A facile access to [60]fullerene-fused 1,3-dioxolanes: Reaction of [60]fullerene with aldehydes/ketones promoted by ferric perchlorate

Article abstract of DOI:10.1021/ol101206u

(Figure Presented) The facile reaction of [60]fullerene (C₆₀) with various aldehydes or ketones in the presence of ferric perchlorate successfully afforded the rare C₆₀-fused 1,3-dioxolanes. A possible reaction mechanism for the formation of the C₆₀-fused 1,3-dioxolanes is proposed.

Full text of DOI:10.1021/ol101206u

ORGANIC
LETTERS
2010
Vol. 12, No. 14
3258-3261
A Facile Access to [60]Fullerene-Fused
1,3-Dioxolanes: Reaction of
[60]Fullerene with Aldehydes/Ketones
Promoted by Ferric Perchlorate
Fa-Bao Li, Tong-Xin Liu, Xun You, and Guan-Wu Wang*
Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory
of Soft Matter Chemistry, and Department of Chemistry, UniVersity of Science and
Technology of China, Hefei, Anhui 230026, People’s Republic of China
gwang@ustc.edu.cn
Received May 26, 2010
ABSTRACT
The facile reaction of [60]fullerene (C60) with various aldehydes or ketones in the presence of ferric perchlorate successfully afforded the rare
C60-fused 1,3-dioxolanes. A possible reaction mechanism for the formation of the C60-fused 1,3-dioxolanes is proposed.
Since the availability of fullerenes in a macroscopic amount,
various types of reactions for the functionalization of
fullerenes have been discovered, and numerous fullerene
products with wide structural diversities have been prepared.1
However, fullerene-fused 1,3-dioxolane derivatives2-4 have
been relatively rare until now. Elemes et al. reported the
synthesis of the first fullerene-fused 1,3-dioxolane as one of
the two products via the reaction of [60]fullerene (C60) with
dimethyldioxirane.2a Wang et al. described the preparation
of another C60-fused 1,3-dioxolane by the reaction of C60
with PhCH2ONa-PhCH2OH under aerobic conditions.2b It
should be noted that the latter methodology was only limited
to benzoxide as the reaction of C60 with other alkoxides gave
fullerene products with a C60-fused tetrahydrofuran ring
skeleton and an acetal moiety.5 The research groups of
Tajima3a and Gan3b realized the synthesis of C60-fused 1,3-
dioxolane derivatives from fullerene epoxides through the
reactions with aldehydes or acetone in the presence of a
Lewis acid. Two orthoester-type 1,3-dioxolanofullerenes
were also reported.4 Among the reported C60-fused 1,3-
dioxolane derivatives, only four were prepared directly from
C60.2,4 Therefore, it is still demanding to develop new
protocol to obtain C60-fused 1,3-dioxolane derivatives directly
from C60 in a straightforward and efficient way with a broad
substrate scope.
(1) For selected reviews, see: (a) Hirsch, A. Synthesis 1995, 895. (b)
Thilgen, C.; Diederich, F. Chem. ReV. 2006, 106, 5049. For some recent
papers, see: (c) Zhang, G.; Huang, S.; Xiao, Z.; Chen, Q.; Gan, L.; Wang,
Z. J. Am. Chem. Soc. 2008, 130, 12614. (d) Murata, M.; Maeda, S.;
Morinaka, Y.; Murata, Y.; Komatsu, K. J. Am. Chem. Soc. 2008, 130, 15800.
(e) Filippone, S.; Maroto, E. E.; Martin-Domenech, A.; Suarez, M.; Martin,
N. Nat. Chem. 2009, 1, 578. (f) Clavaguera, S.; Khan, S. I.; Rubin, Y. Org.
Lett. 2009, 11, 1389. (g) Wang, G.-W.; Lu, Y.-M.; Chen, Z.-X. Org. Lett.
2009, 11, 1507. (h) Tzirakis, M. D.; Orfanopoulos, M. J. Am. Chem. Soc.
