Synthesis and structure of an air-stable bis(pentamethylcyclopentadienyl) zirconium pentafluorbezenesulfonate and its application in catalytic epoxide ring-opening reactions

Article abstract of DOI:10.1016/j.tet.2018.01.016

An air-stable mononuclear complex of bis(pentamethylcyclopentadienyl) zirconium pentafluorbezenesulfonate was successfully synthesized by treating C₆F₅SO₃Ag with [(CH₃)₅Cp]₂ZrCl₂, which showed the cationic uninuclear structure of [{(CH₃)₅Cp}₂Zr(CH₃CN)₂(H₂O)][OSO₂C₆F₅]₂·CH₃CN (1) confirmed by the X-ray analysis. Complex 1 was also characterized by other techniques and found to have the good nature of air-stability, water tolerance, thermally-stability and strong Lewis-acidity. Moreover, the complex showed high catalytic activity and recyclability in catalytic epoxide ring-opening reactions by amines or alcohols. This catalytic system affords a simple and efficient approach for synthesis of β-amino alcohols or β-alkoxy alcohols.

Full text of DOI:10.1016/j.tet.2018.01.016

Accepted Manuscript
Synthesis and structure of an air-stable bis(pentamethylcyclopentadienyl) zirconium
pentafluorbezenesulfonate and its application in catalytic epoxide ring-opening
reactions
Ningbo Li, Lingxiao Wang, Haojiang Wang, Jie Qiao, Wenjie Zhao, Xinhua Xu, Zhiwu
Liang
PII:
S0040-4020(18)30038-3
10.1016/j.tet.2018.01.016
TET 29231
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 6 December 2017
Revised Date: 8 January 2018
Accepted Date: 9 January 2018
Please cite this article as: Li N, Wang L, Wang H, Qiao J, Zhao W, Xu X, Liang Z, Synthesis and
structure of an air-stable bis(pentamethylcyclopentadienyl) zirconium pentafluorbezenesulfonate
and its application in catalytic epoxide ring-opening reactions, Tetrahedron (2018), doi: 10.1016/
j.tet.2018.01.016.
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Synthesis and structure of an air-stable
bis(pentamethylcyclopentadienyl) zirconium
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pentafluorbezenesulfonate and its application in catalytic epoxide ring-opening reactions
Ningbo Li,a,* Lingxiao Wang,a Haojiang Wang, a Jie Qiao,a Wenjie Zhao,a,* Xinhua Xu,b,* and Zhiwu Liangb
a Basic Medical College, Shanxi Medical University, Taiyuan 030001, China;
b College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
Fax: (+86) 351-4135645; E-mail: ningboli@sxmu.edu.cn; zhaowenjie@hnu.edu.cn; xhx1581@hnu.edu.cn

1
ACCEPTED MANUSCRIPT
Tetrahedron
journal homepage: www.elsevier.com
Synthesis and structure of an air-stable bis(pentamethylcyclopentadienyl) zirconium
pentafluorbezenesulfonate and its application in catalytic epoxide ring-opening reactions
Ningbo Li,a,* Lingxiao Wang,a Haojiang Wang,a Jie Qiao,a Wenjie Zhao,a,* Xinhua Xu,b,* and Zhiwu Liangb
a Basic Medical College, Shanxi Medical University, Taiyuan 030001, China;
b College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
Fax: (+86) 351-4135645; E-mail: ningboli@sxmu.edu.cn; zhaowenjie@hnu.edu.cn; xhx1581@hnu.edu.cn
ARTICLE INFO
ABSTRACT
Article history:
Received
An air-stable mononuclear complex of bis(pentamethylcyclopentadienyl) zirconium
pentafluorbezenesulfonate was successfully synthesized by treating C6F5SO3Ag with
Received in revised form
Accepted
[(CH3)5Cp]2ZrCl2,
[{(CH3)5Cp}2Zr(CH3CN)2(H2O)][OSO2C6F5]2
which
showed
the
cationic
uninuclear
structure
of
·CH3CN (1) confirmed by the X-ray analysis.
Available online
Complex 1 was also characterized by other techniques and found to have the good nature of air-
stability, water tolerance, thermally-stability and strong Lewis-acidity. Moreover, the complex
showed high catalytic activity and recyclability in catalytic epoxide ring-opening reactions by
amines or alcohols. This catalytic system affords a simple and efficient approach for synthesis
of β-amino alcohols or β-alkoxy alcohols.
Keywords:
Zirconium pentafluorbezenesulfonate
Lewis acid
Epoxide
Ring-opening reaction
2009 Elsevier Ltd. All rights reserved
.
1. Introduction
It is well known that zirconocene compounds have
attracted much attention due to their broad application in
organic synthesis.13 However, their potential as Lewis acid
catalysts have rarely been reported, which may be resulted
from the lower Lewis acidity of Cp2ZrCl2 and their
derivatives.14 In 2006, Otera group found that the
perfluoroctanesulfonate groups could be used as effective
counter anions to increase the acidity as well as the water-
tolerant ability.15 With this in mind, we have synthesized a
Lewis acid promoted ring opening of epoxides with amines
or alcohols is important organic transformation for production
of β-amino alcohols or β-alkoxy alcohols, which are versatile
intermediates in synthesizing a vast range of biologically
active products, unnatural amino acids and chiral auxiliaries.1
And ring-opening reaction of epoxides have been applied in
the manufacture of drugs and pharmaceuticals,2 such as (-)-
swainsonine, HBV inhibitor and lasalocid (Fig. 1).
series
of
air-stable
zirconocene
perfluoroalkyl(aryl)sulfonates complexes, which showed
strong Lewis acidity and high catalytic activity in many
organic reactions 16
. It should be noted that the remarkable
air-stability and strong Lewis acidity of these complexes
mainly hinges on the perfluoroalkyl(aryl)sulfonate groups.
