Reusable Supported Ruthenium Catalysts for the Alkylation of Amines by using Primary Alcohols. Issue 3 (27th January 2014) - Pei Shan, Siah
Abstract Efficient and recyclable ruthenium catalysts were synthesized from readily available polystyrene‐ or silica‐supported phosphine ligands. Catalysts bound to the polymer support through an ether linkage showed good to excellent activity towards the N‐alkylation of primary and secondary amines to afford the alkylated products in 62–99 % yield at 120–140 °C. The supported phosphine ligand/ruthenium ratio was found to be crucial for higher catalytic activity and lower ruthenium leaching. The continuous flow N‐alkylation of amines was demonstrated by using the supported catalyst in a column reactor. By adopting the hydrogen‐borrowing strategy, the synthesis of the anti‐Parkinson agent Piribedil was established in 98 % yield at 140 °C.