Catalytic [2+1] cycloaddition of diazo compounds to [60]fullerene

Article abstract of DOI:10.1007/s11172-009-0238-5

A catalytic method for the efficient synthesis of 5,6-open and 6,6-closed (2π+1π) fullerene adducts by [2+1] cycloaddition of ethyl 2-alkyl(hetaryl)-2-diazoacetates to [60]fullerene in the presence of a three-component catalyst Pd(acac)₂-PPh₃-Et₃Al have been developed.

Full text of DOI:10.1007/s11172-009-0238-5

Russian Chemical Bulletin, International Edition, Vol. 58, No. 8, pp. 1724—1730, August, 2009
1724
Catalytic [2+1] cycloaddition of diazo compounds
to [60]fullerene
A. R. Tuktarov, A. R. Akhmetov, D. Sh. Sabirov, L. M. Khalilov, A. G. Ibragimov, and U. M. Dzhemilev
Institute of Petrochemistry and Catalysis, Russian Academy of Sciences,
141 prosp. Oktyabrya, 450075 Ufa, Russian Federation.
Fax: +7 (347) 284 2750. Eꢀmail: ink@anrb.ru
A catalytic method for the efficient synthesis of 5,6ꢀopen and 6,6ꢀclosed (2π+1π) fullerene
adducts by [2+1] cycloaddition of ethyl 2ꢀalkyl(hetaryl)ꢀ2ꢀdiazoacetates to [60]fullerene in the
presence of a threeꢀcomponent catalyst Pd(acac)2—PPh3—Et3Al have been developed.
Key words: metal complex catalysis, [60]fullerene, diazo compounds, [2+1] cycloaddition.
Substituted cyclopropafullerenes are promising comꢀ
selectivity among transition metal complexes tested. In
this regard, all subsequent experiments were carried out
using this catalytic system.
pounds that could find applications in medicine and agriꢀ
culture, as high energy fuel components and the heavy
machinery lubricant additives.1—13 Cyclopropafullerenes
are usually obtained by cyclopropanation of fullerene with
malonic acid derivatives following the Bingel proceꢀ
dure,14,15 as well as by thermal16 or catalytic17 [2+1] cyꢀ
cloaddition of diazo compounds to [60]fullerene. The pubꢀ
lished data16,17 suggest that the known synthetic methꢀ
ods towards cyclopropafullerenes have low effectiveness
or require stoichiometric amounts of such highly expenꢀ
sive promoters as ruthenium complexes. Besides, the yields
of the target compounds are low.
The thermal cycloaddition reaction of diazoacetates
to [60]fullerene yielded 5,6ꢀopen (homofullerenes) and
6,6ꢀclosed (methanofullerenes or cyclopropafullerenes)
adducts in ~35% total yield. Separation of the reaction
mixture into the individual adducts is very difficult and,
in some cases, is not possible.
Recently,18 we have reported the synthesis of cycloꢀ
propafullerenecarboxylates with high yields by cycloaddiꢀ
tion of ethyl diazoacetate to [60]fullerene in the presence
of palladium complexes. In continuation of this research,
in the present work we studied [2+1] cycloaddition of ethyl
2ꢀalkyl(hetaryl)ꢀ2ꢀdiazoacetates and other substituted diꢀ
azo compounds to [60]fullerene in the presence of palladiꢀ
um complexes. The effect of the solvents and ratio of the
catalytic system components as well as the bulkiness of
the alkyl substituent in starting diazo compound on the
yield and selectivity have also been studied.
It has been found that the reaction of ethyl 2ꢀmethylꢀ
2ꢀdiazoacetate with [60]fullerene (molar ratio 5 : 1) in the
presence of 20 mol.% of Pd(acac)2—PPh3—Et3Al (1 : 2 : 4)
at 20 °C (18 h, oꢀdichlorobenzene) resulted in a mixture of
6,6ꢀclosed (1) and 5,6ꢀopen (2) fullerene adducts along
with the corresponding bisꢀcyclopropane derivatives 3 and
4 in the ratio (1 + 2) : (3 + 4) ~3 : 1 in ~77% total yield
(Scheme 1). No noticeable increase in the total yield
(~79%) and changes in the ratio of adducts 1, 2 and 3, 4
were observed when the reaction time was prolonged up to
30 h. Similar results were obtained on increase in the reaction
temperature to 40 and 80 °C with concomitant reduction
of the reaction time from 18 to 1.5 and 0.5 h, respectively.
The mixture of monoꢀ (1, 2) and bisꢀadducts (3, 4)
was separated using semiꢀpreparative HPLC. The data
obtained from the 1H and 13C NMR and 2D experiments
(HHCOSY, HSQC, HMBC) of 1, 2 and 3, 4 indicated
that a mixture of monoꢀadducts 1 and 2 along with
a mixture of regioisomers of bisꢀadducts 3 and 4 were
formed under the described conditions.