2009, 131, 4063. (i) Li, C. Z.; Matsuo, Y.; Nakamura, E. J. Am. Chem.
Soc. 2009, 131, 17058.
(2) (a) Elemes, Y.; Silverman, S. K.; Sheu, C. M.; Kao, M.; Foote, C. S.;
Alvarez, M. M.; Whetten, R. L. Angew. Chem., Int. Ed. Engl. 1992, 31,
351. (b) Wang, G.-W.; Shu, L.-H.; Wu, S.-H.; Wu, H.-M.; Lao, X.-F.
J. Chem. Soc., Chem. Commun. 1995, 1071
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(3) (a) Shigemitsu, Y.; Kaneko, M.; Tajima, Y.; Takeuchi, K. Chem.
Lett. 2004, 33, 1604. (b) Yang, X.; Huang, S.; Jia, Z.; Xiao, Z.; Jiang, Z.;
Zhang, Q.; Gan, L.; Zheng, B.; Yuan, G.; Zhang, S. J. Org. Chem. 2008,
73, 2518
.
Recently, our group has been interested in reactions of
C60 mediated by metal salts such as Mn(OAc)3,6,7
(4) (a) Yoshida, M.; Morinaga, Y.; Iyoda, M.; Kikuchi, K.; Ikemodo,
I.; Achiba, Y. Tetrahedron Lett. 1993, 34, 7629. (b) Troshin, P. A.;
8
Peregudov, A. S.; Lyubovskaya, R. N. Tetrahedron Lett. 2006, 47, 2969
.
Cu(OAc)2,7c Pb(OAc)4,7h or Pd(OAc)2 to prepare a series
10.1021/ol101206u  2010 American Chemical Society
Published on Web 06/21/2010

of novel fullerene derivatives. We also reported the synthesis
of rare fullerooxazoles by the Fe(ClO4)3-mediated reaction
of C60 with a variety of nitriles,9 which is the first example
for the direct reaction of C60 with the unsaturated carbon-
nitrogen triple bond moiety of nitriles in the presence of
water. In continuation of our interest in Fe(ClO4)3-mediated
reactions of C60,9 herein we describe the Fe(ClO4)3-mediated
one-step reaction of C60 with aldehydes or ketones to afford
a variety of scarce C60-fused 1,3-dioxolane derivatives.
Table 1. Reaction Conditions and Yields for the Reaction of C60
with Aldehydes 1a-k in the Presence of Fe(ClO4)3·xH2Oa
In our previous study, we found that the direct dissolu-
tion10 of Fe(ClO4)3 by nitriles played a crucial role for the
successful synthesis of fullerooxazoles.9 Similarly, we
explored the Fe(ClO4)3-promoted reaction of C60 with various
aldehydes by adopting the direct dissolution method, i.e.,
Fe(ClO4)3 was first dissolved in a chosen aldehyde, and then
the dichlorobenzene (ODCB) solution of C60 was added.
Much to our satisfaction, we found that the Fe(ClO4)3-
mediated reaction of C60 with aldehydes 1a-k, that is,
benzaldehyde (1a), p-tolualdehyde (1b), 4-methoxybenzal-
dehyde (1c), 3,4-dimethylbenzaldehyde (1d), 4-chloroben-
zaldehyde (1e), 2-chlorobenzaldehyde (1f), p-phthalaldehyde
(1g), 4-nitrobenzaldehyde (1h), 4-cyanobenzaldehyde (1i),
cinnamaldehyde (1j), and propionaldehyde (1k), afforded
C60-fused 1,3-dioxolane derivatives 2a-k.
Initially, the Fe(ClO4)3-promoted reaction of C60 with 1a
was chosen to screen the reaction conditions. The details
are listed in Table S1 in the Supporting Information.
Screening experiments indicated that the best molar ratio of
C60:Fe(ClO4)3·xH2O:1a was 1:2:5, and the reaction temper-
ature was 80 °C. These optimized reaction conditions could
be extended to other aldehydes except that higher temperature
was required for the melting of 1g-i and subsequent
dissolution of Fe(ClO4)3, and more propionaldehyde was
demanded due to its lower boiling point and thus easier
evaporation. The reaction conditions and yields for the
Fe(ClO4)3-mediated reaction of C60 with aldehydes 1a-k are
summarized in Table 1. The progress of the reactions should
be carefully monitored by TLC to prevent overreaction.
