Selective α-Methylation of Aryl Ketones Using Quaternary Ammonium Salts as Solid Methylating Agents.

We describe the use of phenyl trimethylammonium iodide (PhMe 3 NI) as an alternative methylating agent for introducing a CH 3 group in α-position to a carbonyl group. Compared to conventional methylating agents, quaternary ammonium salts have the advantages of being nonvolatile, noncancerogenic, and easy-to-handle solids. This regioselective method is characterized by ease of operational setup, use of anisole as green solvent, and yields up to 85%.