A New and Eco-Friendly Method for Reduction of Ketones in Water

This paper reports a new, practical, and environmentally friendly catalytic system for reduction of the ketones to the related alcohols with efficient reaction performance in water. Catalysts were generated in situ from rhodium, ruthenium and iridium transition metal compounds with commercially available piperidines [Piperidine (L-1), 2-hydroxymethylpiperidine (L-2), 3-hydroxymethylpiperidine (L-3), 4-hydroxymethylpiperidine (L-4), 4-hydroxypiperidine (L-5)] as bifunctional ligands. Catalyst generated from RuCl2(PPh3)(3) and 4-hydroxymethyl piperidine have shown the best activity in aqueous media which gave a 100% product yield. RuCl2(PPh3)(3), has showed a better efficiency than [RuCl2(p-cymene)](2), IrCl(PPh3)(3), or RhCl(PPh3)(3) in HCOOH-HCOONa buffer solution. This study was also investigated the relationship between the structure of hydroxymethyl piperidine ligands and the catalytic activity.