Bismalonates constructed on a hexaphenylbenzene scaffold for the synthesis of equatorial fullerene bisadducts

Article abstract of DOI:10.1002/ejoc.200900290

Hexaphenylbenzene derivatives bearing two aldehyde groups were prepared by reaction of 4,4′-(ethyne-l,2-diyl)dibenzaldehyde with bisarylalkynes in the presence of a catalytic amount of Co₂(CO)₈. These synthetic intermediates were use

Full text of DOI:10.1002/ejoc.200900290

FULL PAPER
DOI: 10.1002/ejoc.200900290
Bismalonates Constructed on a Hexaphenylbenzene Scaffold for the Synthesis
of Equatorial Fullerene Bisadducts
Teresa M. Figueira-Duarte,[a] Aline Gégout,[a] Jean Olivier,[a] François Cardinali,[a] and
Jean-François Nierengarten*[a]
Keywords: Conjugation / Cyclotrimerization / Fullerenes / Macrocycles / Structure elucidation
Hexaphenylbenzene derivatives bearing two aldehyde
groups were prepared by reaction of 4,4Ј-(ethyne-1,2-diyl)di-
benzaldehyde with bisarylalkynes in the presence of a cata-
lytic amount of Co2(CO)8. These synthetic intermediates
were used to produce the corresponding bismalonates. Fi-
nally, macrocyclization of the bismalonates with C60 afforded
equatorial fullerene bisadducts. The relative position of the
two cyclopropane rings on the C60 core was determined on
the basis of the molecular symmetry (C1) deduced from the
1H and 13C NMR spectra and further confirmed by the char-
acteristic features seen in their UV/Vis spectra.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2009)
vation of the lowest singlet excited state of the conjugated
system occurs by OPVǞC60 singlet–singlet energy transfer,
thus populating the lowest fullerene singlet excited state. As
the latter possesses a larger cross-section than the ground
state, it is itself involved in the nonlinear behavior. For this
reason, the combination of a MPA chromophore with C60
leads to improved optical limiting properties. In this paper,
we now report in detail the synthesis of this fullerene bis-
adduct as well as our efforts to unambiguously assign its
regiochemistry.
Introduction
The use of C60 as an energy and/or electron acceptor in
photochemical molecular devices has generated tremendous
research efforts in the past few years.[1] In particular, the
carbon sphere has been combined with π-conjugated oligo-
mers for the construction of donor-fullerene arrays.[2] Such
hybrid compounds have shown excited-state interactions
making them excellent candidates for fundamental photo-
physical studies.[2] Furthermore, C60–(π-conjugated oligo-
mer) dyads have been used as the active layer in organic
photovoltaic cells.[3] Fullerene derivatives have also shown
great potential for optical-limiting applications.[4] Effec-
tively, the transmission of fullerene solutions decreases by
increasing the light intensity. For short pulses (ps), the limit-
ing action is ascribed to pure reverse saturable absorption
(RSA), whereas for longer pulses (ns–µs) additional mecha-
nisms of mainly thermal origin are invoked.[5] Several stra-
tegies have been developed to improve the optical limiting
properties of fullerene derivatives.[6,7] One is the preparation
of hybrid compounds combining the fullerene with an ex-
cited-state multiphoton absorption (MPA) chromophore.[7]
As part of this research, we have reported a preliminary
communication on the excited-state properties of com-
pound 1 assembling C60 with a branched oligophenylenevi-
nylene (OPV)-based MPA chromophore.[7] Interestingly,
compound 1 shows enhanced optical-limiting properties
when compared to a 1:1 mixture of the separated compo-
nents. When the two moieties are covalently linked, deacti-
Results and Discussion
The preparation of the functionalized hexaphenylben-
zene core required for the synthesis of compound 1 is based
on a metal-catalyzed cyclotrimerization[8] involving two dif-
ferent bisarylalkynes. The synthesis of alkyne building
[a] Laboratoire de Chimie des Matériaux Moléculaires, Université
de Strasbourg et CNRS (UMR 7509), Ecole Européenne de
Chimie, Polymères et Matériaux (ECPM),
25 rue Becquerel, 67087 Strasbourg Cedex 2, France
E-mail: nierengarten@chimie.u-strasbg.fr
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T. M. Figueira-Duarte, A. Gégout, J. Olivier, F. Cardinali, J.-F. Nierengarten
FULL PAPER
block 7 is depicted in Scheme 1. Reduction of ester 2[9] with temperature for 17 h afforded 8 in 78% yield. The 1H NMR
LiAlH4 gave benzylic alcohol 3 in 94% yield. Bromination spectrum of 8 is quite simple and shows that all the six
of 3 by using trimethylsilyl bromide (TMSBr) followed by peripheral stilbene subunits are equivalent. Further conclu-
treatment of resulting bromide 4 with P(OEt)3 under Arbu- sive evidence for the formation of the homotrimer came
zov conditions afforded 5 in an overall 80% yield. Reaction from the comparison of the 13C NMR spectra of 7 and 8.
