One-pot method for stereoselective cyclopropanation of electron-deficient olefins with methyl bromoacetate and phenacyl bromide in the presence of triphenylarsine

Article abstract of DOI:10.1055/s-2005-916035

A triphenylarsine-catalyzed one-pot procedure for the preparation of cis-cyclopropanes with acyclic electron-deficient olefins with carbonyl-stabilized arsonium ylides formed from methyl bromoacetate or phenacyl bromide in the presence of NaHCO₃

Full text of DOI:10.1055/s-2005-916035

2718
PAPER
One-Pot Method for Stereoselective Cyclopropanation of Electron-Deficient
Olefins with Methyl Bromoacetate and Phenacyl Bromide in the Presence of
Triphenylarsine
S
tereoselective
h
C
yclopropan
o
ation of Elec
n
tron-Deficie
g
nt
O
lefins jiao Ren,*a Weiguo Cao,a,b Weiyu Ding,a Yu Wanga
a
Department of Chemistry, Shanghai University, Shanghai, 200444, P. R. of China
Fax +86(21)66134856; E-mail: renrui198229@hotmail.com
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences,
Shanghai, 200032, P. R. of China
b
Received 6 April 2005; revised 18 May 2005
from triphenylarsine and halogen compound; (2) the con-
version of arsonium salt to ylide in the presence of the
base; and (3) the cyclopropanation of ylide and olefin. In
this multistep operation, each step requires its own condi-
Abstract: A triphenylarsine-catalyzed one-pot procedure for the
preparation of cis-cyclopropanes with acyclic electron-deficient
olefins with carbonyl-stabilized arsonium ylides formed from meth-
yl bromoacetate or phenacyl bromide in the presence of NaHCO3
has been achieved. This method is simple, high-yielding and cis-se- tion, reagent and solvent. After each reaction is complet-
lective. The success of this method depends on the choice of base,
solvent and temperature.
ed, the solvent and waste are separated and the product is
purified. The improvements of the efficiency of organic
Key words: one-pot, triphenylarsine, cyclopropanation, stereose-
lectivity, NaHCO3
processes and the reduction of the amount of reagents and
solvents have been major goals in synthetic chemistry. Up
to now the development of a new one-step process for the
stereoselective preparation of cis-cyclopropane using acy-
The search for efficient methods for the preparation of cy- clic olefin as substrate has remained a challenge.
clopropane has been attracting organic chemists, because
The other shortcoming of cyclopropanation involving ar-
of the unique structure and reactivity of cyclopropanes.
sonium ylide is that triphenylarsine is expensive and tox-
Cyclopropanes have been used as building blocks for the
ic. One way to solve this problem is to use triphenylarsine
synthesis of natural and artificial products and are also
as a catalyst in the process of preparing cyclopropane, but
found as a basic structural unit in a wide range of naturally
in the literature on cyclopropanation via MIRC, tellurium
occurring biologically active compounds in plants and
has been reported as the catalyst.9 Here we report a new
microorganisms.1 The reaction involving ylides and elec-
triphenylarsine-catalyzed one-pot procedure for cyclopro-
tron-deficient olefins, Michael-initiated ring closure
panation using bromides and acyclic olefins as the starting
(MIRC), is one of the most important methods for prepa-
material in the presence of the NaHCO3 with high yield
and cis-selectivity (Scheme 1).
ration of cyclopropane.2 A highly stereoselective cyclo-
propanation via MIRC has been reported for cyclic
olefins.3 Although there have been a few examples of cis-
H
selective cyclopropanation,4 most of the reactions via
MIRC with acyclic olefins as substrates yield a mixture of
cis and trans isomers or thermodynamically stable trans-
cyclopropanes.2,5 The stereoselective preparation of cis-
cyclopropane from acyclic olefin is still a real problem.
