Catalysts for the asymmetric transfer hydrogenation of various ketones from [3-[(2S)-2-[(diphenylphosphanyl)oxy]-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride] and [Ru(η6-arene)(μ-Cl)Cl]2, Ir(η5-C5Me5)(μ-Cl)Cl]2 or [Rh(μ-Cl)(cod)]2

Article abstract of DOI:10.1016/j.ica.2019.04.016

The combination of [3-[(2S)-2-[(diphenylphosphanyl)oxy]-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride] with [Ru(η⁶-arene)(μ-Cl)Cl]_2, Ir(η⁵-C₅Me₅)(μ-Cl)Cl]₂ or [Rh(μ-Cl)(cod)]₂, in the presence of KOH/isoPrOH, has been found to generate catalysts that are capable of enantioselectively reducing alkyl, aryl ketones to the corresponding (R)-alcohols. Under optimized conditions, when the catalysts were applied to the asymmetric transfer hydrogenation, we obtained the secondary alcohol products in high conversions and enantioselectivities using only 0.5 mol% catalyst loading. In addition, [3-[(2S)-2-{[(chloro(?⁴-1,5-cyclooctadiene)rhodium)diphenyl phosphanyl] oxy}-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride], (6) complex is much more active than the other analogous complexes in the transfer hydrogenation. Catalyst 6 acts as excellent catalysts, giving the corresponding (R)-1-phenyl ethanol in 99% conversion in 30 min (TOF ≤ 396 h^?1) and in high enantioselectivity (92% ee).

Full text of DOI:10.1016/j.ica.2019.04.016

Inorganica Chimica Acta 492 (2019) 108–118
Contents lists available at ScienceDirect
Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Research paper
Catalysts for the asymmetric transfer hydrogenation of various ketones from
3-[(2S)-2-[(diphenylphosphanyl)oxy]-3-phenoxypropyl]-1-methyl-1H-
[
6
5
imidazol-3-ium chloride] and [Ru(η -arene)(μ-Cl)Cl] Ir(η -C Me )(μ-
2
,
5
5
Cl)Cl] or [Rh(μ-Cl)(cod)]
2
2
Nermin Meriç , Nevin Arslan , Cezmi Kayan , Khadichakhan Rafikovac,d,⁎, Alexey Zazybinc,d
a
b
a
,
d
a,⁎
Aygul Kerimkulova , Murat Aydemir
a
b
c
Department of Chemistry, Faculty of Science, University of Dicle, 21280 Diyarbakir, Turkey
Şırnak University, Department of Field Crops, Faculty of Agriculture, Şırnak 73000, Turkey
Kazakh-British Technical University, School of Chemical Engineering, Almaty, Kazakhstan
Satbayev University, Institute of Chemical and Biological Technologies, Almaty, Kazakhstan
d
A R T I C L E I N F O
A B S T R A C T
The combination of [3-[(2S)-2-[(diphenylphosphanyl)oxy]-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium
Keywords:
6
5
Catalysis
chloride] with [Ru(η -arene)(μ-Cl)Cl] Ir(η -C Me )(μ-Cl)Cl] or [Rh(μ-Cl)(cod)] , in the presence of KOH/
2
,
5
5
2
2
Asymmetric transfer hydrogenation
Phosphinite-CFILs
Ruthenium
isoPrOH, has been found to generate catalysts that are capable of enantioselectively reducing alkyl, aryl ketones
to the corresponding (R)-alcohols. Under optimized conditions, when the catalysts were applied to the asym-
metric transfer hydrogenation, we obtained the secondary alcohol products in high conversions and enantios-
Rhodium
4
electivities using only 0.5 mol% catalyst loading. In addition, [3-[(2S)-2-{[(chloro(ɳ -1,5-cyclooctadiene)rho-
Iridium
dium)diphenyl phosphanyl] oxy}-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride], (6) complex is
much more active than the other analogous complexes in the transfer hydrogenation. Catalyst 6 acts as excellent
−
1
catalysts, giving the corresponding (R)-1-phenyl ethanol in 99% conversion in 30 min (TOF ≤ 396 h ) and in
high enantioselectivity (92% ee).
1
. Introduction
The chemistry of P-based ligands has been extensively investigated
catalysts [10,11]. Phosphinites provide different chemical, electronic
and structural properties compared to phosphines. The metal-phos-
phorus bond is often stronger for phosphinites compared to the related
phosphine due to the presence of electron-withdrawing P-OR group. In
in recent years [1]. These compounds are extremely attractive as po-
tential ligands since various structural modifications are accessible via
simple PeN, PeC and PeO bond formation [2]. Many modified P-based
ligands have significant applications in organometallic chemistry and
catalysis, giving selective catalysts for hydroformylation, hydrosilyla-
tion and, especially transfer hydrogenation [3,4,5,6]. Although many
chiral phosphorus ligands have been synthesized and used in transition-
metal-catalyzed asymmetric reactions, a large number of reactions still
lack effective chiral ligands, and the enantioselectivities in many re-
actions are substrate dependent [7]. While much effort has been de-
voted to the synthesis of aminophosphines and their metal complexes,
similar studies on the analogous phosphinites are less extensive [8,9],
even though some of their complexes have proved to be efficient
addition, the empty σ*-orbital of the phosphinite P(OR)R is stabilized,
2
making the phosphinite a better acceptor [12]. Therefore, the devel-
opment of effective chiral ligands, especially ligands having novel
chiral backbones, is still an important and challenging task for chemists
[13].
Many biologically active compounds, such as pharmaceuticals,
agrochemicals, flavoring, and functional materials, exhibit “handed-
ness” [14]. The preparation of these “handed” (chiral) compounds in
enantiomerically pure form is a challenging goal in modern organic
synthesis. Undoubtedly, the use of chiral metal complex catalysis is a
powerful, economically feasible tool for the preparation of optically
active organic compounds on both laboratory and industrial scales
⁎
Corresponding authors at: Kazakh-British Technical University, School of Chemical Engineering, Almaty, Kazakhstan (K. Rafikova). Department of Chemistry,
Dicle University, TR-21280 Diyarbakır, Turkey (M. Aydemir).
E-mail addresses: hadichahan@mail.ru (K. Rafikova), aydemir@dicle.edu.tr (M. Aydemir).
https://doi.org/10.1016/j.ica.2019.04.016
Received 24 December 2018; Received in revised form 16 March 2019; Accepted 10 April 2019
Available online 11 April 2019
0020-1693/ © 2019 Elsevier B.V. All rights reserved.

N. Meriç, et al.
Inorganica Chimica Acta 492 (2019) 108–118
[
15]. Furthermore, transition metal complexes are influential catalysts
develop useful and magnificent catalysts, in this paper, we report for
the first time the synthesis and full characterization of four new half-
sandwiches ruthenium, iridium and rhodium-arene complexes based on
chiral functionalized ionic liquid, CFIL, and their subsequent applica-
tion in asymmetric transfer hydrogenation of the various ketones.
for organic transformations and when the suitable ligands are asso-
ciated with the metal center, they can offer chemio, regio or stereo
selectivity under mild conditions [16]. However, the appropriate choice
of metal precursors and the reaction conditions are crucial for catalytic
properties [17]. A number of transition metal complexes are known to
be catalyzing hydrogen transfer from an alcohol to a ketone [18,19].
Ketones are the most widespread corporate precursors used in organic
synthesis and reduced ketones, alcohols are very important blocks for
the pharmaceutical and fine chemical industries [20]. Although many
applications require racemic alcohols, the need for enantiomerically
pure products is growing because of their significance as intermediates
for the manufacture of pharmaceuticals and advanced materials
2. Experimental
2.1. Materials and methods
Unless otherwise mentioned, all reactions were carried out under an
atmosphere of argon using conventional Schlenk glassware, solvents
were dried using established procedures and distilled under argon just
prior to use. Analytical grade and deuterated solvents were purchased
from Merck. The starting materials 1-methylimidazole, (S)-2-oxirany-
[
21,22], raising great interest in finding new methods for their pro-
duction. In addition, ketones are one of the most common families of
unsaturated substrates, therefore the enantioselective reduction of
prochiral ketones leading to optically pure secondary alcohols is a
subject of considerable interest from both the academic and the in-
dustrial perpectives [23]. Extensive efforts have been devoted to their
reduction into secondary alcohols especially via hydrogenation [24].
Catalytic transfer hydrogenation (TH) with the aid of a stable hydrogen
donor is a useful alternative process for catalytic hydrogenation by
molecular hydrogen for the reduction of ketones [25,26]. In transfer
hydrogenation, organic molecules such as primary and secondary al-
cohols [27] or formic acid and its salts [28] have been employed as the
hydrogen source. Over the last three decades, most effort on asym-
metric transfer hydrogenation has been focused on the use of ruthe-
nium, rhodium and iridium catalysts [29,30,31].
lanisole, PPh
2
Cl and Et
3
N were purchased from Fluka and used as re-
6
6
ceived. [Ru(η -p-cymene)(µ-Cl)Cl]
2
[54], [Ru(η -benzene)(µ-Cl)Cl]
2
5
[55], Ir(η -C
5
5
Me )(μ-Cl)Cl]
2
[56] and [Rh(μ-Cl)(cod)]
2
[57] were pre-
1
13
pared according to the literature procedures. H (at 400.1 MHz), C (at
3
1
1
100.6 MHz) and P-{ H} NMR (at 162.0 MHz) spectra were recorded
on a Bruker AV 400 spectrometer, with TMS (tetramethylsilane) as an
1
13
internal reference for H NMR and C NMR or 85% H
3
PO as an ex-
4
3
1
1
ternal reference for P-{ H} NMR. The infrared spectra was measured
by an Agilent Cary 630 FTIR, respectively. The FTIR spectra were re-
corded
using
a
universal
ATR
sampling
accessory
−1
(4000–400 cm ). Elemental analysis was carried out on a Costech ECS
4010 instrument. Melting points were recorded by a Gallenkamp Model
apparatus with open capillaries.
