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作为乙烯转移催化剂的2-替代DMAP-N-氧化物的合理设计:阿兹拉克的动态动态分辨率

  • 0Henan Key Laboratory of Organic Functional Molecules and Drug Innovation, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China.
Journal of the American Chemical Society +

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2020年十月29日

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Diazonium Group Substitution: –OH and –H 01:19

3.2K

Nitrous acid, a weak acid, is prepared in situ via the reaction of sodium nitrite with a strong acid under cold conditions. This nitrous acid prepared in situ reacts with primary arylamines to form arenediazonium salts. Such reactions are known as diazotization reactions. As shown in Figure 1, the formation of arenediazonium salts begins with the decomposition of nitrous acid in an acidic solution to give nitrosonium ions.

Figure 1.
A primary arylamine attacks the nitrosonium ion to form an...

Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic S<sub data-lazy-src=

2.5K

Treating arylamines with nitrous acid gives aryldiazonium salts that are effective substrates in nucleophilic aromatic substitution reactions. The diazonio group in these salts can be easily displaced by different nucleophiles, yielding a wide variety of substituted benzenes. The leaving group departs as nitrogen gas, and this easy elimination is the driving force for the substitution reaction.
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo,...

Carboxylic Acids to Methylesters: Alkylation using Diazomethane 01:33

2.7K

Carboxylic acids react with diazomethane in an ether solvent via alkylation at the carboxylate oxygen atom to give methyl esters of the corresponding acid with excellent yields.

Diazomethane is a yellow gas having a boiling point of −23 °C. It is conveniently prepared by the action of a base on N-methyl-N-nitrosourea or N-methyl-N-nitrosotoluenesulphonamide.
The esterification mechanism involves the protonation of diazomethane by the carboxylic acid to yield a carboxylate salt and...

Amines to Amides: Acylation of Amines 01:19

3.2K

Various carboxylic acid derivatives (such as acid chlorides, esters, and anhydrides) can be used for the acylation of amines to yield amides. The reaction requires two equivalents of amines. The first amine molecule functions as a nucleophile and attacks the carbonyl carbon to produce a tetrahedral intermediate. This is followed by the loss of the leaving group and restoration of the C=O bond.
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary...

Aryldiazonium Salts to Azo Dyes: Diazo Coupling 01:11

3.4K

The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para...

1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO<sub data-lazy-src=

4.5K

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.

Figure 1. The mechanism of the diazotization reaction of primary amines.
As illustrated in Figure 1, in the...