Quick access to diverse polymerizable molecules (a monomer library) by catalytic [2 + 2 + 2] cycloaddition reactions of functionalized alkynes

Article abstract of DOI:10.1021/ma902792a

The [2 + 2 + 2] cycloaddition reactions of 1,6-diynes and alkynes with a functional, group(s), such as epoxide, oxetane, ester, alcohol, phenol, amine, borate, styrene, and methacrylate, catalyzed by a dipimp/ CoCl ₂· 6H₂O/Zn reagent

Full text of DOI:10.1021/ma902792a

Macromolecules 2010, 43, 2213–2218 2213
DOI: 10.1021/ma902792a
Quick Access to Diverse Polymerizable Molecules (a Monomer Library) by
Catalytic [2 þ 2 þ 2] Cycloaddition Reactions of Functionalized Alkynes
Jun-ichi Watanabe,† Yu-ki Sugiyama,† Ayami Nomura,† Suzumi Azumatei,† Avijit Goswami,†
Naoko Saino,‡ and Sentaro Okamoto*,†
†Department of Material & Life Chemistry, Kanagawa University, 3-27-1 Rokkakubashi, Kanagawaku,
Yokohama 221-8686, Japan, and ‡New Products Development Division, Kanto Denka Kogyo Co., Ltd., 425
Kanai, Shibukawa, Gunma 377-0027, Japan
Received December 18, 2009; Revised Manuscript Received January 22, 2010
ABSTRACT: The [2 þ 2 þ 2] cycloaddition reactions of 1,6-diynes and alkynes with a functional group(s), such
as epoxide, oxetane, ester, alcohol, phenol, amine, borate, styrene, and methacrylate, catalyzed by a dipimp/
CoCl2 6H2O/Zn reagent [dipimp: 2-(2,6-diisopropylphenyl)-iminomethyl-pyridine] yielded a variety of polymeri-
3
zable molecules (monomers) having a 2,3-dihydro-1H-indene core structure. Similarly, the [2 þ 2 þ 2]
cycloaddition reactions of 1,6-diynes and nitriles with a functional group(s) catalyzed by a dppe/CoCl2 6H2O/
3
Zn reagent [dppe: 1,2-bis(diphenylphosphino)ethane] gave a variety of polymerizable molecules (monomers)
with a 6,7-dihydro-5H-cyclopenta[c]pyridine core structure. Among the resulting monomers, 5-phenyl-1,3-
dihydrospiro[indene-2,30-oxetane] prepared from 3,3-di(prop-2-ynyl)oxetane and phenylacetylene was representa-
tively polymerized in the presence of BF3 catalyst. A cationic random copolymerization of one of 1,3-dihydrospiro-
[indene-2,30-oxetane] derivatives with 3-ethyl-3-(phenoxymethyl)oxetane and radical random copolymerization of
diethyl 5-(4-vinylphenyl)-1H-indene-2,2(3H)-dicarboxylate with styrene have also been demonstrated.
Introduction
reactions developed so far,3 the compatibility of polymerizable
functional groups (PGs) has not been investigated systematically.
First, we explored the stability of such functional moieties
under the conditions of the cycloaddition reaction catalyzed by
In the study of functional materials, polymer science is
increasingly important. For bottom-up development of new
functional polymers, the preparation of new polymerizable
molecules (monomers) with functional handles for compositional
versatility is desired.1
In contrast to the conventional, individual preparation of
monomers for planned polymerization, we propose a convergent
process that couples simple molecules having a polymerizable
functional group (PG) and a functional group(s) necessary for the
desired properties of the resulting polymers, the synthesis of
which enables a quick and easy access to diverse monomers
(a monomer library) and the corresponding polymers. To realize
this idea, the coupling reaction must have high functional group
a dipimp/CoCl2 6H2O/Zn reagent [dipimp: 2-(2,6-diisopropyl-
3
phenyl)-iminomethylpyridine] that we developed.4 Thus, the
cycloaddition reaction of diyne 1a with phenylacetylene (2a)
catalyzed by a dipimp/CoCl2 6H2O/Zn reagent was carried out
3
in the presence of the model molecules 6 having the PG depicted
in Scheme 2.
As a result, the reaction showed reasonably high PG compati-
bility. Thus, except for the reaction with carboxylic acid 6o and
aryl bromide 6p, the cycloaddition reaction proceeded smoothly
to produce adduct 4aa in good to quantitative yields. After the
workup, styrene (6a), 1,3-diene 6b, methacrylate 6c, phenol 6d,
amides 6e and 6f, aldehyde 6g, aryl chloride 6h, epoxide 6i,
oxetane 6j, and borate 6k were quantitatively recovered as
themselves. The reaction in the presence of acrylate6l, acrylamide
6m, or isocyanate 6n provided 4aa in good yield but they were not
recovered due to their polymerization (6l and 6m) or reaction
with water (6n). In the presence of compounds 6o and 6p, the
cycloaddition reaction did not proceed.
With these results in hand, we pursued synthesis of various
polymerizable molecules by the coupling of a series of diynes and
their alkyne (or nitrile) counterparts, 1a-e and 2a-m (or 3a-c)
(see Supporting Information for their structure). Representative
results are illustrated in Figure 1, where the part derived from diyne
1 and the part derived from alkyne 2 (or nitrile 3) are indicated in
red and blue, respectively. Thus, the reaction of 1 and 2 with a
ꢀ
compatibility. In this context, Frechet and Hawker et al. have
developed a synthesis of a variety of monomers comprised with a
4-vinyl-1,3,5-triazole structure by the Cu(I)-catalyzed cycloaddi-
tion of azides and alkynes and demonstrated their radical poly-
merizations.2 Herein is reported synthesis of a wider range of
polymerizable molecules of types 4 and 5 from diynes 1 with
alkynes 2 or nitriles 3 byusing a catalytic [2 þ 2 þ 2] cycloaddition
reaction as the coupling process (Scheme 1). Attributed to
molecular assembly by a combination of the starting alkynes
and nitriles, various monomers 4 and 5 can be prepapred; their
polymerization will give a variety of polymers such as types I, II,
and III. Alternative copolymerization with a combination of
these new monomers and also with conventional monomers
might open a broad range of new polymer families.
dipimp/CoCl2 6H2O/Zn catalyst in tetrahydrofuran (THF) at
3
Results and Discussion
ambient temperature gave 2,3-dihydro-1H-indenes 4 having a
polymerizable functionality such as an epoxide (4ab), active
alkene (4ac, 4ad, 4be, 4af, 4el), oxetane (4ca, 4cg, 4ck, 4el, 4cn),
ester (4ab, 4ac, 4ad, 4af, 4ah, 4ai, 4dj, 4di, 4am), alcohol
(4be, 4dj, 4am), phenol (4ah), amine (4ai, 4di) and borate (4cn)
Although a variety of functional groups tolerated under the
reaction conditions of catalyzed [2 þ 2 þ 2] alkyne-cycloaddition
*Corresponding author. E-mail: okamos10@kanagawa-u.ac.jp.
r 2010 American Chemical Society
Published on Web 02/05/2010
pubs.acs.org/Macromolecules

2214 Macromolecules, Vol. 43, No. 5, 2010
Watanabe et al.
