The application of novel boron complexes in asymmetric transfer hydrogenation of aromatic ketones

Article abstract of DOI:10.1016/j.tetasy.2015.08.007

Asymmetric transfer hydrogenation using iso-PrOH as a hydrogen source offers an attractive route for reducing simple unsymmetrical functionalized ketones to chiral alcohols. The combined use of organometallic and coordination chemistry has produced a numb

Full text of DOI:10.1016/j.tetasy.2015.08.007

Tetrahedron: Asymmetry 26 (2015) 1058–1064
Contents lists available at ScienceDirect
Tetrahedron: Asymmetry
journal homepage: www.elsevier.com/locate/tetasy
The application of novel boron complexes in asymmetric transfer
hydrogenation of aromatic ketones
b,d,
⇑
, Salih Pa ßs a a,b, Murat Aydemir b,c
Hamdi Temel
a
Department of Chemistry, Faculty of Education, University of Dicle, 21280 Diyarbakir, Turkey
Science and Technology Application and Research Center (DUBTAM), Dicle University, Diyarbakir 21280, Turkey
Department of Chemistry, Faculty of Science, University of Dicle, 21280 Diyarbakir, Turkey
b
c
d
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Dicle University, TR-21280 Diyarbakir, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
Asymmetric transfer hydrogenation using iso-PrOH as a hydrogen source offers an attractive route for
reducing simple unsymmetrical functionalized ketones to chiral alcohols. The combined use of
organometallic and coordination chemistry has produced a number of new and powerful synthetic
methods for important classes of compounds in general and for optically active substances in particular.
For this aim, the (S,Z)-1-((1-hydroxy butane-2-yl imino)methyl)naphthalene-2-ol chiral ligand was cho-
sen to obtain boron complexes. Boronic derivative compounds such as phenylboronic acid, 6-methoxy-
naphthalen-2-ylboronic acid, 4-methyl-3-nitrophenylboronic acid and 1,4-phenylenediboronic acid
were applied to obtain complexation with chiral based ligands. The structures of these ligands
and their complexes have been elucidated by a combination of multinuclear NMR spectroscopy,
LC–MS/MS, TGA/DTA, UV–Vis., elemental analysis, XRD, SEM, and FTIR. These boron complexes have also
been tested as catalysts in the enantioselective transfer hydrogenation of acetophenone derivatives to
afford the corresponding product, (S)-1-phenylethanol with high conversions (up to 99%) and modest
enantioselectivities (up to 70% ee). The substituents on the backbone of the ligands had a significant
effect on both the activity and % ee.
Received 26 June 2015
Accepted 13 August 2015
Available online 24 September 2015
Ó 2015 Elsevier Ltd. All rights reserved.
1
. Introduction
obtain various structures.12,3,4,9,13,14 In addition, since boron has a
similar atomic size to carbon, it allows us to investigate alloying
1
5
Boronic acids and derivatives are rarely found in Nature and
experiments on the hydrogenation properties of TiFe. Biological
research has also increased over last few decades due to its appli-
cation in cancer treatment. Boron neutron capture therapy is a
common treatment, but it still requires development besides its
these compounds, which can be classified as abiotic, are obtained
synthetically from primary sources of boron. They can be obtained
via acidification of borax with carbon dioxide. Boronic acid deriva-
tives are generally synthesized from borate esters, which are
mainly known as precursors of the process.1 The simple dehydra-
1
6,17,10
significant effect on cancer cells.
Previous surveys have
–4
claimed that boron deficiency has caused a decrease in plant
growth because of its important role in photosynthesis. The
presence of coordinative B N and covalent B–O bonds makes
the structure stable in air.
5
tion of boric acid with various alcohols gives borate esters. The
mild Lewis acidity, attenuated reactivity behavior, and ease of
handling without toxicity make boronic acid a favorable class of
synthetic intermediates. Since boronic acids are environmentally
friendly, they can be regarded as green.5
The widespread use of boron based organic and inorganic com-
pounds has increased over many years, due to their applicability in
textiles, medicinal chemistry, pharmaceutical studies, agriculture,
Homogeneous asymmetric catalysis with transition metal com-
–10
18
plexes is an active area of research and great interest has been
directed toward the design and development of efficient ligands.19
An increasing number of chiral compounds and enantiomerically
pure drugs are prepared via transition metal-catalyzed asymmetric
5
,11
20
and industry.
Although boron is a semi-metal, it can demon-
reactions. Since the reactivity and stereoselectivity of asymmet-
strate complexation ability due to its electron deficient nature.
