Rhenium(I)-Catalyzed C‑Methylation of Ketones, Indoles, and Arylacetonitriles Using Methanol

A ReCl­(CO)₅/MeC­(CH₂PPh₂)₃ (L2) system was developed for the C-methylation reactions utilizing methanol and base, following the borrowing hydrogen strategy. Diverse ketones, indoles, and arylacetonitriles underwent mono- and dimethylation selectively up to 99% yield. Remarkably, tandem multiple methylations were also achieved by employing this catalytic system.