Scheme 1. Concept of Rapid Assembly of Polymerizable Molecules by
[2 þ 2 þ 2] Cycloaddition Reactionsa
a PG1, PG2 = polymerizable functional groups. Keys: (i) alkyne
[2 þ 2 þ 2] cycloaddition reaction; (ii) polymerization.
Scheme 2. Investigation on Polymerizable-Functional Group
Compatibilitya
Figure 1. Synthesis of polymerizable molecules by [2 þ 2 þ 2] cyclo-
addition reaction; dipimp = 2-(2,6-diisopropylphenyl)iminomethyl-
pyridine, dppe = 1,2-bis(diphenylphosphino)ethane, THF = tetra-
hydrofuran, NMP = N-methyl-2-pyrrolidone, DMSO = dimethylsulf-
oxide, BHT = 2,6-di(tert-butyl)-4-methylphenol.
Scheme 3. Representative Polymerization of New Monomers 4a
a Key: dipimp
THF = tetrahydrofuran.
= 2-(2,6-diisopropylphenyl)iminomethylpyridine;
in good to excellent yields. In all these syntheses, no oligo-
meric or polymeric byproduct derived from 1, 2, and the
resulting 4 was detected. As exemplified by conversion of 4am
to 4am0, styrene derivatives were also prepared from the
corresponding alcoholic adducts by a dehydration reaction.
Similarly, with use of a dppe/CoCl2 6H2O/Zn [dppe: 1,2-bis-
3
(diphenylphosphino)ethane] catalyst5 instead of dipimp/CoCl2
3
6H2O/Zn, 6,7-dihydro-5H-cyclopenta-[c]pyridines 5 were obtained
by the reaction of diynes 1 and nitriles 3, albeit in a low yield
of 5cb.
a AIBN = 2,20-azobis(isobutyronitrile).
Among these monomers 4 obtained here, a few compounds
were representatively used for polymerization (Scheme 3). Thus,
a cationic polymerization of oxetane 4ca was carried out by
treatment with a catalytic amount of BF3 in CH2Cl2 at 0 °Ctoyield
the corresponding poly-4ca (Mn = 4.56 ꢀ 104, Mw = 2.23 ꢀ 105,
Mw/Mn = 4.89 based on gel permeation chromatography (GPC)
analysis, Tg = 106.9 °C) in 82% yield. A 5:1 mixture of styrene
and 4ac with a catalytic amount of 2,20-azobis(isobutyronitrile)
(AIBN) in toluene was heated to 60 °C to provide the correspond-
ing copolymer poly-(styrene-co-4ac) (Mn = 9.25 ꢀ 104, Mw
=
2.21 ꢀ 105, Mw/Mn = 2.39 based on GPC analysis, Tg = 102.9 °C,
81% of styrene incorporation) in 68% yield. Treatment of a

Article
Macromolecules, Vol. 43, No. 5, 2010 2215
mixture of 7 and 4ck (0.1 equiv) with 13 mol % of BF3-OEt2 in
CH2Cl2 afforded poly-(7-co-4ck) bearing triaryl phosphine oxide
pendants [Mn = 3.89 ꢀ 103, Mw = 1.09 ꢀ 104, Mw/Mn = 2.81
based on GPC analysis, m:n = 10:1, 31P NMR (CDCl3, 202 MHz)
δ -14.05] in 40% yield.
Et2O. The filtrate was concentrated to dryness and the resulting
colored residue was chromatographed on silica gel to give
314 mg of diethyl 5-((oxiran-2-ylmethoxy)methyl)-1H-indene-
1
2,2(3H)-dicarboxylate (4ab) in 90% yield. H NMR (CDCl3,
500 MHz): δ 7.19 (s, 1H, Ar), 7.17 (d, J = 7.5 Hz, 1H, Ar), 7.14
(d, J = 7.5 Hz, 1H, Ar), 4.56 (d, J = 11.5 Hz, 1H, ArCH2O),
4.50 (d, J = 11.5 Hz, 1H, ArCH2O), 4.20 (q, J = 7.2 Hz, 4H,
OCH2CH3), 3.75 (dd, J = 3.5, 11.5 Hz, 1H, epoxide), 3.58 (s,
2H, ArCH2C), 3.57 (s, 2H, ArCH2C), 3.42 (dd, J = 5.5, 11.5 Hz,
1H, epoxide), 3.20 - 3.16 (m, 1H, epoxide), 2.80 (dd, J = 4.0, 5.0
Hz, 1H, epoxide), 2.61 (dd, J = 2.8, 5.0 Hz, 1H, epoxide), 1.25 (t,
J = 7.2 Hz, 6H, OCH2CH3). 13C NMR (CDCl3, 125 MHz): δ
171.5, 140.3, 139.6, 136.6, 126.7, 124.1, 123.7, 73.3, 70.7, 61.6,
60.4, 50.8, 44.2, 40.3, 40.1, 14.0. IR (neat): 2982, 2934, 2905,
1732, 1466, 1445, 1366, 1253, 1185, 1158, 1094, 1012, 903, 825
cm-1. HRMS-ESI (m/z): calcd for C19H24NaO6 [M þ Na]þ,
371.1471; found, 371.1481.
Conclusion
We have demonstrated that a cobalt-catalyzed [2 þ 2 þ 2]
cycloaddition of functionalized alkynes yielded a variety of
polymerizable molecules (monomers). Their polymerization will
give a variety of polymers, and alternative copolymerization with
these new monomers and also conventional monomers might
open a broad range of new polymer families.