It is well-known that ionic liquids are potential replacements for
organic solvents both on laboratory and industrial scales due to their
green characteristics such as thermal stability [32,33,34], lack of vapor
pressure, non-flammability, wide liquid range, wide range of solubility
and miscibility [35,36,37,38]. Furthermore, they can be readily re-
cycled; have profound effect on the activity and selectivity in reactions
and in some cases, facilitate the isolation of products. Therefore, ionic
liquids are considered to be viable substitute for volatile organic sol-
vents [39]. An unusual feature of ionic liquids is the tunability of their
chemical and physical properties by selection of appropriate anion–-
cation combinations [40]. Metal-containing ionic liquids are regarded
as promising new materials that combine the properties of ionic liquids
with additional intrinsic magnetic, spectroscopic, or catalytic proper-
ties, depending on the incorporated metal ion [41]. Furthermore, it has
been known that ionic liquids (ILs) can be functionalized flexibly by
incorporating functional moieties into the IL structure to develop dif-
ferent functionalized ionic liquids (FILs), which dually possess the
characters of the incorporated functionalities as well as those of the ILs
2.2. General procedure for the asymmetric transfer hydrogenation of
ketones
Typical procedure for the catalytic hydrogen-transfer reaction: a
solution of the complexes 3–6 (0.00125 mmol), KOH (0.00625 mmol)
and the corresponding ketone (0.25 mmol) in degassed isoPrOH (5 mL)
was refluxed until the reaction completed. Then, a sample of the re-
action mixture is taken off, diluted with acetone and analyzed im-
mediately by GC, conversions obtained are related to the residual un-
reacted ketone.
2.3. GC analyses
GC analyses were performed on a Shimadzu GC 2010 Plus Gas
Chromatograph equipped with a cyclodex-B (Agilent) capillary column
(30 m × 0.32 mm I.D. × 0.25 μm film thickness). Racemic samples of
alcohols were obtained by reduction of the corresponding ketones with
[
42,43]. The P-based ligands-FILs have long been investigated for the
NaBH and used as the authentic samples for ee % determination. The
4
design of the ionic organometallic compounds and applications to
catalysis [44,45,46]. It has been found that, while the coordinating P
GC parameters for asymmetric transfer hydrogenation of ketones were
as follows; initial temperature, 50 °C; initial time 1.1 min; solvent delay,
4.48 min; temperature ramp 1.3 °C/min; final temperature, 150 °C; in-
itial time 2.2 min; temperature ramp 2.15 °C/min; final temperature,
250 °C; initial time 3.3 min; final time, 44.33 min; injector port tem-
perature, 200 °C; detector temperature, 200 °C, injection volume,
2.0 μL.
(
III) atom is vicinal to the positive charged imidazolium ring, the cor-
responding P-based ligands-FILs are featured with π-acceptor character
as well as σ-donor [47,48]. Hence, the varied coordination behaviors of
such P-based ligands-FILs are in great concerns in the coordinating
chemistry and catalysis, leading to the significant changes of the com-
plex configurations and catalytic performance [49]. In recent years, we
have been synthesized many P-based ligands and used them in transi-
tion-metal-catalyzed asymmetric transfer hydrogenation reaction [50].
However, P-based ligands containing ionic liquid part are rarely used in
this reaction. Furthermore, there is still a need for highly effective
chiral ligands. Therefore, to develop effective highly active well-de-
signed chiral ligands, the features of ionic liquids are combined with
phosphinites. Although some phosphinite ligands and their derivatives
have been employed successfully as ligands in the transfer hydro-
genation of ketones [51,52,53] references therein), a screening of cat-
alytic activities of ionic liquid based phosphinites in this reaction is not
common in the literature. For this reason, we are extending our study to
2.4. Synthesis and characterization of compounds
2.4.1. Synthesis of 3-[(2S)-2-hydroxy-3-phenoxypropyl]-1-methyl-1H-
imidazol-3-ium chloride, (1)
To a stirred solution of 1-methylimidazole (1.03 g, 12.5 mmol) in
ethanol (2 mL) at room temperature was carefully added concentrated
hydrochloric acid (1.05 mL, 12.8 mmol). Caution: neutralization of a
base with a strong acid is highly exothermic. After addition of acid, the
reaction mixture was cooled to room temperature and (S)-2-oxirany-
lanisole (1.95 g, 13 mmol) was added dropwise with stirring, while
maintaining the temperature at 25 °C. The reaction vessel was then
109

N. Meriç, et al.
Inorganica Chimica Acta 492 (2019) 108–118
1
3
sealed and stirred at room temperature for approximately 30 h. The
solvent was removed under reduced pressure on heating at 70 °C, fol-
lowed by heating under high vacuum, to yield a liquid that became
more viscous upon extensive drying, and this was recrystallized from
ethylacetate at 0 °C. The precipitated product was filtered and dried in
vacuo yielding 1 as an off-white solid. Yield: 2.79 g, 83.0%; M.p.:
cymene), 0.72 (d, J = 6.8 Hz, 3H, CH
(100.6 MHz, CDCl -d1, ppm): δ 17.22 (CH
22.56 ((CH CHPh of p-cymene), 30.05 (–CH– of p-cymene), 36.60
(CH N), 50.50 (NCH
3
)
2
CHPh of p-cymene); C NMR
3
3
Ph of p-cymene), 20.25,
3 2
)
3
2
), 66.55 (–CH OPh), 73.73 (d, J = 9.1 Hz,
2
-CHOP), 85.29 (s, aromatic carbons of p-cymene), 88.26 (s, aromatic
carbons of p-cymene), 89.91 (d, J = 8.0 Hz, aromatic carbons of p-
cymene), 94.23 (s, aromatic carbons of p-cymene), 96.41, 110.35
(quaternary carbons of p-cymene), 114.27, 121.15, 122.55, 124.18,
2
0
1
1
9
7
21–122 °C; [α]
.57 (s, 1H, (CH
.12–7.16 (m, 2H, –CH
OPh), 6.08 (d, 1H, J = 5.8 Hz, –CHOH), 4.53–4.56 (m,
, (a)), 4.36–4.41 (m, 1H, NCH , (b)), 4.27 (br, 1H, –CHOH),
.02–4.05 (m, 1H, –CH OPh, (a)), 3.85 (s, 3H, CH N), 3.77–3.81 (m,
-d1, ppm): δ: 36.43
), 67.56, 68.40 (–CHOH and –CH OPh), 114.45,
21.24, 129.54 (o-, m-, p-carbons of –CH OPh), 122.90, 123.28
)NCHN–),158.00 (i-carbon of –CH OPh);
D
= +33.6° (c 1, CHCl
3
); H NMR CDCl
3
-d1, ppm): δ:
3
)NCHN–), 7.41 and 7.33 (2xs, 2H, –NCHCHN–),
2
OPh), 6.82–6.86 (m, 1H, –CH
2
OPh), 6.77–6.79
129.33 (–NCHCHN– and o-, m-, p-carbons of –CH
2
H
OPh), 128.30 (d,
), 134.50 (d,
)NCHN–), 157.18 (i-
); assignment was based
3
2
(
m, 2H, –CH
2
J
J
31P–13C = 10.1 Hz, m-P(C
6
H
5
)
2
), 131.30 (p-P(C
6
)
5 2
1
4
1
H, NCH
2
2
31P–13C = 12.1, o-P(C
6
H
5
)
2
)), 137.78 (-(CH
3
2
3
carbon of –CH
2
OPh), (not observed, i-P(C
6
H )
5 2
1
3
1
13
1
1
31
1
H, –CH
2
OPh, (b)); C NMR (100.6 MHz, CDCl
3
on the H– C HETCOR, DEPT and H– H COSY spectra; P-{ H}
(
CH
3
N), 52.55 (NCH
2
2
NMR (162.0 MHz, CDCl3, ppm): δ 124.61 (s, OPPh
2
); IR: υ 3146, 3056
1
2
(aromatic CeH), 2960, 2870 (aliphatic CeH) 1435 (P-Ph), 1044 (OeP)
−1
(
–NCHCHN–), 137.62 ((CH
3
2
cm ; Anal. for C35
H
40
N
2
O
2
PRuCl
3
(759.12 g/mol): calcd. C 55.38, H
1
13
1
1
assignment was based on the H– C HETCOR, DEPT and H– H
5.31, N 3.69; found C 55.31, H 5.27, N 3.64%.
−
1
COSY spectra; IR: υ 3209 (OeH), 2959 (aliphatic CeH) cm ; Anal. for
6
C
13
H
17
N
2
O
2
Cl (268.74 g/mol): calcd. C 58.10, H 6.38, N 10.42; found C
2.4.4. Synthesis
of
[3-[(2S)-2-({[dichloro(η -benzene)ruthenio]
5
7.99, H 6.34, N 10.37%.