In accordance with the 1H NMR spectral data,
5,6ꢀopen adduct 2 was the main component in the mixꢀ
ture 1 + 2 (signal ratio 1 : 6). The singlet signal for the
methyl group of adduct 2 appeared in the lower field (δH
1
3.22) than that of 1 (δH 2.54). The H NMR spectrum of
the mixture 1 + 2 exhibited two sets of quartets (δH 4.53,
J = 7.2 Hz, and 4.23, J = 7.2 Hz) and triplets (δH 1.53,
J = 7.2 Hz, and 1.36, J = 7.2 Hz) assigned to the ethyl
protons of the ester group. These data are in accord with
previously published data16,18 on the cycloaddition of ethꢀ
yl diazoacetate to [60]fullerene, which suggests the forꢀ
mation of cyclopropafullerene 1 and 5,6ꢀopen adduct 2
with the methyl group arranged above the plane of a
Results and Discussion
A threeꢀcomponent catalyst prepared from Pd(acac)2,
PPh3, and Et3Al turned out to be particularly efficient in
the reaction under study showing the highest activity and
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1671—1677, August, 2009.
1066ꢀ5285/09/5808ꢀ1724 © 2009 Springer Science+Business Media, Inc.

[2+1] Cycloaddition of diazo compounds to C60
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 8, August, 2009
1725
Scheme 1
i.
, Pd(acac)2—PPh3—Et3Al (1 : 2 : 4).
fullerene pentagon. Due to the low content of adduct 1 in
the mixture, its 13C NMR spectrum showed four signals
with low intensities, which were attributed to ethyl (δC
62.24 and 14.39) and methyl (δC 15.50) carbon atoms and
the bridging C atom (δC 44.19). The 13C NMR spectrum
of isomer 2 contained 28 signals in the region characterisꢀ
tic of fullerene at δC 133—148, with two of them (δC 135.41
and 143.65) being of double intensity. The bridging C atom
(δC 53.44) is bound to the methyl group, which exhibited a
singlet signal at δH 3.22 thus confirming the formation of
adduct 2 of the proposed structure.
In the HMBC experiment of isomeric mixture 1 + 2
(Figs 1 and 2), the crossꢀpeaks of the methyl hydrogens at
the corresponding bridging C atoms with the fullerene
βꢀC atoms were observed. Thus interactions of the proꢀ
tons of the methyl group (δH 3.22) with the bridgehead
(δC 136.61) and bridging (δC 53.44) carbon atoms, as well
as with the carbonyl C atom were observed for the main
adduct 2. The highfield signal for the methyl protons of
the adduct 1 exhibited three crossꢀpeaks with the bridgꢀ
ing, sp3ꢀhybridized, and carbonyl C atoms at δC 44.19,
76.47, and 167.60, respectively.
methyl groups at the bridging C atoms, which exhibited
also seven signals at δC 52.78, 52.89, 52.96, 53.23, 53.46,
53.44, and 53.51. This pattern of the spectrum could sugꢀ
gest the formation of seven regioisomers regarding symꢀ
metric alignment of the methyl groups. The 13C NMR
spectrum of bisꢀadduct 4 exhibited four signals for the
ethyl groups at δC 14.12, 14.29, 61.39, and 61.49 and four
signals for the carbonyl groups at δC 169.09, 169.11,
169.23, and 169.34. This spectral pattern showed coinciꢀ
dence of the position for the signals for the ester methylꢀ
ene group for the most of the regioisomers of adduct 4.
The 13C NMR spectrum of the mixture 3 + 4 exhibited
signals for the regioisomeric 6,6ꢀclosed adduct 3. The sigꢀ
nals for the bridging C atoms appeared at δC 15.35, 15.53,
and 15.66, while the signals for the ethyl C atoms coincidꢀ
ed, as only one set of the ethyl group signals appeared
δ
20
Thermal isomerization of the monoꢀadducts 1 + 2 (reꢀ
fluxing in toluene for 11 h) resulted in 6,6ꢀclosed adduct 1
with quantitative yield.
The structure of the 6,6ꢀclosed adduct was confirmed
using mass MALDI—TOF mass spectrometry. Thus for
compound 1 the experiments operated in the linear and
reflection modes with recording of positive and negative
ions revealed a molecular ion with m/z 820.
40
60
80
100
120
140
160
The data from the 13C NMR spectra of the bisꢀadducts
3 and 4 showed that the increase in the number of the
isomers with respect to the arrangement of the substituꢀ
ents in the fullerene core resulted in the increase in the
number of signals characteristic of ethyl, methyl, and carꢀ
bonyl groups. The 5,6ꢀopen adduct 4 was found to be the
6
5
4
3
2
1
δ
main product in the mixture of bisꢀadducts 3 + 4. The 13
C
Fig. 1. HMBC Experiment for a mixture of fullerene adducts 1
and 2 (1H at 400.13 MHz, 13C at 100.62 MHz, solvent,
CS2—CDCl3 (5 : 1)).
