Intramolecular C(sp3)-H Bond Oxygenation by Transition-Metal Acylnitrenoids

This study demonstrates for the first time that easily accessible transition-metal acylnitrenoids can be used for controlled direct C(sp(3))-H oxygenations. Specifically, a ruthenium catalyst activates N-benzoyloxycarbamates as nitrene precursors towards regioselective intramolecular C-H oxygenations to provide cyclic carbonates, hydroxylated carbamates, or 1,2-diols. The method can be applied to the chemoselective C-H oxygenation of benzylic, allylic, and propargylic C(sp(3))-H bonds. The reaction can be performed in an enantioselective fashion and switched in a catalyst-controlled fashion between C-H oxygenation and C-H amination. This work provides a new reaction mode for the regiocontrolled and stereocontrolled conversion of C(sp(3))-H into C(sp(3))-O bonds.