diphenylphosphanyl}oxy)-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium
chloride], (4)
6
2
.4.2. Synthesis of
[3-[(2S)-2-[(diphenylphosphanyl)oxy]-3-
[Ru(η -benzene)(µ-Cl)Cl]
2
(0.055 g, 0.110 mmol) and [(Ph
2
P)-
phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride], (2)
C
13
H
16
N
2
O
2
]Cl, 2 (0.100 g, 0.221 mmol) were dissolved in dry CH
2
Cl
2
3
-[(2S)-2-hydroxy-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium
chloride, (1) (0.100 gr, 0.37 mmol) and Et N (0.038 gr, 0.37 mmol)
were dissolved in dry CH Cl (30 mL) under an argon atmosphere. Next,
PPh
(25 mL) under argon atmosphere and stirred for 1 h at room tempera-
ture. The volume was concentrated to ca. 1–2 mL under reduced pres-
sure and addition of petroleum ether (20 mL) gave the corresponding
ruthenium (II) complex as a red solid. The product was collected by
filtration and dried in vacuo. Yield:138 mg, 88.9%; m.p.:131–132 °C;
3
2
2
2
Cl (0.084 gr, 0.37 mmol) was added dropwise with a syringe to this
solution. The mixture was stirred at room temperature for 30 min, and
the solvent was removed under reduced pressure. After addition of dry
thf, the white precipitate (triethylammonium chloride) was filtered off
under argon and dried in vacuo to produce a white viscous oily com-
2
0
1
[α]
9.26
(C
benzene), 5.11 (br, 1H, -CHOP), 4.60 (br, 2H, NCH
D
= +28.8° (c 1, CHCl
(s, 1H, -(CH
+ –NCHCHN-+–CH
3
); H NMR (400.1 MHz, CDCl3, ppm): δ
3
)NCHN–),
6.63–7.95
(m,
17H,
P
6
H
5
)
2
2
OPh), 5.50 (s, 6H, aromatic protons of
), 3.97 (br, 5H,
-d1, ppm): δ (not ob-
2
0
1
pound 2. Yield: 0.160 g, 95.0%. [α]
D
= +42.5° (c 1, CHCl
-d1, ppm): δ: 9.91 (s, 1H, -(CH
+ –NCHCHN-+–CH
, (a)), 4.62–4.70 (m, 2H, NCH , (b) + -CHOP), 4.17 (m, 2H,
N); C NMR (100.6 MHz, CDCl -d1, ppm): δ
3
); H NMR
2
1
3
(
(
400.1 MHz, CDCl
m, 17H, P(C
3
5
3
)NCHN–), 6.74–7.30
-CH
2
OPh + CH
3
N)); C NMR (100.6 MHz, CDCl
3
6
H
)
2
2
OPh), 4.84–4.87 (m, 1H,
served, CH
3
N), 52.12 (NCH
2
), 67.88 (–CH OPh), 75.32 (d, J = 16.1 Hz,
2
NCH
2
2
-CHOP), 90.49 (s, aromatic carbons of benzene), 114.68, 121.14,
1
3
-
CH
2
OPh), 3.72 (s, 3H, CH
3
2
3
124.62, 124.84, 129.43 (–NCHCHN– and o-, m-, p-carbons of
3
2
3
6.60 (CH
3
N), 52.62 (NCH
), 67.64 (–CH
2
OPh), 78.09 (d, J = 22.1 Hz,
–CH
(C
2
OPh), 128.58 (d,
J
J
31P–13C = 10.1 Hz, m-P(C
6
H
5
2
) ), 131.59 (p-P
-
CHOP), 114.56, 121.35, 122.76, 123.16, 129.61 (–NCHCHN– and o-,
6
H
5
)
2
), 133.38 (d,
31P–13C = 35.2o-P(C
6
5
H )
2
)), 137.69 (-(CH )
3
3
m-, p-carbons of –CH
2
OPh), 128.62 (d, J31P–13C = 9.1 Hz, m-P(C
6
H
5
)
2
),
NCHN–), 157.37 (i-carbon of –CH
2
OPh), (not observed, i-P(C
6
H
5
) );
2
2
1
13
1
1
1
31.53 (p-P(C
6
H
5
)
2
), 135.28 (d, J31P–13C = 12.1, o-P(C
6
H
5
)
2
)), 138.21
assignment was based on the H– C HETCOR, DEPT and H– H
3
1
1
(
(
-(CH
3
)NCHN–), 158.02 (i-carbon of –CH
2
OPh) (not observed, i-P
COSY spectra; P-{ H} NMR (162.0 MHz, CDCl3, ppm): δ 121.85 (s,
1
13
C
6
H
5
)
2
); assignment was based on the H– C HETCOR, DEPT and
OPPh
2
); IR: υ 3142, 3056 (aromatic CeH), 2952 (aliphatic CeH) 1435
1
1
31
1
−1
H– H COSY spectra; P-{ H} NMR (162.0 MHz, CDCl
3
-d1, ppm): δ
(P-Ph), 1044 (OeP) cm ; Anal. for C31
H
32
2
N O
2
PRuCl (703.01 g/
3
1
18.49 (s, OPPh
2
); IR: υ 3146, 3053 (aromatic CeH), 2930, 2870
mol): calcd. C 52.96, H 4.59, N 3.99; found C 52.88, H 4.55, N 3.94%.
−
1
(
aliphatic CeH) 1435 (P-Ph), 1044 (OeP) cm
;
Anal. for
PCl (452.92 g/mol): calcd. C 66.30, H 5.79, N 6.19; found C
6.21, H 5.73, N 6.15%.
5
C
25
H
26
N
2
O
2
2.4.5. Synthesis of [3-[(2S)-2-{[(dichloro(ɳ –pentamethylcyclopentadienyl)
6
iridio)diphenyl phosphanyl]oxy}-3-phenoxypropyl]-1-methyl-1H-imidazol-3-
ium chloride], (5)
6
5
2
.4.3. Synthesis
of
[3-[(2S)-2-({[dichloro(η -p-cymene)ruthenium]
Ir(η -C
5
Me
5
)(μ-Cl)Cl]
2
(0.088 g, 0.110 mmol) and [(Ph
2
P)-
diphenyl phosphanyl}oxy)-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium
C
13
H
16
N
2
O
2
]Cl, 2 (0.100 g, 0.221 mmol) were dissolved in dry CH
2
Cl
2
chloride], (3)
(25 mL) under argon atmosphere and stirred for 1 h at room tempera-
ture. The volume was concentrated to ca. 1–2 mL under reduced pres-
sure and addition of petroleum ether (20 mL) gave the corresponding
Iridium (III) complex as an orange microcrystalline solid. The product
was collected by filtration and dried in vacuo. Yield:160 mg, 85.1%;
6
[
Ru(η -p-cymene)(µ-Cl)Cl]
2
(0.068 g, 0.110 mmol) and [(Ph
2
P)-
C
13
H
16
N
2
O
2
]Cl, 2 (0.100 g, 0.221 mmol) were dissolved in dry CH
2
Cl
2
(
25 mL) under argon atmosphere and stirred for 1 h at room tempera-
ture. The volume was concentrated to ca. 1–2 mL under reduced pres-
sure and addition of petroleum ether (20 mL) gave the corresponding
ruthenium(II) complex as a red solid. The product was collected by
filtration and dried in vacuo. Yield:150 mg, 89.5%; m.p.:127–128 °C;
2
0
1
m.p.:152–153 °C; [α]
CDCl3, ppm): δ 9.72 (s, 1H, -(CH
(C + –NCHCHN-+–CH
J = 17.2 Hz, 2H, NCH ), 4.00 (s, 3H, CH
(a), 3.86 (br, 1H, -CH OPh, (b), 1.33 (s, 15H, CH
NMR (100.6 MHz, CDCl -d1, ppm): δ 8.24 (C Me
50.63 (NCH ), 67.58 (–CH OPh), 74.44 (d, J = 6.0 Hz, -CHOP), 94.12
(C Me ), 114.29, 120.96, 122.67, 123.76, 129.22 (–NCHCHN– and o-,
m-, p-carbons of –CH
131.57 (s, p-P(C
NCHN–), 157.42 (i-carbon of –CH
D
= +46.7° (c 1, CHCl
3
); H NMR (400.1 MHz,
3
)NCHN–), 6.46–7.88 (m, 17H, P
6
H
5
)
2
2
OPh), 5.13 (br, 1H, -CHOP), 4.67 (d,
N), 3.97 (br, 1H, -CH OPh,
of Cp∗(C Me );
), 36.90 (CH N),
2
0
1
[
α]
D
= +39.1° (c 1, CHCl
(s, 1H, -(CH
+ –NCHCHN-+–CH
cymene), 5.16 (d, J = 5.2 Hz, 1H, aromatic protons of p-cymene), 4.93
3
); H NMR (400.1 MHz, CDCl3, ppm): δ
2
2
3
2
1
3
9
.89
3
)NCHN–),
6.42–7.95
(m,
17H,
P
3
5
5
C
(
C
6
H
5
)
2
2
OPh), 5.50 (s, 2H, aromatic protons of p-
3
5
5
3
2
2
(
d, J = 5.2 Hz, 1H, aromatic protons of p-cymene), 4.69 (br, 1H,
5
5
-
CHOP), 4.60 (br, 2H, NCH
2
), 3.95 (br, 4H, -CH
OPh, (b), 2.45 (m, 1H, –CH– of p-cymene), 1.85 (s,
Ph of p-cymene), 1.05 (d, J = 6.8 Hz, 3H, CH CHPh of p-
2
OPh, (a) + CH
3
N),
2
2
OPh), 128.29 (d, J = 11.1 Hz, m-P(C
), 134.67 (br, o-P(C )), 138.37 (-(CH
OPh) (not observed, i-P(C
6
H
5
)
2
3
),
3
.60 (br, 1H, -CH
H, CH
2
6
H
5
)
6
H
5
)
2
)
3
3
3
)
2
2
6
H
5
)
2
);
110

N. Meriç, et al.
Inorganica Chimica Acta 492 (2019) 108–118
3
1
1
Fig. 1. The P-{ H} NMR spectra of compounds [3-[(2S)-2-[(diphenylphosphanyl)oxy]-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride]], (2), [3-[(2S)-2-
6
6
(
{[dichloro(η -p-cymene)ruthenio]diphenyl phosphanyl}oxy)-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride]] (3), [3-[(2S)-2-({[dichloro(η -benzene)ru-
5
thenio]diphenylphosphanyl}oxy)-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride]] (4), [3-[(2S)-2-{[(dichloro(ɳ –pentamethylcyclopentadienyl)iridio)di-
4
phenyl phosphanyl]oxy}-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride]] (5), [3-[(2S)-2-{[(chloro(ɳ -1,5-cyclooctadiene)rhodio)diphenylphosphanyl]
oxy}-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride]] (6).
1
13
1
1
assignment was based on the H– C HETCOR, DEPT and H– H
(25 mL) under argon atmosphere and stirred for 1 h at room tempera-
ture. The volume was concentrated to ca. 1–2 mL under reduced pres-
sure and addition of petroleum ether (20 mL) gave the corresponding
Rhodium (I) complex as a yellow microcrystalline solid. The product
was collected by filtration and dried in vacuo. Yield: 130 mg, 84.2%;
3
1
1
COSY spectra; P-{ H} NMR (162.0 MHz, CDCl3, ppm): δ 94.03 (s,
OPPh ); IR: υ 3056 (aromatic CeH), 2960 (aliphatic CeH) 1435 (P-Ph),
2
−
1
1
044 (OeP) cm ; Anal. for C35
H
41
N
2
O
2
PIrCl (851.27 g/mol): calcd.
