Asymmetric Transfer Hydrogenation Of Acetophenone Research Articles

Biological assays, electrochemical behavior, and theoretical DFT calculations of Ru(II) complexes of chiral phosphinite based based on β-amino alcohols: Transfer hyrogenation of ketones using a HCOOH/Et3N mixture

Synthesis of two phosphinite ligands based on β-amino alcohols, in high yields has been demonstrated. When we treated [Ru(arene)(μ-Cl)Cl]2 {arene:p-cymene,benzene} with chelating phosphinite ligands, we obtained neutral Ru(II)-complexes possessing the general formula [Ru(arene)phosphiniteCl2]. The structure of the ligands and complexes was confirmed using analytical and spectroscopic techniques. The quantum chemical calculations were carried out for the ruthenium complexes at the DFT/CAM-B3LYP level of theory in gas phase. The phosphinite complexes were subjected to cyclic voltammetry studies in order to determine the energies of HOMO and LUMO levels and to estimate their electrochemical and some electronic properties. Organic complex-based memory substrates were immobilized using TiO2-modified ITO electrodes, and the memory functions of phosphinite-based organic complexes were verified by chronoamperometry (CA) and open-circuit potential amperometry (OCPA). In the present study, the antioxidant potentials of ruthenium-based p-cymene and benzene complexes through DPPH radical scavenging, metal chelating, and reducing power activities were also determined. In addition, DNA binding abilities and antimicrobial activities of these complexes against pathogenic bacteria were studied. Finally, the ruthenium complex, (2S)-1-{[(2S)-2-[(diphenylphosphanyl)oxy]propyl][(1R)-1-phenylethyl]amino}propan-2-yldiphenyl phosphinitobis[dichloro(η6-benzene)ruthenium(II)] also catalyzed asymmetric transfer hydrogenation of acetophenone with high conversion (up to 99%) and good enantioselectivity (ee up to 89 %), in the existence of formic acid and triethylamine in dichloromethane medium under air atmosphere.

Enantioselective reduction of prochiral ketones promoted by amino amide ruthenium complexes: A DFT study

The origin of enantioselectivity in the reaction of chiral Ru amino amide complexes in the asymmetric transfer hydrogenation of acetophenone was investigated using DFT calculations. For the most stable active catalysts, the full free energy profiles for the reaction were calculated according to the concerted hydrogen transfer mechanism. We succeeded in reproducing the experimentally observed enantioselectivity for the studied Ru amino amide complexes. Our results indicate that the high enantioselectivity can be explained by a stabilizing CH-π interaction existing between the phenyl group of acetophenone and the aromatic substituent of the catalyst, which plays a significant role in selectivity. Finally, our results show that important insights can be obtained with such a theoretical approach not simply to explain the origin of the reaction asymmetry but also to predict the enantiomeric excess. This can help experimentalists to design new enantioselective catalysts.

New Bifunctional Bis(azairidacycle) with Axial Chirality via Double Cyclometalation of 2,2'-Bis(aminomethyl)-1,1'-binaphthyl.

As a candidate for bifunctional asymmetric catalysts containing a half-sandwich C–N chelating Ir(III) framework (azairidacycle), a dinuclear Ir complex with an axially chiral linkage is newly designed. An expedient synthesis of chiral 2,2′-bis(aminomethyl)-1,1′-binaphthyl (1) from 1,1-bi-2-naphthol (BINOL) was accomplished by a three-step process involving nickel-catalyzed cyanation and subsequent reduction with Raney-Ni and KBH4. The reaction of (S)-1 with an equimolar amount of [IrCl2Cp*]2 (Cp* = η5–C5(CH3)5) in the presence of sodium acetate in acetonitrile at 80 °C gave a diastereomeric mixture of new dinuclear dichloridodiiridium complexes (5) through the double C–H bond cleavage, as confirmed by 1H NMR spectroscopy. A loss of the central chirality on the Ir centers of 5 was demonstrated by treatment with KOC(CH3)3 to generate the corresponding 16e amidoiridium complex 6. The following hydrogen transfer from 2-propanol to 6 provided diastereomers of hydrido(amine)iridium retaining the bis(azairidacycle) architecture. The dinuclear chlorido(amine)iridium 5 can serve as a catalyst precursor for the asymmetric transfer hydrogenation of acetophenone with a substrate to a catalyst ratio of 200 in the presence of KOC(CH3)3 in 2-propanol, leading to (S)-1-phenylethanol with up to an enantiomeric excess (ee) of 67%.

