Stereospecific radical polymerization of substituted benzyl muconates in the solid state under topochemical control

Article abstract of DOI:10.1055/s-2005-865320

We have successfully controlled the stereochemical structure of diene polymers during radical polymerization in the solid state under UV and γ-ray radiation. The polymerization of the substituted benzyl muconates occurred via a crystal lattice controlled reaction mechanism. The polymerization is controlled by not only diisotactic and disyndiotactic, but also meso and racemo structures to afford various kinds of stereoregular polymers. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2005-865320

PAPER
1479
Stereospecific Radical Polymerization of Substituted Benzyl Muconates in the
Solid State Under Topochemical Control
S
olid-State Polym
e
k
rization of
S
i
ubstitu
k
ted Benzyl
M
a
uconate
s
zu Matsumoto,*a Toshihiro Tanaka,a,c Kunio Okab
a
Department of Applied Chemistry, Graduate School of Engineering, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka 558-8585,
Japan
Fax +81(6)66052981; E-mail: matsumoto@a-chem.eng.osaka-cu.ac.jp
Research Institute for Advanced Science and Technology, Osaka Prefecture University, Gakuencho 1-2, Sakai, Osaka 599-8570, Japan
Chemical Resources Laboratory, Tokyo Institute of Technology, R1-5, 4259, Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
b
c
Received 15 February 2005
This paper is dedicated to Prof. B. Giese on the occasion of his 65th birthday.
CO2R
CO2NH3R'
Abstract: We have successfully controlled the stereochemical
R'H3NO2C
structure of diene polymers during radical polymerization in the sol-
id state under UV and g-ray radiation. The polymerization of the
substituted benzyl muconates occurred via a crystal lattice con-
trolled reaction mechanism. The polymerization is controlled by not
only diisotactic and disyndiotactic, but also meso and racemo struc-
CO2NH3R'
CO2R
CO2NH3R'
X
X
hν
tures to afford various kinds of stereoregular polymers.
solid state
X
X
n
meso-diisotactic-trans-2,5-polymer
X = CO2R or CO2NH3R'
Key words: crystal engineering, controlled radical polymerization,
solid-state reaction, stereoregularity, topochemical reaction
CH2CH3
CH2
R =
CH2
Cl
CH2
Br
The control of stereochemical chain structures is one of
the most important topics for polymer syntheses since the
first discovery of stereoregular polymers in the 1950s by
Natta et al.1 The control of propagation is carried out by
the coordination of a chain end and a reacting monomer to
the metal center of a catalyst during the metal-catalyzed
polymerization of various kinds of vinyl and diene mono-
mers. In contrast, a radical chain-end dynamically rotates
and therefore takes several preferred conformations dur-
ing the free-radical polymerization,2 leading to atactic
polymer formation in most cases. In recent years, ste-
reospecific free-radical polymerization processes in the
presence of a Lewis acid3 or template4 was reported in ad-
dition to several successful radical polymerizations under
substrate5 and chiral-auxiliary6 control, in which the con-
formation of a radical chain end and the addition of mono-
mers are highly controlled. Polymer crystal engineering
also intensively fascinates us for the control of the chain
structures as well as the polymer chain assembly in the
solid state.7 During the past decade, we have demonstrat-
ed that a large number of 1,3-diene monomers proceed in
the crystalline state to give polymer crystals with a highly
controlled chain structure. For example, muconic and sor-
bic acids as well as other diene carboxylic acids as the es-
ter, amide, and ammonium derivatives provide a
stereoregular trans-1,4-diisotactic diene polymer during
the solid-state polymerization via a topochemically con-
trolled reaction mechanism. Topochemical polymeriza-
tion is applied to many unsaturated monomers other than
1,3-diene monomers on the basis of the common to-
R' =
CO2R
RO2C
CO2R
CO2R
CO2R
CO2R
hν
solid state
CO2R
CO2R
n
racemo-disyndiotactic-trans-2,5-polymer
R =
CH2
OCH3
CH2
OCH2CH3
CO2NH3R'
CO2NH3R'
hν
CO2NH3R' CO2NH3R'
solid state
CO2NH3R' CO2NH3R'
n
racemo-diisotactic-trans-2,5-polymer
R' =
CH2
CO2R
CO2R
CO2R
CO2R
hν
solid state
CO2R
CO2R
n
meso-disyndiotactic-trans-2,5-polymer
SYNTHESIS 2005, No. 9, pp 1479–1490
x
x
.
x
x
.2
0
0
5
R =
CH2
OCH3
Advanced online publication: 18.04.2005
DOI: 10.1055/s-2005-865320; Art ID: C00805SS
© Georg Thieme Verlag Stuttgart · New York
Scheme 1

1480
A. Matsumoto et al.
PAPER
pochemical polymerization principles.8 We have already regular diene polymers with a different stereochemical
succeeded in controlling the monomer stacking in the structure through the controlled radical polymerization in
crystals with intermolecular interactions such as robust the solid state.
two-dimensional hydrogen bond networks as well as CH/
The stereospecific synthesis of muconic esters is neces-
sary for the design and control of polymer structures be-
cause E/Z-isomerism significantly influences the
p or CH/O interactions as a weak hydrogen bond to design
the solid-state polymerization of 1,3-diene monomers.9–12
During the solid-state polymerization, an isotactic poly- photoreaction behavior in the crystalline state. In general,
mer is exclusively produced because monomer molecules the Z,Z-isomers of the 1,3-diene compounds, such as the
usually tend to get arranged with a translational molecular muconic derivatives, readily isomerize into the corre-
packing in the crystals.13 For example, the ethyl,14 4-chlo- sponding E,Z- and E,E-isomers upon heating or during
robenzyl,10 or 4-bromobenzyl10 esters of (Z,Z)-muconic photoirradiation in the absence or presence of a catalyst,17
acid were confirmed to stack translationally in a column but the quantitative reverse reaction forming the Z,Z-iso-
in the monomer crystals, and undergo topochemical poly- mers hardly occurred. Table 1 summarizes the results for
merization during photoirradiation leading to the forma- the synthesis of benzyl muconates using (Z,Z)-muconic
tion of a diisotactic polymer (Scheme 1). The other acid as the starting material. (Z,Z)-Muconic acid is well-
muconic and sorbic derivatives such as the amide and am- known as one of the important intermediates in a natural
monium derivatives also provide diisotactic polymers via metabolic system of aromatic compounds,18 and a syn-
the topochemically controlled propagation of translation- thetic process from D-glucose using microorganisms has
ally stacked monomers in the crystals.7 Recently, we also been developed.19 When muconic esters were prepared by
found that a disyndiotactic polymer is produced by the al- conventional methods, it was difficult to efficiently obtain
ternate stacking of bis(4-methoxybenzyl) (Z,Z)- or (E,E)- Z,Z-isomers without E,Z-isomerization. For example, the
muconate through CH/p intermolecular interactions in a dehydration of muconic acid and 4-bromobenzyl alcohol
column formed in the monomer crystals.15 Furthermore, in the presence of sulfuric acid at reflux in benzene for 3
all of the four possible kinds of stereoregular diene poly- hours resulted in the formation of the E,Z-isomer as the
mers have actually been fabricated by the translational major product; Z,Z/E,Z = 4:96. When the muconic acid
and alternate molecular stacking in the crystals in combi- chloride was prepared by the reaction with thionyl chlo-
nation with the molecular symmetry of the geometric iso- ride in dichloromethane at reflux for one hour, and al-
mers of the muconic derivatives. We found that not only lowed to react with 4-bromobenzyl alcohol in the
the (Z,Z)- and (E,E)-1,3-diene monomers, but also the presence of triethylamine, the ester was isolated as the
(E,Z)-diene monomers undergo topochemical polymer- mixture of three isomers; yield: 28%, Z,Z/E,Z/E,E =
ization to provide the different kinds of stereoregular 82:14:4. The esters were produced in a higher yield at a
polymers.16
higher temperature and for a longer time, but the contents
of E,Z- and E,E-isomers increased. The Z,Z-isomer was
isolated by silica gel chromatography, but the E,Z- and
E,E-isomers are hardly separated from each other.