3
C 49.38, H 4.85, N 3.29; found C 49.29, H 4.81, N 3.26%.
2
0
1
m.p.:124–125 °C; [α]
D
= +33.2° (c 1, CHCl
3
); H NMR (400.1 MHz,
4
CDCl3, ppm): δ 10.41 (s, 1H, -(CH
3
)NCHN–), 6.84–7.52 (m, 17H, P
2
.4.6. Synthesis of [3-[(2S)-2-{[(chloro(ɳ -1,5-cyclooctadiene)rhodium)
(
6
C H
5
)
2
+ –NCHCHN-+–CH
H, CH of cod), 5.03 (m, 1H, NCH
.57–4.64 (m, 2H, -CH OPh), 4.27 (br, 1H, -CHOP), 3.93 (s, 3H, CH
.42 (br, 1H, CH of cod), 2.96 (br, 1H, CH of cod), 2.38 (br, 2H, CH
2
OPh), 5.76 (br, 1H, CH of cod), 5.69 (br,
(a)), 4.85 (m, 1H, NCH (b)),
N),
of
diphenyl phosphanyl] oxy}-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium
chloride], (6)
1
4
3
2
2
2
3
2
[
Rh(μ-Cl)(cod)]
2
(0.054 g,
0.110 mmol)
and
[(Ph
2
2
P)-
C
13
H
16
N
2
O
2
]Cl, 2 (0.100 g, 0.221 mmol) were dissolved in dry CH
Cl
2
111

N. Meriç, et al.
Inorganica Chimica Acta 492 (2019) 108–118
cod), 2.28 (d, J = 7.2 Hz, 2H, CH
2
of cod), 1.96 (br, 2H, CH
2
of cod),
with 1/2 equivalent of (2) affords only the corresponding monodendate
1
3
6
1
.67 (d, J = 8.0 Hz, 2H, CH
2
of cod) ; C NMR (100.6 MHz, CDCl
3
-d1,
[3-[(2S)-2-({[dichloro(η -p-cymene)ruthenium]diphenyl phosphanyl}
ppm): δ 27.82, 29.08, 32.12, 34.04 (CH
2
of cod), 36.65 (CH
3
N), 50.63
oxy)-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride], (3) as
the main product. Complexation reaction was straightforward, with
coordination to ruthenium being carried out at room temperature. The
initial color change, i.e., from clear orange to deep red [75], attributed
to the dimer cleavage most probably by the functionalized phosphinite
(
NCH
2
), 68.97 (–CH OPh), 71.32 (d, J = 15.1 Hz, CH of cod), 71.81 (d,
2
J = 13.1 Hz, CH of cod), 77.58 (d, J = 12.1 Hz, -CHOP), 111.85 (d,
J = 11.1 Hz, CH of cod), 114.74, 121.49, 122.20, 123.12, 129.76
(
–NCHCHN– and o-, m-, p-carbons of –CH
2
OPh), 128.77 (d,
), 133.18 (d,
)NCHN–), 158.08 (i-carbon of
3
1
1
J = 13.1 Hz, m-P(C
6
H
5
)
2
), 131.65 (s, p-P(C
6
H
5
)
2
ligand based on ionic liquid (FILs-OPPh ). The P-{ H} NMR spectrum
2
J = 15.1 Hz, o-P(C
6
H
5
)
2
)), 138.94 (-(CH
3
is fairly consistent with the structure of 3 showing a single resonance at
1
–
CH
2
OPh) (not observed, i-P(C
6
H
5
)
2
); assignment was based on the
δ 124.61 ppm as shown in Fig. 1. Furthermore, H NMR spectral data of
1
13
1
1
31
1
H– C HETCOR, DEPT and H– H COSY spectra; P-{ H} NMR
compound 3 are consistent with the structure suggested. The signals
consisting of a doublet and two different singlet centered at 5.50, 5.16
and 4.93 ppm are due to the presence of the aromatic protons in the p-
cymene group, this information is complemented by the presence of
1
(
162.0 MHz, CDCl3, ppm):
δ
123.31 (d,
J
(103Rh–31P) = 176.6 Hz,
OPPh
435 (P-Ph), 1044 (OeP) cm
699.46 g/mol): calcd. C 56.67, H 5.48, N 4.05; found C 56.56, H 5.44,
N 4.01%.
2
); IR: υ 3146, 3053 (aromatic CeH), 2937, 2874 (aliphatic CeH)
−1
1
;
Anal. for
C
33
H
38
N
2
O
2
PRhCl
2
(
signals at 2.45 and 1.05, 0.72 ppm due to the CH and CH of the iso-
3
propyl groups of the p-cymene moiety. The p-cymene ligand is parti-
cularly informative with respect to the symmetry of the three legged
fragment. Especially, one of the most available arene ligands in ruthe-
nium chemistry is p-cymene, whose NMR signals are very sensitive to
3
. Results and discussion
6
3.1. Synthesis of the new complexes
the symmetry of organometallic compound. Thus, when it is η -co-
1
13
ordinated to a ML
2
Lꞌ metal fragment (Cs symmetry), the H and
C
6
The reaction of imidazole with epoxide derivatives has been de-
NMR spectra are very different from that of η -coordinated to a ML
1
2
L Lꞌ
scribed [58] and we have also recently reported the preparation of a
fragment (C symmetry) [76,77,78]. Finally, a signal due to the pre-
1
new imidazolium-based phosphinite ionic liquid (IL-OPPh
2
) and its
sence of the methyl in the p-cymene group is observed at 1.85 ppm. In
13 1 31 13
application as reagent for transfer hydrogenation of ketones
a
the C-{ H} NMR spectrum of 3, J( P- C) coupling constants of the
carbons of the phenyl rings were observed (for details see experimental
section), which are consistent with the literature values [79,80,81]. The
[
59,60,61]. The regioselective ring opening of epoxides constitutes one
of the most general methods for synthesis of functionalized imidazole
derivatives [62]. Based on this methodology, here, the reaction be-
tween 1-methylimidazole and (S)-2-oxiranylanisole in ethanol leads to
formation of new 3-[(2S)-2-hydroxy-3-phenoxypropyl]-1-methyl-1H-
imidazol-3-ium chloride, (1) according to a reported procedure [63].
The precipitated product, 1 was filtered and dried in vacuo to obtain it
1
3
1
most relevant signals of C-{ H} NMR spectrum of complex 3 are those
corresponding to p-cymene ligands. Carbon atoms of the arene rings in
p-cymene ligands are observed as four singlets at 94.23, 89.91, 88.26
and 85.29 ppm for complex 3. The structural composition of the com-
plex was also confirmed by IR and elemental analysis. Although, single
crystals of both complexes were obtained by slow diffusion of diethy-
lether into a solution of the compound in dichloromethane over several
days, unfortunately we were not able to protect them from rapid de-
composition in air.
1
as an off-white solid with a good yield (83.0%). The H NMR spectrum
of compound 1 shows characteristic features: the imidazolium ring
protons at δ 9.57 (s, 1H, (CH )NCHN–), 7.41 and 7.33 (2xs, 2H,
3
–
NCHCHN–) ppm. The magnetic non-equivalence of protons as well as
6
carbon atoms of the imidazolium ring (123.28 (–NCHCHN–), 137.62
The reaction of stoichiometric amounts of [Ru(η -benzene)(μ-
(
(CH
3
)NCHN–),158.00 ppm) was also observed. The structure for this
Cl)Cl]
2
and [(Ph
2
PO)
2
-C24
H
16
N ], 2 affords the complex (4) in good
4
compound is consistent with the data obtained from a combination of
multinuclear NMR spectroscopy, IR spectroscopy and elemental ana-
lysis (for details see experimental section and SI). In the next step, [3-
yield as a dark red microcrystalline powder. Ligand 2 was expected to
6
cleave the [Ru(η -benzene)Cl
2
] dimer to give the corresponding (4) via
2
monohapto coordination of the phosphinite group. Complex 4 was
3
1
1
[
(2S)-2-[(diphenylphosphanyl)oxy]-3-phenoxypropyl]-1-methyl-1H-
isolated as indicated by a singlet in the P-{ H} NMR spectrum at δ
imidazol-3-ium chloride], (2) was prepared from the commercially
available starting material chlorodiphenylphosphine and 1, in the
presence of triethylamine [64,65,66]. The evolution of this reaction
121.85 ppm, in line with the values previously observed for similar
1
compounds [82]. Analysis by H NMR reveals this compound to be
diamagnetic, exhibiting signals corresponding to the imidazole ring at
3
1
1
was conveniently monitored by
P-{ H} NMR spectroscopy
9.26 (s, 1H, -(CH
3
)NCHN–), ppm and the C
3
6
H protons as a singlet
6
1
[
67,68,69]. The signals of the starting material PPh
2
Cl at δ 81.0 ppm
5.50 ppm. In the C NMR spectrum of 4, the (-(CH
3
)NCHN–) carbon
disappeared and new singlet appeared downfield at δ 118.49 (s, OPPh
2
)
signal was observed at 137.69 ppm and the C carbon resonance
6 6
H
1
1
3
ppm due to the corresponding phosphinite ligand, in line with the va-
occurred at 90.49 (s) ppm. Furthermore in the C-{ H} NMR spectrum
31 13
lues previously observed for similar compounds [Fig. 1] [70,71,72].
of 4, J( P- C) coupling constants of the carbons of the phenyl rings
1
The appropriate assignment of the H chemical shifts was derived from
was detected, which is consistent with the literature values [83]. In the
1
3
13
1
31 13
2
D HH-COSY spectra and that of the C chemical ones from DEPT and
C-{ H} NMR spectrum, J( P- C) coupling constants of the carbons
2
D HMQC spectra. Furthermore, characteristic J(31P-13C) coupling con-
of the phenyl rings were observed, which are consistent with the lit-
erature values. The structure of 4 was further confirmed by IR spec-
troscopy and microanalysis, and found to be in good agreement with
the theoretical values.