A phosphine-free Mn(I)-NNS catalyst for asymmetric transfer hydrogenation of acetophenone: a theoretical prediction.

The density functional theory (DFT) method was employed to investigate the reaction mechanism of the hydrogen activation and asymmetric transfer hydrogenation (ATH) of acetophenone catalyzed by a well-defined phosphine-free Mn(I)-NNS complex. The calculation results indicate that the Mn-NNS complex has potential high catalytic hydrogenation activity. Meanwhile, the hydrogen transfer step of this reaction is proposed to be a concerted but asynchronous process, and the hydride transfer precedes proton transfer. This work also pointed out that the stereoselectivity of ATH catalyzed by the Mn(I)-NNS complex mainly originates from the noncovalent interaction between the substrate and the catalyst. Additionally, the catalytic activities of Mn-NNS complexes with different X ligands (X = CO, Cl, H, OMe, NCMe, CCMe, and CHCHMe) were compared, and the calculated total reaction energy barriers were all viable, which indicates that these Mn-NNS complexes show higher CO bond hydrogenation activity under mild conditions. This theoretical study predicts that the reactions catalyzed by complexes with H and NCMe ligands exhibit high stereoselectivity with enantiomeric excess (ee) values of 97% and 93%, respectively.

Asymmetric transfer hydrogenation of acetophenone using bis-imine rhodium complexes: Kinetic study and modeling

Asymmetric transfer hydrogenation of acetophenone (APh) to (R)-1-phenylethanol (PhE) was studied in 2-propanol solution in the presence of Rh(1,5-COD)(μ-Cl)]2+L, where COD = cyclooctadiene and L is a bis-aldimine ligand based on (R,R)-1,2-cyclohexanediamine and pyridinecarboxaldehyde. This rhodium (I) complex bearing optically active ligands achieved a maximum turnover frequency (TOF) of 268 h−1 at 78 °C and a moderate maximum enantioselectivity (ee) of 55 % for (R)-1-PhE. A formal kinetic study of the process was carried out using the Rh(1,5-COD)(N,N'-(R,R)-1,2-cyclohexane-1,2-diyl-bis-(1-(pyridine-2-yl)-methanimine)-Cl complex. The induction period for catalyst activation is proposed to involve the rapid reaction of the pre-catalyst with excess iso-propoxide to give the catalytically active Rh(1,5-COD)(N,N'-(R,R)-1,2-cyclohexane-1,2-diyl-bis-(1-(pyridine-2-yl)-methanimine)-OiPr, which leads to the transfer hydrogenation of 1,5-COD. Reaction profiles were obtained by varying the initial concentrations of APh, pre-catalyst, base, acetone, and the temperature. These data were fitted to a kinetic model for the proposed mechanism, and numerical simulation led to a set of rate constants and thermodynamic parameters.

Asymmetric Transfer Hydrogenation of Arylketones Catalyzed by Enantiopure Ruthenium(II)/Pybox Complexes Containing Achiral Phosphonite and Phosphinite Ligands.

A family of complexes of the formula trans-[RuCl2(L)(R-pybox)] (R-pybox = (S,S)-iPr-pybox, (R,R)-Ph-pybox, L = monodentate phosphonite, PPh(OR)2, and phosphinite, L = PPh2(OR), ligands) were screened in the catalytic asymmetric transfer hydrogenation of acetophenone, observing a strong influence of the nature of both the R-pybox substituents and the L ligand in the process. The best results were obtained with complex trans-[RuCl2{PPh2(OEt)}{(R,R)-Ph-pybox}] (2c), which provided high conversion and enantioselectivity (up to 96% enantiomeric excess, e.e.) for the reduction of a variety of aromatic ketones, affording the (S)-benzylalcohols.