However, their relatively low solubility in organic solvents
Fig. 1. Ring opening of epoxide applied in pharmaceuticals
owing
to
the
strong
lipophobic
nature
of
The classical protocol for synthesis of β-amino alcohols is
direct aminolysis of epoxides at elevated temperatures in an
excess amount of amines.3 Due to poor nucleophilicity of
alcohols, alcoholysis of epoxides requires either strongly
acidic or basic conditions.4 To avoid drawbacks of classical
aminolysis protocol and harsh conditions of alcoholysis, the
various methods have been developed to open epoxide ring
with amines or alcohols in the presence of Lewis acids
catalysts such as InCl3,5 ZrCl4,6 SbCl3,7 ZnCl2,8 BF3·OEt2,9
Cp2ZrCl2,10 Al(OTf)3,11 Cu(BF4)2.12 Nonetheless, there are
disadvantages with those methods, e.g. using air-sensitive
catalysts, elevated temperature, long reaction time, moderate
yields, poor regioselectivity, high catalyst loadings and poor
recyclability of catalysts. Thus, there is ongoing activity
aimed to establish a more simple and efficient catalytic
protocol to accomplish this transformation.
perfluorooctanesulfonate group possibly declined the
catalytic efficiency. To address this problem, we found that
alkyl group incorporated with Cp ring can increase the
solubility, as well as the catalytic efficiency.17 Also the
lipophobicity of perfluorobenzenesulfonate group was
weaker than that of the perfluorooctanesulfonate group, and
the toxicity of was lower than that of PFOS.18 Herein, we
successfully
bis(pentamethylcyclopentadienyl)
pentafluorbezenesulfonate
synthesized
and
characterized
zirconium
[{(CH3)5Cp}2Zr(CH3CN)2(H2O)][OSO2C6F5]2·CH3CN
Moreover, we reported its catalytic application in epoxide
ring-opening reactions by amines or alcohols in detail.
(1).
2. Results and discussion

2
ACCEPTED MANUSCRIPT
Complex 1 was synthesized by treatment of [(CH3)5Cp]2ZrCl2
with AgOSO2C6F5 (2 equiv) in CH3CN solution, and the yield
The thermal behavior of complex 1 was investigated by TG-
DSC under N2 atmosphere (Fig. 3). The TG-DSC curves
indicated three stages of weight loss. The endothermic step
below 100 °C can be attributed to the removal of water and
was 72% (Scheme 1)
.
o
CH3CN molecules. Complex 1 was stable up to about 260 C.
o
The weight loss of an exothermic nature at 300 C is plausibly
due to the oxidation of organic entities.
Conductivity measurement was applied to investigate its ionic
dissociation behavior in CH3CN (1.0 mmol·L-1). The molar
conductivity (Λ) of complex 1 thus measured at 20 °C was 137
ꢀS·cm-1 (see Table S1 in ESI). The large molar conductivity
value is consistent with the complete ionization into a 1:2
electrolyte,20 implying that the complex is cationic in the solid as
well as in the solution state. Another notable feature is the
unusual solubility of 1 in Acetone, CH3CN, THF, EtOAc and
MeOH (Table 1). Actually, owing to the existence of ten methyl,
one can see that complex 1 shows higher solubility in common
polar organic solvents than the complex [{CpZr(OH2)3}2(ꢀ2-
OH)2][SO3C6F5]4·6H2O.16b
Scheme 1. The synthetic route of complex 1
The crystal structure of 1 in the solid state was confirmed by
X-ray analysis. An ORTEP representation of 1 and selected
bonds and angles were shown in Fig. 2. The crystal structure of
complex 1 shows it is uninuclear, which is different from the
complex
[{CpZr(OH2)3}2(ꢀ2-OH)2][SO3C6F5]4·6H2O,
even
though their synthetic procedures are identical.16b In the crystal
structure of 1, the zirconium atom is stabilized by one water and
two CH3CN molecules, which also lie on the plane that bisects
the angle between the Cp ring planes. The Zr-O and Zr-N
Table 1 The solubility of complex 1 in organic solvents at 25 oC
Solubility (g/L) of 1 a
distances of
1 are 2.242(5), 2.303(6) and 2.297(6) Å,
Solvent
Acetone
CH3CN
THF
EtOAc
MeOH
Et2O
-
respectively. The C6F5SO3 ions and the dissociated CH3CN
molecule are packed around the complex cation and the C6F5
sides of the anion are clustered together to produce hydrophobic
domains.
647
842
346
128
384
16
CH2Cl2
n-Hexane
Toluene
0
0
0
a The sample was freshly prepared and recrystallized in vacuum
at toom temperature in a period of 2 hours.
In addition, we estimated the Lewis acidity of complex 1 by
the red shift (λem) of Lewis acid metal ions (Zr2+) with 10-
methylacridone on the basis of fluorescence spectra.21 The
fluorescence maxima (λem) of complex 1 is 471 nm (see Fig. S1
in ESI). We also employed the Hammett indicator method to
determine its acidity,22 and found that it showed a relatively
strong acidity with the acid strength of 0.8 < H0 < 3.3 (H0 being
the Hammett acidity function; see Fig. S2 in ESI). These features
facilitate its catalytic performance in catalytic epoxide ring-
opening reactions.
