Novel palladium(0)-catalyzed polyaddition of bifunctional vinyloxiranes with 1,3-diketones. Synthesis of new polymers bearing an allyl alcohol moiety via π-allylpalladium intermediates

Article abstract of DOI:10.1021/ma011900i

Palladium(0)-catalyzed polyaddition of bifunctional vinyloxiranes [1,4-bis(2-vinylepoxyethyl)benzene (6a) and 1,4-bis(1-methyl-2-vinylepoxyethyl)benzene (6b)] with 1,3-diketones [acetylacetone (2) and 1,3-indandione (8)] as carbon nucleophiles afforded new polymers having an allyl alcohol moiety in the main chain and ketone groups in the side groups. The molecular weights of polymers obtained from 6b were higher than those of polymers from 6a. It was suggested that the cause of formation of lower molecular weight polymers from 6a is the β-hydrogen elimination of the π-allylpalladium intermediate generated by oxidative addition of Pd(0) to 6a. The Pd(0)-catalyzed polyaddition of 6b and 2 gave the corresponding polymer 7b (M_n 9800) when Pd₂(dba)₃·CHCl₃/dppf (dba, dibenzylideneacetone; dppf, 1,2-bis(diphenylphosphino)ferrocene) was used as a catalyst. By use of Pd(PPh₃)₄, the polyaddition of 6b and 8 afforded the desired polymer 9b with high molecular weight (M_n 67 600). The stereochemistries of all of the obtained polymers were confirmed as being in the E-configuration by the coupling constant of the vinyl proton (-C(OH)CH=CHCH₂-); the J values were in the range 14.5-15.1. The Z-isomers were observed neither in the ¹³C NMR spectra nor in the ¹H NMR spectra.

Full text of DOI:10.1021/ma011900i

2898
Macromolecules 2002, 35, 2898-2902
Novel Palladium(0)-Catalyzed Polyaddition of Bifunctional
Vinyloxiranes with 1,3-Diketones. Synthesis of New Polymers Bearing
an Allyl Alcohol Moiety via π-Allylpalladium Intermediates
Tosh io Koizu m i,*† J u n Sa k a m oto,† Ya su h ik o Gon d o,† a n d Ta k esh i En d o‡
Department of Applied Chemistry, The National Defense Academy, Hashirimizu,
Yokosuka 239-8686, J apan; and Department of Polymer Science and Engineering, Yamagata
University, Yonezawa 992-8510, J apan
Received November 1, 2001; Revised Manuscript Received J anuary 23, 2002
ABSTRACT: Palladium(0)-catalyzed polyaddition of bifunctional vinyloxiranes [1,4-bis(2-vinylepoxyethyl)-
benzene (6a ) and 1,4-bis(1-methyl-2-vinylepoxyethyl)benzene (6b)] with 1,3-diketones [acetylacetone (2)
and 1,3-indandione (8)] as carbon nucleophiles afforded new polymers having an allyl alcohol moiety in
the main chain and ketone groups in the side groups. The molecular weights of polymers obtained from
6b were higher than those of polymers from 6a . It was suggested that the cause of formation of lower
molecular weight polymers from 6a is the â-hydrogen elimination of the π-allylpalladium intermediate
generated by oxidative addition of Pd(0) to 6a . The Pd(0)-catalyzed polyaddition of 6b and 2 gave the
corresponding polymer 7b (Mn 9800) when Pd2(dba)3‚CHCl3/dppf (dba, dibenzylideneacetone; dppf, 1,2-
bis(diphenylphosphino)ferrocene) was used as a catalyst. By use of Pd(PPh3)4, the polyaddition of 6b and
8 afforded the desired polymer 9b with high molecular weight (Mn 67 600). The stereochemistries of all
of the obtained polymers were confirmed as being in the E-configuration by the coupling constant of the
vinyl proton (-C(OH)CHdCHCH2-); the J values were in the range 14.5-15.1. The Z-isomers were
observed neither in the 13C NMR spectra nor in the 1H NMR spectra.
