Autotandem Catalyst: From Acylhydrazones to ','-Methylaliphatic Acylhydrazides via Transfer Hydrogenation/-Methylation with Methanol Catalyzed by a Cp* Iridium Complex Bearing a Functional Ligand.

A new strategy for the synthesis of ','-methylaliphatic acylhydrazides from acylhydrazones via transfer hydrogenation/-methylation with methanol as both the hydrogen source and the methylating reagent has been proposed and accomplished. In the presence of [Cp*Ir(2,2'-bpyO)(HO)] (1 mol %) and CsCO (0.3 equiv), a range of desired products were obtained in high yields. It was also confirmed that functional units in the bpy ligand of the catalyst are crucial for the catalytic activity of iridium complexes. The mechanistic investigation and practical application of the present catalytic system were also presented.