Methyl (E)-2-(2-phenylcyclopropylidene)acetate: Synthesis, isomerization, and reaction with 1,3-diphenyl-2-benzofuran

Article abstract of DOI:10.1134/S1070428013040064

Treatment of 3-methyl-2-phenylcycloprop-2-ene-1-carboxylic acid with potassium tert-butoxide induced its isomerization into trans-2-methylidene-3- phenylcyclopropane-1-carboxylic acid which was converted into methyl ester, and heating of the latter for 1

Full text of DOI:10.1134/S1070428013040064

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2013, Vol. 49, No. 4, pp. 530–535. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © A.P. Molchanov, T.Q. Tran, A.V. Stepakov, V.V. Gurzhii, R.R. Kostikov, 2013, published in Zhurnal Organicheskoi Khimii, 2013,
Vol. 49, No. 4, pp. 547–551.
Dedicated to the 100th Anniversary of Corresponding Member
of the Russian Academy of Sciences A.A. Petrov
Methyl (E)-2-(2-Phenylcyclopropylidene)acetate: Synthesis,
Isomerization, and Reaction with 1,3-Diphenyl-2-benzofuran
A. P. Molchanova, T. Q. Tranb, A. V. Stepakova, V. V. Gurzhiia, and R. R. Kostikova
a St. Petersburg State University, Universitetskii pr. 26, St. Petersburg, 198504 Russia
e-mail: s.lab@pobox.spbu.ru
b Hanoi University of Science and Technology, 1 Dai Co Viet Road, Ha Noi, Viet Nam
Received February 2, 2013
Abstract—Treatment of 3-methyl-2-phenylcycloprop-2-ene-1-carboxylic acid with potassium tert-butoxide in-
duced its isomerization into trans-2-methylidene-3-phenylcyclopropane-1-carboxylic acid which was converted
into methyl ester, and heating of the latter for 1 h in toluene gave methyl (E)-2-(2-phenylcyclopropylidene)-
acetate. Thermal isomerization of methyl (E)-2-(2-phenylcyclopropylidene)acetate on prolonged heating in
toluene afforded 5-methoxy-3-methyl-2-phenylfuran, and the reaction with 1,3-diphenyl-2-benzofuran resulted
in [4+2]-cycloaddition at the exocyclic double bond.
DOI: 10.1134/S1070428013040064
Compounds containing a three-membered ring with
endo- or exocyclic double bond are characterized by
a strain energy exceeding that typical of cyclopropane
derivatives by a factor of 1.5 to 2 [1]. A widely used
method of synthesis of methylidenecyclopropanes is
based on the reaction of carbenes with allenes. Di-
chloro- and dibromocarbenes selectively add at the
most substituted double bond of allenic hydrocarbons.
At elevated temperature dihalo(methylidene)cyclo-
propanes undergo rearrangement through trimethylene-
methyl diradical, which leads to substituted dihalo-
methylidenecyclopropanes as the major products [2].
The presence of an aryl group on the three-membered
ring facilitates the rearrangement, and in some cases
primary products of carbene reactions with phenyl-
substituted allenes could not be isolated [3]. Ethyl
diazoacetate and diethyl diazomalonate reacted with
1,1-disubstituted allenes in the presence of rhodium
compounds to give products of addition of the corre-
sponding carbene species at the least substituted
double bond [4]. The reaction of ethyl diazoacetate
with 1,1-dimethylallene, catalyzed by copper salts,
resulted in the formation of a complex mixture of
products [5]. On the other hand, copper-catalyzed reac-
tion of phenylallene with ethyl diazoacetate afforded
addition products to the C1=C2 bond [6].
In the present work we studied the reaction of
methyl diazoacetate with phenylallene (I) in the pres-
ence of dirhodium tetraacetate. From the complex mix-
ture of products we isolated by column chromatog-
raphy a mixture of three isomeric methylidenecyclo-
propanes II, trans-III, and cis-III at a ratio of 6:1:1 in
an overall yield of 30% (Scheme 1). Adducts trans-III
and cis-III polymerized on heating for 10 h in boiling
toluene, whereas compound II remained unchanged
under these conditions and was isolated as individual
substance.
Methylidenecyclopropane trans-III was synthe-
sized according to a different scheme starting from
cycloprop-2-enecarboxylic acid IV [7]. Isomerization
of IV by the action of potassium tert-butoxide gave
2-methylidenecyclopropanecarboxylic acid V (cf. [8])
Scheme 1.