X
NaHCO3
X
H
Ph3As + BrCH2COR + ArCH=C(X)2
Ar
CHCl3, reflux
11
22
33
O
O
COR
Huang and coworkers first reported a method for the ste-
reoselective synthesis of cyclopropane with arsonium
ylide and olefin.6 Later, Ding and coworkers reported a
process for the highly stereoselective synthesis of cis-1,2-
cyclopropane with arsonium salt and olefin as the starting
material.7 Our group has investigated stereoselective cy-
clopropanation with arsonium salts and olefins.8 Although
these methods with acyclic olefin as the substrate are sat-
isfactory for stereoselectivity, they involve a two- or
three-step reaction. The total process consists of the fol-
lowing sequence: (1) the preparation of arsonium salt
44
R = Ph, OCH3
X = CN,
X2 =
O
O
Scheme 1
For the preparation of cyclopropane from arsonium salt
and olefin, the base is essential. The first base tested was
K2CO3 which was used in our earlier method with arsoni-
um salt and olefin.7,8 In the initial model experiment, a
mixture of triphenylarsine (0.5 equiv), phenacyl bromide
(1.2 equiv), 4-methoxyphenylidenemalononitrile (1.0
equiv) and K2CO3 (3.0 equiv) in DME (5 mL) was stirred
at room temperature. Unfortunately, the expected cyclo-
propane was not observed by TLC and the color of the so-
SYNTHESIS 2005, No. 16, pp 2718–2722
x
x.
x
x
.
2
0
0
5
Advanced online publication: 23.09.2005
DOI: 10.1055/s-2005-916035; Art ID: F06505SS
© Georg Thieme Verlag Stuttgart · New York

PAPER
Stereoselective Cyclopropanation of Electron-Deficient Olefins
2719
lution became deep brown. Based on our previous ences in the yield of cyclopropanation are not significant,
experience, NaHCO3 was employed instead of K2CO3. but the differences in the rate of reaction are great. For ex-
The reaction was carried out under the same conditions as ample, a catalytic amount of triphenylarsine (0.1 equiv)
in the model text above and the desired product was de- showed good catalytic activity with 81% yield, but it took
tected by TLC. After 170 hours, 1-benzoyl-2-(4-methoxy- 68 hours to complete the reaction (Table 2, entry 1). The
phenyl)-3,3-dicyanocyclopropane was obtained in 51% yield was 88% and time of reaction was 9 hours when 1
yield, but the cyclopropanation reaction was not complet- equivalent of triphenylarsine was used as catalyst
ed, because there was residual 4-methoxyphenylidenema- (Table 2, entry 5). To achieve a satisfactory reaction rate,
lononitrile in the solution. To our knowledge, this is the 0.5 equivalent of triphenylarsine was used in optimal con-
first report of the use of NaHCO3 as a base in the produc- dition.
tion of arsonium ylide from arsonium salt.
Table 2 Yields of Cyclopropanes and Rates of Reaction with Vari-
For the above result, it is necessary to carry out the reac-
tion at an increased temperature to achieve a satisfactory
reaction rate and yield. Our studies began with the same
model system using 0.5 equivalent of triphenylarsine with
NaHCO3 as base and DME as solvent. The results
(Table 1, entries 1–3), show that the yield of the reaction
increased and the time of the reaction decreased when the
temperature was raised from room temperature to 50 °C,
but the yield decreased when reaction was carried out at
60 °C (Table 1, entry 4). At 60 °C, some unknown side-
products were generated. A further search for a suitable
solvent was performed at 50 °C. The results in Table 1
demonstrated that chloroform was the best solvent among
those tested (Table 1, entry 8). When the reaction was car-
ried out in refluxing CHCl3 (Table 1, entry 9), the yield
reached 88% and the reaction took 18 hours.
ous Amounts of Triphenylarsinea
Entry
Triphenylarsine (equiv) Time (h)
Yield (%)b
1
2
3
4
5
0.1
68
30
18
12
9
81
85
88
88
88
0.25
0.5
0.75
1.0
a Unless otherwise specified, the reaction was carried out with phen-
acyl bromide (1.2 equiv), 4-methoxyphenylidenemalononitrile (1.0
equiv), and NaHCO3 (3.0 equiv) in refluxing CHCl3.
b Yield of isolated product.
