Synthesis of calix[4]arenylvinylene and calix[4]arenylphenylene oligomers by Stille and Suzuki cross-coupling reactions

Full text of DOI:10.1021/jo980868w

J . Org. Chem. 1998, 63, 9535-9539
9535
similar to that occurring in poly(phenylenevinylene)
(PPV) and poly(paraphenylene) (PPP) polymers, two
classes of extensively conjugated systems that are receiv-
ing considerable attention as promising materials for the
construction of electronic and optoelectronic devices, such
as light-emitting diodes (LED).8
Syn th esis of Ca lix[4]a r en ylvin ylen e a n d
Ca lix[4]a r en ylp h en ylen e Oligom er s by
Stille a n d Su zu k i Cr oss-Cou p lin g Rea ction s
Alessandro Dondoni,*,† Chiara Ghiglione,†
Alberto Marra,† and Marco Scoponi‡
Syntheses of PPV and PPP polymers and analogues
have been reported by various carbon-carbon bond-
forming reactions including the palladium-catalyzed
cross-coupling of aryl halides with bis-stannylethylenes
(Stille reaction),9,10 aryl bis-boronic acids (Suzuki reac-
tion),11,12 and divinylbenzenes (Heck reaction).13,14 For
the application of these reactions in our polymerization
studies, the 1,3-dihalocalix[4]arene derivatives 2 (R ) Br)
and 3 (R ) I) were prepared by regioselective halogena-
tion of the known15 calix[4]arene dipropyl ether 1. The
bromination of 1 proceeded readily under the same
conditions described for the dimethyl ether analog16 to
give the 1,3-dibromo upper-rim substituted calix[4]arene
2 in very high yield. On the other hand, a lower yield of
pure diiodo derivative 3 was obtained by the use of
benzyltrimethylammonium dichloroiodate17 (BTMAICl2)
as iodinating agent.18 Both compounds 2 and 3 were
characterized as being in the cone conformation at room
temperature by the presence of two doublets (J ≈ 13 Hz)
Dipartimento di Chimica, Laboratorio di Chimica Organica,
Universita` di Ferrara, Via Borsari 46, 44100 Ferrara, Italy,
and Centro di Studio su Fotoreattivita` e Catalisi del C.N.R.,
Via Borsari 46, 44100 Ferrara, Italy
Received May 7, 1998
Recent work in our laboratory has focused on the
synthesis of bisphenol A copolyethers and copolyesters
containing lower-rim bound calix[4]arenes on the main
chain.1 The successful polymerization of upper-rim de-
rivatized calix[4]arenes with terephthaloyl chloride was
reported by Blanda and Adou to give two new calixarene-
based polyesters.2 The polymers described by us and
Blanda represent the first examples of incorporation of
calixarene monomers in polymer backbones because the
earlier products were carrying calixarene units as ap-
pendages of the main chains.3 The increasing interest
in calixarene-based polymers arises from the potential
to develop new materials suitable for the construction of
chemical and biochemical sensor devices4 and membranes
for the selective transport of ions.5 Moreover, other
applications may include antioxidants and light stabilizer
additives for polymer commodities.6 It appears that
calixarene insertion in a macromolecular system such as
a polymer chain may enhance the intrinsic properties of
the macrocycle. For instance, the calixarene-bisphenol
A copolyether1 exhibited a 10-fold higher binding affinity
for silver ions relative to calix[4]arene tetrapropyl ether.1b
Given the well-known receptor properties of substituted
calixarenes toward various cations and some anions,7 the
effects calixarene incorporation into polymer chains may
have on such properties now become of interest.
1
in their H NMR spectra for the bridging methylenes at
δ ∼3.3 and 4.2.19
(8) Skotheim, T. A. Handbook of Conducting Polymers; M. Dekker:
New York, 1986; Vol. 1. See also: Strukelj, M.; Miller, T. M.;
Papadimitrakopoulos, F.; Son, S. J . Am. Chem. Soc. 1995, 117, 11976
and references therein.
(9) For reviews of the Stille reaction, see: (a) Stille, J . K. Angew.
Chem., Int. Ed. Engl. 1986, 25, 508. (b) Mitchell, T. N. Synthesis 1992,
803. (c) Farina, V.; Krishnamurthy, V.; Scott, W. J . Org. React. 1997,
50, 1.
(10) For the synthesis of polymers by the Stille reaction, see: (a)
Galarini, R.; Musco, A.; Pontellini, R.; Bolognesi, A.; Destri, S.;
Catellani, M.; Mascherpa, M.; Zhuo, G. J . Chem. Soc., Chem. Commun.
1991, 364. (b) Bolognesi, A.; Catellani, M.; Porzio, W.; Speroni, F.;
Galarini, R.; Musco, A.; Pontellini, R. Polymer 1993, 34, 4150. (c) Bao,
Z.; Chan, W. K.; Yu, L. J . Am. Chem. Soc. 1995, 117, 12426. (d)
Babudri, F.; Cicco, S. R.; Farinola, G. R.; Naso, F.; Bolognesi, A.; Porzio,
W. Macromol. Rapid Commun. 1996, 17, 905.
(11) For a recent review of the Suzuki reaction, see: (a) Miyaura,
N.; Suzuki, A. Chem. Rev. 1995, 95, 2457.
