Regioselective Preparation of Fullerene Bis-adducts from Cleavable Macrocyclic Bis-malonates

Article abstract of DOI:10.1002/ejoc.202100571

A series of macrocyclic bis-malonates incorporating either di-tert-butylsilylene or tetra-iso-propyldisiloxane subunits have been prepared and used for the regioselective bis-functionalization of [60]fullerene by double Bingel cyclopropanations. By system

Full text of DOI:10.1002/ejoc.202100571

European Journal of Organic Chemistry
Accepted Article
Accepted Article
Title: Regioselective Preparation of Fullerene Bis-adducts From
Cleavable Macrocyclic Bis-malonates
Authors: Thi Minh Nguyet Trinh, Franck Schillinger, Sebastiano
Guerra, Eric Meichsner, Iwona Nierengarten, Uwe Hahn,
Michel Holler, and Jean-Francois Nierengarten
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of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
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to this Accepted Article as a result of editing. Readers should obtain
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To be cited as: Eur. J. Org. Chem. 10.1002/ejoc.202100571
Link to VoR: https://doi.org/10.1002/ejoc.202100571
01/2020

10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
Regioselective Preparation of Fullerene Bis-adducts From
Cleavable Macrocyclic Bis-malonates
Thi Minh Nguyet Trinh,[a] Franck Schillinger,[a] Sebastiano Guerra,[a] Eric Meichsner,[a] Iwona
Nierengarten,[a] Uwe Hahn,[a] Michel Holler,[a] and Jean-François Nierengarten*[a]
Dedicated to Prof. Remi Chauvin on the occasion of his 60th birthday
[a]
Dr T. M. N. Trinh, Dr. F. Schillinger, Dr. S. Guerra, Dr. E. Meichsner, Dr. I. Nierengarten, Dr. U. Hahn, Dr. M. Holler, Dr. J.-F. Nierengarten
Laboratoire de Chimie des Matériaux Moléculaires
Université de Strasbourg et CNRS (UMR 7042 LIMA), Ecole Européenne de Chimie, Polymères et Matériaux
25 rue Becquerel, 67087 Strasbourg Cedex 2, France
E-mail : nierengarten@unistra.fr – Homepage URL: http://nierengartengroup.com
Supporting information for this article is given via a link at the end of the document.
Abstract: A series of macrocyclic bis-malonates incorporating either
di-tert-butylsilylene or tetra-iso-propyldisiloxane subunits have been
prepared and used for the regioselective bis-functionalization of
[60]fullerene by double Bingel cyclopropanations. By systematically
changing the length and the rigidity of the spacer units linking the
malonate moieties to the silylated protecting groups, fullerene bis-
adducts with different addition patterns have been obtained. Finally,
the bridging di-tert-butylsilylene groups have been cleaved to afford
the corresponding acyclic fullerene bis-adducts bearing four alcohol
functions.
in reactivity of the different double bonds is nicely correlated with
their LUMO coefficients in C60(CO2Et)2. Despite a preferential
functionalization of specific double bonds, the preparative
synthesis of fullerene bis-adducts by successive reactions at the
C60 core remains limited as complex mixtures are produced and
tedious chromatographic separations are necessary for their
purification. The development of selective routes to produce
isomerically pure fullerene multi-adducts became rapidly a central
topic in fullerene chemistry. The first powerful strategy for the
regioselective preparation of fullerene multiple adducts has been
introduced by Diederich in 1994 and is based on tether-directed
remote functionalization.[6,7] The same group has also reported a
direct bis-functionalization of C60 based on the macrocyclization
of bis-malonate derivatives onto the fullerene core (Figure 1C).[8]
The linker between the two malonate moieties acts as a directing
tether thus allowing a highly regioselective double Bingel addition
to one carbon sphere.[9,10] This methodology has been further
extended by Hirsch and co-workers to macrocyclic malonates.[11-
Introduction
The cyclopropanation of [60]fullerene with stabilized a-
halocarbanions, the so-called Bingel reaction, is one of the most
efficient tools for the preparation of methanofullerenes.[1-3] This
reaction proceeds by addition of a stabilized a-halocarbanion to
one of the 6-6 double bonds of C60 (bonds at the junction between
two six-membered rings), followed by an intramolecular
displacement of the halide by the anionic center generated on the
C60 core. As all the thirty 6-6 double bonds of plain C60 are
equivalent, only one mono-addition product is possible. In
contrast, monofunctionalized fullerene derivatives possess nine
different 6-6 double bonds (Figure 1).[4] Addition of a second
addend to a C2v-symmetrical C60 mono-adduct can in principle
lead to nine different regioisomeric bis-adducts. Relative to the
first addend, the second one can be located either in the same
hemisphere (cis), in the opposite one (trans), or on the equatorial
belt (e).[4] The sequential double Bingel cyclopropanation of C60
with diethyl bromomalonate has been investigated in details by
Hirsch and co-workers (Figure 1B).[5] In this particular case, the
two addends are identical and the symmetry of the C60 bis-
adducts can be either C2 (cis-3, trans-2, trans-3), Cs (cis-1, cis-2,
e, trans-4), or D2h (trans-1). Moreover, a second addition onto the
e-edge or e-face position leads to identical products (simply noted
e in this particular case). Out of the eight possible bis-adducts,
only the cis-1 has not been obtained for steric reasons. The
product distribution is however not statistical and the preferred
reaction products are the e and trans-3 isomers.[5] The difference
13]
In this case, the regioselectivity is not only governed by the
length of the spacer but also by the even distribution of the strain
within the macrocyclic malonates. As a result, formation of C2-
symmetrical bis-adducts is favored when starting from
macrocyclic malonates containing alkane chain spacers of
identical length.[11] As part of this research, we have incorporated
di-tert-butylsilylene protecting groups in the bridging units of linear
and macrocyclic bis-malonates (Figure 1D).[14,15] Upon
regioselective bis-functionalization of C60, our preliminary results
have also shown that a desilylation reaction is possible to afford
the corresponding acyclic polyols.[14] In this full paper, we now
report
incorporating
a
complete series of macrocyclic bis-malonates
either di-tert-butylsilylene or tetra-iso-
propyldisiloxane subunits in order to fully explore their potential
for the regioselective bis-functionalization of C60. By
systematically changing the length and the rigidity of the spacer
units linking the malonate moieties to the silylated protecting
groups, fullerene bis-adducts with different addition patterns
became accessible. Interestingly, introduction of the silylene and
disiloxane groups brings additional flexibility and influence the
overall strain of the system. In contrast to the observation of
Hirsch with macrocyclic malonates containing alkane chain
1
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10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
spacers, the bis-addition patterns with rotational symmetry are not Results and Discussion
favored anymore by reaction of C60 with symmetrical macrocyclic
bis-malonates incorporating di-tert-butylsilylene or tetra-iso-
propyldisiloxane subunits. Finally, the di-tert-butylsilylene
protecting groups have been cleaved to afford the corresponding
acyclic fullerene bis-adducts bearing four alcohol functions.
Preparation of macrocyclic bis-malonates.
A first series of macrocyclic bis-malonates incorporating rigid
aromatic spacer units between the malonate moieties to the
silylated protecting groups were prepared as shown in Scheme 1.
Reaction of methyl 4-(hydroxymethyl)benzoate (1) with di-tert-
butylsilylene bis(trifluoromethanesulfonate) (tBu2Si(OTf)2) in DMF
in the presence of pyridine (pyr) afforded 2 in 92% yield. The
reduction of the ester functions of 2 was first attempted with LiAlH4.
Under these conditions, the desired diol was not obtained due to
the concomitant cleavage of the silyl ethers. In contrast, when
diisobutylaluminum hydride (DIBAL-H) was used as the reducing
agent, compound 3 was obtained in good yields (92%). Reaction
of diol 3 with malonyl chloride was then performed in the presence
of 4-dimethylaminopyridine (DMAP) under peudo-high dilution
conditions. A mixture of cyclooligomers and polymers was thus
obtained. Macrocycles 4a and 4b were isolated by repeated
(A)
cis-1
cis-2
cis-3
e-edge e-face
cis
e
trans-4
trans-3
trans
trans-2
trans-1
(B)
chromatographic
separations.
The
20-membered
ring
O
O
O
O
macrocyclic mono-malonate 4a was thus isolated in 49% yield.
The corresponding 40-membered ring macrocyclic bis-malonate
was obtained in 9% yield. Compounds 7a and 7b were prepared
from alcohol 1 by following a similar synthetic route. Reaction of
1 with 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane (TIPDSiCl2)
followed by DIBAL-H reduction of the resulting 5 provided diol 6.
Treatment of 6 with malonyl chloride was then carried out under
pseudo-high dilution conditions to afford the 22- and 44-
membered ring macrocycles 7a and 7b in 73% and 5% yields,
respectively. In order to further increase the ring size of the
EtO
OEt
EtO
OEt
OEt
O
O
O
EtO
OEt
Br
O
EtO
NaH / PhMe
(C)
C60
O
O
O
O
O
O
I2 / DBU
PhMe
O
O
macrocyclic
bis-malonate
incorporating
rigid
spacers,
O
O
O
macrocycles 11a and 11b were prepared starting from biphenyl
derivative 8. Treatment of 8 with tBu2Si(OTf)2 provided 9 in 86%
yield. Reduction of 9 with DIBAL-H in CH2Cl2 at -15°C gave diol
10 in 67% yield. Finally, the 28- and 56-membered ring
macrocycles 11a and 11b were obtained in low yields by reaction
of 10 with malonyl chloride. The 1H and 13C NMR spectra of
macrocycles 4a-b, 7a-b and 11a-b were in full agreement with
their cyclooligomeric structures. It was however not possible to
fully confirm the proposed structures by mass spectrometry due
to high levels of fragmentation resulting from the cleavage of the
benzylic ester moieties during the MS analysis. Nonetheless,
based on the elution order of the compounds and on their relative
yields, compounds 4a, 7a and 11a are likely the cyclomonomeric
derivative, and 4b, 7b and 11b the corresponding cyclodimers.
This was fully confirmed upon functionalization of C60 with 4b, 7b
and 11b (vide infra).
O
OR
RO
RO
OR
(D)
O
O
O
O
O
O
O
C60
O
O
O
O
O
O
O
O
CBr4 / DBU
PhMe
O
(E)
Si
=
O
O
O
O
O
O
Macrocyclic bis-malonates 18a-e were prepared starting from
alkanediols 12a-e (Scheme 2). Initial attempts to produce 18a-e
by reaction of the corresponding di-tert-butyl silylene-bridged
diols and malonyl chloride provided mainly [1+1] cyclization
products and the desired [2+2] products were obtained in very low
yields. A stepwise synthetic route was therefore developed in
order to obtain the targeted bis-malonates more efficiently.
Specifically, a first malonate subunit was first decorated with two
appropriate groups bearing terminal alcohol groups. The resulting
diol was then engaged in the macrocyclization step with malonyl
chloride to generate the desired bis-malonates as the [1+1]
cyclization products.
Figure 1. (A) Positional relationships of the different 6,6 double bonds relative
to first addend in
fullerene monoadduct.[4] (B) Double Bingel
a
a
cyclopropanation investigated in details by Hirsch and co-workers.[5] (C)
Regioselective preparation of C60 bis-adducts based on the reaction of linear
bis-malonates with C60 reported by Diederich and co-workers.[8] (D)
Regioselective preparation of C60 bis-adducts based on the reaction of
macrocyclic bis-malonates with C60 reported by Hirsch and co-workers.[11] (E)
Our group has developed linear and macrocyclic bis-malonates incorporating
bridging di-tert-butylsilylene protecting groups that can be readily cleaved to
afford the corresponding acyclic fullerene polyols upon the regioselective bis-
functionalization of C60
[14]
.
2
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10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
O
O
O
O
Si
O
O
Si
O
O
O
O
(iv)
O
O
Si
+
Si
R
(i)
R
O
O
O
O
O
O
O
O
2 R = CO2Me
3 R = CH2OH
O
O
O
4b
OH
(iii)
4a
O
O
OMe
Si
Si
O
O
O
O
O
1
(ii)
Si
Si
O
O
O
Si
Si
(iv)
+
O
O
Si
Si
O
O
O
O
R
R
O
O
O
O
O
O
5 R = CO2Me
6 R = CH2OH
O
O
O
(iii)
7a
7b
O
Si
OH
O
O
Si
O
O
(i)
(iv)
O
O
O
O
+
Si
Si
R
O
OMe
R
O
O
O
O
9 R = CO2Me
8
(iii)
O
11a
O
O
11b
O
10 R = CH2OH
Scheme 1. Preparation of macrocyclic bis-malonates 4b, 7b and 11b. Reagents and conditions: (i) tBu2Si(OTf)2, DMF, pyr, rt (2: 92%; 9: 86%); (ii) TIPDSiCl2, DMF,
pyr, rt (99%); (iii) DIBAL-H, CH2Cl2, -15°C (3: 92%; 6: 77%; 10: 67%); (iv) malonyl chloride, CH2Cl2, DMAP, rt (4a: 49% and 4b: 9%; 7a: 73% and 7b: 5%; 11a: 12%
and 11b: 8%).
The selective mono-protection of diols 12a-e was carried out by
treatment with Ag2O and p-methoxybenzyl chloride (PMBCl)
according to the conditions reported by Bouzide and Sauvé.[16]
Reaction of the resulting mono-protected derivatives 13a-e with
tBu2Si(OTf)2 in the presence of pyr in DMF provided 14a-e.
formed and by-products were polymers. Their purification by
column chromatography was therefore easily achieved.
Considering their ring size ranging from 32 to 48 atoms,
macrocycles 18a-e were thus produced in good yields. Their
structure was fully confirmed by NMR spectroscopy and mass
spectrometry.
Treatment of 14a-e with
1
equiv. of 2,3-dichloro-5,6-
dicyanobenzoquinone (DDQ)[17] in CH2Cl2 containing a small
amount of water gave the corresponding mono-protected diols
15a-e. Subsequent reaction with malonyl chloride in the presence
of DMAP afforded malonates 16a-e. The choice of the appropriate
protecting groups for the two terminal alcohol functions of 16a-e
was essential to achieve their deprotection without affecting the
acid-sensitive bridging di-tert-butyl silylene groups and the base-
sensitive ester functions. The PMB protecting group was perfectly
suited for our purpose as its oxidative cleavage by treatment with
DDQ was performed under neutral conditions.[17] Both the ester
functions and the di-tert-butyl silylene groups remained intact
under these conditions and diols 17a-e were thus obtained in
good yields. Macrocyclic bis-malonates 18a-e were then prepared
by reaction of diols 17a-e with malonyl chloride in the presence of
DMAP. In all the cases, only the [1+1] cyclization product was
Bis-functionalization of C60 with macrocyclic bis-malonates.
Reactions of macrocyclic bis-malonates 4b, 7b and 11b with C60
were carried out under the typical conditions developed by
Diederich for the preparation of bis-adducts (Scheme 3).[8]
Specifically, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was
added to a solution of C60, iodine and the appropriate macrocyclic
bis-malonate (4b, 7b or 11b) in PhMe at room temperature. Under
these conditions, the a-iodo malonate intermediates needed for
the cyclopropanation of C60 are generated in situ by reaction of
the malonates with iodine. To favor the macrocyclizations onto the
C sphere and prevent intermolecular Bingel cyclopropanations
between monofunctionalized intermediates, all the reactions were
performed at low concentrations (ca. 0.3 mM for C60).
3
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10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
OPMB
OR
between the two reactive malonate moieties in 4a and 7a over a
shorter range. In this way, despite the conformational freedom
resulting from the presence of the silylated linkers, the reaction of
4a and 7a with C60 remains regioselective.