Experimental Section
Diethyl 5-(4-Vinylphenyl)-1H-indene-2,2(3H)-dicarboxylate
(4ac). The title (342 mg) compound was obtained from 1a
(236 mg, 1.0 mmol) and 2c (192 mg, 1.5 mmol) in 94% yield.
1H NMR (CDCl3, 500 MHz): δ 7.50 (d, J = 8.0 Hz, 2H, Ar),
7.43 (d, J = 8.0 Hz, 2H, Ar), 7.40 (s, 1H, Ar), 7.38 (d, J = 7.5 Hz,
1H, Ar), 7.23 (d, J = 7.5 Hz, 1H, Ar), 6.72 (dd, J = 11.0,
17.5 Hz, 1H, ArCHdCH2),5.75(d,J= 17.5 Hz, 1H, ArCHdCH2),
5.23 (d, J = 11.0 Hz, 1H, ArCHdCH2), 4.20 (q, J = 7.5 Hz, 4H,
OCH2CH3), 3.64 (s, 2H, ArCH2C), 3.62 (s, 2H, ArCH2C), 1.24
(t, J = 7.5 Hz, 6H, OCH2CH3). 13C NMR (CDCl3, 125 MHz): δ
171.5, 140.6, 140.5, 139.6, 139.2, 136.3, 127.0, 126.5, 125.8,
124.4, 122.6, 113.6, 61.6, 60.4, 40.4, 40.1, 14.0, 13.9. IR (neat):
2980, 2936, 2904, 1733, 1628, 1488, 1365, 1277, 1244, 1186, 1157,
1067, 819 cm-1. HRMS-ESI (m/z): calcd for C23H24NaO4
[M þ Na]þ, 387.1572; found, 387.1556.
General Data. NMR spectra were recorded in CDCl3 at
600, 500, 270, and 90 MHz for 1H and 150, 125, 67.5, and
22.5 MHz for 13C on JEOL JNM-ECA600, -ECA500, -EX270,
and HITACHI R-1900 spectrometers, respectively. Chemical
shifts are reported in parts per million (ppm, δ) relative to Me4Si
1
(δ 0.00) or residual CHCl3 (δ 7.26 for H NMR) and CDCl3
(δ 77.0 for 13C NMR). IR spectra were recorded on JASCO IR
FT/IR 4100 spectrometer. High-resolution mass spectra (HR-
MS) were measured on JEOL Accu TOF T-100 equipped with
an ESI ionization unit. The Mn and Mw/Mn of polymers were
measured with a TOSOH HLC-8020 gel-permeation chromato-
graphy (GPC) unit (eluent: tetrahydrofuran (THF); calibration:
polystyrene standards) using two TSK-gel columns (2 ꢀ Multi-
pore HXL-M). Thermogravimetry/differential thermal analysis
(TG/DTA) was carried out with Seiko Instruments Inc. EX-
STAR6000 TG/DTA6200 under nitrogen (heating rate:10 °C/min).
All reactions sensitive to oxygen and/or moisture were per-
formed under an argon atmosphere. Dry solvents [tetrahydro-
furan (THF), N,N-dimethylformamide (DMF), dichloro-
methane (CH2Cl2), toluene, N-methyl-2-pyrrolidone (NMP)
and diethyl ether (ether)] were purchased from Kanto Chemi-
cals. 2-(2,6-Diisopropylphenyliminomethyl)pyridine (dipimp)
was prepared from pyridine 2-carboxaldehyde and 2,6-diiso-
propylaniline by the reported procedure.6 For the structures and
preparation of diynes 1a-e, alkynes 2a-m and nitriles 3a-c, see
the Supporting Information.
Diethyl 5-(Methoxymethyl)-6-(4-vinylphenyl)-1H-indene-
2,2(3H)-dicarboxylate (4ad). The title compound (371 mg)
was obtained from 1a (236 mg, 1.0 mmol) and 2d (258 mg, 1.5
mmol) in 91% yield. 1H NMR (CDCl3, 500 MHz): δ 7.45 (d,
J = 8.3 Hz, 2H, Ar), 7.36 (s, 1H, Ar), 7.31 (d, J = 8.3 Hz, 2H,
Ar), 7.11 (s, 1H, Ar), 6.76 (dd, J = 11.0, 17.5 Hz, 1H, ArCH =
CH2), 5.80 (d, J = 17.5 Hz, 1H, ArCHdCH2), 5.28 (d, J =
11.0 Hz, 1H, ArCHdCH2), 4.27 (s, 2H, ArCH2O), 4.22 (q,
J = 7.0 Hz, 4H, OCH2CH3), 3.64 (s, 2H, ArCH2C), 3.61 (s,
2H, ArCH2C), 3.33 (s, 3H, OCH3), 1.27 (t, J = 7.0 Hz, 6H,
OCH2CH3). 13C NMR (CDCl3, 125 MHz): δ 171.6, 140.5,
140.4, 139.7, 139.5, 136.5, 136.2, 134.2, 129.5, 125.9, 125.6,
124.9, 113.8, 76.7, 72.5, 61.7, 60.5, 58.1, 40.2, 14.0. IR (neat):
General Procedure for Investigating Functional Group Com-
patibility of Cobalt-Catalyzed [2 þ 2 þ 2] Cycloaddition Reac-
tion. A solution of CoCl2 6H2O (5.9 mg, 0.025 mmol) and
2980, 2929, 2901, 1729, 1628, 1446, 1245, 1068, 907, 850 cm-1
.
3
dipimp (7.9 mg, 0.030 mmol) in THF (1.0 mL) was added to
zinc powder (3.3 mg, 0.05 mmol). The resulting mixture was
stirred at ambient temperature for 1 h. A solution of R,R-
dipropargyl malonic diethyl ester (1a) (118.1 mg, 0.5 mmol),
ethynylbenzene (2a) (66.4 mg, 0.65 mmol), compound 6 (0.50
mmol) in THF (1.0 mL) was added, and the resulting mixture
was stirred at room temperature. The reaction progress was
checked by TLC analysis. After complete consumption of diyne
2a, Et2O was added and the mixture was passed through a pad of
Celite with Et2O. After concentration, the crude residue was
HRMS-ESI (m/z): calcd for C25H28NaO5 [M þ Na]þ,
431.1834; found, 431.1809.