(12) For the synthesis of polymers by the Suzuki reaction, see: (a)
Kovacic, P.; J ones, B. M. Chem. Rev. 1987, 87, 357. (b) Rehahn, M.;
Schlu¨ter, A.-D.; Wegner, G.; Feast, W. J . Polymer 1989, 30, 1060. (c)
Frahn, J .; Karakaya, B.; Scha¨fer, A.; Schlu¨ter A.-D. Tetrahedron 1997,
53, 15459.
We have explored synthetic approaches to other calix-
arene-based polymers and report here the synthesis of
oligomers in which 1,3-(distal)calix[4]arenes are linked
to 1,2-vinylene and p-phenylene units by a single carbon-
carbon bond merging from the upper rim of the macro-
cycle. The main structural unit in these products is
(13) For a recent review of the Heck reaction, see: (a) de Meijere,
A.; Meyer, F. E. Angew. Chem., Int. Ed. Engl. 1994, 33, 2379.
(14) For the synthesis of polymers by the Heck reaction, see: (a)
Heitz, W.; Bru¨gging, W.; Freund, L.; Gailberger, M.; Greiner, A.; Lung,
H.; Kampschulte, U.; Niessner, N.; Osan, F.; Schmidt, H.-W.; Wicker,
M. Makromol. Chem. 1988, 189, 119. (b) Weitzel, H.-P.; Mu¨llen, K.
Makromol. Chem. 1990, 191, 2837. (c) Martelock, H.; Greiner, A.; Heitz,
W. Makromol. Chem. 1991, 192, 967. (d) Bao, Z.; Chen, Y.; Cai, R.;
Yu, L. Macromolecules 1993, 26, 5281.
(1) (a) Dondoni, A.; Ghiglione, C.; Marra, A.; Scoponi, M. Chem.
Commun. 1997, 673. (b) Dondoni, A.; Ghiglione, C.; Marra, A.; Scoponi,
M. Macromol. Chem. Phys., in press.
(2) Blanda, M. T.; Adou, E. Chem. Commun. 1998, 139. Blanda, M.
T.; Adou, E. Polymer 1998, 39, 3821.
(3) (a) Shinkai, S.; Kawaguchi, H.; Manabe, O. J . Polym. Sci., Polym.
Lett. 1988, 26, 391. (b) Harris, S. J .; Barrett, G.; McKervey, M. A. J .
Chem. Soc., Chem. Commun. 1991, 1224. (c) Glennon, J . D.; O’Connor,
K.; Srijarani, S.; Manley, K.; Harris, S. J .; McKervey, M. A. Anal. Lett.
1993, 26, 153.
(15) Arduini, A.; Fabbi, M.; Mantovani, M.; Mirone, L.; Pochini, A.;
Secchi, A.; Ungaro, R. J . Org. Chem. 1995, 60, 1454.
(4) (a) Arrigan, D. W. M.; Svehla, G.; Harris, S. J .; McKervey, M. A.
Electroanalysis 1995, 6, 97. (b) Diamond, D.; McKervey, M. A. Chem.
Soc. Rev. 1996, 15.
(5) Nijenhuis, W. F.; Buitenhuis, E. G.; De J ong, F.; Sudho¨lter, E.
J . R.; Reinhoudt, D. N. J . Am. Chem. Soc. 1991, 113, 7963.
(6) (a) Pastor, S. D.; Odorisio, P. USP 4617336/1986; Chem. Abstr.
1987, 106, 6038X. (b) Seiffarth, K.; Schulz, M.; Go¨rmar, G.; Bachmann,
J . Polym. Deg. Stab. 1989, 24, 73.
(16) van Loon, J .-D.; Arduini, A.; Coppi, L.; Verboom, W.; Pochini,
A.; Ungaro, U.; Harkema, S.; Reinhoudt, D. N. J . Org. Chem. 1990,
55, 5639.
(17) Kajigaeshi, S.; Kakinami, T.; Yamasaki, H.; Fujisaki, S.; Kondo,
M.; Okamoto, T. Chem. Lett. 1987, 2109.
(18) The use of Hg(CF3CO2)2/I2 gave 3 contaminated by mercury
salts, while PhI(CF3CO2)2/I2 gave
derivatives.
a mixture of mono and diiodo
(7) (a) Ikeda, A.; Shinkai, S. Chem. Rev. 1997, 97, 1713. (b) Ikeda,
A.; Tsudera, T.; Shinkai, S. J . Org. Chem. 1997, 62, 3568. (c) Lhota´k,
P.; Shinkai, S. J . Phys. Org. Chem. 1997, 10, 273. (d) Ma, J . C.;
Dougherty, D. A. Chem. Rev. 1997, 97, 1303.
(19) These NMR features are currently taken as an evidence of the
cone conformation of calix[4]arene derivatives. See: Gutsche, C. D.
Calixarenes, The Royal Society of Chemistry: Cambridge, 1992; pp
67-86.
10.1021/jo980868w CCC: $15.00 © 1998 American Chemical Society
Published on Web 11/24/1998

9536 J . Org. Chem., Vol. 63, No. 25, 1998
Notes
Sch em e 1
Both calixarene monomers 2 and 3 were first reacted20
with (E)-1,2-bis(tributylstannyl)ethylene (4) under the
conditions of the Stille cross-coupling reaction10d [Pd
(OAc)2 with 4-fold PPh3, toluene, 100 °C)] (Scheme 1).