of 5 with bisaldehyde 6[10] under Wadsworth–Emmons con- In particular, the characteristic signal corresponding to the
ditions gave compound 7 in 77% yield. All the spectro- sp C atom detected at 90.5 ppm for compound 7 is not any-
scopic studies and elemental analysis results were consistent more present for 8, whereas an additional resonance is de-
with the structure of 7. In particular, the coupling constant tected at 140.1 ppm in the spectrum of 8. The latter signal
of ca. 17 Hz for the AB system corresponding to the signal is attributed to the six equivalent sp2 C atoms of the central
1
of the vinylic protons in the H NMR spectrum confirmed phenyl core of 8. The structure of 8 was also confirmed
the E stereochemistry of the two equivalent double bonds by MALDI-TOF mass spectrometry showing the expected
in 7.
molecular ion peak at m/z = 4463 [M + H]+ (calcd. for
C
306H499O18 4462.81).
The reaction conditions developed for the preparation of
8 from building block 7 were adapted for the preparation
of 9 starting from alkynes 6 and 7. Treatment of 6 (1 equiv.)
and 7 (2 equiv.) with a catalytic amount of Co2(CO)8 in
dioxane at room temperature for 24 h gave a mixture of
hetero- and homotrimers from which targeted heterotrimer
9 was isolated by column chromatography. Compound 9
was thus obtained in 53% yield. It is worth noting that the
choice of the appropriate pairs of alkyne building blocks
for the preparation of a heterotrimer such as 9 was the key
to this synthesis. Actually, both alkyne precursors must
have a similar reactivity towards the catalyst. Indeed, the
first reactions were attempted from 7 and the bisalcohol
derived from bisaldehyde 6. Reaction of 7 with this diol in
Scheme 1. Reagents and conditions: (a) LiAlH4, THF, 0 °C, 3 h
(94%); (b) TMSBr, CHCl3, 0 °C to room temperature, 4 h (99%);
(c) P(OEt)3, 150 °C, 4 h (81%); (d) tBuOK, THF, 0 °C, 4 h (77%);
(e) Co2(CO)8, dioxane, room temperature, 17 h (78%).
The reaction conditions for the cyclotrimerization were
first optimized with compound 7. We found that Co2(CO)8
is an efficient catalyst[8,11] for the preparation of compound
8 from alkyne 7. Under optimized conditions, treatment of
Scheme 2. Reagents and conditions: (a) Co2(CO)8, dioxane, room
temperature, 24 h (53%); (b) LiAlH4, THF, 0 °C, 4 h (76%); (c)
DCC, DMAP, CH2Cl2, 0 °C to room temperature, 29 h (75%); (d)
7 with a catalytic amount of Co2(CO)8 in dioxane at room C60, DBU, I2, PhMe, room temperature, 3 h (32%).
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Synthesis of Equatorial Fullerene Bisadducts
the presence of a catalytic amount of Co2(CO)8 yielded usually confirmed by UV/Vis spectroscopy. Effectively, the
mainly the two homotrimers; no heterotrimers could be de- absorption spectra of C60 bisadducts are highly dependent
tected in the reaction mixture. The latter result is due to on the addition pattern and characteristic for each of the
the difference in reactivity between the two alkyne building regioisomers.[13,15] In the case of 1, however, the strong ab-
blocks under these conditions. Effectively, by following the sorption of the π-conjugated chromophore in the 300–
reaction by TLC, it appeared that compound 7 was con- 450 nm region partially covers the characteristic features of
sumed much faster than the other alkyne derivative the fullerene bisadduct moiety, which thus prevents unam-
(Scheme 2).
biguous structural assignment. This prompted us to prepare
Reduction of dialdehyde 9 with LiAlH4 in THF gave 10 model compound 17 with a simpler hexaphenylbenzene
in 76% yield. Reaction of diol 10 with carboxylic acid 11[12] bridging unit (Scheme 3).
