Highly Selective and Efficient Ring Hydroxylation of Alkylbenzenes with Hydrogen Peroxide and an Osmium(VI) Nitrido Catalyst

The Os VI nitrido complex, Os VI (N)(quin) 2 (OTs) ( 1 , quin=2‐quinaldinate, OTs=tosylate), is a highly selective and efficient catalyst for the ring hydroxylation of alkylbenzenes with H 2 O 2 at room temperature. Oxidation of various alkylbenzenes occurs with ring/chain oxidation ratios ranging from 96.7/3.3 to 99.9/0.1, and total product yields from 93 % to 98 %. Moreover, turnover numbers up to 6360, 5670, and 3880 can be achieved for the oxidation of p‐xylene, ethylbenzene, and mesitylene, respectively. Density functional theory calculations suggest that the active intermediate is an Os VIII nitrido oxo species.