Both monomers were used in equimolar amounts, while
the palladium salt was 4 mol %. After the complete
consumption of the reagents (5 days, TLC analysis), the
product 6 was isolated by evaporation of the solvent and
purified by trituration with boiling n-hexane. Compa-
rable yields of isolated 6 were obtained starting from
either the dibromo monomer 2 (52%) or the diiodo
derivative 3 (64%). The use of equimolar amounts of
palladium salt,21 higher reaction temperature (140 °C in
cumene), and longer reaction time (14 days) gave similar
results. It was established by GPC analysis (THF, 45
°C, refractive index detection) that the product 6 is a
mixture of calix[4]arenylvinylene oligomers with an
average molecular weight (Mw) ranging between 1740
and 1030 and a polydispersity (Mw/Mn) between 1.3 and
1.2 depending on whether the starting calixarene mono-
mer was 2 or 3. However, the GPC analysis under
different conditions (CHCl3, 35 °C, UV detection) gave
for the oligomer 6 prepared from 2 a Mw value of 2040.
The calibration of the molecular weights was obtained
by comparison of the MALDI-TOF mass spectrum of 6
with its GPC chromatograms. The mass spectrum of 6
showed the presence of a main product with molecular
weight ranging from 2268 to 2370, corresponding to a
tetramer with different chain ends. Thus, we estimated
calibration factors of ca. 1.3 and 1.1 relative to the
molecular weights determined by GPC analysis in THF
and CHCl3, respectively. We assumed that these calibra-
tion factors were also valid for the overall GPC data
obtained from the other oligomers.
Sch em e 2
yield (16%),22 by the Stille cross-coupling reaction of 4
with the upper-rim monobromocalix[4]arene tripropyl
ether 9 (Scheme 2). The C2-symmetrical compound 10
Although the 1H NMR spectrum of 6 was rather
complex due to the presence of the various oligomers, the
cone conformation of the calixarene moieties was safely
established from the presence of signals for the bridging
methylenes similar to those of the monomers 2 and 3.
On the other hand, the trans olefinic linkage was
assigned in analogy with the results of the 2-fold Stille
cross-coupling polymerization of the bis-stannylethylene
4 with diiodoarenes.10d These assignments were con-
firmed by considering the structure of the 1,2-bis(calix-
[4]arene) ethylene 10 that was obtained, although in low
1
showed a well resolved first-order H NMR spectrum with
a single set of signals for both the calixarene and vinyl
protons. Similar to trans-stilbene, a sharp signal corre-
sponding to the vinyl protons appeared at 7.04 ppm.
Moreover, the cone conformation was substantiated by
the characteristic chemical shift (δ ) 3.22, 3.35 and 4.40,
4.46) and coupling constant values (J ≈ 13 Hz) of the
two types of diastereotopic proton signals of the meth-
ylene bridges.
Then we considered the synthesis of polymers having
the calixarene units linked through a phenylene moiety
by the Suzuki cross-coupling reaction.13b,c Unlike the
Stille reaction, the palladium-catalyzed coupling of aryl-
(20) The palladium-catalyzed cross-coupling reactions of unprotected
halogenophenols have been reported in several instances. For recent
examples, see: (a) Gothelf, K. V.; Torssell, K. B. G. Acta Chem. Scand.
1994, 48, 61. (b) Gothelf, K. V.; Torssell, K. B. G. Acta Chem. Scand.
1994, 48, 165. (c) Roshchin, A. I.; Bumagin, N. A.; Beletskaya, I. P.
Tetrahedron Lett. 1995, 36, 125. (d) Rai, R.; Aubrecht, K. B.; Collum,
D. B. Tetrahedron Lett. 1995, 36, 3111.
(21) The efficiency of the palladium complex generated from Pd
(OAc)2 and PPh3 was proved by duplication of the results reported by
Naso et al. (see the relevant reference in ref 10d).
(22) Pure compound 10 was isolated by chromatography from a
complex mixture of side products arising from the 1-fold cross-coupling
reaction and the decomposition of 9. The use of benzene as a solvent
gave similar results, while at lower temperature (50 °C) the formation
of 10 did not occur.

Notes
J . Org. Chem., Vol. 63, No. 25, 1998 9537
boronic acids with bromocalixarene derivatives has been
recently reported.23 Thus, the reaction of the 1,3-
dibromocalix[4]arene derivative 2 with 1,4-phenylenebis-
(boronic acid) 5 was carried out under the agency of
Pd(PPh3)4 as a catalyst (Scheme 1). The monomers 2 and
5 and the palladium catalyst were used in equimolar
amounts. The reaction afforded the product 7 (61%
yield), which constituted a mixture of calix[4]arenyl-
phenylene oligomers. The product 7 was purified by
trituration with boiling diethyl ether and characterized
by GPC (CHCl3, 35 °C, UV detection). Since this analysis
gave Mw ) 1580 and Mw/Mn ) 1.3, the most abundant
fraction is constituted of trimers. The 1H NMR spectrum
showed the same signals for the methylene bridges as
described above for 6 and 9. Therefore, it was concluded
that the calix[4]arene moieties in this material are also
in the cone conformation.
this may be ascribed both to the modest length and high
rigidity of the calix[4]arenylvinylene and phenylene
oligomeric chains.
