Back to Search
Start Over
Triptycenyl Sulfide: A Practical and Active Catalyst for Electrophilic Aromatic Halogenation Using N-Halosuccinimides
- Source :
- Journal of the American Chemical Society; January 2020, Vol. 142 Issue: 3 p1621-1629, 9p
- Publication Year :
- 2020
-
Abstract
- A Lewis base catalyst Trip-SMe (Trip = triptycenyl) for electrophilic aromatic halogenation using N-halosuccinimides (NXS) is introduced. In the presence of an appropriate activator (as a noncoordinating-anion source), a series of unactivated aromatic compounds were halogenated at ambient temperature using NXS. This catalytic system was applicable to transformations that are currently unachievable except for the use of Br2or Cl2: e.g., multihalogenation of naphthalene, regioselective bromination of BINOL, etc. Controlled experiments revealed that the triptycenyl substituent exerts a crucial role for the catalytic activity, and kinetic experiments implied the occurrence of a sulfonium salt [Trip-S(Me)Br][SbF6] as an active species. Compared to simple dialkyl sulfides, Trip-SMe exhibited a significant charge-separated ion pair character within the halonium complex whose structural information was obtained by the single-crystal X-ray analysis. A preliminary computational study disclosed that the π system of the triptycenyl functionality is a key motif to consolidate the enhancement of electrophilicity.
Details
- Language :
- English
- ISSN :
- 00027863 and 15205126
- Volume :
- 142
- Issue :
- 3
- Database :
- Supplemental Index
- Journal :
- Journal of the American Chemical Society
- Publication Type :
- Periodical
- Accession number :
- ejs51840420
- Full Text :
- https://doi.org/10.1021/jacs.9b12672