Synthesis, Crystal Structure of Chiral Ferrocenyl Amino Alcohols, and Its Use for Asymmetric Transfer Hydrogenation

Two chiral ferrocenyl amino alcohols (IIIa and IIIb) have been synthesized for the iridium catalyzed asymmetric transfer hydrogenation of aromatic ketones. The structures of two chiral ferrocenyl amino alcohols have been determined by single crystal X-ray diffraction (CIF files CCDC nos. 1056737 (IIIa) and 1056734 (IIIb)). The results show that the activity and enantioselectivity of the chiral iridium catalyst are very sensitive to the substrate structure. Ir(I)-catalyzed asymmetric transfer hydrogenation of acetophenone resulted in moderate to good yield and lower enantioselectivity; asymmetric transfer hydrogenation of proopiophenone and 2-benzoylpyridine resulted in lower yield and lower enantioselectivity; as for 4-benzoylpyridine, good results have been achieved.

P‐Stereogenic PN(H)P Iron(II) Catalysts for the Asymmetric Hydrogenation of Ketones: The Importance of Non‐Covalent Interactions in Rational Ligand Design by Computation

AbstractThe P‐stereogenic PN(H)P pincer ligands (R(Me)PCH2CH2)2NH (R=Cy, (S,S)‐1 a; R=tBu, (S,S)‐1 b; R=Ph, (R,R)‐1 c) and their iron(II) derivatives [FeBr2(CO)(PN(H)P)] (2 a–2 c) and [FeHBr(CO)(PN(H)P)] (3 a–3 c) were developed by DFT‐driven ligand design. In a preliminary study, the P(Cy)Me‐based pincer (S,S)‐1 a and its Fe(II) complex 3 a were prepared, tested in the asymmetric transfer hydrogenation of acetophenone, and studied by Density Functional Theory (DFT). Based on the good agreement between the experimental and calculated enantioselectivity, rational design of the pincer by DFT was attempted, which suggested high enantioselectivity for the tert‐butyl and phenyl analogues 3 b and 3 c. Therefore, a new synthetic protocol was developed for (R,R)‐1 c using Buono's (S)‐(1‐(OH)Et)P(Me)Ph⋅BH3 as P‐stereogenic synthon. Against the DFT prediction, 3 c gave 1‐phenylethanol with 44% ee, which was reproduced by increasing the level of theory from DFT to post‐Hartree‐Fock Møller‐Plesset (MP2). This result can be explained by the overestimation of the enantiodeterming CH/π interaction by DFT, which reiterates the need for accurate energies in the assessment of small energy differences such as in asymmetric catalysis.magnified image

Chiral Amino‐Acid‐Amide Based Ionic Liquids as a Stereoselective Organocatalyst in Asymmetric Transfer Hydrogenation of Acetophenone at Room‐Temperature

AbstractChiral Ionic Liquids (CILs) of amino acid amide were synthesized and used as novel organo catalyst for Asymmetric Transfer Hydrogenation (ATH) of acetophenone at room temperature. The developed CILs show very high yield and excellent enantio‐selectivity in transfer hydrogenation of acetophenone.

The Application of New Chiral Ferrocene Ligands in Asymmetric Transfer Hydrogenation of Ketones

Four easily available ferrocenyl chiral ligands have been screened firstly for ruthenium (II)-catalyzed asymmetric transfer hydrogenation of acetophenone with HCOOH/Et3N azeotrope as the hydrogen source. A moderate chemical yield of 1-phenylethanol with 83% ee was obtained when (RC, SFc)-1-(Diphe-nylphosphino)-2-[1-N-(3-methylpyridin-2-ylmethyl) ethyl] ferrocene (L1) was used. Particularly, both ruthenium and iridium could coordinate with L1 to accomplish the asymmetric reduction of series of aromatic ketones separately. The desired products were achieved with up to 86% ee.<

From imine to amine: an unexpected left turn. Cis-β iron(ii) PNNP' precatalysts for the asymmetric transfer hydrogenation of acetophenone.