Sch em e 1
In tr od u ction
Palladium-catalyzed allylic alkylation reaction using
soft carbon nucleophiles is a very versatile carbon-
carbon bond formation reaction in organic synthesis. A
great variety of active methylene compounds can be
used.1 The substrates for this reaction commonly are
allylic compounds such as allylic acetates and carbon-
ates. The ring-opening reaction of vinyloxirane deriva-
tives by organometallics has provided a valuable ap-
proach to allylic alcohols, which are useful for synthesis
of functionalized compounds.2 It is also known that a
Pd(0)-catalyzed reaction of vinyloxiranes with pronu-
cleophiles (NuH) such as carbon nucleophiles and
amines gives synthetically useful (E)-allylic alcohols via
π-allylpalladium intermediates.3 In this reaction, the
nucleophilic attack takes place selectively under neutral
conditions at the terminal carbon (Scheme 1).
This Pd(0)-catalyzed reaction prompted us to explore
the synthesis of new functional polymers. Although the
palladium-catalyzed allylic alkylation reaction is widely
used in organic synthesis, there are only a few reports
of polymer synthesis via π-allylpalladium intermedi-
ates.4 Polymers bearing hydroxy groups are important
in coatings, adhesives, and polymeric reagents.5 How-
ever, it is very difficult to synthesize a variety of
polymers having hydroxy and other functional groups.
There is a report of the preparation of such polymers
reported by Nomura et al.6
bond cleavage of the oxirane ring.7 This is the first
example of palladium-catalyzed polyaddition of bifunc-
tional vinyloxirane with carbon nucleophiles. In this
paper, we wish to report in detail the palladium-
catalyzed polyaddition of bifunctional vinyloxiranes [6a
and 1,4-bis(1-methyl-2-vinylepoxyethyl)benzene (6b)]
and 1,3-diketones as carbon nucleophiles under various
conditions.
Exp er im en ta l Section
Ma ter ia ls. Extra-pure grade reagents were used without
further purification, unless otherwise stated. Tetrahydrofuran
(THF) used as a solvent for polymerization was purified by
distillation according to the usual method.
Mea su r em en t. IR spectra were recorded on a J ASCO FT/
IR-3 spectrometer. 1H NMR spectra and 13C NMR spectra were
recorded on a Bruker-DMX 500 with CDCl3, acetone-d6, or
DMSO-d6 as solvent and Me4Si as an internal standard. Gel
permeation chromatograms were taken with a Shimadzu
HPLC LC-6A system equipped with two columns (Shim-pack
GPC-802 and GPC-804), and tetrahydrofuran (THF) was used
as an eluent at 45 °C.
P r epar ation of 1,4-Bis(2-vin ylepoxyeth yl)ben zen e (6a).
A mixture of allyl bromide (44.8 g, 0.370 mol) and dimethyl
sulfide (28.8 g, 0.463 mol) in water (25 mL) was stirred at room
temperature overnight. Unreacted dimethyl sulfide was re-
moved at reduced pressure. Isopropyl alcohol (80 mL) and
Recently, we have reported as a preliminary com-
munication that the palladium(0)-catalyzed polyaddition
of a bifunctional vinyloxirane, 1,4-bis(2-vinylepoxyeth-
yl)benzene (6a ), and carbon nucleophiles can lead to the
formation of new polymers having an allyl alcohol
moiety in the main chain accompanying carbon-oxygen
† The National Defense Academy.
‡ Yamagata University.
10.1021/ma011900i CCC: $22.00 © 2002 American Chemical Society
Published on Web 03/12/2002

Macromolecules, Vol. 35, No. 8, 2002
Novel Pd(0)-Catalyzed Polyaddition 2899
Ta ble 1. P d (0)-Ca ta lyzed P olya d d ition of 6a w ith
Acetyla ceton e (2)
terephthalaldehyde (20.0 g, 0.149 mol) were added to the
reaction mixture at room temperature, and subsequently,
sodium hydroxide (16.9 g, 0.423 mol) in water (30 mL) was
added dropwise at room temperature with vigorous stirring.
