Details

Autor(en) / Beteiligte

• Demmans, K. Z.
• Ko, O. W. K.
• Morris, R. H.

Titel

Aqueous biphasic iron-catalyzed asymmetric transfer hydrogenation of aromatic ketones

Ist Teil von

• RSC advances, 2016-01, Vol.6 (91), p.88580-88587

Erscheinungsjahr

2016

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• For the first time, an iron( ii ) catalyst is used in the biphasic asymmetric transfer hydrogenation (ATH) of ketones to enantioenriched alcohols employing water and potassium formate as the proton and hydride source, respectively. The precatalyst [FeCl(CO)(P–NH–N–P)]BF 4 (P–NH–N–P = ( S , S )-PPh 2 CH 2 CH 2 NHCHPhCHPhNCHCH 2 PPh 2 ) in the organic phase with the substrate is activated by base to produce a system that rivals the best ruthenium biphasic ATH catalysts in activity but not enantioselectivity. Biorenewable 2-methyltetrahydrofuran as a cosolvent and biodegradable TWEEN80 as a surfactant were added to the reaction mixture to greatly decrease the mass-transfer limitations caused by the biphasic reaction mixture. The enantioselectivity of the reduction was as high as 76% depending on the substitution pattern of the arylketone employed. NMR studies verified the formation of an iron hydride [FeH(CO)(PPh 2 CH 2 CH 2 NHCHPhCHPhNCHCHPPh 2 )] intermediate as was observed in our 2-propanol-based ATH studies.