In view of the strongly acidic character of complex 1, 1.0
mol % complex 1 was assessed as a catalyst for the ring opening
reaction of epoxides with amines at room temperature under
solvent-free conditions. As shown in Table 2, complex 1 shows
high catalytic activity in the reaction of cyclohexene oxide with
different aromatic amines, the yield of the product is excellent,
i.e. from 91% to 99%. In all cases (4a-4j), only the major trans-
β-amino-alcohol isomers can be isolated, illustrating the high
diastereoselectivity of complex 1. The aromatic amines with
electron-donating groups (e.g., methyl and methoxyl, 4b-4e)
exhibit higher reaction activity than that with electron-
withdrawing groups (e.g., F, Cl, OCF3 and NO2, 4f-4i).
Gratifyingly, 1-naphthylamine also shows high reaction activity
with 95% yield (4j). Furthermore, high regio-selectivity is
observed when styrene oxide is adopted. As expected in the case
of styrene oxide α-amino was obtained as the major product (α/β
= 95/5) due to the formation of the stabilized benzylic cation
during the reaction (4k, 90%). The substituents in the phenyl
group of phenyl amine show only slight effect on the activity (4l,
4m, 92%, 88%). Different epoxides (e.g., epichlorohydrin,
epoxypropane) also exhibit high reactivity and regioselectivity
Fig. 2. The crystal structure of the complex 1 and selected bonds
(A˚) and angles (deg): The Zr1-O7, 2.242(5); Zr1-N1, 2.303(6);
Zr1-N2, 2.297(6); Zr1-C18, 2.570(7); Zr1-C19, 2.552(7); Zr1-
C20, 2.546(6); Zr1-C21, 2.526(7); Zr1-C22, 2.515(7); O7-Zr-N1
70.87(18); O7-Zr-N2 71.30(18); N2-Zr-N1 142.2(2); O7-Zr-C21
90.21(19).
It is notable that the solid samples remained as dry crystals or
powder after being kept in open air over three months. From the
viewpoint of operation, such an excellent air-stable complex
have great advantage over zirconocene bis(triflate) and the
traditional Lewis-acid catalysts.19
Fig. 3. TG-DSC curves of complex 1.

3
ACCEPTED MANUSCRIPT
(4n-4r, 84-93%), and β-aminoclcohols were obtained as the
major product due to the predominant attack of amine on the less
hindered carbon of the epoxide. In the cases of secondary amine
such as piperidine, morpholine, satisfactory yields can be
achieved (4s, 4t, 80%, 85%). Thus, an efficient protocol for the
aminolysis of epoxides has been developed.
(6e-6g, 87-96%), which owing to opening of styrene epoxide at
the benzylic position is favored due to the stable carbo-cation
generated.
Table 3 Product yields of alcoholysis reaction of epoxides with
alcohols catalyzed by 1 a
Table 2 Product yields of aminolysis reaction of epoxides with
amines catalyzed by 1 a
OH R3
O
1 (1.0 mol%)
R3R4NH
N
+
R1
R4
R1
R2
solvent-free, RT
R2
4
2
3
OH
OH
OH
CH3
N
H
N
H
N
H
CH3
4c, 96%
4a, 99%
4b, 99%
OCH3
OH
OCH3
OH
OH
Cl
N
H
N
H
N
H
OCH3
4d, 97%
4e, 98%
4f, 95%
OH
OH
OCF3
OH
a 1, 0.02 mmol; epoxides 2, 1.0 mmol; alcohols 5, 1.0 mmol;
solvent-free; Temp: RT; 6a, 6b, 6e, 6f: 1 h; 6c, 6g: 3 h; 6d: 8 h;
isolated yields.
N
H
N
H
N
H
NO2
F
4h, 92%
4g, 92%
4i, 91%
OH
OH
OH
H
In addition, the activities of complex 1 and different
zirconium compounds such as ZrCl4, (Me5Cp)2ZrCl2, ZrO(OTf)2,
ZrO(NO3)2·nH2O, [{CpZr(H2O)3}2(ꢀ2OH)2][OSO2C6F5]2·6H2O
were estimated by the reaction of cyclohexyl epoxide with
phenylamine or methyl alcohol (Table 4). As expected, no
product was obtained without a catalyst being present (Entry 1).
High yields were attained over complex 1 and zirconocene
pentafluorbezenesulfonate (Entry 2, 7). While the other catalysts
showed much lower yields, plausibly due to their moisture-
sensitive properties or lower Lewis acidity or weak lipophilicity
(Entry 3-6). However, It is noteworthy that the relatively lower
H
N
N
N
H
Ph
Ph
4k, 90%
H3C
4j, 95%
4l, 92%
OH
OH
OH
H
N
H
N
H
N
Cl
Cl
Ph
Cl
Cl
Cl
4o, 86%
4m, 88%
4n, 93%
OH
CH3
OH
H
N
OH
CH3
H
N
H
N
Cl
catalytic
efficiency
of
O2N
[{CpZr(H2O)3}2(ꢀ2OH)2][OSO2C6F5]2·6H2O may be owing to
the low solubility and lipophilic property, which makes the
substrates hard to approach the center metal atom for activating.
Thus, the results illustrate the superiority of complex 1 in the
ring opening reaction of epoxides.
4r, 90%
4p, 84%
4q, 99%
OH
OH
N
N
O
4s, 78%
4t, 80%
a
Table 4 Catalyst comparison in the ring opening reaction of
cyclohexyl epoxide with phenylamine or methyl alcohol
1, 0.01 mmol; epoxides 2, 1.0 mmol; amines 3, 1.0 mmol;
solvent-free; Temp: RT; 4a-4e, 4k-4l, 4q: 10 min; 4f-4g, 4j,
4m, 4o, 4r: 15 min, 4h-4i, 4p: 25 min; 4s-4t: 120 min;
isolated yields.
OH
PhNH2 (3a)
Ph
1 mol%,10 min
N
H
Cat.
