Direct C(sp 2 )−H Hydroxylation of Arenes with Palladium(II)/Oxygen Using Sulfoximines as a Recyclable Directing Group

The aerobic palladium(II) catalysis presented herein offers facile entry to various substituted phenols through site‐selective C−H hydroxylation of arenes by using sulfoximines as a reusable directing group. The notable aspects of our method include the use of molecular oxygen (O 2 ) as the sole oxidant, the activation of molecular oxygen through aldehyde autoxidation, operational simplicity, and the mechanistic studies into the catalytic C−H hydroxylation process.