How does O-benzoyl-N-methylhydroxylamine hydrochloride oxidise this ketone?
The first step is the formation of the Me,O-Bz imine of the ketone. This tautomerises to the enamine which then does a pericyclic rearrangement with the carbonyl of the benzoyl group to install O at the alpha position. Finally  the imine hydrolyses to reveal the ketone. See Aldrich Chemfiles (2007) 7.1, page 7.