(5,6-Bis(hydroxymethyl)-2,3-dihydro-1H-inden-2-yl)methyl
2-Methylprop-2-enoate (4be). The title compound (207 mg)
was obtained from 1b (190 mg, 1.0 mmol) and 2e (261 mg,
3.0 mmol) in 75% yield. 1H NMR (CDCl3, 500 MHz): δ 7.20
(s, 2H, Ar), 6.08 (s, 1H, CdCH2), 5.58-5.55 (m, 1H, CdCH2),
4.69 (s, 4H, ArCH2OH), 4.23 (s, 2H, OH), 4.16 (d, J = 7.5 Hz,
2H, OCH2CH), 3.08 (dd, J = 8.0, 15.5 Hz, 2H, ArCH2CH),
2.88 (quint, J = 6.7 Hz, 1H, CH(CH2)3), 2.76 (dd, J = 6.3,
16.3 Hz, 2H, ArCH2CH), 1.93 (s, 3H, CH3). 13C NMR
(CDCl3, 125 MHz): δ 167.5, 142.8, 137.8, 136.2, 126.1,
125.6, 67.6, 64.2, 38.4, 35.7, 18.3. IR (KBr): 3358, 2929,
2873, 1713, 1634, 1453, 1299, 1173 cm-1. HRMS-ESI
(m/z): calcd for C16H20NaO4 [M þ Na]þ, 299.1259; found,
299.1281.
1
analyzed by H NMR to confirm the progress of the reaction
and recovery of compound 6.
Typical Procedure for Synthesis of Monomers 4 from Diynes 1
and Alkynes 2. A 20 mL Schlenk tube was charged with zinc
powder (40-100 mesh, 6.5 mg, 0.10 mmol) and purged with
argon. A solution of CoCl2 6H2O (11.9 mg, 0.05 mmol) and
3
dipimp (16.0 mg, 0.06 mmol) in THF (2.0 mL) was added, and
the resulting mixture was stirred at ambient temperature for 1 h.
A solution of R,R-dipropargyl diethyl malonate (1a) (236 mg,
1.0 mmol) and 2-((prop-2-ynyloxy)methyl)oxirane (2b) (168 mg,
1.5 mmol) in THF (2.0 mL) was added and the mixture was
stirred at 40 °C. The reaction progress was checked by TLC
analysis. After complete consumption of 1a, Et2O (4 mL) was
added and the mixture was passed through a pad of Celite with
Diethyl 5-((2-Methylprop-2-enoyloxy)methyl)-1H-indene-
2,2(3H)-dicarboxylate (4af). The title compound (350 mg)
was obtained from 1a (236 mg, 1.0 mmol) and 2f (372 mg,
3.0 mmol) in 97% yield. 1H NMR (CDCl3, 500 MHz): δ 7.21
(s, 1H, Ar), 7.18 (br s, 2H, Ar), 6.14 (br s, 1H, CdCH2), 5.59
- 5.50 (m, 1H, CdCH2), 5.14 (s, 2H, ArCH2O), 4.20 (q, J =
7.3 Hz, 4H, OCH2CH3), 3.59 (s, 2H, ArCH2C), 3.58 (s, 2H,
ArCH2C), 1.96 (s, 3H, CH3), 1.26 (t, J = 7.3 Hz, 6H,

2216 Macromolecules, Vol. 43, No. 5, 2010
Watanabe et al.
OCH2CH3). 13C NMR (CDCl3, 150 MHz): δ 171.5,167.3,
140.5, 140.1, 136.2, 134.9, 127.1, 125.8, 124.2, 124.1, 66.4,
61.7, 60.4, 40.3, 40.2, 18.3, 14.0. IR (neat): 2982, 2936, 2905,
2874, 1730, 1635, 1589, 1445, 1368, 1317, 1294, 1252, 1184,
1157, 1069, 1053, 1013, 943, 860, 816 cm-1. HRMS-ESI
(m/z): calcd for C20H24NaO6 [M þ Na]þ, 383.1471; found,
383.1451.
Ethyl 5-(Aminomethyl)-2,3-dihydro-1H-indene-2-carboxylate
(4di). The title compound (125 mg) was obtained from 1d
(164 mg, 1.0 mmol) and 2i (165 mg, 3.0 mmol) in 57% yield.
1H NMR (CDCl3, 500 MHz): δ 7.18 (s, 1H, Ar), 7.16 (d, J =
8.0 Hz, 1H, Ar), 7.10 (d, J = 8.0 Hz,1H, Ar), 4.17 (q, J = 7.3 Hz,
2H, OCH2CH3), 4.15 (s, 2H, ArCH2NH2), 3.31 (quint, J =
8.4 Hz, 1H, CH(CH2)3), 3.26 - 3.15 (m, 4H, ArCH2CH), 2.66
(br s, 2H, NH2), 1.28 (t, J = 7.3 Hz, 3H, OCH2CH3). 13C NMR
(CDCl3, 125 MHz): δ 175.2, 142.1, 140.7, 140.4, 125.8, 124.3,
123.3, 60.6, 46.0, 43.7, 36.0, 35.8, 14.2. IR (neat): 3383, 2978,
2947, 2909, 2872, 1732, 1566, 1532, 1483, 1435, 1371, 1335, 1231,
1211, 1175, 1034, 812 cm-1. HRMS-ESI (m/z): calcd for
(C13H18NO2)þ 220.1338; found, 220.1354.