As can be seen from Table 1, aromatic aldehydes bearing
either electron-donating or electron-withdrawing groups
(1a-i), cinnamaldehyde (1j), as well as aliphatic aldehyde
(1k) could be successfully employed to prepare the C60-fused
1,3-dioxolane derivatives in 14-38% yields (30-91% based
on consumed C60). For the synthesis of compound 2a, the
a All reactions were performed under protection of nitrogen with a molar
ratio of C60:Fe(ClO4)3·xH2O:1 ) 1:2:5 unless otherwise indicated. b Molar
ratio of C60:Fe(ClO4)3·xH2O:1k ) 1:2:50. c Isolated yield; the number in
parentheses was based on consumed C60.
(5) Wang, G.-W.; Lu, Y.-M.; Chen, Z.-X.; Wu, S.-H. J. Org. Chem.
2009, 74, 4841.
(6) For a review, see: Wang, G.-W.; Li, F.-B. J. Nanosci. Nanotechnol.
2007, 7, 1162.
(7) (a) Zhang, T.-H.; Lu, P.; Wang, F.; Wang, G.-W. Org. Biomol. Chem.
2003, 1, 4403. (b) Wang, G.-W.; Zhang, T.-H.; Cheng, X.; Wang, F. Org.
Biomol. Chem. 2004, 2, 1160. (c) Wang, G.-W.; Li, F.-B. Org. Biomol.
Chem. 2005, 3, 794. (d) Chen, Z.-X.; Wang, G.-W. J. Org. Chem. 2005,
70, 2380. (e) Cheng, X.; Wang, G.-W.; Murata, Y.; Komatsu, K. Chin.
Chem. Lett. 2005, 16, 1327. (f) Wang, G.-W.; Yang, H.-T.; Miao, C.-B.;
Xu, Y.; Liu, F. Org. Biomol. Chem. 2006, 4, 2595. (g) Wang, G.-W.; Li,
F.-B.; Zhang, T.-H. Org. Lett. 2006, 8, 1355. (h) Li, F.-B.; Liu, T.-X.;
Huang, Y.-S.; Wang, G.-W. J. Org. Chem. 2009, 74, 7743.
(8) (a) Zhu, B.; Wang, G.-W. J. Org. Chem. 2009, 74, 4426. (b) Zhu,
B.; Wang, G.-W. Org. Lett. 2009, 11, 4334.
current Fe(ClO4)3-mediated reaction of C60 with benzalde-
hyde is preferable to the reaction of C60 with PhCH2ONa-
PhCH2OH, which generated product 2a in 15% yield (68%
based on consumed C60).2b The cyano group is known to
react with C60 in the presence of Fe(ClO4)3.9 Nevertheless,
no corresponding fullerooxazole could be identified from the
Fe(ClO4)3-mediated reaction of C60 with substrate 1i, dem-
onstrating the superior reactivity of the aldehyde group over
the cyano group.
(9) Li, F.-B.; Liu, T.-X.; Wang, G.-W. J. Org. Chem. 2008, 73, 6417.
(10) The term “melting” in ref 9 should be better expressed as
“dissolution”.