1
3
stants of the carbons of the phenyl ring are observed in the C NMR
spectra (including i-, o-, m-, p- carbons of phenyl rings, for details see
experimental section), which are consistent with the literature values
[
73]. The structure for this ionic based monodendate phosphinite li-
Reactions of the functionalized ionic based monodendate phosphi-
5
gand is also consistent with the data obtained from IR spectrum and
elemental analysis.
2
nite (FILs-OPPh ) with metal [Ir(η -C
5
Me
5
)(μ-Cl)Cl] precursor is also
2
depicted in Scheme 1. Synthesis of compound 5 was achieved by the
5
Because (2) is not stable enough in solution, the Ru(II) complexes 3
and 4 were synthesized in-situ. Reactions of (2) with metal precursors
reaction of ligand (2) with [Ir(η -C
5
Me
5
)(μ-Cl)Cl] in a molar ratio of 2/
2
3
1
1
1 at room temperature for 1 h. In the P-{ H} NMR spectrum, re-
6
6
1
[
Ru(η -p-cymene)(μ-Cl)Cl]
2
6
and [Ru(η -benzene)(μ-Cl)Cl]
2
are depicted
sonance at δ 94.03 ppm may be attributed to complex 5 (Fig. 1). The H
in Scheme 1. Firstly, [Ru(η -p-cymene)(μ-Cl)Cl]
2
was initially chosen as
NMR spectra are consistent with the anticipated structure. Analysis by
1
a starting material, which was prepared from the reaction of the com-
H NMR reveals this compound to be diamagnetic, exhibiting signal
mercially available α-phellandrene(5-isoprophyl-2-methylcyclohexa-
consisting of a singlet centered at 1.33 ppm due to the presence of the
methyl protons in the Cp* group, this information is complemented by
6
1
,3-diene) with RuCl
3
[74]. The reaction of [Ru(η -p-cymene)(μ-Cl)Cl]
2
112

N. Meriç, et al.
Inorganica Chimica Acta 492 (2019) 108–118
Scheme 1. Synthesis of the 3-[(2S)-2-hy-
droxy-3-phenoxypropyl]-1-methyl-1H-imi-
dazol-3-ium chloride, (1), [3-[(2S)-2-[(di-
phenylphosphanyl)oxy]-3-phenoxypropyl]-
1
-methyl-1H-imidazol-3-ium
chloride]],
6
(
2), [3-[(2S)-2-({[dichloro(η -p-cymene)ru-
thenio]diphenyl phosphanyl}oxy)-3-phe-
noxypropyl]-1-methyl-1H-imidazol-3-ium
6
chloride]] (3), [3-[(2S)-2-({[dichloro(η -
benzene)ruthenio]diphenylphosphanyl}
oxy)-3-phenoxypropyl]-1-methyl-1H-imi-
dazol-3-ium chloride] (4), [3-[(2S)-2-{[(di-
5
chloro(ɳ –pentamethylcyclopentadienyl)ir-
idio)diphenyl
phosphanyl]oxy}-
3-
phenoxypropyl]-1-methyl-1H-imidazol-3-
4
ium chloride]] (5), [3-[(2S)-2-{[(chloro(ɳ -
1
,5-cyclooctadiene)rhodio)diphenylpho-
sphanyl]oxy}-3-phenoxypropyl]-1-methyl-
1
H-imidazol-3-ium chloride] (6) (i) 1 equiv.
(
S)-2-Oxiranylanisole,
1
equiv.
HCl,
C
2
H
5
Cl
OH; (ii) 1 equiv. Ph
2
PCl, 1 equiv. Et
3
N,
6
CH
2
2
; (iii) 1/2 equiv. [Ru(η -p-cymene)(µ-
6
Cl)Cl]
2
; (iv) 1/2 equiv. [Ru(η -benzene)(µ-
5
Cl)Cl]2, CH
2
Cl
μ-Cl)Cl]2, CH
cod)]2, CH Cl .
2
; (v) 1/2 equiv. [Ir(η -C
5
5
Me )
(
(
2
2
Cl ; (vi) 1/2 equiv. [Rh(μ-Cl)
2
2
the presence of a signal at 9.72 ppm (-(CH
3
)NCHN–). Furthermore, the
with phosphinite ligand based on functional ionic liquid (FILs) are higly
active in the transfer hdrogenation of ketones. This prompted us to
investigate the asymmetric version of this reaction by using rhodium,
iridium or ruthenium complexes with (CFILs).
1
3
C NMR spectrum of the complex 3 displays a singlet at δ 8.24 ppm
attributable to methyl carbons of Cp* and doublet at δ 94.12 due to
carbons of Cp* ring. We also examined simple coordination chemistry
of [Rh(μ-Cl)(cod)]
2
with ligand (2) . Reactions of [Rh(μ-Cl)(cod)]
2
with
Initially, complexes 3–6 were evaluated as precursors for the cata-
lytic asymmetric transfer hydrogenation of acetophenone by isoPrOH. A
comparison of metal complexes based on chiral fuctionalized ionic li-
quid as precatalysts for the asymmetric hydrogenation of acetophenone
by isoPrOH is summarized in Table 1. Catalytic experiments were car-
ried out under inert (Ar) atmosphere using standard Schlenk-line
techniques. These systems catalyzed the reduction of acetophenone to
corresponding alcohol ((R)-1-phenylethanol) in the presence of KOH.
To an isoPrOH solution of M−CFILs {M: Ru(II), Ir(III), Rh(I)} complex,
an appropriate amount of acetophenone and KOH/isoPrOH solutions
were added, at room temperature. At this temperature, transfer hy-
drogenation of acetophenone occurred very slowly, with low conver-
sion (up to 17%, 24 h) and moderate to high enantioselectivity (up to
86% ee) in the reactions (Table 1, entries 1–4). As a result of the re-
versibility at room temperature, the prolonging the reaction time (96 h)
led to a decreasing of enantioselectivity, as indicated by the catalytic
results collected with catalysts, [86,87]. One typical problem with
transfer hydrogenation reactions (that exploit alcohols as the sacrificial
reductants) is that the initial ee % can be degraded as the reaction is
allowed to proceed to higher conversion. This occurs because oxidation
of (S)-1-phenyl ethanol is thermodynamically favored over reduction
relative to the oxidation of 2-propanol [88] Therefore, we were not
surprised to find that a slight decrease in ee % occurred at higher
conversion with the currently described system [89]. In addition, to
obtain the chiral alcohol in a high yield without significant deteriora-
tion of the enantiomeric purity, the reaction has to be performed with a
substrate concentration as low as 0.1 M and an unnecessarily long ex-
posure of the reaction mixture to the catalyst should be avoided. The
reversibility of these reactions results in ‘back transfer’ of hydrogen
ligand 2 in CH
2
2
Cl in a ratio of 1/2:1 at room temperature for 1 h gave
micro-crystalline precipitate of complex 6. Complexation reactions
were straightforward, with coordination to rhodium being carried out
at room temperature. This ligand was expected to cleave the [Rh(μ-Cl)
(
cod)] dimer to give the corresponding complex via monohapto co-
2
ordination of the phosphinite ligand based ionic liquid (FILs-OPPh
2
).
The coordination of the ligand through the P donor was confirmed by
3
1
1
the P-{ H} NMR spectroscopy. Complex 6 was isolated as indicated
3
1
1
1
by a doublet in the P-{ H} NMR spectrum at δ 123.31 (d,
J
RhP
:
1
76.6 Hz), [84,85] (Fig. 1), indicating that ionic liquid based phos-
1 13
phinite ligand acting as monodendate ligand. H and C NMR spectra
of compound 6 display all the signals of coordinated ligands. The
structural compositions of the complexes 5 and 6 were further con-
firmed by IR spectroscopy and microanalysis, and found to be in good
agreement with the theoretical values (for details see experimental
section).
3.2. Catalytic transfer hydrogenation of ketones
Transfer Hydrogenation method has been extensively studied be-
cause of the low cost and favorable properties of the hydrogen donor as
well as the operational simplicity. However, a problem of the transfer
hydrogenation reaction in isoPrOH is the reversibility of the process.
Not only to overcome this problem, but also to develop highly active
well-designed catalysts, our studies have been continuing and our
group has been reported some metal complexes with phosphinite li-
gands based on ionic liquid in recent years [59,60,61]. Especially, we
have shown that several rhodium, iridium and ruthenium complexes
113

N. Meriç, et al.
Inorganica Chimica Acta 492 (2019) 108–118
Table 1
6
Transfer hydrogenation of acetophenone with 2-propanol catalyzed by [3-[(2S)-2-({[dichloro(η -p-cymene)ruthenium]diphenyl phosphanyl}oxy)-3-phenoxypropyl]-
6
1
-methyl-1H-imidazol-3-ium chloride], (3), [3-[(2S)-2-({[dichloro(η -benzene)ruthenio]diphenylphosphanyl}oxy)-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium
5
chloride]] (4), [3-[(2S)-2-{[(dichloro(ɳ –pentamethylcyclopentadienyl)iridio)diphenyl phosphanyl]oxy}-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride],
4
(5) and [3-[(2S)-2-{[(chloro(ɳ -1,5-cyclooctadiene)rhodio)diphenyl phosphanyl] oxy}-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride]] (6).
O
OH
OH
O
Cat.