In this study, we have investigated the crystal structure
and solid-state polymerization of alkoxy-substituted ben-
zyl muconates as well as several related ester monomers,
as shown in Figure 1. We report the synthesis of stereo-
CO2R
CO2R
RO2C
CO2R
CO2R
CO2R
Z,Z
E,E
E,Z
R =
OCH3
CH3O
CH2
CH2
CH2
OCH3
2-MeO
3-MeO
4-MeO
4-NO2
CH2
OCH2CH3
CH2
O(CH2)3CH3
CH2
NO2
4-EtO
4-BuO
4-Br
CH2CH3
EMU
CH2
Cl
CH2
Br
4-Cl
Figure 1 Chemical structure of muconates used in this study
Synthesis 2005, No. 9, 1479–1490 © Thieme Stuttgart · New York

PAPER
Solid-State Polymerization of Substituted Benzyl Muconates
1481
To carry out the reactions under milder conditions for sup- ly depends on not only the substituents on a benzyl group
pressing the isomerization, we first adopted a quaternary but also the E,Z-configuration of the muconate. The type
ammonium carboxylate salt as the phase-transfer catalyst of a reaction for the monomers in Table 2 are divided into
in a two-phase system for the esterification. When a weak several groups; (i) polymerized under both UV and g-ra-
base was used, the isomerization was suppressed; Z,Z/ diation, (ii) isomerized under UV irradiation and polymer-
E,Z = 82:18. Next, we tested the reaction of potassium ized under g-radiation, (iii) isomerized under UV
muconate with benzyl bromides in the presence of a base irradiation and no reaction under g-radiation, (iv) no reac-
in a highly polar solvent such as hexamethylphosphor- tion under UV irradiation and polymerized under g-radia-
amide or N-methylpyrrolidone. As a result, the acid was tion, and (v) no reaction under both UV and g-radiation.
converted into the corresponding ester without any E,Z-
isomerization. The Z,Z-isomers were exclusively obtained
in a high yield for various kinds of substituted benzyl es-
ters and no E,Z- and E,E-isomers were detected in the
crude products (Table 1), whereas a reaction with benzyl
chloride provided a mixture of Z,Z- and E,Z-isomers.
Thus, the reaction of potassium muconate with benzyl
bromides in a polar solvent is a convenient method for the
Some Z,Z-monomers underwent a solid-state polymeriza-
tion and produced a polymer in a high yield under both
UV and g-ray radiation. The other Z,Z-derivatives isomer-
ized to the corresponding E,E-isomers under UV irradia-
tion, but they provided a different product under g-
radiation; atactic and stereoregular polymers or no reac-
tion. Isomerization was specific to the reaction of the Z,Z-
compounds and no isomerization occurred for the E,E-
stereoselective synthesis of Z,Z-derivatives, including
simple processes for the synthesis and isolation of the es-
ters (see experimental section).
and E,Z-derivatives. Several E,E-monomers were poly-
merized under UV and g-radiation, similar to the results of
the Z,Z-derivatives. Two of the E,Z-isomers had no reac-
The (E,Z)-muconates were directly prepared from (E,Z)- tion under UV irradiation, but the g-radiation resulted in
muconic acid in a method similar to that for the Z,Z-deriv- the formation of a polymer. Interestingly, the polymeriza-
atives, or separated from a mixture of the Z,Z- and E,Z- tion proceeded independent of the electronic nature of the
isomers by silica gel chromatography. For the preparation substituent on the benzyl group, the polymerization was
of the E,E-monomers, the crude products as the mixture of induced by the methoxy, ethoxy, chloro, bromo, and nitro
isomers were photoirradiated at room temperature in the substituents at the meta or para position. Several other de-
presence of a small amount of iodide as the isomerization rivatives were inert to both the UV and g-radiation. All the
catalyst.17 All the monomers were recrystallized from reactions of the (E,E)- and (E,Z)-muconates are classified
chloroform or any other appropriate solvent.
into categories (i) or (v), and (iv) or (v), respectively. The
(Z,Z)-muconates showed a complicated reaction behavior
depending on the position and structure of the substituents
due to several possible pathways, as shown in Scheme 2.
The isomerization and polymerization competitively pro-
ceeds for the reaction of the Z,Z-isomers. Nevertheless, ei-
ther an E,E-isomer or a polymer was obtained as the
product in each reaction. Namely, the reaction occurred
Table 2 summarizes the results of the solid-state reactions
for a series of substituted benzyl muconates under UV or
g-ray radiation. The reactivity and mechanism of the sol-
id-state reactions are determined by the style of the molec-
ular stacking in the crystals rather than the chemical
nature of the reactants. Therefore, the reaction pathway of
the substituted benzyl muconates in this study significant-
Table 1 Stereospecific Synthesis of Benzyl Muconates from (Z,Z)-Muconic Acida
RX (1.0–1.1 equiv)
Solventb
K2CO3
(equiv)
Time
(h)
Yield
(%)
Isomer
Z,Z/E,Z/E,E
c
c
4-Bromobenzyl bromide
4-Bromobenzyl bromide
4-Bromobenzyl bromide
4-Chlorobenzyl bromide
4-Ethoxybenzyl bromide
4-Nitrobenzyl bromide
Benzyl bromide
H2O–CH2Cl2
H2O–CH2Cl2
HMPA
2.2d
1.1
1.5
1.5
1.5
1.5
2
72
72
24
48
24
24
24
72
84
56
79
96
85
84
63e
78
30:70:0
82:18:0
ca. 100:0:0
ca. 100:0:0
ca. 100:0:0
ca. 100:0:0
ca. 100:0:0e
70:30:0
HMPA
HMPA
HMPA
NMP
4-Methoxybenzyl chloride
HMPA
1.5
a Reaction was carried out by stirring at room temperature.
b HMPA: hexamethylphosphoramide; NMP: N-methylpyrrolidone.
c With tetrabutylammonium hydrogensulfate.
d KOH was used.
e As isolated by recrystallization from MeOH.
Synthesis 2005, No. 9, 1479–1490 © Thieme Stuttgart · New York

1482
A. Matsumoto et al.
PAPER
with a high selectivity, being one of the characteristics of tion favorably proceeds via a radical chain mechanism.21
the solid-state reactions under a crystal-lattice control.
Under g-radiation, the formed radical species induces a
similar radical chain polymerization rather than isomer-
ization in the crystalline state. No isomerization during g-
radiation was confirmed by the NMR spectra of the recov-
ered monomers after polymerization at a lower reaction
dose.
