meta C-H Arylation of Electron-Rich Arenes: Reversing the Conventional Site Selectivity.
J Am Chem Soc
; 141(37): 14870-14877, 2019 09 18.
Article
em En
| MEDLINE
| ID: mdl-31449745
ABSTRACT
Controlling site selectivity of C-H activation without using a directing group remains a significant challenge. While Pd(II) catalysts modulated by a mutually repulsive pyridine-type ligand have been shown to favor the relatively electron-rich carbon centers of arenes, reversing the selectivity to favor palladation at the relatively electron-deficient positions has not been possible. Herein we report the first catalytic system that effectively performs meta C-H arylation of a variety of alkoxy aromatics including 2,3-dihydrobenzofuran and chromane with exclusive meta site selectivity, thus reversing the conventional site selectivity governed by native electronic effects. The identification of an effective ligand and modified norbornene (NBE-CO2Me), as well as taking advantage of the statistics, are essential for achieving the exclusive meta selectivity.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Cromanos
/
Hidrocarbonetos
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article