Ruthenium-Catalyzed N-Alkylation of Amines and Sulfonamides Using Borrowing Hydrogen Methodology

The alkylation of amines by alcohols has been achieved using 0.5 mol % [Ru(p-cymene)Cl₂]₂ with the bidentate phosphines dppf or DPEphos as the catalyst. Primary amines have been converted into secondary amines, and secondary amines into tertiary amines, including the syntheses of Piribedil, Tripelennamine, and Chlorpheniramine. N-Heterocyclization reactions of primary amines are reported, as well as alkylation reactions of primary sulfonamides. Secondary alcohols require more forcing conditions than primary alcohols but are still effective alkylating agents in the presence of this catalyst.