O
O
(ii)
n
HO
OR
n
Si
n
12a-e R = H
(i)
13a-e R = PMB
14a-e R = PMB
15a-e R = H
(iii)
Si
(iv)
O
O
O
O
O
O
n
n
O
O
O
O
O
O
Si
O
Si
O
O
(i)
O
19 trans-3 (C2)
4b
O
O
(54%)
OR
RO
n
n
16a-e R = PMB
(v)
12-18a n = 1
12-18b n = 2
12-18c n = 3
12-18d n = 4
12-18e n = 5
O
O
17a-e R = H
Si
O
(vi)
Si
Si
O
O
O
O
O
O
n
O
O
n
O
O
O
O
Si
Si
O
O
O
O
O
20 e (C1)
(15%)
O
O
O
(i)
n
n
7b
O
O
21 trans-3 (C2)
(26%)
18a-e
Scheme 2 Preparation of macrocyclic bis-malonates 18a-e. Reagents and
conditions: (i) PMBCl, Ag2O, CH2Cl2, rt (13a: 95%; 13b: 91%; 13c: 92%; 13d:
90%; 13e: 69%); (ii) tBu2Si(OTf)2, DMF, pyr, rt (14a: 60%; 14b: 91%; 14c: 59%;
14d: 79%; 14e: 83%); (iii) DDQ (1 equiv.), CH2Cl2, H2O, rt (15a: 47%; 15b: 47%;
15c: 60%; 15d: 51%; 15e: 50%); (iv) malonyl chloride (0.5 equiv.), CH2Cl2,
DMAP, rt (16a: 67%; 16b: 94%; 16c: 93%; 16d: 96%; 16e: 90%); (v) DDQ (2.5
equiv.), CH2Cl2, H2O, rt (15a: 47%; 15b: 47%; 15c: 60%; 15d: 51%; 15e: 50%);
(vi) malonyl chloride, CH2Cl2, DMAP, rt (16a: 67%; 16b: 94%; 16c: 93%; 16d:
96%; 16e: 90%); (vi) malonyl chloride (1 equiv.), CH2Cl2, DMAP, rt (18a: 50%;
18b: 28%; 18c: 30%; 18d: 19%; 18e: 19%).
O
O
O
Si
Si
O
Si
O
Under these conditions, reaction of 4b with C60 was highly
regioselective and trans-3 bis-adduct 19 was the only cyclization
product. It was obtained in a good yield (54%). In the case of 7b,
the reaction with C60 afforded two regioisomeric bis-adducts.
Upon purification by column chromatography, e bis-adduct 20 and
trans-3 bis-adduct 21 were obtained pure in 15% and 26% yields,
respectively. Incorporation of the slightly longer and more flexible
disiloxane moieties in the starting macrocycle clearly influenced
the outcome of the reaction, the bis-functionalization remained
however regioselective. In contrast, very limited regioselectivity
was observed when the largest macrocyclic bis-malonate (11b)
was used as the starting material. Three regioisomers were
isolated in pure form by column chromatography. Compounds 22
(trans-3), 23 (e) and 24 (cis-2) were thus obtained in 15%, 4% and
6% yields, respectively. Traces of several other bis-adducts were
also observed but these products could not be isolated in pure
form and/or were obtained in too small quantities to achieve
complete characterization. Despite the long rigid biphenyl units in
11b, the presence of the silylene linkers is at the origin of a large
conformational flexibility preventing the regioselective bis-
functionalization of C60 from 11b. In the case of 4b and 7b, the
shorter xylylene rigid spacers restricts the intramolecular distance
22 trans-3 (C2)
O
O
O
O
O
O
(15%)
O
O
(i)
23 e (C1)
(4%)
11b
24 cis-2 (Cs)
(6%)
O
O
Si
Scheme 3. Preparation of fullerene bis-adducts 19-24. Reagents and
conditions: (i) C60, DBU, I2, PhMe, rt.
Bis-adducts 19-24 were characterized by H and 13C NMR, UV-
1
vis and IR spectroscopies. Their structure was also confirmed by
their MALDI-TOF mass spectra showing the expected pseudo-
molecular ion peak in all the cases. To determine the relative
position of the two cyclopropane rings on the fullerene core in 19-
24, detailed analysis of their 1H and 13C NMR spectra was
4
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10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
necessary to first deduce their molecular symmetry. As typical
examples, the 1H NMR spectra recorded for compounds 22-24 in
CDCl3 are depicted in Figure 2. The spectrum of 23 is by far more
complex when compared to those of 22 and 24. The different
diastereotopic benzylic CH2 units are non-equivalent in the case
of 23 as attested by the presence of eight AB quartets between
4.4 and 5.2 ppm. Compound 23 is therefore C1 symmetric. This
was also confirmed by the complex set of signals observed in the
aromatic region corresponding to eight different AA’XX’ systems
for the protons of the different p-disubstituted phenyl units. For a
fullerene derivative obtained from a macrocyclic bis-malonate, the
only possible bis-addition pattern with a C1 symmetry is e. Owing
to the presence of a macrocyclic link joining the two cyclopropane
rings in 23, the Cs symmetry of the equatorial bis-addition pattern
is reduced to C1.
the case for compound 22 thus suggesting either a cis-3, trans-3
or trans-2 addition pattern. In contrast, 32 resonances are
expected for a CS-symmetrical fullerene bis-adduct (30 sp2
C
atoms with four showing half-intensity and 2 sp3 C atoms). This is
observed for compound 24 thus suggesting either a cis-2 or trans-
4 addition pattern. The relative position of the two cyclopropane
rings on the C60 core suggested by the molecular symmetry is
conveniently confirmed by their absorption spectra. The UV/vis
spectra of fullerene bis-adducts and therefore their colors are
dependent on the addition pattern and highly characteristic for
each regioisomer.[5-8] As depicted in Figure 3, the UV/vis spectra
recorded for compounds 22-24 clearly show the diagnostic
features previously reported for trans-3 (22), e (23) and cis-2 (24)
bis-adducts[5-8] thus providing definitive structural assignment for
these compounds.
Figure 3. Absorption spectra (CH2Cl2) of fullerene bis-adducts 22-24. The
characteristic features of trans-3 (22), e (23) and cis-2 (24) bis-addition patterns
are clearly observed. Solutions of 22 (trans-3) are purplish-brown, of 23 (e) red
and of 24 (cis-2) orange.
Figure 2. 1H NMR spectra of fullerene bis-adducts 22-24 (CDCl3, 400 MHz).
For both 22 and 24, only four sets of signals are observed for the
benzylic CH2 groups thus revealing a two-fold symmetrical
structure in both cases. The pattern observed for the protons of
the p-disubstituted phenyl units is also consistent with this
observation. Compounds 22 and 24 are therefore either Cs or C2
symmetric. Definitive conclusions about their symmetry was
obtained by careful analysis of their 13C NMR spectra. In particular,
30 fullerene resonances are expected for a C2-symmetrical
fullerene derivative (28 sp2 C atoms and 2 sp3 C atoms). This is
The bis-functionalization of C60 with macrocyclic bis-malonates
18a-e was achieved under the same conditions (Scheme 4).
Reaction of the smallest macrocycle (18a) with C60 in the
presence of iodine and DBU afforded Cs-symmetrical 25a with a
cis-2 addition pattern. Treatment of the larger macrocyclic bis-
malonate 18b-e with C60 gave two regioisomeric bis-adducts,
namely trans-3 26b-e and e 27b-e. For the -(CH2)5- derivative, the
trans-3 isomer (26b) was the major product (44%) while the e
5
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10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
isomer (27b) was only obtained in 12% yield. The trans-3/e ratio
was progressively displaced in favor of the e isomer by increasing
the size of the macrocyclic bis-malonate when going from 18b to
18e. Interestingly, the regioselectivity for the bis-cyclopropanation
of C60 with 18a-e is in apparent contradiction with the observations
reported by Hirsch with macrocyclic bis-malonates containing
linear alkane chain spacers of identical length.[11] In this particular
case, the regioselectivity was mainly governed by the even
distribution of the strain within the macrocyclic malonates thus
favoring the formation of C2-symmetrical fullerene bis-adducts.[11]
Obviously, introduction of the silylene spacers generates different
constraints within the macrocyclic bis-malonates and thus favors
the formation of fullerene bis-adducts with different symmetries.
To fully understand the outcome of these reactions,
computational studies were also performed. The molecular
geometry of all the possible regioisomers resulting from the
cyclization of 18a-e onto the C60 sphere were optimized at the
AM1 semi-empirical level. The relative heat of formation obtained
for all the possible regioisomers are summarized in Table 1.
Interestingly, the C2-symmetrical cis-3 regioisomer was notably
high in energy whatever the chain length. The steric constraints
resulting from the presence of the silylene linkers clearly prevents
the formation of this particular isomer. In the case of 18a, the cis-
2 regioisomer was found lower in energy when compared to all
the other regioisomers thus explaining well the exclusive
formation of 25a from 18a.
Table 1. Relative heat of formation in kJ/mol calculated for all the possible
[a]
regioisomeric fullerene bis-adducts obtained from the reaction 18a-e with C60
.
18a
18b
18c
18d
18e
-(CH2)4-
-(CH2)5-
-(CH2)6-
-(CH2)7-
-(CH2)8-
cis-2
(Cs)
0
0
0
+3
+20.6
+85.7
+12.1
+23.1
+6.5
+31.6
0
cis-3
(C2)
+97.2
+30.8
+57.2
+30.3
+219.2
+121.0
+18.1
+28.4
+15.3
+77.1
+71.3
+91.5
+7.3
+79.8
+1.1
+14.5
0
e
(C1)
trans-4
(Cs)
+16.2
+21.3
+53.2
+5.8
trans-3
(C2)
trans-2
(C2)
+28.0
+39.0
trans-1
(D2h
)
[a] The molecular geometry of the various regioisomers was optimized with
Spartan’18 Macintosh Parallel Edition (Wavefunction Inc., USA) at the AM1
semi-empirical level.
Si
Si
Si
O
O
O
O
O
O
O
O
(CH2)n
O
(CH2)n
(CH2)n
O
(CH2)n
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
(i)
(i)
O
O
+
18a-e
O
O
O
Si
(CH2)n
(CH2)n
(CH2)n
(CH2)n
O
O
O
O
26-27b, 29-30b: n = 5
26-27c, 29-30c: n = 6
26-27d, 29-30d: n = 7
26-27e, 29-30e: n = 8
Si
Si
25a cis-2 (Cs)
26b-e trans-3 (C2)
27b-e e (C1)
(ii)
(ii)
(ii)
HO (CH2)4
(CH2)4
OH
O
O
HO (CH2)n
HO (CH2)4
HO (CH2)n
(CH2)n
(CH2)4 OH
OH
O
(CH2)n
O
O
O
O
O
OH
O
O
O
O
O
O
O
O
O
O
O
(CH2)n OH
O
O
O
(CH2)n OH HO (CH2)n
O
HO (CH2)n
O
28a cis-2 (Cs)
29b-e trans-3 (C2)
30b-e e (Cs)
Scheme 4. Preparation of fullerene bis-adducts 25a, 26b-e and 27b-e followed by their deprotection to afford tetraols 28a, 29b-e and 30b-e. Reagents and
conditions: (i) C60, DBU, I2, PhMe, rt (25a: 39%; 26b: 44% and 27b: 12%; 26c: 33% and 27c: 27%; 26d: 20% and 27d: 30%; 26e: 16% and 27e: 21%); (ii) BF3∙Et2O,
CH2Cl2/CH3CN 2:1, rt (28a: 88%; 29b: 81%; 29c: 89%; 29d: 66%; 29e: 56%; 30b: 85%; 30c 80%; 30d: 70%; 30e: 82%).
6
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10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
In contrast, regioisomers 26b-e and 27b-e obtained
experimentally from 18b-e were not systematically the lowest in
energy. Indeed, distribution of the ring strain within the
macrocyclic bis-malonates plays an important role but the
cyclization reactions on the C60 core are also governed by the
relative reactivity of the different 6-6 double bonds upon the first
cyclopropanation. As soon as the ring strain is limited for the e
and trans-3 products, these addition patterns are favored as they
correspond also to the most reactive double bonds. The
regioselectivity results therefore from an interplay between steric
factors and kinetic effects. When compared to macrocyclic bis-
malonates containing linear alkane chain spacers, the silylene
linkers in 18a-e generate specific ring strains owing to their
stereochemical preferences and thus dramatically influence the
outcome of the cyclization reactions on the fullerene sphere.
and 30b-e as well as their absorption spectra were fully consistent
with the proposed addition patterns. Typical examples of 13C NMR
spectra are shown in Figures 4 and 5. For compound 28a, the 32
expected fullerene resonances of a Cs-symmetrical bis-adduct
are clearly observed. In particular, the presence of four half
intensity signals for four fullerene C atoms in the sp2 region is an
unambiguous signature of a Cs symmetrical structure. The two
fullerene sp3 C atoms (a and b) are observed at d = 70.5 and 67.7
ppm. The 13C NMR for bis-adduct 28a is thus fully consistent with
the proposed cis-2 addition pattern. This was further confirmed by
the UV/vis spectrum of 28a showing the diagnostic signatures of
a cis-2 bis-adduct. Compound 30b with its e addition pattern is
also Cs symmetric. There are also 28 pairs of equivalent C
fullerene atoms and four unique ones for 30b. However, out of the
three possible Cs-symmetrical addition patterns (cis-2, e and
trans-4), the only one for which three resonances are expected
for the sp3 fullerene C atoms is the e bis-adduct. This was further
confirmed by the presence of three resonances for the carbonyl
C atoms. Finally, the 13C NMR spectrum of compound 29b reveals
a C2-symmetrical structure. The spectrum of 29b is effectively
characterized by 28 resonances of similar intensity for the
fullerene sp2 C atoms and two signals for the sp3 fullerene C
atoms. In addition to its typical absorption spectrum for a trans-3
C60 bis-adduct, the stereochemistry of 29b was thus
unambiguously elucidated.
Desilylation of fullerene bis-adducts.
Cleavage of the connecting di-tert-butylsilylene protecting groups
in bis-adducts regioisomers 25a, 26b-e and 27b-e was achieved
in good yields by treatment with an excess of BF3∙Et2O in
CH2Cl2/CH3CN at room temperature (Scheme 4). The
corresponding tetraols 28a, 29b-e and 30b-e were thus obtained
in 56-89% yields. Removal of the di-tert-butylsilylene groups was
confirmed by disappearance of the typical tert-butyl signals in the
1H and 13C NMR spectra recorded for the final products. The
symmetry deduced from the NMR spectra of tetraols 28a, 29b-e
Figure 4. 13C NMR spectrum of fullerene bis-adduct 28a (CDCl3, 100 MHz). Four resonances corresponding to sp2 C atoms show half intensity (indicated by a black
dot), these signals correspond to the four unique fullerene sp2 C atoms located in the plane of symmetry. The 26 other resonances correspond each to a pair of
equivalent sp2 fullerene C atoms.
7
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10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
Figure 5. 13C NMR spectra of fullerene bis-adducts 29b and 30b (CDCl3, 100 MHz). In the case of 30b, the observation of three sp3 C fullerene atoms in a 2:1:1
ratio and a sp2 fullerene signal with half intensity (indicated by a black dot) is an unambiguous evidence for the Cs-symmetrical e addition pattern. The spectrum of
29b showing 28 resonances of similar intensity for the fullerene sp2 C atoms as well as two resonances for the sp3 fullerene C atoms is typical for a C2-symmetrical
fullerene bis-adduct.
8
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10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
Column chromatography (SiO2, CH2Cl2/MeOH, 98:2) yielded 3 (1.97 g,
92%) as a glassy product. IR (neat): 3321 (O-H) cm-1. 1H NMR (400 MHz,
CDCl3): δ = 7.32 (s, 8H), 4.93 (s, 4H), 4.68 (s, 4H), 1.10 (s, 18H) ppm. 13
NMR (100 MHz, CDCl3): δ = 140.7, 139.5, 127.0, 126.0, 65.4, 65.3, 28.0,
C
Conclusion
21.4 ppm.