(4a)
(6a)
To further explore the applicability of complex 1, we assessed
its catalytic activity towards the alcoholysis of epoxides with
various primary, secondary, and tertiary alcohols. As illustrated
in Table 3, in the presence of 2.0 mol% of complex 1, both
cyclohexyl epoxide and styrene epoxide show high reaction
activity and regio-selectivity with different alcohols at room
temperature under solvent-free conditions. First, we carried out
the ring opening reactions on cyclohexyl epoxide with primary
secondary, and tertiary alcohols, the reaction resulted in the
exclusive formation of the trans-products in very good to
excellent yields (6a-6d, 82-97%). Due to steric effect, isopropyl
alcohol and tertiary butanol took a slightly longer time than
primary alcohols but the regio-selectivity was not affected.
Further, we investigated styrene epoxide incorporating more
hindered hydroxyl functionality and the results showed high
yields of β-alkoxy alcohol as the major product were obtained
O
Solvent-free
RT
CH3OH (5a)
OH
2a
2 mol%, 1 h
CH3
O
Entry
Catalyste
No catalyst
Catalyst 1
ZrCl4
(Me5Cp)2ZrCl2
ZrO(OTf)2
4aa
0
99
68
32
63
51
6ab
0
97
58
42
60
57
87
1
2
3
4
5
6
ZrO(NO3)2•nH2O
7
[{CpZr(OH2)3}2(ꢀ2OH)2][SO3C6F5]4·6H2O 90
a
Cat., 0.01 mmol; 2a (1 mmol); 3a (1 mmol); RT; 10 min;
b
isolated yields. Cat., 0.02 mmol; 2a (1 mmol); 5a (1 mmol);
RT; 1h; isolated yields.

4
ACCEPTED MANUSCRIPT
To test the reusability of the catalyst and reproducibility of
catalytic performance, the complex 1 was subject to cycles of the
aminolysis reaction (2a + 3a → 4a) and the alcoholysis reaction
(2a + 5a → 6a). In the five trials of the above model reaction
catalyzed by complex 1, the yield slightly declines,
demonstrating the good recyclability of catalyst 1 (Table 5).
(s, 1F; ArF), -163.15 to -163.32 (m, 2F; ArF); IR(KBr): ν =
3378, 3228, 2909, 1643, 1531, 1503, 1381, 1230, 1110, 1044,
988, 936, 631, 537 cm-1; Anal. Calc’d for C38H41F10N3O7S2Zr: C,
45.77; H, 4.14; found: C, 45.71; H, 4.19.
Crystal data for 1: C38H41F10N3O7S2Zr; Mr = 997.08, Monoclinic,
space group P 21/n, a = 11.6502(6) Å, b = 29.4744 (14) Å, c =
3
12.8100 (7) Å; V = 4171.2(4) Å ; T = 293(2) K; Z = 4;
Table 5 Yields of the aminolysis reaction (2a + 3a → 4a) and
the alcoholysis reaction (2a + 5a → 6a) catalyzed by recovered
catalyst 1.a
Reflections collected/unique, 82001/7346, Rint = 0.1120, R1 =
0.0815, wR2 = 0.2456. GOF = 1.059; CCDC No. 1565685.
4.1.2 Typical procedure for solubility of complex 1: Acetone
(0.5 mL) was placed in a test tube; the complex 1 was added
gradually at room temperature. When the amount of added 1
exceeds 323.5 mg, insoluble 1 appeared. Based on this data,
solubility of 1 was determined to be 647 g·L-1.
Yield
Yield
Cat
Cat
Cycle
(%)b
(%)b
(%)c
(%)c
2a + 3a → 4a
2a + 5a → 6a
1
2
3
4
5
99
98
99
99
98
98
97
98
98
96
97
96
97
96
97
95
96
97
95
95
4.1.3 General procedure for the aminolysis and alcoholysis of
epoxides: A mixture of cyclohexyl epoxide (98 mg, 1.0 mmol)
and aniline (methyl alcohol) (93 mg, 1.0 mmol) and catalyst 1
(46 mg, 1.0 mol %) was stirred at room temperature for the
appropriate reaction time and monitored by TLC. Then the
mixture was diluted with CH2Cl2 (10 mL × 3). By means of
filtration, the catalyst was separated and used for the next cycle,
To the filtrate, after evaporation of the solvent, an oil mixture
was obtained. The residue was purified by a short column
chromatography eluted with ethyl acetate/petroleum ether
(80/20).
a
1, 0.01 mmol or 0.02 mmol; 2a: 1.0 mmol; 3a: 1.0 mmol; 5a:
1.0 mmol; Isolated yield of desired product. Isolated yield of
recovered catalyst.
b
c
3. Conclusions
In summary, we have synthesized and characterized
mononuclear
bis(pentamethylcyclopentadienyl)
zirconium
pentafluorbezenesulfonate. This complex is air-stable and
strongly acidic, and shows high catalytic efficiency and
regioselectivity in the aminolysis and alcoholysis of epoxides.
Moreover, the complex possesses good reusability. On account
of its stability, storability, as well as catalytic efficiency, the
complex should find a broad range of utility.
4.2. Characterization data
1
4.2.1 4a-4t are known compounds, and H NMR, 13C NMR and
Ms spectral data are summarized as follows:
o
1
2-Anilino-1-cyclohexanol (4a):6 white solid, M.p.: 58-59 C; H
NMR (400 MHz, CDCl3): δ ppm 7.21-7.17 (m, 2H), 6.77-6.71
(m, 3H), 3.38-3.32 (m, 1H), 3.17-3.12 (m, 1H), 2.84 (br.s, 1H),
2.14-2.11 (m, 2H), 1.80-1.69 (m, 2H), 1.41-1.28 (m, 3H), 1.10-
0.99 (m, 1H); 13C NMR (100 MHz, CDCl3) δ ppm 146.65,
129.36, 123.08, 115.64, 74.77, 60.59, 33.44, 31.75, 25.16, 24.45;
Ms (EI) m/z = 191.1 [M]+.
