Controlled regioregularity in oligo(2-methoxy-5-(2′-ethylhexyloxy)-1, 4-phenylenevinylenes

Article abstract of DOI:10.1021/jo501266g

A series of three pentameric derivatives of 2-methoxy-5-(2′- ethylhexyloxy)-p-phenylenevinylenes (2-4), with varying degrees of side chain regioregularity, was prepared. The oligomerization chemistry was carried out using repetitive Horner-Wadsworth-Emmon

Full text of DOI:10.1021/jo501266g

Article
pubs.acs.org/joc
Controlled Regioregularity in Oligo(2-methoxy-5-(2′-ethylhexyloxy)-
1,4-phenylenevinylenes
Xinju Zhu and Kyle N. Plunkett*
Department of Chemistry and Biochemistry and the Materials Technology Center, Southern Illinois University, Carbondale, Illinois
62901, United States
S
* Supporting Information
ABSTRACT: A series of three pentameric derivatives of 2-methoxy-5-(2′-ethylhexyloxy)-p-phenylenevinylenes (2−4), with
varying degrees of side chain regioregularity, was prepared. The oligomerization chemistry was carried out using repetitive
Horner−Wadsworth−Emmons (HWE) reactions of precisely substituted aryl rings with four different substituents. The resulting
oligomers were characterized by nuclear magnetic resonance spectroscopy (NMR), cyclic voltammetry (CV) and absorption
1
spectroscopy in solution and in thin films. Each of the oligomers gave discrete H and 13C NMR spectra. The regioregular
pentamer (2) displayed the most resolution between signals and suggests those nuclei reside in more unique chemical
environments than the regiorandom pentamers (3 and 4). The solution phase electronic (CV) and absorption properties of each
of the new oligomers were found to be essentially identical. In contrast, the thin film absorption spectra were not equivalent. The
more regioregular pentamers (2 and 3) possessed a new, red-shifted shoulder structure that suggests the packing order is heavily
influenced by side chain regioregularity even at the pentamer level.
absorption and emission spectra to the isolated oligomer
counterparts. By varying the number of PPV repeat units from
3 to 5 to 7 at the prepolymerization stage, the spectral
properties, as well as the single-polymer chain anisotropies,
were systematically controlled.20 The short PPV oligomer-
containing polychromophores were disordered giving isotropic
structures, while the longer PPV oligomer-containing poly-
chromophores folded into highly anisotropic nanostructures
that are even more ordered than native poly[2-methoxy-5-(2′-
ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) polymers.15
Our recent goal is to probe the effects of chromophore side
chain regioregularity on polychromophore anisotropy. While
our former polychromophore studies utilized oligo-BEH-PPVs
that are symmetrically substituted with ethylhexyloxy side
chains (Figure 1, 1), traditional MEH-PPV27−29 monomers are
nonsymmetric (methoxy and ethylhexyloxy side chains) and
typically lead to regiorandom polymeric materials. Although
recent progress has led to regioregular MEH-PPV,30 this
polymer has yet to be investigated with single-polymer
techniques. Here we demonstrate the discrete chemical
synthesis of a series of three MEH-PPV pentamers (Figure 1,
2−4) with varying degrees of side chain regioregularity. We
have fully characterized the compounds via NMR spectroscopy
and find the more regioregular derivatives contain more
INTRODUCTION
■
The inherent regioregularity1−3 and composition4−11 of the
solubilizing side chains in conjugated polymers (CPs) has a
significant impact on that material’s performance in organic
electronic devices such as field-effect transistors, light emitting
diodes, and organic photovoltaics. Fine tuning of the interplay
between the aromatic core backbone and the aliphatic
hydrocarbon chains can lead to highly aligned polymeric
materials, which are known to facilitate charge transport, by
way of π−π overlap between neighboring polymer chains.4,12
While solubilizing chains on the polymer backbone are often
varied in length and in structure (e.g., straight vs branched),
these structural modifications are not always systematic, and the
ramifications of the changes are not always known at the
molecular level. However, recent advances in single-molecule
characterization techniques have provided opportunities to
