Synthesis and chemical transformations of 2-cyclopropyl-2-diazoacetates

Article abstract of DOI:10.1007/s11172-007-0234-6

Methyl 2-cyclopropyl-2-diazoacetate was synthesized from acetylcyclopropane in few chemical steps in ～55% total yield. Its copper or rhodium-catalyzed dediazoniation exclusively proceeds through the intramolecular isomerization of generated cyclopropyl(methoxycarbonyl)carbene to 1-methoxycarbonylcyclobutene, irrespective of the presence or the absence of unsaturated compounds. However, in the presence of acrylates or strained cycloalkenes, this diazo ester is being slowly involved into the 1,3-dipolar cycloaddition, giving cyclopropyl- substituted pyrazolinecarboxylates, which in case of 1-pyrazolines easily lose nitrogen molecule to selectively afford 1-cyclopropylcyclopropanecarboxylate derivatives.

Full text of DOI:10.1007/s11172-007-0234-6

Russian Chemical Bulletin, International Edition, Vol. 56, No. 8, pp. 1515—1521, August, 2007
1515
Synthesis and chemical transformations
of 2ꢀcyclopropylꢀ2ꢀdiazoacetates*
V. V. Prokopenko, G. P. Okonnishnikova, I. P. Klimenko, E. V. Shulishov, and Yu. V. Tomilovꢀ
N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences,
47 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 6390. Eꢀmail: tom@ioc.ac.ru
Methyl 2ꢀcyclopropylꢀ2ꢀdiazoacetate was synthesized from acetylcyclopropane in few
chemical steps in ~55% total yield. Its copper or rhodiumꢀcatalyzed dediazoniation exclusively
proceeds through the intramolecular isomerization of generated cyclopropyl(methoxyꢀ
carbonyl)carbene to 1ꢀmethoxycarbonylcyclobutene, irrespective of the presence or the abꢀ
sence of unsaturated compounds. However, in the presence of acrylates or strained cycloalkenes,
this diazo ester is being slowly involved into the 1,3ꢀdipolar cycloaddition, giving cyclopropylꢀ
substituted pyrazolinecarboxylates, which in case of 1ꢀpyrazolines easily lose nitrogen molꢀ
ecule to selectively afford 1ꢀcyclopropylcyclopropanecarboxylate derivatives.
Key words: diazo esters, cyclopropylcarbene—cyclobutene isomerization, 1,3ꢀcycloaddiꢀ
tion, pyrazolinecarboxylates, dediazoniation, dicyclopropyls, cyclopropanes.
Diazo carbonyl compounds are valuable synthons for
the fine organic synthesis and are widely used in the reacꢀ
tions, proceeding either with retention (mainly 1,3ꢀdipoꢀ
lar cycloaddition reactions) or with elimination of nitroꢀ
gen molecule.1—3 In the latter case, the dediazoniation,
assisted by the metal complex catalysts or by the Lewis
acids, is the most efficient one. In particular, the catalytic
dediazoniation of diazo compounds serves as a conveꢀ
nient method for the cyclopropanation of various unsatꢀ
urated compounds or for the formation of the insertion
products of the corresponding carbenes into С—Н or
С—heteroatom bonds.3—5
teristic of 2ꢀdiazoalkanecarboxylic acid esters, dediꢀ
azoniation of which shows that the main competing with
the interception of the corresponding carbenes process
consists in the isomerization of the latter into alkeneꢀ
carboxylates.6,8
In the present work, we elaborated a convenient
method for the synthesis of 2ꢀcyclopropylꢀ2ꢀdiazoacetic
acid esters (1) from available acetylcyclopropane and
studied some of their chemical transformations, in parꢀ
ticular, 1,3ꢀdipolar cycloaddition of methyl 2ꢀcycloꢀ
propylꢀ2ꢀdiazoacetate (1a) to acrylates and strained
cycloalkenes was investigated for the first time.
2ꢀCyclopropylꢀ2ꢀdiazoacetic acid esters can be of inꢀ
terest as the synthons for the preparation of cyclopropylꢀ
substituted nitrogenꢀcontaining heterocycles or dicycloꢀ
propyl derivatives with various combinations of substituꢀ
ents in the small rings. However, in contrast to the most
widely used diazoacetates and other diazo carbonyl comꢀ
pounds, capable of metalꢀcatalyzed generating of the corꢀ
responding carbene intermediates, which further react in
the [1+2]ꢀcycloaddition or insertion into C—Y bonds with
the suitable substrates, αꢀcyclopropylꢀsubstituted diazo
esters are less available, bear some specific properties, and
are virtually not investigated for the synthetic purposes.
To a certain extent, it can be attributed both to their low
stability and to the ability of easy forming cyclopropylꢀ
carbenes to undergo isomerization to the corresponding
cyclobutenes.6,7 The similar transformations are characꢀ
Results and discussion
2ꢀCyclopropylꢀ2ꢀdiazoacetic acid ester 1 can be preꢀ
pared by decomposition of tosylhydrazones of the correꢀ
sponding cyclopropylꢀsubstituted αꢀketoesters.7 To obꢀ
tain diazo esters devoid of substituents in cyclopropane
ring, one can start from acetylcyclopropane (2) by its
prior oxidation to αꢀketo acid 3 (Scheme 1). However,
the described in the literature9 method for the preparation
of keto acid 3 by potassium permanganate oxidation of
ketone 2 in the presence of Na2CO3 requires a prolong
heating and slow addition of the oxidant (36 h at 50 °С).
By changing of the order of addition of reagents (see
Experimental) and by the use of КОН solution as the
base, we were able to decrease the reaction time to 1 h and
to increase the yield of ketoacid to 75%. Further methylaꢀ
tion of the acid obtained with diazomethane and converꢀ
* Dedicated to Academician V. A. Tartakovsky in honor of his
75th anniversary.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1459—1465, August, 2007.
1066ꢀ5285/07/5608ꢀ1515 © 2007 Springer Science+Business Media, Inc.