After this mixture was stirred for 6 h, the resulting dimethyl
sulfide was removed under reduced pressure and the solution
was extracted with ether three times. The organic layer was
washed with water and saturated sodium chloride successively
and dried over anhydrous magnesium sulfate. The ether
solution was distilled in vacuo to obtain 6a (12.0 g, 38%): bp
120-122 °C/0.4 mmHg (lit.8 140 °C/0.1 mmHg); IR (neat) 3079,
temp time yield
c
c
run
Pd(0)a
(°C)
(h)
(%)b
Mn
Mw/Mn
1
2
3
4
5
6
7
8
9
Pd(PPh3)4 (5)
Pd(PPh3)4 (5)
Pd(PPh3)4 (5)
Pd(PPh3)4 (5)
Pd(PPh3)4 (1)
Pd(PPh3)4 (1)
Pd2(dba)3/4dppe (5) rt
Pd2(dba)3/4dppp (5) rt
Pd2(dba)3/4dppb (5) rt
0
6
6
24
6
100 3400
98 3600
100 3600
100 3300
0
93 4700
100 3400
100 3700
79 3500
87 3800
2.73
2.04
2.46
2.17
2989, 1864, 1641, 1517, 1444, 1184, 987, 933, 879, 827 cm-1
;
rtd
rt
1H NMR (CDCl3) δ 3.33-3.35 (-CdCCH- (trans), m, 1.2H),
3.65-3.68 (-CdCCH- (cis), m, 0.8H), 3.77 (-CHAr- (trans),
d, J ) 1.3 Hz, 1.2H), 4.23 (-CHAr- (cis), d, J ) 4.2 Hz, 0.8H),
5.28-5.74 (CH2dCH-, m, 6H), 7.26-7.33 (ArH, m, 4H).
P r ep a r a tion of 1,4-Bis(1-m eth yl-2-vin ylep oxyeth yl)-
ben zen e (6b). A mixture of allyl bromide (96.8 g, 0.800 mol)
and tetrahydrothiophene (72.3 g, 0.800 mol) in water (30 mL)
was stirred at room temperature overnight. Isopropyl alcohol
(60 mL) and 1,4-diacetylbenzene (25.0 g, 0.154 mol) were added
to the reaction mixture at room temperature, and subse-
quently, sodium hydroxide (32.0 g, 0.800 mol) in water (30 mL)
was added dropwise at 0 °C with vigorous stirring. After being
stirred overnight at room temperature, the reaction mixture
was extracted with ether three times. The organic layer was
washed with water and saturated sodium chloride successively
and dried over anhydrous magnesium sulfate. The ether
solution was evaporated to dryness. The crude product was
purified by column chromatography on silica gel (hexanes-
ethyl acetate, 4:1) to afford the title vinyloxirane 6b. Further
purification was made by distillation (19.9 g, 55%): bp 112-
114 °C/0.2 mmHg; IR (neat) 3079, 2989, 1864, 1641, 1517,
reflux
rt
rt
6
24
24
24
24
24
2.31
2.49
2.37
3.03
3.43
10 Pd2(dba)3/4dppf (5) rt
a
b
Numbers in parentheses: [Pd/6a ] × 100. Insoluble in tolu-
d
ene. c Estimated by GPC (based on PSt). Room temperature.
Sch em e 2
1
1444, 1184, 987, 933, 879, 827 cm-1; H NMR (acetone-d6) δ
1.63-1.65 (CH3, m, 6H), 3.27-3.62 (-CdCCH-, m, 2H), 5.10-
5.93 (CH2dCH-, m, 6H), 7.37 (ArH, s, 4H); 13C NMR (acetone-
d6) δ 17.9, 24.8, 64.3, 67.3, 121.1, 121.2, 125.7, 126.0, 127.3,
127.5, 134.2, 135.0. Anal. Calcd for C16H18O2: C, 79.31; H, 7.49.
Found: C, 79.13; H, 7.53.
NMR (acetone-d6) δ 26.4, 28.8, 33.0, 69.6, 72.7, 120.0, 124.4,
141.9, 145.5, 205.4.