Exp er im en ta l Section
All moisture-sensitive reactions were performed under a
nitrogen atmosphere using oven-dried glassware. All solvents
were dried over standard drying agents27 and freshly distilled
prior to use. Flash column chromatography28 was performed
on silica gel 60 (230-400 mesh). Reactions were monitored by
TLC on silica gel 60 F254 with detection by charring with sulfuric
acid. Melting points were determined with a Mettler DSC 820
differential scanning calorimeter. 1H (300 MHz) and 13C (75
MHz) NMR were recorded at rt for CDCl3 solutions, unless
otherwise specified. Assignments were aided by homo- and
heteronuclear two-dimensional experiments. MALDI-TOF mass
spectra were acquired using 2,6-dihydroxybenzoic acid or 3,5-
dimethoxy-4-hydroxycinnamic acid as the matrix. The molecular
weights of the polymers were determined by gel permeation
chromatography (GPC) both in CHCl3 at 35 °C and in THF at
45 °C (flow rate ) 0.8 mL/min, sample concentration ranging
from 0.1 to 0.5% w/v) using a chromatograph equipped with
Waters pump model 515, Waters UV detector model 484, Waters
RI detector model 410, and two gel mixed C (5 µm) microcolumns
(purchased from Polymer Laboratories). A Pentium personal
computer equipped with Millennium 32 software was used for
data acquisition and elaboration and microcolumn calibration.
The calibration was carried out using at least 10 narrow
polydispersity polystyrene standards ranging from 5.8 × 102 to
2.0 × 106 for the different experimental conditions. Since the
elemental analyses of calixarenes are very often uncorrected29
(found carbon values considerably lower than the calculated
ones), the identity and purity of the nonoligomeric new com-
pounds were established by MS and NMR analyses. Tetrakis-
As a second approach, we considered the Heck reac-
tion15 of the calixarene 2 with p-divinylbenzene in the
presence of palladium catalyst and a base. No product
from this cross-coupling reaction was obtained despite
several attempts under different conditions.24 Therefore,
the calixarene 12 was designed as monomer for the 2-fold
Heck reaction with a p-dihalobenzene. It was hoped that
some reactivity would appear because the vinyl group
was not directly linked to the upper rim of the macro-
cycle. Compound 12 was prepared in quite good yield
by the Suzuki-type cross-coupling of 2 with the arylbo-
1
ronic acid 11 and adequately characterized by H NMR
spectroscopy. Unfortunately, the attempted Heck reac-
tion of 11 with p-diiodobenzene likewise did not produce
any extended coupling product.
(triphenylphosphine)palladium30 and bis-stannylethylene31
4
were prepared as described. Known16 calixarene 1 was prepared
as reported for the synthesis of the upper rim tetra-tert-butylated
analogue.32
5,17-Dibr om o-25,27-d ih yd r oxy-26,28-d ip r op oxyca lix[4]-
a r en e (2). To a cooled (0 °C), stirred solution of 1 (1.00 g, 1.97
mmol) in anhydrous CHCl3 (40 mL) was added a solution of Br2
(0.20 mL, 3.94 mmol) in anhydrous CHCl3 (40 mL) during 20
min. The solution was stirred at 0 °C for 1 h and at rt for 1 h
and then concentrated to give 2 (1.30 g, 99%) as a white solid:
mp 372 °C (from CHCl3); 1H NMR δ 1.24 (t, 6 H, J ) 7.0 Hz,
CH3CH2CH2), 2.01-2.12 (m, 4 H, CH3CH2CH2), 3.34 and 4.23
(2 d, 8 H, J ) 13.9 Hz, ArCH2Ar), 3.98 (t, 4 H, J ) 7.0 Hz, CH3-
CH2CH2), 6.81 (t, 2 H, J ) 6.9 Hz, Ar), 6.93 (d, 4 H, J ) 6.9 Hz,
Ar), 7.18 (s, 4 H, Ar), 8.38 (s, 2 H, OH); 13C NMR δ 10.8 (CH3-
CH2CH2), 23.5 (CH3CH2CH2), 31.2 (ArCH2Ar), 78.4 (CH3-
CH2CH2,) 125.5, 129.3, 130.0, 130.7, 132.7, 151.9 (Ar); MALDI-
TOF MS for C34H34Br2O4 (666.46) m/z ) 689.4 [M+ + Na], 705.5
[M+ + K].
25,27-Dih yd r oxy-5,17-d iiod o-26,28-d ip r op oxyca lix[4]-
a r en e (3). A mixture of 1 (250 mg, 0.49 mmol), benzyltri-
methylammonium dichloroiodate (383 mg, 1.10 mmol), sodium
hydrogencarbonate (200 mg, 2.38 mmol), anhydrous CH2Cl2 (5
mL), and anhydrous CH3OH (2 mL) was stirred at rt for 7 h
and then diluted with CH2Cl2 (20 mL) and filtered. The solution
was washed with 10% aqueous NaHCO3 (10 mL), water (10 mL),
10% aqueous Na2S2O3 (10 mL), and water (10 mL), dried
(Na2SO4), and concentrated. The residue was triturated at rt
The receptor properties toward silver ions of the
oligomer 6, 1,2-bis(calix[4]arene) ethylene 10, and calix-
[4]arene O-tetrapropyl ether were investigated by 1H
NMR titration experiments as described by Shinkai and
co-workers.25 The relevant association constant values
(Kassoc) obtained from nonlinear least-squares computa-
tion26 of the titration curves were the same for the three
compounds (ca. 100 M-1). This value is lower than that
reported by Shinkai for calix[4]arene O-tetrapropyl ether.25
Thus, enhancement of binding properties arising from
the calixarene insertion in polymeric chains is not
realized in these oligomers as anticipated. Very likely,
(27) Perrin, D. D.; Armarego, W. L. F. Purification of Laboratory
Chemicals, 3rd ed.; Pergamon Press: Oxford, 1988.