NMR spectrum of adduct 4 contained 7 signals at δC 25.08,
25.27, 25.34, 25.38, 25.60, 25.67, and 25.93 attributed to

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Russ.Chem.Bull., Int.Ed., Vol. 58, No. 8, August, 2009
Tuktarov et al.
(PRIRODA 2.02+ program package),21 which correctꢀ
ly reproduced the energy and geometry parameters of
fullerenes22 and their derivatives.23 Since the cyclopropaꢀ
nation of unsaturated hydrocarbons with carbenes exhibꢀ
its high reaction rates and low activation energy,24 the
thermal effect of the reaction was chosen as a value charꢀ
acteristic of the reaction probability.
Thus the addition of the carbene to nonequivalent
6,6ꢀbonds of monoꢀadduct 1 resulted in nine regioisomers
(Fig. 4) depending on the relative orientation of Me and
COOEt groups, each of these regioisomers could exist as
two stereoisomers (in,in or in,out). The equal probability
of the formation of the isomers differing in the Me and
COOEt groups arrangement was confirmed by small difꢀ
ference in thermal effects of addition reactions leading to
in,inꢀ or in,outꢀisomers (Table 1).
The reactions that resulted in nine pairs of isomeric
bisꢀadducts are exothermic with thermal effects –ΔrH°
in the range of 205.0—276.9 kJ mol–1. The difference in
–ΔrH° values of the formed bisꢀadducts was very small.
Only for cisꢀ1 (in,in and in,out) isomers, the thermal
effects decreased by ~50 kJ mol–1 in respect of the
other isomeric bisꢀadducts due to the interaction between
cyclopropane rings annulated by 6,6ꢀbonds of the same
hexagon.
The influence of the ratio of the catalytic system
Pd(acac)2—PPh3—Et3Al components (Table 2) and the
solvent effects (Table 3) on the yield of adducts 1 and 2
were studied on the model reaction of [60]fullerene with
ethyl 2ꢀmethylꢀ2ꢀdiazoacetate.
From the data presented in Table 2 followed that the
increase in the concentration of PPh3 in the threeꢀcomꢀ
ponent catalytic system resulted in the increase in the
Fig. 2. Longꢀrange interaction of methyl group protons with C
atoms of the fullerene skeleton in the HMBC experiment
(the chemical shifts are given in the δ scale).
(δC 62.20 and 14.39). Unfortunately, no signals for the
carbonyl groups, bridging, and sp3ꢀhybridized C atoms
could be detected due to their low intensity and small
content of 6,6ꢀclosed bisꢀadduct 3 in the mixture. The
fullerene skeleton of the 3 + 4 mixture exhibited 70 signals
in the range of δ 130—150 (Fig. 3).
The thermal isomerization of the bisꢀadduct 4 in the
mixture 3 + 4 into bisꢀadduct 3 were observed (toluene,
110 °C, 16 h).
In accordance with the 1H NMR spectral data of therꢀ
mal isomerization of adducts 3 + 4, the intensity of the
methyl proton signals in the range of δH 2.4—2.6 increased
significantly due to the increase in the content of
6,6ꢀclosed isomers 3. The 1H NMR spectrum of adduct 3
exhibited nine signals (δH 2.43, 2.46, 2.47, 2.48, 2.49, 2.51,
2.55, 2.56, and 2.58) characteristic of the methyl groups at
the bridging C atoms, which could suggest the formation
of nine regioisomers of bisꢀadduct 3 regarding symmetric
alignment of the methyl groups. The structure of the adꢀ
duct 3 was confirmed by mass spectral data (m/z 920) that
were collected in the linear mode with registration of the
more informative negative ions.
Table 1. Calculated thermal effects (Δ H) of addition reaction of
r
ethoxycarbonyl(methyl)carbene to monoꢀadduct 1
With the aim at analyzing the structure of regioisomers
of bisꢀadduct 3, whose formation seemed more probable,
we calculated the thermal effects of the model addition
reaction of a carbene generated by decomposition of ethyl
2ꢀmethylꢀ2ꢀdiazoacetate to monoꢀadduct 1. The calꢀ
culations were implemented within the framework of
the density functional theory at the PBE/3z level19,20
Bisꢀadduct
Δ H°/kJ mol–1
r
cisꢀ1
cisꢀ2
cisꢀ3
transꢀ1
transꢀ2
transꢀ3
transꢀ4
eedge
205.0
264.2
264.3
273.1
272.2
275.4
268.4
276.9
273.0
215.7
264.2
264.6
269.7
272.5
277.6
268.8
274.7
275.7
160 140 120 100
80
60
40
20
δ
Fig. 3. 13C NMR spectrum of the mixture of bisꢀadducts 3 and 4
(solvent, CS2—CDCl3 (5 : 1)).
eface

[2+1] Cycloaddition of diazo compounds to C60
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 8, August, 2009
1727
Table 2. Influence of molar ratio of the catalytic system
Pd(acac)2—PPh3—Et3Al components on the yield (Y1+2) and
ratio of adducts 1 and 2
Pd(acac)2—PPh3—Et3Al
Y1+2 (%)
1 : 2
1 : 1 : 4
1 : 2 : 4
1 : 3 : 4
1 : 4 : 4
52
57
50
56
1 : 6
1 : 6
1 : 4
2 : 1
Note. Reaction conditions: оꢀdichlorobenzene, 80 °C, 0.5 h.