CH2
CH2
N2CHC(O)OMe
Rh2(OAc)4, CH2Cl2
MeO
Ph
+
+
Ph
·
CH2
Ph
C(O)OMe
trans-III
Ph
C(O)OMe
cis-III
O
I
II
530

METHYL (E)-2-(2-PHENYLCYCLOPROPYLIDENE)ACETATE
531
Scheme 2.
CH2
C(O)OH
CH2
t-BuOK
Me2SO4
Ph
Me
Ph
C(O)OH
Ph
C(O)OMe
IV
V
trans-III
Scheme 3.
O
[O]
OMe
Ph
C(O)OMe
Me
VIII
O
Me
CH2
110°C
110°C
O
Ph
O
OMe
OMe
O
O
Ph
C(O)OMe
trans-III
Ph
N
O
VI
VII
C6H4Cl-4
Me Ph
N
O
C6H4Cl-4
IX
which was treated with dimethyl sulfate to obtain
methyl ester trans-III (Scheme 2). The formation of
S-benzylthiuronium salt of acid V by alkaline decom-
position of 3-bromo-4,6-dimethyl-5-phenylpyran-2-
one was described in [9].
Heating of trans-III in boiling toluene (110°C) for
1 h afforded methylidenecyclopropane VI containing
an impurity of furan VII (Scheme 3). The structure of
compounds VI and VII was determined by spectral
methods. When ester trans-III was heated in boiling
toluene for a longer time (5 h), furan VII was formed
as the only product which polymerized on prolonged
heating. Compound VII is readily oxidized to ketone
VIII [10]. The reaction of VII with N-(4-chloro-
phenyl)maleimide gave adduct IX (yield 72%) which
was assigned endo configuration on the basis of its
two-dimensional 1H–1H NOESY spectrum.
clopropene IV originates from methylenecyclopropane
VI; therefore, the thermal decomposition of VI was
carried out in the presence of 1,3-diphenyl-2-benzo-
furan (X) which is known to efficiently trap cyclo-
propenes [12]. However, heating of a mixture of
methylidenecyclopropane VI and isobenzofuran X in
toluene (3 h, 110°C) led to the formation of stereo-
isomeric adducts XIa and XIb (3:1) that are [4+2]-
cycloaddition products at the exocyclic double bond
(Scheme 4). No cycloadducts of X with cyclopropene
were detected. Diels–Alder adducts with methylidene-
cyclopropanes were reported previously only for the
reactions of (difluoromethylidene)cyclopropane with
furan and cyclopentadiene [13].
The structure of compounds XIa and XIb was
determined on the basis of their spectral parameters.
1
Their relative configuration was ascertained by H–1H
NOESY and X-ray analysis of XIa (see figure).
2-Ethoxyfurans were synthesized previously by
reaction of arylalkynes with ethyl diazoacetate in the
presence of copper salts or copper bronze [11]. It was
also found that furans are formed via thermal catalytic
isomerization of 2,3-disubstituted cycloprop-2-enecar-
boxylates. We initially presumed that in our case cy-
Presumably, the transformation of methylidenecy-
clopropane III into furan VII involves trimethylene-
methyl diradical XII which undergoes 1,5-cyclization
with participation of the terminal carbon and oxygen
atoms (Scheme 5). This mechanism is analogous to the
Scheme 4.
Ph
Ph
Ph
O
O
O
C(O)OMe
C(O)OMe
H
Toluene, 110°C
C(O)OMe
Ph
+
+
H
Ph
Ph
Ph
Ph
H
Ph
H
XIa
VI
X
XIb
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 4 2013

MOLCHANOV et al.
532
Scheme 5.
OMe
O
OMe
OMe
OMe
O
·
O
O
trans-III
·
Ph
Ph
·
·
H2C
H2C
H2C
Me
Ph
Ph
H
H
H
XII
VII
Scheme 6.
R
Cu+
R
*
R
R
R
Cu2+
–Cu+
*
*
O
O
EtO
R
H
H
O
OEt
XIV
EtO
XIII
scheme of thermal catalytic isomerization of substitut-
ed cycloprop-2-enecarboxylates into 2-alkoxyfurans. It
includes formation of copper(I) complex XIII via
coordination of the strained double bond, opening of
the three-membered ring to produce vinylcarbene
complex with copper(II), simultaneous one-electron
transfer from the copper atom and formation of penta-
dienyl anion XIV, 1,5-electrocyclization of the latter to
furan ring, back one-electron transfer to the copper
atom, and removal of copper(I) ion (Scheme 6).