Cleavable silylated-tethered macrocyclic bis-malonates have
been used for the regioselective preparation of fullerene bis-
adducts. By systematically changing the length and the rigidity of
the spacer units linking the two malonate moieties to the silyl units,
fullerene bis-adducts with different addition patterns have been
prepared. The regioselectivity results from the interplay between
structural factors and kinetic effects. The formation of bis-adducts
corresponding to the most reactive double bonds in the mono-
cyclopropanated fullerene intermediates are largely favored. For
this reason, mainly trans-3 and e bis-adducts have been obtained.
For the smallest macrocyclic precursor (18a), steric constraints
are too important in the e or trans-3 regioisomers and their
formation is not possible anymore. In this particular case, the cis-
2 fullerene bis-adduct is preferentially obtained. In contrast, when
the macrocyclic bis-adduct is too large and contains long rigid
units (11b), the bis-cyclopropanation of C60 is poorly
regioselective. Finally, desilylation of the macrocyclic fullerene
bis-adducts has been successfully achieved to generate the
corresponding acyclic fullerene bis-adducts bearing four terminal
alcohol functions. Easy access to these valuable building blocks
opens new perspective in the chemistry of multi-functionalized
fullerene derivatives for applications in biology or in materials
science.
Compounds 4a and 4b. A solution of malonyl chloride (0.5 mL, 5.2 mmol)
in CH2Cl2 (100 mL) was added dropwise to a solution of 3 (1.97 g, 4.73
mmol) and DMAP (1.27 g, 10.4 mmol) in CH2Cl2 (430 mL). The resulting
mixture was stirred at room temperature for 2 h, then filtered (SiO2, CH2Cl2)
and concentrated. Column chromatography (SiO2, CH2Cl2/cyclohexane,
9:1) yielded 4a (1.13 g, 49%) and 4b (0.21 g, 9%) as glassy products. 4a:
IR (neat): 1732 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.01 (s, 8H),
5.13 (s, 4H), 4.88 (s, 4H), 3.51 (s, 2H), 1.14 (s, 18H) ppm. 13C NMR (100
MHz, CDCl3): δ = 166.0, 141.0, 133.5, 127.3, 126.0, 66.8, 65.7, 42.4, 28.2,
21.3 ppm. 4b: 1H NMR (400 MHz, CDCl3): δ = 7.25 (s, 16H), 5.14 (s, 8H),
4.87 (s, 8H), 3.47 (s, 4H), 1.10 (s, 36H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 166.2, 141.4, 133.8, 128.2, 125.9, 67.1, 65.2, 41.7, 28.0, 21.4 ppm.
Compound 5. TIPDSiCl2 (2.47 mL, 7.9 mmol) was added to a solution of
1 (2.77 g, 16.7 mmol) and pyridine (1.5 mL, 18.5 mmol) in DMF (9 mL).
The mixture was stirred overnight at room temperature, then H2O was
added and the product was extracted with ether. The organic layer was
dried (MgSO4), filtered and concentrated. Column chromatography (SiO2,
CH2Cl2/cyclohexane, 8:2) yielded 5 (4.53 g, 99%) as a glassy product. IR
(neat): 1724 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.98 (d, J = 8 Hz,
4H), 7.34 (d, J = 8 Hz, 4H), 4.88 (s, 4H), 3.91 (s, 6H), 1.06 (m, 28H) ppm.
13C NMR (100 MHz, CDCl3): δ = 167.0, 146.3, 129.5, 128.8, 125.5, 63.8,
52.0, 17.4, 17.3, 13.0 ppm.
Compound 6. A solution of DIBAL-H in THF (1 M, 33 mL, 33 mmol) was
added dropwise to a stirred solution of 5 (4.51 g, 7.85 mmol) in dry THF
(35 mL) at -15°C. After 3 h, MeOH and NH4Cl (aq.) were added. The
resulting mixture was filtered (Celite) and concentrated. Column
chromatography (SiO2, CH2Cl2/cyclohexane, 8:2 to CH2Cl2/MeOH, 95:5)
yielded 6 (3.15 g, 77%) as a glassy product. IR (neat): 3325 (O-H) cm-1.
1H NMR (400 MHz, CDCl3): δ = 7.27 (s, 8H), 4.84 (s, 4H), 4.65 (s, 4H),
1.08 (m, 28H) ppm. 13C NMR (100 MHz, CDCl3): δ = 140.7, 139.4, 126.9,
126.1, 65.2, 64.0, 17.4, 17.4, 13.1 ppm.
Experimental Section
General methods
Reagents were purchased as reagent grade and used without further
purification unless specified. All reactions were performed in standard
glassware under an inert Ar atmosphere. Evaporation and concentration
were done at water aspirator pressure and drying in vacuo at 10-2 Torr.
Column chromatography: silica gel 60 (230-400 mesh, 0.040-0.063 mm)
was purchased from E. Merck. Thin Layer Chromatography (TLC) was
performed on aluminum sheets coated with silica gel 60 F254 purchased
from E. Merck. NMR spectra were recorded with a Bruker AC 300 or AC
400 spectrometer with solvent peaks as reference. IR spectra (cm-1) were
Compounds 7a and 7b. A solution of malonyl chloride (0.94 g, 6.67 mmol)
in CH2Cl2 (100 mL) was added dropwise to a solution of 6 (3.14 g, 6.05
mmol) and DMAP (1.77g, 14.5 mmol) in CH2Cl2 (590 mL). After 2 h, the
resulting mixture was filtered (SiO2, CH2Cl2) and concentrated. Column
chromatography (SiO2, CH2Cl2/cyclohexane, 9:1) gave 7a (2.59 g, 4.4
mmol, 73%) and 7b (177 mg, 0.14 mmol, 5%) as glassy products. 7a: IR
(neat): 1734 (C=O) cm-1. 1H NMR (300 MHz, CDCl3): δ = 7.13 (d, J = 8 Hz,
4H), 7.04 (d, J = 8 Hz, 4H), 5.12 (s, 4H), 4.85 (s, 4H), 3.49 (s, 2H), 1.11 (s,
28H) ppm. 13C NMR (75 MHz, CDCl3): δ = 166.0, 141.1, 133.4, 127.8,
125.9, 67.0, 63.9, 42.3, 17.4 (two peaks), 13.1 ppm. 7b: 1H NMR (400 MHz,
CDCl3): δ = 7.22 (m, 16H), 5.12 (s, 8H), 4.77 (s, 8H), 3.44 (s, 4H), 1.07 (s,
56H) ppm. 13C NMR (100 MHz, CDCl3): δ = 166.3, 141.7, 133.7, 128.2,
125.9, 67.1, 63.8, 41.5, 17.4, 13.0 ppm.
recorded with
a Perkin–Elmer Spectrum One spectrophotometer.
Absorption spectral measurements were carried out in QS Hellma cuvettes
with a PerkinElmer Lambda 365 spectrophotometer equipped with PCB
1500 water peltier system. MALDI-TOF mass spectra were recorded on a
Bruker ULTRAFLEX TOF/TOF mass spectrometer by the analytical
service of the School of Chemistry (Strasbourg, France).
Compound 2. tBu2Si(OTf)2 (5.0 g, 11.35 mmol) was added slowly to a
solution of 1 (3.96 g, 23.8 mmol) and pyridine (2.1 mL, 26.1 mmol) in dry
DMF (13 mL). The resulting mixture was stirred overnight at room
temperature, then water was added and the product was extracted with
Et2O. The organic layer was washed, dried (MgSO4) and concentrated.
Column chromatography (SiO2, CH2Cl2/cyclohexane 8:2) gave 2 (4.94 g,
92%) as a colorless glassy product. IR (neat): 1723 (C=O) cm-1. 1H NMR
(400 MHz, CDCl3): δ = 8.00 (d, J = 8 Hz, 4H), 7.36 (d, J = 8 Hz, 4H), 4.96
(s, 4H), 3.92 (s, 6H), 1.11 (s, 18H) ppm. 13C NMR (100 MHz, CDCl3): δ =
167.0, 146.2, 129.6, 128.9, 125.5, 65.2, 52.0, 27.9, 21.4 ppm.
Compound 9. tBu2Si(OTf)2 (2.0 mL, 6.1 mmol) was added to a solution of
8 (3.19 g, 13.2 mmol) and pyridine (1.1 mL, 13.5 mmol) in DMF (2 mL).
The resulting mixture was stirred overnight at rt, then water was added and
the product was extracted with CH2Cl2. The organic layer was washed with
H2O, dried (MgSO4) and concentrated. Column chromatography (SiO2,
CH2Cl2/cyclohexane 7:3) yielded 9 (3.31 g, 86%) as a glassy product. IR
(neat): 1721 (C=O) cm-1. 1H NMR (400 MHz, CDCl3) δ = 8.09 (d, J = 8 Hz,
4H), 7.66 (d, J = 8 Hz, 4H), 7.60 (d, J = 8 Hz, 4H), 7.43 (d, J = 8 Hz, 4H),
5.01 (s, 4H), 3.94 (s, 6H), 1.14 (s, 18H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 167.0, 145.4, 141.3, 138.6, 130.1, 128.8, 127.1, 126.9, 126.3, 65.3,
52.1, 28.0, 21.4 ppm.
Compound 3. A solution of DIBAL-H in CH2Cl2 (1 M, 22 mL, 22 mmol)
was added dropwise to a stirred solution of 2 (2.42 g, 5.12 mmol) in dry
CH2Cl2 (20 mL) at -15°C. After 3 h, MeOH and NH4Cl (aq.) were added
carefully. The resulting mixture was filtered (Celite) and concentrated.
Compound 10. A solution of DIBAL-H in THF (1M, 20.3 mL, 20.3 mmol)
was added dropwise to a stirred solution of 9 (3.03 g, 4.8 mmol) in CH2Cl2
9
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10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
(20 mL) at -15°C. After for 3h, MeOH and NH4Cl (aq) were added. The
resulting mixture was filtered (Celite) and concentrated. Column
chromatography (SiO2, CH2Cl2/MeOH, 96:4) yielded 10 (1.85 g, 67%) as
a glassy product. IR (neat): 3311 (br, O-H) cm-1. 1H NMR (400 MHz,
CDCl3): δ = 7.59 (d, J = 8 Hz, 4H), 7.56 (d, J = 8 Hz, 4H), 7.43 (d, J = 8 Hz,
4H), 7.41 (d, J = 8 Hz, 4H), 5.01 (s, 4H), 4.74 (s, 4H), 1.14 (s, 18H) ppm.
13C NMR (100 MHz, CDCl3): δ = 140.5, 140.4, 139.7, 139.4, 127.5, 127.2,
126.9, 126.3, 65.4, 65.1, 28.0, 21.4 ppm.
δ = 159.1, 130.8, 129.2, 113.7, 72.5, 70.2, 63.1, 55.3, 32.8, 29.8, 29.4,
29.3, 26.1, 25.7 ppm.
General procedure for the silylation of mono-protected diols (14a-e).
tBu2Si(OTf)2 (1 eq.) was added slowly to a solution of 13a-e (2 eq.) and
pyridine (or imidazole) (2 eq.) in DMF. The resulting mixture was stirred
overnight at room temperature, then water was added and the product was
extracted with Et2O. The organic layer was washed, dried (MgSO4) and
concentrated. Column chromatography (SiO2, CH2Cl2/cyclohexane to
CH2Cl2/MeOH) gave 14a-e.
Compounds 11a and 11b. A solution of malonyl chloride (0.32 mL, 3.29
mmol) in CH2Cl2 (100 mL) was added dropwise to a solution of 10 (1.85 g,
3.2 mmol) and DMAP (1.47 g, 12 mmol) in CH2Cl2 (300 mL). The resulting
mixture was stirred at room temperature for 2 h, then filtered (SiO2, CH2Cl2)
Compound 14a. Prepared from 13a (7.30 g, 34.7 mmol), tBu2Si(OTf)2 (5.1
ml, 15.6 mmol) and obtained as a colorless oil (5.3 g, 60%). 1H NMR (400
MHz, CDCl3): δ = 7.25 (d, J = 8 Hz, 4H), 6.87 (d, J = 8 Hz, 4H), 4.43 (s,
4H), 3.81(t, J = 6 Hz, 4H), 3.80 (s, 6H), 3.47 (t, J = 6 Hz, 4H), 1,69 (m, 4H),
1,61 (m, 4H), 0.98 (s, 18H) ppm. 13C NMR (100 MHz, CDCl3): δ = 159.0,
130.7, 129.2, 113.7, 72.5, 70.0, 63.6, 55.3, 29.6, 27.9, 26.2, 21.1 ppm.
and
concentrated.
Column
chromatography
(SiO2,
CH2Cl2/cyclohexane/ether, 7:2:1) yielded 11a (250 mg, 12%) and 11b (170
mg, 8%) as colorless glassy products. 11a: IR (neat): 1754 (C=O), 1725
(C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.29 (d, J = 8 Hz, 4H), 7.21
(d, J = 8Hz, 4H), 7.19 (d, J = 8 Hz, 4H), 7.07 (d, J = 8 Hz, 4H), 5.22 (s, 4H),
4.98 (s, 4H), 3.56 (s, 2H), 1.17 (s, 18H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 166.1, 140.7, 140.3, 138.5, 133.8, 128.2, 127.0, 126.4 (two peaks),
67.0, 66.0, 42.3, 28.3, 21.5 ppm. 11b: 1H NMR (400 MHz, CDCl3): δ =
7.54-7.46 (m, 16H), 7.40-7.32 (m, 16H), 5.21 (s, 8H), 4.99 (s, 8H), 3.53 (s,
4H), 1.16 (s, 36H) ppm. 13C NMR (100 MHz, CDCl3): δ = 166.2, 141.1,
140.4, 139.1, 134.0, 128.9, 128.8, 127.1, 126.9, 126.3, 67.0, 65.4, 41.9,
28.1, 21.5 ppm.
Compound 14b. Prepared from 13b (5.6 g, 25.0 mmol), tBu2Si(OTf)2 (3.7
ml, 11.3 mmol) and obtained as a colorless oil (6.1 g, 91%). 1H NMR (400
MHz, CDCl3): δ = 7.25 (d, J = 8 Hz, 4H), 6.87 (d, J = 8 Hz, 4H), 4.43 (s,
4H), 3.83 (m, 10H), 3.45 (t, J = 7 Hz, 4H), 1.59-1.45 (m, 12H), 0.99 (s,
18H) ppm. 13C NMR (100 MHz, CDCl3): δ = 159.1, 130.8, 129.1, 113.7,
72.5, 70.2, 63.7, 55.3, 32.7, 29.6, 27.9, 22.5, 21.2 ppm.
Compound 14c. Prepared from 13c (6.4 g, 26.9 mmol), tBu2Si(OTf)2 (4.0
ml, 12.3 mmol) and obtained as a colorless oil (4.5 g, 59%). 1H NMR (400
MHz, CDCl3): δ = 7.25 (d, J = 8 Hz, 4H), 6.87 (d, J = 8 Hz, 4H), 4.43 (s,
4H), 3.80 (s, 6H), 3.79 (t, J = 6 Hz, 4H), 3.44 (t, J = 6 Hz, 4H), 1.63-1.58
(m, 8H), 1.40 (m, 8H), 0.99 (s, 18H) ppm. 13C NMR (100 MHz, CDCl3): δ
= 159.1, 130.8, 129.2, 113.7, 72.6, 70.2, 63.7, 55.3, 32.9, 29.9, 27.9, 26.1,
25.7, 21.1 ppm.
General procedure for the mono-protection of diols (12a-e). A solution
of PMB-Cl (1eq.) in CH2Cl2 was added dropwise to a solution of the
appropriate diol (12a-e) (2-3 eq.) and Ag2O (1 eq.) in CH2Cl2. The resulting
mixture was stirred overnight at room temperature, then filtered through a
plug (SiO2, CH2Cl2/EtOAc, 9:1) and concentrated. Column
chromatography (SiO2, CH2Cl2/EtOAc) gave 13a-e.