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Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
Prokopenko et al.
sion of keto ester 4 to tosylhydrazone 5 were carried out
by the usual procedures (see Scheme 1). There is inforꢀ
mation on the synthesis of methyl 2ꢀcyclopropylꢀ2ꢀdiazoꢀ
acetate (1a) and its photolytic cleavage, though, neither
the reaction conditions nor the yield of diazo compound
1a were reported.6 The later work7 described the synthesis
of methyl esters of cisꢀ and transꢀ2ꢀdiazoꢀ2ꢀ(2,3ꢀdiꢀ
methylcyclopropyl)acetic acid in ~38% yield, where
MeONa in pyridine was used for the decomposition of
the corresponding tosylhydrazones of αꢀketo esters. It
can be assumed that the same procedure was applied
for the synthesis of unsubstituted in the cyclopropane
ring diazo ester 1a. We changed the reaction conditions
and found that the decomposition of tosylhydrazone 5
in acetonitrile assisted by triethylamine at 7 °С allows one
to obtain diazo ester 1a in up to 78% isolated yield
(see Scheme 1). Similarly to the case of its dimethyl
analog,7 the obtained diazo ester contained 3—5% of
methyl cyclobutꢀ1ꢀenecarboxylate (6a) as a byꢀproduct,
which was formed by the partial dediazoniation of diazo
ester 1a and the intramolecular isomerization of cycloproꢀ
pyl(methoxycarbonyl)carbene.
propylcarbene—cyclobutene isomerization, we syntheꢀ
sized allyl ester of 2ꢀcyclopropylꢀ2ꢀdiazoacetic acid (1b),
applying procedure for the esterification of cyclopropaneꢀ
carboxylic acids10 with allyl alcohol and subsequent reacꢀ
tions similar to those used in the preparation of diazo
ester 1a. However, it turned out that the catalytic decomꢀ
position of obtained diazo ester 1b in the presence of
(PhO)3P·CuCl or Rh2(OAc)4 did not lead to a noticeable
formation of the bicyclic lactone, rather allyl cyclobutꢀ1ꢀ
enecarboxylate (6b) was the main product of the deꢀ
diazoniation of 1b (Scheme 2). Thus, if the photolysis
(first of all, photosensitization) of αꢀcyclopropyldiazoꢀ
acetates in the presence of olefins leads to a certain extent
of intermolecular interception of forming cyclopropylꢀ
carbenes,6,7 then the catalytic dediazoniation of αꢀcycloꢀ
propylꢀsubstituted diazo esters, apparently, leaves not
much hope of successful interception of carbenes with the
other substrates.
Scheme 2
Scheme 1
In contrast to inefficient catalytic cyclopropanation of
olefins with cyclopropylꢀcontaining diazo ester 1a, its
1,3ꢀdipolar cycloaddition reactions to unsaturated comꢀ
pounds, containing electronꢀwithdrawing substituents or
strained double bonds, proceed quite successfully. Thus
the reaction of diazo ester 1a with methyl acrylate or
acrylonitrile leads to the corresponding functionally subꢀ
stituted 5ꢀcyclopropylꢀ2ꢀpyrazolines 7 and 8, which
were isolated by vacuum distillation in 60—65% yield
(Scheme 3).
Reagents and conditions: i. KMnO4, KOH, 60 °C, 1 h; ii. Dowex
50WX8ꢀ100 (H+) resin; iii. CH2N2 in ether; iv. H2NNHTs,
MeOH; v. Et3N, MeCN, 5—7 °C; vi. Rh2(OAc)4, CH2Cl2, 20 °C
or (PhO)3P·CuCl, CH2Cl2, 40 °C.
The carbene decomposition of diazo ester 1a, cataꢀ
lyzed by the transition metal complexes, in particular
(PhO)3P·CuCl and Rh2(OAc)4, proceeds quite effiꢀ
ciently to give exclusively cyclobutenecarboxylate 6a (see
Scheme 1). Addition of various unsaturated compounds
(cyclohexene, norbornene, and ethyl vinyl ether) into the
reaction mixture does not lead to a noticeable formation
of the corresponding products of cyclopropanation, alꢀ
ways leaving cyclobutene 6a virtually the only product.
It is known, for example (see Ref. 5), that the catalytic
decomposition of allyl esters of αꢀdiazocarboxylic acids
leads to the products of intramolecular cyclopropanation,
viz., to the corresponding 3ꢀoxabicyclo[3.1.0]hexanꢀ2ꢀ
ones, in good yields. In order to investigate the competing
processes of intramolecular cyclopropanation and cycloꢀ
Scheme 3
7: R = CO2Me (65%)
8: R = CN (60%)
Conditions: 7—10 °C, 7 days.

2ꢀCyclopropylꢀ2ꢀdiazoacetic esters
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
1517
The solventꢀfree storage of diazo ester 1a with methyl
methacrylate at 7—10 °С for 15 days leads to the formaꢀ
tion of isomeric cisꢀ and transꢀ1ꢀpyrazolines 9 in the ratio
~1 : 2.2 (Scheme 4). In contrast to 2ꢀpyrazolines 7 and 8,
the obtained pyrazolines 9 easily decompose with evoluꢀ
tion of nitrogen even under mild heating. Thus they comꢀ
pletely are converted to the corresponding 1ꢀcycloꢀ
propylcyclopropaneꢀ1,2ꢀdicarboxylates 10 for 1 h at 50 °С,
retaining the ratio of cisꢀ and transꢀisomers close to that
in the starting pyrazolines. The assignment of isomers was
made based upon 1Н NMR spectroscopic data on the
difference between chemical shifts of geminal protons in
tetrasubstituted cyclopropane ring, which is much higher
for cisꢀisomers 9 and 10 (∆δ 1.42 and 1.07, respectively)
in comparison with the corresponding transꢀisomers
(∆δ 0.11 and 0.16). These regularities are also characterisꢀ
tic of the other close structures, containing cycloproꢀ
paneꢀ1,2ꢀdicarboxylic acid fragment.11 Cyclopropanediꢀ
carboxylates 10 obtained upon treatment with KOH in
methanol, followed by acidification of the potassium
salt, can be transformed to the corresponding cisꢀ and
transꢀcyclopropanedicarboxylic acids 11 with retention of
both cyclopropane fragments in the molecule.
butenecarboxylate 6a, which, when the other interceptors
of diazo esters 1 are used, can be a side process. Thus
keeping of a mixture of diazo ester 1a with the twoꢀfold
excess of cyclobutene 6a at 5—7 °С for 14 days gives
stereoisomeric bicyclic pyrazolines 12 in 35—38% yield
with the ratio of antiꢀ and synꢀisomers being ~1 : 4.2
(Scheme 5).
Scheme 5
Scheme 4
Reagents and conditions: i. 7—10 °C, 14 days, solventꢀfree;
ii. 1000 MPa, 10 °С, 24 h; iii. С6Н6, 80 °С, 1.5 h.
The effectivity of 1,3ꢀdipolar cycloaddition of diazo
ester 1a to cyclobutene 6a and, correspondingly, the yield
of pyrazolines 12 are significantly higher (up to 75%),
when the reaction is carried out under high pressure
(1000 MPa, 10 °С, 24 h). Separation of the reaction mixꢀ
ture by preparative TLC on SiO2 allowed us to isolate a
pure synꢀisomer 12 and to obtain an enriched with
antiꢀisomer fraction (~80%). Similarly to the formation
of pyrazolines 9, we assumed that isomer with transꢀarꢀ
rangement of two ester substituents should be predomiꢀ
nant in this reaction. In addition, the formation of
antiꢀisomer 12 seems to be sterically less probable due to
the strong overlap of Н(6) proton and protons in the
cyclopropyl substituent.