probe how chemical structure can influence the conformations
of individual polymer chains.13−19
Using single-molecule techniques, we recently investigated
the impact of the conjugation length of individual chromo-
phores on their alignment in a single polymer chain.20 To
accomplish this task, we created polychromophore21−25
polymers composed of alternating conjugated oligomers of
bis(2-ethylhexyl)-p-phenylene-vinylenes (BEH-PPV) and satu-
rated flexible linkers of tetraethylene glycol.26 The maximum
effective conjugation length was controlled at the synthetic level
with the resulting polymers having nearly identical solution
Received: June 6, 2014
Published: July 8, 2014
© 2014 American Chemical Society
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are much more demanding owing to the unsymmetrical nature
of the side chains. The strategy relies on the ability to add
aldehyde and bromo functionality at exact locations around an
aryl ring (e.g., bromo ortho to methoxy; aldehyde ortho to
ethylhexyloxy). This specificity requires electronic manipulation
of the aryl ring during electrophilic additions.31 To address this
need, the electron rich 4-methoxyphenol (5) was tosylated to
form 6, which provides a compound with reduced electron-
density ortho to the tosyl group (Scheme 1). Bromination of 6
can then selectively proceed ortho to the electron rich methoxy
group to form 7. Deprotection of the tosylate group (8)
provides a system that can undergo formylation ortho to the
newly formed hydroxyl substituent to give 9. Protection of the
aldehyde (10), followed by Williamson ether synthesis with 2-
ethylhexyl bromide, creates the desired spatially arranged side
chains of 11. To access a building block capable of repetitive
HWE reactions, a series of transformations can convert the aryl
bromide 11 into phosphonate ester 15 that maintains a
protected aldehyde to be utilized for subsequent trans-
formations. Alternatively, bromide 11 can be converted to an
iodide 16 and then iodo-aldehyde 17 for oligomerization
chemistries. The orthogonal side chain functionalized deriva-
tives (29 and 34) were prepared from 4-ethylhexyloxyphenol
through an analogous reaction pathway (Scheme 2).
With the asymmetrically substituted monomers in hand,
access to the three pentamers of varying regioregularity was
relatively straightforward. For the completely regioregular
MEH-PPV example, 17 was used as an initiation point for
repetitive HWE couplings and deprotections with 15 to
produce dimer (35), trimer (36), tetramer (37), and finally
pentamer (2) (Scheme 3). It is important to note that after
each HWE reaction in this study, the crude mixture was
refluxed in toluene with catalytic iodine to ensure all vinyl
groups were in the more stable trans configuration. Access to
the semiregular pentamer 3 was accomplished by branching
away from the regioregular synthesis by combining 2 equiv of
dimer 35 with diphosphonate ester 18.18 The most
regiorandom (yet still an atomically defined material) pentamer
4 was accessed by coupling 17 with 29 to create dimer 38 that
has equivalent side chains on opposite sides of the ring system.
The combination of 2 equiv of 38 with diphosphonate 18 gave
pentamer 4. All coupling reactions proceeded in reasonable
Figure 1. MEH-PPV pentamers (2−4) of varying regioregularity.
BEH-PPV 1 was previously prepared.26 General 13C NMR assign-
ments provided (see Figure 2).
resolved signals. Furthermore, we have investigated the solution
and thin film UV−vis properties of each oligomer and
demonstrate the more regioregular oligomers adopt more
ordered aggregates in the solid state.
RESULTS AND DISCUSSION
■
Synthesis of Oligomers. Through a series of oligomeriza-
tion steps using the Horner−Wadsworth−Emmons (HWE)
reaction, we have synthesized MEH-PPV oligomers with
terminal iodo-functionality. The synthetic methodology for
this effort is a direct extension of our previous work;26 however,
the methods to create the well-defined MEH-PPV oligomers
Scheme 1. Route to Asymmetric Oligomer Building Blocks I
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Scheme 2. Route to Asymmetric Oligomer Building Blocks II
Scheme 3. Step-Wise Oligomerization Strategy
yields (36−68%) following iodine reflux and acetal depro-
tection steps.