*
+
+
Entry
Complex
S/C/KOH
Time
Conversion(%)[c]
% ee[d]
Conf.[e]
TOF(h−1)[f]
[
[
[
[
[
[
[
[
a]
a]
a]
a]
b]
b]
b]
b]
1
2
3
4
5
6
7
8
9
3
4
5
6
3
4
5
6
5
5
5
5
200:1:5
200:1:5
200:1:5
200:1:5
200:1:5
200:1:5
200:1:5
200:1:5
48 h
48 h
48 h
48 h
1 h
15
14
10
21
98
99
99
99
94
98
95
91
68
67
76
86
72
70
80
92
89
92
88
87
R
R
R
R
R
R
R
R
R
R
R
R
< 5
< 5
< 5
< 5
192
196
99
1 h
2 h
1/2h
1/2h
1/2h
1/2h
1/2h
396
376
392
380
364
[
[
[
g]
200:1:3
200:1:5
200:1:7
g]
g]
g]
1
1
1
0
1
2
200:1:9 [
[
a]
[b]
[c]
Reaction conditions: At room temperature; acetophenone/Cat./KOH, 200:1:5;
Refluxing in 2-propanol; acetophenone/Cat./KOH, 200:1:5;
Determined by GC
[
d]
(
three independent catalytic experiments);
Determined by capillary GC analysis using a chiral cyclodex B (Agilent) capillary column (30 m × 0.32 mm
[
e]
I.D. × 0.25 μm film thickness);
Determined by comparison of the retention times of the enantiomers on the GC traces with the literature values, (R) configuration
[
f]
−1 [g]
was obtained in all experiments;
TOF = (mol product/mol Cat.) × h
;
Refluxing in 2-propanol.
Fig. 2. Equilibria between the kinetic and thermodynamic products (R is aryl).
(
from the enantioenriched alcohol) to the generated ketone as depicted
9–12). In addition, replacing KOH with NaOH slightly decreased both
the reaction rate and enantioselectivity. A control experiment in the
absence of base did not lead to meaningful conversion (< 3%). As seen
from Table 1, the higher conversion and ee % obtained for initial re-
duction of acetophenone motivated us to keep employing (6). These
results clearly indicate that the skeleton of the ligands and the fragment
attached to the Rhodium(I) center are responsible for the high con-
version (up to 98%) and enantioselectivity (up to 92 ee %).
in Fig. 2. However, the extent of degradation of enantiomeric purity
was only found to be at approximately 4% when the reaction times
were extended from 48 to 96 h for the various case. As such the reac-
tions were not allowed to reach full conversion, and data were acquired
for all cases at 48 h [90]. As seen from Table 1, the reactions proceeded
to give (R)-1-phenyl ethanol in 10–21% conversion with 67–86% ee’s
after stirring at room temperature for 48 h. An increase in the reaction
time to 96 h resulted in 19–43% conversion with 62–83% ee’s. Due to
the reversibility at room temperature, the prolonging the reaction time
led to a slight decrease in enantioselectivity.
The catalytic reduction of acetophenone derivatives were conducted
with a substrate/catalyst molar ratio (S/C) of 200 using 0.05 M solution
in isoPrOH. Examples of the asymmetric reaction of acetophenone de-
rivatives with the complexes are listed in Table 2. The rate and ste-
reoselectivity are delicately influenced by reaction conditions as well as
steric and electronic properties of the substituents of the ketones. As
seen from Table 2, aromatic ketones are hydrogenated with high en-
antioselectivity and the same mode face selection. One can easily see
from the results that a range of acetophenone derivatives can be hy-
drogenated from good to high enantioselectivities. It is well-known that
the introduction of electron withdrawing substituents to the aryl ring of
the ketone decreases the electron density of the C]O bond so that the
activity was improved resulting in easier hydrogenation [91]. Thus, the
When the reactions were carried out at 82 °C, all catalysts showed
satisfying catalytic activities (up to 396 TOF values) and enantioselec-
tivities since almost conversions to the total corresponding alcohol were
observed (Table 1, entries 5–8). Although the lower reaction tempera-
tures should have a beneficial effect on the enantioselectivities, higher
asymmetric inductions (70–92% ee’s) were observed at 82 °C. This may
attributed to the shorter reaction times and these results indicate that
the reaction temperature plays an important role on the catalytic ac-
tivity and enantioselectivity. Furthermore, the complexes were very
active catalysts, leading to quantitative conversions of (R)-1-phenyl
ethanol with a catalyst/base ratio of 1:5. Increase or decrease of the
base:Cat. ratio from 5:1 to 9:1 or 3:1 slightly decreased the reaction rate
with a slight loss of enantiomeric purity of the product (Table 1, entries
introduction of electron-withdrawing substituents, such as CF
3
or NO ,
2
to the aryl ring of the ketone, resulted in improved activity with good
enantioselectivity (Table 2, entries 1–16). On the contrary, the
114

N. Meriç, et al.
Inorganica Chimica Acta 492 (2019) 108–118
Table 2
6
Transfer hydrogenation results for substituted acetophenones with the catalyst systems prepared from [3-[(2S)-2-({[dichloro(η -p-cymene)ruthenium]diphenyl
6
phosphanyl}oxy)-3-phenoxypropyl]-1-methyl-1H-imidazol-3-ium chloride], (3), [3-[(2S)-2-({[dichloro(η -benzene)ruthenio]diphenylphosphanyl}oxy)-3-phenox-
5
ypropyl]-1-methyl-1H-imidazol-3-ium chloride]] (4), [3-[(2S)-2-{[(dichloro(ɳ –pentamethylcyclopentadienyl)iridio)diphenyl phosphanyl]oxy}-3-phenoxypropyl]-
4
1
-methyl-1H-imidazol-3-ium chloride], (5) and [3-[(2S)-2-{[(chloro(ɳ -1,5-cyclooctadiene)rhodio)diphenyl phosphanyl] oxy}-3-phenoxypropyl]-1-methyl-1H-imi-
a]
dazol-3-ium chloride]] (6).
O
OH
OH
O
Cat.
*
R
R
+
+
Entry
Cat.
Substrate
Product
Time
Conv.(%)[b]
% ee[c]
TOF(h−1)[d]
Config.[e]
1
3
O
OH
20 min
98
63
588
R
O
2
N
O
2
N
2
3
4
5
4
5
6
3
20 min
45 min
10 min
45 min
99
97
99
99
65
76
86
65
594
259
1188
264
R
R
R
R
CF3
CF3
O
OH
6
7
8
9
4
5
6
3
45 min
3/2 h
99
98
98
98
66
78
85
61
264
131
588
392
R
R
R
R
20 min
30 min
O
OH
3
F C
F3C
1
1
1
1
0
1
2
3
4
5
6
3
30 min
1 h
97
99
99
99
60
71
84
58
388
198
792
792
R
R
R
R
15 min
15 min
O
OH
3
F C
F3C
1
1
1
1
4
5
6
7
4
5
6
3
15 min
30 min
10 min
8 h
99
97
99
99
57
70
82
72
792
388
1188
25
R
R
R
R
OCH3
O
OCH3 OH
1
1
2
2
8
9
0
1
4
5
6
3
8 h
98
99
98
97
73
84
93
60
25
14
39
39
R
R
R
R
14 h
5 h
O
OH
5 h
H CO
H CO
3
3
2
2
2
2
2
3
4
5
4
5
6
3
5 h
8 h
3 h
3 h
99
99
98
98
62
69
80
53
40
25
65
65
R
R
R
R
O
OH
3
H CO
3
H CO
2
2
2
6
7
8
4
5
6
3 h
99
98
99
50
62
75
66
R
R
R
6 h
33
3/2h
132
(
continued on next page)
115

N. Meriç, et al.
Inorganica Chimica Acta 492 (2019) 108–118
Table 2 (continued)
Entry
Cat.
Substrate
Product
Time
6 h
Conv.(%)[b]
98
% ee[c]
TOF(h−1)[d]
33
Config.[e]
2
9
3
CH3
CH3
67
R
O
OH
3
3
3
3
0
1
2
3
4
5
6
3
6 h
97
99
98
99
66
78
87
57
32
20
65
40
R
R
R
R
10 h
3 h
O
OH
5 h
H C
3
H C
3
3
3
3
3
4
5
6
7
4
5
6
3
5 h
8 h
2 h
3 h
99
97
98
98
55
64
81
50
40
24
98
65
R
R
R
R
O
OH
3
H C
H C
3
3
3
4
8
9
0
4
5
6
3 h
6 h
1 h
99
98
98
49
57
70
66
R
R
R
33
196
Reaction conditions: [ Catalyst (0.00125 mmol), substrate (0.25 mmol), 2-propanol (5 mL), KOH (0.0625 mmol %), 82 °C, the concentration of acetophenone de-
a]
[
b]
[c]
rivatives are 0.05 M;
Purity of compounds is checked by NMR and GC (three independent catalytic experiments), yields are based on aryl ketone; Determined by
[
d]
−1
capillary GC analysis using a chiral cyclodex B (Agilent) capillary column (30 m × 0.32 mm I.D. × 0.25 μm film thickness);
TOF = (mol product/mol Cat.) × h
;
[
e]
Determined by comparison of the retention times of the enantiomers on the GC traces with literature values, (R) configuration was obtained in all experiments.
Table 3
4
Transfer hydrogenation of various ketones with 2-propanol catalyzed [3-[(2S)-2-{[(chloro(ɳ -1,5-cyclooctadiene)rhodio)diphenyl phosphanyl] oxy}-3-phenox-
[
a]
ypropyl]-1-methyl-1H-imidazol-3-ium chloride], (6).
O
OH
OH
O
Cat.
+
+
R1
R2
R
1
*
R
2
Entry
Cat.