The dediazoniation of pyrazolines 12 in benzene at
80 °С gives 5ꢀcyclopropylꢀ1,5ꢀdi(methoxycarbonyl)biꢀ
cyclo[2.1.0]pentanes 13 in high yields, moreover, the inꢀ
dividual synꢀisomer 12 exclusively gives rise to synꢀisoꢀ
mer 13. The absence of isomeric unsaturated comꢀ
pounds (or at least their very low content) among reacꢀ
tion products makes it different from the dediazoniation
of other such pyrazolines, for example, 2,3ꢀdiazabiꢀ
cyclo[3.2.0]heptꢀ2ꢀenes12 or similar pyrazolines, formed
by addition of diazo compounds, in particular, ethyl
Reagents and conditions: i. 7—10 °C, 14 days, solventꢀfree;
ii. CHCl3, 50 °С, 1 h; iii. KOH/MeOH, 60 °С, 2 h, then
1 M HCl.
It turned out that diazo ester 1a can slowly react with
the product of its own dediazoniation, i.e., with cycloꢀ

1518
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
Prokopenko et al.
diazoacetate, to 1ꢀmethoxycarbonylchlorotrifluorocycloꢀ
butene.13
cyclobutene. However, the reactions of 1,3ꢀdipolar cyꢀ
cloaddition with the formation of cyclopropylꢀsubstituted
pyrazolinecarboxylates can be implemented for it. The
latter, in case of 1ꢀpyrazolines, containing electronꢀwithꢀ
drawing substituents, easily lose nitrogen molecule to be
selectively converted to the derivatives of 1ꢀcyclopropylꢀ
cyclopropanecarboxylates.
1,3ꢀDipolar cycloaddition of diazo ester 1a to norꢀ
bornene at 7—10 °С proceeds also slow enough and, due
to the side reactions, leads to a mixture of compounds,
from which isomeric tricyclic pyrazolines 14 were isoꢀ
lated by column chromatography on SiO2 in 40—45%
yield and in ~1 : 2.5 ratio of antiꢀ and synꢀisomers
(Scheme 6). A decrease of the reaction time by an inꢀ
crease in the temperature (50 °С, 4 days) decreases the
yield of the target product to 30%. At the same time,
conducting of the reaction under high pressure (1000 MPa,
15 °С, 48 h) not only accelerates the reaction, but also
considerably increases the total yield of pyrazolines
antiꢀ and synꢀ14 (to 75%).
Experimental
1
Н and 13С spectra were recorded on a Bruker ACꢀ200 (200
and 50.3 MHz), Bruker AMꢀ300 (300 and 75.5 MHz), and
Bruker DRXꢀ500 (500 and 125.3 MHz, respectively) spectromꢀ
eters in CDCl3 solutions, containing 0.05% of Me4Si as the
internal standard; the COSY, NOESY, and HSQC experiments
were performed on a Bruker DRXꢀ500 spectrometer. Mass specꢀ
tra were recorded on a Finnigan MAT INCOSꢀ50 (EI, 70 eV,
direct injection) and Finnigan LCQ (electroꢀspray ionization
(ESI)) instruments for MeCN solutions. Elemental analysis data
were obtained on a PerkinElmer Series II, 2400 C,H,Nꢀanaꢀ
lyzer. Thin layer chromatography was performed on silica gel 60
(Merck) plates with visualization in iodine chamber. Column
chromatography was used for the preparative isolations (silica
gel 60, 0.040—0.063 mm, Merck) with the substance—absorꢀ
bent ratio being ~1 : 60. Acetylcyclopropane (99% purity) was
synthesized according to the described procedure.14 Chemically
pure solvents (>99.6%) were used in this work without addiꢀ
tional purification.
Scheme 6
2ꢀCyclopropylꢀ2ꢀoxoacetic acid (3). Acetylcyclopropane (2)
(12.6 g, 0.15 mol) was added to a solution of KMnO4 (44.2 g,
0.28 mol) in water (380 mL) with stirring, the mixture was
heated to 30 °С and 10% aq. KOH (6 mL) was added to this,
resulting in warming up of the reaction mixture to 60 °С, this
temperature was further kept for 1 h. After the reaction was
over, the mixture was filtered, the filtrate was concentrated, and
the formed potassium salt was converted to the acid according to
the described procedure9 with the use of Dowex 50WX8ꢀ100 (H+)
ionꢀexchange resin. Acid 3 (12.9 g, 75%) was obtained, b.p.
96—98 °C (18 Torr). MS (EI), m/z (Irel (%)): 114 (2) [М]+, 69
(97) [М – Н2О – СО]+, 41 (100). 1H NMR (CDCl3), δ: 1.32
Conditions: 7—10 °C, 14 days or 1000 MPa, 15 °С, 36 h.
Polycyclic pyrazolines 14 were isolated as the indiꢀ
vidual compounds by column chromatography on SiO2
with toluene—ethyl acetate (25 : 1) mixture as the eluent,
with the minor antiꢀisomer being the least strongly held
by the absorbent.
The structures of pyrazolines obtained were established
based on 1Н and 13С NMR spectra, mass spectra, and
elemental analysis data. The assignment of tricyclic strucꢀ
ture in both isomers to exoꢀconfiguration was made based
on the low values of spinꢀspin coupling constant for viciꢀ
nal protons Н(1)—Н(2) and on the presence of Wꢀconꢀ
stant for the remote protons На(10)—Нendo(2). The posiꢀ
tions of substituents at С(5) were established by the presꢀ
ence of the nuclear Overhauser effect between protons of
the cyclopropane ring and Н(6) proton in major isomer
and Hs(10) proton in minor one.
(m, 4 Н, СН2СН2); 2.93 (tt, 1 Н, СН, Jcis = 7.4 Hz, Jtrans
=
5.0 Hz); 9.11 (br.s, ОН). 13С NMR (CDCl3), δ: 15.31
(СН2СН2); 17.20 (СН); 160.91 (СОО); 195.86 (СО).
Methyl 2ꢀcyclopropylꢀ2ꢀoxoacetate (4). A solution of diazoꢀ
methane in ether (0.7 М, 93 mL, ~0.065 mol) was added to a
stirred solution of keto acid 3 (6.84 g, 0.06 mol) in ether at 10 °С.