Thus O, N, P and also S atoms can coordinate to a boron atom to
ric transformations are highly dependent on the structure of the
chiral ligand coordinated to the transition metal, the design and
synthesis of efficient chiral ligands are important and have
attracted a great deal of attention from both academia and indus-
⇑
Corresponding author. Tel.: +90 412 248 8550x3966; fax: +90 412 248 8300.
E-mail address: htemel@dicle.edu.tr (H. Temel).
2
1–23
try.
Asymmetric transfer hydrogenation using 2-propanol as a
http://dx.doi.org/10.1016/j.tetasy.2015.08.007
957-4166/Ó 2015 Elsevier Ltd. All rights reserved.
0

H. Temel et al. / Tetrahedron: Asymmetry 26 (2015) 1058–1064
1059
CHO
NH2
OH
D
OH
HC
N
Et
OH
OH
Et
(
S)-2-aminobutan-1-ol
2-hydroxy-1-naphthaldehyde
(S,Z)-1-((1-hydroxybutan-2-
ylimino)methyl)naphthalen-2-ol
Scheme 1. The synthesis of (S,Z)-1-((1-hydroxy butane-2-yl imino)methyl)naphthalene-2-ol, L.
hydrogen source offers an attractive route for reducing simple
valuable materials for asymmetric transfer hydrogenations. Fur-
thermore, to the best of our knowledge, there are not many reports
on asymmetric transfer hydrogenations of ketones using chiral
boron complexes as catalysts. These boron complexes were suc-
cessfully employed as ligands in boron-promoted asymmetric
transfer hydrogenations of various ketones.
unfunctionalized ketones to chiral alcohols.2
4–26
The reaction uses
inexpensive reagents and is usually easy to perform. Herein, the
chiral ligand was synthesized by the condensation of a chiral
amine and an aldehyde. The boronic acid derivatives were applied
obtain get boron complexes. Their structure identification was per-
1
13
formed by LC–MS, H NMR, C NMR, UV–Vis, FTIR, and elemental
analysis. Recently, we have reported on the synthesis and applica-
tions of a number of modified boron catalysts for transfer hydro-
2
2
. Results and discussion
2
1,26
genations.
In view of the promising results, boron complexes
.1. Spectroscopic identification
were shown to be efficient homogeneous hydrogenation catalysts
toward various substrates. By taking into account that these easily
prepared ligands were effective ligands in boron-catalyzed transfer
hydrogenations, we believed that boron catalysts would be
The synthetic strategy and reaction conditions adopted herein
are described in Scheme 1 for compound L. We first established
an easy methodology for the synthesis of (S)-2-aminobutan-1-ol
BLb
O
CH
N
B
O
OCH3
B(OH)2
H3CO
H
N
C
O
O
HO
OH
B
B
B(OH)2
B(OH)2
BLa
N CH
BLc
O
CH
OH
HO
N
B
B
O
O
O
H
C
HO
OH
N
B
NO2
CH3
BLd
HC
O
B
N
NO2
CH3
O
Scheme 2. Proposed reactions of boronic derivative compounds BLa, BLb, BLc, and BLd.

1
060
H. Temel et al. / Tetrahedron: Asymmetry 26 (2015) 1058–1064
25
and 2-hydroxy-1-naphthaldehyde based, in part, on conditions
rings.34–36 The specific rotations were determined as [
a
]
= +1.5
= ꢀ10.6 (c 1, DMSO),
= ꢀ6.7 (c 0.5, DMSO) for BLa, BLb, BLc, and BLd, respectively.
2
7
25
20
reported by Duan.
The chiral boron based compounds BL
(c 0.5, DMSO), [
[a]
D
a
]
D
= ꢀ3.5 (c 0.5, DMSO), [
a]
D
2
5
obtained from the interaction of (S)-2-aminobutan-1-ol and 2-hy-
droxy-1-naphthaldehyde have similar data to the previously men-
tioned spectroscopic result (Scheme 2). (R)-2-Aminobutan-1-ol
was also used for the targetted product, but unfortunately it did
not react.
2.2. SEM and EDX results of compounds
The surface structure morphology of BLa–d compounds was
determined under low vacuum at different magnifications by scan-
ning electron microscope (SEM). The energy-dispersive X-ray spec-
troscopy (EDX) analyses were also accomplished simultaneously to
investigate qualitative elemental percentages (Fig. 1).
The peaks between 8.08 and 8.64 ppm correspond to the
azomethine (CH@N) proton;2
8–30
the disappearance of the OH
groups indicates the binding of the boron atoms to the oxygen.