R
1
R
2
Time
Conv.(%)[b]
ee(%)[c]
TOF(h−1)[d]
Conf.[e]
1
2
3
4
5
6
7
8
6
6
6
6
6
6
6
6
CH
CH
CH
CH
CH
CH
CH
3
3
3
3
3
3
3
CH
2
2
CH
3
2
)
1 h
98
99
98
97
99
97
98
98
90
84
83
81
96
79
70
77
196
132
55
R
R
R
R
R
R
R
R
CH
CH
C
6
2
H
5
3/2h
4 h
CH(CH
3
CH
2
CH(CH
3
)
2
3 h
65
1-naphthyl
3/4h
5/2h
3/2h
3 h
264
78
n-C
4
11
11
H
9
C
6
6
H
131
65
6 5
C H
C
H
Reaction conditions:[a] Catalyst (0.00125 mmol), substrate (0.25 mmol), 2-propanol (5 mL), KOH (0.00625 mmol %), 82 °C, the concentration of acetophenone de-
[
b]
[c]
rivatives are 0.05 M;
Purity of compounds is checked by NMR and GC (three independent catalytic experiments), yields are based on aryl ketone; Determined by
[
d]
−1
capillary GC analysis using a chiral cyclodex B (Agilent) capillary column (30 m × 0.32 mm I.D. × 0.25 μm film thickness);
TOF = (mol product/mol Cat.) × h
;
[
e]
Determined by comparison of the retention times of the enantiomers on the GC traces with literature values, (S) or (R) configuration was obtained in all
experiments.
introduction of an electron-donating group such as methyl or methoxy
group tends to lower the rate with nearly similar enantioselectivities
stereoselectivity are delicately affected by the bulkiness and electronic
properties of the alkyl group and aryl substituent. With the using
complex 6 as catalyst, the reaction of methyl/alkyl and methyl/aryl
ketones gave the chiral alcoholic products in an acceptable chemical
yield and enantiomeric purity. Primarily, we carried out further ex-
periments to study the influence of bulkiness of the alkyl groups on the
catalytic activity and selectivity (Table 3, entries 1–4). For this aim, a
variety of simple methyl/steric-alkyl ketones were transformed to the
corresponding secondary alcohols, and it was found that the activity
and selectivity are highly dependent on the steric hindrance of the alkyl
group. As seen from Table 3, reaction of methyl/steric-alkyl ketones
possessing a bulky alkyl substituent proceeded rather sluggish and led a
decrease in enantioselectivity. As the bulkiness of the alkyl group
(
Table 3, entries 17–40). It can be seen from Table 2, ortho-substituted
acetophenones can dramatically increase the enantioselectivity, while
meta- and para- substitution to acetophenones have detrimental effect.
As expected, the lowest enantioselectivity was observed in transfer
hydrogenation of p-methoxyacetophenone, whereas the highest one
was found in that of o-methoxyacetophenone (93% ee) [92].
Due to the efficiency in higher enantioselectivity (approximately 12
ee%) of (6) in the transfer hydrogenation of aromatic ketones, a variety
of simply aryl alkyl (S/C = 200) can be transformed to the corre-
sponding secondary alcohols with high enantiomeric purity under the
optimization conditions, as exemplified in Table 1. The rate and
116

N. Meriç, et al.
Inorganica Chimica Acta 492 (2019) 108–118
increases from ethyl to secbutyl, the extent of enantioselectivity lowers.
Indeed, lower activity and enantioselectivity were obtained in case of
methyl secbutyl ketone (81% ee, TOF: 65) as expected (Table 3, entry 4)
[23] A.N. Collins, G.N. Sheldrake, J. Crosby (Eds.), Chirality in industry: The commer-
cial.
[
[
24] V. Turcry, C. Pasquier, F. Agbossou-Niedercorn, C. R. Chimie 6 (2003) 179–184.
25] R.A.W. Johnstone, A.H. Wilby, I.D. Entwistle, Chem. Rev. 85 (1985) 129–170.
[
93]. Furthermore, as seen from Table 3, the best result in terms of
[26] M. Yiğit, B. Yiğit, I. Özdemir, E. Çetinkaya, B. Çetinkaya, Appl. Organometal. Chem.
2
0 (2006) 322–327.
enantioselectivity was observed with 1-naphtyl methyl ketone. In that
case, high TOF value (TOF: 264) and the highest enantioselectivity, up
to 96% ee, were obtained for catalyst (6). In addition, the hydrogena-
tion of ketones including cyclohexyl group was very slow and the en-
antioselectivities were incredible lower (Table 3, entries 7–8).
[
[
27] R. Noyori, M. Yamakawa, S. Hashiguchi, Acc. Chem. Res. 23 (1990) 345–350.
28] S. Ram, R.E. Ehrenkaufer, Synthesis (1988) 91–95.
[29] M. Aydemir, N. Meriç, C. Kayan, F. Ok, A. Baysal, Inorg. Chim. Acta 398 (2013)
1–10.
[
[
30] A.N. Ajjou, J.-L. Pinet, J. Mol. Catal. A Chem. 214 (2004) 203–206.
31] Y.-Y. Li, H. Zhang, J.-S. Chen, X.-L. Liao, Z.-R. Dong, J.-X. Gao, J. Mol. Catal. A
Chem. 218 (2004) 153–156.
4
. Conclusions
[32] T. Welton, Chem. Rev. 99 (1999) 2071–2084.
[
[
[
33] K.R. Seddon, J. Chem. Technol. Biotechnol. 68 (1997) 351–356.
34] H. Carmichael, Chem. Br. 1 (2000) 36–38.
Several catalytic systems with metal complexes based on CFILs for
35] Y. Chauvin, H. Olivier, Chemtech 25 (1995) 26–30.
asymmetric transfer hydrogenation of prochiral ketones have now
reached high levels of efficiency in term of activity and enantioselec-
tivity. High conversion and enantioselectivity were obtained in the
catalytic reaction. The high catalytic activity and enantioselectivity for
this kind of ligands show great potential for further exploring similar
system and achieving outstanding stereoselectivity for a wider scope of
ketone substrates. Furthermore, the simplicity and efficiency clearly
make it an excellent choice of catalyst for the practical preparation of
highly valued alcohols via catalytic asymmetric transfer hydrogenation
of ketones. Further studies are in progress to explain the improvement
of both activity and enantioselectivity related to this CFILs group and to
extend the use of these new phosphinite ligands in other asymmetric
catalytic reactions.
[36] R.T. Carlin, J.S. Wilkes, Advances in Nonaqueous Chemistry, Wiley-VCH, New York,
1
994.
[
[
37] M. Freemantle, Chem. Eng. News 78 (2000) 37-50 and 77 (1999) 23-24.
38] S.V. Malhotra, H. Zhao, Phys. Chem. Liquid 42 (2004) 215 215.
[39] Y. Xiao, S.V. Malhotra, J. Organomet. Chem. 690 (2005) 3609–3613.
[
40] P. Nockemann, M. Pellens, K. Van Hecke, L. Van Meervelt, J. Wouters, B. Thijs,
E. Vanecht, T.N. Parac-Vogt, H. Mehdi, S. Schaltin, J. Fransaer, S. Zahn, B. Kirchner,
K. Binnemans, Chem. Eur. J. 16 (2010) 1849–1858.
[41] C. Chiappe, C.S. Pomelli, U. Bardi, S. Caporali, Phys. Chem. Chem. Phys. 14 (2012)
5
045–5051.
[
[
42] K.L. Luska, A. Moores, Adv. Synth. Catal. 353 (2011) 3167–3177.
43] J. Andrieu, L. Harmand, M. Picquet, Polyhedron 29 (2010) 601–605.
[44] K.L. Luska, K.Z. Demmans, S.A. Stratton, A. Moores, Dalton. Trans. 41 (2012)
13533–13540.
[
[
45] C. Barthes, C. Lepetit, Y. Canac, C. Duhayon, D. Zargarian, R. Chauvin, Inorg. Chem.
5
2 (2013) 48–58.
46] D.J. Brauer, K. Kottsieper, C. Liek, O. Stelzer, H. Waffenschmidt, P. Wasserscheid, J.
Organomet. Chem. 630 (2001) 177–184.
[
[
47] Y. You, Y. Wang, X. Zhao, S. Chen, Y. Liu, Organometallics 32 (2013) 2698–2704.
48] S. Chen, Y. Wang, W. Yao, X. Zhao, Y. Liu, J. Mol. Catal. A: Chem. 378 (2013)
Acknowledgements
2
93–298.
Partial supports of this work by Dicle University Research Fund,
Turkey (Project numbers: FEN.17.019 and FEN.17.023) and Kazakh-
British Technical University, Research Fund Kazakhstan (IRN:
AP05132833, BR05236800) is gratefully acknowledged.
[49] X. Wang, Y. Wang, J. Zhang, X. Zhao, Y. Liu, J. Organomet. Chem. 762 (2014)
4
0–47.
[
50] a) B. Ak, D. Elma, N. Meriç, C. Kayan, U. Işık, M. Aydemir, F. Durap, A. Baysal,
Tetrahedron: Asymmetry 24 (2013) 1257-1264; b) B. Ak, M. Aydemir, Y. S. Ocak, F.
Durap, C. Kayan, A. Baysal, H. Temel, Inorg. Chim. Acta 409 (2014) 244-253; c) M.
Aydemir, A. Baysal, E. Şahin, B. Gümgüm. S. Özkar, Inorg. Chim. Acta 378(2011)
1
0-18; d) M. Aydemir, N. Meric, A. Baysal, C. Kayan, M. Toğrul, B, Gümgüm, Appl.
Appendix A. Supplementary data
Organomet. Chem. 24 (2010) 215-221; e) S. Baturay, A. Tombak, D. Kaya, Y. S.
Ocak, M. Tokuş, M. Aydemir, T. Kılıçoğlu, J Solgel Sci Technol. 72(2) (2016) 422-
4
29; f) K. Rafikova, N. Kystaubayeva, M. Aydemir, C. Kayan, Y.S. Ocak, H. Temel,
Supplementary data to this article can be found online at https://
doi.org/10.1016/j.ica.2019.04.016.
A. Zazybin, N. Gurbuz, ,İ Ozdemir, J. Organomet. Chem. 758 (2014) 1-8.
51] M. Aydemir, F. Durap, A. Baysal, N. Meriç, A. Buldağ, B. Gümgüm, S. Özkar,
L.T. Yildirim, J. Mol. Catal A. Chem. 326 (2010) 75–81.
[
[
[
[
52] B. Ak, F. Durap, M. Aydemir, A. Baysal, Appl. Organomet. Chem. 29 (2015)
References
7
64–770.
53] F. Durap, D.E. Karakaş, B. Ak, A. Baysal, M. Aydemir, J. Organomet. Chem. 818
(2016) 92–97.
[
[
[
1] M.D. Rudd, M.A. Creighton, J.A. Kautz, Polyhedron 23 (2004) 1923–1929.
2] K.G. Gaw, M.B. Smith, J.W. Steed, J. Organomet. Chem. 664 (2002) 294–297.
3] F. Agbossou, J.-F. Carpentier, F. Hopiot, I. Suisse, A. Mortreux, Coord. Chem. Rev.