(28) Still, W. C.; Kahn, M.; Mitra, A. J . Org. Chem. 1978, 43, 2923.
(29) (a) Bo¨hmer, V.; J ung, K.; Scho¨n, M.; Wolff, A. J . Org. Chem.
1992, 57, 790. (b) Gutsche, C. D.; See, K. A. J . Org. Chem. 1992, 57,
4527. (c) Marra, A.; Dondoni, A.; Sansone, F. J . Org. Chem. 1996, 61,
5155. (d) Dondoni, A.; Marra, A.; Scherrmann, M.-C.; Casnati, A.;
Sansone, F.; Ungaro, R. Chem. Eur J . 1997, 3, 1774.
(30) Coulson, D. R. Inorg. Synth. 1972, 13, 121.
(31) Renaldo, A. F.; Labadie, J . W.; Stille, J . K. Org. Synth. 1989,
67, 86.
(32) Iwamoto, K.; Araki, K.; Shinkai, S. J . Org. Chem. 1991, 56,
4955.
(23) (a) J uneja, R. K.; Robinson, K. D.; J ohnson, C. P.; Atwood, J .
L. J . Am. Chem. Soc. 1993, 115, 3818. (b) Wong, M. S.; Nicoud, J .-F.
Tetrahedron Lett. 1993, 34, 8237. (c) Haino, T.; Harano, T.; Matsumura,
K.; Fukazawa, Y. Tetrahedron Lett. 1995, 36, 5793.
(24) Pd catalyst (from 4 to 100 mol %): Pd(PPh3)4, Pd(OAc)2/PPh3,
Pd(OAc)2/dppe, Pd(OAc)2/P(o-tol)3. Solvent: DMF, pyridine, toluene.
Base: NEt3, NEt(i-Pr)2, pyridine. Temperature and time: 80-110 °C,
from 3 days to 2 weeks.
(25) Ikeda, A.; Tsuzuki, H.; Shinkai, S. J . Chem. Soc., Perkin Trans.
2 1994, 2073.
(26) Macomber, R. S. J . Chem. Educ. 1992, 69, 375.

9538 J . Org. Chem., Vol. 63, No. 25, 1998
Notes
with CH2Cl2 (2 mL) and then 2-butanone (2 mL) to give 3 (150
mg, 40%) as a yellow solid. An analytical sample was obtained
by column chromatography on silica gel (3:2 cyclohexane-CH2-
ArCH2Ar), 3.78 (t, 4 H, J ) 7.0 Hz, CH3CH2CH2), 3.82 (t, 2 H,
J ) 7.0 Hz, CH3CH2CH2), 4.72 (s, 1 H, OH), 6.40 (m, 6 H, Ar),
6.78 (t, 1 H, J ) 7.0 Hz, Ar), 6.98 (t, 1 H, J ) 7.0 Hz, Ar), 7.11
(d, 2 H, J ) 7.0 Hz, Ar), 7.19 (d, 2 H, J ) 7.0 Hz, Ar); 13C NMR
δ 9.6 and 10.8 (CH3CH2CH2), 22.3 and 23.4 (CH3CH2CH2), 30.7
(ArCH2Ar), 71.0 and 77.4 (CH3CH2CH2), 119.3, 122.9, 127.7,
127.8, 128.4, 129.2, 131.2, 132.6, 133.4, 137.2, 153.3, 154.4, 156.8
(Ar). MALDI-TOF MS for C37H42O4 (550.74) m/z ) 573.6 [M+
+ Na], 589.9 [M+ + K].
1
Cl2): mp 360 °C; H NMR δ 1.30 (t, 6 H, J ) 6.9 Hz, CH3CH2-
CH2), 2.02-2.10 (m, 4 H, CH3CH2CH2), 3.32 and 4.24 (2 d, 8 H,
J ) 13.4 Hz, ArCH2Ar), 3.97 (t, 4 H, J ) 6.9 Hz, CH3CH2CH2),
6.82 (t, 2 H, J ) 7.0 Hz, Ar), 6.93 (d, 4 H, J ) 7.0 Hz, Ar), 7.37
(s, 4 H, Ar), 8.43 (s, 2 H, OH); 13C NMR δ 10.9 (CH3CH2CH2),
23.5 (CH3CH2CH2), 31.0 (ArCH2Ar), 78.5 (CH3CH2CH2), 125.5,
129.3, 130.7, 132.7, 136.7 (Ar); MALDI-TOF MS for C34H34I2O4
(760.45) m/z ) 783.7 [M+ + Na], 799.6 [M+ + K].
1,4-P h en ylen ebis(bor on ic a cid ) (5). To a stirred solution
of butyllithium (2.1 mL of a ca. 2.5 M solution in hexane, ca.