ꢀ
1
The stretching vibrations of B–O are seen from 1312 cm
1
to
ꢀ1
ꢀ1
378 cm ; the stretching of B–Ph at 751–852 cm shows the
interactions; the exact mass spectra of all compounds, which were
2.3. Thermal investigation
obtained with a positive charged scan, indicate the meaningful val-
ues as calculated and expected.3
1,29,32,33
The UV–Vis analysis of the
The thermal behavior of the compounds, which were used as
catalysts, was investigated by TGA/DTA under a nitrogen atmo-
sphere with heating at 10 °C per minute. The thermograms showed
⁄
⁄
boronic based molecules demonstrates the n?
tronic transitions arising from the donor atoms and aromatic
p and p?p elec-
Compound
SEM Images
EDX Data
BLa
BLb
BLc
BLd
Figure 1. SEM images and EDX results of BLa, BLb, BLc, BLd.

H. Temel et al. / Tetrahedron: Asymmetry 26 (2015) 1058–1064
1061
Figure 2. TGA and DTA thermograms of compounds.
the boron compounds to be relatively stable up to 300 °C, since
there was no remarkable weight loss until that temperature. Due
to boron’s nature, BL compounds had a resistance against decom-
position at lower temperatures. However, catalytic reactions need
stable reagents, which can prompt the hydrogenation throughout
the reactions (Fig. 2).
Single and double step decompositions were attained for BLa–d
compounds in the range of 25–800 °C. Weight losses were calcu-
lated as: 8.18% BLa; 80.85% and 5.19% BLb; 58.16% and 4.47%
BLc; 77.12% (only at one step) BLd. Maintaining thermally stable
without any weight loss indicates that they may be favorable for
higher temperature catalyst reactions.
acetophenone by iso-PrOH in the presence of KOH is summarized
in Table 1. Catalytic experiments were carried out under an argon
atmosphere using standard Schlenk-line techniques. These sys-
tems catalyzed the reduction of acetophenone into the correspond-
ing alcohol (S)- or (R)-1-phenylethanol in the presence of KOH as a
promoter. To an iso-PrOH solution of the boron-complex, an appro-
priate amount of acetophenone and KOH/iso-PrOH solutions were
added at room temperature. The solution was stirred for several
hours, and then examined with capillary GC analysis. At room tem-
perature, the transfer hydrogenation of acetophenone occurred
3
7
very slowly, with low conversion (up to 32%, 72 h) and low to
moderate enantioselectivity (up to 69% ee) (entries 1–4). Due to
the reversibility at room temperature, prolonging the reaction time
(144 h) led to a decrease in the enantioselectivity, as indicated by
2
.4. Asymmetric transfer hydrogenation of acetophenone
d
38,39
derivatives with iso-PrOH
the catalytic results collected with BLa–d (entries 1 and 2, ).
Furthermore, as can be inferred from Table 1 (entries 5–8) the
presence of a base is necessary to observe appreciable conversions.
The base facilitates the formation of the ruthenium alkoxide by
abstracting the proton of the alcohol and subsequently the alkox-
ide undergoes b-elimination to give ruthenium hydride, which is
Chiral complexes BLa–d have been investigated as catalyst
precursors for the asymmetric transfer hydrogenation of acetophe-
none under variable conditions. Additionally, a comparison of
complexes as precatalysts for the asymmetric hydrogenation of

1
062
H. Temel et al. / Tetrahedron: Asymmetry 26 (2015) 1058–1064
Table 1
Asymmetric transfer hydrogenations of acetophenone with iso-PrOH catalyzed by boron-complexes BLa–d
HO
O
H
Cat.
*
iso-PrOH
acetone
Entry
Complex
S/C/NaOH
Time
Conversion(%)[f]
% ee[g]
Configuration[h]
a
d
d
d
d
1
2
3
4
BLa
100:1:5
100:1:5
100:1:5
100:1:5
72 h (144 h)
72 h (144 h)
72 h
30 (46)
32 (47)
13
69 (63)
32 (30)
57
(S)
(S)
(S)
a
a
a
BLb
BLc
BLd
72 h
21
34
(S)
b
b
b
b
12 h
12 h
12 h
12 h
<3
<3
<3
<3
....
....
....
....
5
6
7
8
BLa
BLb
BLc
BLd
100:1
100:1
100:1
100:1
....
....
....