Oligomer Characterization. Significant overlap in the
aromatic region (especially due to ABq splitting of vinylic
protons) of the 1H NMR spectra limits the ability to
unambiguously assign specific proton resonances. However,
integration of the aryl and vinylic protons clearly demonstrated
the desirable quantities in each region. Moreover, a qualitative
evaluation of the spectra (Supporting Information) shows the
regioregular pentamer 2 provided more chemically resolved
signals (8 aryl singlets, with two overlapping, for 10 protons)
than the more regiorandom pentamers 3 and 4 (5 aryl singlets
for 10 protons). These data suggest the regioregular protons
reside in more distinctive chemical environments than the
regiorandom protons. The aromatic and vinylic signals were
significantly more resolved in the 13C NMR spectra in all cases
(Figure 2). Each of the 38 individual aromatic and vinylic
carbon atoms gave resolved signals32 that varied in chemical
shift for each derivative. The general assignments for the
carbons can be found in Figure 1. Overall, there were five
regions where the signals were found. Two of the regions
containing 10 resonances each, which are assigned to the aryl
carbons bound to oxygen (150.0−152.0 ppm, b) and aryl
carbons bound to hydrogen (121.0−123.0 ppm, c). Two other
signal regions contain the vinylic carbons (126.0−128.0 ppm,
e) and eight aryl carbons bound to the vinyl groups (107.0−
111.0 ppm, d). Finally, one region contained the two carbons
Figure 2. 13C NMR spectra for PPV oligomers 1−4. Each set of
signals can be assigned to either a carbon on the aryl rings or vinylic
bonds.
bound to iodides (84.0−86.0 ppm, a). Each of the new MEH-
PPV oligomers show more complex spectra than the BEH-PPV
pentamer 1 (Figure 2, top) that has half the number of the
signals owing to the full symmetry of the compound.
Comparison of the two regioregular examples shows that the
signals are essentially split into two (e.g., vinylic carbons 126.0−
128.0 ppm) going from BEH-pentamer 1 to MEH-pentamer 2.
The electronic and photophysical properties of each of the
new oligomers were characterized by cyclic voltammetry and
UV−vis spectroscopy. As expected, for a chromophore with the
exact same pi-conjugated system, the electrochemistry of each
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oligomer is essentially the same (Figure 3). The oxidation wave
onsets were measured to be 0.24, 0.25, and 0.23 V (vs ferrocene
Figure 5. Absorbance of MEH-PPV oligomers 2, 3, and 4 in thin film
after annealing at 100 °C for 45 min.
Figure 3. Cyclic voltammograms of 2, 3, and 4 in chloroform with 0.1
M tetrabutylammonium hexafluorophosphate, platinum counter
electrode, and an Ag/AgCl reference electrode. Scan rate = 50 mV/
s. Ferrocene added as internal standard and referenced to 0 V.
constant. However, the two more regioregular pentamers 2 and
3 show different peak shapes and possess a new red-shifted,
shoulder structure. The relative definition of the shoulder is
greater in 2 than in 3 and appears to be directly related to the
regioregularity of the side chains. Similar presence and absence
of low-energy shoulders are known in conjugated polymers and
often depend on the degree of regioregularity.33−35 These
shoulder structures have been assigned to new π−π* transitions
that are associated with interchain absorption in materials such
as MEH-PPV36,37 and poly(3-hexylthiophene)34 with the
intensity of the shoulder correlating with the degree of order
in the film. The melting points (mp) of each oligomer was also
dramatically affected by the substitution pattern with the mp
decreasing stepwise going from regioregular 2 to regiorandom
4 (Table 1). Although only preliminary, these results show that
even at the MEH-PPVs pentamer level, the role of side chain
order is important for creating more ordered materials in the
solid state.
In conclusion, we have demonstrated the discrete synthesis
and characterization of three MEH-PPV pentamers with a
range of side chain regioregularity. We are currently
investigating the solid state packing, as well as the single
molecule and small-aggregate fluorescence, of these materials in
more detail. With these new materials in hand we will also
probe the effects of regioregularity on the anisotropies of
polychromophore structures.