under esterification conditions with the use of N,NЈ-dicyclo-
Reaction of 6 (1 equiv.) and 13 (2 equiv.) with a catalytic
hexylcarbodiimide (DCC) and 4-dimethylaminopyridine amount of Co2(CO)8 in dioxane at room temperature for
(DMAP) in CH2Cl2 afforded compound 12 in 75% yield. 12 h gave compound 14 in 49% yield. Reduction of dialde-
Fullerene derivative 1 was then prepared by taking advan- hyde 14 with LiAlH4 followed by treatment of resulting 15
tage of the versatile regioselective reaction developed in the with acid 11 in the presence of DCC and DMAP afforded
group of Diederich,[13] which led to macrocyclic bisadducts bismalonate 16. Compound 17 was then obtained in 25%
of C60 by a cyclization reaction at the C sphere with bisma- yield by reaction of 16 with C60, I2, and DBU in toluene
lonate derivatives in a double Bingel[14] cyclopropanation. at room temperature. The structure of compound 17 was
1
Reaction of 12 with C60, I2, and DBU in toluene at room confirmed by H and 13C NMR spectroscopy, mass spec-
1
temperature afforded the corresponding cyclization product trometry, and elemental analysis. The H NMR spectrum
1
1. Fullerene derivative 1 was characterized by H and 13C of 17 is depicted in Figure 1. In addition to the signals cor-
NMR, UV/Vis, and IR spectroscopy. In addition, its struc- responding to the hexaphenylbenzene bridging moiety, the
ture was confirmed by MALDI-TOF mass spectrometry, spectrum is characterized by four sets of AB quartets for
showing the expected molecular ion peak at m/z = 5021 the four different diastereotopic benzylic CH2 groups and
[M]+ (calcd. for C348H454O24 5021.42). The molecular sym- two AX2 systems for the aromatic protons of the two non-
1
metry (C1) deduced from the H and 13C NMR spectra of equivalent peripheral didodecyloxyphenyl moieties. As ob-
1 suggests that this bisadduct could be the equatorial re- served for compound 1, NMR spectroscopy shows that
gioisomer. This is also consistent with molecular modeling compound 17 is C1 symmetric. The absorption spectrum of
studies. For fullerene derivatives bearing two malonate ad- bisadduct 17 reveals two distinct bands (λmax = 252 and
dends, the relative position of the two cyclopropane rings 320 nm) in the UV region. In the visible spectral region, the
on the C60 core suggested by the molecular symmetry is spectrum is broad with two shoulders (395 and 408 nm),
Scheme 3. Reagents and conditions: (a) Co2(CO)8, dioxane, room temperature, 12 h (49%); (b) LiAlH4, THF, 0 °C, 3 h (68%); (c) 11,
DCC, DMAP, CH2Cl2, 0 °C to room temperature, 26 h (53%); (d) C60, DBU, I2, PhMe, room temperature, 12 h (25%).
Eur. J. Org. Chem. 2009, 3879–3884
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T. M. Figueira-Duarte, A. Gégout, J. Olivier, F. Cardinali, J.-F. Nierengarten
FULL PAPER
out with a Bruker BIFLEXTM matrix-assisted laser desorption
and the band corresponding to the lowest-allowed singlet
transition, which is very sharp and well distinguishable for
C60,[16] is barely detectable at ca. 420 nm. Importantly, the
UV/Vis spectrum of 17 clearly shows the characteristic
features previously reported for analogous equatorial bis-
adducts[13,15] and unambiguously confirms the addition
time-of-flight mass spectrometer equipped with SCOUTTM high-
resolution optics, an X-Y multisample probe, and a gridless reflec-
tor. Ionization was accomplished with the 337 nm beam from a
nitrogen laser with a repetition rate of 3 Hz. All data were acquired
at a maximum accelerating potential of 20 kV in the linear positive
ion mode. The output signal from the detector was digitized at a
sampling rate of 1 GHz. A saturated solution of 1,8,9-trihydroxy-
anthracene (dithranol Aldrich EC: 214-538-0) in CH2Cl2 was used
as a matrix. Typically, a 1:1 mixture of the sample solution in
CH2Cl2 was mixed with the matrix solution and 0.5 µL of the re-
sulting mixture was deposited on the probe tip. Elemental analyses
were performed by the analytical service at the Institut Charles
Sadron, Strasbourg.
1
pattern deduced from the H and 13C NMR spectra.
