Related Experiment Video
Updated: Jul 9, 2025

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Rapid and General Access to α-Haloketones Using Quaternary Ammonium Salts as Halogen Sources
Nan Wu1, Mengfei Jiang1, Ashley Cao1
1Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou 221004, China.
A new, scalable method efficiently prepares alpha-halogenated ketones using N-alkenoxypyridinium salts. This approach offers mild conditions and broad functional group compatibility for organic synthesis.
Area of Science:
- Organic Chemistry
- Synthetic Chemistry
Background:
- Alpha-halogenated ketones are valuable synthetic intermediates.
- Existing methods for their preparation can be limited by harsh conditions or narrow substrate scope.
Purpose of the Study:
- To develop a general, rapid, and scalable method for synthesizing alpha-halogenated ketones.
Main Methods:
- Utilized N-alkenoxypyridinium salts as substrates.
- Employed quaternary ammonium salts as halogen sources.
- Conducted reactions under mild conditions.
Main Results:
- Achieved efficient preparation of alpha-halogenated ketones.
- Demonstrated excellent functional group tolerance.
- Showcased short reaction times and a wide substrate scope.
Conclusions:
- The developed method provides a versatile and efficient route to alpha-halogenated ketones.
- This protocol is suitable for various synthetic applications in organic chemistry.
Related Concept Videos
Base-Promoted α-Halogenation of Aldehydes and Ketones
Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
α-Halogenation of Carboxylic Acid Derivatives: Overview
Multiple Halogenation of Methyl Ketones: Haloform Reaction
Reactions of α-Halocarbonyl Compounds: Nucleophilic Substitution
Preparation of Amines: Alkylation of Ammonia and Amines
Each alkylation step makes the nitrogen center more nucleophilic, which triggers successive alkylations until a quaternary ammonium salt is formed. Considering...