P d (0)-Ca ta lyzed Rea ction of 2-P h en yl-3-vin yloxir a n e
(1) a n d Acetyla ceton e (2). To a solution of 2 (0.100 g, 1.0
mmol) and Pd(PPh3)4 (0.116 g, 0.10 mmol) in THF (5 mL) was
added a solution of 18 (0.292 g, 2.0 mmol) in THF (1 mL). After
being stirred for 3 h at room temperature under argon, the
reaction mixture was evapoporated to dryness. The residue
was subjected to column chromatography on silica gel (hex-
anes-ethyl acetate, 1:1) to give the desired 2:1 adduct 3 (0.370
g, 94%): IR (neat) 3417, 3030, 2921, 1693, 1450, 1357, 1172,
971, 755 cm-1; 1H NMR (acetone-d6) δ 2.00 (CH3, s, 6H), 2.55-
2.64 (-CH2-, m, 4H), 4.51 (OH, s, 2H), 5.05 (CH, s, 2H), 5.44-
5.50 (-CHdCHCH2-, m, 2H), 5.63 (-CHCHdCH-, dd, J )
15.1 and 6.1 Hz, 2H), 7.15-7.27 (ArH, m, 10H); 13C NMR
(acetone-d6) δ 26.9, 33.9, 70.1, 73.9, 123.9, 127.1, 127.8, 128.6,
138.3, 144.5, 206.1; HRMS: calcd for C25H28O4, 392.1988;
found, 392.1991.
9a , a pale purple solid: IR (KBr) 34276, 3022, 2908, 1703,
1244, 975 cm-1; 1H NMR (DMSO-d6) δ 2.44-2.48 (-CH2-, m,
4H), 4.73 (OH, s, 2H), 5.21-5.30 (-CHdCHCH2- and -CH-,
m, 3H), 5.48 (-CHCHdCH-, dd, J ) 15.0 and 5.7 Hz, 2H),
6.67 (ArH, s, 4H), 7.86-7.94 (ArH, m, 2H), 8.00 (ArH, s, 2H);
13C NMR (DMSO-d6) δ 37.2, 58.5, 72.5, 122.3, 123.2, 125.9,
136.8, 138.7, 142.2, 142.7, 203.5.
9b, a gray solid: IR (KBr) 3427, 1974, 2925, 1703, 1357,
1242, 976 cm-1; 1H NMR (DMSO -d6) δ 1.14 (CH3, s, 6H), 2.45-
2.51 (-CH2-, m, 4H), 4.99 (OH, s, 2H), 5.11-5.14 (-CHd
CHCH2-, m, 2H), 5.58 (-CCHdCH-, d, J ) 15.1 Hz, 2H),
6.75 (ArH, s, 4H), 7.92 (ArH, s, 2H), 8.01 (ArH, s, 2H); 13C
NMR (DMSO-d6) δ 29.9, 37.1, 58.8, 72.6, 119.7, 123.1, 124.6,
136.8, 142.3, 142.9, 145.6, 203.6.
P d (0)-Ca ta lyzed P olya d d ition of Bifu n ction a l Vin yl-
oxir a n es 6 w ith Acetyla ceton e (2): A Typ ica l P r oced u r e.
To a solution of 2 (0.201 g, 2.0 mmol) and Pd(PPh3)4 (0.023 g,
0.02 mmol) in THF (4 mL), a solution of 6a (0.428 g, 2.0 mmol)
in THF (2 mL) was added. The mixture was stirred at room
temperature for 24 h under argon and poured into toluene (100
mL) to precipitate polymer (Table 1, run 6). The resulting
polymer 7a was filtered off, washed with toluene, and dried
in vacuo (0.582 g, 93%) giving a pale yellow solid: IR (KBr)
3400, 3010, 2919, 2862, 1693, 1421, 1358, 1173, 1086, 972
cm-1; 1H NMR (acetone-d6) δ 2.01 (CH3, s, 6H), 2.59 (-CH2-,
s, 4H), 4.51 (OH, s, 2H), 5.02 (-CH-, s, 2H), 5.42-5.48 (-CHd
CHCH2-, m, 2H), 5.60 (-CHCHdCH-, dd, J ) 14.5 and 5.4
Hz, 2H), 7.21 (s, 4H); 13C NMR (acetone-d6) δ 27.0, 33.88, 70.1,
73.8, 123.8, 126.1, 138.2, 143.1, 206.0.