....
c
c
c
c
12 h (12 h)
12 h (12 h)
36 h
e
e
e
(S)
(S)
(S)
(S)
9
BLa
BLb
BLc
BLd
100:1:5
100:1:5
100:1:5
100:1:5
98 (97)
70 (71)
34 (33)
56
e
1
1
1
0
1
2
99 (98)
99
24 h
97
32
13
14
15
16
BLa
BLa
BLa
BLa
100:1:3
100:1:5
100:1:7
100:1:9
12 h
12 h
12 h
12 h
92
98
93
92
66
70
68
67
(S)
(S)
(S)
(S)
Reaction conditions.
a
At room temperature; acetophenone/Ru/NaOH, 100:1:5.
b
c
d
e
f
Refluxing in iso-PrOH; acetophenone/Ru, 100:1, in the absence of base.
Refluxing in iso-PrOH; acetophenone/Ru/NaOH, 100:1:5.
At room temperature; acetophenone/Ru/NaOH, 100:1:5, (64 h).
Refluxing in iso-PrOH; acetophenone/Ru/KOH, 100:1:5.
Determined by GC (three independent catalytic experiments).
g
Determined by capillary GC analysis using a chiral cyclodex B (Agilent) capillary column.
Determined by comparison of the retention times of the enantiomers on the GC traces with literature values, an (S)- or (R)-
h
configuration was obtained in all experiments.
an active species in this reaction. This is a mechanism that has
been proposed by several research groups on the studies of ruthe-
nium catalyzed transfer hydrogenation reaction by metal hydride
methoxy group, to the p-position decelerates the reaction, while
to the o-position increases the rate and improves the enantioselec-
tivity. The introduction of electron-withdrawing substituents, such
4
0–43
intermediates
namely, the role of the base is to generate a
2
as F or NO , to the para positions of the aryl ring of the ketone,
more nucleophilic alkoxide ion, which can rapidly attack the boron
complex responsible for the dehydrogenation of iso-PrOH. In addi-
tion, the choice of base, such as KOH and NaOH, had little influence
resulted in an improved activity with good enantioselectivity
(entries 1–4 and 13–16, Table 2). The introduction of electron with-
drawing substituents to the para position of the aryl ring of the
ketone decreased the electron density of the C@O bond so that the
activity was improved, thus giving rise to easier hydrogenation.4
e
on the conversion or enantioselectivity (entries 9 and 10, ). Opti-
4,45
mization studies of the catalytic reduction of acetophenone in
iso-PrOH showed that good activity was obtained with a base/
ligand ratio of 5:1 (Table 1). The reduction of acetophenone into
3. Experimental
(S)- or (R)-1-phenylethanol could be achieved in high yield by
increasing the temperature up to 82 °C (Table 1, entries 9–12).
Moreover, it is noteworthy that the catalytic system, BLa–d dis-
plays differences in reactivity. Compared to the other complexes,
BLa appeared to be more effective than the other catalysts.
Our study revealed that the activity and enantioselectivity of
the catalyst were sensitive to the substrate structures. Hence com-
plexes BLa–d were further investigated in transfer hydrogenations
of substituted acetophenone derivatives, and the results of these
transformations are presented in Table 2. The catalytic reduction
of acetophenone derivatives was all investigated with the condi-
tions optimized for acetophenone. The results in Table 2 demon-
3.1. Materials and methods
Analytical grade and deuterated solvents were purchased from
Merck. The starting materials phenyl boronic acid, 6-methoxy-
naphthalen-2-ylboronic acid, 4-methyl-3-nitrophenylboronic acid
and 1,4-phenylenediboronic acid were purchased from Fluka and
1
13
used as received. H NMR (at 400.1 MHz), and C NMR (at
100.6 MHz) spectra were recorded on a Bruker Avance 400 spec-
trometer, with TMS (tetramethylsilane) as an internal reference.