The obtained results allowed us to conclude that
methoxycarbonylcarbene generated from methyl di-
azoacetate under catalysis by Rh2(OAc)4 adds to both
double bonds of phenylallene, preferably to the least
substituted one. Base-catalyzed isomerization of
3-methyl-2-phenylcycloprop-2-enecarboxylic acid
yields trans-2-methylidene-3-phenylcyclopropane-
carboxylic acid (V), and thermal isomerization of its
methyl ester trans-III affords methyl 2-(2-phenyl-
cyclopropylidene)acetate (VI); prolonged heating of
the latter gives 5-methoxy-3-methyl-2-phenylfuran
(VII). The mechanism of this unusual isomerization is
analogous to that of thermal catalytic isomerization of
substituted cycloprop-2-enecarboxylates into 2-alkoxy-
furans.
C31
C10
C30
C29
C32
C9
C8
O1
C27
C26
C11
C12
C28
O2
C13
C1
C2
O3
C14
C24
C7
EXPERIMENTAL
C3
C4
C25
C23
C6
C5
The elemental compositions were determined on
a Hewlett Packard 185-B CHN analyzer. The IR spec-
tra were recorded from 2% solutions in chloroform on
C15
C16
1
a UR-20 spectrometer. The H and 13C NMR spectra
C17
C22
were measured on a Bruker DPX-300 instrument at
300.13 and 75.47 MHz, respectively, using CDCl3 as
solvent. The mass spectra were obtained on a Bruker
microTOF mass spectrometer (electrospray ionization,
positive ion detection). The progress of reactions and
the purity of the isolated compounds were monitored
by TLC on Silufol UV-254 plates.
C18
C19
C21
C20
Structure of the molecule of methyl (2R)-1′,4′-epoxy-1′,4′,2-
triphenyl-3′,4′-dihydro-1′H-spiro[cyclopropane-1,2′-naph-
thalene]-3′-carboxylate (XIa) according to the X-ray diffrac-
tion data.
X-Ray analysis of compound XIa. Single crystals
of XIa were obtained by crystallization from methy-
lene chloride–ethanol. The X-ray diffraction data were
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 4 2013

METHYL (E)-2-(2-PHENYLCYCLOPROPYLIDENE)ACETATE
533
acquired on a Bruker APEX2 CCD diffractometer
(graphite monochromator, λCuKα = 1.54184 Å). Color-
less monoclinic crystals, C32H26O3, M 458.55; unit cell
parameters: a = 17.5766(2), b = 10.94018(13), c =
(1H, CH), 5.43 s (1H, OH), 5.78–5.81 m (2H, CH2),
7.19 d (2H, Harom, J = 8.0 Hz), 7.28–7.36 m (3H,
Harom). Crude acid V, 2.15 g (12 mmol), was dissolved
in 25 ml of methanol, 2.5 ml of dimethyl sulfate was
added, the mixture was stirred for 3 days at room tem-
perature and evaporated under reduced pressure, and
the residue was purified by column chromatography on
silica gel using hexane–diethyl ether as eluent. Yield of
trans-III 1.9 g (84%), colorless oily substance. IR
spectrum, ν, cm–1: 3060, 2956, 1724 s, 1600, 1496,
25.7386(3) Å; β = 90.0658(11)°; Z = 4, dcalc
=
1.231 g/cm3; V = 4949.30(10) Å3; space group P21/c
(no. 14). Number of reflections 7839; final divergence
factor R = 0.0489. The complete set of crystallographic
data for compound XIa was deposited to the Cam-
bridge Crystallographic Data Centre (entry no. CCDC
923530).
1
1438, 1328, 1100. H NMR spectrum, δ, ppm: 2.32–
2.35 m (1H, CH), 3.31–3.34 m (1H, CH), 3.76 s (3H,
Me), 5.76–5.78 m (2H, =CH2), 7.18–7.21 m (2H,
Harom), 7.25–7.31 m (3H, Harom). 13C NMR spectrum,
δC, ppm: 29.8 (CH), 29.9 (CH), 52.5 (CH3), 107.0
(CH2), 127.2 (CH), 127.4 (CH), 129.0 (CH), 134.2 (C),
138.7 (C), 171.7 (C=O). Found: m/z 189.0877
[M + H]+. C12H12O2. Calculated: [M + H] 189.0916.