Compound 3: A 1  LiAlH4 solution in THF (4.5 mL, 4.5 mmol)
was added dropwise to a stirred solution of 2 (4.00 g, 5.81 mmol)
in dry THF (30 mL) at 0 °C. The resulting mixture was stirred for
3 h at 0 °C, then MeOH was carefully added. The resulting mixture
was filtered (Celite) and evaporated to yield 3 (3.62 g, 94%) as a
colorless solid. 1H NMR (300 MHz, CDCl3): δ = 0.89 (t, J =
6.5 Hz, 9 H, CH3), 1.20–1.80 (m, 60 H, CH2), 3.95 (m, 9 H, OCH2),
4.59 (s, 2 H, ArCH2), 6.56 (s, 2 H, Ar-H) ppm. C43H80O4 (661.11):
calcd. C 78.12, H 12.20; found C 78.34, H 12.41.
1
Figure 1. H NMR spectrum (300 MHz, CDCl3) of compound 17
Compound 4: TMSBr (0.9 mL, 6.56 mmol) was added dropwise to
a stirred solution of 3 (3.62 g, 5.46 mmol) in CHCl3 (25 mL) at
0 °C. The resulting solution was stirred for 1 h at 0 °C, then 3 h at
room temperature. The resulting mixture was evaporated to yield 4
(3.90 g, 5.39 mmol, 99%) as a colorless solid. 1H NMR (300 MHz,
CDCl3): δ = 0.88 (m, 9 H, CH3), 1.2–1.8 (m, 60 H, CH2), 3.95
(m, 9 H, OCH2), 4.43 (s, 2 H, CH2Br), 6.57 (s, 2 H, Ar-H) ppm.
C43H79BrO3 (724.00): calcd. C 71.34, H 11.00; found C 71.45, H
10.98.
(* = CH2Cl2 impurity).
Conclusions
Hexaphenylbenzene derivatives 9 and 14 substituted with
two aldehyde groups were easily obtained by reaction of
bisaldehyde 6 with bisarylalkynes 8 and 13, respectively, in
the presence of a catalytic amount of Co2(CO)8. These pre-
Compound 5: A mixture of P(OEt)3 (0.92 mL, 5.39 mmol) and 4
cursors were used to produce the corresponding bismalon- (3.90 g, 5.39 mmol) was heated at 150 °C for 4 h. After cooling to
room temperature, the mixture was dried under high vacuum. Col-
umn chromatography (SiO2; CH2Cl2/MeOH, 99:1) yielded
ates 10 and 14. Finally, equatorial fullerene bisadducts 1
and 17 were prepared by the direct macrocyclization of 10
and 14, respectively, with the C60 sphere. The construction
of fullerene derivative 1 already illustrates the advantage of
the molecular design reported in this paper: multiple
derivatizations can be easily performed on the hexaphenyl-
benzene bridging unit. Indeed, the easy access to function-
alized hexaphenylbenzene derivatives should find multiple
applications in supramolecular devices, which rely on con-
trol of geometry for the expression of function.
5
1
(3.40 g, 81%) as a pale yellow oil. H NMR (300 MHz, CDCl3): δ
= 0.88 (m, 9 H, CH3), 1.20–1.80 (m, 66 H, CH2), 3.04 (d, JP,H
=
21 Hz, 2 H, CH2-P), 3.94 (m, 10 H, OCH2), 6.49 (d, JP,H = 3 Hz,
2 H, Ar-H) ppm. C47H89O6P (781.19): calcd. C 72.26, H 11.48;
found C 72.36, H 11.59.
Compound 7: A mixture of 6 (423 mg, 1.81 mmol), tBuOK (447 mg,
3.98 mmol), and 5 (3.39 g, 4.34 mmol) in dry THF (30 mL) was
stirred at 0 °C for 4 h. A saturated aqueous NH4Cl solution was
then added, and the THF evaporated. The aqueous layer was ex-
tracted twice with CH2Cl2. The combined organic layers were
washed with water, dried (MgSO4), and filtered, and the solvent
was then evaporated to dryness. Column chromatography (SiO2;
hexane/CH2Cl2, 1:1) gave 7 (2.08 g, 77%) as a pale yellow solid.
