Reductive Amination Reaction of Acetophenone Catalyzed by Ruthenium Complex

Abstract

The catalysts generated in situ from RuCl 2 (PPh 3) 3 and α-amino substituted benzimidazole derivatives L 1 ～L 4 were used to promote the reductive amination of acetophenone to generate α-phenylethylamine, N-(1-phenylethyl) formamide and α-phenylethanol. The bulkier substituent and phenyl group on the ligand will enhance the catalytic activity. The reductive amination of acetophenone was faster at 85 ℃, while the hydrogen transfer of acetophenone to α-phenylethanol became the main reaction at 125 ℃. The hydrogen and amine resouce is the ammonium formate. The plausible mechnism was proposed.

Chemoselective Transfer Hydrogenation of Aldehydes with HCOONH4 Catalyzed by RuCl(CNNPh)(PP) Pincer Complexes

“…[17] HCOONH 4 has also been widely used in the Pd/C-catalyzed conversion of carbonyl compounds into alkanes, [18] nitro derivatives into amines [19] and in the hydrodehalogenation of aromatic chlorides. [20] For the employment of HCOONH 4 in the TH of carbonyl compounds, Grainger [21] recently described the use of Wills' tethered Ru complexesi nt he reduction of ketones,w hereas Nie [22] observed the concomitant TH and reductive amination of acetophenone with RuCl 2 (PPh 3 ) 3 anda mino substituted benzamidazole derivatives. Curiously,t he TH of aldehydes with HCOONH 4 haso nly been described by Iyer in the reduction of 4-methoxybenzaldehyde and trans-cinnamaldehyde catalyzed by Ni[P(OPh) 3 ] 4 at 110 8C, but at av ery low S/C = 30.…”