We previously reported that several (Z,Z)-muconic deriv-
atives easily isomerize to the corresponding E,E-isomers
in the crystalline state without any formation of E,Z-iso-
mers as the side product, and that the reverse reaction does
not occur.20 This crystal-to-crystal one-way E,Z-isomer-
ization is induced by the excitation of diene compounds The X-ray crystallographic analyses of the monomer and
during the UV irradiation. When the adjacent monomer the polymer single-crystals reveal a relationship between
molecules are situated at the position appropriate for the the molecular stacking in the monomer crystals and the
topochemical polymerization, the solid-state polymeriza- stereochemical structure of polymers as well as the solid-
Table 2 Products for UV and g-Radiation of Substituted Benzyl Muconates in the Crystalline Statea
Monomer
Ar substituent
UV Irradiation
Product
g-Radiation
Reaction
typeb
Yield (%)
Product
Yield (%)
(Z,Z)-2-MeO
(Z,Z)-3-MeO
(Z,Z)-4-MeO
(Z,Z)-4-EtO
(Z,Z)-4-BuO
(Z,Z)-4-NO2
(Z,Z)-4-Cle
2-Methoxy
3-Methoxy
4-Methoxy
4-Ethoxy
4-n-Butoxy
4-Nitro
E,E-Isomer
E,E-Isomer
Polymer
18
4
No reaction
Polymerc,d
Polymer
–
iii
ii
i
55
93
95
57
31
97
87
–
ca. 100
Polymer
Polymer
ca. 100
i
E,E-Isomer
Polymer
Polymer
ca. 100
ii
i
Polymer
ca. 100
4-Chloro
4-Bromo
2-Methoxy
3-Methoxy
4-Methoxy
4-Ethoxy
4-n-Butoxy
4-Nitro
Polymer
Polymer
ca. 100
i
(Z,Z)-4-Bre
(E,E)-2-MeO
(E,E)-3-MeO
(E,E)-4-MeO
(E,E)-4-EtO
(E,E)-4-BuO
(E,E)-4-NO2
(E,E)-4-Cl
Polymer
Polymer
ca. 100
i
No reaction
Polymer
No reaction
Polymer
–
v
i
67
81
63
–
ca. 100
Polymer
Polymer
ca. 100
i
Polymer
Polymer
ca. 100
i
No reaction
No reaction
No reaction
No reaction
No reaction
No reaction
No reaction
No reaction
No reaction
No reaction
No reaction
No reaction
No reaction
No reaction
Polymerc
–
–
v
v
v
v
iv
v
iv
v
v
v
–
4-Chloro
4-Bromo
4-Methoxy
4-Ethoxy
4-n-Butoxy
4-Nitro
–
–
(E,E)-4-Br
–
–
(E,Z)-4-MeO
(E,Z)-4-EtO
(E,Z)-4-BuO
(E,Z)-4-NO2
(E,Z)-4-Cl
–
96
–
–
No reaction
Polymerc,d
No reaction
No reaction
No reaction
–
80
–
–
4-Chloro
4-Bromo
–
–
(E,Z)-4-Br
–
–
a Benzyl muconates were recrystallized from CHCl3. UV irradiation was carried out using a high-pressure Hg lamp (100 W) at a distance of 10
cm for 8 h at r.t. g-Radiation was carried out with 60Co at r.t. at a dose of 200 kGy. Polymers were isolated as insoluble products. The isomer-
ization conversion was determined by 1H NMR spectroscopy.
b i: polymerized under both UV and g-radiation; ii: isomerized under UV irradiation and polymerized under g-radiation; iii: isomerized under
UV irradiation and no reaction under g-radiation; iv: no reaction under UV irradiation and polymerized under g-radiation; v: no reaction under
both UV and g-radiation.
c The product was soluble in CHCl3. The yield was determined from the integration ratio of benzyl methylene protons in the 1H NMR spectra.
d Atactic polymer was obatined after the g-radiation polymerization at a dose of 200 kGy.
e Ref.10
Synthesis 2005, No. 9, 1479–1490 © Thieme Stuttgart · New York

PAPER
Solid-State Polymerization of Substituted Benzyl Muconates
1483
RO2C
CO2R
E,E-isomer
CO2R
n
stereoregular polymer
CO2R
CO2R
CO2R
Z,Z-isomer
CO2R
CO2R
CO2R
atactic polymer
n
CO2R
no reaction
Scheme 2
state polymerization reactivity. The crystal structures of
the monomers were determined at –70 °C to avoid the ef-
fect of the polymerization during X-ray measurements. A
comparison of the crystallographic data for the monomer
and polymer single crystals provides much information
regarding the solid-state polymerization mechanism.
The crystallographic results confirm a topochemical pro-
cess during the polymerization of the muconates in the
solid state. As a typical example, the crystal structures of
(Z,Z)-NO2 and poly[(Z,Z)-NO2] are shown in Figure 2,
which indicates translational monomer packing leading to
diisotactic polymer formation. Figure 3 shows the alter-
nate stacking resulting in a disyndiotactic polymer for
(Z,Z)-4-MeO and poly[(Z,Z)-4-MeO].15
Figure 2 Single-crystal structures of (Z,Z)-NO2 and poly[(Z,Z)-
NO2]; The monomer molecules are translationally stacked along the
crystallographic b axis of the crystal of Z,Z-NO2. Diisotactic polymer
chains are formed along the same axis during the polymerization.
Figure 4 shows intermolecular interaction forming the
translational and alternate molecular stacking in a colum-
nar structure in the crystals. In the alternate stacking struc-
ture, the CH/p interaction22 is important between the
methoxy methyl and the phenyl carbons of the benzyl
group. The zig-zag chain of the interaction is formed
along a monomer column, and it supports the alternate
stacking. A similar interaction is observed in the polymer
crystals. The weak intermolecular interactions are capable
of a variety of crystal structure formations by inducing a
different molecular stacking leading to the different tac-
ticity of the polymers. This is contrast to the formation of
exclusive translational molecular stacking for the ammo-
nium derivatives supported by a strong hydrogen bond
network, which has a robust and credible but inflexible
structure.23 Disyndiotactic polymers are obtained from the
4-methoxy and ethoxy derivatives by the alternate stack-
ing, and all the other polymers have a diisotactic structure
due to the translational stacking of the monomers. For ex-
ample, the 3-methoxy, 4-chloro-, 4-bromo-, and n-butoxy
derivatives translationally stack as well as the nitro-sub-
stituted one shown in Figure 2, resulting in the formation
of the diisotactic polymers.
The relationship between the molecular stacking in the
monomer crystals and the polymerization reactivity has
already been examined in detail in our previous study.7
The monomer stacking structures of the monomers used
in this study were also checked according to a general rule
for the polymerization of 1,3-diene monomers.8,24 We de-
termined the stacking distance (ds), the distance between
the reacting C2 and C5¢ carbons (dcc), and the tilt angles of
the molecular plane (q1 and q2) to estimate the polymer-
ization reactivity7 (Figure 5). These results are summa-
rized in Table 3. For all the polymerizable monomers, the
stacking distance was 4.7–5.5 Å, and the carbon-to-car-
bon distance for the reaction was 3.3–4.2 Å. In the mono-
mer crystal of (Z,Z)-3-MeO, the largest ds value (5.54 Å)
and dcc value (4.16 Å) were observed. Due to the structure
consisting of a poor molecular stacking in the monomer
crystals, no polymer was formed during the UV irradia-
tion. Even under g-radiation, the polymer formation pos-
sibly collapsed the crystal structure during the initial stage
of the polymerization, leading to the atactic polymer for-
mation.
Synthesis 2005, No. 9, 1479–1490 © Thieme Stuttgart · New York

1484
A. Matsumoto et al.
PAPER
Figure 4 Intermolecular interaction forming the translational mole-
cular stacking in the crystals: (a) (Z,Z)-4-Cl, (b) (Z,Z)-4-BuO, (c)
(Z,Z)-4-NO2; Intermolecular interaction forming the alternate mole-
cular stacking in the crystals: (d) (Z,Z)-4-MeO
Figure 3 Single-crystal structures of (Z,Z)-4-MeO and poly[(Z,Z)-4-
MeO]; The monomer molecules are alternately stacked along the cry-
stallographic b axis of the crystal of (Z,Z)-4-MeO (Ref.15). Disyndiot-
actic polymer chains are formed along the same axis during the
polymerization.
The polymers were highly crystalline and insoluble in or-
ganic solvents after they were isolated as the polymer
crystals by removing the unreacted monomer with any or-
ganic solvent. When the polymer crystals were once heat-
ed over their melting point in the bulk, or in a polar solvent
with a high boiling point, they were recovered as the
amorphous or partly crystalline polymers for the alkoxy-
substituted benzyl ester polymers. In contrast, the chloro- distance between the adjacent monomers in a column. q1 and q2 are the
and bromo-substituted polymers were insoluble after
heating because of their high melting temperature and
strong intermolecular interaction. The polymer crystals
Figure 5 Stacking model for the muconate derivatives in the cry-
stalline state and the definition of stacking parameters used for the
prediction of the topochemical polymerization reactivity. dcc is the in-
termolecular distance between the 2- and 5¢-carbons. ds is the stacking
angles between the stacking direction and the molecular plane in or-
thogonally different directions. The view from direction I is parallel
to a vector through the 2- and 5-carbons of the diene moieties (Ref.7).
are uniquely obtained by the solid-state polymerization,
while partly crystalline polymers are prepared by the crys-
tallization of preformed polymers by a conventional
method. They show physical properties different from
each other.