4. Experimental Section
4.1 General
All chemicals were purchased from Aldrich. Co. Ltd and used
as received unless otherwise indicated. The NMR spectra were
recorded at 25 ℃ on INOVA-400M (USA) calibrated with
tetramethylsilane (TMS) as an internal reference. Elemental
analyses were performed by VARIO EL III. TG-DSC analysis
was performed on a HCT-1 (HENVEN, Beijing, China)
instrument. IR spectra were recorded on NICOLET 6700 FTR
spectrophotometer (Thermo Electron Corporation). Conductivity
was measured on REX conductivity meter DDS-307. X-ray
single crystal diffraction analysis was performed with SMART-
APEX and RASA-7A by Shanghai Institute Organic Chemistry,
China Academy of Science. Fluorescence spectroscopy
(HITACHI F-4600) was measured in State Key Laboratory of
Chemo/Biosensing and Chemometrics, College of Chemistry
and Chemical Engineering, Hunan University (China). The
acidity was measured by Hammett indicator method as described
previously.18a Acid strength was expressed in terms of Hammett
acidity function (Ho) as scaled by pKa value of the indicators.
1
2-(4-Methylphenylamino)cyclohexanol (4b):6 Colorless oil; H
NMR (400 MHz, CDCl3): δ ppm 6.99 (d, J = 8.0Hz, 2H), 6.64
(d, J = 8.0 Hz, 2H), 4.78 (s, 1H), 3.36-3.30 (m, 1H), 3.11-3.05
(m, 1H), 2.57 (br.s, 1H), 2.24 (s, 3H), 2.12-2.09 (m, 2H), 1.78-
1.69 (m, 2H), 1.40-1.26 (m, 3H), 1.07-0.97 (m, 1H); 13C NMR
(100 MHz, CDCl3) δ ppm 145.58, 130.03, 128.07, 115.04, 74.74,
60.96, 33.31, 31.79, 25.30, 24.50, 20.58; Ms (EI) m/z = 205.1
[M]+.
1
2-(2-Methylphenylamino)cyclohexanol (4c):6 Colorless oil; H
NMR (400 MHz, CDCl3): δ ppm 7.26-7.06 (m, 2H), 6.80-6.68
(m, 2H), 3.46-3.40 (m, 1H), 3.24-3.18 (m, 1H), 2.74 (br.s, 1H),
2.16 (s, 3H), 2.13 (s, 2H), 1.79-1.72 (m, 2H), 1.45-1.29 (m, 3H),
1.09-1.02 (m, 1H); 13C NMR (100 MHz, CDCl3) δ ppm 145.90,
130.66, 127.39, 123.35, 118.14, 111.85, 74.96, 60.12, 33.43,
32.09, 25.27, 24.51, 17.90; Ms (EI) m/z = 205.1 [M]+.
4.1.1 Preparation of complex 1:
2-(4-Methoxyphenylamino)cyclohexanol (4d):23a White solid,
o
1
To a solution of [(CH3)5Cp]2ZrCl2 (0.432 g, 1.0 mmol) in 10 mL
CH3CN, a solution of AgOSO2C6F5 (0.724g, 2 mmol) in 5 mL
CH3CN was added. After the mixture was stirred in the absence
of light at room temperature for 2 hours, it was filtrated and
evaporated in the vacuum and the surplus concentrates were
maintained in the refrigerator for 24 hours, and the colorless
M.p.: 58-59 C; H NMR (400 MHz, CDCl3): δ ppm 6.79-6.73
(m, 2H), 6.70-6.64 (m, 2H), 3.75 (s, 3H), 3.34-3.29 (m, 1H),
3.02-2.97 (m, 1H), 2.53 (br.s, 1H), 2.15-2.08 (m, 2H), 1.76-1.69
(m, 2H), 1.39-1.26 (m, 3H), 1.07-0.98 (m, 1H); 13C NMR (100
MHz, CDCl3) δ ppm 153.26, 141.69, 116.71, 115.11, 74.64,
62.02, 55.98, 33.32, 31.74, 25.32, 24.51; Ms (EI) m/z = 221.1
[M]+.
1
crystals were obtained (0.718 g, 72%). Mp: 251-253 °C, H
NMR (400MHz, [d6] acetone) δ: 2.97 (s, 12H, CH3), 2.72 (s, 6H,
CH3), 2.52 (s, 12H, CH3), 2.13 (s, nH, CH3CN). 19F NMR
(376M, [d6] acetone): δ: -138.84 to -138.95 (m, 2F; ArF), 153.80
2-(4-(2,5-Dimethoxy)phenylamino)cyclohexanol
(4e):23c
Colorless oil; H NMR (400 MHz, CDCl3): δ ppm 6.69 (d, J =
1

5
ACCEPTED MANUSCRIPT
8.8Hz, 1H), 6.39 (d, J = 2.8Hz, 1H), 6.22-6.19 (m, 1H), 3.81 (s,
3H), 3.76 (s, 3H), 3.46-3.40 (m,1H), 3.15-3.09 (m,1H), 2.74
(br.s, 1H), 2.15-2.09 (m, 2H), 1.78-1.72 (m, 2H), 1.43-1.26 (m,
4H), 1.13-1.04 (m, 1H); 13C NMR (100MHz, CDCl3) δ ppm
154.95, 142.40, 138.90, 110.55, 100.02, 99.71, 74.73, 59.85,
56.27, 55.81, 33.37, 31.73, 25.29, 24.51; Ms (EI) m/z = 251.1
[M]+.