Fig. 4. Possible regioisomers of bisꢀadduct 3.
Table 3. Solvent effect on the yield (Y1+2) and ratio of adꢀ
ducts 1 and 2
6,6ꢀclosed adduct 1 yield. The same result can be obtained
for the reaction carried out in 1,2,4ꢀtrichlorobenzene in
the presence of the catalytic system Pd(acac)2—PPh3—
—Et3Al (1 : 2 : 4) (see Table 3). The replacement of 1,2,4ꢀtriꢀ
chlorobenzene by oꢀdichlorobenzene led mainly to
5,6ꢀopen adduct 2. The content of bisꢀadducts 3 and 4 did
not exceed 10% in all experiments. Thus, the changes in
the [Pd] : PPh3 ratio in the threeꢀcomponent catalytic sysꢀ
tem or the solvent led preferably to predominant formaꢀ
tion of 6,6ꢀclosed (1) or 5,6ꢀopen adducts (2).
Solvent
Y1+2 (%)
1 : 2
Benzene
Chlorobenzene
47
57
57
53
40
49
50
1 : 2
1 : 4
1 : 6
5 : 1
1 : 3
1 : 2
1 : 4
oꢀDichlorobenzene
1,2,4ꢀTrichlorobenzene
Toluene
1,3ꢀDimethylbenzene
1ꢀMethylnaphtalene
The effect of the bulkiness of the αꢀalkyl substituent of
the diazo compound on the yield and selectivity of the
reaction under consideration were also studied. The reacꢀ
tions of [60]fullerene with ethyl 2ꢀethylꢀ, 2ꢀisobutylꢀ, and
2ꢀbenzylꢀ2ꢀdiazoacetates were used as examples (Scheme
2). It was found that under optimum conditions (80 °C,
0.5—1.0 h, Pd(acac)2—PPh3—Et3Al (1 : 2 : 4)) [60]fulꢀ
lerene reacted with the aboveꢀmentioned diazo compounds
(molar ratio 1 : 5) to give the corresponding monoꢀ and
bisꢀadducts.
The data from 1H and 13C NMR spectra of compounds
5—10 suggested that the reaction of [60]fullerene with
ethyl 2ꢀisobutylꢀ2ꢀdizoacttate and ethyl 2ꢀbenzylꢀ2ꢀdiꢀ
azoacetate (in contrast with ethyl 2ꢀmethylꢀ2ꢀdiazoaceꢀ
tate) yielded stereoisomers of 5,6ꢀopen adducts (7a,b)
with alkyl substituents located above the plane of the
[60]fullerene hexagon along with a mixture of monoꢀadꢀ
ducts (5b, 6b and 5c, 6c). The total yields (and ratios)
Note. Reaction conditions: 80 °С, 0.5 h, Pd(acac)2—PPh3—Et3Al
(1 : 2 : 4).
of adducts 5, 6, and 7 synthesized from ethyl 2ꢀethylꢀ,
2ꢀisobutylꢀ, and 2ꢀbenzylꢀ2ꢀdiazoacetates were 54 (2 : 1 : 0),
51 (11 : 6 : 1), and 65 (4 : 4 : 1), respectively. No sigꢀ
nificant changes were observed for the reactions carꢀ
ried out under milder conditions (20 °C, 40 h), except
for the reaction of [60]fullerene with ethyl 2ꢀisobutylꢀ2ꢀ
diazoacetate, where the yield of the adducts 5b, 6b, and
7a decreased twofold. In the studied reactions, the
bisꢀadducts 8—10 were also formed in minor amounts
(less than 8% according to HPLC). No spectral anaꢀ
lysis of the bisꢀadducts 8—10 was performed due to
their low content in the mixtures. The arragenment of
the alkyl substituents in stereoisomers 6a—c and 7a,b
was assigned by comparing the spectral data of these
Scheme 2
R = Et (5a, 6a), Bui (5b, 6b, 7a), Bn (5c, 6c, 7b)

1728
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 8, August, 2009
Tuktarov et al.
Scheme 3
i. 80 °C, 1 h, Pd(acac)2—PPh3—Et3Al (1 : 2 : 4).
on a Specord 75 IR (Carl Zeiss Jena) spectrophotometer in KBr
pellets, the UV spectra were recorded on a Specord Mꢀ40 and
Specord Mꢀ80 instruments in CHCl3. 1H and 13C NMR spectra
were recorded on a Bruker Avanceꢀ400 spectrometer at 400.13
and 100.62 MHz, respectively. A mixture of CDCl3 and CS2
(1 : 5) was used as a solvent. The negativeꢀion mass spectra
were obtained on a MALDI TOF/TOF AutoflexꢀIII Bruker mass
spectrometer without a matrix operating in a linear mode.