(5-Butyl-1,3-dihydrospiro[indene-2,30-oxetane]-6-yl)diphenyl-
phosphine Oxide (4ck). The title compound (221 mg) was
obtained from 1c (201 mg, 1.5 mmol) and 2k (282 mg, 1.0
mmol) in 53% yield. 1H NMR (CDCl3, 500 MHz): δ 7.68-7.55
(m, 4H, Ar), 7.55-7.52 (m, 2H, Ar), 7.48-7.45 (m, 4H, Ar),
7.19 (d, 1H, JP-H = 3.5 Hz, Ar), 6.94 (d, 1H, JP-H = 14.0 Hz,
Ar), 4.66 (d, 2H, J = 6.5 Hz, oxetane), 4.63 (d, 2H, J = 6.5 Hz,
oxetane), 3.26 (s, 2H, cyclic CH2), 3.11 (s, 2H, cyclic CH2), 2.77
(t, 2H, J = 8.0 Hz, ArCH2CH2), 1.29 (m, 2H, acyclic CH2), 1.10
(m, 2H, acyclic CH2), 0.70 (t, 3H, J = 7.3 Hz, CH3). 13C NMR
5-Phenyl-1,3-dihydrospiro[indene-2,30-oxetane] (4ca). The title
compound (175 mg) was obtained from 1c (134 mg, 1.0 mmol)
and 2a (153 mg, 1.5 mmol) in 74% yield. H NMR (CDCl3,
1
500 MHz): δ 7.55 (d, J = 6.5 Hz, 2H, Ar), 7.47 - 7.36 (m, 4H,
Ar), 7.33 (d, J = 7.5 Hz, 1H, Ar), 7.28 (d, J = 8.0 Hz, 1H, Ar),
4.71 (s, 4H, oxetane ring), 3.31 (s, 2H, ArCH2C), 3.29 (s, 2H,
ArCH2C). 13C NMR (CDCl3, 125 MHz): δ 142.3, 141.3, 140.7,
140.2, 128.7, 127.09, 127.05, 125.9, 124.8, 123.4, 83.6, 47.0, 44.1,
43.8. IR (neat): 2947, 2905, 2924, 2849, 1476, 1427, 1304, 1223,
974, 943, 829, 732, 692 cm-1. HRMS-ESI (m/z): calcd for
C17H16NaO [M þ Na]þ, 259.1108; found, 259.1099.
tert-Butyl 3-(1,3-dihydrospiro[indene-2,30-oxetane]-5-yl)phe-
nyl Carbonate (4cg). The title compound (254 mg) was obtained
from 1c (134 mg, 1.0 mmol) and 2g (327 mg, 1.5 mmol) in 72%
1
yield. H NMR (CDCl3, 500 MHz): δ 7.44-7.32 (m, 5H, Ar),
7.25 (d, J = 8.0 Hz, 1H, Ar), 7.16-7.12 (m, 1H, Ar), 4.70 (s, 4H,
oxetane ring), 3.29 (s, 2H, ArCH2C), 3.28 (s, 2H, ArCH2C), 1.58
(s, 9H, t-Bu). 13C NMR (CDCl3, 125 MHz): δ 151.8, 151.3,
142.8, 142.3, 141.1, 139.0, 129.5, 125.8, 124.8, 124.3, 123.3,
119.9, 119.8, 83.45, 83.42, 46.9, 43.9, 43.7, 27.6. IR (neat):
2975, 2939, 2860, 1752, 1474, 1427, 1369, 1279, 1253, 1157,
973 cm-1. HRMS-ESI (m/z): calcd for C22H24NaO4 [M þ
Na]þ, 375.1572; found, 375.1595.
(CDCl3, 125 MHz): δ 147.1 (d, JCP = 9.6 Hz), 146.2 (d, JCP
2.9 Hz), 138.5 (d, JCP = 14 Hz), 131.93, 131.9 (d, JCP = 9.6 Hz),
131.6 (d, JCP = 2.9 Hz), 129.3 (d, JCP = 13 Hz), 129.2 (d, JCP
=
=
14 Hz), 128.4 (d, JCP = 12 Hz), 126.9 (d, JCP = 11 Hz), 83.4,
46.8, 44.1, 43.6, 34.0 (d, JCP = 4.8 Hz), 33.6, 22.7, 13.8. 31P
NMR (CDCl3, 202 MHz): δ 31.30. IR (neat): 2956, 2928, 2867,
2607, 1465, 1437, 1164 cm-1. HRMS-ESI (m/z): calcd for
(C30H35O3P)þ 417.19834; found, 417.20139.
Diethyl 5-(3-Hydroxyphenyl)-1H-indene-2,2(3H)-dicarboxy-
late (4ah). The title compound (351 mg) was obtained from 1a
(236 mg, 1.0 mmol) and 2h (177 mg, 1.5 mmol) in 99% yield. 1H
NMR (CDCl3, 500 MHz): δ 7.37 (s, 1H, Ar), 7.35 (d, J = 7.4 Hz,
1H, Ar), 7.28-7.20 (m, 2H, Ar), 7.10 (d, J = 7.4 Hz, 1H, Ar),
7.00 (d, J = 2.3 Hz, 1H, Ar), 6.79 (dd, J = 3.4, 8.0 Hz, 1H, Ar),
5.42 (br, 1H, ArOH), 4.22 (q, J = 7.2 Hz, 4H, OCH2CH3), 3.64
(s, 2H, ArCH2C), 3.62 (s, 2H, ArCH2C), 1.26 (t, J = 7.2 Hz, 6H,
OCH2CH3). 13C NMR (CDCl3, 125 MHz): δ 171.8, 156.0,
142.9, 140.6, 139.9, 139.3, 129.8, 126.1, 124.4, 122.9, 119.5,
114.0, 113.9, 61.8, 60.5, 40.4, 40.2, 14.0. IR (neat): 3444, 2980,
2936, 2905, 1730, 1714, 1599, 1573, 1478, 1248, 1068, 782,
695 cm-1. HRMS-ESI (m/z): calcd for C21H22NaO5 [M þ Na]þ,
377.1395; found, 377.1365.
3-Ethyl-3-(((2-((4-vinylbenzyloxy)methyl)-2,3-dihydro-1H-in-
den-5-yl)methoxy)methyl)oxetane (4el). The title compound
(295 mg) was obtained from 1e (201 mg, 1.0 mmol) and 2l
(210 mg, 1.5 mmol) in 78% yield. 1H NMR (CDCl3, 600 MHz):
δ 7.39 (d, 2H, J = 8.2 Hz, Ar), 7.30 (d, 2H, J = 8.2 Hz, Ar), 7.17
(s, 1H, Ar), 7.16 (d, 1H, J = 7.9 Hz, Ar), 7.10 (d, 1H, J = 7.9 Hz,
Ar), 6.71 (dd, 1H, J = 10.7, 17.2 Hz, ArCH = CH2), 5.74 (d,
1H, J = 17.2 Hz, ArCHdCH2), 5.24 (d, 1H, J = 10.7 Hz,
ArCHdCH2), 4.524 (s, 2H, ArCH2O), 4.520 (s, 2H, ArCH2O),
4.51 (d, 2H, J = 5.4 Hz, oxetane), 4.36 (d, 2H, J = 5.4 Hz,
oxetane), 3.51 (s, 2H, OCH2C), 3.48 (d, 2H, J = 6.9 Hz,
OCH2CH), 3.10 - 3.03 (m, 2H, CH2CHCH2), 2.86 -2.78 (m,
1H, CH2CHCH2), 2.77 - 2.70 (m, 2H, CH2CHCH2), 1.33 (s,
3H, CH3). 13C NMR (CDCl3, 150 MHz): δ 143.2, 142.5, 138.1,
136.9, 136.5, 136.3, 127.8, 126.2, 125.9, 124.5, 124.1, 113.7, 80.2,
75.3, 74.0, 73.6, 72.8, 39.8, 39.2, 36.1, 35.9, 21.4. IR (neat): 2931,
2862, 1628, 1511, 1361, 1093 cm-1. HRMS-ESI (m/z): calcd for
C25H30NaO3 [M þ Na]þ, 401.2093; found, 401.2041.