A novel PNN ligand bearing an orthophenylene group and a primary amine was synthesized with the aid of a palladium-catalyzed amination and reacted with phosphonium dimers [-PR2CH2CH(OH)-]2[Br]2 R = Et, iPr, Cy, Ph, xylyl, and o-Tol, and [Fe(OH2)6]2+ to produce a new series of cis-β iron(ii) PNNP' precatalysts cis-β-[Fe(Br)(CO)(PNNP')]BPh4 as a pair of diastereomers. The more stable orthophenylene amido group was chosen to imitate and replace the enamido moiety of a highly active iron precatalyst for the asymmetric transfer hydrogenation (ATH) of ketones in an attempt to prevent its deactivation caused by reduction of the enamido group. This objective was partially achieved using the complex with a PEt2 group which catalyzed the transfer hydrogenation in isopropanol of 150 000 equivalents of acetophenone to racemic 1-phenylethanol. With a low acetophenone to catalyst ratio of 500 to 1, the catalytic activity was moderate and the enantiomeric excess (ee) of the product 1-phenylethanol ranged surprisingly from 94% (R) to 95% (S) depending on the nature of PR2 and whether the precatalyst contained an imine or amine donor. The amine precatalyst with a PEt2-group produced a more stable hydride species when activated, allowing the reaction mixture to be heated to 75 °C to obtain a TON of 8821 for acetophenone while retaining the high ee of 95% (S). The activation pathway in basic isopropanol (iPrOH) was studied for three precatalysts to elucidate that the cis-β precatalysts rearrange to form trans hydride complexes. The study suggests that the enantioselectivity of these complexes is determined by from which side of the PNNP' plane the hydride transfer occurs.

Synthesis and Application of Magnetic Noyori-Type Ruthenium Catalysts for Asymmetric Transfer Hydrogenation Reactions in Water

A Noyori-type ruthenium catalyst was immobilized on magnetic platforms consisting of carbon-coated cobalt nanoparticles and different polymers. Both reactivity and enantioselectivity of these catalysts were benchmarked in the asymmetric transfer hydrogenation of acetophenone in an aqueous medium. The best catalyst, having connected the ruthenium catalyst to the nanoparticle by a poly(styrene) matrix, was characterized by infrared (IR) spectroscopy and via a superconducting quantum interference device (SQUID) to determine the saturation magnetization of the magnetic material as well as by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). A variety of aryl methyl ketones could be reduced to their corresponding alcohols with good yields (81–100%) and selectivity (91–99% ee), and catalyst recovery and reuse was evaluated over 10 runs with ruthenium leaching into the product of <10 ppm, meeting the pharmaceutical requirements for ruthenium impurities of orally available drugs.

Short‐Mesochannel SBA‐15‐Supported Chiral 9‐Amino Epicinchonine for Asymmetric Transfer Hydrogenation of Aromatic Ketones

AbstractA short‐mesochannel SBA‐15 material functionalized with propylthiol groups was prepared by co‐condensation and applied to the immobilization of chiral 9‐amino epicinchonine. After complexing with [Ir(cod)Cl]2 (cod=1,5‐cyclooctadiene), these mesoporous materials were evaluated as catalysts for the asymmetric transfer hydrogenation of aromatic ketones. Higher enantioselectivities and comparable, or even higher, catalytic activities were achieved compared with the free catalyst. Both the short mesochannel and co‐condensation approach for short‐mesochannel SBA‐15 materials functionalized with propylthiol groups, [SSBA‐SH(x)] materials were demonstrated to contribute to the excellent catalytic performance. In addition, the catalyst SSBA‐AEC(5)/Ir (AEC=9‐amino epicinchonine), with low 3‐mercaptopropyltrimethoxysilane (MPTMS) content, showed the best catalytic performance; a high enantiomeric excess of 84 % (homogeneous ee=60 %) along with a conversion of 97 % was achieved within 1 h for asymmetric transfer hydrogenation of acetophenone. Moreover, these immobilized catalysts showed high stability during the reaction and could be recovered for reuse.

Chiral Amino-acids Derivatives-Ruthenium Catalyzed Asymmetric Transfer Hydrogenation of Ketones

Benzimidazoles derived from chiral amino acids and benzimidazoles derived from dipeptides were prepared and proved to be efficient ligands in the ruthenium catalyzed asymmetric transfer hydrogenation of acetophenone. Employing ligand 2 in the reduction of acetophenone resulted in better activity and enantioselectivity (with 15400 h TOF and 77% ee). Through structure-activity correlations, the corresponding metal-ligand bifunctional mechanism was speculated. In addition, the catalytic system of [RuCl2(p-cymene)]2/2 exhibited reversed temperature effects, which explained through kinetics data. The enantioselectivity was increased from 38% to 43% when LiCl was added in dipeptides derived benzimidazoles 7/[RuCl2(p-cymene)]2 catalyzed asymmetric transfer hydrogenation.