After ether was evaporated and the residue was distilled in vacuo,
keto ester 4 (7.29 g, 95%) was obtained, b.p. 94—96 °С (35 Torr);
cf. Ref. 9: b.p. 85—90 °С (12 Torr). 1H NMR (CDCl3), δ:
1.21 (m, 4 Н, СН2СН2); 2.75 (tt, 1 Н, СН, Jcis = 7.7 Hz,
Jtrans = 4.7 Hz); 3.89 (s, 3 Н, OMe). 13С NMR (CDCl3), δ:
13.71 (CH2CH2); 18.28 (СН); 52.82 (OMe); 161.91 (COO);
194.0 (СO).
Tosylhydrazone of methyl 2ꢀcyclopropylꢀ2ꢀoxoacetate (5).
A solution of keto ester 4 (16.64 g, 0.13 mol) in methanol (12 mL)
was added dropwise to a solution of tosylhydrazine (24.18 g,
0.13 mol) in methanol (25 mL) at 30 °C and the reaction mixꢀ
ture was stirred at 50 °С for 6 h. After cooling, the formed
crystals were filtered off and dried in vacuo to give tosylhydrꢀ
In conclusion, methyl 2ꢀcyclopropyldiazoacetate
turned out to be inefficient in the direct catalytic cycloꢀ
propanation of unsaturated compounds due to the easy
intramolecular isomerization of intermediate cycloꢀ
propyl(methoxycarbonyl)carbene to 1ꢀmethoxycarbonylꢀ

2ꢀCyclopropylꢀ2ꢀdiazoacetic esters
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
1519
azone 5 (37.73 g, 98%), m.p. 68—69 °C. MS (EI), m/z (Irel (%)):
296 (25) [M]+, 237 (10) [M – CO2Me]+, 141 (70), 53 (100).
1H NMR (CDCl3), δ: 0.76 (m, 4 Н, СН2СН2); 1.92 (m, 1 Н,
СН); 2.42 (s, 3 Н, Me); 3.83 (s, 3 H, OMe); 7.30, 7.78 (both d,
2 Н each, C6H4, J = 7.7 Hz); 11.51 (br.s, 1 Н, NH). 13С NMR
(CDCl3), δ: 8.40 (СН2СН2); 12.47 (СН); 21.62 (Me); 52.64
(ОMe); 127.78 (mꢀС); 129.60 (oꢀС); 135.49 (pꢀС); 139.88
(ipsoꢀС); 144.20 (С=N); 162.47 (COO).
Methyl 2ꢀcyclopropylꢀ2ꢀdiazoacetate (1a). Triethylamine
(15 mL, 0.12 mol) was added to a stirred solution of tosylꢀ
hydrazone 5 (11.82 g, 0.04 mol) in acetonitrile (25 mL) and this
was stirred for 5 h at 5—7 °С. Then iceꢀcold water (400 mL) was
added and the mixture was extracted with ether (75 mL), the
organic layer was separated, dried with anhydrous Na2SO4, and
the solvent was evaporated. The residue was reꢀdistilled in vacuo
(10–2 Torr) into a trap cooled with dry ice. Diazo ester 1a
(4.55 g, 78%) was obtained as bright yellow liquid, containing
~4% methyl cyclobutꢀ1ꢀenecarboxylate (6a). 1H NMR (CDCl3),
Jcis = 10.4 Hz, J ≈ 1.5 Hz); 5.33 (dq, 1 Н, =CHb, Jtrans =
17.1 Hz, J ≈ 1.5 Hz); 5.94 (ddt, 1 Н, =СН, Jcis = 10.4 Hz,
Jtrans = 17.1 Hz, 3J = 5.5 Hz); 6.80 (t, 1 Н, Н(2), J = 1.2 Hz).
5ꢀCyclopropylꢀ3,5ꢀdi(methoxycarbonyl)ꢀ4,5ꢀdihydroꢀ1Hꢀ
pyrazole (7). A mixture of methyl acrylate (1.81 g, 21 mmol) and
diazo ester 1a (1.96 g, 14 mmol) was kept at 7—10 °С for 7 days.
Then, the excess of methyl acrylate was evaporated and the
residue was distilled in vacuo. Pyrazoline 7 (2.06 g, 65%) was
obtained as colorless liquid, b.p. 147—150 °С (12 Torr).
Found (%): C, 53.42; H, 6.48; N, 12.03. C10H14N2O4. Calcuꢀ
lated (%): C, 53.09; H, 6.24; N, 12.38. MS (EI), m/z (Irel (%)):
226 (5) [М]+, 195 (7) [М – OMe]+, 167 (85) [М – CO2Me]+,
135 (100) [М – CO2Me – MeOH]+. 1H NMR (CDCl3), δ: 0.49
(m, 4 Н, СН2СН2); 1.35 (tt, 1 Н, СН, Jcis = 8.2 Hz, Jtrans
=
5.6 Hz); 2.96 (dd, 1 Н, НaС(4), 2J = 17.4 Hz, 5J = 0.8 Hz); 3.51
(d, 1 Н, НbС(4), J = 17.4 Hz); 3.79, 3.83 (both s, 3 Н each,
2 OMe); 8.53 (br.s, 1 Н, NH). 13С NMR (CDCl3), δ: 1.13, 1.84
(СН2СН2); 17.35 (СН); 40.25 (С(4)); 52.10, 52.89 (2 OMe);
72.34 (С(5)); 142.30 (С(3)); 162.37, 174.15 (2 COO).
δ: 0.55, 0.92 (both m, CH2CH2); 1.67 (tt, 1 Н, СН, Jcis
=
7.9 Hz, Jtrans = 4.8 Hz); 3.76 (s, 3 Н, OMe). 13С NMR (CDCl3),
δ: 4.36 (СН); 6.96 (СН2СН2); 51.61 (ОМе); 59.87 (С=N2);
167.75 (COO).
3ꢀCyanoꢀ5ꢀcyclopropylꢀ5ꢀmethoxycarbonylꢀ4,5ꢀdihydroꢀ1Hꢀ
pyrazole (8). The product was obtained similarly from acryloꢀ
nitrile (1.11 g, 21 mmol) and diazo ester 1a (1.96 g, 14 mmol).