Diethyl 5-(Aminomethyl)-1H-indene-2,2(3H)-dicarboxylate
(4ai). The title compound (236 mg) was obtained from 1a
(236 mg, 1.0 mmol) and 2i (165 mg, 3.0 mmol) in 81% yield.
1H NMR (CDCl3, 500 MHz): δ 7.17 (s, 1H, Ar), 7.15 (d, J =
7.5 Hz, 1H, Ar), 7.11 (d, J = 7.5 Hz, 1H, Ar), 4.20 (q, J =
7.2 Hz, 4H, OCH2CH3), 3.82 (s, 2H, ArCH2NH2), 3.57 (s, 2H,
ArCH2C), 3.56 (s, 2H, ArCH2C), 1.99 (br, 2H, ArCH2NH2),
1.25 (t, J = 7.2 Hz, 6H, OCH2CH3). 13C NMR (CDCl3,
125 MHz): δ 171.6, 141.6, 140.5, 138.7, 126.1, 124.2, 123.1,
61.7, 60.5, 46.2, 40.4, 40.1, 14.0. IR (neat): 3370, 3299, 2935,
2905, 2871, 1671, 1584, 1525, 1495, 1386, 1115, 1012, 943, 901,
Diethyl 5-(1-hydroxyethyl)-1H-indene-2,2(3H)-dicarboxylate
(4am). The title compound (248 mg) was obtained from 1a
(236 mg, 1.0 mmol) and 2m (210 mg, 3.0 mmol) in 81% yield.
1H NMR (CDCl3, 500 MHz): δ 7.22 (s, 1H, Ar), 7.16 (br s, 2H,
Ar), 4.86 (q, J = 6.9 Hz, 1H, ArCHOH), 4.20 (q, J = 7.3 Hz,
4H, OCH2CH3), 3.58 (s, 2H, ArCH2C), 3.57 (s, 2H, ArCH2C),
1.75 (br, 1H, ArCHOH), 1.48 (d, 1H, J = 6.9 Hz, CH-
(OH)CH3), 1.26 (t, J = 7.3 Hz, 6H, OCH2CH3). 13C NMR
(CDCl3, 125 MHz): δ 171.9, 145.0, 139.6, 127.6, 124.6, 124.4,
121.5, 70.7, 62.0, 60.7, 40.7, 40.4, 25.4, 14.3. IR (neat): 3526,
819 cm-1
292.1549; found, 292.1545.
.
HRMS-ESI (m/z): calcd for (C16H22NO4)þ
Ethyl 5-(Hydroxymethyl)-2,3-dihydro-1H-indene-2-carboxy-
late (4dj). The title compound (97 mg) was obtained from 1d
(164 mg, 1.0 mmol) and 2j (168 mg, 3.0 mmol) in 44% yield. 1H
NMR (CDCl3, 500 MHz): δ 7.23 (s, 1H, Ar), 7.19 (d, J = 7.5 Hz,
1H, Ar), 7.15 (d, J = 7.5 Hz,1H, Ar), 4.65 (s, 2H, ArCH2OH),
4.18 (q, J = 7.0 Hz, 2H, OCH2CH3), 3.33 (quint, J = 8.5 Hz,
1H, CH(CH2)3), 3.28 - 3.17 (m, 4H, ArCH2CH), 1.28 (t, J =
7.0 Hz, 3H, OCH2CH3). 13C NMR (CDCl3, 125 MHz): δ 176.1,
143.0, 142.1, 140.3, 126.5, 125.2, 124.0, 66.3, 61.5, 44.6, 36.9,
36.8, 15.1. IR (neat): 3445, 2979, 2937, 2855, 1731, 1493, 1440,
1372, 1348, 1261, 1208, 1173, 1033, 820 cm-1. HRMS-ESI
(m/z): calcd for C13H16NaO3 [M þ Na]þ, 243.0997; found,
243.0981.
2977, 2932, 2905, 1729, 1445, 1250, 1069, 1012, 860 cm-1
.
HRMS-ESI (m/z): calcd for C17H22NaO5 [M þ Na]þ, 329.1365;
found, 329.1362.
2-(4-(1,3-Dihydrospiro[indene-2,30-oxetane]-5-yl)phenyl)-4,4,5,5-
tetramethyl-1,3,2-dioxaborolane (4cn). The title compound (264 mg)
was obtained from 1c (201 mg, 1.5 mmol) and 2n (228 mg, 1.0 mmol)
in 73% yield. 1H NMR (CDCl3, 500 MHz): δ 7.86 (d, J = 8.0 Hz,
2H, Ar), 7.57 (d, J = 8.0 Hz, 2H, Ar), 7.46 (s, 1H, Ar), 7.42 (d, J =
8.0 Hz, 1H, Ar), 7.27 (d, J = 8.0 Hz, 1H, Ar), 4.70 (s, 4H, oxetane
ring), 3.30 (s, 2H, ArCH2C), 3.29 (s, 2H, ArCH2C), 1.36 (s, 12H,
OCCH3).13CNMR(CDCl3,125MHz):δ144.0, 142.3, 141.1, 139.9,

Article
Macromolecules, Vol. 43, No. 5, 2010 2217
135.2, 126.37, 126.35, 126.0, 124.9, 123.4, 83.8, 83.5, 47.0, 44.0, 43.8,
.