Table 1. Physical Properties of Pentamers
λabs,max,sol
(nm)
λabs,max,film
(nm)
λonset,film
(nm)
Eox,onset
a
mp
(°C)
pentamer
(V)
2
3
4
464
464
463
458
471
467
565
568
540
0.24
0.25
0.23
176
158
106
a
Potential relative to ferrocenium/ferrocene redox couple.
at 0 V) for 2, 3, and 4 respectively (Table 1). No low lying
reduction waves are observed. These results confirm the
regioregularity of the side chains does not significantly affect
the solution phase electrochemistry of these similarly
conjugated compounds.
The solution phase UV−vis gives identical absorption spectra
for all three pentamers with the λmax ∼ 464 nm (Figure 4).
EXPERIMENTAL SECTION
■
Unless otherwise noted, all reagents were used as received, and all
reactions were carried out under an argon atmosphere. Column
chromatography was performed on a chromatographing system with
1
normal phase silica columns. H NMR and 13C NMR were recorded
on a 400 MHz NMR station at room temperature, unless otherwise
noted. Cyclic voltammetry was performed on a potentiostat with a 0.1
M tetrabutylammonium hexafluorophosphate solution (Chloroform)
using a glassy carbon electrode, platinum counter electrode, and an
Ag/AgCl reference electrode.
Figure 4. Absorbance of MEH-PPV oligomers 2, 3, and 4 in toluene.
4-Methoxyphenyl 4-methylbenzenesulfonate (6). In a 500
mL round-bottom flask was added 4-methoxy-phenol 5 (25.0 g, 201.4
mmol), TsCl (38.3 g, 201.4 mmol) in 250 mL of THF. Then, Et3N
(42 mL, 301.5 mmol) was added slowly. The mixture was stirred at
room temperature overnight. CH2Cl2 (200 mL) was added and the
mixture was extracted with water (2 × 50 mL) and brine (50 mL). The
organic layer was dried over MgSO4 and concentrated. The residue
was crystallized using MeOH to give 47.7 g (85.1%) white needle
Complementary to the electrochemistry, these results demon-
strate that pentamers 2, 3, and 4 are photochemically
equivalent in solution. However, the similarities in their
electronic structure diverge when in the solid state. The thin
film absorption spectra obtained after spin coating and thermal
annealing are not equivalent for the three oligomers (Figure 5).
While the spectrum of the regiorandom pentamer 4 broadens
in comparison to the solution, the peak shape remains relatively
1
solid: H NMR (400 MHz, CDCl3) δ 7.71−7.65 (m, 2H), 7.32−7.27
(m, 2H), 6.90−6.84 (m, 2H), 6.79−6.72 (m, 2H), 3.76 (s, 3H), 2.44
(s, 3H); 13C NMR (101 MHz, CDCl3) δ 158.2, 145.2, 143.1, 132.3,
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129.7, 128.6, 123.3, 114.4, 55.5, 21.7. Proton and Carbon NMR match
previous report.31
was purified by silica gel chromatography (0−35% CH2Cl2 in hexane)
to give 11.88 g (95.4%) light yellow oil: 1H NMR (400 MHz, CDCl3)
δ 7.22 (s, 1H), 7.08 (s, 1H), 5.68 (s, 1H), 3.88 (s, 3H), 3.81 (d, J = 5.5
Hz, 2H), 3.75 (d, J = 11.0 Hz, 2H), 3.63 (d, J = 11.1 Hz, 2H), 1.76−
1.66 (m, 1H), 1.52−1.37 (m, 4H), 1.37−1.23 (m, 7H), 0.96−0.84 (m,
6H), 0.79 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 150.7, 150.1,
127.0, 117.5, 112.2, 110.8, 96.7, 77.9, 71.7, 56.8, 39.5, 30.7, 30.3, 29.1,
24.0, 23.2, 23.1, 21.8, 14.1, 11.2; LRMS (ES+ + H) 429.2; HRMS
(TOF MS ES+) m/z for C21H34O4Br calcd 429.1640, found 429.1648.
4-(5,5-Dimethyl-1,3-dioxan-2-yl)-5-((2-ethylhexyl)oxy)-2-
methoxy-benzaldehyde (12). In a glovebox were added 11 (1.05 g,
2.45 mmol) in THF (50 mL) in a 100 mL two neck round bottle flask.