Resu lts a n d Discu ssion
1. P d (0)-Ca ta lyzed P olya d d ition of Vin yloxir a n e
6a w it h Acet yla cet on e (2). It is known that the
Pd(0)-catalyzed addition of vinyloxiranes with active
methylene compounds affords 1:1 adducts in good yields
(Scheme 1).3 Although the adducts still have one active
hydrogen, the formation of 2:1 adducts has not been
reported yet. Hence, the Pd(0)-catalyzed addition of
2-phenyl-3-vinyloxirane (1) with acetylacetone (2) (pKa
9)9 was examined as a model reaction. The Pd(0)-
catalyzed addition using 2 equiv of 1 to 2 was carried
out at room temperature for 3 h in the presence of
Pd(PPh3)4 (5 mol % for 1). The desired 2:1 adduct (3)
was isolated in 94% yield by flash column chromatog-
raphy (Scheme 2). However, when dimethyl malonate
(pKa 13)9 was employed as a carbon nucleophile under
the same conditions, the corresponding 2:1 product was
7b, a pale yellow-brown solid: IR (KBr) 3435, 2976, 2927,
1693, 1360, 1171, 1080, 974 cm-1; 1H NMR (acetone-d6) δ 1.54
(CH3, s, 6H), 2.09 (CH3C(dO), s, 6H), 2.66 (-CH2-, d, J ) 7.1
Hz, 4H), 4.39 (OH, s, 2H), 5.48-5.54 (-CHdCHCH2-, m, 2H),
5.83 (-CCHdCH-, d, J ) 15.1 Hz, 2H), 7.39 (ArH, s, 4H);13C

2900 Koizumi et al.
Macromolecules, Vol. 35, No. 8, 2002
Sch em e 3
not isolated (Scheme 2). In this case, 1:1 adduct (4) was
obtained in 45% yield. These results suggest that active
methylene compounds with lower pKa values are re-
quired to obtain 2:1 adducts in high yields. A plausible
reaction mechanism of the formation of 3 is shown in
Scheme 3. The oxidative addition of Pd(0) to vinylox-
irane 1 affords π-allylpalladium intermediate A, which
abstracts the methylene proton of 2 to generate car-
banion 2-. Nucleophilic attack of 2- on π-allylpalladium
intermediate B gives the corresponding 1:1 adduct (5),
which reacts with 1 to yield 2:1 adduct 3. Although the
pKa value of 5 is higher than that of 2, 5 seems to have
a sufficient lower pKa value for proton abstraction by
intermediate A. In the case of reaction of 1 and dimethyl
malonate, however, the expected 2:1 adduct was not
obtained by reaction of 1:1 adduct 4 with 1. Adduct 4
has a higher pKa value than that of dimethyl malonate.
It can therefore be presumed that π-allylpalladium
intermediate A cannot abstract the active hydrogen of
adduct 4 to produce the corresponding 2:1 adduct. Thus,
acetylacetone as a carbon nucleophile is a good candi-
date for the polyaddition of bifunctional vinyloxirane,
1,4-bis(2-vinylepoxyethyl)benzene (6a ).
Bifunctional vinyloxirane 6a was synthesized by the
phase-transfer reaction of an allyldimethylsulfonium
salt with terephthalaldehyde according to the method
reported in our previous paper.8 The Pd(0)-catalyzed
polyaddition of 6a with 2 was carried out in THF under
various conditions. The formed polymers were isolated
by pouring the reaction mixtures into toluene. The
results are summarized in Table 1. In the polyaddition
using 5 mol % of Pd(PPh3)4 relative to 6a , the desired
polymers (7a ) were obtained quantitatively (runs 1-4).
The reaction temperature and the time did not affect
the yield and average molecular weight (Mn) of 7a .