M.p. 85 °C. UV/Vis (CH2Cl2): λ (ε, Lmol–1 cm–1) = 229 (37600),
Experimental Section
General: Reagents and solvents were purchased as reagent grade
and used without further purification. Compounds 2,[9] 6,[10] 11,[12]
and 13[10] were prepared according to the literature. THF and diox-
ane were distilled from sodium benzophenone ketyl. All reactions
were performed in standard glassware under an inert Ar atmo-
sphere. Evaporation and concentration were done at water aspira-
tor pressure and drying in vacuo at 10–2 Torr. Column chromatog-
raphy was performed with silica gel 60 (230–400 mesh, 0.040–
0.063 mm) purchased from E. Merck. Thin-layer chromatography
(TLC) was performed on glass sheets coated with silica gel 60 F254
purchased from E. Merck with visualization by UV light. IR spec-
tra were measured with an ATI Mattson Genesis Series FTIR in-
strument. NMR spectra were recorded with a Bruker AC 300 with
solvent peaks as reference. MALDI-TOF mass spectra were carried
1
372 (92000) nm. H NMR (300 MHz, CDCl3): δ = 0.86 (m, 18 H,
CH3), 1.20–1.60 (m, 108 H, CH2), 1.80 (m, 12 H, CH2), 4.00 (m,
12 H, OCH2), 6.72 (s, 4 H, Ar-H), 7.00 (AB, J = 17 Hz, 4 H,
CH=CH), 7.47 (d, J = 7 Hz, 4 H, Ar-H), 7.51 (d, J = 7 Hz, 4 H,
Ar-H) ppm. 13C NMR (50 MHz, CDCl3): δ = 14.1, 22.7, 26.1, 29.4,
29.6, 29.7, 30.4, 31.9, 69.2, 73.6, 90.5, 105.3, 122.1, 126.3, 129.8,
131.9, 132.2, 137.4, 138.6, 153.3 ppm. C102H166O6 (1488.44): calcd.
C 82.31, H 11.24; found C 82.32, H 11.32.
Compound 8: A mixture of Co2(CO)8 (5 mg, 0.015 mmol) and 7
(200 mg, 0.134 mmol) in dry dioxane (5 mL) was stirred at room
temperature for 17 h, and the solvent was then evaporated. Column
chromatography (SiO2; CH2Cl2/hexane, 1:1) yielded 7 (156 mg,
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Synthesis of Equatorial Fullerene Bisadducts
78%) as a yellow solid. M.p. 274 °C. UV/Vis (CH2Cl2): λ (ε,
SiO2 (toluene then CH2Cl2), and the solvent was then evaporated.
Column chromatography (SiO2; hexane/CH2Cl2, 7:3) followed by
1
Lmol–1 cm–1) = 338 (172000) nm. H NMR (300 MHz, CDCl3): δ
= 0.88 (m, 54 H, CH3), 1.10–1.60 (m, 324 H, CH2), 3.94 (m, 36 H, gel permeation chromatography (Biorad, Biobeads SX-1, CH2Cl2)
OCH2), 6.59 (s, 12 H, Ar-H), 6.79 (m, 24 H, CH=CH and Ar-H), yielded 1 (155 mg, 32%) as a dark brown glassy product. IR
7.00 (d, J = 7 Hz, 12 H, Ar-H) ppm. 13C NMR (50 MHz, CDCl3):
δ = 14.1, 22.7, 26.1, 29.3, 29.4, 29.7, 30.3, 31.9, 69.1, 73.4, 76.4,
105.0, 125.0, 127.7, 128.0, 131.7, 132.6, 134.1, 138.1, 139.8, 140.1,
(CH2Cl2):
ν
=
=
1749 (C=O) cm–1. UV/Vis (CH2Cl2):
228 (295900), 328 (196750) nm. 1H NMR
λ (ε,
˜
Lmol–1 cm–1)
(300 MHz, CDCl3): δ = 0.88 (m, 48 H, CH3), 1.10–1.60 (m, 288 H,
153.2 ppm. MS (MALDI-TOF): m/z = 4463 [M +H]+. C306H498O18 CH2), 1.75 (m, 32 H, CH2), 3.93 (m, 32 H, OCH2), 4.90 (d, J =
(4465.31): calcd. C 82.31, H 11.24; found C 82.25, H 11.23.