Compound 13a. Prepared from 12a (10.0 g, 111 mmol), PMB-Cl (5.0 ml,
36.7 mmol) and obtained as a colorless oil (7.4 g, 95%). IR (neat): 3392
(br, OH) cm-1. 1H NMR (300 MHz, CDCl3): δ = 7.25 (d, J = 8 Hz, 2H), 6.87
(d, J = 8 Hz, 2H), 4.43 (s, 2H), 3.80 (s, 3H), 3.62 (t, J = 7 Hz, 2H), 3.45 (t,
J = 7 Hz, 2H), 1.79 (m, 4H) ppm. 13C NMR (100 MHz, CDCl3): δ = 159.2,
130.2, 129.3, 113.8, 72.7, 70.1, 62.7, 55.3, 30.2, 26.8 ppm.
Compound 14d. Prepared from 13d (6.30 g, 25 mmol), tBu2Si(OTf)2 (5.0
ml, 15.3 mmol) and obtained as a colorless oil (7.85 g, 79%). 1H NMR (400
MHz, CDCl3): δ = 7.27 (d, J = 8 Hz, 4H), 6.87 (d, J = 8 Hz, 4H), 4.43 (s,
4H), 3.80 (s, 6H), 3.79 (t, J = 6 Hz, 4H), 3.43 (t, J = 6 Hz, 4H), 1.56 (m,
8H), 1.34 (m, 12H), 0.99 (s, 18H) ppm. 13C NMR (100 MHz, CDCl3): δ =
159.0, 130.8, 129.2, 113.7, 72.5, 70.2, 63.8, 55.3, 32.9, 29.8, 29.3, 27.9,
26.3, 25.8, 21.2 ppm.
Compound 13b. Prepared from 12b (10.0 g, 96 mmol), PMB-Cl (4.4 ml,
32.3 mmol) and obtained as a colorless oil (6.6 g, 91%). IR (neat): 3392
(br, OH) cm-1. 1H NMR (300 MHz, CDCl3): δ = 7.25 (d, J = 8 Hz, 2H), 6.87
(d, J = 8 Hz, 2H), 4.43 (s, 2H), 3.80 (s, 3H), 3.62 (t, J = 7 Hz, 2H), 3.45 (t,
J = 7 Hz, 2H), 1.58 (m, 4H), 1.43 (m, 2H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 159.1, 130.7, 129.1, 113.7, 72.6, 70.0, 62.8, 55.3, 32.5, 29.5, 22.4 ppm.
Compound 14e. Prepared from 13e (5.8 g, 21.8 mmol), tBu2Si(OTf)2 (3.2
ml, 9.8 mmol) and obtained as a colorless oil (5.5 g, 83%). 1H NMR (400
MHz, CDCl3): δ = 7.25 (d, J = 8 Hz, 4H), 6.87 (d, J = 8 Hz, 4H), 4.43 (s,
4H), 3,80 (s, 6H), 3.79 (t, J = 6 Hz, 4H), 3.43 (t, J = 6 Hz, 4H), 1.55 (m,
8H), 1.32 (m, 16H), 0.99 (s, 18H) ppm. 13C NMR (100 MHz, CDCl3): δ =
159.0, 130.8, 129.2, 113.7, 72.5, 70.3, 63.8, 55.3, 32.9, 29.9, 29.5, 29.4,
27.9, 26.2, 25.8, 21.2 ppm.
Compound 13c. Prepared from 12c (10.0 g, 85 mmol), PMB-Cl (3.8 ml,
27.9 mmol) and obtained as a colorless oil (6.1 g, 92%). IR (neat): 3378
(br, OH) cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.25 (d, J = 8 Hz, 2H), 6.87
(d, J = 8 Hz, 2H), 4.43 (s, 2H), 3.80 (s, 3H), 3.62 (t, J = 7 Hz, 2H), 3.44 (t,
J = 7 Hz, 2H), 1.58 (m, 4H), 1.37 (m, 4H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 159.1, 130.7, 129.2, 113.7, 72.6, 70.0, 63.0, 55.3, 32.7, 29.7, 26.0,
25.6 ppm.
General procedure for the synthesis of compounds 15a-e. DDQ (1 eq.)
was added to a solution of 14a-e (1 eq.) in CH2Cl2/H2O. The resulting
mixture was stirred at room temperature for 1 h, then filtered on SiO2
(CH2Cl2/EtOAc, 9:1) and concentrated. Column chromatography (SiO2,
CH2Cl2 /MeOH) gave the corresponding 15a-e.
Compound 13d. Prepared from 12d (10.0 g, 76 mmol), PMB-Cl (4.1 ml,
30.1 mmol) and obtained as a colorless oil (6.9 g, 90%). IR (neat): 3378
(br, OH) cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.26 (d, J = 8 Hz, 2H), 6.87
(d, J = 8 Hz, 2H), 4.43 (s, 2H), 3.80 (s, 3H), 3.63 (t, J = 7 Hz, 2H), 3.43 (t,
J = 7 Hz, 2H), 1.58 (m, 4H), 1.34 (m, 6H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 159.1, 130.7, 129.2, 113.7, 72.5, 70.1, 63.0, 55.3, 32.7, 29.7, 29.2,
26.0, 25.7 ppm.
Compounds 15a. Prepared from 14a (5.25 g, 9.4 mmol) and obtained as
a colorless oil (1.94 g, 47%). IR (neat): 3403 (br, OH) cm-1. 1H NMR (400
MHz, CDCl3): δ = 7. 25 (d, J = 8 Hz, 2H), 6.87 (d, J = 8 Hz, 2H), 4.44 (s,
2H), 3.82 (m, 4H), 3.80 (s, 3H), 3.66 (t, J = 6 Hz, 2H), 3,47 (t, J = 6 Hz,
2H), 1,63 (m, 8H), 1.00 (s, 18H) ppm. 13C NMR (100 MHz, CDCl3): δ =
159.1, 130.7, 129.2, 113.7, 72.5, 70.0, 63.8, 63.7, 55.3, 29.9, 29.6, 27.9,
26.2, 21.2 ppm.
Compound 13e. Prepared from 12e (13.8 g, 94 mmol), PMB-CL (4.3 ml,
31.6 mmol) and obtained as a colorless oil (5.8 g, 69%). IR (neat): 3400
(br, OH) cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.26 (d, J = 8 Hz, 2H), 6.87
(d, J = 8 Hz, 2H), 4.43 (s, 2H), 3.80 (s, 3H), 3.63 (t, J = 7 Hz, 2H), 3.43 (t,
J = 7 Hz, 2H), 1.57 (m, 4H), 1.32 (m, 8H) ppm. 13C NMR (100 MHz, CDCl3):
Compounds 15b. Prepared from 14b (6.00 g, 10.2 mmol) and obtained
as a colorless oil (2.26 g, 47%). IR (neat): 3399 (br, OH) cm-1. 1H NMR
(400 MHz, CDCl3): δ = 7.25 (d, J = 8 Hz, 2H), 6.87 (d, J = 8 Hz, 2H), 4.43
(s, 2H), 3.81 (m, 7H), 3.63 (t, J = 7 Hz, 2H), 3.44 (t, J = 7, 2H), 1.59 (m,
10
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10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
8H), 1.43 (m, 4H), 1.00 (s, 18H) ppm. 13C NMR (100 MHz, CDCl3): δ =
159.1, 130.7, 129.2, 113.7, 72.5, 70.2, 63.7, 63.6, 62.9, 55.3, 32.8, 32.6,
32.5, 29.6, 27.9, 22.5, 22.0, 21.2 ppm.
CDCl3): δ = 166.6, 159.1, 130.8, 129.1, 113.7, 72.5, 70.2 , 65.6, 63.8, 63.7,
55.3, 41.6, 32.9, 32.8, 29.8, 29.3, 29.0, 28.5, 28.0, 26.3, 25.8, 25.7, 21.2
ppm.
Compounds 15c. Prepared from 14c (3.1 g, 5.0 mmol) and obtained as
colorless oil (1.2 g, 48%). IR (neat): 3394 (br, OH) cm-1. 1H NMR (400 MHz,
CDCl3): δ = 7.25 (d, J = 8 Hz, 2H), 6.87 (d, J = 8 Hz, 2H), 4.43 (s, 2H),
3.81(m, 7H), 3.63 (t, J = 7 Hz, 2H), 3.44 (t, J = 7 Hz, 2H), 1.57 (m, 8H),
1.39 (m, 8H), 0.99 (s, 18H) ppm. 13C NMR (100 MHz, CDCl3): δ = 159.1,
130.7, 129.2, 113.7, 72.6, 70.2, 63.8, 63.7, 63.0, 55.3, 32.8 (three peaks),
29.8, 27.9, 26.0, 25.8, 25.7, 25.6, 21.2 ppm.
Compound 16e. Prepared from 15e (2.30 g, 4.1 mmol), malonyl chloride
(0.29 g, 2.0 mmol) and obtained as a colorless oil (2.18 g, 90%). IR (neat):
1753 (C=O), 1736 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.25 (d, J
= 8 Hz, 4H), 6.87 (d, J = 8 Hz, 4H), 4.43 (s, 4H), 4.13 (t, J = 7 Hz, 4H), 3.80
(s, 6H), 3.79 (t, J = 6 Hz, 8H), 3.43 (t, J = 6 Hz, 4H), 3.36 (s, 2H), 1.66 –
1.50 (m, 16H), 1.32 (m, 32H), 0.99 (s, 36H) ppm. 13C NMR (100 MHz,
CDCl3): δ = 166.7, 159.0, 130.8, 129.2, 113.7, 72.5, 70.2, 65.7, 63.8 (two
peaks), 55.3, 41.7, 32.9, 29.8, 29.5, 29.4, 29.3, 29.2, 28.7, 27.5, 26.2, 25.8,
21.2 ppm.
Compounds 15d. Prepared from 14d (5.7 g, 8.9 mmol) and obtained as
colorless oil (2.37 g, 51%). IR (neat): 3380 (br, OH) cm-1. 1H NMR (400
MHz, CDCl3): δ = 7.26 (d, J = 8 Hz, 2H), 6.87 (d, J = 8 Hz, 2H), 4.43 (s,
2H), 3.80 (m, 7H), 3.63 (t, J = 6 Hz, 2H), 3.43 (t, J = 6 Hz, 2H), 1.55 (m,
8H), 1.35 (m, 12H), 0.99 (s, 18H) ppm. 13C NMR (100 MHz, CDCl3): δ =
159.1, 130.7, 129.2, 113.7, 72.5, 70.2, 63.8 (two peaks), 63.0, 55.3, 32.8
(two peaks), 32.8, 29.8, 29.3 (two peaks), 27.9, 27.5, 26.3, 25.8, 21.2 ppm.
General procedure for the deprotection of compounds 17a-e. DDQ
(2.5 eq.) was added to a solution of 16a-e (1 eq.) in CH2Cl2/H2O (18:1).
The resulting mixture was stirred at room temperature for 2 h, then filtered
on SiO2 (CH2Cl2/MeOH, 95:5) and concentrated. Column chromatography
(SiO2, CH2Cl2/MeOH) gave 17a-e.
Compounds 15e. Prepared from 14e (5.4 g, 8.1 mmol) and obtained as a
colorless oil (2.22 g, 50%). IR (neat): 3388 (br, OH) cm-1. 1H NMR (400
MHz, CDCl3): δ = 7.27 (d, J = 8 Hz, 2H), 6.87 (d, J = 8 Hz, 2H), 4.43 (s,
2H), 3.80 (m, 7H), 3.63 (t, J = 6 Hz, 2H), 3.43 (t, J = 6 Hz, 2H), 1.55 (m,
8H), 1.33 (m, 16H), 0.99 (s, 18H) ppm. 13C NMR (100 MHz, CDCl3): δ =
159.1, 130.7, 129.2, 113.7, 72.5, 70.2, 63.8, 63.1, 55.3, 32.9, ppm 32.8,
29.8, 29.5, 29.4 (two peaks), 27.9, 27.5, 26.2, 25.8, 25.7, 21.2 ppm.
Compound 17a. Prepared from 16a (1.30 g, 1.37 mmol) and obtained as
a colorless oil (0.68 g, 68%). IR (neat): 3388 (br, OH), 1752 (C=O), 1737
(C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 4.21 (t, J = 7Hz, 4H), 3.88 (m,
8H), 3.70 (t, J = 6 Hz, 4H), 3.40 (s, 2H), 1.80 (m, 4H), 1.73–1.61 (m, 12H),
1.03 (s, 36H) ppm. 13C NMR (100 MHz, CDCl3): δ = 166.7, 65.5, 63.9, 63.2,
62.8, 41.6, 29.8, 29.6, 29.1, 27.9, 25.1, 21.2 ppm.
Compound 17b. Prepared from 16b (2.30 g, 2.3 mmol) and obtained as
a colorless oil (1.42 g, 81%). IR (neat): 3361 (br, OH), 1753 (C=O), 1736
(C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 4.15 (t, J = 7 Hz, 4H), 3.82 (2t,
J = 6 Hz, 8H), 3.65 (t, J = 7 Hz, 4H), 3.36 (s, 2H), 1.69 (m, 4H), 1.60 (m,
12H), 1.47 (m, 8H), 0.99 (s, 36H) ppm. 13C NMR (100 MHz, CDCl3): δ =
166.7, 65.6, 63.7, 63.4, 62.9, 41.6, 32.6, 32.5, 32.4, 28.2, 27.9, 22.1, 22.0,
21.2 ppm.
General procedure for the synthesis of compounds 16a-e. Malonyl
chloride (1 eq.) was added to a solution of 15a-e (2 eq.) and DMAP (2.2
eq) in CH2Cl2. The resulting mixture was stirred at room temperature for 2
h, then filtered on SiO2 (CH2Cl2/EtOAc, 9:1) and concentrated. Column
chromatography (SiO2, CH2Cl2/EtOAc) gave 16a-e.
Compound 16a. Prepared from 15a (1.9 g, 4.3 mmol), malonyl chloride
(0.3 g, 2.2 mmol) and obtained as a colorless oil (1.4 g, 67%). IR (neat):
1752 (C=O), 1735 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.25 (d, J
= 8 Hz, 4H), 6.87 (d, J = 8 Hz, 4H), 4.43 (s, 4H), 4.17 (t, J = 6 Hz, 4H), 3.82
(t, J = 6 Hz, 8H), 3.80 (s, 6H), 3.47 (t, J = 6 Hz, 4H), 3.37 (s, 2H), 1.77–
1.59 (m, 18H), 0.97 (s, 36H) ppm. 13C NMR (100 MHz, CDCl3): δ = 166.1,
159.1, 130.7, 129.2, 113.7, 72.5, 70.0, 65.5, 63.6, 63.1, 55.3, 41.6, 29.6,
29.1, 27.9, 26.3, 25.15, 21.2 ppm.
Compound 17c. Prepared from 16c (1.10 g, 1.0 mmol) and obtained as a
colorless oil (0.69 g, 80%). IR (neat): 3363 (br, OH), 1753 (C=O), 1737
(C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 4.14 (t, J = 7 Hz, 4H), 3.81 (2t,
J = 6 Hz, 8H), 3.66 (t, J = 6 Hz, 4H), 3.37 (s, 2H), 1.66 (m, 4H), 1.60 – 1.50
(m, 12H), 1.40 (m, 16H), 0.99 (s, 36H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 166.7, 65.6, 63.7, 63.6, 62.9, 41.6, 32.8 (three peaks), 28.5, 27.9, 25.6
(three peaks), 25.5, 21.2 ppm.