These results indicate that the polyaddition of 6a and
2 is fast under these conditions. The decrease of amount
of Pd(PPh3)4 required longer reaction time. The poly-
addition at room temperature for 6 h did not afford 7a
when 1 mol % of Pd(PPh3)4 was used (run 5), although
prolonged polymerization time (24 h) did (93%, Mn 4700)
(run 6).
F igu r e 1. 1H NMR spectra of 7a and 7b (acetone-d6, 500
MHz).
yield than those of the polymers obtained with dppe,
dppp, and dppf. These results indicate that the polyad-
dition of 6a with 2 did not depend on the kind of the
ligands employed. The polymers were soluble in acetone,
THF, and DMSO. The structure of the polymers was
confirmed by comparison with IR and NMR spectra of
model compound 3. All of the proton signals of 7a could
be assigned and were in good agreement with those of
3. The signals due to methylene and vinyl protons were
observed around 2.59, 5.42-5.48 (-CHdCHCH2-), and
5.60 (-CHdCHCH2-) ppm (Figure 1a). The observation
of these protons reveals that carbon-oxygen bond
cleavage of the oxirane ring occurred. Similarly, all of
the carbon signals of 7a could also be assigned and
agreed well with those of 3.7 The stereochemistries of 3
and 7a were confirmed as E-configuration by the
coupling constant of the vinyl proton d of 7a ; the J
values of 3 and 7a were 15.1 and 14.5 Hz, respectively.
The Z-isomers were observed neither in the 13C NMR
1
spectra nor in the H NMR spectra of 3 and 7a . These
results demonstrate that the selectivity is exclusive as
reported by Tsuji and Trost.3 The IR spectra of both 3
and 7a show the characteristic absorptions based on the
hydroxy and carbonyl groups around 3400 and 1690
cm-1, respectively. From the NMR and IR spectral data,
we confirmed that the Pd(0)-catalyzed polyaddition of
6a with 2 produced polymers having an allyl alcohol
moiety in the main chain and carbonyl groups in the
side groups.
Next, the effect of the ligands, 1,2-bis(diphenylphos-
phino)ethane (dppe), 1,2-bis(diphenylphosphino)propane
(dppp), 1,2-bis(diphenylphosphino)butane (dppb), and
1,2-bis(diphenylphosphino)ferrocene (dppf) on the poly-
addition was examined. The polyaddition of 6a and 2
was carried out in the presence of Pd2(dba)3‚CHCl3 (dba
) dibenzylideneacetone; 2.5 mol % for 6a ). All of the
ligands produced polymers with molecular weights in
the range 3400-3800 (runs 7-10), which were very
similar to the results using Pd(PPh3)4. The polyaddition
using dppb produced polymer 7a with somewhat lower
In the polyaddition of 6a and 2, the molecular weights
of the obtained polymers were not high. The main
reason seems to be the occurrence of â-hydrogen elimi-
nation as a termination. It is known that palladium-
catalyzed isomerization of vinyloxiranes in the absence
of nucleophiles gives â,γ-unsaturated ketones via â-
hydrogen elimination of intermediate C (Scheme 4).10
By the oxidative addition of Pd(0) to vinyloxirane 1,
A is generated, which functions as a base and abstracts
a proton of 2 in the presence of a pronucleophile

Macromolecules, Vol. 35, No. 8, 2002
Novel Pd(0)-Catalyzed Polyaddition 2901
Ta ble 3. P d (0)-Ca ta lyzed P olya d d ition of 6 w ith
1,3-In d a n d ion ea
Sch em e 4
yield (%)b
Mn
Mw/Mn
c
c
run oxirane
Pd(0)
1
2
3
4
6a
6a
6b
6b
Pd(PPh3)4
Pd2(dba)3/4dppe
Pd(PPh3)4
87
100
80
9200
7500
67 600
25 000
1.96
2.28
3.17
4.07
Sch em e 5
Pd2(dba)3/4dppe
95
a
b
Conditions: Pd/6 ) 0.05, room temperature, 24 h. Insoluble
in toluene. c Estimated by GPC (based on PSt).
perature and the time affected the average molecular
weight (Mn) of 7b, contrary to the polyaddition with 7a .
