Electronic Tuning of Iron–Oxo‐Mediated CH Activation: Effect of Electron‐Donating Ligand on Selectivity

We have reported previously that an iron(III) complex supported by an anionic pentadentate monoamido ligand, dpaq H (dpaq H =2‐[bis(pyridin‐2‐ylmethyl)]amino‐ N ‐quinolin‐8‐yl‐acetamido), promotes selective CH hydroxylation with H 2 O 2 with high regioselectivity. Herein, we report on the preparation of Fe III –dpaq derivatives that have a series of substituent groups at the 5‐position of a quinoline moiety in the parent ligand dpaq H (dpaq R , R: OMe, H, Cl, and NO 2 ), and examine them with respect to their catalytic activity in CH hydroxylation with H 2 O 2 . 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.