Samples were dissolved in toluene prior to application on a metꢀ
al target.
[2+1] Cycloaddition of diazo compounds to [60]fullerene (genꢀ
eral procedure). Solutions of Pd(acac)2 (0.00278 mmol) in
oꢀdichlorobenzene (0.4 mL) and PPh3 (0.00556 mmol) in oꢀdichloꢀ
robenzene (0.42 mL) were placed in a glass reactor, cooled to
–5 °C, and a solution of Et3Al (0.01112 mmol) in toluene (0.1 mL)
was added with stirring under argon. The color changed from
pale yellow to pale brown. To the resulting catalyst, a solution of
[60]fullerene (0.0139 mmol) in oꢀdichlorobenzene (1.0 mL) was
added at ~20 °C, the color of the mixture turned to dark green.
The mixture was heated to 40 or 80 °C and a solution of ethyl
2ꢀalkyl(hetaryl)ꢀ2ꢀdiazoacetate (0.0695 mmol) in oꢀdichlorobenꢀ
zene (0.5 mL) was added dropwise in 5 min. The mixture was
stirred for 0.5—1.5 h at the corresponding temperature. Then
the reaction mixture was cooled to room temperature and treatꢀ
ed with aqueous HCl. After addition of toluene (7 mL), the
organic layer was passed through a small layer of silica gel. The
products 1—6 were separated by preparative HPLC using toluꢀ
ene as the eluent. Thermal isomerization of 5.6ꢀopen isomers
into 6,6ꢀadducts was carried out in accordance with the known
procedure.16,18
compounds with those of the specimens synthesized
previously by reaction of [60]fullerene with ethyl diazoꢀ
acetate.16,18
It should be noted that under the conditions found
(80 °C, 1 h, 20 mol.% Pd(acac)2—PPh3—Et3Al (1 : 2 : 4))
the [2+1] cycloaddition of ethyl 3ꢀ(1Hꢀindolꢀ3ꢀyl)ꢀ2ꢀdiꢀ
azopropionate to [60]fullerene occurred very selectively
and resulted in monoꢀadducts 11 and 12 in ~40% total
yield (Scheme 3). The adducts 11 and 12 could be obꢀ
tained with the same yield when the reaction was carried
out at ~20 °C for 21 h. In these experiments, no formation
of bisꢀadducts was observed.
Based on the data from 1D (1H and 13C NMR) and 2D
(HHCOSY, HSQC, HMBC) experiments, we found that
the reactions under study yielded 6,6ꢀclosed (11) and
5,6ꢀopen (12) adducts with the indolylmethyl substituent
above the plane of the fiveꢀmembered ring of fullerene.
The ratio of isomers 11 and 12 were determined from
1H NMR spectral data being 6 : 1 and 2 : 1 at 80 and 20 °C,
respectively.
In summary, it was experimentally shown that [2+1] cyꢀ
cloaddition of alkylꢀ and hetarylꢀsubstituted ethyl 2ꢀdiꢀ
azoacetates to [60]fullerene in the presence of a threeꢀ
component catalytic system Pd(acac)2—PPh3—Et3Al
readily gives 6,6ꢀclosed or 5,6ꢀopen adducts with fairly
high yields. It was shown that the structure of the products
depended on the ratio of the components in the catalytic
system, solvents, and reaction conditions. With the inꢀ
crease in the balkiness of the αꢀalkyl substituent in diꢀ
azoacetates, their reactivity decreased, while the yield of
6,6ꢀclosed adducts increased.
1´ꢀMethylꢀ1´ꢀethoxycarbonylꢀ(C60ꢀIh)[2´,3´:1,9]cycloproꢀ
pa[5,6]fullerene (1). IR, ν/cm–1: 540; 820; 1040; 1110; 1270;
1
1660. UV, λmax/nm: 260, 327, 424. H NMR, δ: 1.53 (t, 3 H,
Me, J = 7.2 Hz); 2.54 (s, 3 H, Me); 4.53 (q, 2 H, CH2, J = 7.2 Hz).
13C NMR, δ: 14.39, 15.50, 44.19, 62.24, 76.47 (sp3), 138.17,
138.35, 140.92, 141.15, 142.08, 142.14, 142.24, 142.30, 142.97,
143.05, 143.12, 143.31, 143.71, 143.93, 144.29, 144.60, 144.62,
144.70, 144.83, 145.20, 145.23, 145.25, 145.58, 146.31, 147.60,
167.60 (CООEt). MS, m/z: 820 [M]+.
Experimental
Commercially available [60]fullerene (99.5% pure, G. A.
