Electronic Tuning of Iron–Oxo-Mediated C
H Activation: Effect of Electron-Donating Ligand on Selectivity
Yutaka Hitomi*,
Kengo Arakawa,
Masahito Kodera
Article first published online: 11 SEP 2013DOI: 10.1002/chem.201302111Keywords:
C
H activation;
homogeneous catalysis;
hydroxylation;
iron;
oxidation
Abstract: We have reported previously that an iron(III) complex supported by an anionic pentadentate monoamido ligand, dpaqH (dpaqH=2-[bis(pyridin-2-ylmethyl)]amino-N-quinolin-8-yl-acetamido), promotes selective C
H hydroxylation with H2O2 with high regioselectivity. Herein, we report on the preparation of FeIII–dpaq derivatives that have a series of substituent groups at the 5-position of a quinoline moiety in the parent ligand dpaqH (dpaqR, R: OMe, H, Cl, and NO2), and examine them with respect to their catalytic activity in C
H hydroxylation with H2O2. As the substituent group becomes more electron-withdrawing, both the selectivity and the turnover number increase, but the selectivity of epoxidation shows the opposite trend.
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