The narrow and single peaks for each carbon observed in
13C NMR spectra for the polymers obtained by the g-radi-
ation polymerization of substituted benzyl muconates and
the subsequent treatment by heating. This indicates the
formation of a stereoregular polymer during the polymer-
Synthesis 2005, No. 9, 1479–1490 © Thieme Stuttgart · New York

PAPER
Solid-State Polymerization of Substituted Benzyl Muconates
1485
ization, except for the polymerization of (Z,Z)-3-MeO and bons, 129.6–129.9 and 129.3–129.4 ppm for the CH=CH
(E,Z)-4-BuO. These two monomers provided no polymer carbons, 51.3–52.0 and 50.7–50.9 ppm for the CH car-
under UV-irradiation and an amorphous polymer during bons, respectively, independent of the kind of ester groups
g-radiation polymerization due to the poor molecular and diisotactic or disyndiotactic structures. A difference
stacking in the monomer crystals.
in a chemical shift depending on the meso and racemo
structures was also observed for polyfumarates with
alkoxycarbonyl substituents on the vicinal carbons in the
polymer main chain, as was previously reported.25 The
stereochemical structure of the polymers can directly be
determined by a single crystal structure analysis in some
cases. However, NMR spectroscopy is a convenient meth-
od for determining the stereochemical structure of the
polymers, because polymer single crystals with a high
quality for an X-ray experiment are not always successful-
ly obtained.
There are four types of possible stereoregular structures
for each trans-1,4-polymer of 1,4-disubstituted
butadiene10 (Scheme 1). In general, the stereochemistry of
polymers is represented by two kinds of relationships as
follows: one is the relative configuration between the two
repeating monomer units, diisotactic and disyndiotactic
polymers, and the other is the relative configuration be-
tween the vicinal carbon centers, being represented by the
meso and racemo. The stereochemical structure of the
polymers produced during the topochemical polymeriza-
tion is designed on the basis of the E,Z-configuration and We further tried to synthesize stereoregular polymers with
the stacking of the monomers. When the corresponding different tacticities but the same ester alkyl group. The
E,Z-monomers with a different symmetrical structure un- monomer stacking structure and the tacticity of the ob-
dergo topochemical polymerization, the produced poly- tained polymers by topochemical polymerization signifi-
mer has a stereoregular structure different from that cantly depended on the structure of the ester alkyl groups.
obtained from the Z,Z- and E,E-monomers. Actually, the As a result, it is very hard to obtain different stereoregular
alternate stacking of bis(4-methoxybenzyl) (E,Z)-mucon- polymers from the same monomer by polymerization.
ate resulted in the formation of a meso-disyndiotactic Therefore, we adopted the polymer transformation from
polymer.
the various benzyl ester polymers to the ethyl ester poly-
mers with different tacticities. The benzyl esters were
readily hydrolyzed and produced poly(muconic acid)s,
which were dissolved in ethanol as the triethylammonium
salt and then reacted with ethanol, leading to the quantita-
tive transformation as ethyl esters. Consequently, the
Table 4 summarizes the comparison and the chemical
shifts for the stereoregular polymers obtained from vari-
ous muconic esters. The meso and racemo structure can be
determined based on the absolute value of the chemical
shift; 170.2–170.5 and 170.9–171.3 ppm for the C=O car-
Table 3 Monomer Stacking Parameters for Topochemically Polymerizable Substituted Benzyl Muconates in the Monomer Crystalsa
Monomer
Polymerization reactivity
ds
dcc
q1
q2
UV
Translational Stacking Monomers
g-Ray
(Å)
(Å)
(degree)
(degree)
(Z,Z)-4-BuO
(Z,Z)-4-Clc
no
yes
yes
yes
yes
yes
yesb
4.86
5.06
5.14
5.21
5.24
5.54
3.78
3.48
3.38
3.89
3.61
4.16
88
78
78
72
75
65
52
43
40
49
44
46
yes
yes
yes
yes
no
(E,E)-3-MeO
(Z,Z)-4-Brc
(Z,Z)-4-NO2
(Z,Z)-3-MeO
Alternate Stacking Monomers
d
d
(Z,Z)-4-MeO
(Z,Z)-4-EtO
(E,E)-4-MeO
(E,E)-4-EtO
(E,Z)-4-MeO
yes
yes
yes
yes
yes
yes
4.74
4.83
4.87
4.82
5.39
3.44
3.25
3.32
3.25
3.90
–
–
d
d
yes
yes
yes
no
–
–
d
d
–
–
d
d
–
–
d
d
–
–
a dcc: Distance between the reacting C2 and C5¢ carbons, ds: stacking distance, q1, q2: tilt angles of the molecular plane.
b Crystals collapsed during the polymerization.
c Ref.10
d Not determined because of alternate stacking.
Synthesis 2005, No. 9, 1479–1490 © Thieme Stuttgart · New York

1486
A. Matsumoto et al.
PAPER
Table 4 13C NMR Chemical Shifts for Stereoregular Muconate Polymers with Different Tacticities
Polymer
Tacticity
Chemical shift, d (CDCl3) at r.t.
C=O
CH=
CH
Poly[(Z,Z)-4-BuO]
Poly[(E,E)-3-MeO]
Poly[(E,Z)-4-MeO]
Poly[(Z,Z)-4-MeO]
Poly[(E,E)-4-MeO]
Poly[(Z,Z)-4-EtO]
Poly[(E,E)-4-EtO]
Poly(EMU)
meso-Diisotactic
170.28
170.20
170.16
170.95
170.94
170.87
170.89
170.48
170.46
171.32
129.74
129.71
129.85
129.31
129.38
129.31
129.30
129.59
129.71
129.37
51.27
51.74
51.61
50.74
50.71
50.85
50.85
52.04
51.45
50.61
meso-Diisotactic
meso-Disyndiotactic
racemo-Disyndiotactic
racemo-Disyndiotactic
racemo-Disyndiotactic
racemo-Disyndiotactic
meso-Diisotactic
meso-Disyndiotactica
racemo-Disyndiotacticb
a Derived from poly[(E,Z)-4-MeO] by polymer transformation.
b Derived from poly[(E,E)-4-MeO] by polymer transformation.
mixture was poured into H2O (100 mL), and the crude product was
extracted with CHCl3 (2 × 100 mL). The combined CHCl3 extracts
were washed with H2O, dried (Na2SO4), and evaporated under re-
duced pressure to provide a crude white solid. The solid was sub-
jected to short-path silica gel column chromatography with CHCl3,
to provide bis(4-bromobenzyl)muconate; yield: 20.1 g (84%); iso-
mer ratio: Z,Z/E,Z = 30:70 (determined by 1H NMR spectroscopy).
chemical shifts for the poly(EMU)s with various tactici-
ties also supported the same conclusion (Table 4). The
physical properties of the substitiuted benzyl and ethyl es-
ters with different tacticities are now under investigation.
The results will be reported elsewhere in the future togeth-
er with details for the transesterification of the polymers.
Method B; Using Hexamethylphosphoramide: To (Z,Z)-muconic
acid (2.1 g, 15 mmol) in hexamethylphosphoramide (20 mL) in a
100-mL flask equipped with a CaCl2 tube were added 4-ethoxyben-
zyl bromide (6.6 g, 33 mmol) and K2CO3 (4.4 g, 32 mmol) and
stirred at r.t. for 1 d. The reaction mixture was poured into H2O (300
mL), and the crude product was extracted with CHCl3 (2 × 150 mL).
The combined CHCl3 extracts were washed with H2O, dried
(Na2SO4), and evaporated under reduced pressure. To precipitate
the 4-ethoxybenzyl esters, H2O and MeOH were added to the resid-
ual liquid. The precipitated white solid was filtered and dried under
reduced pressure; yield: 5.23 g (85%).
Historically, the isotactic polymerization of vinyl mono-
mers was followed by syndiotactic one, as seen in the de-
velopment of the stereospecific polymerization of
styrene,26 propylene,27 methacrylates,28 and crotonates.29
More sophisticated catalysts are required for the control of
the syndiotactic propagation during a catalytically con-
trolled polymerization. For diene polymerization with a
catalytic control, Takasu et al.30 recently reported the syn-
thesis of a predominantly disyndiotactic poly(alkyl sor-
bate) by anionic polymerization. However, the synthesis
of diene polymers with a highly controlled stereochemical
structure has been still one of the challenging topics, in-
cluding polymuconates and polysorbates.31 We have suc-
cessfully demonstrated the stereochemical control of
diene polymers, the control of not only diisotactic and di-
syndiotactic but also meso and racemo structures, during
the solid-state polymerization under crystal-lattice con-
trol, which has a feature different from those for the con-
trolled polymerization in solution.