Razuvaev Institute of Organometallic Chemistry, Russian Acadꢀ
emy of Sciences, Nizhniy Novgorod) was used. The reaction
products were analyzed using an HPLC chromatograph Altex
(model 330) (USA) equipped with a UV detector (340 nm). The
mixtures were separated on metal column Cosmosil Buckyprep
Waters (250×10 mm) at ~20 °C. Toluene was used as the eluent,
the flow rate was 2.0 mL min–1. The IR spectra were registered
1´aꢀMethylꢀ1´aꢀethoxycarbonylꢀ1´aꢀcarbaꢀ1´(2´)aꢀhomoꢀ
(C60ꢀIh)[5,6]fullerene (2). IR, ν/cm–1: 520; 1080; 1120; 1200;
1
1740. UV, λmax/nm: 262, 333. H NMR, δ: 1.36 (t, 3 H, Me,
J = 7.2 Hz); 3.22 (s, 3 H, Me); 4.23 (q, 2 H, CH2, J = 7.2 Hz).
13C NMR, δ: 14.08, 25.52, 53.44, 61.50, 134.06, 134.64, 135.41,
136.61, 137.65, 138.31, 138.67, 138.72, 139.91, 140.56, 141.41,
141.58, 141.75, 141.90, 142.21, 142.56, 142.59, 142.69, 142.88,

[2+1] Cycloaddition of diazo compounds to C60
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 8, August, 2009
1729
142.95, 143.15, 143.29, 143.48, 143.65, 143.83, 144.51, 144.73,
147.26, 167.60 (COOEt).
1´ꢀBenzylꢀ1´ꢀethoxycarbonyl(C60ꢀIh)[2´,3´:1,9]cyclopropaꢀ
[5,6]fullerene (5c). IR, ν/cm–1: 520; 1180; 1210; 1430; 1630;
1730. UV, λmax/nm: 260, 329, 425. H NMR, δ: 1.34 (t, 3 H,
1
1
Bisꢀadduct 3. H NMR, δ: 1.47—1.55 (m); 2.43, 2.46, 2.47,
2.48, 2.49, 2.51, 2.55, 2.56, and 2.58 (all s); 4.45—4.55 (m).
13C NMR, δ: 14.39, 15.35, 15.53, 15.66, 44.26, 44.49, 45.26,
45.55, 50.02, 62.20, 138—147, 167.54 (COOEt), 167.61
(COOEt), 167.63 (COOEt), 167.76 (COOEt). MS, m/z: 920 [M]+.
Bisꢀadduct 4. 1H NMR, δ: 1.29—1.38 (m); 3.03, 3.05, 3.12,
3.17, 3.19, 3.21 and 3.25 (all s); 4.18—4.29 (m). 13C NMR, δ:
14.12, 14.29, 25.08, 25.27, 25.34, 25.38, 25.60, 25.67, 25.93,
52.78, 52.89, 52.96, 53.23, 53.46, 53.44, 53.51, 61.39, 61.49,
128—147, 169.09 (COOEt), 169.11 (COOEt), 169.23 (COOEt),
169.34 (COOEt).
Me, J = 7.2 Hz); 4.25 (s, 2 H, CH2); 4.37 (q, 2 H, CH2, J = 7.2 Hz);
7.21 (t, H, CH, J = 7.2 Hz); 7.43 (t, 2 H, 2 CH, J = 7.2 Hz); 7.60
(d, 2 H, 2 CH, J = 7.6 Hz). 13C NMR, δ: 14.53, 35.26, 50.20,
62.45, 76.01 (sp3), 127.67 (Ph), 129.03 (Ph), 129.23 (Ph), 136.55
(Ph), 138.09, 140.27, 141.16, 141.57, 142.08, 142.21, 142.27,
142.96, 143.06, 143.14, 143.21, 143.74, 143.96, 144.38, 144.61,
144.68, 144.71, 144.88, 145.25, 145.27, 145.30, 145.35, 145.51,
146.82, 147.88, 166.31 (COOEt). MS, m/z: 896 [M]+.
1´aꢀBenzylꢀ1´aꢀethoxycarbonylꢀ1´aꢀcarbaꢀ1´(2´)aꢀhomoꢀ
(C60ꢀIh)[5,6]fullerene (6c). IR, ν/cm–1: 510; 680; 720; 1180;
1
1´ꢀEthylꢀ1´ꢀethoxycarbonylꢀ(C60ꢀIh)[2´,3´:1,9]cyclopropaꢀ
1720. UV, λmax/nm: 262, 333. H NMR, δ: 1.12 (t, 3 H, Me,
[5,6]fullerene (5a). IR, ν/cm–1: 530; 1130; 1180; 1200; 1230;
J = 7.2 Hz); 3.98 (q, 2 H, CH2, J = 7.2 Hz); 5.16 (s, 2 H, CH2);
7.22 (t, H, CH, J = 7.2 Hz); 7.44 (t, 2 H, 2 CH, J = 7.2 Hz); 7.46
(d, 2 H, 2 CH, J = 7.6 Hz). 13C NMR, δ: 14.15, 44.61, 60.39,
61.56, 127.73 (Ph), 128.71 (Ph), 129.62 (Ph), 134.54, 134.82,
134.93, 135.49, 135.86 (Ph), 137.90, 138.67, 138.76, 139.41,
140.27, 141.57, 141.75, 141.97, 142.13, 142.39, 142.56, 142.93,
143.25, 143.32, 143.49, 143.72, 143.89, 144.05, 144.06, 144.88,
147.64, 167.30 (COOEt).