Compound 16b. Prepared from 15b (2.30 g, 4.8 mmol), malonyl chloride
(0.33 g, 2.4 mmol) and obtained as a colorless oil (2.24 g, 94%). IR (neat):
1753 (C=O), 1736 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.25 (d, J
= 8 Hz, 4H), 6.87 (d, J = 8 Hz, 4H), 4.43 (s, 4H), 4.14 (t, J = 7 Hz, 4H), 3.80
(s, 6H), 3.79 (t, J = 7 Hz, 8H), 3.45 (t, J = 7 Hz, 4H), 3.35 (s, 2H), 1.69 –
1.50 (m, 16H), 1.38 (m, 8H), 0.99 (s, 36H) ppm. 13C NMR (100 MHz,
CDCl3): δ = 166.6, 159.0, 130.7, 129.1, 113.7, 72.5, 70.2, 65.6, 63.7, 63.4,
55.3, 41.6, 32.9, 32.7, 29.8, 28.5, 27.9, 26.1, 25.7, 25.6, 25.5, 21.2 ppm.
Compound 17d. Prepared from 16d (2.30 g, 2.0 mmol) and obtained as
a colorless oil (1.52 g, 84%). IR (neat): 3378 (br, OH), 1756 (C=O) 1732
(C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 4.14 (t, J = 7 Hz, 4H), 3.80 (2t,
J = 6 Hz, 8H), 3.64 (t, J = 6 Hz, 4H), 3.37 (s, 2H), 1.65 (m, 4H), 1.56 (m,
16H), 1.35 (m, 20H), 0.99 (s, 36H) ppm. 13C NMR (100 MHz, CDCl3): δ =
166.7, 65.7, 63.8, 63.7, 63.0, 41.7, 32.9, 32.8 (two peaks), 29.4 (two
peaks), 29.3, 29.0, 28.4, 27.9, 25.8 (two peaks), 25.7, 21.2 ppm.
Compound 17e. Prepared from 16e (2.00 g, 1.7 mmol) and obtained as a
colorless oil (1.36 g, 85%). IR (neat): 3378 (br, OH), 1756 (C=O), 1732
(C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 4.13 (t, J = 7 Hz, 4H), 3.80 (t,
J = 6 Hz, 8H), 3.64 (t, J = 6 Hz, 4H), 3.36 (s, 2H), 1.64 (m, 4H), 1.55 (m,
16H), 1.33 (m, 28H), 0.99 (s, 36H) ppm. 13C NMR (100 MHz, CDCl3): δ =
166.7, 65.7, 63.8 (two peaks), 63.0, 41.7, 32.9, 32.8, 29.4 (two peaks),
29.3, 29.2, 28.4, 27.9, 27.5, 25.7 (two peaks), 21.2 ppm.
Compound 16c. Prepared from 15c (1.20 g, 2.3 mmol), malonyl chloride
(0.16 g, 1.2 mmol) and obtained as a colorless oil (1.13 g, 93%). IR (neat):
1753 (C=O), 1736 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.25 (d, J
= 8 Hz, 4H), 6.87 (d, J = 8 Hz, 4H), 4.43 (s, 4H), 4.14 (t, J = 7 Hz, 4H), 3.80
(s, 6H), 3.79 (t, J = 6 Hz, 8H), 3.44 (t, J = 6 Hz, 4H), 3.36 (s, 2H), 1.69 –
1.50 (m, 18H), 1.38 (m, 14H), 0.99 (s, 36H) ppm. 13C NMR (100 MHz,
CDCl3): δ = 166.6, 159.0, 130.7, 129.2, 113.7, 72.5, 70.2, 65.6, 63.8, 63.6,
55.3, 41.6, 32.7, 32.4, 29.6, 28.3, 27.9, 22.5, 22.1, 21.2 ppm.
General procedure for the synthesis of macrocycles 18a-e. A solution
of DMAP (2.2 eq.) in CH2Cl2 was added dropwise to a solution of 17a-e (1
eq.) and malonyl chloride (1.1 eq.) in CH2Cl2. The resulting mixture was
stirred at room temperature for 2 h, then filtered (SiO2, CH2Cl2/EtOAc 9:1)
and concentrated. Column chromatography (SiO2, CH2Cl2/EtOAc 97:3)
gave the corresponding macrocycles 18a-e.
Compound 16d. Prepared from 15d (2.30 g, 4.3 mmol), malonyl chloride
(0.31 g, 2.2 mmol) and obtained as a colorless oil (2.36 g, 96%). IR (neat):
1753 (C=O), 1736 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.26 (d, J
= 8 Hz, 4H), 6.87 (d, J = 8 Hz, 4H), 4.43 (s, 4H), 4.13 (t, J = 7 Hz, 4H), 3.80
(s, 6H), 3.79 (t, J = 6 Hz, 8H), 3.43 (t, J = 6 Hz, 4H), 3.36 (s, 2H), 1.66 –
1.51 (m, 16H), 1.35 (m, 24H), 0.99 (s, 36H) ppm. 13C NMR (100 MHz,
11
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10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
Compound 18a. Prepared from 17a (0.67 g, 0.94 mmol) and obtained as
a colorless oil (367 mg, 50%). IR (neat): 1736 (C=O) cm-1. 1H NMR (400
MHz, CDCl3): δ = 4.15 (t, J = 7 Hz, 8H), 3.81 (t, J = 7 Hz, 8H), 3.34 (s, 4H),
1.73 (m, 8H), 1.59 (m, 8H), 0.96 (s, 36H) ppm. 13C NMR (100 MHz, CDCl3):
δ = 166.6, 65.4, 63.1, 41.7, 29.2, 27.8, 25.1, 21.2 ppm. MALDI-TOF-MS:
m/z = 799.46 (100%, [M+Na]+, calcd for C38H72O12Si2Na: 799.45), 777.38
(24%, [M+H]+, calcd for C38H73O12Si2: 777.46), 815.38 (20%, [M+K]+, calcd
for C38H72O12Si2K: 815.42).
peaks), 69.4, 68.8, 65.3, 65.1, 51.3, 27.9 (two peaks), 26.9, 21.6, 21.4 ppm.
MALDI-TOF-MS: m/z = 1686.7 ([M+H]+, calcd for C114H69O12Si2: 1686.9).
Compound 20. Prepared from 7b (0.170 g, 0.14 mmol) and obtained as a
red-brown glassy product (42 mg, 15%). UV/Vis (CH2Cl2): lmax(e) = 254
(119500), 311 (sh, 47000), 397 (4700), 409 (sh, 3000), 421 (2800), 478
(3200), 622 nm (sh, 450 M-1cm-1). IR (neat): 1751 (C=O) cm-1. 1H NMR
(400 MHz, CDCl3): d = 7.41 (d, 3J = 8 Hz, 2H), 7.35 (d, 3J = 8 Hz, 2H), 7.33
(d, 3J = 8 Hz, 2H), 7.28 (d, 3J = 8 Hz, 2H), 7.26 (d, 3J = 8 Hz, 2H), 7.21 (d,
3J = 8 Hz, 2H), 7.04 (d, 3J = 8 Hz, 2H), 6.98 (d, 3J = 8 Hz, 2H), 5.73 (d, 2J
= 11 Hz, 1H), 5.67 (d, 2J = 11 Hz, 1H), 5.61 (d, 2J = 12 Hz, 1H), 5.49 (d, 2J
= 12 Hz, 1H), 5.37 (d, 2J = 12 Hz, 1H), 5.19 (d, 2J = 12 Hz, 1H), 5.11 (d, 2J
= 11 Hz, 1H), 5.00 (d, 2J = 11 Hz, 1H), 4.84 (s, 2 H), 4.77 (s, 2H), 4.65 (d,
2J = 13 Hz, 1H), 4.58 (d, 2J = 13 Hz, 1H), 4.56 (s, 2H), 1.06-0.80 (m, 56H)
ppm. 13C NMR (100 MHz, CDCl3): d = 163.6, 163.5, 163.3, 162.6, 148.1,
147.3, 147.2, 147.1, 146.4 (two peaks), 146.2, 146.1, 145.9, 145.5 (two
peaks), 145.3, 145.2, 144.9, 144.8, 144.7, 144.6 (two peaks), 144.5 (two
peaks), 144.4, 144.3 (three peaks), 144.0, 143.9, 143.8, 143.7, 143.6,
143.5, 143.4, 143.3 (two peaks), 143.1 (two peaks), 142.9, 142.8 (two
peaks), 142.5, 142.3, 142.2, 142.1, 142.0 (three peaks), 141.9, 141.8,
141.5 (two peaks), 141.3, 141.0, 140.7, 138.9, 138.8, 138.3, 138.2, 133.9,
133.3, 132.7, 132.5, 129.9, 129.0, 128.7, 128.5, 126.7, 126.1, 125.9, 125.5,
71.4, 71.3 (two peaks), 69.7, 68.9, 68.8 (two peaks), 68.7, 64.4, 63.9, 63.8,
63.5, 53.7, 51.0, 17.4 (two peaks), 17.3 (four peaks), 17.2 (three peaks),
13.1, 13.0 (two peaks), 12.9 (two peaks), 12.8 ppm. MALDI-TOF-MS: m/z
= 1889.3 ([M]+, calcd for C122H88O14Si4: 1889.5).
Compound 18b. Prepared from 17b (1.40 g, 1.83 mmol) and obtained as
a colorless oil (430 mg, 28%). IR (neat): 1752 (C=O), 1734 (C=O) cm-1. 1H
NMR (400 MHz, CDCl3): δ = 4.15 (t, J = 7 Hz, 8H), 3.81 (t, J = 7 Hz, 8H),
3.36 (s, 4H), 1.68 (m, 8H), 1.58 (m, 8H), 1.45 (m, 8H), 0.99 (s, 36H) ppm.
13C NMR (100 MHz, CDCl3): δ = 166.6, 65.5, 63.5, 41.7, 32.4, 28.3, 27.9,
22.1, 21.2 ppm. MALDI-TOF-MS: m/z = 833.37 (100%, [M+H]+, calcd for
C42H81O12Si2: 833.53), 855.51 (61%, [M+Na]+, calcd for C42H80O12Si2Na:
855.51).
Compound 18c. Prepared from 17c (0.66 g, 0.8 mmol) and obtained as a
colorless oil (215 mg, 30%). IR (neat): 1753 (C=O), 1735 (C=O) cm-1. 1H
NMR (400 MHz, CDCl3): δ = 4.15 (t, J = 7 Hz, 8H), 3.80 (t, J = 7 Hz, 8H),
3.36 (s, 4H), 1.66 (m, 8H), 1.56 (m, 8H), 1.39 (m, 16H), 0.99 (s, 36H) ppm.
13C NMR (100 MHz, CDCl3): δ = 166.6, 65.5, 63.6, 41.8, 32.7, 28.5, 27.9,
25.6, 25.4, 21.2 ppm. MALDI-TOF-MS: m/z = 889.73 ([M+H]+, calcd for
C46H89O12Si2: 889.59).
Compound 18d. Prepared from 17d (1.47 g, 1.68 mmol) and obtained as
a colorless oil (303 mg, 19%). IR (neat): 1752 (C=O), 1736 (C=O) cm-1. 1H
NMR (400 MHz, CDCl3): δ = 4.14 (t, J = 7 Hz, 8H), 3.80 (t, J = 7 Hz, 8H),
3.36 (s, 4H), 1.65 (m, 8H), 1.55 (m, 8H), 1.35 (m, 24H), 1.00 (s, 36H) ppm.
13C NMR (100 MHz, CDCl3): δ = 166.6, 65.6, 63.7, 41.8, 32.8, 29.0, 28.4,
25.8, 25.7, 21.1 ppm. MALDI-TOF-MS: m/z = 967.68 (100%, [M+Na]+,
calcd for C50H96O12Si2Na: 967.63), 983.60 (28%, [M+K]+, calcd for
C50H96O12Si2K: 983.61), 945.57 (26%, [M]+, calcd for C50H96O12Si2:
945.65).
Compound 21. Prepared from 7b (0.170 g, 0.14 mmol) and obtained as a
brown glassy product (72 mg, 26%). UV/Vis (CH2Cl2): lmax(e) = 251
(113700), 323 (sh, 36100), 399 (sh, 5000), 412 (3900), 423 (3200), 486
2600), 582 (sh, 1100), 639 (sh, 430), 692 nm (sh, 150 M-1cm-1). IR (neat):
1747 (C=O), 1728 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): d = 7.44 (d, 3J
= 8 Hz, 4H), 7.28 (d, 3J = 8 Hz, 4H), 7.26 (d, 3J = 8 Hz, 4H), 7.14 (d, 3J =
8 Hz, 4H), 5.77 (d, 2J = 11 Hz, 2H), 5.43 (d, 2J = 11 Hz, 2H), 5.40 (d, 2J =
11 Hz, 2H), 5.30 (d, 2J = 11 Hz, 2H), 4.80 (d, 2J = 13 Hz, 2H), 4.76 (d, 2J =
13 Hz, 2H), 4.72 (d, 2J = 13 Hz, 2H), 4.68 (d, 2J = 13 Hz, 2H), 1.05-0.97
(m, 56H) ppm. 13C NMR (100 MHz, CDCl3): d = 163.8, 163.3, 146.8, 146.3
(three peaks), 145.8, 145.4, 145.3, 145.2, 145.1, 145.0, 144.9, 144.6 (two
peaks), 144.4, 144.1, 144.0, 143.8, 143.6, 143.4, 143.2, 143.1, 143.0,
142.8, 142.6, 142.5 (two peaks), 142.1, 142.0, 141.9, 141.7, 141.4, 141.2,
140.7, 139.6, 138.8 (two peaks), 137.9, 133.3, 132.9, 132.7, 130.9, 130.3,
129.8, 126.1, 126.0, 125.9, 71.0, 70.9, 69.3, 68.9, 64.1, 63.9, 51.4, 17.4
(two peaks), 17.3, 13.0, 12.9 (two peaks) ppm. MALDI-TOF-MS: m/z =
1890.3 ([M+H]+, calcd for C122H89O14Si4: 1890.5).
Compound 18e. Prepared from 17e (1.30 g, 1.39 mmol) and obtained as
a colorless oil (270 mg, 19%). IR (neat): 1752 (C=O), 1736 (C=O) cm-1. 1H
NMR (400 MHz, CDCl3): δ = 4.14 (t, J = 7 Hz, 8H), 3.80 (t, J = 7 Hz, 8H),
3.36 (s, 4H), 1.73 (m, 8H), 1.64 (m, 8H), 1.55 (m, 32H), 1.00 (s, 36H) ppm.
13C NMR (100 MHz, CDCl3): δ = 166.6, 65.6, 63.8, 41.8, 32.9, 29.3, 29.2,
28.5, 27.9, 25.7, 25.7, 21.2 ppm. MALDI-TOF-MS: m/z = 1023.72 (100%,
[M+Na]+, calcd for C54H104O12Si2Na: 1023.70), 1039.69 (30%, [M+K]+,
calcd for C54H104O12Si2K: 1039.67), 1000.63 (12%, [M]+, calcd for
C54H104O12Si2: 1000.71).
Compound 22. Prepared from 11b (0.170 g, 0.13 mmol) and obtained as
a red-brown glassy product (40 mg, 15%). UV/Vis (CH2Cl2): lmax (ɛ) = 253
(130000), 324 (sh, 23100), 399 (sh, 5100), 412 (4000), 423 (3100), 488
(2700), 579 (sh, 1100), 633 (sh, 460), 691 nm (sh, 140 M-1cm-1). IR (neat):
General procedure for the functionalization of C60. DBU (5 eq.) was
added to a solution of C60 (1 eq.), macrocycle bis-malonate (4b, 7b, 11b
or 18a-e, 1 eq.) and I2 (2.5 eq.) in toluene (2 ml/mg of C60). The resulting
mixture was stirred at rt for 1 h, then filtered through a plug (SiO2, toluene
then CH2Cl2) and concentrated. Column chromatography (SiO2,
CH2Cl2/cyclohexane) gave the corresponding bis-adducts 19-24, 25a,
26b-e and 27b-e.