12 Hz, 1 H, Ar-CH), 5.10 (d, J = 12 Hz, 1 H, Ar-CH), 5.34 (d, J
= 12 Hz, 1 H, Ar-CH), 5.40 (s, 2 H, Ar-CH2), 5.50 (d, J = 12 Hz,
1 H, Ar-CH), 5.60 (d, J = 12 Hz, 1 H, Ar-CH), 5.65 (d, J = 12 Hz,
1 H, Ar-CH), 6.3–7.1 (m, 46 H, Ar-H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 14.0, 14.1, 22.6, 26.0, 26.1, 29.2, 29.3, 29.35, 29.4,
29.45, 29.5, 29.6, 29.7, 30.3, 31.9, 68.1, 69.1, 73.4, 101.7, 105.1,
105.15, 106.9, 124.9, 127.6, 128.0, 128.1, 131.0, 131.2, 131.4, 131.6,
131.9, 132.0, 132.5, 134.1, 136.4, 136.5, 138.2, 138.3, 138.5, 139.1,
139.3, 139.4, 139.6, 140.2, 140.3, 140.6, 141.4, 141.6, 141.9, 142.1,
142.6, 142.7, 142.9, 142.95, 143.3, 143.4, 143.5, 143.6, 143.7, 143.8,
144.0, 144.1, 144.2, 144.4, 144.6, 144.7, 144.8, 144.9, 145.0, 145.2,
145.5, 145.7, 146.0, 146.1, 146.3, 146.4, 146.9, 147.2, 148.5, 153.2,
153.5, 160.4, 163.0, 163.1, 163.3, 163.4 ppm. MS (MALDI-TOF):
m/z = 5021 [M]+. C348H454O24 (5021.42): calcd. C 83.24, H 9.11;
found C 82.99, H 9.41.
Compounds 8 and 9: A mixture of Co2(CO)8 (21 mg, 0.061 mmol),
6 (111 mg, 0.47 mmol), and 7 (1.35 g, 0.91 mmol) in dry dioxane
(25 mL) was stirred at room temperature for 24 h, and the solvent
was then evaporated. Two successive column chromatography
(SiO2; CH2Cl2/hexane, 1:1 then 7:3) yielded 8 (343 mg, 17%) and
9 (770 mg, 53%).
9: Yellow glassy product. IR (neat): ν = 1704 (C=O) cm–1. 1H
˜
NMR (300 MHz, CDCl3): δ = 0.88 (m, 36 H, CH3), 1.10–1.50 (m,
216 H, CH2), 1.75 (m, 24 H, CH2), 3.94 (m, 24 H, OCH2), 6.60 (s,
8 H, Ar-H), 6.72 (d, J = 17 Hz, 2 H, =CH), 6.78 (AB, J = 17 Hz,
4 H, CH=CH), 6.80 (m, 8 H, Ar-H), 6.2 (d, J = 17 Hz, 2 H, =CH),
7.05 (m, 12 H, Ar-H), 7.41 (d, J = 8 Hz, 4 H, Ar-H), 9.78 (s, 2 H,
CHO) ppm. 13C NMR (300 MHz, CDCl3): δ = 14.1, 22.7, 26.1,
29.3, 29.4, 29.6, 29.7, 30.3, 32.0, 69.1, 73.5, 105.1, 125.1, 127.3,
127.5, 128.3, 128.4, 128.6, 131.5, 131.9, 132.4, 132.5, 133.7, 134.5,
134.7, 138.3, 138.7, 139.0, 139.1, 140.1, 141.0, 147.0, 153.2,
Compound 14: A mixture of Co2(CO)8 (170 mg, 0.5 mmol), 6
(390 mg, 1.65 mmol), and 13 (960 mg, 3.30 mmol) in dry dioxane
(100 mL) was stirred at room temperature for 12 h, and the solvent
was then evaporated. Two successive column chromatography
(SiO2; CH2Cl2/hexane, 1:1) yielded 14 (660 mg, 49%). Yellow glassy
191.9 ppm. MS (MALDI-TOF): m/z
= 3210 [M +
H]+.
C220H342O14 (3211.13): calcd. C 82.29, H 10.74; found C 82.45, H
11.01.
