cs8b01753_si_001.pdf (6.64 MB)
Dual Effects of Cyclopentadienyl Ligands on Rh(III)-Catalyzed Dehydrogenative Arylation of Electron-Rich Alkenes
journal contribution
posted on 2018-07-19, 00:00 authored by Weidong Lin, Weiwei Li, Dandan Lu, Feng Su, Ting-Bin Wen, Hui-Jun ZhangDespite
extensive research on transition metal-catalyzed Fujiwara–Moritani
type C–H olefinations, the alkenes used in these transformations
are still
mainly limited to active acrylate esters and styrenes. Selective aryl
C–H
olefination with electron-rich alkenes is recognized as a challenging
issue. We herein report that simple and readily accessible electron-deficient
[CpRh(III)] and [CpCF3Rh(III)]
(CpCF3 = C5Me4CF3) complexes are powerful catalysts for dehydrogenative arylation
of electron-rich alkenes, including vinyl acetates, enamides, and
vinyl ethers. Employing an electron-withdrawing Cp or CpCF3 ligand instead of the privileged Cp* (C5Me5) ligand not only can facilitate the electrophilic
aryl C–H rhodation but also can lower the olefin insertion
barrier. Both
electron-withdrawing and electron-donating directing groups such as
-CONR2 and -NHAc could be employed in these reactions,
which
provides convenient routes toward a series styryl acetates, N-acetylindoles, and aryl methyl ketones.