Details of the Mechanism of the Asymmetric Transfer Hydrogenation of Acetophenone Using the Amine(imine)diphosphine Iron Precatalyst: The Base Effect and The Enantiodetermining Step

The excellent ketone asymmetric transfer hydrogenation (ATH) systems using the precatalysts (S,S)-trans-[FeCl(CO)(PPh2CH2CH2NHCHPhCHPhNCHCH2PAr2)]BPh4 (Ar = Ph (1), p-tolyl (2)) have a fascinating dependence of activity on the base concentration, which is investigated here. The reaction of complex 1 or 2 with 1 equiv of the strong base potassium tert-butoxide in THF for 2–7 days produces the neutral amine(ene-amido) complexes [FeCl(CO)(PPh2CH2CH2NHCHPhCHPhNCHCHPAr2)] (8 and 9). These monodeprotonated complexes have been completely characterized by NMR, EA, and FT-IR spectroscopy and mass spectrometry, and the structure of 9 has been further confirmed by single-crystal X-ray diffraction to reveal a structure with the NH and FeCl bonds parallel and the proton and chloride ligands next to each other. The structures of 8 and 9 and their 1H NMR patterns are similar to those of the active catalyst for the ATH of ketones that is postulated to have NH and FeH bonds parallel with the protonic and hydridic hydrogens adjacent. Identical key nuclear Overhauser effect (NOE) correlations in both 8 and the hydrido complex provide further evidence for the postulated structure of the amine iron hydride intermediate. The catalyst system is not active for the transfer hydrogenation of acetophenone, unless greater than 2 equiv of base is added to activate the precatalyst. The addition of base (up to 8 equiv per iron) increases the reaction rate, while a further increase of the base concentration shows a reduction of activity. The loss of activity with less than 2 equiv of base results from a side reaction of the active amido(ene-amido) complexes with 2-propanol to form an inactive neutral bis(amido) iron complex, which was characterized by NMR spectroscopy. Structural evidence for this was provided by the X-ray crystal structure determination of an analogous bis(amino) iron(II) complex, generated from the reaction of the amine(ene-amido) iron complex with methanol in C6D6 in the presence of BF4–. The presence of excess base prevents this side reaction, thereby favoring the reaction which forms the active amine iron hydride species that is in the catalytic cycle. The structure of the transition state for the reaction of the amine hydrido iron catalyst with acetophenone has been successfully modeled using density functional theory (DFT) calculations. The (R) configuration of the product 1-phenylethanol is induced by the position of the phenyl groups on the catalyst and a π–π stabilizing interaction between the aryl ring on the ketone and the ene-amido moiety on the ligand.

Catalytic sugar-assisted transfer hydrogenation with Ru(II), Rh(III) and Ir(III) halfsandwich complexes

The application of halfsandwich ruthenium(II), rhodium(III) and iridium(III) complexes of four different methyl 2,3-diamino-4,6-O-benzylidene-2,3-dideoxy-α-D-hexopyranosides and a methyl 2-amino-3-tosylamido-α-D-glucopyranoside as catalyst precursors in asymmetric transfer hydrogenation of acetophenone is reported. The configuration of the hexopyranosides and the type of arene ligands determine the formation of R- or S-1-phenylethanol up to 66% ee. A large influence of the substitution pattern of the arene ligands on the extent of the enantiomeric excess is demonstrated. The results are interpreted by means of DFT calculations.

ChemInform Abstract: Asymmetric oxa‐Michael‐aza‐Henry Cascade Reaction of 2‐Hydroxyaryl‐Substituted α‐Amido Sulfones and Nitroolefins Mediated by Chiral Squaramides.

A series of chiral squaramides were employed in the oxa-Michael-aza-Henry cascade reaction of 2-hydroxyaryl-substituted α-amido sulfones and nitroolefins. In the presence of 10 mol % of a squaramide catalyst and K2CO3 (aq) in CHCl3 at 0 °C, this reaction proceeded smoothly to afford chiral multisubstituted 4-amino-3-nitrobenzopyrans, bearing a readily removable N-Boc protecting group (Boc=tert-butoxycarbonyl), in excellent yields (up to 98 %) and enantioselectivity [up to 98:2 enantiomeric ratio (er) and 93:7 diastereomeric ratio (dr)]. The 4-amino-3-nitrobenzopyrans were converted into chiral 3,4-diamino chromanes, which were further exploited as chiral ligands in the asymmetric transfer hydrogenation of acetophenone, providing 1-phenylethanol in up to 84 % yield and 93.5:6.5 er.