The scope of the triphenylarsine-catalyzed cyclopropana-
tion with other bromide and electron-deficient olefin was
further explored. In each case, high yields of cis-cyclopro-
panes were obtained under the aforementioned optimal
condition (Table 3).
Table 1 Results of the Optimization of Solvent and Temperaturea
Entry
Solvent
DME
Temp (°C) Time (h)
Yield (%)b
1
2
r.t.
40
170
120
84
51
59
70
66
58
62
71
86
88
83
63
In our experiments, the arsonium salts were observed by
TLC. The cis-cyclopropane 4e was produced in a yield of
84% when a mixture of arsonium salt (1 mmol), 4-meth-
oxyphenylidenemalononitrile (1 mmol) and NaHCO3 (3
mmol) was refluxed in CHCl3 for seven hours. On the ba-
sis of experimental observation and the literature, the
mechanism of this reaction is likely to proceed via a cyclic
process involving the formation of arsonium salt from
triphenylarsine and bromide followed by the production
of ylide in the presence of NaHCO3, and the MIRC of
ylide and olefin generating the cis-cyclopropane and
triphenylarsine. This cyclic process is depicted in
Scheme 2.
DME
3
DME
50
4
DME
60
50
5
dioxane
THF
50
72
6
50
72
7
benzene
CHCl3
CHCl3
CHCl3
CHCl3
50
84
8
50
64
9
reflux
40
18
10
11
110
240
r.t.
H
X
a Unless otherwise specified, the reaction was carried out with Ph3As
(0.5 equiv), phenacyl bromide (1.2 equiv), 4-methoxyphenylidene-
malononitrile (1.0 equiv), and NaHCO3 (3.0 equiv).
b Yield of isolated product.
H
X
BrCH2COR
Ar
Ph3As
COR
ArCH=C(X)2
Ph3As=CHCOR
_
Ph3AsCH2CORBr
+
We investigated the relationship of the yield and the rate
of the reaction to the amount of triphenylarsine used in re-
fluxing CHCl3. Various amounts of triphenylarsine as cat-
alyst in refluxing CHCl3 were tested. The results are
shown in Table 2. When the amount of triphenylarsine is
increased from 0.1 equivalent to 1 equivalent, the differ-
NaHCO3
Scheme 2
Synthesis 2005, No. 16, 2718–2722 © Thieme Stuttgart · New York

2720
Z. Ren et al.
PAPER
Table 3 Triphenylarsine-Catalyzed Cyclopropanation with Bromides and Olefinsa
Entry
1
Product
4a
Ar
R
X
Time (h)
16
Yield (%)b
4-NO2C6H4
4-FC6H4
4-ClC6H4
4-MeC6H4
4-MeOC6H4
Ph
Ph
CN
82
83
88
90
88
88
87
89
82
84
80
83
76
74
2
4b
4c
Ph
CN
16
3
Ph
CN
18
4
4d
4e
Ph
CN
18
5
Ph
CN
18
6
4f
Ph
CN
18
7
4g
2-ClC6H4
2,4-Cl2C6H3
3,4-(OCH2O)C6H3
2,4-(MeO)2C6H3
4-ClC6H4
4-MeC6H4
Ph
Ph
CN
18
8
4h
4i
Ph
CN
18
9
Ph
CN
22
10
11
12
13
14
4j
Ph
CN
30
4k
4l
OMe
OMe
Ph
CN
120
120
45
CN
4m
4n
Meldrum’s acid
Meldrum’s acid
Ph
OMe
60
a Unless otherwise specified, the reaction was carried out with Ph3As (0.5 equiv), phenacyl bromide (1.2 equiv), arylidenemalononitrile (1.0
equiv), and NaHCO3 (3.0 equiv) in refluxing CHCl3.
b Yield of isolated product.
fluxing CHCl3. The completion of the reaction was determined by
TLC. The CHCl3 was removed under reduced pressure and the res-
idue was eluted on a silica gel chromatographic column. Ph3As can
be recovered and the desired products 4 obtained, respectively.