Bis(2-methoxybenzyl) (Z,Z)-Muconate [(Z,Z)-2-MeO]
Colorless plates; mp 87.3–88.0 °C (CHCl3).
IR (KBr): 1589 (C=C), 1713 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 7.93 (m, CH=CHCO2R, 2 H),
7.29–7.35 (m, C6H4, 4 H), 6.88–6.98 (m, C6H4, 4 H), 6.03 (m,
CH=CHCO2R, 2 H), 5.24 (s, CH2, 4 H), 3.85 (s, CH3, 6 H).
13C NMR (100 MHz, CDCl3): d = 165.58 (C=O), 157.58 (C6H4),
138.10 (CH=), 129.91, 129.74, 124.18, 123.93, 120.43, and 110.46
(C6H4 and CH=), 61.82 (CH2), 55.42 (CH3).
UV (MeCN): lmax = 266 nm (e = 26800).
Bis(3-methoxybenzyl) (Z,Z)-Muconate [(Z,Z)-3-MeO]
Colorless prisms; mp 57.1–57.9 °C (CHCl3).
Esterification of (Z,Z)-Muconic Acid; Bis(4-bromobenzyl) Mu-
conate; Typical Procedures
Method A;Using a Phase-Transfer Catalyst: (Z,Z)-Muconic acid
(711 mg, 5.0 mmol), Bu4NHSO4 (3.73 g, 11 mmol), and KOH (1.23
g, 22 mmol) were dissolved in 1,2-dichloroethane (20 mL) and H2O
(20 mL) in a 100 mL flask. 4-Bromobenzyl bromide (2.75 g, 11
mmol) was added and the mixture stirred at r.t. for 3 d. The reaction
IR (KBr): 1588 (C=C), 1718 (C=O).
1H NMR (400 MHz, CDCl3): d = 7.93 (m, CH=CHCO2R, 2 H),
7.24–7.31 (m, C6H4, 4 H), 6.85–6.97 (m, C6H4, 4 H), 6.03 (m,
CH=CHCO2R, 2 H), 5.16 (s, CH2, 4 H), 3.81 (s, CH3, 6 H).
Synthesis 2005, No. 9, 1479–1490 © Thieme Stuttgart · New York

PAPER
Solid-State Polymerization of Substituted Benzyl Muconates
1487
13C NMR (100 MHz, CDCl3): d = 165.32 (C=O), 159.77, 138.37,
137.18, 129.68, 124.02, 120.41, 113.83 and 113.68 (C6H4 and
CH=), 66.16 (CH2), 55.25 (CH3).
13C NMR (100 MHz, CDCl3): d = 165.89 (C=O), 157.60 (C6H4),
141.05 (CH=), 129.89, 129.79, 128.37, 123.88, 120.45, and 110.51
(C6H4 and CH=), 62.20 (CH2), 55.45 (CH3).
UV (MeCN): lmax = 267 nm (e = 25600).
UV (MeCN): lmax = 266 nm (e = 35400).
Bis(4-methoxybenzyl) (Z,Z)-Muconate [(Z,Z)-4-MeO]
Colorless plates; mp 82.9–83.2 °C (CHCl3).
Bis(3-methoxybenzyl) (E,E)-Muconate [(E,E)-3-MeO]
Colorless plates; mp 75.3–75.7 °C (CHCl3).
IR (KBr): 1584 (C=C), 1717 cm–1 (C=O).
IR (KBr): 1605 (C=C), 1716 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 7.91 (m, CH=CHCO2R, 2 H),
7.30–7.35 (m, C6H4, 4 H), 6.88–6.93 (m, C6H4, 4 H), 6.00 (m,
CH=CHCO2R, 2 H), 5.13 (s, CH2, 4 H), 3.82 (s, CH3, 3 H).
1H NMR (400 MHz, CDCl3): d = 7.25–7.34 (m, CH=CHCO2R and
C6H4, 6 H), 6.86–6.97 (m, C6H4, 4 H), 6.24 (m, CH=CHCO2R, 2 H),
5.19 (s, CH2, 4 H), 3.81 (s, CH3, 6 H).
13C NMR (100 MHz, CDCl3): d = 165.48 (C = O), 159.70 (C6H4),
138.21 (CH = ), 130.18, 127.80, and 124.11 (C6H4), 114.00
(CH = ), 66.13 (CH2), 55.30 (CH3).
13C NMR (100 MHz, CDCl3): d = 165.61 (C=O), 159.75 (C6H4),
141.21 (CH=), 137.08, 129.69, 128.87, 128.23, 120.48, and 113.78
(C6H4 and CH=), 66.56 (CH2), 55.25 (CH3).
UV (MeCN): lmax = 264 nm (e = 261000).
UV (MeCN): lmax = 266 nm (e = 35400).
Bis(4-ethoxybenzyl) (Z,Z)-Muconate [(Z,Z)-4-EtO]
Colorless plates; mp 91.9–92.5 °C (CHCl3).
Bis(4-methoxybenzyl) (E,E)-Muconate [(E,E)-4-MeO]
Colorless plates; mp 119.8–121.8 °C (CHCl3).
IR (KBr): 1585 (C=C), 1717 cm–1 (C=O).
IR (KBr): 1612 (C=C), 1713 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 7.90 (m, CH=CHCO2R, 2 H),
7.28–7.32 (m, C6H4, 4 H), 6.86–6.90 (m, C6H4, 4 H), 5.99 (m,
CH=CHCO2R, 2 H), 5.11 (s, OCH2, 4 H), 4.03 (q, 4 H, CH2CH3),
1.41 (t, CH2CH3, 6 H).
13C NMR (100 MHz, CDCl3): d = 165.50 (C=O), 159.06, 138.19,
130.17, 127.58, 124.11, and 114.49 (C6H4 and CH=), 66.16
(OCH2), 63.46 (CH2CH3), 14.79 (CH2CH3).
1H NMR (400 MHz, CDCl3): d = 7.28–7.34 (m, CH=CHCO2R and
C6H4, 6 H), 6.92–6.88 (m, C6H4, 4 H), 6.20 (m, CH=CHCO2R, 2 H),
5.14 (s, CH2, 4 H), 3.81 (s, CH3, 4 H).
13C NMR (100 MHz, CDCl3): d = 165.76 (C=O), 159.77 (C6H4),
141.08 (CH=), 130.27, 128.31, and 127.70 (C6H4), 114.00 (CH=),
65.56 (CH2), 55.30 (CH3).
UV (MeCN): lmax = 263 nm (e = 28000).
UV (MeCN): lmax = 266 nm (e = 28500).
Bis(4-ethoxybenzyl) (E,E)-Muconate [(E,E)-4-EtO]
Bis(4-butoxybenzyl) (Z,Z)-Muconate [(Z,Z)-4-BuO]
Colorless plates; mp 126.5–127.2 °C (CHCl3).
Colorless plates; mp 82.7–83.2 °C (CHCl3).
IR (KBr): 1593 (C=C), 1718 cm–1 (C=O).
IR (KBr): 1613 (C=C), 1713 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 7.30–7.37 (m, CH=CHCO2R and
C6H4, 6 H), 6.89–6.93 (m, C6H4, 4 H), 6.22 (m, CH=CHCO2R, 2 H),
5.16 (s, OCH2, 4 H), 4.05 (q, CH2CH3, 4 H), 1.43 (s, CH2CH3, 6 H).
13C NMR (100 MHz, CDCl3): d = 165.79 (C=O), 159.15, 141.08,
130.27, 128.33, 127.50, and 114.52 (CH= and C6H4), 66.61 and
63.48 (OCH2 and CH2CH3), 14.81 (CH2CH3).