Iridium(I) complexes bearing the (S,S)-iPr-pybox ligand in the asymmetric transfer hydrogenation of acetophenone

The complex [Ir(η2-EtO2CCCCO2Et)2{κ3-N,N,N-(S,S)-iPr-pybox}][PF6] ((S,S)-iPr-pybox=2,6-bis[4′-(S)-isopropyloxazolin-2′-yl]pyridine) (2) has been synthesized from the complex [Ir(η2-C2H4)2{κ3-N,N,N-(S,S)-iPr-pybox}][PF6] (1) by substitution of both ethylene ligands by two diethyl acetylenedicarboxylate ligands. Iridium(III) complexes have been obtained from the complexes [Ir(η2-C2H4)2{κ3-N,N,N-(S,S)-iPr-pybox}][PF6] (1) and [Ir(η2-RCCR)2{κ3-N,N,N-(S,S)-iPr-pybox}][PF6] (R=CO2Et (2), CO2Me (3)) by oxidative addition reactions. Thus, the addition of PhICl2 and Br2 to the iridium(I) complex 1 provides the iridium(III) complexes [IrCl2(η2-C2H4){κ3-N,N,N-(S,S)-iPr-pybox}][PF6] (4) and [IrBr(η1-CH2CH2Br)(η2-C2H4){κ3-N,N,N-(S,S)-iPr-pybox}][PF6] (5), respectively. The structure of the complex 5 has been determined by single-crystal X-ray diffraction analysis. The treatment of complexes 3 and 2 with I2 and allyl chloride results in the stereoselective formation of the iridium(III) complexes [IrI2(η2-MeO2CCCCO2Me){κ3-N,N,N-(S,S)-iPr-pybox}][PF6] (6) and [IrCl(η1-CH2CHCH2)(η2-EtO2CCCCO2Et){κ3-N,N,N-(S,S)-iPr-pybox}][PF6] (7), respectively. The catalytic activity of the iridium(I) complexes 2 and 3 in transfer hydrogenation of acetophenone has been examined.

Asymmetric oxa‐Michael‐aza‐Henry Cascade Reaction of 2‐Hydroxyaryl‐Substituted α‐Amido Sulfones and Nitroolefins Mediated by Chiral Squaramides

AbstractA series of chiral squaramides were employed in the oxa‐Michael‐aza‐Henry cascade reaction of 2‐hydroxyaryl‐substituted α‐amido sulfones and nitroolefins. In the presence of 10 mol % of a squaramide catalyst and K2CO3 (aq) in CHCl3 at 0 °C, this reaction proceeded smoothly to afford chiral multisubstituted 4‐amino‐3‐nitrobenzopyrans, bearing a readily removable N‐Boc protecting group (Boc=tert‐butoxycarbonyl), in excellent yields (up to 98 %) and enantioselectivity [up to 98:2 enantiomeric ratio (er) and 93:7 diastereomeric ratio (dr)]. The 4‐amino‐3‐nitrobenzopyrans were converted into chiral 3,4‐diamino chromanes, which were further exploited as chiral ligands in the asymmetric transfer hydrogenation of acetophenone, providing 1‐phenylethanol in up to 84 % yield and 93.5:6.5 er.

Asymmetric Transfer Hydrogenation of Acetophenone Promoted by Chitosan Ester Ruthenium Complex

The catalytic properties of the catalyst generated in situ from the reaction of Ru(II) compounds with chitosan based ligands were evaluated in the asymmetric transfer hydrogenation of acetophenone using isopropanol or sodium formate as hydrogen source. The effects of reaction time, temperature and the dosage of THF on the performance of the catalyst were evaluated. The O-stearoyl chitosan (SCS) is in the form of micelles with the average size of 213 nm in i-PrOH/THF solution. Using i-PrOH as hydrogen source, the ee value of 1-phenylethanol is up to 62.9%. The dosage of THF strongly affected the catalytic activity. The catalytic activity (TOF) is up to 30.4 h -1 at the volume ratio of i-PrOH to THF being 1∶1. The TOF increased with the increase of the temperature. At 100 ℃, the TOF is up to 48.5 h -1 . While using HCOONa as the hydrogen source, the TOF and ee values of 1-phenylethanol are 29.4 h -1 and 53.0%, respectively.