5.8 mmol) in anhydrous Et2O (5 mL) was added dropwise a
solution of 1,4-dibromobenzene (0.50 g, 2.12 mmol) in anhydrous
Et2O (5 mL). The suspension was stirred at rt for 2.5 h and
then cooled at -70 °C and treated with trimethyl borate (2.19
g, 21.11 mmol). The mixture was stirred at rt for 5 h and then
diluted with Et2O (20 mL), washed with 1 M HCl (10 mL) and
water (10 mL), dried (Na2SO4), and concentrated to give 5 (0.22
g, 63%) as a white solid: mp >300 °C (from Et2O); 1H NMR (D2O
+ NaOH) δ 7.25 (s, 4 H, Ar). The NMR spectra in CDCl3 and
the elemental analysis indicated that 5 was a mixture of
anhydride and acid derivatives. These findings have already
been reported for other arylboronic acids.12b
The compound 5 was heated at 100 °C for 2 h in neat 1,2-
ethanediol (10 equiv) and then concentrated. The solid residue
was triturated with Et2O and then sublimated (150 °C, 0.05
mbar) to give pure bisethylene 1,4-phenylenebisboronate: mp
225-227 °C (in closed vial); 1H NMR δ 4.40 (s, 8 H, 4 CH2), 7.83
(s, 4 H, Ph); 13C NMR δ 66.1 (4 CH2), 130.5 (2 CB), 134.0 (4
CH). Anal. Calcd for C10H12B2O4: C, 55.14; H, 5.55. Found:
C, 55.29; H, 5.60.
Oligom er 6. A mixture of calixarene 2 (300 mg, 0.45 mmol),
triphenylphosphine (42 mg, 0.16 mmol), palladium(II) acetate
(6 mg, 0.03 mmol), (E)-1,2-bis(tributylstannyl)ethylene (4, 272
mg, 0.45 mmol), and anhydrous toluene (25 mL) was stirred at
100 °C for 5 days in a nitrogen atmosphere and then cooled to
rt, diluted with CH2Cl2 (20 mL), washed with water (3 × 20 mL),
dried (Na2SO4), and concentrated. The residue was triturated
with boiling n-hexane (3 × 5 mL) to give 6 (156 mg, 52 wt %) as
a brown solid: 1H NMR δ 1.22-1.42 (m, 6 H, CH3CH2CH2),
1.98-2.18 (m, 4 H, CH3CH2CH2), 3.28-3.43 and 4.23-4.38 (m,
8 H, ArCH2Ar), 3.88-4.02 (m, 4 H, CH3CH2CH2), 6.62-7.72 (m,
12 H, Ar and CHdCH), 8.21-8.42 (m, 2 H, OH);13C NMR δ 10.8
(CH3CH2CH2), 23.5 (CH3CH2CH2), 31.1-31.6 (ArCH2Ar), 78.4-
78.6 (CH3CH2CH2), 125.2-133.4 (Ar and CHdCH), 151.8-151.9
(Ar). Similar results were obtained using 3 instead of 2 as
starting material.
5-Br om o-26,27,28-tr ipr opoxy-calix[4]ar en e (9). To a cooled
(0 °C), stirred solution of 8 (268 mg, 0.49 mmol) in anhydrous
CHCl3 (5 mL) was added a solution of Br2 (25 µL, 0.49 mmol) in
anhydrous CHCl3 (5 mL) during 20 min. The solution was
stirred at 0 °C for 1 h and at rt for 1 h and then concentrated to
give 9 (303 mg, 99%) as a white solid: mp 132-133 °C (from
1
CHCl3); H NMR δ 0.93 (t, 3 H, J ) 6.4 Hz, CH3CH2CH2), 1.12
(t, 6 H, J ) 6.4 Hz, CH3CH2CH2), 1.82-1.92 (m, 4 H, CH3CH2-
CH2), 2.20-2.30 (m, 2 H, CH3CH2CH2), 3.21 and 4.40 (2 d, 8 H,
J ) 12.5 Hz, ArCH2Ar), 3.24 and 4.34 (2 d, 8 H, J ) 12.5 Hz,
ArCH2Ar), 3.72 (t, 4 H, J ) 6.3 Hz, CH3CH2CH2), 3.82 (t, 2 H,
J ) 6.3 Hz, CH3CH2CH2), 4.78 (s, 1 H, OH), 6.35-6.44 (m, 6 H,
Ar), 6.98 (t, 1 H, J ) 7.0 Hz, Ar), 7.18 (d, 2 H, J ) 7.0 Hz, Ar),
7.23 (s, 2 H, Ar); 13C NMR δ 8.6 and 9.8 (CH3CH2CH2), 21.3
and 22.4 (CH3CH2CH2), 29.6 and 29.7 (ArCH2Ar), 75.6 (CH3-
CH2CH2), 122.2, 126.8, 127.3, 128.2, 129.8, 130.7, 132.2, 132.6,
136.1, 153.4 (Ar); MALDI-TOF MS for C37H41BrO4 (629.64) m/z
) 652.5 [M+ + Na], 668.8 [M+ + K].