The IR spectra were recorded on a Mattson 1000 ATI UNICAM FT-
IR spectrometer as KBr pellets. Specific rotations were taken on a
Perkin–Elmer 341 model polarimeter. Elemental analysis was car-
ried out on a Fisons EA 1108 CHNS-O instrument. Melting points
were recorded by a Gallenkamp Model apparatus with open capil-
laries. GC analyses were performed on a Shimadzu GC 2010 Plus
Gas Chromatograph equipped with cyclodex B (Agilent) capillary
strate that
a range of acetophenone derivatives can be
hydrogenated with good enantioselectivities. Complex BLa showed
the highest activity with good enantioselectivity for most of the
ketones listed in Table 2. Furthermore, the position and electronic
properties of the ring substituents also influenced the hydrogena-
tion results. The highest enantioselectivity was found for the trans-
fer hydrogenation of o-methoxyacetophenone (78% ee), while the
lowest enantioselectivity was observed in the transfer hydrogena-
tion of p-methoxyacetophenone. From these results it can be seen
that the introduction of an electron-donating group, such as
column (30 m ꢁ0.32 mm I.D. ꢁ0.25
lm film thickness). Racemic
samples of alcohols were obtained by reduction of the correspond-
ing ketones with NaBH and used as the authentic samples for ee
4
determination. The GC parameters for asymmetric transfer hydro-
genation of ketones were as follows; initial temperature, 50 °C;

H. Temel et al. / Tetrahedron: Asymmetry 26 (2015) 1058–1064
1063
Table 2
Asymmetric transfer hydrogenation results for substituted acetophenones catalyzed by boron-complexes, (BLa–d)a
OH
O
OH
O
Cat / NaOH
R
+
R
+
Entry
Catalyst
Substrate
Product
OH
Time
Conversion(%)[b]
ee (%)[c]
Configration[d]
O
1
2
3
4
BLa
BLb
BLc
BLd
4 h
4 h
12 h
8 h
98
99
98
97
72
36
58
34
(S)
(S)
(S)
(S)
*
F
F
O
OH
*
5
6
7
8
BLa
BLb
BLc
BLd
7 h
98
97
98
99
73
35
59
35
(S)
(S)
(S)
(S)
7 h
16 h
12 h
Cl
Cl
O
O
OH
*
9
BLa
BLb
BLc
BLd
10 h
10 h
20 h
16 h
98
98
97
99
73
36
60
37
(S)
(S)
(S)
(S)
1
1
1
0
1
2
Br
Br
OH
*
13
14
15
16
BLa
BLb
4 h
4 h
12 h
8 h
98
99
99
98
71
35
58
36
(S)
(S)
(S)
(S)
BLc
BLd
O2N
O2N
OMe
O
OMe OH
*
17
18
19
20
BLa
BLb
BLc
BLd
15 h
15 h
40 h
30 h
97
99
98
99
78
42
69
47
(S)
(S)
(S)
(S)
O
OH
*
21
22
23
24
BLa
BLb
24 h
24 h
48 h
36 h
97
99
98
99
63
30
51
27
(S)
(S)
(S)
(S)
BLc
BLd
MeO
MeO
a
b
c
Catalyst (0.005 mmol), substrate (0.5 mmol), iso-PrOH (5 mL), NaOH (0.025 mmol %), 82 °C, the concentration of acetophenone is 0.1 M.
Purity of compounds is checked by NMR and GC (three independent catalytic experiments), yields are based on aryl ketone.
Determined by capillary GC analysis using a chiral cyclodex B (Agilent) capillary column (30 m ꢁ0.32 mm I.D. ꢁ0.25
lm film thickness).
d
Determined by comparison of the retention times of the enantiomers on the GC traces with literature values.
initial time 1.1 min; solvent delay, 4.48 min; temperature ramp
.3 °C/min; final temperature, 150 °C; initial time 2.2 min; temper-
ature ramp 2.15 °C/min; final temperature, 250 °C; initial time
.3 min; final time, 44.33 min; injector port temperature, 200 °C;
detector temperature, 200 °C, injection volume, 2.0 L.
3226
1641
m
(–OH), 3056
m
(Ph–CH), 2965
m
(Alif–CH), 1622
m
(C@N),
+
1
m(Ph–CH@CH–), 1183
m
(Ph–O). m/z: 244 [M+H ] C15H17NO
2
A
(M :243.30 g/mol).
3
l
3.4. General procedure for synthesis of BL
3
.2. General procedure for the transfer hydrogenation of
At first, 1 mmol of chiral ligand was dissolved in 15 mL ethanol
in a round bottom flask. Then an equivalent amount (1 mmol for
BLa, BLb, and BLd; 2 mmol for BLc) of the boronic derivative com-
pounds was added to the ligand solution. The reaction mixture was
conducted for 5 h at 110 °C. Yellow colored solid products were
precipitated. After filtering and washing with an excess of solvent,
they were dried in an oven.
ketones
Typical procedure for the catalytic hydrogen-transfer reaction:
a solution of boron-complexes (0.01 mmol), NaOH (0.05 mmol)
and the corresponding ketone (1 mmol) in degassed iso-PrOH
(
10 mL) was refluxed until the reaction was completed. Next, a
sample of the reaction mixture was taken, diluted with acetone
and analyzed immediately by GC; the conversions obtained are
related to the residual unreacted ketone.