Reaction of methyl diazoacetate with phenyl-
allene (I). A solution of 20 mmol of methyl diazo-
acetate in 10 ml of methylene chloride was added over
a period of 4 h to a mixture of 30 mmol of allene I and
30 mg of Rh2(OAc)4 in 10 ml of methylene chloride,
heated to 40°C. The mixture was stirred for 3 h,
cooled, and evaporated, and the residue was subjected
to chromatographic separation on silica gel using
petroleum ether (40–70°C)–ethyl acetate as eluent.
Methyl (E)-2-(2-phenylcyclopropylidene)acetate
(VI). A solution of 510 mg (2.7 mmol) of trans-III in
10 ml of anhydrous toluene was heated for 1 h at
110°C. The mixture was evaporated under reduced
pressure, and the residue was purified by column chro-
matography on silica gel using hexane–ethyl acetate
(6:1) as eluent. Yield 380 mg (75%), colorless oily
substance. IR spectrum, ν, cm–1: 3064, 2952, 1762,
Methyl (E)-2-benzylidenecyclopropanecarbox-
ylate (II). Yield 0.87 g (23%), oily substance. IR spec-
trum, ν, cm–1: 3064, 1724 s, 1600, 1492, 1440, 1363,
1
1334, 1276. H NMR spectrum, δ, ppm: 1.99 d.d.d
(1H, CH2, J = 9.5, 8.0, 2.2 Hz), 2.16 d.d.d (1H, CH2,
J = 9.5, 4.4, 2.2 Hz), 2.40 d.d.d (1H, CH, J = 8.0, 4.4,
2.2 Hz), 3.73 s (3H, Me), 6.85 q (1H, =CH, J =
1
1710 s, 1604, 1496, 1452, 1440, 1360, 1280. H NMR
2.2 Hz), 7.28 t (1H, Harom, J = 7.3 Hz), 7.37 (2H, Harom
,
spectrum, δ, ppm: 1.65 d.d.d (1H, CH2, J = 10.9, 6.5,
2.2 Hz), 2.13 t.d (1H, CH2, J = 10.9, 2.2 Hz),
2.79 d.d.d (1H, CH, J = 10.9, 6.5, 2.2 Hz), 3.82 s (3H,
J = 7.3 Hz), 7.54 d (2H, Harom, J = 7.3 Hz). 13C NMR
spectrum, δC, ppm: 13.2 (CH2), 16.3 (CH), 52.4 (CH3),
120.2 (CH), 123.3 (C), 127.5 (CH), 128.0 (CH), 129.0
(CH), 137.0 (C), 173.1 (C=O). Found: m/z 189.0896
[M + H]+. C12H12O2. Calculated: [M + H] 189.0916.
Me), 6.40 q (1H, =CH, J = 2.2 Hz), 7.14 d (2H, Harom
,
J = 8.0 Hz), 7.22 t (1H, Harom, J = 8.0 Hz), 7.30 t (2H,
Harom, J = 8.0 Hz). 13C NMR spectrum, δC, ppm: 15.9
(CH2), 19.7 (CH), 52.0 (CH3), 111.9 (CH), 126.9 (CH),
127.0 (CH), 129.0 (CH), 140.3 (C), 148.9 (C), 166.9
(C=O). Found: m/z 211.0667 [M + Na]+. C12H12O2.
Calculated: [M + Na] 211.0735.
Methyl cis-2-methylidene-3-phenylcyclopro-
1
panecarboxylate (cis-III). H NMR spectrum, δ, ppm
(from a mixture with II and trans-III): 2.79 d.t (1H,
CH, J = 9.4, 2.2 Hz), 3.33 d.t (1H, CH, J = 9.4,
2.2 Hz), 3.41 s (3H, Me), 5.83 t (1H, =CH, J = 2.2 Hz),
5.86 t (1H, =CH, J = 2.2 Hz), 7.18–7.35 m (5H, Harom).