Org. Lett., Vol. 12, No. 14, 2010
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Product 2a2b,3a is a known compound, and its identity was
confirmed by comparison of its spectral data with those
reported in the literature. New compounds 2b-k were
Table 2. Reaction Conditions and Yields for the Reaction of C60
with Ketones 3a-j in the Presence of Fe(ClO4)3·xH2Oa
unambiguously characterized by their HRMS, 1H NMR, 13
C
NMR, FT-IR, and UV-vis spectra. In the1H NMR spectra
of compounds 2b-k, the methine proton on the heterocycle
ring appeared in very downfield region (6.3-7.6 ppm). In
their 13C NMR spectra, the observation of no more than 30
lines for the sp2-carbons of the C60 skeleton was consistent
with their Cs molecular symmetry, and the signals for the
sp3-carbons of the acetal and fullerene moiety were located
at 99.2-104.1 and 93.5-94.6 ppm, close to those of reported
C60-fused 1,3-dioxolane derivatives in the previous litera-
ture.2,3
To expand the scope of the reaction, the substrates were
extended from aldehydes to ketones. Acetophenone (3a),
4-methylacetophenone (3b), 4-methoxyacetophenone (3c),
4-chloroacetophenone (3d), 4-nitroacetophenone (3e), ben-
zophenone (3f), 9-fluorenone (3g), cyclopentanone (3h),
acetone (3i), and 5-methyl-2-hexanone (3j) were chosen to
react with C60 in the presence of Fe(ClO4)3 by the direct
dissolution method, and were found to generate C60-fused
1,3-dioxolane derivatives 4a-j.
The reaction conditions and yields for the Fe(ClO4)3-
mediated reaction of C60 with ketones 3a-j are summarized
in Table 2.
As can be seen from Table 2, both aromatic ketones
(3a-g) and aliphatic ketones (3h-j) could be successfully
utilized to prepare the C60-fused 1,3-dioxolane derivatives
4a-j in 9-29% yields (24-68% based on consumed C60).
The acyclic aromatic ketones (3a-f) gave reasonably good
isolated yields except 4-nitroacetophenone (3e), which af-
forded some byproducts. 9-Fluorenone also generated low
yield probably due to the steric interactions from the two
hydrogens at the C1 and C8 positions in the rigid ring system.
Aliphatic ketones (3h-j) generally afforded good product
yields. The isolated yield of C60-fused 1,3-dioxolane deriva-
tive 4i by our current protocol (18%, 44% based on
consumed C60) was much higher than that by the previously
reported procedure (5%, 7% based on consumed C60).2a
The structures of C60-fused dioxolanes 4a-j were fully
1
established by HRMS, H NMR, 13C NMR, FT-IR, and
UV-vis spectra. In their 13C NMR spectra, dioxolanes 4a-e
together with 4j showed similar spectral patterns with those
from aldehydes 1a-k. No more than 29 peaks including
some overlapped ones due to the 58 sp2-carbons of the
fullerene moiety were observed in the range of 137.3-149.4
ppm, consistent with the Cs symmetry of the molecular
structures, and the peaks for the two sp3-carbons of the C60
cage and ketal carbon appeared at 94.4-95.1 and 110.6-113.8
ppm. However, the remaining dioxolanes 4f-i exhibited
different spectral patterns with the above-mentioned diox-
olanes. The observation of only 14-16 lines for the sp2-
carbons of the C60 skeleton agreed well with the C2V
molecular symmetry, and the two sp3-carbons and ketal
carbon were located at 93.5-95.6 and 111.7-120.7 ppm.
Interestingly, the chemical shifts for the ketal carbons
(110.6-120.7 ppm) in the dioxolanes 4a-j were shifted
a All reactions were performed at 80 °C under protection of nitrogen.
b Molar ratio refers to C60:Fe(ClO4)3·xH2O:3. c Isolated yield; the number
in parentheses was based on consumed C60.
downfield about 11-17 ppm from those of the acetal carbons
in the dioxolanes 2b-k (99.2-104.1 ppm). In addition, the
identity of 4i was further confirmed by comparison of its
spectral data with those reported previously.2a
We previously reported that the reaction of methyl ketones
with C60 promoted by Mn(OAc)3/Cu(OAc)2 gave C60-fused
dihydrofurans and/or methanofullerenes.7c However, no
evidence for the formation of C60-fused dihydrofuran and/
3260
Org. Lett., Vol. 12, No. 14, 2010

Scheme 1. Proposed Reaction Mechanism for the Formation of
Scheme 2. Reaction of C60-Fused Dioxolane 2a with
Chlorobenzene and 1,2-Dichlorobenzene in the Presence of
Aluminum Chloride
C60-Fused 1,3-Dioxolanes
(Scheme 2). Tajima et al.12 reported the BF3·Et2O-assisted
nucleophilic substitution of C60O. They found that the
progress of the reaction depended considerably on the
nucleophilicity of the aromatic compound, and chlorobenzene
failed to react with C60O. Even though the reaction mech-
anism for the formation of fullerenols 8 is not quite clear
now, the reaction should occur via a carbocationic intermedi-
ate generated with the assistance of AlCl3. It is intriguing
that electron-deficient chlorobenzene and 1,2-dichloroben-
zene could react in our case.