1´aꢀBenzylꢀ1´aꢀethoxycarbonylꢀ1´aꢀcarbaꢀ1´(2´)aꢀhomoꢀ
(C60ꢀIh)[5,6]fullerene (7b). 1H NMR, δ: 1.23 (t, 3 H, Me,
J = 7.2 Hz); 3.09 (s, 2 H, CH2); 4.32 (q, 2 H, CH2, J = 7.2 Hz);
7.24 (t, H, CH, J = 7.2 Hz); 7.32 (t, 2 H, 2 CH, J = 7.2 Hz); 7.35
(d, 2 H, 2 CH, J = 7.6 Hz). 13C NMR, δ: 14.32, 36.94, 62.32,
64.89, 127.55 (Ph), 128.46 (Ph), 130.01 (Ph), 136.91 (Ph),
135.49, 136.55, 137.07, 138.04, 138.27, 138.97, 139.29, 140.46,
141.54, 142.24, 142.30, 142.50, 142.97, 143.21, 143.25, 143.49,
143.51, 143.62, 143.70, 144.20, 144.60, 144.73, 145.14, 147.59,
171.25 (COOEt).
1
1730. UV, λmax/nm: 261, 327, 425. H NMR, δ: 1.53 (t, 3 H,
Me, J = 7.2 Hz); 1.58 (t, 3 H, Me, J = 7.2 Hz); 2.96 (q, 2 H,
CH2, J = 7.2 Hz); 4.54 (q, 2 H, CH2, J = 7.2 Hz). 13C NMR, δ:
11.63, 14.44, 23.18, 50.93, 62.13, 76.20 (sp3), 137.36, 137.79,
140.53, 140.79, 141.71, 141.84, 141.87, 141.92, 142.60, 142.66,
142.74, 142.87, 143.33, 143.53, 143.92, 144.23, 144.32, 144.47,
144.83, 144.85, 144.87, 144.90, 145.27, 145.81, 147.78, 166.75
(COOEt). MS, m/z: 834 [M]+.
1´aꢀEthylꢀ1´aꢀethoxycarbonylꢀ1´aꢀcarbaꢀ1´(2´)aꢀhomoꢀ
(C60ꢀIh)[5,6]fullerene (6a). IR, ν/cm–1: 520; 1200; 1220; 1730.
UV, λmax/nm: 262, 333. 1H NMR, δ: 1.35 (t, 3 H, Me, J = 7.2 Hz);
1.46 (t, 3 H, Me, J = 7.2 Hz); 3.89 (q, 2 H, CH2, J = 7.2 Hz);
4.25 (q, 2 H, CH2, J = 7.2 Hz). 13C NMR, δ: 10.58, 14.34, 32.18,
59.13, 61.40, 134.23, 134.85, 135.44, 137.73, 138.42, 138.70,
139.04, 139.99, 141.28, 141.88, 142.00, 142.07, 142.21, 142.65,
142.74, 142.80, 142.88, 142.94, 143.02, 143.19, 143.68, 144.04,
144.34, 144.96, 147.38 168.84 (COOEt).
1´ꢀIsobutylꢀ1´ꢀethoxycarbonylꢀ(C60ꢀIh)[2´,3´:1,9]cycloꢀ
propa[5,6]fullerene (5b). IR, ν/cm–1: 520; 1120; 1170; 1220;
1460; 1620; 1730. UV, λmax/nm: 260, 328, 425. 1H NMR, δ: 1.36
(d, 6 H, 2 Me, J = 6.4 Hz); 1.52 (t, 3 H, Me, J = 7.2 Hz);
2.25—2.31 (m, 1 H, CH); 2.84 (d, 2 H, CH2, J = 7.2 Hz); 4.52
(q, 2 H, CH2, J = 7.2 Hz). 13C NMR, δ: 14.88, 22.94, 28.03,
37.71, 49.27, 62.39, 75.88 (sp3), 137.65, 138.09, 140.92, 141.16,
142.09, 142.20, 142.27, 142.96, 143.02, 143.10, 143.22, 143.76,
143.94, 144.35, 144.59, 144.67, 144.69, 144.85, 145.22, 145.25,
145.27, 145.35, 145.52, 146.82, 148.08, 166.96 (COOEt). MS,
m/z: 862 [M]+.
1´ꢀ(1HꢀIndolꢀ3ꢀylmethyl)ꢀ1´ꢀethoxycarbonylꢀ(C60ꢀIh)ꢀ
[2´,3´:1,9]cyclopropa[5,6]fullerene (11). IR, ν/cm–1: 500; 710;
1180; 1410; 1440; 1620; 1720. UV, λmax/nm: 260, 329, 425.