147.79, 139.66, 128.97, 128.90, 127.76, 126.74, 126.69, 122.49,
114.96, 67.27, 60.02; Ms (EI) m/z = 247.1 [M]+.
1
3-Chloro-2-phenylaminopropanol(4n):6 Colorless oil; H NMR
(400 MHz, CDCl3): δ ppm 7.23-7.19 (m, 2H), 6.76 (t, J = 7.6 Hz,
1H), 6.67 (d, J = 8.0 Hz, 2H), 4.09-4.04 (m, 2H), 3.39-3.34 (m,
1H), 3.24-3.19 (m, 2H); Ms (EI) m/z = 185.1 [M]+.
1
3-Chloro-2-(4-choloroanilino)propanol(4o):23a Colorless oil; H
2-(4-Chlorophenylamino)cyclohexanol(4f):6 White solid, M.p.:
NMR (400 MHz, CDCl3): δ ppm 7.13 (d, J = 9.2 Hz, 2H), 6.57
(d, J = 8.4 Hz, 2H), 4.19-4.03 (m, 1H), 3.65-3.59 (m, 2H), 3.36-
3.32 (m, 1H), 3.21-3.17 (m, 2H); Ms (EI) m/z = 219.1 [M]+.
3-Chloro-2-(3-nitroanilino)propanol(4p):23a Yellow oil; 1H
NMR (400 MHz, CDCl3): δ ppm 7.55-7.54 (m, 1H), 7.44-7.43
(m, 1H), 7.31-7.26 (m, 1H), 6.94-6.91 (m, 1H), 4.42 (s, 1H),
4.15-4.10 (m, 1H), 3.74-3.64 (m, 2H), 3.46-3.42 (m, 1H), 3.31-
3.26 (m, 1H), 2.51 (d, J = 5.2 Hz, 1H); Ms (EI) m/z = 230.1 [M]+.
o
1
99-102 C; H NMR (400 MHz, CDCl3): δ ppm 7.12 (d, J = 8.4
Hz, 2H), 6.64 (d, J = 8.4 Hz, 2H), 3.38-3.33 (m, 1H), 3.11-3.05
(m, 1H), 2.82 (br.s, 1H), 2.13-2.07 (m, 2H), 1.78-1.72 (m, 2H),
1.44-1.25 (m, 3H), 1.09-1.01 (m, 1H); 13C NMR (100 MHz,
CDCl3) δ ppm 146.62, 129.33, 123.03, 115.61, 74.73, 60.54,
33.41, 31.71, 25.14, 24.43; Ms (EI) m/z = 225.1 [M]+.
1
2-(2-fluorophenylamino)cyclohexanol(4g):23c Colorless oil; H
NMR (400 MHz, CDCl3): δ ppm 6.97-6.93 (m, 2H), 6.87 (t, J =
8.2 Hz, 1H), 6.67-6.64 (m, 1H), 3.45-3.39 (m, 1H), 3.15-3.12 (m,
1H), 2.71 (br.s, 1H), 2.15-2.04 (m, 2H), 1.78-1.72 (m, 2H), 1.43-
1.24 (m, 3H), 1.17-1.07 (m, 1H); 13C NMR (100 MHz, CDCl3) δ
ppm 153.70, 136.34, 124.84, 124.80, 117.91, 117.84, 115.04,
114.85, 114.07, 74.75, 60.13, 33.35, 31.90, 25.22, 24.43; Ms (EI)
m/z = 209.1 [M]+.
1
1-(phenylamino)propan-2-ol (4q):6 Colorless oil; H NMR (400
MHz, CDCl3): δ ppm 7.12 (d, J = 8.8 Hz, 2H), 6.56 (d, J = 8.8
Hz, 2H), 4.04-3.99 (m, 1H), 3.21-3.17 (m, 1H), 2.97-2.94 (m,
1H), 2.64 (s, 1H), 1.27-1.18 (m, 3H); Ms (EI) m/z = 151.1 [M]+.
1
1-((4-chlorophenyl)amino)propan-2-ol (4r):6 Colorless oil; H
NMR (400 MHz, CDCl3): δ ppm 7.26-7.16 (m, 2H), 6.76-6.65
(m, 3H), 4.05-4.00 (m, 1H), 3.26-3.22 (m, 1H), 3.03-2.98 (m,
1H), 2.68 (s, 1H), 1.27-1.18 (m, 3H); Ms (EI) m/z = 185.1 [M]+.
2-(4-Trifluoromethyloxyphenylamino)cyclohexanol (4h): 6 White
o
1
solid, M.p.: 71-72 C; H NMR (400 MHz, CDCl3): δ ppm 7.03
(d, J = 8.8 Hz, 2H), 6.67 (d, J = 9.2 Hz, 2H), 3.40-3.34 (m, 1H),
3.09-3.06 (m, 2H), 2.65 (br.s, 1H), 2.12 (t, J = 9.2 Hz, 2H), 1.79-
1.72 (m, 2H), 1.41-1.26 (m, 3H), 1.12-1.01 (m, 1H); Ms (EI) m/z
= 275.1 [M]+.
1
2-(piperidin-1-yl)cyclohexanol(4s):6 Colorless oil; H NMR (400
MHz, CDCl3): δ ppm 3.37 (s, 3H), 2.91-2.87 (m, 1H), 2.69 (s,
1H), 2.12-2.05 (m, 1H), 1.98-1.94 (m, 1H), 1.71-1.65 (m, 2H),
1.27-1.18 (m, 3H), 1.09-0.99 (m, 1H); 13C NMR (100 MHz,
CDCl3): δ ppm70.99, 68.54, 32.26, 26.72, 25.62, 24.83, 24.11,
22.15; Ms (EI) m/z = 183.1 [M]+.