3.4.1. Data for BLa, BLb, BLc, and BLd
1
BLa: H NMR (ppm, DMSO-d
6
): d = 0.92 (t, 3H, –CH
–), d = 3.27 (p, H, –CH–(CH ), d = 4.04 (dd, 2H, –CH
d = 7.2 (m, Ph–CH), d = 9.06 (–CH@N), d = 7.19, 7.32, 7.62, 7.64,
3
), d = 1.59 (p,
2
H, –CH
2
2
)
2
2
–O–),
3
.3. Synthesis of chiral ligand L
ꢀ
1
7
.78, 8.07 (m, naphthalene–CH). FTIR-ATR (cm ): 1377–1359
(B–O), 1058 and 1027 (B–C), 748 (B–Ph), 3061 (Ph–CH), 2931
–), 1608 (C@N), 1125 ((–CH )–CH–N@), 1625
(Ph–CH@CH–), 1150 (Ph–O). m/z: 330.16 [M+H ] C21
m
(
S,Z)-1-((1-Hydroxy butane-2-yl imino)methyl)naphthalene-2-
ol L was obtained by the reaction of (S)-2-aminobutan-1-ol and
-hydroxy-1-naphthaldehyde in ethanol. The reaction was left
m
m
m
m(–CH
2
–CH
2
–CH
2
m
m
2
+
2
m
m
H
20NO
2
3
B
2
7
for 6 h. The product had a higher viscose form and was quite
(M
A
:329.20 g/mol). UV–vis (nm):
k
(
1
= 257
(e
= 2.57 ꢁ10 ),
3
3
air sensitive. The (R)-enantiomer was synthesized as described in
k
2
= 262
(e
= 2.62 ꢁ10 ),
k
3
= 307
e
= 3.07 ꢁ10 ),
4
k = 401
2
7 1
3
the literature.
d = 1.66 (p, 2H, –CH
H, –CH –OH), d = 2.05 (s, 1H, CH
H NMR (ppm, DMSO-d
–), d = 3.20 (p, H, –CH–(CH
–OH), d = 5.10 (s, 1H, Ph–OH),
6
): d = 0.94 (t, 3H, –CH
3
),
(
e
= 4.01 ꢁ10 ) (solvent: THF/DMSO). Elemental Analysis: Found
2
2
)
2
), d = 3.95 (q,
(Calculated) C, 76.53 (76.62), H, 4.08 (4.12), N, 4.21 (4.25). Melting
2
2
2
point: 238–240 °C.
1
d = 8.16 (–CH@N), d = 7.20, 7.84, 7.61, 7.33, 7.53 (m,
BLb: H NMR (ppm, DMSO-d
6
): d = 1.15 (t, 3H, –CH
3
), d = 1.74
2
5
ꢀ1
naphthalene–CH). [
a]
D
= ꢀ11.9 (c 0.5, DMSO). FTIR-ATR (cm ):
(p, 2H, –CH
2
–), d = 3.30 (p, H, –CH–(CH ), d = 3.70 (s, naph-
2 2
)

1
064
H. Temel et al. / Tetrahedron: Asymmetry 26 (2015) 1058–1064
thalene–O–CH
3
), d = 4.20 (dd, 2H, –CH
2
–O–), d = 7.13, 7.20, 7.40 (m,
3. Kabalka, G. W. J. Organomet. Chem. 1986, 298, 1–35.
4.
5.
6.
Kabalka, G. W.; Guindi, L. H. M. J. Organomet. Chem. 1991, 404, 1–48.
Hall, D. G. In Boronic Acids; Hall, D. G., Ed.; Wiley-VCH: Weinheim, 2005.
Brown, H. C. In 25th International Congress of Pure and Applied Chemistry;
Marcus, Y., Ben-Dor, L., Eds.; Pergamon, 1977; pp 49–60.
–
B-naphthalene–CH), d = 9.09 (–CH@N), d = 7.28, 7.42, 7.64, 7.81
ꢀ
1
(
m, naphthalene–CH). FTIR-ATR (cm ): 1376–1345
and 1017 (B–C), 752 (B–Ph), 3052 (Ph–CH), 2961
–CH –), 1607 (C@N), 1127 ((–CH )–CH–N@), 1625
(Ph–CH@CH–), 1168 (Ph–O). m/z: 410 [M+H ] C26
= 304
m(B–O), 1059
m
m
m
7
.
.
Ferrier, R. J. In Advances in Carbohydrate Chemistry and Biochemistry; Tipson, R.
S., Derek, H., Eds.; Academic Press, 1978; pp 31–80.