3
1749 (C=O), 1728 (C=O) cm-1.1H NMR (400 MHz, CDCl3): δ = 7.57 (d, J
3
= 8 Hz, 4H), 7.52 (d, 3J = 8 Hz, 4H), 7.41 (s, 8H), 7.38 (d, J = 8 Hz, 4H),
7.33 (d, 3J = 8 Hz, 4H), 7.21 (d, 3J = 8 Hz, 4H), 7.13 (d, 3J = 8 Hz, 4H),
5.73 (d, 2J = 12 Hz, 2H), 5.63 (d, 2J = 12 Hz, 2H), 5.49 (d, 2J = 12 Hz, 2H),
5.40 (d, 2J = 12 Hz, 2H), 4.83 (d, 2J = 14 Hz, 2H), 4.80 (d, 2J = 14 Hz, 2H),
4.71 (d, 2J = 13 Hz, 2H), 4.65 (d, 2J = 13 Hz, 2H), 1.14 (s, 18H), 1.10 (s,
18H) ppm. 13C NMR (100 MHz, CDCl3): δ = 163.5, 163.4, 146.8, 146.6,
146.2, 146.1, 145.1, 145.8, 145.7, 145.6, 145.5, 145.4, 145.1, 145.0, 144.4,
144.1, 143.7, 143.5, 143.3, 143.2, 143.1, 142.5, 142.2, 142.0, 141.9, 141.8
(two peaks), 141.6, 141.3, 140.5, 140.0, 139.3, 139.0, 138.8, 137.8, 133.5,
133.2, 130.4, 129.9, 127.4, 127.1, 126.9, 126.8 (two peaks), 126.4, 71.4,
70.9, 69.1, 68.9, 65.5, 65.3, 51.7, 28.2, 28.1, 21.3, 21.2 ppm. MALDI-TOF-
MS: m/z = 1990.3 ([M+H]+, calcd for C138H85O12Si2: 1990.5).
Compound 19. Prepared from 4b (0.190 g, 0.20 mmol) and obtained as a
brown glassy product (0.179 g, 54%). UV/Vis (CH2Cl2) lmax (ɛ) = 252
(124500), 322 (sh, 39900), 399 (sh, 5200), 412 (4100), 423 (3400), 491
(2800), 579 (sh, 1200), 635 (sh, 500), 687 nm (sh, 159 M-1cm-1). IR (neat):
1748 (C=O), 1729 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.47 (d, 3J
= 8 Hz, 4H), 7.26 (d, 3J = 8 Hz, 8H), 7.13 (d, 3J = 8 Hz, 4H), 5.78 (d, 2J =
11 Hz, 2H), 5.46 (d, 2J = 11 Hz, 2H), 5.35 (d, 2J = 11 Hz, 2H), 5.33 (d, 2J =
11 Hz, 2H), 4.91 (d, 2J = 14 Hz, 2H), 4.88 (d, 2J = 14 Hz, 2H), 4.77 (d, 2J =
14 Hz, 2H), 4.72 (d, 2J = 14 Hz, 2H), 1.07 (s, 36H) ppm. 13C NMR (100
MHz, CDCl3): δ = 163.8, 163.2, 146.7, 146.5, 146.3 (two peaks), 145.7,
145.3, 145.2, 145.1, 144.8, 144.6, 144.5, 144.4, 144.1, 143.8, 143.6, 143.2,
143.0, 142.9, 142.6, 142.3, 142.1, 142.0, 141.8, 141.6, 141.3, 141.0, 139.3,
138.6, 137.9, 133.3, 132.6, 130.6, 130.3, 125.6 (two peaks), 70.9 (two
Compound 23. Prepared from 11b (0.170 g, 0.13 mmol) and obtained as
a red-brown glassy product (12 mg, 4%). UV/Vis (CH2Cl2): lmax (ɛ) = 255
(126000), 317 (sh, 27000), 397 (sh, 4500), 410 (sh, 2800), 422 (2600),
479 (sh, 3000), 620 nm (sh, 410 M-1cm-1). IR (neat): 1747 (C=O) cm-1. 1H
NMR (400 MHz, CDCl3): d = 7.57-7.42 (m, 16H), 7.37-7.26 (m, 8H), 7.20
12
This article is protected by copyright. All rights reserved.

10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
(m, 4H), 7.04 (d, 3J = 8 Hz, 2H), 6.99 (d, 3J = 8 Hz, 2H), 5.85 (d, 2J = 11
Hz, 1H), 5.77 (d, 2J = 12 Hz, 1H), 5.60 (d, 2J = 12 Hz, 1H), 5.59 (d, 2J = 11
Hz, 1H), 5.47 (d, 2J = 12 Hz, 1H), 5.33 (d, 2J = 11 Hz, 1H), 5.17 (d, 2J = 11
Hz, 1H), 5.07 (d, 2J = 12 Hz, 1H), 5.03 (AB, 2J = 12 Hz, 2H), 4.84 (d, 2J =
13 Hz, 1H), 4.74 (d, 2J = 13 Hz, 1H), 4.68 (AB, 2J = 12 Hz, 2H), 4.45 (d, 2J
= 13 Hz, 1H), 4.34 (d, 2J = 13 Hz, 1H), 1.15 (s, 18H), 1.10 (s, 18H) ppm.
13C NMR (100 MHz, CDCl3): d = 163.9, 163.7, 163.4, 162.6, 147.6, 147.4,
147.1 (two peaks), 146.4, 146.3 (two peaks), 146.2, 146.0, 145.9, 145.8,
145.5 (two peaks), 145.4, 145.2, 145.1, 145.0, 144.6 (two peaks), 144.5
(three peaks), 144.4, 144.3 (three peaks), 144.0 (two peaks), 143.7 (two
peaks), 143.6, 143.4, 143.3, 143.2 (two peaks), 143.0 (two peaks), 142.9,
142.8, 142.7, 142.5, 142.3, 142.2, 142.0, 141.9, 141.7, 141.6, 141.5, 141.4,
141.3, 141.0, 140.8, 140.7, 140.6, 140.5 (two peaks), 139.4, 138.8, 138.7,
138.4, 138.3, 138.1, 133.7, 133.4 (two peaks), 133.1, 130.9, 130.2, 129.0,
128.9, 127.5, 127.4, 127.3, 127.2, 127.1, 126.9, 126.8, 126.6 (two peaks),
126.4, 125.9, 71.4 (three peaks), 69.0, 68.9, 68.7, 68.6, 66.2, 65.7, 65.3,
65.1, 51.0, 48.3, 28.3, 28.2, 28.1 (two peaks), 21.4, 21.2 (two peaks) ppm.
Compound 27b. Prepared from 18b (0.430 g, 0.52 mmol) and obtained
as a red-brown glassy product (95 mg, 12%). UV/Vis (CH2Cl2): lmax (ɛ) =
248 (134100), 310 (sh, 47800), 356 (sh, 22000), 397 (5100), 409 (sh,
3100), 421 (3100), 480 (3800), 620 nm (sh, 500 M-1cm-1). IR (neat): 1744
(C=O) cm-1. 1H NMR (400 MHz, CDCl3): d = 4.73-4.53 (m, 4H), 4.36 (m,
2H), 4.25 (m, 2H), 3.88 (m, 2H), 3.83-3.66 (m, 5H), 3.54 (m, 1H), 1.77 (m,
8H), 1.66–1.50 (m, 16H), 1.00 (s, 18H), 0.97 (s, 9H) , 0.90 (s, 9H) ppm.
13C NMR (100 MHz, CDCl3): d = 164.3, 163.6, 163.0, 162.8, 149.0, 147.4,
147.2, 147.1, 146.6, 146.5, 146.3 (two peaks), 146.1, 146.0 (two peaks),
145.7, 145.6, 145.4 (two peaks), 145.1, 145.0, 144.9, 144.8, 144.7 (two
peaks), 144.6 (two peaks), 144.3 (two peaks), 144.1, 143.9 (two peaks),
143.8, 143.7 (two peaks), 143.5, 143.4, 143.3, 143.2, 143.1 (two peaks),
142.9, 142.4, 142.0, 141.7, 141.4, 141.2, 140.0, 139.9, 139.7, 139.5, 138.7,
138.4, 71.9, 71.8, 71.7, 70.4, 67.8, 67.4, 66.9, 64.3, 64.0, 63.4 (two peaks),
53.8, 53.1, 33.3, 32.8, 32.3, 32.2, 29.2, 28.3, 28.2, 27.9 (several peaks),
27.7, 23.5, 23.2, 22.3, 22.2, 21.3 (two peaks), 21.1 (two peaks) ppm.
MALDI-TOF-MS: m/z = 1571.82 ([M+Na]+, calcd for C102H76O12Si2Na:
1571.48).
Compound 24. Prepared from 11b (0.170 g, 0.13 mmol) and obtained as
an orange-brown glassy product (16 mg, 6%). UV/Vis (CH2Cl2): lmax (ɛ) =
250 (128000), 318 (sh, 39800), 389 (9500), 411 (sh, 5100), 439 (4500),
470 (3800), 621 nm (sh, 450 M-1cm-1). IR (neat): 1746 (C=O) cm-1. 1H
NMR (400 MHz, CDCl3): d = 7.42 (d, 3J = 8 Hz, 4H), 7.28 (d, 3J = 8 Hz, 4H),
7.20 (s, 8H), 7.18 (d, 3J = 8 Hz, 4H), 7.09 (d, 3J = 8 Hz, 4H), 7.06 (d, 3J =
8 Hz, 4H), 6.95 (d, 3J = 8 Hz, 4H), 5.70 (d, 2J = 12 Hz, 2H), 5.69 (d, 2J =
12 Hz, 2H), 5.35 (d, 2J = 12 Hz, 2H), 5.03 (s, 4H), 4.90 (d, 2J = 12 Hz, 2H),
4.83 (d, 2J = 13 Hz, 2H), 4.74 (d, 2J = 13 Hz, 2H), 1.23 (s, 9H), 1.21 (s, 9H),
1.18 (s, 9H), 1.15 (s, 9H) ppm. 13C NMR (100 MHz, CDCl3): d = 163.3,
162.4, 147.4, 146.2, 145.9 (two peaks), 145.7, 145.4, 145.3 (two peaks),
145.1, 145.0, 144.7, 144.6, 144.4, 144.2, 143.8, 143.6, 143.2, 142.5, 142.0,
141.0 (two peaks), 140.9, 140.5, 140.2, 139.4, 138.7 (two peaks), 138.4,
138.2, 137.5, 133.5, 133.4, 129.5, 128.3, 127.1, 127.0, 126.6 (three peaks),
126.5, 70.1, 68.6, 68.0, 67.7, 66.0, 65.6, 49.0, 28.5, 28.3, 28.2 (two peaks),
21.6, 21.5, 21.4, 21.2 ppm.
Compound 26c. Prepared from 18c (0.210 g, 0.24 mmol) and obtained
as a brown glassy product (125 mg, 33%). UV/Vis (CH2Cl2): lmax (ɛ) = 250
(147000), 318 (sh, 45000), 377 (sh, 13300), 399 (sh, 5300), 412 (4400),
423 (3600), 489 (3000), 573 (sh, 1400), 630 (sh, 600), 687 nm (sh, 200 M-
1cm-1). IR (neat): 1749 (C=O), 1727 (C=O) cm-1. 1H NMR (400 MHz,
CDCl3): d = 4.78 (m, 2H), 4.52 (m, 2H), 4.38 (m, 4H), 3.64 (m, 8H), 1.80
(m, 4H), 1.69 (m, 4H), 1.50-1.19 (m, 24H), 0.93 (s, 18H), 0.91 (s, 18H)
ppm. 13C NMR (100 MHz, CDCl3): d = 164.4, 163.8, 147.3, 147.2, 147.0,
146.9, 146.7 (two peaks), 146.5, 146.4 (two peaks), 145.8, 145.4, 145.3,
144.7, 144.4, 144.3, 144.0, 143.6 (two peaks), 143.0, 142.6, 142.0, 141.7
(two peaks), 141.6, 140.2, 139.0, 138.2, 71.7, 71.6, 67.5, 63.8, 63.7, 53.1,
33.0, 32.9, 29.7, 28.8, 28.7, 27.6, 26.5, 26.3, 25.6, 25.4, 21.2, 21.1 ppm.
MALDI-TOF-MS: m/z = 1627.56 ([M+Na]+, calcd for C106H84O12Si2Na:
1627.54).
Compound 27c. Prepared from 18c (0.210 g, 0.24 mmol) and obtained
as a red-brown glassy product (102 mg, 27%). UV/Vis (CH2Cl2): lmax (ɛ) =
252 (136000), 309 (sh, 52000), 356 (sh, 21400), 397 (5000), 409 (sh,
3100), 421 (3000), 480 (3700), 621 nm (sh, 450 M-1cm-1). IR (neat): 1745
(C=O) cm-1. 1H NMR (400 MHz, CDCl3): d = 4.72 (m, 1H), 4.57 (m, 3H),
4.33 (m, 2H), 4.16 (m, 2H), 3.80 (m, 7H), 3.71 (m, 1H), 1.77 (m, 8H), 1.64–
1.13 (m, 24H), 1.00 (s, 9H), 0.97 (s, 18H), 0.91 (s, 9H) ppm. 13C NMR (100
MHz, CDCl3): d = 163.7, 163.5, 163.2, 147.4, 147.2, 146.6, 146.4, 146.1,
145.7, 145.6, 145.4, 145.2, 144.8, 144.7, 144.6, 144.4, 144.1, 144.0, 143.9
(two peaks), 143.5 (two peaks), 143.3, 142.5, 142.1, 141.6 (two peaks),
140.6, 139.6 (two peaks), 138.6 (two peaks), 71.8, 67.7, 67.3, 66.9 (two
peaks), 64.2, 63.6, 63.4, 51.9, 33.2, 32.8, 32.7 (two peaks), 28.6, 28.2,
28.0, 27.9, 27.2, 26.9, 26.5, 26.1, 25.5, 25.2, 25.1 (two peaks), 25.0 (two
peaks), 21.1 (three peaks) ppm. MALDI-TOF-MS: m/z = 1627.65 (100%,
[M+Na]+, calcd for C106H84O12Si2Na: 1627.54), 1643.59 (30%, [M+K]+,
calcd for C106H84O12Si2K: 1643.51), 1605.61 (12%, [M]+, calcd. for
C106H85O12Si2: 1605.56).
Compound 25a. Prepared from 18a (0.286 g, 0.37 mmol) and obtained
as an orange-brown glassy product (212 mg, 39%). UV/Vis (CH2Cl2): lmax
(ɛ) = 259 (141000), 319 (sh, 43200), 380 (sh, 14100), 439 (3900), 470
(3400), 621 nm (sh, 420 M-1cm-1). IR (neat): 1746 (C=O) cm-1. 1H NMR
(400 MHz, CDCl3): d = 4.57 (m, 2H), 4.50 (m, 2H), 4.39 (m, 2H), 4.26 (m,
2 H), 3.95 (t, J = 4Hz, 4H), 3.85 (m, 4H), 1.99 (m, 4H), 1.84 (m, 4H), 1.75
(m, 4H), 1.63 (m, 4H), 1.07 (s, 9H), 1.04 (2s, 18H), 0.95 (s, 9H) ppm. 13C
NMR (100 MHz, CDCl3): d = 163.3, 163.2, 148.2, 147.4, 147.3 (two peaks),
146.8, 146.2, 146.0, 145.8, 145.7, 145.5, 145.3, 145.0 (two peaks), 144.7,
144.6, 144.4 (two peaks), 144.1, 143.6 (two peaks), 143.5, 142.5, 142.4,
141.3, 141.1, 140.1, 137.1, 136.4, 136.1, 135.6, 70.6, 67.7, 66.7 (two
peaks), 63.2, 62.8, 50.3, 28.8, 28.5, 27.9 (three peaks), 27.8, 26.9, 25.5,
25.0, 21.4, 21.3, 21.2 ppm. MALDI-TOF-MS: m/z = 1515.38 (100%,
[M+Na]+, calcd for C98H68O12Si2Na: 1515.41), 1493.33 (81%, [M+H]+, calcd
for C98H69O12Si2: 1493.43), 1531.36 (26%, [M+K]+, calcd for
C98H68O12Si2K: 1531.39).