1H NMR (400 MHz, CDCl3): d = 7.90 (m, CH=CHCO2R, 2 H),
7.28–7.31 (m, C6H4, 4 H), 6.86–6.89 (m, C6H4, 4 H), 5.99 (m,
CH=CHCO2R, 2 H), 5.11 (s, OCH2, 4 H), 3.96 (t, 4 H,
CH2CH2CH2CH3), 1.72–1.80 (m, 4 H, CH2CH2CH2CH3), 1.43–
1.54 (m, 4 H, CH2CH2CH2CH3), 0.97 (t, 6 H, CH2CH2CH2CH3).
13C NMR (100 MHz, CDCl3): d = 165.50 (C=O), 159.29, 138.18,
130.15, 127.52, 124.13, and 114.52 (C6H4 and CH=), 67.71 and
66.18 (OCH2 and CH2CH2CH2CH3), 31.26 (CH2CH2CH2CH3),
19.22 (CH2CH2CH2CH3), 13.84 (CH2CH2CH2CH3).
UV (MeCN): lmax = 266 nm (e = 37000).
Bis(4-butoxybenzyl) (E,E)-Muconate [(E,E)-4-BuO]
Colorless plates; mp 108.0–108.8 °C (CHCl3).
UV (MeCN): lmax = 266 nm (e = 28900).
IR (KBr): 1613 (C=C), 1706 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 7.28–7.33 (m, CH=CHCO2R and
C6H4, 6 H), 6.87–6.90 (m, C6H4, 4 H), 6.19 (m, CH=CHCO2R, 2 H),
5.14 (s, OCH2, 4 H), 3.96 (q, CH2CH2CH2CH3, 4 H), 1.72–1.79 (m,
4 H, CH2CH2CH2CH3), 1.43–1.54 (m, 4 H, CH2CH2CH2CH3), 0.97
(t, 6 H, CH2CH2CH2CH3).
13C NMR (100 MHz, CDCl3): d = 165.79 (C=O), 159.38, 141.06,
130.25, 128.33, 127.44, and 114.54 (CH= and C6H4), 67.73 and
66.62 (OCH2 and CH2CH2CH2CH3), 31.26 (CH2CH2CH2CH3),
19.24 (CH2CH2CH2CH3), 13.85 (CH2CH2CH2CH3).
Bis(4-nitrobenzyl) (Z,Z)-Muconate [(Z,Z)-4-NO2]
Pale yellow plates; mp 174.1–175.2 °C (CHCl3).
IR (KBr): 1587 (C=C), 1712 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 8.21–8.26 (m, C6H4, 4 H), 7.96 (m,
CH=CHCO2R, 2 H), 7.52–7.56 (m, C6H4, 4 H), 6.09 (m,
CH=CHCO2R, 2 H), 5.29 (s, OCH2, 4 H).
UV (MeCN): lmax = 271 nm (e = 43100).
Bis(2-methoxybenzyl) (E,E)-Muconate [(E,E)-2-MeO]
Colorless plates; mp 140.9–141.3 °C (CHCl3).
UV (MeCN): lmax = 266 nm (e = 37900).
IR (KBr): 1614 (C=C), 1703 cm–1 (C=O).
Bis(4-nitrobenzyl) (E,E)-Muconate [(E,E)-4-NO2]
Pale yellow powder; mp 191.9–193.3 °C (CHCl3).
IR (KBr): 1616 (C=C), 1716 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 8.23–8.26 (m, C6H4, 4 H), 7.53–
7.56 (m, C6H4, 4 H), 7.40 (m, 2 H, CH=CHCO2R), 6.31 (m,
CH=CHCO2R, 2 H), 5.32 (s, OCH2, 4 H).
1H NMR (400 MHz, CDCl3): d = 7.26–7.36 (m, CH=CHCO2R and
C6H4, 6 H), 6.88–7.00 (m, C6H4, 4 H), 6.25 (m, CH=CHCO2R, 2 H),
5.27 (s, CH2, 4 H), 3.85 (s, CH3, 6 H).
Synthesis 2005, No. 9, 1479–1490 © Thieme Stuttgart · New York

1488
A. Matsumoto et al.
PAPER
13C NMR (100 MHz, CDCl3): d = 165.20 (C=O), 142.72, 141.60,
13C NMR (100 MHz, CDCl3): d = 165.93 and 165.07 (C=O), 159.31
(C6H4), 140.75 and 138.81 (CH=), 130.24, 130.15, 128.97, 127.69,
127.47, 124.54, and 114.52 (C6H4 and CH=), 67.69
(CH2CH2CH2CH3), 66.39 and 66.29 (OCH2), 31.26
128.49, 127.93, and 123.88 (CH= and C6H4), 65.19 (OCH2).
UV (MeCN): lmax = 269 nm (e = 51200).
(CH2CH2CH2CH3),
(CH2CH2CH2CH3).
19.22
(CH2CH2CH2CH3),
13.84
Bis(3-methoxybenzyl) (E,Z)-Muconate [(E,Z)-3-MeO]
Colorless liquid.
UV (MeCN): lmax = 266 nm (e = 31800).
IR (KBr): 1601 (C=C), 1722 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 8.51 (dd, J = 15.6, 11.6 Hz, trans-
CH=CHCO2R, 1 H), 7.30–7.33 (m, C6H4, 4 H), 6.88–7.00 (m, C6H4,
4 H), 6.69 (t, J = 11.6 Hz, cis-CH=CHCO2R, 1 H), 6.18 (d, J = 15.6
Hz, trans-CH=CHCO2R, 1 H), 6.02 (d, J = 11.6 Hz, cis-
CH=CHCO2R, 1 H), 5.22 (s, OCH2, 2 H), 5.21 (s, OCH2, 2 H), 3.82
(s, OCH3, 3 H), 3.81 (s, OCH3, 3 H).
13C NMR (100 MHz, CDCl3): d = 165.76 and 164.94 (C=O), 159.72
and 159.57, 140.98, 138.96, 137.31, 137.10, 129.69, 129.63,
128.85, 113.90, 113.70, and 113.47 (CH= and C6H4), 66.34 and
66.29 (OCH2), 55.23 (CH3).
Polymerization; General Procedure
The monomer crystals were photoirradiated using a high-pressure
mercury lamp (Toshiba SHL-100-2, 100W, Pyrex filter) at a dis-
tance of 10 cm under atmospheric conditions at r.t. After irradiation,
the polymers were isolated by removal of the unreacted monomer
with CHCl3. For g-radiation polymerization, monomer crystals
were charged in a Pyrex tube, degassed, and then sealed. g-Radia-
tion was carried out with 60Co at r.t. The irradiation dose was 200
kGy. After irradiation, quantitative polymer formation was checked
by IR and NMR spectra.
UV (MeCN): lmax = 267 nm (e = 29700).
Poly[(Z,Z)-4-MeO]
Mp 199 °C.
IR (KBr): 974 (C=C), 1736 cm–1 (C=O).
Bis(4-methoxybenzyl) (E,Z)-Muconate [(E,Z)-4-MeO]
Colorless plates; mp 83.8–84.8 °C (CHCl3).
1H NMR (400 MHz, CDCl3): d = 7.10–7.14 (m, C6H4, 4 H), 6.74–
6.77 (m, C6H4, 4 H), 5.36 (br s, CH=CH, 2 H), 4.84 (q, OCH2, 4 H),
3.67 (s, 6 H, OCH3), 3.39 (br s, CH, 2 H).
13C NMR (100 MHz, CDCl3): d = 170.98 (C=O), 159.54, 130.20,
129.38, 127.70, and 113.86 (C6H4 and CH=), 66.61 (CH2), 55.14
(OCH3), 50.76 (CH).
IR (KBr): 1595 (C=C), 1711 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 8.43 (dd, J = 15.6, 11.6 Hz, trans-
CH=CHCO2R, 1 H), 7.20–7.35 (m, C6H4, 4 H), 6.87–6.91 (m, C6H4,
4 H), 6.62 (t, J = 11.6 Hz, cis-CH=CHCO2R, 1 H), 6.11 (d, J = 15.6
Hz, trans-CH=CHCO2R, 1 H), 5.96 (d, J = 11.6 Hz, cis-
CH=CHCO2R, 1 H), 5.16 (s, OCH2, 2 H), 5.14 (s, OCH2, 2 H), 3.81
(s, OCH3, 6 H).