Smoum, R.; Srebnik, M. In Studies in Inorganic Chemistry; Hijazi Abu Ali, V. M. D.,
Morris, S., Eds.; Elsevier, 2006; pp 391–494.
m(–CH
2
–CH
2
2
m
m
2
+
m
m
H
24NO
3
3
B
8
(
A
M :409.28 g/mol). UV–vis (nm):
k
1
(e
= 3.04 ꢁ10 ),
3
3
9. Springsteen, G.; Wang, B. Tetrahedron 2002, 58, 5291–5300.
k
2
= 330 (
e
= 3.30 ꢁ10 ), k
3
= 420 (
e
= 4.20 ꢁ10 ) (solvent: THF/
1
0. Peter Atkins, T. O.; Jonathan Rourke; Mark Weller; Fraser Armstrong; Micheal
Hagerman In Inorganic Chemistry; Peter Atkins, T. O., Jonathan Rourke, Mark
Weller, Fraser Armstrong, Micheal Hagerman, Eds.; W.H. Freeman and
Company: New York, 2009.
DMSO). Elemental Analysis: Found (Calculated) C, 76.17 (76.30),
H, 4.58 (4.61), N, 3.40 (3.42). Melting point: 242–245 °C.
1
BLc: H NMR (ppm, DMSO-d
6
): d = 9.07 (s, CH@N), d = 7.41, 7.45,
1
1
1. Kelly, A. M., University of Bath, 2008.
2. Özçelik, Sß .; Gül, A. J. Organomet. Chem. 2012, 699, 87–91.
7
(
3
1
.63, 7.65, 7.73 (naphthalene–CH) d = 7.35 (m, Ph-H), d = 4.28
dd, 2H, –CH –O–), d = 3.36 (m, 1H, @N–CH–(CH ), d = 0.89 (t,
), d = 1.58 (p, 2H, –CH–CH –CH ). FTIR-ATR (cm ):
(B–O), 1062 (B–C), 747 (B–Ph), 3055 (Ph–CH), 2967
–CH –CH –), 1613 (C@N), 1127 ((–CH )–CH–N@), 1630
(Ph–CH@CH–),1150 (Ph–O). m/z: 558 [M+H ] C36
557.29 g/mol). UV–vis(nm): = 397
= 3.97 ꢁ10 ),
2
2
)
2
13. Stacey, B. E.; Tierney, B. Carbohydr. Res. 1976, 49, 129–140.
ꢀ1
14. Yang, D.; Cong, R.; Gao, W.; Yang, T. J. Solid State Chem. 2013, 201, 29–34.
15. Lee, S. M.; Perng, T. P. Int. J. Hydrogen Energy 2000, 25, 831–836.
16. Kelly, G. S. Altern. Med. Rev. 1997, 2, 48–56.
H, –CH
342
3
2
3
m
m
m
m
m(–CH
2
2
2
m
m
2
+
17. Penland, J. G. Environ. Health Perspect. 1994, 102, 65–72.
18. Noyori, R. Asymmetric Catalysis in Organic Synthesis; Wiley, 1993.
19. Patti, A.; Nicolosi, G. Tetrahedron: Asymmetry 2000, 11, 3687–3692.
m
m
H
34
N
2
O
2
B
2
3
(
M
A
:
k
1
(e
20. Stinson, S. C. Chem. Eng. News Arch. 2001, 79, 45–57.
3
k
2
= 422 (
e
= 4.22 ꢁ10 ) (solvent: DMSO). Elemental Analysis:
2
1. Jacobsen, E. N.; Pfaltz, A.; Yamamoto, H. In Comprehensive Asymmetric Catalysis:
Supplement 1; Springer Science & Business Media, 2004; Vol. 1,
2. Noyori, R.; Ohkuma, T. Angew. Chem., Int. Ed. 2001, 40, 40–73.
3. Sheldon, R. A. Chirotechnology: Industrial Synthesis of Optically Active
Compounds; CRC Press, 1993.
Found (Calculated) C, 58.39 (58.51), H, 4.81 (4.90), N, 4.77 (4.83).
2
2
Melting point: 308–310 °C.
1
BLd: H NMR (ppm, DMSO-d
6
): d = 9.10 (s, –CH@N), d = 7.33,
7
.56, 7.54, 7.82, 7.98 (m, naphthalene–CH), d = 7.33, 6.85 (Ph–H),
d = 0.93 (t, 3H, –CH ), d = 1.04 (p, 2H, –CH–CH –CH ), d = 2.34 (s,
H, Ph–CH ), d = 3.25 (p, H, –CH–(CH ), d = 4.26 (dd, 2H, –CH
O–). FTIR-ATR (cm ): 1378–1334 (B–O), 1078–1013 (B–C),
((–CH )–CH–N@), 1609
(Ph–CH@CH–),1469 (Ph–CH
B (M
= 311 (
24. De Graauw, C.; Peters, J.; Van Bekkum, H.; Huskens, J. Synthesis 1994, 1007–
017.