Compound 26b. Prepared from 18b (0.430 g, 0.52 mmol) and obtained
as a brown glassy product (350 mg, 44%). UV/Vis (CH2Cl2): lmax (ɛ) = 250
(130800), 318 (sh, 40400), 377 (sh, 11000), 399 (sh, 5030), 412 (4100),
423 (3400), 490 (2900), 574 (sh, 1300), 628 (sh, 550), 684 nm (sh, 170 M-
1cm-1). IR (neat): 1749 (C=O), 1724 (C=O) cm-1. 1H NMR (400 MHz,
CDCl3): d = 4.81 (m, 2H), 4.57 (m, 2H), 4.40 (m, 4H), 3.62-2.52 (m, 8H),
1.90 (m, 2H), 1.75 (m, 6H), 1.50–1.34 (m, 16H), 0.93 (s, 18H), 0.92 (s,
18H) ppm. 13C NMR (100 MHz, CDCl3): d = 164.8, 163.4, 147.5 (two
peaks), 147.3, 147.2, 146.6, 146.4 (two peaks), 146.3, 145.5, 145.4, 145.1,
144.8, 144.4, 144.3, 144.0, 143.7, 143.6, 143.5, 142.7, 142.6, 142.0, 141.7,
141.1 (two peaks), 140.0, 139.6, 138.8, 71.7, 71.4, 68.2, 67.3, 64.2, 64.0,
53.4, 32.7, 32.5, 28.7, 27.9, 27.8, 26.9, 23.4, 21.1 (two peaks) ppm.
MALDI-TOF-MS: m/z = 1571.80 ([M+Na]+, calcd for C102H76O12Si2Na:
1571.48).
Compound 26d. Prepared from 18d (0.288 g, 0.30 mmol) and obtained
as a brown glassy product (102 mg, 20%). UV/Vis (CH2Cl2): lmax (ɛ) = 250
(132000), 318 (sh, 40700), 377 (sh, 11300), 399 (sh, 5200), 412 (4200),
423 (3500), 487 (2900), 573 (sh, 1300), 630 (sh, 500), 687 nm (sh, 150 M-
1cm-1). IR (neat): 1742 (C=O), 1728 (C=O) cm-1. 1H NMR (400 MHz,
CDCl3): d = 4.77 (m, 2H), 4.43 (m, 6H), 3.66 (m, 8H), 1.82 (m, 4H), 1.70
(m, 4H), 1.50–1.19 (m, 32H), 0.93 (s, 36H) ppm. 13C NMR (100 MHz,
CDCl3): d = 163.9 (two peaks), 147.2, 147.0, 146.8, 146.6 (two peaks),
146.5, 146.4, 146.3 (two peaks), 146.0, 145.5, 145.4, 144.6, 144.3, 144.2,
143.9, 143.6, 143.4, 142.9, 142.5, 142.2 (two peaks), 141.9, 141.6, 140.3,
138.5, 137.8, 71.9, 71.6, 67.5, 67.3, 63.8, 63.7, 53.0, 32.8, 32.7, 29.0, 28.8,
28.7, 28.6, 27.9 (two peaks), 26.4, 26.0, 25.9, 25.6, 21.1 (two peaks) ppm.
MALDI-TOF-MS: m/z = 1663.44 ([M+H]+, calcd for C110H93O12Si2: 1663.08),
1683.61 ([M+Na]+, calcd for C110H92O12Si2Na: 1683.60).
13
This article is protected by copyright. All rights reserved.

10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
Compound 27d. Prepared from 18d (0.288 g, 0.30 mmol) and obtained
as a red-brown glassy product (150 mg, 30%). UV/Vis (CH2Cl2): lmax (ɛ) =
253 (135300), 309 (sh, 52000), 356 (sh, 20400), 397 (5300), 409 (sh,
3300), 421 (3050), 480 (3800), 619 nm (sh, 530 M-1cm-1). IR (neat): 1747
(C=O) cm-1. 1H NMR (400 MHz, CDCl3): d = 4.68–4.46 (m, 4H), 4.35–4.19
(m, 4H), 3.82–3.74 (m, 6H), 3.67 (m, 2H), 1.76 (m, 8H), 1.53 (m, 8H), 1.49-
1.13 (m, 24H), 0.99 (s, 9H), 0.98 (s, 9H), 0.97 (s, 9H), 0.93 (s, 9H) ppm.
13C NMR (100 MHz, CDCl3): d = 163.9, 163.6, 163.5, 163.3, 148.6, 147.5,
147.3, 147.2, 146.5 (two peaks), 146.4, 146.2, 146.1 (two peaks), 146.0,
145.6, 145.5, 145.2, 145.1 (two peaks), 145.0 (two peaks), 144.8, 144.7
(two peaks), 144.6 (three peaks), 144.5, 144.3 (two peaks), 144.1, 144.0,
143.8 (two peaks), 143.7 (three peaks), 143.5, 143.3 (two peaks), 143.0
(two peaks), 142.7, 142.3, 142.3, 142.2, 142.1, 141.9 (two peaks), 141.6,
141.5, 141.1, 140.8, 139.3, 138.6 (two peaks), 71.8, 70.4, 67.4, 67.3, 67.2,
63.9 (two peaks), 63.7, 63.6, 53.8, 51.9, 33.1, 32.8, 32.8, 32.7, 32.3, 29.5,
29.0, 28.7, 28.6 (two peaks), 28.4 (two peaks), 28.2, 27.9 (two peaks),
26.8, 26.0, 25.9, 25.8, 25.7, 25.5, 25.4, 21.2, 21.1 (two peaks) ppm.
MALDI-TOF-MS: m/z = 1683.61 ([M+Na]+, calcd for C110H92O12Si2Na:
1683.60), 1663.64 ([M+H]+, calcd for C110H93O12Si2: 1663.08).
145.1, 145.0, 144.7, 144.4 (two peaks), 144.2, 143.7, 143.6, 143.4, 142.5,
142.4, 141.3, 141.0, 139.7, 137.8, 137.1, 136.7, 135.2, 70.5, 67.7, 67.1,
62.2, 62.1, 49.6, 29.2, 29.1, 25.1, 25.0 ppm. MALDI-TOF-MS: m/z =
1212.44 ([M]+, calcd for C82H36O12: 1212.22).
Compound 29b. Prepared from 26b (118 mg, 76 μmol) and obtained as
a brown glassy product (78 mg, 81%). UV/Vis (CH2Cl2): lmax (ɛ) = 249
(126000), 318 (sh, 46000), 377 (sh, 11300), 399 (sh, 5000), 411 (4200),
422 (3400), 488 (2900), 573 (sh, 1300), 630 (sh, 540), 687 nm (sh, 160 M-
1cm-1). IR (neat): 3326 (br, OH), 1737 (C=O) cm-1. 1H NMR (400 MHz,
CDCl3): d = 4.52 (t, J = 7 Hz, 4H), 4.42 (2t, J = 7 Hz, 4H), 3.68 (t, J = 7 Hz,
4H), 3.62 (t, J = 7 Hz, 4H), 1.90 (m, 4H), 1.80 (m, 4H), 1.75 (OH, 4H),
1.65–1.47 (m, 16H). 13C NMR (100 MHz, CDCl3) : d = 163.6 (two peaks),
147.2, 147.0, 146.6, 146.5, 146.4 (two peaks), 146.1, 146.0, 145.6, 145.5,
145.3, 144.6, 144.4, 144.2, 143.8, 143.5, 143.4, 143.0, 142.5, 142.2, 142.1,
141.9, 141.6, 140.3, 139.1, 138.4, 71.8, 71.3, 67.3, 67.2, 62.5 (two peaks),
51.8, 32.2, 32.1, 28.4, 28.3, 22.4, 22.3 ppm. MALDI-TOF-MS: m/z =
1268.35 (100%, [M]+, calcd for C86H44O12: 1268.28), 1291.34 (27%,
[M+Na]+, calcd C86H44O12Na: 1291.27).
Compound 26e. Prepared from 18e (0.280 g, 0.28 mmol) and obtained
as a brown glassy product (79 mg, 16%). UV/Vis (CH2Cl2): lmax (ɛ) = 250
(137500), 318 (sh, 43200), 377 (sh, 13700), 399 (sh, 5300), 411 (4300),
423 (3400), 487 (2900), 573 (sh, 1300), 629 (sh, 540), 688 nm (sh, 160 M-
1cm-1). IR (neat): 1751 (C=O), 1732 (C=O) cm-1. 1H NMR (400 MHz,
CDCl3): d = 4.73 (m, 2H), 4.41 (m, 6H), 3.70 (m, 8H), 1.82 (m, 4H), 1.69
(m, 4H), 1.50-1.19 (m, 40H), 0.95 (s, 36H) ppm. 13C NMR (100 MHz,
CDCl3): d = 163.9, 163.8, 147.2, 147.0, 146.8, 146.6, 146.5, 146.3 (two
peaks), 146.1, 145.5, 145.4, 144.6, 144.4, 144.1, 143.8, 143.5, 143.4,
143.0, 142.5, 142.2, 141.9, 141.6, 140.4, 138.6, 138.4, 137.7, 71.8, 71.6,
67.5, 67.2, 63.8, 52.9, 32.9 (two peaks), 29.4 (two peaks), 29.1, 29.0, 28.7,
28.6, 27.9 (two peaks), 26.2, 26.0, 25.9, 25.7, 21.1 (two peaks) ppm.
Compound 30b. Prepared from 27b (82 mg, 53 μmol) and obtained as a
red-brown glassy product (57 mg, 85%). UV/Vis (CH2Cl2): lmax (ɛ) = 248
(123000), 309 (sh, 48200), 356 (sh, 20300), 397 (5000), 409 (sh, 3100),
421 (3000), 481 (3700), 620 nm (sh, 500 M-1cm-1). IR (neat): 3339 (br, OH),
1739 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): d = 4.43 (m, 8H), 3.64 (m,
8H), 1.85 (m, 12H), 1.60 (m, 8H), 1.51 (m, 8H) ppm. 13C NMR (100 MHz,
CDCl3) : d = 163.7, 163.6, 163.5, 147.5, 147.2, 146.4, 146.1 (two peaks),
145.6, 145.3, 145.1, 145.0, 144.7 (two peaks), 144.6, 144.3 (two peaks),
144.2, 144.0, 143.7 (two peaks), 143.4, 143.1, 142.9, 142.8, 142.3, 141.9,
141.6 (two peaks), 138.9, 138.7, 71.7, 71.6, 70.4, 67.3, 67.2, 62.5, 53.7,
53.44, 51.5, 32.2, 32.1, 28.3, 22.3 (two peaks) ppm. MALDI-TOF-MS: m/z
= 1268.47 ([M]+, calcd for C86H44O12: 1268.28).
MALDI-TOF-MS: m/z
=
1719.83 ([M+H]+, calcd for C114H101O12Si2:
1719.19).
Compound 29c. Prepared from 26c (96 mg, 60 μmol) and obtained as a
brown glassy product (71 mg, 89%). UV/Vis (CH2Cl2): lmax (ɛ) = 249
(131000), 319 (sh, 39200), 377 (sh, 11400), 399 (sh, 4800), 411 (4000),
423 (3300), 489 (2800), 575 (sh, 1300), 631 (sh, 520), 689 nm (sh, 160 M-
1cm-1). IR (neat): 3325 (br, OH), 1741 (C=O) cm-1. 1H NMR (400 MHz,
CDCl3): d = 4.51 (t, J = 7 Hz, 4H), 4.40 (t, J = 7 Hz, 4H), 3.66 (t, J = 6 Hz,
4H), 3.62 (t, J = 6 Hz, 4H), 1.91–1.73 (m, 12H), 1.65-1.38 (m, 20H) ppm.
13C NMR (100 MHz, CDCl3): d = 163.6 (two peaks), 147.2, 147.0, 146.6,
146.5 (two peaks), 146.4, 146.2, 146.1, 145.6, 145.5, 145.4, 144.7, 144.4,
144.2, 143.9, 143.6, 143.4, 143.1, 142.6, 142.2, 142.1, 142.0, 141.7, 140.4,
139.2, 138.5, 71.8, 71.3, 67.4, 67.3, 62.8 (two peaks), 51.8, 32.6 (two
peaks), 28.6, 28.5, 25.9, 25.8, 25.5, 25.4 ppm. MALDI-TOF-MS: m/z =
1324.38 ([M]+, calcd for C90H52O12: 1324.35).
Compound 27e. Prepared from 18e (0.280 g, 0.28 mmol) and obtained
as a red-brown glassy product (102 mg, 21%). UV/Vis (CH2Cl2): lmax (ɛ) =
253 (114000), 310 (sh, 43200), 357 (sh, 17000), 397 (4700), 409 (sh,
3000), 422 (2700), 481 (3200), 620 nm (sh, 440 M-1cm-1). IR (neat):
u = 1744 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): d = 4.63-4.23 (m, 8H),
3.79 (m, 4H), 3.69 (t, J = 7 Hz, 4H), 1.75 (m, 8H), 1.48–1.13 (m, 40H), 1.00
(s, 9H), 0.99 (s, 9H), 0.96 (s, 9H), 0.94 (s, 9H) ppm. 13C NMR (100 MHz,
CDCl3): d = 163.9, 163.6, 163.4, 148.5, 147.5, 147.3, 147.2, 146.4 (two
peaks), 146.2, 146.1 (two peaks), 146.0, 145.6, 145.5, 145.3, 145.2 (two
peaks), 145.0, 144.9, 144.8, 144.7 (two peaks), 144.6, 144.5, 144.4, 144.2,
144.1, 144.0 (two peaks), 143.8, 143.7, 143.5, 143.3 (two peaks), 142.9
(two peaks), 142.8, 142.6, 142.3, 142.0, 141.9, 141.6, 141.5, 141.2, 140.8,
138.9 (two peaks), 138.6 (two peaks), 71.9, 71.6, 70.4, 67.4, 67.3, 67.2,
63.9, 63.8, 63.5, 53.8, 51.9, 33.1, 32.9, 32.8, 29.7, 29.4, 29.3 (two peaks),
29.2 (two peaks), 28.9 (two peaks), 28.8, 28.7, 28.4 (two peaks), 27.9,
26.5, 26.3, 26.0, 25.7, 25.6 (two peaks), 25.0 (two peaks), 21.1 (three
Compound 30c. Prepared from 27c (82 mg, 51 μmol) and obtained as a
red-brown glassy product (54 mg, 80%). UV/Vis (CH2Cl2): lmax (ɛ) = 252
(132800), 310 (sh, 50000), 358 (sh, 19400), 397 (sh, 5000), 409 (3000),
421 (2900), 480 (3600), 620 nm (sh, 500 M-1cm-1). IR (neat): 3338 (br, OH),
1741 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): d = 4.42 (m, 8H), 3.64 (m,
8H), 1.81(m, 8H), 1.58 (m, 8H), 1.51–1.38 (m, 12H) ppm. 13C NMR (100
MHz, CDCl3): d = 163.7, 163.6 (two peaks), 147.6, 147.3, 146.5, 146.2,
146.1, 145.6, 145.4, 145.2, 145.1, 144.7(two peaks), 144.6, 144.4 (two
peaks), 144.2, 144.1, 143.8, 143.7, 143.5, 143.2, 143.0, 142.4, 141.9,
141.6 (two peaks), 138.9, 138.7, 71.7, 71.6, 70.4, 67.3, 62.7, 53.7, 51.5,
32.6 (two peaks), 28.5 (two peaks), 28.4, 25.8 (two peaks), 25.7, 25.4 (two
peaks), 25.3 ppm. MALDI-TOF-MS: m/z = 1324.45 (100%, [M]+, calcd for
C90H52O12: 1324.34), 1347.35 (15%, [M+Na]+, calcd. for C90H52O12Na:
1347.34), 1363.26 (20%, [M+K]+, calcd for C90H52O12K: 1363.31).
peaks) ppm. MALDI-TOF-MS: m/z
C114H101O12Si2: 1718.69).