After distillation in vacuo, pyrazoline 8 (1.62 g, 60%) was obꢀ
tained as colorless liquid, b.p. 136—139 °C (12 Torr). Found (%):
C, 55.59; H, 5.48; N, 21.60. C9H11N3O2. Calculated (%):
C, 55.95; H, 5.74; N, 21.75. MS (EI), m/z (Irel (%)): 193
Allyl 2ꢀcyclopropylꢀ2ꢀdiazoacetate (1b). The esterification of
keto acid 3 was carried out similarly to the procedure used for
the esterification of cyclopropanecarboxylic acids10 with allyl
alcohol. The following manipulations were carried out similarly
to the preparation of diazo ester 1a, the yield of the target 1b was
62—65% calculated from keto acid 3. 1H NMR (CDCl3), δ:
0.56, 0.92 (both m, CH2CH2); 1.66 (tt, 1 Н, СН, Jcis = 7.9 Hz,
Jtrans = 4.8 Hz); 4.67 (dt, 2 Н, OCH2, 3J = 5.5 Hz, 4J ≈ 1.5 Hz);
5.22 (dq, 1 Н, =CHa, Jcis = 10.3 Hz, J ≈ 1.5 Hz); 5.31 (dq, 1 Н,
(5) [М]+, 134 (100) [М – CO2Me]+, 106 (40) [M
–
CO2Me – N2]+. 1H NMR (CDCl3), δ: 0.45, 0.56 (both m,
2 Н each, СН2СН2); 1.34 (tt, 1 Н, СН, Jcis = 8.1 Hz, Jtrans
=
5.7 Hz); 2.95 (dd, 1 Н, НaС(4), 2J = 17.3 Hz, 5J = 0.8 Hz); 3.46
2
(d, 1 Н, НbС(4), J = 17.3 Hz); 3.82 (s, 3 Н, OMe); 6.68 (br.s,
=CHb, Jtrans = 17.0 Hz, J ≈ 1.5 Hz); 5.92 (ddt, 1 Н, =СН, Jcis
=
1 Н, NH). 13С NMR (CDCl3), δ: 1.36, 2.14 (СН2СН2); 17.35
(СН); 42.39 (С(4)); 53.31 (OMe); 72.23 (С(5)); 113.85 (С≡N);
123.92 (C(3)), 173.33 (COO).
10.3 Hz, Jtrans = 17.0 Hz, 3J = 5.5 Hz).
Methyl cyclobutꢀ1ꢀenecarboxylate (6a). Diazo ester 1a
(1.96 g, 14 mmol) was slowly added to a stirred solution of
Rh2(OAc)4 (31 mg, 0.07 mmol) (or 25 mg of (PhO)3PСuCl) in
CH2Cl2 (15 mL). After gas evolution was over, the solvent was
evaporated to 1/4 of its initial volume, pentane (5 mL) was
added, and the mixture was filtered through a short layer of
silica gel. After the solvents were evaporated and the residue was
distilled in vacuo, colorless liquid (1.49 g, 95%) was obtained,
b.p. 74—76 °С (68 Torr), which, according to the 1Н NMR
spectrum in (CD3)2SO, was identical to methyl cyclobuteneꢀ
carboxylate 6a described earlier.15 1H NMR (CDCl3), δ: 2.48
(ddd, 2 Н, Н(3), J ≈ 3.5 Hz, J ≈ 3.0 Hz, J ≈ 1.2 Hz); 2.72 (dd,
2 Н, Н(4), J = 3.5 Hz, J = 3.0 Hz); 3.72 (s, 3 Н, OMe); 6.78 (t,
1 Н, Н(2), J = 1.2 Hz). 13С NMR (CDCl3), δ: 27.01 (С(3));
29.01 (С(4)); 51.03 (OMe); 138.38 (С(1)); 146.31 (С(2));
162.45 (COO).
Allyl cyclobutꢀ1ꢀenecarboxylate (6b). Diazo ester 1b (0.83 g,
5 mmol) was slowly added to a stirred solution of Rh2(OAc)4
(14 mg, 0.03 mmol) (or 11 mg of (PhO)3PСuCl) in CH2Cl2
(10 mL). After gas evolution was over, the solvent was evapoꢀ
rated to 1/5 of its initial volume, pentane (2 mL) was added, the
mixture was filtered through a short layer of silica gel, and the
solvents were evaporated in vacuo at a residual pressure of
20 Torr. A slightly yellowish liquid was obtained (0.70 g), which
virtually was a pure allyl cyclobutenecarboxylate 6b. 1H NMR
(CDCl3), δ: 2.46 (ddd, 2 Н, Н(3), J ≈ 3.5 Hz, J ≈ 3.0 Hz, J ≈
1.2 Hz); 2.73 (dd, 2 Н, Н(4), J = 3.5 Hz, J = 3.0 Hz); 4.63 (dt,
2 Н, OCH2, 3J = 5.5 Hz, 4J ≈ 1.5 Hz); 5.23 (dq, 1 Н, =CHa,
3ꢀCyclopropylꢀ3,5ꢀdi(methoxycarbonyl)ꢀ5ꢀmethylꢀ4,5ꢀdiꢀ
hydroꢀ3Нꢀpyrazole (9). A mixture of diazo ester 1a (0.56 g,
4 mmol) and methyl methacrylate (0.60 g, 6 mmol) was kept at
7—10 °С for 15 days. The excess of methyl methacrylate
and partially formed cyclobutene 6a were removed in vacuo
(~0.1 Torr) at the temperature below 15 °С. The residue was
dissolved in benzene (15 mL) and passed through a short layer of
silica. After the solvent was evaporated, a viscous liquid (0.53 g)
1
was obtained, which, according to the Н and 13С NMR specꢀ
tra, constituted a mixture of cisꢀ and transꢀpyrazolinediꢀ
carboxylates 9 (the yield was ~55%, the ratio of isomers, ~1 : 2.2)
with small admixture (~5%) of other compounds. cisꢀIsomer 9.
1H NMR (CDCl3), δ: 0.20, 0.59, 0.69, 0.85 (all m, 1 Н each,
СН2СН2); 1.28, 2.70 (both d, 1 Н each, Н2C(4), 2J = 13.5 Hz);
1.62 (m, 1 Н, СН); 1.72 (s, 3 Н, Me); 3.70, 3.78 (both s,
3 Н each, 2 ОMe). 13С NMR (CDCl3), δ: 1.31, 1.99 (СН2СН2);
17.53 (СН); 22.47 (Me); 36.45 (С(4)); 52.40, 52.49 (2 OMe);
95.92 (С(3)); 100.20 (С(5)); 170.00, 170.44 (2 COO).
transꢀIsomer 9. 1H NMR (CDCl3), δ: 0.21, 0.60 and 0.75 (all m,
1+2+1 Н, СН2СН2); 1.56 (s, 3 Н, Me); 1.70 (m, 1 Н, СН);
1.88, 1.99 (both d, 1 Н each, Н2C(4), J = 13.7 Hz); 3.81, 3.82
(both s, 3 Н each, 2 OMe). 13С NMR (CDCl3), δ: 1.05, 1.30
(СН2СН2); 16.49 (СН); 22.40 (Me); 34.40 (С(4)); 52.61, 52.65
(2 OMe); 96.68 (С(3)); 100.53 (С(5)); 170.65, 170.77 (2 COO).
Dimethyl 1ꢀcyclopropylꢀ2ꢀmethylcyclopropaneꢀ1,2ꢀdicarbꢀ
oxylate (10). Obtained in the preceding experiment reaction
mixture (0.46 g) was heated in CHCl3 (5 mL) at 50 °С for 1 h.