The structures of products 4a–n were determined by IR,
1H NMR spectroscopy. The cis configurations of the com-
pounds 4a–n were confirmed by comparison of the cou-
pling constant of two protons situated at adjacent carbon
atoms in the cyclopropane ring. It has been reported that
the cyclopropyl protons with a cis relationship have larger
coupling constants (~ 7–10 Hz), while those with a trans
relationship have smaller coupling constants (~ 3–7 Hz).10
The coupling constants of cyclopropanes 4a–n (Table 3)
were 8.0–9.6 Hz.
cis-1-Benzoyl-3,3-dicyano-2-(4-nitrophenyl)cyclopropane (4a)
Colorless solid; mp 185–186 °C (hexane–EtOAc) (Lit.8c mp 188–
189 °C).
IR (KBr): 3073, 2254, 1674, 1595 cm–1.
1H NMR (300 MHz, CDCl3): d = 4.02 (d, J = 8.0 Hz, 1 H), 4.11 (d,
J = 8.0 Hz, 1 H), 7.59–7.66 (m, 3 H), 7.75–7.78 (t, J = 7.8 Hz, 2 H),
8.12 (d, J = 8.0 Hz, 2 H), 8.34 (d, J = 8.4 Hz, 2 H).
We have achieved a triphenylarsine-catalyzed one-step
procedure for the preparation of cis-cyclopropane with
acyclic electron deficient olefins and methyl bromoace-
tate and phenacyl bromide in the presence of NaHCO3.
This method is simple, high-yielding and cis-selective.
The success of this method depends on the choice of base,
solvent and temperature. Further exploration of the scope
of the triphenylarsine-catalyzed process is in progress.
cis-1-Benzoyl-3,3-dicyano-2-(4-fluorophenyl)cyclopropane (4b)
Colorless solid; mp 158–159 °C (hexane–EtOAc) (Lit.8c mp 156–
157 °C).
IR (KBr): 3065, 2251, 1662, 1596 cm–1.
1H NMR (300 MHz, CDCl3): d = 3.91 (d, J = 8.0 Hz, 1 H), 4.01 (d,
J = 8.0 Hz, 1 H), 7.14–7.20 (t, J = 8.1 Hz, 2 H), 7.37–7.41 (q, J =
7.1 Hz, 2 H), 7.59–7.64 (t, J = 8.5 Hz, 2 H), 7.72–7.78 (t, J = 8.1 Hz,
1 H), 8.09–8.13 (d, J = 8.2 Hz, 2 H).
All reagents and solvents were obtained from commercial source
and used without purification. Melting points were determined on
WRS-1 digital melting point apparatus made by Shanghai physical
instrument factory (SPOIF), China and are uncorrected. IR spectra
were measured in KBr on a PE-580B spectrometer. 1H NMR spec-
tra were recorded at a Bruker AM-300, using CDCl3 as solvent and
TMS as internal reference.
cis-1-Benzoyl-2-(4-chlorophenyl)-3,3-dicyanocyclopropane (4c)
Colorless solid; mp 179–180 °C (hexane–EtOAc) (Lit.8c mp 181–
182 °C).
IR (KBr): 3036, 2247, 1675, 1595 cm–1.
1H NMR (300 MHz, CDCl3): d = 3.89 (d, J = 8.0 Hz, 1 H), 4.00 (d,
J = 8.0 Hz, 1 H), 7.34 (d, J = 8.5 Hz, 2 H), 7.45 (d, J = 8.7 Hz, 2 H),
7.58–7.64 (t, J = 8.0 Hz, 2 H), 7.72–7.77 (t, J = 7.0 Hz, 1 H), 8.08–
8.11 (d, J = 7.4 Hz, 2 H).