The Mn values of the obtained polymers increased from
3100 to 6300 with the temperature elevating from 0 °C
to reflux (runs 1, 2, and 4). Although the Mn of 7b
obtained by polymerization for 6 h was 4400, prolonged
reaction time (24 h) gave 7b with higher molecular
weight (Mn 6000) (runs 2 and 3). The molecular weights
of the obtained polymers (runs 3 and 4) were higher
than those of polymers 7a from 6a under the same
conditions (runs 3 and 4 in Table 1).
Ta ble 2. P d (0)-Ca ta lyzed P olya d d ition of 6b w ith
Acetyla ceton e (2)
The polyaddition of 6b and 2 was also carried out at
room temperature for 24 h in the presence of Pd2(dba)3‚
CHCl3 (2.5 mol % for 6b). Bidentate phosphine ligands
(dppe, dppp, dppb, and dppf) were employed (runs 5-8).
All of these ligands gave polymers with high Mn values
ranging from 7900 to 10000, compared with the Mn
values of polymers 7b obtained by polymerization using
Pd(PPh3)4. These results indicate that the bidentate
phosphine ligands employed are more effective than
PPh3 in the polyaddition of 6b and 2.
temp time yield
c
c
run
Pd(0)a
(°C)
(h)
(%)b
Mn
Mw/Mn
1
2
3
4
5
6
7
8
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)4
0
6
6
24
6
76
100
100
82
3100
4400
6000
6300
9400
7900
1.63
3.09
3.48
2.83
6.05
5.69
6.55
4.47
rtd
rt
reflux
Pd2(dba)3/4dppe rt
Pd2(dba)3/4dppp rt
Pd2(dba)3/4dppb rt
Pd2(dba)3/4dppf rt
24
24
24
24
92
92
75 10 000
87 9800
Pd/6b ) 0.05. Insoluble in toluene. c Estimated by GPC
(based on PSt). Room temperature.
a
b
Polymers 7b were soluble in methanol, acetone, THF,
and DMSO. The structure of the polymers was con-
d
1
firmed by IR and NMR spectra. The H NMR spectrum
(Scheme 3). Intermediate A has a â-hydrogen atom at
the benzylic position. The reaction of 1 using Pd(PPh3)4
(5 mol %) was also carried out at room temperature for
16 h in the absence of 2 in THF. Vinyloxirane 1
completely disappeared and the formation of a â,γ-
unsaturated ketone was confirmed by the 1H NMR
spectrum of the reaction mixture; the characteristic
signals of methylene protons of the ketone were ob-
served (3.24 ppm, doublet, J ) 7.5 Hz). As the polyad-
dition of 6a and 2 proceeds, the amount of the propa-
gating end groups having active hydrogen decreases.
Therefore, the â-hydrogen elimination of the end groups
bearing vinyloxirane moieties seems to take place at the
final stage as shown in Scheme 5. The clear signals of
such an unsaturated ketone group could not be detected
of 7b is illustrated in Figure 1b. All of the proton signals
of 7b could be assigned. The methylene and vinyl
protons were observed around 2.66, 5.48-5.54 (-CHd
CHCH2-), and 5.83 (-CHdCHCH2-) ppm. The signals
based on vinyloxirane 6b completely disappeared. The
stereochemistry of 7b as well as 7a was confirmed as
being in the E-configuration. The coupling constant of
the vinyl proton d of 7b was 15.1 Hz. The IR spectrum
of 7b exhibits the characteristic absorptions due to the
hydroxy and carbonyl groups at 3435 and 1693 cm-1
respectively.
,
Thus, we succeeded in obtaining polymers 7b with
higher molecular weights than those of polymers 7a as
expected.
3. P d (0)-Ca t a lyzed P olya d d it ion of Vin ylox-
ir a n es 6 w ith 1,3-In d a n d ion e 8. We found that the
polyaddition of 6 with 2 as an acyclic 1,3-diketone
afforded the desired polymers in good to excellent yields.