2-morpholinocyclohexanol(4t):6 Colorless oil; 1H NMR (400
MHz, CDCl3): δ ppm 3.81 (s, 1H), 3.64-3.58 (m, 4H), 3.32-3.27
(m, 1H), 2.67-2.62 (m, 2H), 2.35-2.30 (m, 2H), 2.32-2.03 (m,
2H), 1.76-1.63 (m, 3H), 1.61-1.04 (m, 4H); 13C NMR (100 MHz,
CDCl3): δ ppm 70.46, 68.33, 67.44, 33.13, 25.40, 23.97, 22.18;
Ms (EI) m/z = 185.1 [M]+.
2-(3-Nitrophenylamino)cyclohexanol (4i):23a White solid, M.p.:
o
1
1
77-79 C; H NMR (400 MHz, CDCl3): δ ppm H NMR (400
MHz, CDCl3): δ ppm 7.55-7.50 (m, 2H), 7.30-7.27 (m, 1H),
6.98-6.96 (m, 1H), 3.85 (br.s, 1H), 3.45-3.40 (m, 1H), 3.25-3.19
(m, 1H), 2.37 (s, 1H), 2.13 (t, J = 7.2 Hz, 2H), 1.82-1.74 (m,
2H), 1.46-1.28 (m, 3H), 1.17-1.08 (m, 1H); Ms (EI) m/z = 236.1
[M]+.
2-(naphthalen-1-yl-amino) cyclohexanol(4j):5 Brown solid, M.p.:
o
1
174-176 C; H NMR (400 MHz, CDCl3): δ ppm 7.88-7.80 (m,
2H), 7.47-7.32 (m, 4H), 6.90-6.88 (m, 1H), 3.64-3.58 (m, 1H),
3.41-3.35 (m, 1H), 2.94 (s, 1H), 2.25-2.16 (m, 2H), 1.80-1.75
(m, 2H), 1.47-1.30 (m, 1H), 1.26-1.20 (m, 1H), Ms (EI) m/z =
241.2 [M]+.
1
4.2.2 6a-6g are known compounds, and the H NMR, 13C NMR
spectral data are summarized as follows:
2-methoxycyclohexanol (6a):12 Colorless oil; 1H NMR (400
MHz, CDCl3): δ ppm 3.37 (s, 3H), 2.91-2.87 (m, 1H), 2.69 (s,
1H), 2.12-2.05 (m, 1H), 1.98-1.94 (m, 1H), 1.71-1.65 (m, 2H),
1.27-1.18 (m, 3H), 1.09-0.99 (m, 1H); 13C NMR (100 MHz,
CDCl3): δ ppm 84.98, 73.71, 56.29, 32.09, 28.35, 24.12, 23.95;
Ms (EI) m/z = 130.1 [M]+.
1
2-phenyl-2-(phenylamino)ethanol(4k):6 Colorless oil; H NMR
(400 MHz, CDCl3): δ ppm 7.42-7.36 (m, 4H), 7.33-7.30 (m, 1H),
7.18-7.13 (m, 2H), 6.73 (t, J = 8.0 Hz, 2H), 6.62 (d, J = 8.0 Hz,
2H), 4.53 (q, J = 7.2 Hz, 1H), 3.95 (dd, J = 11.2 Hz, 4.0 Hz, 1H),
3.76 (dd, J = 11.2 Hz, 4.0 Hz, 1H); 13C NMR (100MHz, CDCl3)
δ ppm 147.26, 140.18, 129.19, 128.84, 127.62, 126.78, 117.95,
113.94, 67.33, 59.96; Ms (EI) m/z = 213.1 [M]+.
2-ethoxycyclohexanol (6b):10 Colorless oil; H NMR (400 MHz,
1
CDCl3): δ ppm 3.72-3.66 (m, 1H), 3.43-3.35 (m, 2H), 3.02-2.96
(m, 1H), 2.70 (s, 1H), 2.08-1.95 (m, 3H), 1.75-1.64 (m, 3H),
1.43-1.33 (m, 2H), 1.18 (t, J = 7.0 Hz, 3H); 13C NMR (100 MHz,
CDCl3): δ ppm 83.45, 73.72, 64.01, 32.98, 29.22, 24.25, 23.96,
15.61; Ms (EI) m/z = 144.1 [M]+.
1
2-phenyl-2-(p-tolylamino)ethanol(4l):6 Colorless oil; H NMR
(400 MHz, CDCl3): δ ppm 7.41-7.27 (m, 5H), 6.94 (d, J = 8.4
Hz, 2H), 6.62 (d, J = 8.4 Hz, 2H), 4.53 (q, J = 7.2 Hz, 1H), 3.95
(dd, J = 11.2 Hz, 4.4 Hz, 1H), 3.75 (dd, J = 11.2 Hz, 4.0 Hz, 1H),
2.23 (s, 3H); 13C NMR (100MHz, CDCl3) δ ppm 144.91, 140.32,
129.66, 128.79, 127.55, 127.17, 126.75, 114.10, 67.35, 60.25,
20.36; Ms (EI) m/z = 227.1 [M]+.
2-((4-chlorophenyl)amino)-2-phenylethanol(4m):6 Colorless oil;
1H NMR (400 MHz, CDCl3): δ ppm 7.37-7.27 (m, 5H), 7.05 (d,
J = 9.2 Hz, 2H), 6.49 (d, J = 8.8 Hz, 2H), 4.67 (dd, J = 6.8 Hz,
4.0 Hz, 1H), 3.96 (dd, J = 11.2 Hz, 4.0 Hz, 1H), 3.76 (dd, J =
11.2 Hz, 4.0 Hz, 1H); 13C NMR (100MHz, CDCl3) δ ppm
2-isopropoxycyclohexanol (6c):12 Colorless oil; H NMR (400
1
MHz, CDCl3): δ ppm 3.67-3.60 (m, 1H), 3.41-3.33 (m, 1H),
3.11-3.04 (m, 1H), 2.77 (d, J = 10.4 Hz, 1H), 2.02-1.97 (m, 3H),
1.74-1.65 (m, 3H), 1.41-1.34 (m, 2H), 1.18-1.16 (m, 6H); 13C
NMR (100 MHz, CDCl3): δ ppm 81.35, 73.76, 70.33, 33.11,
28.69, 24.38, 23.76, 23.75, 22.24; Ms (EI) m/z = 158.1 [M]+.
