Open Accessmeta C–H Arylation of Electron-Rich Arenes: Reversing the Conventional Site Selectivity
Author(s) -
LuoYan Liu,
Jennifer X. Qiao,
KapSun Yeung,
William R. Ewing,
JinQuan Yu
Publication year - 2019
Publication title -
journal of the american chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.115
H-Index - 612
eISSN - 1520-5126
pISSN - 0002-7863
DOI - 10.1021/jacs.9b07887
Subject(s) - chemistry , selectivity , reversing , pyridine , catalysis , ligand (biochemistry) , alkoxy group , combinatorial chemistry , stereochemistry , medicinal chemistry , organic chemistry , receptor , biochemistry , materials science , alkyl , composite material
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-CO 2 Me), as well as taking advantage of the statistics, are essential for achieving the exclusive meta selectivity.