1520
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
Prokopenko et al.
After the solvent was evaporated by microdistillation in vacuo,
a mixture of cisꢀ and transꢀisomers of dimethyl 1ꢀcyclopropylꢀ2ꢀ
methylcyclopropaneꢀ1,2ꢀdicarboxylate (0.37 g, 92%) was isoꢀ
lated in the ratio ~1 : 2.3, b.p. 116—119 °С (7 Torr). Found (%):
C, 62.04; H, 7.49. C11H16O4. Calculated (%): C, 62.25; H, 7.60.
MS (EI), m/z (Irel (%)): 212 [М]+ (3), 180 [М – MeOH]+ (11),
152 [М – HCO2Me]+ (35), 137 (32), 120 (37), 93 [C7H9]+
(100). cisꢀIsomer 10. 1H NMR (CDCl3), δ: 0.21, 0.59, 0.38,
0.67 (all m, 1 Н each, СН2СН2); 0.71, 1.78 (both d, 1 Н each,
Н2C(3), 2J = 5.1 Hz); 1.35 (m, 1 Н, СН); 1.44 (s, 3 Н, Me);
3.64, 3.67 (both s, 3 Н each, 2 ОMe). 13С NMR (CDCl3), δ:
3.51, 5.33 (СН2СН2); 10.60 (СН); 14.94 (Me); 21.67 (С(3));
30.35 (С(1)); 39.67 (С(2)); 51.89, 51.95 (2 OMe); 172.37, 173.54
(2 COO). transꢀIsomer 10. 1H NMR (CDCl3), δ: 0.19, 0.57,
0.29, 0.43 (all m, 1 Н each, СН2СН2); 1.23, 1.39 (both d,
1 Н each, Н2C(3), J = 5.5 Hz); 1.28 (m, 1 Н, СН); 1.34 (s, 3 Н,
Me); 3.71, 3.75 (both s, 3 Н each, 2 OMe). 13С NMR (CDCl3),
δ: 3.38, 5.08 (СН2СН2); 9.92 (СН); 16.37 (Me); 19.05 (С(3));
31.63 (С(1)); 37.58 (С(2)); 51.87, 51.97 (2 OMe); 172.09,
172.18 (2 COO).
1ꢀCyclopropylꢀ2ꢀmethylcyclopropaneꢀ1,2ꢀdicarboxylic acid
(11). A solution of KOH (0.063 g, 1.1 mmol) in methanol (4 mL)
was added to a solution of diester 10 (0.085 g, 0.4 mmol)
(a mixture of isomers) in methanol (1 mL) and the mixture was
heated at 60 °С for 2 h. Then, methanol was evaporated, water
(8 mL) was added, this was acidified with 1 M HCl to pH 1—2
and extracted with ether (3×5 mL)). Etheral extract was dried
with anhydrous CaCl2. After evaporation of ether, acid 11
(0.067 g, ~90%) was obtained as yellowish oil (the ratio of cisꢀ and
transꢀisomers, ~1 : 2.5). 1H NMR (DMSOꢀd6), δ: 0.04, 0.19,
0.32, 0.48 (all m, СН2СН2); 0.62, 1.41 (both d, Н2С(3) in
minor isomer, J = 5.2 Hz); 0.97, 1.16 (both d, Н2С(3) in major
isomer, J = 5.3 Hz); 1.20 (m, СН); 1.22 (s, Ме in major isoꢀ
mer,); 1.28 (s, Ме in minor isomer); 12.40 (br.s, СООН).
13С NMR (CDCl3), δ: for transꢀisomer 11 3.21, 5.30 (СН2СН2);
10.10 (СН); 16.49 (Me); 18.40 (С(3)); 30.79 (С(1));
36.93 (С(2)); 172.44 (2 COO); for cisꢀisomer 11 4.87, 10.71
(СН2СН2); 15.00, 15.10 (СН, Me); 20.71 (С(3)); 29.55 (С(1));
С(2) signal overlaps with DMSO signal; 172.30, 174.04 (2 COO).
4ꢀCyclopropylꢀ1,4ꢀdi(methoxycarbonyl)ꢀ2,3ꢀdiazabiꢀ
cyclo[3.2.0]heptꢀ2ꢀene (12). А. A mixture of diazo ester 1a
(0.28 g, 2 mmol) and cyclobutenecarboxylate 6a (0.45 g, 4 mmol)
was kept at 7—10 °С for 14 days. The volatile compounds were
evaporated in vacuo (0.1 Torr, 30 °С), The residue was dissolved
in toluene (10 mL) and passed through a short column with
SiO2, eluting with toluene—AcOEt mixture (15 : 1). After evapoꢀ
ration of the solvents, a viscous yellowish liquid (0.20 g) was
obtained, which, according to the 1Н NMR spectra, was preꢀ
dominantly a mixture of isomeric pyrazolines 12 (the ratio of
synꢀ and antiꢀisomers, ~4.2 : 1).
Rf 0.47 (synꢀ12) and 0.53 (antiꢀ and synꢀ12 in the ratio ~3 : 1).
synꢀIsomer 12. Found (%): C, 57.51; H, 6.48; N, 10.85.
C
12H16N2O4. Calculated (%): C, 57.13; H, 6.39; N, 11.10.
MS (ESI), m/z: MS 275 [М + Na]+, MS/MS 247 [М +
Na – N2]+. 1H NMR (CDCl3), δ: 0.21, 0.50, 0.66 (all m,
1+2+1 Н, CH2CH2 in cyclopropane ring); 1.28 (tt, 1 Н, CH in
cyclopropane ring, Jcis = 8.5 Hz, Jtrans = 5.4 Hz); 1.35 (dddd,
1 Н, Ha(6), 2J = 13.1 Hz, J = 9.8 Hz, J = 7.8 Hz, J5,6a = 6.2 Hz);
2.17 (dddd, 1 Н, Hb(6), 2J = 13.1 Hz, J = 10.4 Hz, J5,6b
=
2
9.3 Hz, J = 5.1 Hz); 2.26 (dddd, 1 Н, Ha(7), J = 13.2 Hz, J =
9.8 Hz, J = 5.1 Hz, J5,7a = 1.2 Hz); 2.74 (dddd, 1 Н, Hb(7), 2J =
13.2 Hz, J = 10.4 Hz, J = 7.8 Hz, J5,7b = 1.0 Hz); 2.89 (ddt, 1 Н,
H(5), J5,6b = 9.3 Hz, J5,6a = 6.2 Hz, 4J ≈ 1.1 Hz); 3.82, 3.85
(both s, 3 Н each, 2 OMe). 13С NMR (CDCl3), δ: 1.08, 1.75
(СН2СН2); 17.35 (СН); 19.34 (С(6)); 27.45 (С(7)); 39.78
(C(5)); 52.50, 52.84 (2 OMe); 98.00 (С(4)); 103.48 (С(1));
1
168.89, 169.84 (2 COO). antiꢀIsomer 12. H NMR (CDCl3), δ:
0.57, 0.73, 1.16 (all m, 1+2+1 Н, CH2CH2 in cyclopropane
ring); 1.31 (m, 1 Н, CH in cyclopropane ring); 2.06 (m, 2 Н,
H(6)); 2.32 (m, 1 Н, Ha(7)); 2.78 (m, 1 Н, Hb(7)); 3.30 (ddt,
1 Н, H(5), J5,6b = 8.7 Hz, J5,6a = 7.0 Hz, 4J ≈ 1.1 Hz); 3.71, 3.74
(both s, 3 Н each, 2 OMe). 13С NMR (CDCl3), δ: 1.36, 2.89
(СН2СН2); 13.17 (СН); 16.27 (С(6)); 26.98 (С(7)); 41.50
(C(5)); 52.69, 52.81 (2 OMe); 99.06 (С(4)); 100.07 (С(1));
168.29, 171.01 (2 COO).