54] a) M.A. Bennet, A.K. Smith, J. Chem. Soc., Dalton Trans. (1974) 233–241;
b) M.A. Bennet, T.N. Huang, T.W. Matheson, A.K. Smith, Inorg. Synth. 21 (1982)
1
78–180 (1998) 1615–1645.
7
4–78.
[
4] M.R. Zuburi, H.L. Milton, A.M.Z. Slawin, J.D. Woollins, Polyhedron 23 (2004)
[55] R.A. Zelonka, M.C. Baird, J. Organomet. Chem. 35 (1972) C43–C46.
8
65–868.
[56] C. White, A. Yates, P.M. Maitlis, M. Heinekey, Inorg. Synth. 29 (1992) 228–234.
[
[
[
5] H.J. Kreuzfelt, C. Döbler, J. Mol. Cat. A: Chem. 136 (1998) 105–110.
6] F. Agbossou-Niedercorn, I. Suisse, Coord. Chem. Rev. 242 (2003) 145–158.
7] R.H. Crabtree, The Organometallic Chemistry of the Transition Metals, Wiley-
Interscience, New York, 2001.
[
57] G. Giordano, R.H. Crabtree, Inorg. Synth. 28 (1990) 88–90.
[58] G. Cooper, W.J. Irwin, J. Chem. Soc., Perkin Trans. 1 (1976) 545–549.
[
[
59] D.E. Karakaş, F. Durap, A. Baysal, Y.S. Ocak, K. Rafikova, E.C. Kaya, A. Zazybin,
H. Temel, C. Kayan, N. Meriç, M. Aydemir, J. Organomet. Chem. 824 (2016) 25–32.
60] N. Meriç, M. Aydemir, U. Işık, Y. S. Ocak, K. Rafikova, S. Paşa, C. Kayan, F.
Durap, A.
[
[
8] M. Haiharasarma, C.H. Lake, C.L. Watkins, G.M. Gray, J. Organomet. Chem. 580
(
1999) 328–338.
9] P. Bergamini, V. Bertolasi, F. Milani, Eur. J. Inorg. Chem. (2004) 1277–1284.
[61] M. Aydemir, K. Rafikova, N. Kystaubayeva, S. Paşa, N. Meriç, Y.S. Ocak, A. Zazybin,
H. Zazybin, H. Temel, Appl. Organomet. Chem. 28 (11) (2014) 818–825.
[
[
[
[
10] G.D. Cuny, S.L. Buchwald, J. Am. Chem. Soc. 115 (1993) 2066–2068.
11] Z. Csok, G. Szalontai, G. Czira, L. Kollar, J. Organomet. Chem. 570 (1998) 23–29.
12] P.W. Galka, H –B. Kraatz,, J. Organomet. Chem. 674 (2003) 24–31.
13] H.B. Kagan, M. Sasaki, Transition Metals for Organic Synthesis, Wiley-VCH,
Weinheim, 1998.
[62] A. Allegue, M. Albert-Soriano, I.M. Pastor, Appl. Organometal. Chem. 29 (2015)
6
24–632.
[63] J.D. Holbrey, M.B. Turner, W.M. Reichert, R.D. Rogers, Green Chem. 5 (2003)
731–736.
[
[
[
[
[
14] J-.H-. Xie, Q-.L-. Zhou, Acc. Chem. Res. 41 (5) (2008) 581–593.
15] O. Pamies, J.-E. Backvall, Chem. Eur. J. 23 (7) (2001) 5052–5058.
16] M.T. Miller, P.K. Gantzel, T.B. Karpishin, Inorg. Chem. 38 (1999) 3414–3422.
17] G. Venkatachalam, R. Ramesh, Inorg. Chem. Commun. 9 (2006) 703–707.
18] N. Meriç, C. Kayan, M. Aydemir, Y.S. Ocak, A. Baysal, H. Temel, Dicle Univ. J. Inst.
Sci. Tech. 2 (2013) 1–8.
[
[
64] M. Aydemir, A. Baysal, F. Durap, B. Gümgüm, S. Özkar, L.T. Yıldırım, Appl.
Organomet. Chem. 23 (2009) 467–475.
65] M. Aydemir, N. Meric, A. Baysal, B. Gümgüm, M. Toğrul, Y. Turgut, Tetrahedron:
Asymmetry 21 (2010) 703–710.
[66] U. Işık, M. Aydemir, N. Meriç, F. Durap, C. Kayan, H. Temel, A. Baysal, J. Mol.
Catal. A: Chem. 379 (2013) 225–233.
[
19] C. Kayan, N. Meriç, M. Aydemir, A. Baysal, H. Temel, Dicle Univ. J. Inst. Sci. Tech. 2
[67] D. Franco, M. Gomez, F. Jimenez, G. Muller, M. Rocamora, M.A. Maestro, J. Mahia,
Organometallics 23 (2004) 3197–3209.
(
2013) 20–27.
[
[
20] R. Malacea, R. Poli, E. Manoury, Coord. Chem. Rev. 254 (2010) 729–752.
21] H.U. Blaser, E. Schmidt (Eds.), Large scale Asymmetric Catalysis, Wiley-VCH,
Weinheim, 2003.
[68] M.S. Balakrishna, R. McDonald, Inorg. Chem. Commun. 5 (2002) 782–786.
[
69] P. Bergamini, V. Bertolasi, M. Cattabriga, V. Ferretti, U. Loprieno, N. Mantovani,
L. Marvelli, Eur. J. Inorg. Chem. (2003) 918–925.
[
22] H. U. Blaser, F. Spindler, M. Thommen, Industrial Applications. in: J. G. deVries, C.
J. Elsevier (Eds.), Handbook of Homogeneous Hydrogenation, Wiley-VCH,
Weinheim, 2007, pp. 1279-1326.
[70] E. Hauptman, R. Shapiro, W. Marshall, Organometallics 17 (1998) 4976–4982.
[
71] K. Ruhlan, P. Gigler, E. Herdweck, J. Organomet. Chem. 693 (2008) 874–893.
[72] G. Esquius, J. Pons, R. Yanez, J. Ros, R. Mathieu, B. Donnadieu, N. Lugan, Eur. J.
117

N. Meriç, et al.
Inorganica Chimica Acta 492 (2019) 108–118
Inorg. Chem. (2002) 2999–3006.
73] F. Majoumo, P. Lönnecke, O. Kühl, E. Hey-Hawkins, Z. Anorg, Allg. Chem. 630
(1998) 2279–2284.
[
[84] H.L. Milton, M.V. Wheatley, A.M.Z. Slawin, Polyhedron 23 (2004) 3211–3220.
[85] Q. Zhang, G. Hua, P. Bhattacharyya, A.M.Z. Slawin, J.D. Woollins, J. Chem. Soc.,
Dalton Trans. (2003) 3250–3257.
(
305) (2004) 308.
[
[
74] M.A. Bennet, G.B. Robertson, A.K. Smith, J. Organomet. Chem. 43 (1972) C41–C43.
75] A.M. Maj, K.M. Pietrusiewicz, I. Suisse, F. Agbossou, A. Mortreux, Tetrahedron:
Asymmetry 10 (1999) 831–835.
[86] K.-J. Haack, S. Hashiguchi, A. Fujii, T. Ikariya, R. Noyori, Angew. Chem., Int. Ed.
Engl. 36 (1997) 285–288.
[
76] A. Caballero, F.J. Jalon, B. Manzano, G. Espino, M. Perez-Manrique, A. Mucientes,
F.J. Poblete, M. Maestro, Organometallics 23 (2004) 5694–5706.
[87] T. Ikariya, A.J. Blacker, Acc. Chem. Res. 40 (2007) 1300–1308.
[88] J.M. Keith, J.F. Larrow, E.N. Jacobsen, Adv. Synth. Catal. 343 (2001) 5–26.
[89] J.W. Faller, A.R. Lavoie, Organometallics 20 (2001) 5245–5247.
[90] S. Hashiguchi, A. Fujii, J. Takehara, T. Ikariya, R. Noyori, J. Am. Chem. Soc. 117
(1995) 7562–7563.
[
[
77] H. Yang, N. Lugan, R. Mathieu, An. Quim Int. Ed. 93 (1997) 28–38.
78] E. de la Encarnacion, J. Pons, R. Yanez, J. Ros, Inorg. Chim. Acta 358 (2005)
3
272–3276.
[
[
[
[
[
79] D. Morales-Morales, R. Redon, C. Yung, C.M. Jensen, Chem. Commun. (2000)
619–1620.
80] E. Lindler, M. Mohr, C. Nachtigal, R. Favzi, G. Henkel, J. Organomet. Chem. 595
[91] İ. Özdemir, S. Yaşar, Trans. Met. Chem. 30 (2005) 831–835.
[92] J. Takehara, S. Hashiguchi, A. Fujii, S. Inoue, T. Ikariya, R. Noyori, J. Chem. Soc.,
Chem. Commun. (1996) 233–234.
1
(
2000) 166–177.
[93] a) J.-X. Gao, H. Zhang, X.-D. Yi, P.-P. Xu, C.-L. Tang, H.-L. Wan, K.-R. Tsai,
T. Ikariya, Chirality 12 (2000) 383–388;
81] O. Akba, F. Durap, M. Aydemir, A. Baysal, B. Gümgüm, S. Özkar, J. Organomet.
Chem. 694 (5) (2009) 731–736.
b) J.-S. Chen, Y.-Y. Li, Z.-R. Dong, B.-Z. Li, J.-X. Gao, Tetrahedron Lett. 45 (2004)
8415–8418;
82] R. Tribo, S. Munoz, J. Pons, R. Yanez, A. Alvarez-Larena, J.F. Piniella, J. Ros, J.
Organomet. Chem. 690 (2005) 4072–4079.
c) Z.-R. Dong, Y.-Y. Li, J.-S. Chen, B.-Z. Li, Y. Xing, J.-X. Gao, Org. Lett. 7 (6)
(2005) 1043–1045.
83] P. Le Gendre, M. Offenbecher, C. Bruneau, P.H. Dixneuf, Tetrahedron: Asymmetry 9
118