cis-1-Acyl-2-arylcyclopropanes 4a–n; General Procedure
A mixture of Ph3As (1; 0.145 g, 0.5 mmol), bromide 2 (1.2 mmol),
olefin 3 (1 mmol) and NaHCO3 (0.240 g, 3 mmol) was stirred in re-
Synthesis 2005, No. 16, 2718–2722 © Thieme Stuttgart · New York

PAPER
Stereoselective Cyclopropanation of Electron-Deficient Olefins
2721
cis-1-Benzoyl-3,3-dicyano-2-(4-methylphenyl)cyclopropane
1H NMR (300 MHz, CDCl3): d = 3.60 (d, J = 8.2 Hz, 1 H), 3.82 (s,
3 H), 3.91 (s, 3 H), 3.97 (d, J = 8.2 Hz, 1 H), 6.47–6.53 (m, 2 H),
7.04–7.07 (d, J = 8.2 Hz, 1 H), 7.59–7.61 (t, J = 6.8 Hz, 2 H), 7.69–
7.74 (t, J = 6.9 Hz, 1 H), 8.08–8.11 (d, J = 7.9 Hz, 2 H).
(4d)
Colorless solid; mp 156–157 °C (hexane–EtOAc) (Lit.8c mp 157–
158 °C).
IR (KBr): 3035, 2247, 1677, 1595 cm–1.
cis-2-(4-Chlorophenyl)-3,3-dicyano-1-methoxycarbonylcyclo-
1H NMR (300 MHz, CDCl3): d = 2.38 (s, 3 H), 3.86 (d, J = 8.0 Hz,
1 H), 4.03 (d, J = 8.0 Hz, 1 H), 7.26 (s, 4 H), 7.56–7.62 (t, J = 8.0
Hz, 2 H), 7.70–7.72 (t, J = 7.5 Hz, 1 H), 8.08–8.11 (d, J = 7.4 Hz, 2
H).
propane (4k)
Colorless solid; mp 124–125 °C (hexane–EtOAc) (Lit.8b mp 128–
130 °C).
IR (KBr): 3051, 2250, 1737, 1597 cm–1.
cis-1-Benzoyl-3,3-dicyano-2-(4-methoxyphenyl)cyclopropane
1H NMR (300 MHz, CDCl3): d = 3.12 (d, J = 8.2 Hz, 1 H), 3.66 (d,
J = 8.0 Hz, 1 H), 3.92 (s, 3 H), 7.26 (d, J = 8.5 Hz, 2 H), 7.43 (d,
J = 8.5 Hz, 2 H).
(4e)
Colorless solid; mp 163–164 °C (hexane–EtOAc) (Lit.8c mp 161–
162 °C).
cis-3,3-Dicyano-1-methoxycarbonyl-2-(4-methylphenyl)cyclo-
IR (KBr): 3065, 2246, 1675, 1595 cm–1.
propane (4l)
1H NMR (300 MHz, CDCl3): d = 3.83 (s, 3 H), 3.86 (d, J = 8.0 Hz,
1 H), 4.00 (d, 1 H, J = 8.0 Hz, 1 H), 6.97 (d, J = 8.8 Hz, 2 H), 7.30
(d, J = 8.6 Hz, 2 H), 7.58–7.63 (t, J = 8.0 Hz, 2 H), 7.71–7.74 (t,
J = 7.4 Hz, 1 H), 8.09–8.12 (d, J = 7.4 Hz, 2 H).
Colorless solid; mp 90–91 °C (hexane–EtOAc) (Lit.8b mp 84–
86 °C).
IR (KBr): 3053, 2247, 1738, 1610 cm–1.
1H NMR (300 MHz, CDCl3): d = 2.37 (s, 3 H), 3.13 (d, J = 8.2 Hz,
1 H), 3.66 (d, J = 8.2 Hz, 1 H), 3.91 (s, 3 H), 7.17 (d, J = 8.2 Hz, 2
H), 7.23 (d, J = 8.2 Hz, 2 H).
cis-1-Benzoyl-3,3-dicyano-2-phenylcyclopropane (4f)
Colorless solid; mp 134–135 °C (hexane–EtOAc) (Lit.8c mp 132–
133 °C).
cis-1-Benzoyl-6,6-dimethyl-2-phenyl-5,7-dioxaspiro[2,5]oc-
tane-4,8-dione (4m)
IR (KBr): 3043, 2243, 1681, 1596 cm–1.