5ꢀCyclopropylꢀ1,5ꢀdi(methoxycarbonyl)bicyclo[2.1.0]penꢀ
tane (13). A solution of pyrazolines 12 (0.129 g, 0.51 mmol) (the
ratio of synꢀ and antiꢀisomers, ~4 : 1) in benzene (3 mL) was
refluxed for 1.5 h, then passed through a short layer of silica gel,
washed with benzene (3 mL), the solvent was evaporated in vacuo
to give a mixture of synꢀ and antiꢀisomers (~4 : 1, 1Н and
13С NMR spectra) of bicyclopentanedicarboxylate 13 (0.109 g,
~95%). In similar conditions, the thermolysis of pure synꢀisoꢀ
mer 12 gives a single synꢀisomer 13. synꢀIsomer 13. MS (EI),
m/z (Irel (%)): 224 (0.5) [М]+, 210 (1.5), 196 (12), 165 (13)
[М – CO2Me]+, 164 (10) [М – HCO2Me]+, 151 (15), 133 (17),
105 (20), 84 (100). 1H NMR (CDCl3), δ: 0.53, 0.72 (both m,
2 Н each, CH2CH2); 1.21 (tt, 1 Н, CH, Jcis = 8.5 Hz, Jtrans
=
5.4 Hz); 1.74 (dddd, 1 Н, Ha(3), 2J = 11.7 Hz, Jcis = 5.8 Hz,
Jtrans = 3.6 Hz, J3a,4 ≈ 1.2 Hz); 2.02 (dddd, 1 Н, Ha(2), 2J =
11.7 Hz, Jcis = 5.8 Hz, Jtrans = 4.3 Hz, J2a,4 ≈ 1.2 Hz); 2.21
(dddd, 1 Н, Hb(3), 2J = 11.7 Hz, Jcis = 10.5 Hz, Jtrans = 4.3 Hz,
J3b,4 = 4.8 Hz); 2.53 (ddd, 1 Н, Hb(2), 2J = 11.7 Hz, Jcis
=
10.5 Hz, Jtrans = 3.6 Hz); 2.79 (dt, 1 Н, H(4), J3b,4 = 4.8 Hz,
J3a,4 ≈ J2a,4 ≈ 1.2 Hz); 3.65, 3.66 (both s, 3 Н each, 2 OMe).
13С NMR (CDCl3), δ: 3.75, 6.21 (СН2СН2); 6.40 (СН); 16.84
(С(3)); 20.83 (С(2)); 34.03 (C(4)); 34.23 (C(5)); 43.25 (С(1));
51.37, 51.55 (2 OMe); 170.05, 171.23 (2 COO). antiꢀIsomer 13.
1H NMR (CDCl3), δ: 1.30 (m, CH); 3.70, 3.77 (both s, 2 OMe);
the rest of the signals overlap with the signals of the main
synꢀisomer. 13С NMR (CDCl3), δ: 3.70, 5.63 (СН2СН2); 10.41
(СН); 18.23 (С(3)); 23.22 (С(2)); 33.61 (C(4)); 34.38 (C(5));
46.27 (С(1)); 51.31, 51.52 (2 OMe); 170.34, 171.35 (2 COO).
5ꢀCyclopropylꢀ5ꢀmethoxycarbonylꢀ3,4ꢀdiazatricycloꢀ
[5.2.1.02,6]decꢀ3ꢀene (14). А. A mixture of norbornene (4.70 g,
0.05 mol), diazo ester 1a (2.10 g, 0.015 mol), and CH2Cl2
(0.3 mL) was kept for 14 days at 7 °С. Then, the volatile comꢀ
pounds were evaporated in vacuo (~0.5 Torr). The residue
(1.92 g) was obtained, which contained isomeric 3,4ꢀdiazatriꢀ
cyclodecenes 14 (syn : anti ≈ 2.5 : 1) with admixture of pyrꢀ
azolines 12. The reaction mixture obtained was separated by
B. Diazo ester 1a (0.70 g, 5 mmol) and cyclobutene 6a
(0.78 g, 7 mmol) were placed in a PTFEꢀtube and a few drops of
CH2Cl2 were added. The tube was placed into a highꢀpressure
reactor, the pressure was adjusted to 1000 MPa, and this was
kept for 24 h at 10 °С. After the experiment was over, the highꢀ
pressure unit was cooled to –20 °С, the pressure was released,
and the reaction mixture was treated as described above. Isoꢀ
meric pyrazolines 12 (0.96 g) were obtained (the yield, ~75%,
the ratio of synꢀ and antiꢀisomers, ~4 : 1). A part of the reacꢀ
tion mixture was separated by preparative TLC (SiO2, benꢀ
zene—AcOEt, 5 : 1 as the eluent), collecting a fraction with

2ꢀCyclopropylꢀ2ꢀdiazoacetic esters
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 8, August, 2007
1521
column chromatography (SiO2, toluene—AcOEt, 25 : 1 as the
eluent), receiving initially the minor antiꢀisomer, then, a mixꢀ
ture of isomers, further, individual synꢀisomer 14, and, finally,
a fraction, containing synꢀisomer 14 together with pyrazolines 12.
After evaporation of the solvents, the eluates were analyzed by
1Н NMR spectroscopy.
B. A mixture of norbornene (0.94 g, 10 mmol), diazo ester
1a (0.56 g, 4 mmol), and CH2Cl2 (0.3 mL) was placed into a
PTFEꢀtube, which was placed in a highꢀpressure reactor and
kept for 24 h at 1000 MPa. After the reaction was over, the
pressure was released, the mixture was cooled to –20 °С, and
the reaction mixture was concentrated in vacuo at ~0.2 Torr.