Third, we examined the polyaddition of 6 using 1,3-
indandione (8) as a cyclic 1,3-diketone. The results are
shown in Table 3. The polyaddition of 6a and 8 was
carried out using Pd(PPh3)4 to afford the expected
polymer (9a ) (Mn 9200) in 87% yield, whereas polymer
9a with somewhat lower Mn was obtained by polymer-
ization using Pd2(dba)3/dppe (runs 1 and 2). The polym-
erization of 6b and 8 gave polymers 9b with much
higher molecular weights. When Pd(PPh3)4 was used as
a catalyst, the Mn value of the obtained polymer was
1
in the H and 13C NMR spectra of 7a .
2. P d (0)-Ca ta lyzed P olya d d ition of Vin yloxir a n e
6b w ith 2. Second, the polyaddition of 1,4-bis(1-methyl-
2-vinylepoxyethyl)benzene (6b ) and 2 was examined.
The π-allylpalladium intermediate generated by oxida-
tive addition of Pd(0) to 6b does not possess â-hydrogen.
Consequently, the molecular weights of the polymers
obtained from 6b and 2 are expected to be higher than
those of polymers 7a . The polymerization of 6b and 2
was conducted in THF under various conditions. Table
2 shows the results. The polyaddition using Pd(PPh3)4
(5 mol % for 6b) afforded the expected polymers (7b) in
good to excellent yields (runs 1-4). The reaction tem-

2902 Koizumi et al.
Macromolecules, Vol. 35, No. 8, 2002
67 600 (run 3). Polymerization in the presence of
Pd2(dba)3/dppe also afforded the desired polymer (run
4) of which the Mn value was 25 000. In both the
polyaddition of 6a and 6b, the Mn values of 9a and 9b
were high when Pd(PPh3)4 was employed. These results
indicate that PPh3 as the ligand is more effective than
dppe, contrary to the polyaddition of 6b and 2. Polymers
9a and 9b were soluble in THF and DMSO. The
structure was determined by IR and NMR spectra
(Experimental Section). The stereochemistries of 9a and
9b were confirmed as being in the E-configuration by
the coupling constant of the vinyl proton; the J values
of 9a and 9b were 15.0 and 15.1 Hz, respectively. The
Z-isomers could not be detected in the NMR spectra.
tion of 6b and 8 afforded polymer 9b with high molec-
ular weight (Mn 67 600). The stereochemistries of all of
the polymers 7 and 9 were E-configuration. The Z-
isomers were not observed in the NMR spectra. The
spectral data of the obtained polymers demonstrated
that the selectivity was exclusive.
Refer en ces a n d Notes
(1) (a) Tsuji, J . Palladium Reagents and Catalysts, Innovations
in Organic Synthesis; J ohn Wiley: New York, 1995; p 290.
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(2) Marshall, J . A. Chem. Rev. 1989, 89, 1503.
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Con clu sion
In this work, we found that the Pd(0)-catalyzed
polyaddition of 6a and 6b with 1,3-diketones proceeded
successfully to give new polymers having an allyl alcohol
moiety in the main chain and could demonstrated the
first example of palladium-catalyzed polyaddition of
bifunctional vinyloxirane with carbon nucleophiles. It
is suggested that the cause of formation of lower
molecular weight polymers from 6a is the â-hydrogen
elimination of the π-allylpalladium intermediate gener-
ated by oxidative addition of Pd(0) to 6a . In both the
polyadditions using 1,3-diketones 2 and 8, the molecular
weights of polymers obtained from 6b were higher than
those of polymers from 6a . In particular, the polyaddi-
(8) Koizumi, T.; Sakamoto, J .; Moriya, O.; Urata, Y.; Yoshikawa,
N.; Endo, T. Macromolecules 1995, 5649.
(9) March. J . Advanced Organic Chemistry, 4th ed.; Wiley-
Interscience: New York, 1992; p 251.
(10) Suzuki, M.; Oda, Y.; Noyori, R. J . Am. Chem. Soc.. 1979, 101,
1623.
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