5-Methoxy-3-methyl-2-phenylfuran (VII). A so-
lution of 600 mg of trans-III in 10 ml of toluene was
heated for 10 h at 110°C (or ester VI was heated in
toluene for 5 h). The solvent was evaporated under
reduced pressure, and the residue was purified on
a column charged with silica gel using hexane–ethyl
acetate (6:1) as eluent. Yield 435 mg (73%), colorless
oily substance. 1H NMR spectrum, δ, ppm: 2.27 s (3H,
Me), 3.89 s (3H, OMe), 5.16 s (1H, CH), 7.20 t (1H,
Methyl trans-2-methylidene-3-phenylcyclopro-
panecarboxylate (trans-III). Potassium tert-butoxide,
4.4 g (30 mmol), was added to a solution of 2.2 g
(13 mmol) of acid IV in 30 ml of anhydrous tert-butyl
alcohol. The mixture was stirred for 3 days at room
temperature and evaporated under reduced pressure,
the residue was treated with 50 ml of water, acidified
with hydrochloric acid, and extracted with methylene
chloride, and the extract was dried over MgSO4 and
H
arom, J = 8.0 Hz), 7.39 t (2H, Harom, J = 8.0 Hz),
7.55 d (2H, Harom, J = 8.0 Hz). 13C NMR spectrum, δC,
ppm: 12.8 (CH3), 58.0 (OCH3), 85.6 (CH), 118.5 (C),
124.8 (CH), 126.0 (CH), 128.8 (CH), 132.2 (C), 139.4
1
evaporated. Yield of acid V 2.15 g (98%). H NMR
spectrum, δ, ppm: 2.30–2.33 m (1H, CH), 3.35–3.38 m
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 4 2013

MOLCHANOV et al.
534
(C), 160.7 (C). Found: m/z 211.0717 [M + Na]+.
C12H12O2. Calculated: [M + Na] 211.0735.
3′-carboxylate (XIa). Yield 165 mg (72%, major
isomer), white powder, mp 183–185°C. IR spectrum,
ν, cm–1: 3064, 3028, 2948, 1747 s, 1719, 1610, 1495,
Methyl (2E)-3-methyl-4-oxo-4-phenylbut-2-
enoate (VIII). Compound VII was kept for 10 days at
room temperature on exposure to air. Yield of VIII
quantitative, white powder, mp 46–47°C. IR spectrum,
ν, cm–1: 3060, 2950, 1716 s, 1674 s, 1644, 1600, 1452,
1
1448, 1433, 1350, 1305, 1263, 1192, 1149. H NMR
spectrum, δ, ppm: 1.06–1.12 m (2H, 3-H), 2.19 d.d
(1H, 2-H, J = 8.7, 8.0 Hz), 2.64 s (1H, 3′-H), 3.35 s
(3H, Me), 6.43–6.46 m (2H, Harom), 7.08–7.16 m (4H,
1
H
arom), 7.23 d.d (1H, Harom, J = 7.3, 6.5 Hz), 7.34–
1442, 1356, 1270, 1132. H NMR spectrum, δ, ppm:
7.49 m (5H, Harom), 7.53–7.62 m (4H, Harom), 7.71 d
(1H, Harom, J = 7.3 Hz), 7.94 d (2H, Harom, J = 7.3 Hz).
13C NMR spectrum, δC, ppm: 15.0 (CH2), 26.0 (CH),
43.8 (C), 51.7 (CH), 54.9 (CH3), 89.8 (C), 90.0 (C),
119.1 (CH), 120.2 (CH), 126.2 (CH), 126.3 (CH),
126.7 (CH), 127.3 (CH), 127.6 (CH), 128.0 (CH),
128.1 (CH), 128.5 (CH), 128.6 (CH), 128.7 (CH),
129.0 (CH), 135.9 (C), 137.1 (C), 138.0 (C), 147.8 (C),
147.9 (C), 172.7 (C=O). Found, %: C 83.91; H 5.78.
C32H26O3. Calculated, %: C 83.82; H 5.72.
2.15 d (3H, Me, J = 1.5 Hz), 3.54 s (3H, OMe), 6.00–
6.12 m (1H, =CH), 7.48 t (2H, Harom, J = 8.0 Hz), 7.58
(1H, Harom, J = 8.0 Hz), 7.91 d (2H, Harom, J = 8.0 Hz).
13C NMR spectrum, δC, ppm: 22.1 (CH3), 52.0
(OCH3), 119.4 (CH), 129.0 (CH), 129.2 (CH), 134.0
(CH), 134.8 (C), 155.9 (C), 165.6 (C=O), 198.6
(C=O). Found: m/z 227.0658 [M + Na]+. C12H12O3.
Calculated: [M + Na] 227.0684.