The residue was dissolved in benzene (10 mL) and passed through
a short layer of silica gel. After the solvent was evaporated,
pyrazolines 14 (0.74 g, 78%) were obtained as a slightly yelꢀ
lowish liquid, which was a mixture of synꢀ and antiꢀisomers
(~2.4 : 1). This was separated by chromatography as described
earlier. synꢀIsomer 14. Found (%): C, 66.19; H, 7.58; N, 12.24.
Research "Elaboration of Methods for the Synthesis of
Chemical Substances and Creation of New Materials",
Subprogram "Development of Methodology of Organic
Synthesis and Creation of Compounds with Valuable Apꢀ
plied Properties"), the Federal Agency for Science and
Innovations and the Russian Federation President Counꢀ
cil for Grants (Program for the State Support of Leading
Scientific Schools of RF, Grant NShꢀ6075.2006.3).
References
1. M. Regitz and H. Heydt, 1,3ꢀDipolar Cycloaddition Chemisꢀ
try, Ed. A. Padwa, Wiley Interscience, New York, 1984,
v. 1, p. 393.
2. G. Maas, The Chemistry of Heterocyclic Compounds,
Eds A. Padwa and W. H. Pearson, J. Wiley & Sons, Inc.,
2002, v. 59, p. 539.
3. O. M. Nefedov, E. A. Shapiro, and A. B. Dyatkin, Diazoacetic
Acids and Derivatives, Ed. Patai Saul, Wiley, Chichester,
UK, 1992, 2 (Pt. 2), 1475ꢀ1637.
4. G. Maas, Top. Curr. Chem., 1987, 137, 75.
5. (a) M. P. Doyle, M. A. McKervey, and T. Ye, Modern Cataꢀ
lytic Methods for Organic Synthesis with Diazo Compounds;
Wiley, New York, 1998, 652 pp.; (b) Ibid. p. 238.
6. M. B. Sohn and M. Jones, Jr., J. Am. Chem. Soc., 1972,
94, 8280.
7. R. R. Gallucci and M. Jones, Jr., J. Am. Chem. Soc., 1976,
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11. W. von der Saal, R. Reinhardt, H.ꢀM. Seidenspinner,
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C
13H18N2O2. Calculated (%): C, 66.64; H, 7.74; N, 11.96.
MS (EI), m/z (Irel (%)): 234 (2) [M]+, 206 (6) [М – N2]+, 178
(19), 146 (26), 105 (82), 91 (82), 79 (70), 59 (63); 41 (100).
1H NMR (CDCl3), δ: –0.12, 0.43, 0.72 (all m, 1+2+1 Н,
СН2СН2); 0.66 (dq, 1 Н, synꢀН(10), 2J = 10.5 Hz, J ≈ 1.5 Hz);
0.89 (dq, 1 Н, antiꢀН(10), 2J = 10.5 Hz, J ≈ 1.8 Hz); 1.15 (m,
1 Н, endoꢀH(8)); 1.31 (m, 1 Н, endoꢀH(9)); 1.45 (m, 2 Н,
exoꢀH(8) and СН in cyclopropane ring); 1.58 (m, 1 Н,
exoꢀH(9)); 1.71 (dd, 1 Н, Н(6), 3J = 6.8 Hz, J ≈ 1.8 Hz); 1.99
3
(m, 1 Н, Н(7)); 2.89 (m, 1 Н, Н(1), J1,9exo = 4.8 Hz); 3.83 (s,
3 Н, OMe); 4.57 (dt, 1 Н, Н(2), 3J = 6.8 Hz, J ≈ 1.5 Hz).
13С NMR (CDCl3), δ: 0.33, 0.59 (СН2СН2); 18.69 (CH); 25.29
(C(9)); 28.68 (C(8)); 32.25 (С(10)); 38.16, 38.41 (С(1), С(7));
47.63 (С(6)); 51.82 (OMe); 97.55 (С(2)); 98.69 (С(5)); 170.95
(COO). antiꢀIsomer 14. 1H NMR (CDCl3), δ: 0.45, 0.73, 1.10
(all m, 1+2+1 Н, СН2СН2); 0.68 (m, 1 Н, synꢀН(10)); 1.00
2
(dq, 1 Н, antiꢀН(10), J = 10.5 Hz, J ≈ 1.5 Hz); 1.17 (m, 1 Н,
endoꢀH(8)); 1.30 (m, 2 Н, endoꢀH(9), СН in cyclopropane
ring); 1.46 (m, 1 Н, exoꢀH(8)); 1.61 (m, 1 Н, exoꢀH(9)); 2.01
3
(dd, 1 Н, Н(6), J = 6.8 Hz, J ≈ 1.8 Hz); 2.38 (m, 1 Н, Н(7));
2.99 (m, 1 Н, Н(1), 3J1,9exo = 4.8 Hz); 3.69 (s, 3 Н, OMe); 4.63
3
(dt, 1 Н, Н(2), J = 6.8 Hz, J ≈ 1.5 Hz). 13С NMR (CDCl3), δ:
1.57 and 3.34 (СН2СН2); 12.80 (CH); 25.31 (C(9)); 28.72
(C(8)); 33.53 (С(10)); 36.85 С(7)); 38.52 (С(1)); 46.96 (С(6));
52.36 (OMe); 97.70 (С(5)); 98.63 (С(2)); 171.59 (COO).
13. M.ꢀA. Plancquaert, Ph. François, R. Merényi, and H. G.
Viehe, Tetrahedron Lett., 1991, 32, 7265.
14. A. P. Meshcheryakov and V. G. Glukhovtsev, Izv. Akad.
Nauk SSSR, Otd. Khim. Nauk, 1959, 1490 [Bull. Acad. Sci
USSR, Div. Chem. Sci., 1959, 7 (Engl. Transl.)].
15. R. J. Griffin, C. E. Arris, C. Bleasdale, F. T. Boyle, A. H.
Calvert, N. J. Curtin, C. Dalby, S. Kanagula, N. K. Lembicz,
D. R. Newell, A. E. Pegg, and B. T. Golding, J. Med. Chem.,
2000, 43, 4071.
Authors are grateful to Yu. A. Strelenko (N. D.
Zelinsky Institute of Organic Chemistry, RAS) for the
systematic help in recording 1H and 13С spectra on a
Bruker DRXꢀ500 spectrometer and D. I. Moskvin (N. D.
Zelinsky Institute of Organic Chemistry, RAS) for the
help in carrying out the highꢀpressure experiments.
This work was financially supported by the Presidium
of the Russian Academy of Sciences (Program for Basic
Received April 5, 2007