Abstract
The lithiation of halogenated azobenzenes by a halogen-lithium exchange commonly leads to a substantial degradation of the azo-group to give hydrazine derivatives besides the desired aryl-lithium species. Yields for quenching reactions with electrophiles are therefore low. This work shows that a transmetalation reaction of easily accessible stannylated azobenzenes with methyl lithium leads to a near-quantitative lithiation of azobenzenes in para, meta and ortho position. To investigate the scope of the reaction, various lithiated azobenzenes species were quenched with a variety of electrophiles. Furthermore, mechanistic 119-Sn NMR spectroscopic studies on the formation of lithiated azobenzenes are presented. A tin-ate complex of the azobenzene could be detected at low temperatures.
Original language | English |
---|---|
Number of pages | 9 |
Journal | Chemistry - A European Journal |
Early online date | 26 Jun 2015 |
Publication status | Published - 2015 |
Bibliographical note
Date of Acceptance: 06/05/2015Keywords
- azo compounds
- lithiation
- metalation
- synthetic methods
- tin