13C NMR (100 MHz, CDCl3): d = 165.91, and 165.07 (C=O),
159.67 (C6H4), 140.78 and 138.82 (CH=), 130.28, 130.19, 128.97,
127.97, 127.75, and 124.54 (C6H4), 114.00 and 113.96 (CH=),
63.34 and 66.26 (CH2), 55.30 (CH3).
Poly[(Z,Z)-4-EtO]
Colorless plates; mp 187 °C.
IR (KBr): 974 (C=C), 1735 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 7.09–7.12 (m, C6H4, 4 H), 6.72–
6.75 (m, C6H4, 4 H), 5.40 (s, CH=, 2 H), 4.82 (q, 4 H, CH2), 3.88 (q,
4 H, CH2CH3), 3.43 (s, 2 H, CH), 1.32 (t, 6 H, CH2CH3);
UV (MeCN): lmax = 266 nm (e = 27100).
13C NMR (100 MHz, CDCl3): d = 170.87 (C=O), 158.88, 130.16,
129.31, 127.46, and 114.30 (C6H4 and CH=), 66.62 (CH2), 63.24
(CH2CH3), 50.85 (CH), 14.75 (CH2CH3).
Bis(4-ethoxybenzyl) (E,Z)-Muconate [(E,Z)-4-EtO]
Colorless prisms; mp 78.5–79.1 °C (CHCl3).
IR (KBr): 1600 (C=C), 1715 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 8.43 (dd, J = 15.6, 11.6 Hz, trans-
CH=CHCO2R, 1 H), 7.29–7.33 (m, C6H4, 4 H), 6.86–6.88 (m, C6H4,
4 H), 6.62 (t, J = 11.6 Hz, cis-CH=CHCO2R, 1 H), 6.13 (d, J = 15.6
Hz, trans-CH=CHCO2R, 1 H), 5.97 (d, J = 11.6 Hz, cis-
CH=CHCO2R, 1 H), 5.15 (s, OCH2, 2 H), 5.14 (s, OCH2, 2 H),
4.00–4.06 (m, CH2CH3, 4 H), 1.39–1.42 (m, CH2CH3, 6 H).
13C NMR (100 MHz, CDCl3): d = 165.93 and 165.09 (C=O), 159.11
and 159.05 (C6H4), 140.75 and 138.82 (CH=), 130.24, 130.15,
128.97, 127.80, 127.59, 124.56, 114.54, and 114.51 (C6H4 and
CH=), 66.38 and 66.29 (OCH2), 63.48 (CH2CH3), 14.81 (CH2CH3).
Poly[(Z,Z)-4-BuO]
Colorless plates.
IR (KBr): 975 (C=C), 1736 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 7.08–7.12 (m, C6H4, 4 H), 6.74–
6.77 (m, C6H4, 4 H), 5.59 (br s, CH=CH, 2 H), 4.73 (q, OCH2, 4 H),
3.82 (s, 4 H, CH2CH2CH2CH3), 3.31 (br s, CH, 2 H), 1.67–1.74 (m,
4 H, CH2CH2CH2CH3), 1.38–1.48 (m, 4 H, CH2CH2CH2CH3), 0.99
(t, 6 H, CH2CH2CH2CH3).
13C NMR (100 MHz, CDCl3): d = 170.28 (C=O), 159.19, 130.21,
129.74, 127.05, and 114.40 (C6H4 and CH=), 67.54 and 66.73
UV (MeCN): lmax = 266 nm (e = 29800).
(OCH2
and
CH2CH2CH2CH3),
52.27
(CH),
31.27
13.85
(CH2CH2CH2CH3),
(CH2CH2CH2CH3).
19.21 (CH2CH2CH2CH3),
Bis(4-butoxybenzyl) (E,Z)-Muconate [(E,Z)-4-BuO]
Colorless plates; mp 78.5–79.1 °C (CHCl3).
IR (KBr): 1598 (C=C), 1715 cm–1 (C=O).
Poly[(E,E)-3-MeO]
1H NMR (400 MHz, CDCl3): d = 8.43 (dd, J = 15.6, 11.6 Hz, trans-
CH=CHCO2R, 1 H), 7.29–7.33 (m, C6H4, 4 H), 6.87–6.89 (m, C6H4,
4 H), 6.62 (t, J = 11.6 Hz, cis-CH=CHCO2R, 1 H), 6.11 (d, J = 15.6
Hz, trans-CH=CHCO2R, 1 H), 5.97 (d, J = 11.6 Hz, cis-
CH=CHCO2R, 1 H), 5.15 (s, OCH2, 2 H), 5.13 (s, OCH2, 2 H),
3.93–3.98 (m, 4 H, CH2CH2CH2CH3), 1.72–1.80 (m, 4 H,
CH2CH2CH2CH3), 1.43–1.54 (m, 4 H, CH2CH2CH2CH3), 0.97 (t,
6H, CH2CH2CH2CH3).
Mp 193 °C.
IR (KBr): 984 (C=C), 1733 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 7.13–7.15 (m, C6H4, 2 H), 6.75–
6.80 (m, C6H4, 6 H), 5.59 (br s, CH=CH, 2 H), 4.81 (q, OCH2, 4 H),
3.69 (s, 6 H, OCH3), 3.35 (br s, CH, 2 H).
13C NMR (100 MHz, CDCl3): d = 170.22 (C=O), 159.61, 136.80,
129.71, 129.59, 120.46, 113.81, and 113.73 (C6H4 and CH=), 66.72
(CH2), 55.11 (OCH3), 50.77 (CH).
Synthesis 2005, No. 9, 1479–1490 © Thieme Stuttgart · New York

PAPER
Solid-State Polymerization of Substituted Benzyl Muconates
1489
Poly[(E,E)-4-MeO]
Colorless plates; mp 195 °C.
IR (KBr): 974 (C=C), 1735 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 7.10–7.14 (m, C6H4, 4 H), 6.74–
6.77 (m, C6H4, 4 H), 5.36 (br s, CH=CH, 2 H), 4.84 (q, OCH2, 4 H),
3.67 (s, 6 H, OCH3), 3.39 (br s, CH, 2 H).
13C NMR (100 MHz, CDCl3): d = 170.98 (C=O), 159.54, 130.20,
129.38, 127.72, and 113.86 (C6H4 and CH=), 66.61 (CH2), 55.14
(OCH3), 50.76 (CH).
(5) (a) Okamoto, Y.; Nakano, T. Chem. Rev. 1994, 94, 349.
(b) Nakano, T.; Shikisai, Y.; Okamoto, Y. Polym. J. 1996,
28, 51. (c) Hoshikawa, N.; Hotta, Y.; Okamoto, Y. J. Am.
Chem. Soc. 2003, 125, 12380.
(6) Porter, N. A.; Allen, T. R.; Breyer, R. A. J. Am. Chem. Soc.
1992, 114, 7676.
(7) (a) Matsumoto, A.; Odani, T. Macromol. Rapid Commun.
2001, 22, 1195. (b) Matsumoto, A. Polym. J. 2003, 35, 93.
(c) Matsumoto, A. Top. Curr. Chem. 2005, 254, 263.
(8) Matsumoto, A.; Tashiro, K.; Miyata, M.; Tsubouchi, T.;
Tanaka, T.; Odani, T.; Nagahama, S.; Tanaka, T.; Inoue, K.;
Saragai, S.; Nkamoto, S. Angew. Chem. Int. Ed. 2002, 41,
2502.
Poly[(E,E)-4-EtO]
Colorless plates; mp 181 °C.
IR (KBr): 973 (C=C), 1735 cm–1 (C=O).
1H NMR (400 MHz, CDCl3): d = 7.07–7.11 (m, C6H4, 4 H), 6.71–
6.74 (m, C6H4, 4 H), 5.39 (br s, CH=, 2 H), 4.82 (s, OCH2, 4 H), 3.88
(t, 4 H, CH2CH3), 3.42 (br s, CH, 2 H), 1.32 (t, 6 H, CH2CH3).