product. IR (neat): ν = 1705 (C=O) cm–1. 1H NMR (300 MHz,
˜
Compound 10: A 1  LiAlH4 solution in THF (0.6 mL, 0.6 mmol)
was added to a stirred solution of 9 (740 mg, 0.23 mmol) in dry
THF (20 mL) at 0 °C. The resulting mixture was stirred for 4 h at
0 °C, then MeOH was carefully added. The resulting mixture was
filtered (Celite), and the solvent was evaporated. Column
chromatography (SiO2, CH2Cl2) gave 10 (560 mg, 76%) as a yellow
glassy product. UV/Vis (CH2Cl2): λ (ε, Lmol–1 cm–1) = 233
(106800), 338 (150200) nm. 1H NMR (300 MHz, CDCl3): δ = 0.85
(m, 36 H, CH3), 1.1–1.5 (m, 216 H, CH2), 1.75 (m, 24 H, CH2),
3.94 (m, 24 H, OCH2), 4.46 (s, 4 H, ArCH2), 6.59 (m, 4 H, Ar-H),
6.60 (s, 4 H, Ar-H), 6.72 (d, J = 17 Hz, 2 H, =CH), 6.80 (m, 20 H,
CH=CH and Ar-H), 6.84 (d, J = 17 Hz, 2 H, =CH), 7.04 (m, 8 H,
Ar-H) ppm. 13C NMR (300 MHz, CDCl3): δ = 14.1, 22.7, 26.1,
29.3, 29.4, 29.6, 29.7, 30.3, 31.9, 65.1, 69.1, 73.5, 105.0, 124.9,
125.4, 127.8, 128.0, 131.7, 132.6, 134.2, 138.2, 139.8, 140.2,
CDCl3): δ = 1.09 (s, 36 H, tBu), 6.73 (AAЈXXЈ, JAX = 7 Hz, 8 H,
Ar-H), 6.74 (AAЈXXЈ, JAX = 7 Hz, 8 H, Ar-H), 7.19 (AAЈXXЈ,
JAX = 7 Hz, 8 H, Ar-H), 9.76 (s, 2 H, CHO) ppm. MS (MALDI-
TOF): m/z = 815 [M +H]+. C60H62O2 (815.15): calcd. C 88.41, H
7.67; found C 88.29, H 7.73.
Compound 15: A 1  LiAlH4 solution in THF (2.4 mL, 2.4 mmol)
was added to a stirred solution of 14 (660 mg, 0.81 mmol) in dry
THF (25 mL) at 0 °C. The resulting mixture was stirred for 3 h at
0 °C, then MeOH was carefully added. The resulting mixture was
filtered (Celite). The solvent was then evaporated to give 15
(450 mg, 68%) as a pale yellow solid. 1H NMR (300 MHz, CDCl3):
δ = 1.07 (s, 18 H, tBu), 1.09 (s, 18 H, tBu), 4.43 (s, 4 H, Ar-CH2),
6.66 (m, 8 H, Ar-H), 6.80 (m, 16 H, Ar-H) ppm. C60H66O2
(819.18): calcd. C 87.97, H 8.12; found C 87.75, H 8.43.
Compound 16: DCC (270 mg, 1.32 mmol) was added to a stirred
solution of 15 (450 mg, 0.55 mmol), 11 (680 mg, 1.21 mmol), and
DMAP (27 mg, 0.22 mmol) in CH2Cl2 (30 mL) at 0 °C. After 1 h,
the mixture was allowed to slowly warm to room temperature
(within 1 h), then stirred for 24 h, and filtered, and the solvent was
then evaporated. Column chromatography (SiO2; hexane/CH2Cl2,
153.2 ppm. MS (MALDI-TOF): m/z
C220H346O14 (3215.16): calcd. C 82.19, H 10.85; found C 82.25, H
11.11.
= 3214 [M +
H]+.