In summary, the synthesis of scarce C60-fused 1,3-
dioxolanes has been achieved by the Fe(ClO4)3-promoted
reaction of C60 with aldehydes or ketones. It is noteworthy
that functional groups such as Cl, CHO, NO2, and CN could
be tolerated under our reaction conditions and can be further
transformed to other moieties. The current one-step approach
to the preparation of C60-fused 1,3-dioxolanes from cheap
and easily accessible aldehydes/ketones and Fe(ClO4)3 was
obviously more straightforward and practical than the previ-
ous protocols.2,3a The direct dissolution of aldehydes/ketones
and Fe(ClO4)3 proved to be crucial for the efficient synthesis
of C60-fused 1,3-dioxolanes. A plausible reaction mechanism
for the formation of C60-fused 1,3-dioxolanes is suggested.
or methanofullerene could be obtained from the current
Fe(ClO4)3-mediated reaction of C60 with methyl ketones.
Obviously, different reaction mechanisms are operating for
the reaction of C60 with methyl ketones mediated by
Fe(ClO4)3 and Mn(OAc)3/Cu(OAc)2. On the basis of the
previously suggested mechanism for the reaction of C60 with
various nitriles in the presence of Fe(ClO4)3 to afford the
fullerooxazoles,9 we propose a possible mechanism for the
formation of C60-fused 1,3-dioxolanes 2/4 from the Fe-
(ClO4)3-mediated reaction of C60 with aldehydes/ketones, as
shown in Scheme 1. A chosen aldehyde or ketone reacts with
the hydrated H2O in Fe(ClO4)3·xH2O to produce Fe(III)-
complex 5 accompanied by the loss of HClO4. The observed
reddening of the mixtures of aldehydes/ketones and
Fe(ClO4)3·xH2O hints the formation of complexes between
Fe(ClO4)3·xH2O and aldehydes/ketones.11 Homolytical ad-
dition of 5 to C60 generates fullerenyl radical 6 with an
elimination of Fe(ClO4)2·(x-1)H2O, and then coordination
with another molecule of Fe(ClO4)3·xH2O to form Fe(III)-
complex 7, which undergoes intramolecular cyclization with
the loss of a Fe(II) species to afford C60-fused 1,3-dioxolanes
2/4.
Acknowledgment. The authors are grateful for the finan-
cial support from the National Natural Science Foundation
of China (No. 20972145), the Specialized Research Fund
for the Doctoral Program of Higher Education (No.
200803580019), and the National Basic Research Program
of China (2006CB922003).
The C60-fused 1,3-dioxolane derivatives can be valuable
precursors for further functionalization. Preliminary results
showed that treatment of C60-fused 1,3-dioxolane derivative
2a with AlCl3 in chlorobenzene and 1,2-dichlorobenzene at
90 °C afforded 4-chlorophenyl- and 3,4-dichlorophenyl-
substituted fullerenols in 35% and 14% yield, respectively
Supporting Information Available: Experimental pro-
cedures, optimization results, and characterization data, as
well as the 1H NMR and 13C NMR spectra of products 2a-k,
4a-j, and 8b. This material is available free of charge via
the Internet at http://pubs.acs.org.
(11) Citterio, A.; Sebastiano, R.; Carvayal, M. C. J. Org. Chem. 1991,
56, 5335.
(12) Tajima, Y.; Hara, T.; Honma, T.; Matsumoto, S.; Takeuchi, K. Org.
Lett. 2006, 8, 3203.
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