1H NMR, δ: 1.28 (t, 3 H, Me, J = 7.2 Hz); 4.31 (q, 2 H, CH2,
J = 7.2 Hz); 4.39 (s, 2 H, CH2); 7.16 (t, H, CH, J = 6.8 Hz); 7.21
(d, H, CH, J = 6.0 Hz); 7.22 (d, H, CH, J = 6.0 Hz); 7.43 (d, H,
CH, J = 8.0 Hz); 7.55 (t, H, CH, J = 8.0 Hz); 9.81 (s, 1 H, NH).
13C NMR, δ: 14.49, 25.86, 50.83, 62.55, 76.61 (sp3), 111.30,
111.41, 119.00, 120.20, 122.93, 127.65, 133.07, 137.92, 138.25,
140.96, 141.26, 141.58, 142.09, 142.18, 142.25, 142.32, 143.01,
143.06, 143.15, 143.22, 143.29, 143.75, 143.93, 144.04, 144.35,
144.66, 144.73, 144.87, 145.23, 145.27, 145.59, 146.49, 147.80,
166.75 (COOEt). MS, m/z: 935 [M]+.
1´aꢀIsobutylꢀ1´aꢀethoxycarbonylꢀ1´aꢀcarbaꢀ1´(2´)aꢀhomoꢀ
(C60ꢀIh)[5,6]fullerene (6b). IR, ν/cm–1: 520; 740; 1120; 1200;
1
1430; 1460; 1620. UV, λmax/nm: 263, 330. H NMR, δ: 1.23
1´aꢀ(1HꢀIndolꢀ3ꢀylmethyl)ꢀ1´aꢀethoxycarbonylꢀ1´aꢀcarbaꢀ
(d, 6 H, 2 Me, J = 6.8 Hz); 1.36 (t, 3 H, Me, J = 7.2 Hz); 1.94—2.02
(m, 1 H, CH); 3.79 (d, 2 H, CH2, J = 7.2 Hz); 4.21 (q, 2 H, CH2,
J = 7.2 Hz). 13C NMR, δ: 14.59, 23.89, 27.71, 47.27, 57.81,
61.62, 134.51, 134.98, 135.14, 135.23, 137.91, 138.67, 138.75,
139.34, 140.27, 141.34, 141.76, 141.92, 142.17, 142.42, 142.61,
142.88, 143.17, 143.19, 143.46, 143.71, 143.86, 143.99, 144.03,
144.89, 147.64, 168.82 (COOEt).
1´(2´)aꢀhomo(C60ꢀIh)[5,6]fullerene (12). IR, ν/cm–1: 520; 1180;
1
1210; 1430; 1630; 1730. UV, λmax/nm: 263, 330. H NMR, δ:
1.03 (t, 3 H, CH3, J = 7.2 Hz); 3.87 (q, 2 H, CH2, J = 7.2 Hz);
5.35 (s, 2 H, CH2); 7.11 (t, H, CH, J = 6.8 Hz); 7.21 (d, H, CH,
J = 6.0 Hz); 7.37 (d, H, CH, J = 6.0 Hz); 7.43 (d, H, CH,
J = 8.0 Hz); 7.55 (t, H, CH, J = 8.0 Hz); 9.76 (s, H, NH).
13C NMR, δ: 14.05, 35.04, 61.73, 62.43, 111.59, 111.22, 118.82,
120.10, 122.69, 130.60, 135.20, 135.72, 135.93, 136.20, 137.92,
138.09, 138.75. 138.96, 139.42, 140.24, 141.58, 141.80, 141.95,
142.18, 142.32, 142.50, 142.56, 143.48, 143.60, 143.71, 143.88,
144.04, 144.87, 147.62, 167.83 (COOEt).
1´aꢀIsobutylꢀ1´aꢀethoxycarbonylꢀ1´aꢀcarbaꢀ1´(2´)aꢀhomoꢀ
1
(C60ꢀIh)[5,6]fullerene (7a). H NMR, δ: 1.05 (d, 6 H, 2 Me,
J = 6.4 Hz); 1.69 (t, 3 H, Me, J = 7.2 Hz); 1.75—1.81 (m, 1 H,
CH); 2.93 (d, 2 H, CH2, J = 7.2 Hz); 4.59 (q, 2 H, CH2, J = 7.2 Hz).
13C NMR, δ: 14.79, 23.89, 26.63, 46.18, 54.25, 62.13, 135.14,
135.23, 136.55, 137.21, 138.04, 140.46, 141.68, 142.17, 142.36,
142.45, 142.97, 143.17, 143.19, 143.46, 143.57, 143.71, 144.16,
144.54, 144.79, 145.23, 147.64.
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 07ꢀ03ꢀ00287)
and the Council on Grants of the President of the Rusꢀ

1730
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 8, August, 2009
Tuktarov et al.
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Received February 2, 2009