Compound 12: DCC (72 mg, 0.35 mmol) was added to a stirred
solution of 10 (470 mg, 0.15 mmol), 11 (271 mg, 0.48 mmol), and
DMAP (7 mg, 0.06 mmol) in CH2Cl2 (30 mL) at 0 °C. After 1 h,
the mixture was allowed to slowly warm to room temperature
(within 1 h), then stirred for 28 h, and filtered, and the solvent was
then evaporated. Column chromatography (SiO2; hexane/CH2Cl2,
1:1) yielded 12 (470 mg, 75%) as a yellow glassy product. 1H NMR
(300 MHz, CDCl3): δ = 0.88 (m, 48 H, CH3), 1.10–1.60 (m, 288 H,
CH2), 1.74 (m, 32 H, CH2), 3.39 [s, 4 H, CH2(CO2R)2], 3.92 (m,
32 H, OCH2), 4.96 (s, 4 H, Ar-CH2), 5.00 (s, 4 H, Ar-CH2), 6.38
(s, 2 H, Ar-H), 6.42 (s, 4 H, Ar-H), 6.59 (s, 8 H, Ar-H), 6.78 (m,
24 H, CH=CH and Ar-H), 7.00 (2d, J = 8 Hz, 8 H, Ar-H) ppm.
1:1) yielded 16 (550 mg, 53%) as a yellow glassy product. IR (neat):
1
ν = 1739 (C=O) cm–1. H NMR (300 MHz, CDCl ): δ = 0.86 (t, J
˜
3
= 7 Hz, 12 H, CH3), 1.10 (s, 36 H, tBu), 1.27 (m, 72 H, CH2), 1.76
(m, 8 H, CH2), 3.39 [s, 4 H, CH2(CO2R)2], 3.91 (m, 8 H, OCH2),
4.95 (s, 4 H, Ar-CH2), 5.06 (s, 4 H, Ar-CH2), 6.43 (m, 2 H, Ar-H),
6.64 (m, 4 H, Ar-H), 6.80 (m, 24 H, Ar-H) ppm. 13C NMR
(75 MHz, CDCl3): δ = 14.1, 22.6, 26.0, 26.9, 29.2, 29.3, 29.4, 29.55,
29.6, 29.65, 31.1, 31.9, 33.9, 34.0, 41.3, 67.0, 67.1, 68.0, 101.1,
106.4, 123.0, 123.2, 126.3, 130.9, 131.0, 131.7, 131.75, 137.2, 137.5,
137.7, 139.2, 140.3, 140.9, 141.0, 147.4, 147.6, 160.4, 166.0,
166.2 ppm. C128H178O12 (1908.81): calcd. C 80.54, H 9.40; found
C 80.25, H 9.40.
Compound 1: DBU (0.08 mL, 0.55 mmol) was added to a stirred
solution of C60 (79 mg, 0.109 mmol), I2 (61 mg, 0.24 mmol), and
12 (470 mg, 0.109 mmol) in toluene (200 mL) at room temperature.
The solution was stirred for 3 h, filtered through a short plug of
Compound 17: DBU (0.16 mL, 1.04 mmol) was added to a stirred
solution of C60 (187 mg, 0.260 mmol), I2 (145 mg, 0.57 mmol), and
Eur. J. Org. Chem. 2009, 3879–3884
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3883

T. M. Figueira-Duarte, A. Gégout, J. Olivier, F. Cardinali, J.-F. Nierengarten
FULL PAPER
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16 (500 mg, 0.26 mmol) in toluene (500 mL) at room temperature.
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plug of SiO2 (toluene then CH2Cl2). The solvent was then evapo-
rated. Column chromatography (SiO2; hexane/CH2Cl2, 3:2) fol-
lowed by gel permeation chromatography (Biorad, Biobeads SX-1,
CH2Cl2) yielded 17 (170 mg, 25%) as a dark brown glassy product.
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IR (CH Cl ): ν = 1745 (C=O) cm–1. UV/Vis (CH Cl ): λ (ε,
˜
2
2
2
2
Lmol–1 cm–1) = 252 (220000), 320 (140000), 395 (sh., 8000), 408
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2 Hz, 1 H, Ar-H), 6.84–6.54 (m, 28 H, Ar-H) ppm. 13C NMR
(75 MHz, CDCl3): δ = 14.1, 22.7, 26.0, 26.1, 29.2, 29.25, 29.3, 29.4,
29.45, 29.6, 29.7, 31.1, 31.2, 31.9, 33.9, 34.0, 34.1, 51.4, 53.7, 67.0,
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141.3, 141.4, 141.6, 141.8, 142.0, 142.1, 142.2, 142.5, 142.7, 142.8,
142.9, 143.2, 143.4, 143.5, 143.6, 143.65, 143.7, 143.8, 143.9, 144.0,
144.2, 144.3, 144.5, 144.6, 144.65, 144.7, 144.8, 144.9, 144.95,
145.0, 145.05, 145.1, 145.4, 145.6, 145.9, 146.0, 146.2, 146.3,
146.35, 146.9, 147.1, 147.2, 147.4, 147.45, 147.6, 147.7, 148.5,
160.4, 162.9, 163.1, 163.3, 163.4 ppm. MALDI-MS: m/z = 2626 [M
+ H]+. C188H174O12 (2625.44): calcd. C 86.01, H 6.68; found C
85.69, H 6.69.
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Acknowledgments
This research was supported by the Centre National de la Recher-
che Scientifique (UMR 7509) and the Agence Nationale de la Re-
cherche (Solaire Photovoltaïque – Nanorgysol). A. G. thanks the
Agence de l’Environnement et de la Maîtrise de l’Energie – Région
Alsace for her fellowship.
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Received: March 18, 2009
Published Online: May 14, 2009
3884
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© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2009, 3879–3884