PyCH2C). 13C NMR (CDCl3, 125 MHz): δ 152.9, 148.6, 145.7,
137.2, 118.6, 117.2, 82.9, 46.9, 43.6, 41.1, 26.4. IR (neat): 2961,
24.9. IR (neat): 2980, 2931, 2861, 1608, 1396, 1360, 1144 cm-1
HRMS-ESI (m/z): calcd for C23H27BKO3 [M þ K]þ, 401.1960;
2930, 2864, 2252, 1608, 1485, 1260, 1094, 1022, 974, 801 cm-1
.
found, 401.1936.
HRMS-ESI (m/z): calcd for C12H12N2NaO1 [M þ Na]þ,
Diethyl 5-Vinyl-1H-indene-2,2(3H)-dicarboxylate (4am0).
p-Toluene sulfonic acid hydrate (5.2 mg, 0.03 mmol) and
2,6-di-tert-butyl-4-methylphenol (∼0.1 mg, ∼0.5 μmol) were
added to a solution of 4am (306 mg, 1.0 mmol) in dimethyl
sulfoxide (3.3 mL) and the resulting mixture was heated to
140 °C for 3 h. After being cooled to room temperature, the
mixture was quenched by addition of aqueous saturated
NaHCO3 and extracted with CH2Cl2. The combined organic
layers were washed with brine, dried over MgSO4, filtered
through a pad of Celite and concentrated in vacuo. The
residue was chromatographed on silica gel to give 4am0
(210 mg) in 73% yield as an yellow oil. 1H NMR (CDCl3,
500 MHz): δ 7.26 (s, 1H, Ar), 7.21 (d, J = 7.8 Hz, 1H, Ar), 7.14
(d, J = 7.8 Hz, 1H, Ar), 6.68 (dd, J = 10.9, 17.2 Hz, 1H,
ArCH = CH2), 5.69 (d, J = 17.2 Hz, 1H, ArCHdCH2), 5.18
(d, J = 10.9 Hz, 1H, ArCHdCH2), 4.20 (q, J = 7.2 Hz, 4H,
OCH2CH3), 3.58 (s, 2H, ArCH2C), 3.57 (s, 2H, ArCH2C),
1.26 (t, J = 7.3 Hz, 6H, OCH2CH3). 13C NMR (CDCl3, 125
MHz): δ 171.5, 140.2, 139.8, 136.8, 136.6, 125.4, 124.2, 121.7
113.1, 61.7, 60.4, 40.3, 40.2, 14.0. IR (neat): 2981, 2936, 2905,
1730, 1455, 1278, 903, 860, 827 cm-1. HRMS-ESI (m/z):
calcd for C17H20NaO4 [M þ Na]þ, 311.1259; found, 311.1227.
General Procedure for Synthesis of Monomers 5 from Diynes
223.0847; found, 223.0826.
BF3-Catalyzed Cationic Polymerization of 4ca. BF3 Et2O
3
(2.1 mg, 0.1 mmol) was added to a solution of 4ca (236 mg, 1.0
mmol) in dry CH2Cl2 (0.4 mL). After stirring for 8 h at 0 °C, the
reaction mixture was poured into methanol containing a few
drops of aqueous ammonia and was filtered. The cake was dried
under reduced pressure. The residue was twice precipitated in
chloroform/methanol, and the solid was dried in vacuo to yield
poly-4ca (194 mg) in 82% yield as a white solid: 1H NMR
(CDCl3, 500 MHz): δ 7.48-7.41 (m, 2H ꢀ n, Ar), 7.34-7.19 (m,
5H ꢀ n, Ar), 7.09-7.03 (br s, 1H ꢀ n, Ar), 3.26 (br s, 4H ꢀ n,
OCH2C), 2.74 (br s, 1H ꢀ n, ArCH2C), 2.73 (br s, 1H ꢀ n,
ArCH2C). 13C NMR (CDCl3, 125 MHz): δ 148.3, 141.8, 139.7,
137.2, 136.4, 128.3, 126.4, 125.9, 124.4, 122.4, 83.6, 79.8, 46.9,
44.1, 43.7, 43.6, 41.7. IR (film) 3057, 3029, 2845, 2788, 1600,
1570, 1480, 1457, 1433, 1362, 1263, 1223, 1109, 1020, 898, 758,
697 cm-1. Mn = 4.56 ꢀ 104, Mw = 2.23 ꢀ 105, Mw/Mn = 4.89
based on GPC analysis. Tg = 106.9 °C.
BF3-Catalyzed Cationic Random Copolymerization of Oxe-
tanes 7 and 4ck. BF3 Et2O (35.1 mg, 0.25 mmol) was added to a
3
solution of oxetane 7 (365 mg, 1.9 mmol) and 4ck (80.0 mg,
0.19 mmol) in CH2Cl2 (18.5 mL) at 0 °C. The solution was
stirred for 72 h at room temperature and then quenched by
addition of aqueous saturated NaHCO3. The resulting mixture
was extracted with CH2Cl2. The combined organic layers were
washed with aqueous NaCl, dried over Na2SO4, filtered through
a pad of Celite, and concentrated in vacuo. The residue was twice
precipitated in ether/hexane and dried in vacuo to give poly(7-co-
4ck) (172 mg) in 40% yield as a white solid: 1H NMR (CDCl3,
500 MHz): δ 7.72-7.60 (br, 4H ꢀ n, Ar), 7.55-7.37 (br, 6H ꢀ n,
Ar), 7.23-7.10 (br, 2H ꢀ n, Ar), 6.93-6.67 (br, 3H, Ar),
3.92-3.58 (br, 2H ꢀ n, CCH2O), 3.42-3.00 (br, 4H ꢀ n,
CH2CCH2), 2.81-2.35 (br, 4H ꢀ n, cyclic), 1.59-1.22 (br, 2H
ꢀ n, CCH2CH3), 0.93-0.54 (br, 3H ꢀ n, CCH2CH3). 13C NMR
(CDCl3, 125 MHz): δ 159.4, 131.94, 131.86, 129.2, 128.4, 128.3,
120.3, 114.5, 71.5, 68.6, 43.1, 33.9, 33.6, 23.3, 23.17, 23.14, 22.7,
13.8, 7.7. 31P NMR (CDCl3, 202 MHz): δ -14.05. IR (film)
2963, 2905, 1599, 1497, 1261, 1169, 1096 cm-1. Mn = 3.89 ꢀ 103,
1 and Alkynes 3. A solution of CoCl2 6H2O (11.9 mg, 0.05
3
mmol) and 1,2-bis(diphenylphosphino)ethane (23.9 mg, 0.06
mmol) in N-methyl-2-pyrrolidone (2.0 mL for synthesis of 5cb
and 5cc) or acetonitrile (4.0 mL for synthesis of 5ca) was
added to a mixture of diyne 1c (134 mg, 1.0 mmol), nitrile 3
(2-cyanopyridine: 312 mg, 3.0 mmol or malononitrile: 99 mg,
1.5 mmol) and zinc powder (6.5 mg, 0.10 mmol), and the
resulting mixture was stirred at 50 °C. The reaction progress
was checked by TLC analysis. After complete consumption of
1c, ethyl acetate was added and the mixture was passed through
a pad of Celite with ethyl acetate. The filtrate was concentrated
to dryness and the resulting colored residue was chromato-
graphed on silica gel to give the corresponding pyridine 5.