2-(4-Chlorophenyl)-4,7-epoxy-7-methoxy-
5-methyl-4-phenyl-1H-3a,4,7,7-tetrahydroisoindole
(IX). A solution of 215 mg of methylidenecyclo-
propane VI and 208 mg of N-(4-chlorophenyl)male-
imide in 10 ml of toluene was heated for 9 h at 110°C
and was then evaporated under reduced pressure. Yield
285 mg (72%), white powder, mp 130–132°C (from
EtOH). IR spectrum, ν, cm–1: 3056, 2944, 1780, 1718 s,
1638, 1604, 1494, 1448, 1376, 1348, 1308, 1256,
Methyl (2S)-1′,4′-epoxy-1′,4′,2-triphenyl-3′,4′-di-
hydro-1′H-spiro[cyclopropane-1,2′-naphthalene]-
3′-carboxylate (XIb). Yield 55 mg (24%, minor
isomer), white powder, mp 124–126°C. IR spectrum,
ν, cm–1: 3056, 2947, 1740, 1721 s, 1601, 1497, 1448,
1
1348, 1306, 1263, 1181, 1066. H NMR spectrum, δ,
ppm: 1.20 d.d (1H, 3-H, J = 7.3, 6.5 Hz), 1.33 d.d (1H,
3-H, J = 8.7, 6.5 Hz), 1.92 d.d (1H, 2-H, J = 8.7,
7.3 Hz), 3.37 s (1H, 3′-H), 3.46 s (3H, Me), 6.97 d
(2H, Harom, J = 7.3 Hz), 7.10 d (1H, Harom, J = 7.3 Hz),
7.16–7.28 (4H, Harom), 7.32 t (1H, Harom, J = 7.3 Hz),
7.43–7.48 m (4H, Harom), 7.54–7.59 m (3H, Harom),
7.66 d (2H, Harom, J = 8.7 Hz), 7.78 (2H, Harom, J =
8.0 Hz). 13C NMR spectrum (CDCl3), δC, ppm: 11.5
(CH2), 26.5 (CH), 43.6 (C), 51.7 (CH), 53.5 (CH3),
90.6 (C), 90.8 (C), 119.3 (CH), 122.6 (CH), 125.4
(CH), 126.7 (CH), 126.8 (CH), 127.4 (CH), 127.6
(CH), 128.4 (CH), 128.6 (CH), 128.7 (CH), 128.8
(CH), 128.9 (CH), 129.1 (CH), 136.3 (C), 137.6 (C),
138.5 (C), 146.8 (C), 146.9 (C), 171.9 (C=O).
Found, %: C 83.86; H 5.78. C32H26O3. Calculated %:
C 83.82; H 5.72.
1
1124. H NMR spectrum, δ, ppm: 1.64 s (3H, Me),
3.73 s (3H, OMe), 3.77 d (1H, CH, J = 8.0 Hz), 4.03 d
(1H, CH, J = 8.0 Hz), 6.24 d (1H, =CH, J = 1.5 Hz),
7.14 d (2H, Harom, J = 8.7 Hz), 7.43–7.51 m (5H,
13
H
arom), 7.85 d (2H, Harom, J = 8.7 Hz). C NMR spec-
trum, δC, ppm: 14.5 (CH3), 52.3 (CH), 53.7 (CH), 55.1
(OCH3), 89.0 (C), 113.4 (C), 126.5 (CH), 127.4 (CH),
128.0 (CH), 128.9 (CH), 129.1 (CH), 129.9 (CH),
130.4 (C), 135.0 (C), 136.2 (C), 151.5 (C), 173.2
(C=O), 173.6 (C=O). Found, %: C 66.68; H 4.49;
N 3.51. C22H18ClNO4. Calculated, %: C 66.75; H 4.58;
N 3.54.
Methyl 1′,4′-epoxy-1′,4′,2-triphenyl-3′,4′-dihy-
dro-1′H-spiro[cyclopropane-1,2′-naphthalene]-
3′-carboxylates XIa and XIb. A solution of 113 mg
(0.6 mmol) of methylidenecyclopropane VI and
135 mg (0.5 mmol) of 1,3-diphenyl-2-benzofuran in
10 ml of toluene was heated for 3 h at 110°C. The
mixture was evaporated under reduced pressure, and
stereoisomers XIa and XIb were separated by crys-
tallization from ethanol. Compound XIa precipitated
first, and its recrystallization from a mixture of meth-
ylene chloride with ethanol gave crystals suitable for
X-ray analysis.