1H NMR (300 MHz, CDCl3): d = 3.91 (d, J = 8.0 Hz, 1 H), 4.06 (d,
J = 8.0 Hz, 1 H), 7.38–7.45 (m, 5 H), 7.5–7.60 (t, J = 7.7 Hz, 2 H),
7.69–7.74 (t, J = 7.4 Hz, 1 H), 8.08–8.11 (d, J = 7.1 Hz, 2 H).
Colorless solid; mp 182–183 °C (hexane–EtOAc) (Lit.8a mp 184–
185 °C).
IR (KBr): 3003, 1744, 1693, 1594 cm–1.
cis-1-Benzoyl-2-(2-chlorophenyl)-3,3-dicyanocyclopropane (4g)
Colorless solid; mp 156–157 °C (hexane–EtOAc) (Lit.8c mp 154–
155 °C).
IR (KBr): 3060, 2249, 1674, 1597 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.71 (s, 3 H), 1.74 (s, 3 H), 4.11
(d, J = 9.6 Hz, 1 H), 4.44 (d, J = 9.6 Hz, 1 H), 7.37–7.42 (m, 5 H),
7.47–7.52 (t, J = 6.6 Hz, 2 H), 7.58–7.64 (t, J = 6.3 Hz, 1 H), 8.00–
8.03 (d, J = 7.2 Hz, 2 H).
1H NMR (300 MHz, CDCl3): d = 3.97 (d, J = 8.2 Hz, 1 H), 4.03 (d,
J = 8.2 Hz, 1 H), 7.26–7.39 (m, 3 H), 7.44–7.78 (m, 4 H), 8.12–8.15
(d, J = 7.4 Hz, 2 H).
cis-1-Methoxycarbonyl-6,6-dimethyl-2-phenyl-5,7-dioxa-
spiro[2,5]octane-4,8-dione (4n)
Colorless solid; mp 146–147 °C (hexane–EtOAc) (Lit.7 mp 149–
150 °C).
cis-1-Benzoyl-3,3-dicyano-2-(2,4-dichlorophenyl)cyclopropane
IR (KBr): 3010, 1743 cm–1.
(4h)
Colorless solid; mp 142–143 °C (hexane–EtOAc) (Lit.8c mp 141–
142 °C).
1H NMR (300 MHz, CDCl3): d = 1.71 (s, 3 H), 1.76 (s, 3 H), 3.82
(s, 3 H), 3.85 (d, J = 9.3 Hz, 1 H), 3.94 (d, J = 9.3 Hz, 1 H), 7.30–
7.37 (m, 5 H).
IR (KBr): 3072, 2247, 1681, 1597 cm–1.
1H NMR (300 MHz, CDCl3): d = 3.92 (d, J = 8.2 Hz, 1 H), 3.99 (d,
J = 8.2 Hz, 1 H), 7.21–7.27 (t, J = 8.4 Hz, 2 H), 7.34–7.37 (d, J =
8.5 Hz, 1 H), 7.60–7.67 (m, 2 H), 7.75–7.80 (t, J = 7.7 Hz, 1 H),
8.12–8.15 (d, J = 7.4 Hz, 2 H).
Acknowledgment
We gratefully acknowledge the help of Dr. Anthony G. Netting and
Dr. Nancy Lynn Netting for polishing the manuscript. Thanks are
due to the National Natural Science Foundation of China for finan-
cial support.
cis-1-Benzoyl-3,3-dicyano-2-(3,4-methylenedioxyphenyl)cyclo-
propane (4i)
Colorless solid; mp 187–188 °C (hexane–EtOAc) (Lit.8c mp 188–
189 °C).
References
IR (KBr): 3050, 2248, 1672, 1595 cm–1.
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Colorless solid; mp 149-151 °C (hexane–EtOAc) (Lit.8c mp 150–
151 °C).
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Z. Ren et al.
PAPER
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