2-(tert-butoxy)cyclohexanol (6d):12 Colorless oil; H NMR (400
1
MHz, CDCl3): δ ppm 3.83 (s, 1H), 2.49-2.43 (m, 1H), 3.22-3.15
(m, 1H), 2.12-1.84 (m, 4H), 1.72-1.65 (m, 4H), 1.19 (s, 9H); 13
C

6
ACCEPTED MANUSCRIPT
NMR (100 MHz, CDCl3): δ ppm 85.90, 75.22, 72.77, 33.25,
7354-7357.
32.80, 29.70, 24.60, 24.08; Ms (EI) m/z = 172.1 [M]+.
[8] Pachón, L. D.; Gamez, P.; Brussel. J. J. M.; Reedijk, J.
Tetrahedron Lett. 2003, 44, 6025-6027.
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Catal. Lett. 2003, 89, 95-97.
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3269-3272.
1
2-methoxy-2-phenylethanol (6e):23b Colorless oil; H NMR (400
MHz, CDCl3): δ ppm 7.39-7.32 (m, 5H), 4.32 (q, J = 8.4 Hz,
1H), 3.72-3.63 (m, 2H), 3.33 (s, 3H), 2.87 (s, 1H); 13C NMR
(100 MHz, CDCl3): δ ppm 138.39, 128.53, 128.12, 126.90,
84.80, 67.31, 56.88; Ms (EI) m/z = 152.1 [M]+
1
2-ethoxy-2-phenylethanol (6f):23b Colorless oil; H NMR (400
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González, J. M. Org. Lett. 2002, 4, 2817-2819; (b) Kamal,
A.; Ramu, R.; Azhar, M. A.; Khanna, R. G. B. Tetrahedron
Lett. 2005, 46, 2675-2677.
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1995, 117, 1651-1652; (b) Arias, O.; Petrov, A. R.;
Bannenberg, T.; Altenburger, K.; Arndt, P.; Jones, P. G.;
Rosenthal, U.; Tamm, M. Organometallics. 2014, 33, 1774-
1786; (c) Baldwin, S. M.; Bercaw, J. E.; Britzinger, H. H. J.
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Alvarez-Rodrigo, L.; Rodriguez, F.; Fananas, F. J. Org.
Lett. 2007, 9, 3081-3084.
MHz, CDCl3): δ ppm 7.39-7.30 (m, 5H), 4.43 (q, J = 8.4 Hz,
1H), 3.70-3.51 (m, 2H), 3.48-3.40 (m, 2H), 2.75 (s, 1H), 1.24 (t,
J = 7.0 Hz, 1H); 13C NMR (100 MHz, CDCl3): δ ppm 138.39,
128.53, 128.12, 126.90, 84.80, 67.31, 56.88; Ms (EI) m/z = 166.1
[M]+
1
2-butoxy-2-phenylethanol (6g):23b Colorless oil; H NMR (400
MHz, CDCl3): δ ppm 7.40-7.28 (m, 5H), 4.41 (q, J = 8.4 Hz,
1H), 3.68-3.61 (m, 2H), 3.48-3.34 (m, 2H), 2.53 (s, 1H), 1.61-
1.57 (m, 2H), 1.44-1.35 (m, 2H), 0.93 (t, J = 7.4 Hz, 1H); 13C
NMR (100 MHz, CDCl3): δ ppm 139.07, 128.47, 127.98, 126.80,
82.92, 68.97, 67.46, 31.95, 19.36, 13.88; Ms (EI) m/z = 194.1
[M]+.
[14] Yamamoto, H. Lewis Acids in Organic Synthesis, ed.
Wiley-VCH, Weinheim, 2000.
Supporting Information: The crystal data of complex, copies
of the 1H NMR and 13C NMR of all the products.
[15] (a) Chen, J.; Otera, J. Angew. Chem. Int. Ed. 1998, 37, 91-93;
(b) Li, X.; Kurita, A.; Man-e, S.; Orita, A.; Otera, J.
Organometallics 2005, 24, 2567-2569; (c) An, D. L.; Peng, Z.
H.; Orita, A.; Kurita, A.; Man-e, S.; Ohkubo, K.; Li, X.;
Fukuzumi, S.; Otera, J. Chem. Eur. J. 2006, 12, 1642-1647.
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Yin, S. F. Chem. Eur. J. 2012, 18, 6172-6182; (b) Qiu, R. H.;
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Q. T.; Peng, L. F.; Xu, X. H.; Li, J.; Qiu, R. H.; Au, C. T. Green
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Xu, X. H.; Chen, J. Y.; Zhang, X. H.; Chen, S. H.; Yin, S. F.
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CCDC No. 1565685 contains the supplementary
crystallographic data for this paper. These data can be obtained
free of charge from the cambridge Crystallographic Data Centre
viawww.ccdc.cam.ac.uk/ata_request/cif.
Acknowledgements
The authors thank the National Natural Science Foundation
of China (21536003, 21273068), Shanxi Province Science
Foundation for Youths (201701D221035), and the PhD Start-up
Foundation of Shanxi Medical University (03201501) for
financial support.
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