Abstract
The N-arylation of tertiary amines to provide sp 3 quaternary ammonium salts is a challenge in organic chemistry. To date, no general method for such arylations has been established. Here, we summarize a variety of strategies that have been tested, starting with harsh nucleophilic aromatic substitutions, through to the use of copper catalysis and the application of strong electrophiles, such as phenyl cations and benzynes. The achievements and limitations of each method are summarized, and the challenges yet to be met in the synthesis of charged ammonium compounds are described. 1 Introduction 2 Alkylation of Anilines: The Menshutkin Reaction 3 Arylations 3.1 Nucleophilic Aromatic Substitutions by Tertiary Amines 3.2 Preparation of N -Arylpyridinum Salts from Zincke and Pyrylium Salts 3.3 Arylations Using Phenyl Cations 3.4 Copper-Catalyzed Arylation of N-Heteroarenes 3.5 Benzynes as Aryl Electrophiles 4 Conclusions and Perspective.
Original language | American English |
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Pages (from-to) | 3535-3545 |
Number of pages | 11 |
Journal | Synthesis (Germany) |
Volume | 49 |
Issue number | 16 |
DOIs | |
State | Published - 16 Aug 2017 |
Keywords
- Menshutkin reaction
- Zincke reaction
- arylation
- benzyne chemistry
- copper catalysis
- nucleophilic aromatic substitution
- phenyl cations
- quaternary ammonium salts
All Science Journal Classification (ASJC) codes
- Catalysis
- Organic Chemistry