Bis(25-h yd r oxy-26,27,28-t r ip r op oxyca lix[4]a r en -5-yl)-
eth ylen e (10). A mixture of calixarene 9 (50 mg, 0.08 mmol),
triphenylphosphine (8 mg, 0.03 mmol), palladium(II) acetate
(∼0.1 mg, ∼0.3 µmol), (E)-1,2-bis(tributylstannyl)ethylene (4, 48
mg, 0.08 mmol), and anhydrous toluene (5 mL) was stirred at
100 °C for 18 h in a nitrogen atmosphere, cooled to rt, diluted
with CH2Cl2 (20 mL), washed with water (3 × 20 mL), dried
(Na2SO4), and concentrated. The residue was eluted from a
column of silica gel with 3:2 cyclohexane-CH2Cl2 (containing
0.3% of Et3N) to give 10 (14 mg, 16%) slightly contaminated by
uncharacterized byproducts. An analytical sample was obtained
by trituration with n-pentane (1 mL) and then CH3OH (1 mL):
1
mp 227-228 °C; H NMR δ 0.92 (t, 6 H, J ) 9.0 Hz, CH3CH2-
CH2), 1.15 (t, 12 H, J ) 9.0 Hz, CH3CH2CH2), 1.82-1.98 (m, 8
H, CH3CH2CH2), 2.22-2.38 (m, 4 H, CH3CH2CH2), 3.22 and 4.46
(2 d, 8 H, J ) 13.5 Hz, ArCH2Ar), 3.35 and 4.40 (2 d, 8 H, J )
13.2 Hz, ArCH2Ar), 3.70-3.88 (m, 8 H, CH3CH2CH2), 3.86 (t, 4
H, J ) 9.0 Hz, CH3CH2CH2), 4.82 (s, 1 H, OH), 6.32-6.49 (m,
12 H, Ar), 6.98 (t, 2 H, J ) 7.7 Hz, Ar), 7.04 (s, 2 H, CHdCH),
7.18 (d, 4 H, J ) 7.7 Hz, Ar), 7.30 (s, 4 H, Ar); 13C NMR (C6D6)
δ 9.9 and 10.9 (CH3CH2CH2), 22.8 and 23.7 (CH3CH2CH2), 31.3
and 31.5 (ArCH2Ar), 76.8 and 77.6 (CH3CH2CH2), 123.5, 123.7,
126.9, 128.0, 128.3, 129.1, 129.3, 129.6, 130.2, 131.6, 132.9, 133.9,
137.6, 153.8, 154.9, 157.5 (Ar). MALDI-TOF MS for C76H84O8
(1125.51) m/z ) 1126.0 [M+ + H], 1148.6 [M+ + Na], 1166.2 [M+
+ K].
Oligom er 7. A mixture of calixarene 2 (150 mg, 0.23 mmol),
1,4-phenylenebis(boronic acid) (5, 38 mg, 0.23 mmol), tetrakis-
(triphenylphosphine)palladium(0) (173 mg, 0.15 mmol), anhy-
drous toluene (5 mL), and anhydrous CH3OH (0.5 mL) was
stirred at 100 °C for 15 min and then treated with 2 M aqueous
Na2CO3 (1 mL). The suspension was stirred at 100 °C for 3 days,
cooled to rt, diluted with CH2Cl2 (10 mL), washed with water
(10 mL), 1 M HCl (10 mL), and water (10 mL), dried (Na2SO4),
and concentrated. The residue was triturated with boiling Et2O
(3 × 5 mL) to give 7 (91 mg, 61 wt %) as a brown solid: 1H
NMR δ 1.18-1.38 (m, 6 H, CH3CH2CH2), 1.98-2.15 (m, 4 H,
CH3CH2CH2), 3.28-3.47 and 4.21-4.41 (m, 8 H, ArCH2Ar),
3.90-4.06 (m, 4 H, CH3CH2CH2), 6.70-7.90 (m, 20 H, Ar and
OH); 13C NMR δ 10.9 (CH3CH2CH2), 23.5 (CH3CH2CH2), 31.2-
31.7 (ArCH2Ar), 78.4 (CH3CH2CH2), 126.8-135.5 (Ar).