13C NMR (100 MHz, CDCl3): d = 170.89 (C=O), 158.88, 130.18,
129.80, 127.50, and 114.32 (C6H4 and CH=), 66.63 (CH2), 63.26
(CH2CH3), 50.85 (CH), 14.75 (CH2CH3).
(9) Matsumoto, A.; Odani, T.; Chikada, M.; Sada, K.; Miyata,
M. J. Am. Chem. Soc. 1999, 121, 11122.
(10) Matsumoto, A.; Nagahama, S.; Odani, T. J. Am. Chem. Soc.
2000, 122, 9109.
(11) Matsumoto, A.; Tanaka, T.; Tsubouchi, T.; Tashiro, K.;
Saragai, S.; Nakamoto, S. J. Am. Chem. Soc. 2002, 124,
8891.
(12) Nagahama, S.; Inoue, K.; Sada, K.; Miyata, M.; Matsumoto,
A. Cryst. Growth Des. 2003, 3, 247.
(13) Tieke, B. Adv. Polym. Sci. 1985, 71, 79.
(14) Tashiro, K.; Zadorin, A. N.; Saragai, S.; Kamae, T.;
Matsumoto, A.; Yokoi, K.; Aoki, S. Macromolecules 1999,
32, 7946.
(15) Tanaka, T.; Matsumoto, A. J. Am. Chem. Soc. 2002, 124,
9676.
Poly(EMU) (meso-Diisotactic-trans-2,5-polymer)
Colorless needles.
1H NMR (400 MHz, CDCl3): d = 5.56 (br s, CH=CH, 2 H), 4.02 (q,
CH2, 4 H), 3.27 (br s, CH, 2 H), 1.19 (t, CH3, 6 H).
13C NMR (100 MHz, CDCl3): d = 170.48 (C=O), 129.59 (CH=),
60.89 (CH2), 52.04 (CH), 14.01 (CH3).
(16) Nagahama, S.; Tanaka, T.; Matsumoto, A. Angew. Chem.
Int. Ed. 2004, 43, 3811.
(17) Elvidge, J. A.; Linstead, R. P.; Sims, P.; Orkin, B. A. J.
Chem. Soc. 1950, 2235.
(18) Hayashi, O.; Katagiri, M.; Rothberg, S. J. Am. Chem. Soc.
1955, 77, 5450.
X-ray Crystallography
Single crystal X-ray data were collected on a Rigaku R-AXIS RAP-
ID Imaging Plate diffractometer using Mo-Ka radiation monochro-
mated by graphite. The structures were solved by a direct method
with the program SIR92 and refined using full-matrix least-squares
procedures. All calculations were performed using the Crystal-
Structure crystallographic software package from the Molecular
Structure Corporation.
(19) Draths, K. M.; Frost, J. W. J. Am. Chem. Soc. 1990, 112,
9630.
(20) Odani, T.; Matsumoto, A.; Sada, K.; Miyata, M. Chem.
Commun. 2001, 2004.
(21) Matsumoto, A.; Yokoi, K.; Aoki, S.; Tashiro, K.; Kamae, T.;
Kobayashi, M. Macromolecules 1998, 31, 2129.
(22) Nishio, M.; Hirota, M.; Umezawa, Y. The CH/p Interaction:
Evidence, Nature, and Consequences; Wiley: New York,
1998.
(23) Sada, K.; Inoue, K.; Tanaka, T.; Tanaka, A.; Epergyes, A.;
Nagahama, S.; Matsumoto, A.; Miyata, M. J. Am. Chem.
Soc. 2004, 126, 1764.
(24) (a) Xiao, J.; Yang, M.; Lauher, J. W.; Fowler, F. W. Angew.
Chem. Int. Ed. 2000, 39, 2132. (b) Hoang, T.; Lauher, J. W.;
Fowler, F. W. J. Am. Chem. Soc. 2002, 124, 10656.
(c) Nomura, S.; Itoh, T.; Nakasho, H.; Uno, T.; Kubo, M.;
Sada, K.; Inoue, K.; Miyata, M. J. Am. Chem. Soc. 2004,
126, 2035.
(25) (a) Yoshioka, M.; Matsumoto, A.; Otsu, T.; Ando, I.
Polymer 1991, 32, 2741. (b) Yoshioka, M.; Matsumoto, A.;
Otsu, T. Polym. J. 1991, 23, 1191. (c) Matsumoto, A.; Otsu,
T. Macromol. Symp. 1995, 98, 139.
References
(1) (a) Odian, G. Principles of Polymerization, 4th ed.; Wiley:
New York, 2004. (b) Pino, P.; Suter, U. W. Polymer 1976,
17, 977. (c) Farina, M. Top. Stereochem. 1987, 17, 1.
(d) Coates, G. W. Chem. Rev. 2000, 100, 1223.
(2) (a) Curran, D. P.; Porter, N. A.; Giese, B. Stereochemistry of
Radical Reactions; VCH: Weinheim, 1996. (b) Radicals in
Organic Synthesis, Vol. 1 & 2; Renaud, P.; Sibi, M. P., Eds.;
Wiley-VCH: Weinheim, 2001. (c) Matsumoto, A. In
Handbook of Radical Polymerization; Matyjaszewski, K.;
Davis, T. P., Eds.; Wiley: New York, 2002, 691.
(d) Matsumoto, A.; Giese, B. Macromolecules 1996, 29,
3758. (e) Spichty, M.; Giese, B.; Matsumoto, A.; Fischer,
H.; Gescheidt, G. Macromolecules 2001, 34, 723.
(3) (a) Yamada, K.; Nakano, T.; Okamoto, Y. Macromolecules
1998, 31, 7598. (b) Matsumoto, A.; Nakamura, S. J. Appl.
Polym. Sci. 1999, 74, 290. (c) Isobe, Y.; Fujioka, D.;
Habaue, S.; Okamoto, Y. J. Am. Chem. Soc. 2001, 123,
7180. (d) Ray, B.; Isobe, Y.; Morioka, K.; Habaue, S.;
Okamoto, Y.; Kamigaito, M.; Sawamoto, M.
Macromolecules 2003, 36, 543. (e) Lutz, J. F.; Neugebauer,
D.; Matyjaszewski, K. J. Am. Chem. Soc. 2003, 125, 6986.
(4) (a) Feldman, K. S.; Porter, N. A.; Allen, J. R. Templated
Organic Synthesis; Diederich, F.; Stang, P. J., Eds.; Wiley-
VCH: Weinheim, 2000, 219. (b) Serizawa, T.; Hamada, K.;
Akashi, M. Nature 2004, 429, 52.
(26) Ishihara, N.; Seimiya, M.; Kuramoto, M.; Uoi, M.
Macromolecules 1986, 19, 2465.
(27) Ewen, J. A.; Jones, R. L.; Razavi, A.; Ferrara, J. D. J. Am.
Chem. Soc. 1988, 110, 6255.
(28) (a) Kitayama, T.; Masuda, E.; Yamaguchi, M.; Nishiura, T.;
Hatada, K. Polym. J. 1992, 24, 817. (b) Yasuda, H.;
Yamamoto, H.; Yamashita, M.; Yokota, K.; Nakamura, A.;
Miyake, S.; Kai, Y.; Kanehisa, N. Macromolecules 1993, 26,
7134.
Synthesis 2005, No. 9, 1479–1490 © Thieme Stuttgart · New York

1490
A. Matsumoto et al.
PAPER
(29) (a) Ute, K.; Asada, T.; Nabeshima, Y.; Hatada, K. Polym.
Bull. 1993, 30, 171. (b) Ute, K.; Tarao, T.; Honjo, S.;
Ohnuma, H.; Hatada, K.; Kitayama, T. Polym. J. 1999, 31,
177.
(30) Takasu, A.; Ishii, M.; Inai, Y.; Hirabayashi, T.; Inomata, K.
Macromolecules 2003, 36, 7055.
(31) (a) Natta, G.; Farina, M.; Donati, M. Makromol. Chem.
1961, 43, 251. (b) Donati, M.; Perego, G.; Farina, M.
Makromol. Chem. 1965, 85, 301.
Synthesis 2005, No. 9, 1479–1490 © Thieme Stuttgart · New York