Lewis Acid Assisted Nickel-Catalyzed Cross-Coupling of Aryl Methyl Ethers by C−O Bond-Cleaving Alkylation: Prevention of Undesired β-Hydride Elimination

In the presence of trialkylaluminum reagents, diverse aryl methyl ethers can be transformed into valuable products by C−O bond‐cleaving alkylation, for the first time without the limiting β‐hydride elimination. This new nickel‐catalyzed dealkoxylative alkylation method enables powerful orthogonal synthetic strategies for the transformation of a variety of naturally occurring and easily accessible anisole derivatives. The directing and/or activating properties of aromatic methoxy groups are utilized first, before they are replaced by alkyl chains in a subsequent coupling process. The activation of the C−OMe bond in the title reaction is facilitated by Lewis acidic trialkylaluminum compounds, which enhance the oxidative‐addition and transmetalation steps. A nickel catalyst with a bidentate P,P‐ligand prevents the competing β‐hydride elimination so that the alkyl‐substituted products are obtained in high yields.