The solution was taken out of glovebox and cooled down to −78 °C
under Ar. A solution of n-BuLi (3.18 mmol, 2.0 mL) in hexane was
added dropwise and stirred at −78 °C for 1 h. Then DMF (2 mL) was
added to the mixture and stirred for another 2 h and temperature was
allowed to increase to room temperature. H2O (20 mL) was added to
quench the reaction. CH2Cl2 (100 mL) was added, and the mixture
was extracted with water (2 × 50 mL) and brine (50 mL). The organic
layer was dried over MgSO4 and concentrated. The residue was
purified by silica gel chromatography (0−60% CH2Cl2 in hexane) to
3-Bromo-4-methoxyphenyl 4-methylbenzenesulfonate (7).
In a 250 mL round bottle flask was stirred a mixture of 6 (15.5 g, 55.7
mmol), KOAc (12.0 g, 122.5 mmol) in acetic acid (150 mL). Br2 (10.7
g, 66.8 mmol, 3.5 mL) was then added. The mixture was stirred at 50
°C overnight. After that, more Br2 (0.12 equiv) was added and allowed
to react for another 12 h. The reaction was cooled at room
temperature, and NaHSO3 was added until the color of Br2
disappeared. CH2Cl2 (200 mL) was added, and the mixture was
extracted with water (2 × 50 mL) and brine (50 mL). The organic
layer was dried over MgSO4 and concentrated. The residue was pure
1
enough to be used for next reaction without further purification: H
NMR (400 MHz, CDCl3) δ 7.72−7.67 (m, 2H), 7.35−7.30 (m, 2H),
7.15 (d, J = 2.8 Hz, 1H), 6.93 (dd, J = 9.0, 2.8 Hz, 1H), 6.79−6.75 (m,
1H), 3.86 (s, 3H), 2.46 (s, 3H); 13C NMR (101 MHz, CDCl3) δ
154.8, 145.6, 142.8, 132.0, 129.8, 128.5, 127.4, 122.3, 111.6, 111.4,
56.5, 21.7.
3-Bromo-4-methoxy-phenol (8). In a 250 mL round bottle flask
wad added 7 from last step in tBuOH (40 mL). A solution of 20%
aqueous NaOH (40 mL) was added. The mixture was reflux overnight.
The reaction mixture was cooled and neutralized with 1 M HCl.
CH2Cl2 (200 mL) was added, and the mixture was extracted with
water (2 × 50 mL) and brine (50 mL). The organic layer was dried
over Na2SO4 and concentrated. The residue was purified by silica gel
chromatography (0−70% CH2Cl2 in hexane) to give 10.3 g (91.2%,
two steps) white solid: 1H NMR (400 MHz, CDCl3) δ 7.08 (d, J = 2.7
Hz, 1H), 6.81−6.74 (m, 2H), 4.62 (s, 1H), 3.83 (d, J = 2.8 Hz, 3H);
13C NMR (101 MHz, CDCl3) δ 150.3, 149.8, 120.5, 115.0, 113.2,
112.0, 57.0; LRMS (EI+) 202.0; HRMS (TOF MS EI+) m/z for
C7H7O2Br calcd 201.9629, found 201.9627. Proton and Carbon NMR
match previous report.38
4-Bromo-2-hydroxy-5-methoxy-benzaldehyde (9). In a 250
mL round bottle flask was added MgCl2 (7.24 g, 76.1 mmol) and dry
Et3N (27 mL, 192.6 mmol) into a solution of 8 (10.3 g, 50.3 mmol) in
150 mL of dry CH3CN. Then paraformaldehyde (10.6 g, 354.9 mmol)
was added. The reaction mixture was reflux overnight and cooled
down to room temperature. After that, the mixture was poured into 1