3-Methyl-5,7-dihydrospiro[cyclopenta[c]pyridine-6,30-oxetane]
(5ca). The title compound (102 mg) was obtained from 1c
(134 mg, 1.0 mmol) and acetonitrile (3a: 4.0 mL, ∼80 mmol)
in 58% yield. 1H NMR (CDCl3, 500 MHz): δ 8.33 (s, 1H, Py),
7.03 (s, 1H, Py), 4.68 (d, J = 6.3 Hz, 2H, oxetane), 4.66 (d, J =
6.3 Hz, 2H, oxetane), 3.24 (s, 2H, PyCH2C), 3.22 (s, 2H,
PyCH2C), 2.51 (s, 3H, CH3). 13C NMR (CDCl3, 125 MHz): δ
156.5, 151.5, 144.9, 134.6, 119.5, 83.1, 46.9, 43.6, 41.1, 24.2. IR
(neat): 3007, 2928, 2862, 1611, 1561, 1487, 1429, 1392, 1247,
1233, 977, 923, 830 cm-1. HRMS-ESI (m/z): calcd for
(C11H14NO)þ 176.1075; found, 176.1067.
M
w = 1.09 ꢀ 104, Mw/Mn = 2.81 based on GPC analysis.
Radical Random Copolymerization of 4ac and Styrene. A
solution of 2,20-azobis(isobutyronitrile) (5.4 mg, 0.028 mmol)
in dry toluene (1.0 mL) was added to a mixture of 4ac (364 mg,
1.0 mmol) and styrene (521 mg, 5.0 mmol). After heating to
60 °C for 24 h, the reaction mixture was poured into methanol
and the precipitated solid was collected by filtration. The
resulting solid was dried under reduced pressure. The residue
was twice precipitated in chloroform/methanol and dried in
vacuo to give poly(styrene-co-4ac) (194 mg) in 68% yield as a
white solid: 1H NMR (CDCl3, 500 MHz): δ 7.45-6.27 (br, Ar
from 4ac and styrene), 4.22 (br s, OCH2CH3 from 4ac), 3.95
(br s, ArCH2C from 4ac), 2.11-1.20 (br s, ArCHCH2, ArCHCH2,
OCH2CH3 from 4ac and ArCHCH2, ArCHCH2 from styrene).
13C NMR (CDCl3, 125 MHz): δ 171.7, 145.2, 140.6, 138.7, 127.9,
127.8, 127.6, 127.4, 127.3, 126.6, 125.9, 125.6, 125.5, 124.4, 122.7,
61.7, 60.5, 40.5, 40.2, 14.0. IR (film) 3081, 3059, 3025, 2979, 2924,
2849, 1732, 1600, 1582, 1492, 1452, 1366, 1244, 1186, 1156, 1067,
817, 759, 543 cm-1. Mn =9.25ꢀ 104, Mw =2.21ꢀ 105, Mw/Mn =
3-(Pyridin-2-yl)-5,7-dihydrospiro[cyclopenta[c]pyridine-6,30-
oxetane] (5cb). The title compound (59 mg) was obtained from
1c (134 mg, 1.0 mmol) and 2-cyanopyridine (3b: 312 mg, 3.0
mmol) in 25% yield. 1H NMR (CDCl3, 500 MHz): δ 8.66 (d,
J = 4.5 Hz, 1H, Py), 8.65 (s, 1H, Py), 8.34 (d, J = 8.0 Hz, 1H,
Py), 8.27 (s, 1H, Py), 7.81-7.78 (m, 1H, Py), 7.30-7.27 (m, 1H,
Py), 4.70 (d, J = 6.3 Hz, 2H, oxetane), 4.69 (d, J = 6.3 Hz, 2H,
oxetane), 3.32 (s, 4H, PyCH2C). 13C NMR (CDCl3, 125 MHz):
δ 156.2, 154.9, 152.1, 149.0, 145.0, 137.8, 136.8, 123.4, 121.0,
117.2, 83.0, 46.9, 43.6, 41.3. IR (KBr) 2958, 2948, 2920, 2877,
1
2854, 1605, 1586, 1552, 1464, 1425, 1381, 974, 795, 746 cm-1
.
2.39 based on GPC analysis, Tg = 102.9 °C. H NMR spectra
HRMS-ESI (m/z): calcd for C15H14ClN2O [M þ Cl]-
indicated 81% of styrene incorporation.
275.0765; found, 275.0714.
2-(5,7-Dihydrospiro[cyclopenta[c]pyridine-6,30-oxetane]-3-yl)-
ethanenitrile (5cc). The title compound (126 mg) was obtained
from 1c (134 mg, 1.0 mmol) and malononitrile (3c: 99 mg, 1.5
mmol) in 25% yield. 1H NMR (CDCl3, 500 MHz): δ 8.41 (s, 1H,
Py), 7.32 (s, 1H, Py), 4.70 (d, J = 6.3 Hz, 2H, oxetane), 4.68 (d,
J = 6.3 Hz, 2H, oxetane), 3.90 (s, 2H, PyCH2CN), 3.29 (br s, 2H,
Acknowledgment. We thank the Scientific Frontier Research
Project from the Ministry of Education, Culture, Sports, Science,
and Technology, Japan for financial support.
Supporting Information Available: Text giving a detailed
experimental section including experimental procedures and

2218 Macromolecules, Vol. 43, No. 5, 2010
Watanabe et al.
ꢀ
figures showing the structures and spectroscopic data of com-
pounds 1, 2, 4, 5 and the polymers. This material is available free
of charge via the Internet at http://pubs.acs.org.
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