The X-ray analysis of compound XIa was
performed at the Research Center for X-ray Diffraction
Studies of the St. Petersburg State University.
This study was performed under financial support
by the Russian Foundation for Basic Research (project
no. 12-03-01008-a).
REFERENCES
Methyl (2R)-1′,4′-epoxy-1′,4′,2-triphenyl-3′,4′-
dihydro-1′H-spiro[cyclopropane-1,2′-naphthalene]-
1. Binger, P. and Büch, H.M., Top. Curr. Chem., 1987,
vol. 135, p. 77; Goti, A., Cordero, F.M., and Brandi, A.,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 4 2013

METHYL (E)-2-(2-PHENYLCYCLOPROPYLIDENE)ACETATE
535
Top. Curr. Chem., 1996, vol. 178, p. 1; Binger, P. and
Schmidt, T., Meth. Org. Chem. (Houben-Weyl), vol. E17c,
p. 2217; Brandi, A. and Goti, A., Chem. Rev., 1998,
vol. 98, p. 589; Brandi, A., Cicchi, C., Cordero, F.M., and
Goti, A., Chem. Rev., 2003, vol. 103, p. 1213; Audran, G.
and Pellisier, H., Adv. Synth. Catal., 2010, vol. 352,
p. 575; Pellisier, H., Tetrahedron, 2010, vol. 66, p. 8341.
6. Molchanov, A.P., Noskova, O.V., and Kostikov, R.R.,
Zh. Org. Khim., 1983, vol. 19, p. 1981.
7. Domnin, I.N., Zhuravleva, E.F., and Pronina, N.V.,
Zh. Org. Khim., 1978, vol. 14, p. 2323.
8. Ampilogova, N.A., D’yakonov, I.A., and Kosti-
kov, R.R., Zh. Org. Khim., 1966, vol. 2, p. 1898.
9. Gilchrist, T.L. and Rees, C.W., J. Chem. Soc. C, 1968,
2. Greibrokk, T., Acta Chem. Scand., 1973, vol. 27, p. 3207;
Rahman, W. and Kuivila, H.G., J. Org. Chem., 1966,
vol. 31, p. 772; Kostikov, R.R., Nagi, Sh.M., and Molcha-
nov, A.P., Zh. Org. Khim., 1983, vol. 19, p. 1437; Mol-
chanov, A.P. and Kostikov, R.R., Zh. Org. Khim., 1988,
vol. 24, p. 949.
3. Kostikov, R.R. and Ioffe, A.I., Zh. Org. Khim., 1970,
vol. 6, p. 2630; Kostikov, R.R., Vorob’eva, I.S., and Mol-
chanov, A.P., Zh. Org. Khim., 1983, vol. 19, p. 256;
Kostikov, R.R. and Molchanov, A.P., Dokl. Akad. Nauk
SSSR, 1979, vol. 246, p. 1377.
p. 769.
10. Bonete, P. and Nájera, C., J. Org. Chem., 1994, vol. 59,
p. 3202.
11. D’yakonov, I.A. and Komendantov, M.I., Zh. Obshch.
Khim., 1963, vol. 33, p. 2448; D’yakonov, I.A., Komen-
dantov, M.I., and Smirnova, T.S., Zh. Org. Khim., 1969,
vol. 5, p. 1742; Zhou, L., Ma, J., Zhang, Y., and
Wang, J., Tetrahedron Lett., 2011, vol. 52, p. 5484;
Briones, J.F. and Davies, H.M.L., Tetrahedron, 2011,
vol. 67, p. 4313.
12. Wiberg, K. and Bonneville, G., Tetrahedron Lett., 1982,
vol. 23, p. 5385; Chenier, P.J. and Southard, D.A., Jr.,
J. Org. Chem., 1990, vol. 55, p. 4333.
4. Huval, C.C. and Singleton, D.A., J. Org. Chem., 1994,
vol. 59, p. 2020; Singleton, D.A., Huval, C.C.,
Church, K.M., and Priestley, E.S., Tetrahedron Lett.,
1991, vol. 32, p. 5765.
13. Hang, X-C., Chen, Q-Y.; and Xiao, J-C., Eur. J. Org.
Chem., 2008, p. 1101.
5. Creary, X., J. Org. Chem., 1978, vol. 43, p. 1777.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 49 No. 4 2013