=
1718.00 ([M+H]+, calcd for
General procedure for the desilylation of bis-adducts. BF3.OEt2 (10-
15 eq.) was added to a solution of the appropriate bis-adducts (25a, 26b-
e or 27b-e, 1 eq.) in CH2Cl2/CH3CN (2:1). The resulting mixture was stirred
at rt overnight, then filtered through a plug (SiO2, CH2Cl2/MeOH, 95:5) and
concentrated. Column chromatography (SiO2, CH2Cl2/MeOH) gave the
corresponding bis-adducts 28a, 29b-e or 30b-e.
Compound 28a. Prepared from 25a (77 mg, 52 μmol) and obtained as an
orange-brown glassy product (55 mg, 88%). UV/Vis (CH2Cl2): lmax (ɛ) =
257 (147000), 321 (sh, 45000), 379 (sh, 15100), 438 (4100), 470 (sh,
Compound 29d. Prepared from 26d (70 mg, 42 μmol) and obtained as a
brown glassy product (38 mg, 66%). UV/Vis (CH2Cl2): lmax (ɛ) = 249
(137000), 317 (sh, 43000), 378 (sh, 11300), 399 (sh, 5300), 411 (4400),
421 (3400), 487 (3000), 577 (sh, 1300), 632 (sh, 530), 688 nm (sh, 160 M-
1cm-1). IR (neat): 3336 (br, OH), 1743 (C=O) cm-1. 1H NMR (400 MHz,
CDCl3): d = 4.51 (t, J = 7 Hz, 4H), 4.40 (t, J = 7 Hz, 4H), 3.65 (t, J = 7 Hz,
3500), 623 nm (sh, 450 M-1cm-1). IR (neat): 3340 (br, OH), 1741 (C=O) cm-
1
.
1H NMR (400 MHz, CDCl3): d = 4.40 (m, 8H), 3.68 (m, 8H), 1.96-1.62
(m, 16H) ppm. 13C NMR (100 MHz, CDCl3): d = 163.4, 163.1, 148.4, 147.4
(two peaks), 147.3, 146.2, 145.9 (two peaks), 145.8, 145.7, 145.4, 145.3,
14
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10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
4H), 3.62 (t, J = 7 Hz, 4H), 1.87 (m, 4H), 1.77 (m, 4H), 1.56 (m, 16H), 1.43–
1.34 (m, 20H) ppm. 13C NMR (100 MHz, CDCl3): d = 163.6 (two peaks),
147.2, 146.9, 146.5 (two peaks), 146.4, 146.1, 146.0, 145.6, 145.5, 145.3,
144.6, 144.4, 144.1, 143.8, 143.5 (two peaks), 143.4, 143.0, 142.5, 142.2,
142.1, 141.9, 140.6, 140.3, 139.1, 138.4, 71.8, 71.4, 67.4, 67.3, 62.8 (two
peaks), 51.9, 32.6 (two peaks), 29.0 (two peaks), 28.6, 28.5, 25.9 (two
peaks), 25.8, 25.7 ppm. MALDI-TOF-MS: m/z = 1380.40 ([M]+, calcd for
C94H60O12: 1380.41).
[2]
[3]
For a review on methanofullerenes, see: F. Diederich, L. Isaacs, D. Philp,
Chem. Soc. Rev. 1994, 23, 243-255.
a) A. Hirsch, M. Brettreich, Fullerenes: Chemistry and Reactions, Wiley-
VCH, Weinheim, 2005; b) F. Langa, J.-F. Nierengarten (Eds.),
Fullerenes: principles and applications – 2nd edition; RSC Nanoscience
and Nanotechnology Series, 2011.
[4]
[5]
A. Hirsch, I. Lamparth, H. R. Karfunkel, Angew. Chem. Int. Ed. 1994, 33,
437-438.
a) F. Djojo, A. Herzog, I. Lamparth, F. Hampel, A. Hirsch, Chem. Eur. J.
1996, 2, 1537-1547. b) J. J. Wang, H.-S. Lin, C. Niu, G.-W. Wang, Org.
Biomol. Chem. 2017, 15, 3248-3254.
Compound 30d. Prepared from 27d (95 mg, 57 μmol) and obtained as a
red-brown glassy product (55 mg, 70%). UV/Vis (CH2Cl2): lmax (ɛ) = 252
(142500), 309 (sh, 55100), 357 (sh, 21500), 397 (5300), 409 (sh, 3400),
421 (3100), 481 (3800), 619 nm (sh, 550 M-1cm-1). IR (neat): 3316 (br, OH),
1741 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): d = 4.40 (m, 8H), 3.64 (m,
8H), 1.79 (m, 8H), 1.58 (m, 12H), 1.48–1.34 (m, 24H) ppm. 13C NMR (100
MHz, CDCl3): d = 163.6, 163.5, 147.6, 147.2, 146.4, 146.1, 146.0, 145.5,
145.3, 145.1, 145.0, 144.7 (two peaks), 144.6, 144.4 (two peaks), 144.1,
144.0, 143.7 (two peaks), 143.4, 143.3, 143.1, 142.9, 142.3, 141.9, 141.6,
141.5, 138.7, 138.6, 71.7, 70.5, 67.3, 62.8, 53.7, 51.5, 32.6, 28.9 (two
peaks), 28.5, 25.8 (two peaks), 25.9, 25.8, 25.7 ppm. MALDI-TOF-MS: m/z
= 1380.36 ([M]+, calcd for C94H60O12: 1380.41).
[6]
[7]
L. Isaacs, R. F. Haldimann, F. Diederich, Angew. Chem. Int. Ed. 1994,
33, 2339-2342.
a) L. Isaacs, F. Diederich, R. F. Haldimann, Helv. Chim. Acta 1997, 80,
317-342; b) F. Cardulo, P. Seiler, L. Isaacs, J.-F. Nierengarten, R. F.
Haldimann, F. Diederich, T. Mordasini-Denti, W. Thiel, C. Boudon, J.-P.
Gisselbrecht, M. Gross, Helv. Chim. Acta 1997, 80, 343-371.
J.-F. Nierengarten, V. Gramlich, F. Cardullo, F. Diederich, Angew. Chem.
Int. Ed. 1996, 35, 2101-2103.
[8]
[9]
a) J.-F. Nierengarten, T. Habicher, R. Kessinger, F. Cardullo, F.
Diederich, V. Gramlich, J.-P. Gisselbrecht, C. Boudon, M. Gross, Helv.
Chim. Acta 1997, 80, 2238-2276; b) P. R. Ashton, F. Diederich, M.
Gomez-Lopez, J.-F. Nierengarten, J. A. Preece, F. M. Raymo, J. F.
Stoddart, Angew. Chem. Int. Ed. 1997, 36, 1448-1451; c) J.-P. Bourgeois,
L. Echegoyen, M. Fibbioli, E. Pretsch, F. Diederich, Angew. Chem. Int.
Ed. 1998, 37, 2118-2121; d) E. Dietel, A. Hirsch, E. Eichhorn, A. Rieker,
S. Harkbarth, B. Röder, Chem. Commun. 1998, 1981-1982; e) J.-F.
Nierengarten, D. Felder, J.-F. Nicoud, Tetrahedron Lett. 1998, 39, 2747-
2750; f) J.-P. Bourgeois, F. Diederich, L. Echegoyen, J.-F. Nierengarten
Helv. Chim. Acta 1998, 81, 1835-1844; g) R. Kessinger, C. Thilgen, T.
Mordasini, F. Diederich, Helv. Chim. Acta 2000, 83, 3069-3096; h) J.-P.
Bourgeois, C. R. Woods, F. Cardullo, T. Habicher, J.-F. Nierengarten, R.
Gerhig, F. Diederich, Helv. Chim. Acta 2001, 84, 1207-1226; i) T. M.
Figueira-Duarte, A. Gégout, J. Olivier, F. Cardinalli, J.-F. Nierengarten,
Eur. J. Org. Chem. 2009, 3879-3884; j) T. M. Figueira-Duarte, V.
Lloveras, J. Vidal-Gancedo, B. Delavaux-Nicot, C. Duhayon, J. Veciana,
C. Rovira, J.-F. Nierengarten, Eur. J. Org. Chem. 2009, 5779-5787; k) M.
Riala, M. S. Markoulides, E. E. Moushi, N. Chronakis, Chem. Commun.
2011, 47, 11948-11950.
Compound 29e. Prepared from 26e (60 mg, 35 μmol) and obtained as a
brown glassy product (28 mg, 56%). UV/Vis (CH2Cl2): lmax (ɛ) = 249
(127200), 319 (sh, 39500), 377 (sh, 11000), 399 (sh, 5200), 411 (4300),
422 (3400), 488 (2900), 576 (sh, 1220), 633 (sh, 500), 688 nm (sh, 150 M-
1cm-1). IR (neat): 3330 (br, OH), 1746 (C=O) cm-1. 1H NMR (400 MHz,
CDCl3): d = 4.51 (t, J = 7 Hz, 4H), 4.40 (t, J = 7 Hz, 4H), 3.64 (t, J = 7 Hz,
4H), 3.63 (t, J = 7 Hz, 4H), 1.86 (m, 4H), 1.77 (m, 4H), 1.56 (m, 16H), 1.43–
1.31 (m, 28H) ppm. 13C NMR (100 MHz, CDCl3): d = 163.6 (two peaks),
147.2, 146.9, 146.5, 146.4 (two peaks), 146.2, 146.0, 145.6, 145.5, 145.3,
144.6, 144.4, 144.1, 143.8, 143.5 (two peaks), 143.4, 143.0, 142.5, 142.2,
142.1, 141.9, 141.6, 140.3, 139.1, 138.4, 71.8, 71.4, 67.4, 67.3, 62.9 (two
peaks), 51.9, 32.7 (two peaks), 29.4 (two peaks), 29.2 (two peaks), 28.6,
28.5, 26.0, 25.9, 25.7 (two peaks) ppm. MALDI-TOF-MS: m/z = 1436.46
([M]+, calcd for C98H68O12: 1436.47).
Compound 30e. Prepared from 27e (73 mg, 43 μmol) and obtained as a
red-brown glassy product (50 mg, 82%). UV/Vis (CH2Cl2): lmax (ɛ) = 252
(117000), 309 (sh, 46600), 357 (sh, 17900), 397 (sh, 4500), 409 (sh, 2900),
421 (2700), 478 (3300), 630 nm (sh, 310 M-1cm-1). IR (neat): 3330 (br, OH),
1741 (C=O) cm-1. 1H NMR (400 MHz, CDCl3): d = 4.40 (m, 8H), 3.64 (m,
8H), 1.79 (m, 8H), 1.58 (m, 12H), 1.45–1.34 (m, 32H) ppm. 13C NMR (100
MHz, CDCl3): d = 163.6 (two peaks), 163.5, 147.6, 147.2, 146.4, 146.1,
146.0, 145.5, 145.3, 145.1, 145.0, 144.7, 144.6, 144.5, 144.4, 144.0 (two
peaks), 143.8, 143.7, 143.4, 143.3, 143.2, 142.9, 142.3, 141.8, 141.6,
141.5, 138.6, 71.7, 70.4, 67.3, 62.9, 53.7, 51.5, 32.7, 29.3 (two peaks),
29.2 (two peaks), 29.1, 28.5 (two peaks), 28.4, 25.9 (two peaks), 25.8,
25.7 (two peaks), 25.6 ppm. MALDI-TOF-MS: m/z = 1436.26 ([M]+, calcd
for C98H68O12: 1436.47).
[10] For reviews, see: a) F. Diederich, R. Kessinger, Acc. Chem. Res. 1999,
32, 537-545; b) C. Thilgen, F. Diederich, Chem. Rev. 2006, 106, 5049-
5135; c) C. Thilgen, F. Diederich, C. R. Chimie 2006, 9, 868-880.
[11] U. Reuther, T. Brandmüller, W. Donaubauer, F. Hampel, A. Hirsch,
Chem. Eur. J. 2002, 8, 2262-2273.
[12] a) Z. Zhou, D. I. Schuster, S. R. Wilson, J. Org. Chem. 2003, 68, 7612-
7617; b) N. Chronakis, A. Hirsch, Chem. Commun. 2005, 3709-3711; c)
M. Riala, N. Chronakis, Org. Lett. 2011, 13, 2844-2847; d) D. Sigwalt, M.
Holler, J.-F. Nierengarten, Tetrahedron Lett. 2013, 54, 3160-3163; e) M.
Riala, N. Chronakis, Chem. Commun. 2014, 50, 1995-1998.
[13] For reviews, see: a) A. Hirsch, Chem. Rec. 2005, 5, 196-208; b) N.
Chronakis, A. Hirsch, C. R. Chimie 2006, 9, 862-867.
[14] S. Guerra, T. M. N. Trinh, F. Schillinger, L. Muhlberger, D. Sigwalt, M.
Holler, J.-F. Nierengarten, Tetrahedron Lett. 2013, 54, 6251-6257.
[15] For threefold Bingel reactions using tert-butyl(trialkoxy)silane derivatives
bearing three malonate substituents, see: a) S. Guerra, F. Schillinger, D.
Sigwalt, M. Holler, J.-F. Nierengarten, Chem. Commun. 2013, 49, 4752-
4754; b) D. Sigwalt, F. Schillinger, S. Guerra, M. Holler, M. Berville, J.-F.
Nierengarten, Tetrahedron Lett. 2013, 54, 4241-4244.
Acknowledgements
This research was supported by the International Center for
Frontier Research in Chemistry and the LabEx “Chimie des
Systèmes Complexes”. S.G. gratefully thanks the Swiss National
Foundation and T.M.N.T. the University of Strasbourg (Idex) for
their post-doctoral fellowships. We further thank J.-M. Strub for
the mass spectra.
[16] A. Bouzide, G. Sauvé, Tetrahedron Lett. 1997, 38, 5945-5948.
[17] a) J.-F. Nierengarten, D. Felder, J.-F. Nicoud, Tetrahedron Lett. 2000, 41,
41-44; b) D. Felder, H. Nierengarten, J.-P. Gisselbrecht, C. Boudon, E.
Leize, J.-F. Nicoud, M. Gross, A. Van Dorsselaer, J.-F. Nierengarten,
New J. Chem. 2000, 24, 687-695.
Keywords: Bingel reaction • Fullerene • Macrocycle •
Regiochemistry • Silyl protecting groups
[1]
C. Bingel, Chem. Ber. 1993, 126, 1957-1959.
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10.1002/ejoc.202100571
European Journal of Organic Chemistry
FULL PAPER
Entry for the Table of Contents
Si
O
O
(CH2)n
(CH2)n
O
O
O
O
O
O
O
O
(CH2)n
(CH2)n
O
O
Si
A series of macrocyclic bis-malonates incorporating cleavable di-tert-butylsilylene subunits have been prepared and used for the
regioselective bis-functionalization of [60]fullerene by double Bingel cyclopropanations. Upon functionalization of the fullerene sphere,
the bridging di-tert-butylsilylene groups have been cleaved to afford the corresponding acyclic fullerene bis-adducts bearing four alcohol
functions.
Institute and/or researcher Twitter usernames: @INC_CNRS - @Unistra - @LIMA_UMR7042 (Institutions) / @nierengarten6 -
@IwonaNieren (Researchers).
16
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