4-Styr ylbor on ic Acid (11). To a warmed (40 °C), stirred
suspension of magnesium (1.20 g, 49.36 mmol) in anhydrous
THF (10 mL) was slowly added a solution of 4-bromostyrene
(6.06 g, 33.12 mmol) in anhydrous THF (20 mL). During the
addition, the oil bath was removed in order to keep the mixture
under a gentle reflux. The suspension was refluxed for 1 h,
cooled to -78 °C, and treated with trimethyl borate (4.57 g, 43.95
mmol). The mixture was stirred at rt for 20 min, diluted with
Et2O (100 mL), washed with 1 M HCl (50 mL) and water (50
mL), dried (Na2SO4), and concentrated. The residue was
crystallized with Et2O-hexane to give 11 (3.80 g, 78%) as a
white solid: mp 190 °C (dec); 1H NMR (D2O + NaOH) δ 4.97 (d,
1 H, J ) 11.6 Hz, CHdCH2), 5.57 (d, 1 H, J ) 18.2 Hz, CHd
CH2), 6.53 (dd, 1 H, J ) 11.6 Hz and J ) 18.2 Hz, CHdCH2),
7.15 (d, 2 H, J ) 8.3 Hz, Ar), 7.28 (d, 2 H, J ) 8.3 Hz, Ar). The
NMR spectra in CDCl3 and the elemental analysis indicated that
11 was a mixture of anhydride and acid derivatives. These
findings have been already reported for other arylboronic
acids.12b
25-Hyd r oxy-26,27,28-tr ip r op oxyca lix[4]a r en e (8). To a
stirred solution of 25,26,27,28-tetrahydroxycalix[4]arene (2.00
g, 4.70 mmol) in anhydrous DMF (40 mL) was added Ba(OH)2‚
8H2O (5.20 g, 16.48 mmol), BaO (1.10 g, 7.17 mmol), and after
15 min, n-propyl iodide (13.8 mL, 141.5 mmol). The mixture
was stirred at rt for 6 h, diluted with CH2Cl2 (100 mL), washed
with water (3 × 50 mL), dried (Na2SO4), and concentrated. The
residue was eluted from a column of silica gel with 4:1 cyclo-
hexane-CH2Cl2 to give 8 (1.22 g, 47%) as a white solid: mp 101-
Compound 11 was heated at 100 °C for 10 min in neat 1,2-
ethanediol (4 equiv), cooled to rt, diluted with CH2Cl2, washed
three times with H2O, dried (Na2SO4), and concentrated. The
residue was distilled using a Kugelrohr apparatus (80 °C, 0.1
mbar) to give pure ethylene 4-styrylboronate: 1H NMR δ 4.39
1
102 °C; H NMR δ 0.96 (t, 3 H, J ) 7.0 Hz, CH3CH2CH2), 1.13
(t, 6 H, J ) 7.0 Hz, CH3CH2CH2), 1.90-1.93 (m, 4 H, CH3CH2-
CH2), 2.24-2.29 (m, 2 H, CH3CH2CH2), 3.22 and 4.44 (2 d, 8 H,
J ) 13.2 Hz, ArCH2Ar), 3.30 and 4.39 (2 d, 8 H, J ) 13.7 Hz,

Notes
J . Org. Chem., Vol. 63, No. 25, 1998 9539
(s, 4 H, 2 CH2), 5.31 (d, 1 H, J ) 11.0 Hz, CH2d), 5.83 (d, 1 H,
J ) 17.5 Hz, CH2d), 6.74 (dd, 1 H, J ) 11.0, 17.5 Hz, CHd),
7.78 and 7.44 (2 bd, 4 H, J ) 8.0 Hz, Ph); 13C NMR δ 65.9 (CH2),
115.0 (CH2d), 125.6 (2 C-3), 127.0 (C-1), 135.0 (2 C-2), 136.7
(CHd), 140.3 (C-4). Anal. Calcd for C8H9BO2: C, 64.94; H, 6.13.
Found: C, 65.18; H, 6.19.
5.25 (d, 2 H, J ) 11.2 Hz, CHdCH2), 5.74 (d, 2 H, J ) 18.7 Hz,
CHdCH2), 6.70-6.78 (m, 4 H, CHdCH2, Ar), 7.10 (d, 4 H, J )
7.3 Hz, Ar), 7.29 (s, 4 H, Ar), 7.46 (q, 8 H, J ) 8.0 Hz, Ar), 8.52
(s, 2 H, OH); 13C NMR δ 10.0 (CH3CH2CH2), 22.5 (CH3CH2CH2),
30.7 (ArCH2Ar), 77.5 (CH3CH2CH2), 112.3 (CHdCH2), 124.4,
125.5, 126.1, 127.5, 128.2, 132.5, 135.6, 150.9, 152.3 (CHdCH2,
25,27-Dih yd r oxy-26,28-d ip r op oxy-5,17-bis(4-styr yl)ca lix-
[4]a r en e (12). A mixture of calixarene 2 (250 mg, 0.37 mmol),
4-styrylboronic acid (11, 54 mg, 0.37 mmol), tetrakis(tri-
phenylphosphine)palladium(0) (280 mg, 0.25 mmol), anhydrous
toluene (2.5 mL), and anhydrous CH3OH (1 mL) was stirred at
100 °C for 15 min and then treated with 2 M aqueous Na2CO3
(1 mL). The suspension was stirred at 100 °C for 4 h, cooled to
rt, diluted with CH2Cl2 (10 mL), washed with 2 M aqueous Na2-
CO3 (5 mL) containing 0.5 mL of concentrated NH3 and then
water (10 mL), dried (Na2SO4), and concentrated. The residue
was eluted from a column of silica gel with 4:1 CCl4-CH2Cl2
(containing 0.3% Et3N) to give 12 (80 mg, 30%) as a white solid:
Ar); MALDI-TOF MS for C50H48O4 (712.93) m/z ) 735.8 [M+
Na], 751.9 [M+ + K].
+
Ack n ow led gm en t. We thank Mr. P. Formaglio
(University of Ferrara, Italy) for NMR measurements.
Su p p or tin g In for m a tion Ava ila ble: 1H NMR spectra of
compounds 2, 3, 5, and 8-12 as evidence of the degree of purity
1
and H and 13C NMR spectra of the cyclic ethylene esters of 5
and 11 (12 pages). This material is contained in libraries on
microfiche, immediately follows this article in the microfilm
version of the journal, and can be ordered from the ACS; see
any current masthead page for ordering information.
1
mp 239-240 °C; H NMR δ 1.33 (t, 6 H, J ) 7.3 Hz, CH3CH2-
CH2), 2.04-2.13 (m, 4 H, CH3CH2CH2), 3.46 and 4.38 (2 d, 8 H,
J ) 13.7 Hz, ArCH2Ar), 4.02 (t, 4 H, J ) 7.3 Hz, CH3CH2CH2),
J O980868W