1
3
2
3
25. Noyori, R.; Hashiguchi, S. Acc. Chem. Res. 1997, 30, 97–102.
3
3
2
)
m
m
2
2
–
26. Zassinovich, G.; Mestroni, G.; Gladiali, S. Chem. Rev. 1992, 92, 1051–1069.
ꢀ
1
m
27. Xie, L.-X.; Wei, M.-L.; Sun, Q.-Z.; Duan, C.-Y. Chin. J. Inorg. Chem. 2007, 23, 484–
88.
8. Barba, V.; Vázquez, J.; López, F.; Santillan, R.; Farfán, N. J. Organomet. Chem.
005, 690, 2351–2357.
4
7
48
C@N), 1127
195
UV–vis(nm): k
= 328 (
= 3.28 ꢁ10 ), k
Elemental Analysis: Found (Calculated) C, 68.38 (68.06), H, 4.41
4.45), N, 7.18 (7.22). Melting point: 227–229 °C.
m
(B–Ph), 3069
m
(Ph–CH), 2970
2
m
2
(
1
m
(Alif–C–N@), 1626
(Ph–O). m/z: 389 [M+H ] C22
m
m
3
),
2
+
m
H
21
N
2
O
4
A
:388.22 g/mol).
= 3.11 ꢁ10 ),
29. Erno Pretsch, P. B. u.; Badertscher, Martin Structure Determination of Organic
Compounds, 4th ed.; Springer: Berlin Heidelberg, 2008.
30. Vyas, K. M.; Jadeja, R. N.; Gupta, V. K.; Surati, K. R. J. Mol. Struct. 2011, 990, 110–
3
3
1
= 281 (
e
= 2.81 ꢁ10 ), k
2
e
3
3
k
3
e
4
= 380 (
e
= 3.80 ꢁ10 ). (Solvent: THF).
120.
31. Abderrazek Oueslati, S. K.; Faouzi, Hlel; Mohamed, Gargouri; Alain, Fort Phys.
Sci. 2011, 1.
(
32. Faniran, J. A.; Shurvell, H. F. Can. J. Chem. 1968, 46, 2089–2095.
33. Singaram, B.; Cole, T. E.; Brown, H. C. Organometallics 1984, 3, 774–777.
34. Kilic, A.; Aydemir, M.; Durgun, M.; Meriç, N.; Ocak, Y. S.; Keles, A.; Temel, H. J.
Fluorine Chem. 2014, 162, 9–16.
Acknowledgements
3
3
3
5. Nagata, Y.; Chujo, Y. Macromolecules 2008, 41, 3488–3492.
6. Tokoro, Y.; Nagai, A.; Chujo, Y. Macromolecules 2010, 43, 6229–6233.
7. Takehara, J.; Hashiguchi, S.; Fujii, A.; Inoue, S.-I.; Ikariya, T.; Noyori, R. Chem.
Commun. 1996, 233–234.
Partial support of this study by Dicle University Research Fund
DUBAP, Project numbers: 14-FF-78 and 14-EZF-14) and The Scien-
tific and Technological Research Council of Turkey (TUBITAK) are
gratefully acknowledged. We would like also thank to Dicle
University Science and Technology Research Center (DUBTAM)
for its kind contribution by offering analysis.
(
3
3
8. Hashiguchi, S.; Fujii, A.; Haack, K. J.; Matsumura, K.; Ikariya, T.; Noyori, R.
Angew. Chem., Int. Ed. 1997, 36, 288–290.
9. Ikariya, T.; Blacker, A. J. Acc. Chem. Res. 2007, 40, 1300–1308.
40. Chen, J.-S.; Li, Y.-Y.; Dong, Z.-R.; Li, B.-Z.; Gao, J.-X. Tetrahedron Lett. 2004, 45,
415–8418.
8
4
1. Doucet, H.; Ohkuma, T.; Murata, K.; Yokozawa, T.; Kozawa, M.; Katayama, E.;
England, A. F.; Ikariya, T.; Noyori, R. Angew. Chem., Int. Ed. 1998, 37, 1703–1707.
2. Hannedouche, J.; Clarkson, G. J.; Wills, M. J. Am. Chem. Soc. 2004, 126, 986–987.
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