation.
Area of Science:
- * Organic Chemistry
- * Catalysis
- * Inorganic Chemistry
Background:
- * Nitrogen compounds typically act as Lewis bases (donors) or nucleophiles.
- * Electrophilic nitrogen compounds, or Lewis acids, are uncommon.
- * Nitrenium ions represent a novel class of nitrogen-based Lewis acids with unexplored reactivity.
Purpose of the Study:
- * To investigate the catalytic potential of nitrenium ions in organic transformations.
- * To demonstrate the first examples of Lewis acid catalysis using nitrogen for substrate activation.
- * To assess the stability and accessibility of nitrenium ions as catalysts.
Main Methods:
- * Exploration of nitrenium ions as catalysts in five distinct organic reactions.
- * Utilizing readily available starting materials for nitrenium ion generation.
- * Performing reactions under ambient conditions, including tolerance to moisture.
Main Results:
- * Successful application of nitrenium ions as catalysts in five organic transformations.
- * Demonstration of nitrogen-centered Lewis acid catalysis for substrate activation.
- * Nitrenium ions exhibit stability towards moisture, enabling benchtop reactions.
Conclusions:
- * Nitrenium ions are effective catalysts for a range of organic reactions.
- * This work establishes nitrogen as a viable site for Lewis acid-mediated substrate activation.
- * The accessibility and stability of nitrenium ions facilitate their practical application in catalysis.
Related Concept Videos
01:371° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
4.7K
Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
4.7K
00:55Nitriles to Amines: LiAlH4 Reduction
4.5K
Nitriles are reduced to amines in the presence of strong reducing agents like lithium aluminum hydride through a typical nucleophilic acyl substitution. The reaction requires two equivalents of the reducing agent. The reducing agent acts as a source of hydride ions.
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
4.5K
01:12Preparation of Nitriles
2.5K
One of the common methods to prepare nitriles is the dehydration of amides. This method requires strong dehydrating agents like phosphorous pentoxide or boiling acetic anhydride for converting amides to nitriles. Another reagent namely, thionyl chloride also accomplishes the dehydration of amides, where amide acts as a nucleophile. The first step of the mechanism involves the nucleophilic attack by the amide on the thionyl chloride to form an intermediate. In the next step, the electron pairs...
2.5K
01:20Electrophilic Aromatic Substitution: Nitration of Benzene
8.0K
The nitration of benzene is an example of an electrophilic aromatic substitution reaction. It involves the formation of a very powerful electrophile, the nitronium ion, which is linear in shape. The reaction occurs through the interaction of two strong acids, sulfuric and nitric acid.
8.0K
01:261° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview
3.8K
Nitrous acid and nitric acids are two types of acids containing nitrogen, among which nitrous acid is weaker than nitric acid. Nitrous acid with a pKa value of 3.37 ionizes in water to give a nitrite ion and the hydronium ion.
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by...
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by...
3.8K
01:13Preparation of Amines: Reduction of Amides and Nitriles
2.9K
Nitriles can be reduced to primary amines using reducing agents like lithium aluminum hydride or catalytic hydrogenation. The reduction introduces an amino group with an extra carbon in the skeleton. Nitriles are formed from the reaction between alkyl halides and sodium cyanide through the SN2 mechanism. Primary alkyl halides are the preferred substrates to prepare nitriles.
Amides can be reduced to primary, secondary, and tertiary amines using catalytic hydrogenation, active metals like Fe,...
Amides can be reduced to primary, secondary, and tertiary amines using catalytic hydrogenation, active metals like Fe,...
2.9K