Click the structures and reaction arrows in sequence to view the 3D models and animations respectively
The first step of the reaction is the formation of a tosylhydrazone via treatment of the ketone with tosylhydrazine, which is then treated with a strong base (NaOMe), which gives the diazo compound.
Z. Zhang and J. Wang, Tetrahedron, 2008, 64, 6577–6605.