M HCl to neutralize. CH2Cl2 (200 mL) was added, and the mixture
was extracted with water (2 × 50 mL) and brine (50 mL). The organic
layer was dried over Na2SO4 and concentrated. The residue was
purified by silica gel chromatography (0−40% CH2Cl2 in hexane) to
give 5.82 g (49.7%) bright yellow solid: 1H NMR (400 MHz, CDCl3)
δ 10.72 (s, 1H), 9.84 (s, 1H), 7.27 (s, 1H), 6.98 (s, 1H), 3.90 (s, 3H);
13C NMR (101 MHz, CDCl3) δ 195.4, 155.9, 149.6, 123.0, 122.9,
1
give 0.63 g (68%) light yellow oil: H NMR (400 MHz, CDCl3) δ
10.44 (s, 1H), 7.32 (s, 1H), 7.31 (s, 1H), 5.72 (s, 1H), 3.93 (s, 3H),
3.88 (d, J = 5.6 Hz, 2H), 3.77 (d, J = 11.2 Hz, 2H), 3.65 (d, J = 11.2
Hz, 2H), 1.77−1.65 (m, 1H), 1.52−1.37 (s, 4H), 1.37−1.29 (m, 7H),
0.96−0.88 (m, 6H), 0.80 (s, 3H); 13C NMR (101 MHz, CDCl3) δ
189.5, 156.5, 150.4, 134.5, 125.0, 110.9, 110.1, 96.5, 77.9, 71.3, 56.1,
39.4, 30.7, 30.3, 29.0, 24.1, 23.2, 23.1, 21.8, 14.1, 11.2; LRMS (ES+ +
H) 379.2; HRMS (TOF MS ES+) m/z for C22H35O5 calcd 379.2484,
found 379.2477.
[4-(5,5-Dimethyl-1,3-dioxan-2-yl)-5-((2-ethylhexyl)oxy)-2-
methoxy-phenyl] methanol (13). In a 100 mL two-necked round-
bottom flask was stirred 12 (1.30 g, 3.43 mol) in THF (30 mL) at 0
°C for 10 min. NaBH4 (156 mg, 4.12 mmol) was carefully added, and
the mixture was stirred overnight. Methanol was added to quench the
NaBH4. CH2Cl2 (100 mL) was added, and the mixture was extracted
with water (2 × 50 mL) and brine (50 mL). The organic layer was
dried over MgSO4 and concentrated to give colorless oil without
further purification: 1H NMR (400 MHz, CDCl3) δ 7.18 (s, 1H), 6.86
(s, 1H), 5.74 (s, 1H), 4.65 (d, J = 6.5 Hz, 2H), 3.86 (s, 3H), 3.84 (d, J
= 5.6 Hz, 2H), 3.75 (d, J = 11.1 Hz, 2H), 3.64 (d, J = 11.0 Hz, 2H),
2.25 (t, J = 6.5 Hz, 1H), 1.75−1.68 (m, 1H), 1.53−1.39 (m, 4H),
1.37−1.28 (m, 7H), 0.96−0.89 (s, 6H), 0.80 (s, 3H); 13C NMR (101
MHz, CDCl3) δ 151.0, 150.3, 130.6, 126.4, 112.9, 108.7, 97.0, 77.9,
71.6, 61.6, 55.7, 39.6, 30.7, 30.3, 29.1, 24.0, 23.2, 23.1, 21.9, 14.1, 11.2.
2-[4-Bromomethyl-2-((2-ethylhexyl)oxy)-5-methoxy-phe-
nyl]-5,5-dimethyl-1,3-dioxane (14). In a 100 mL two-necked
round-bottom flask was stirred 13 (1.31 g, 3.45 mmol) in THF (50
mL) at 0 °C for 10 min. Carbon tetrabromide (1.48 g, 4.49 mmol) and
triphenyl-phosphine (1.18 g, 4.49 mmol) was added, and the mixture
was stirred overnight. CH2Cl2 (100 mL) was added, and the mixture
was extracted with water (2 × 50 mL) and brine (50 mL). The organic
layer was dried over MgSO4 and concentrated. The residue was
purified by silica gel chromatography (0 → 20% CH2Cl2 in hexane, Rf
119.3, 113.9, 56.9. Proton and Carbon NMR match previous report.39
5-Bromo-2-(5,5-dimethyl-1,3-dioxan-2-yl)-4-methoxy-phe-
nol (10). In a 250 mL round-bottom flask with a dean-stark trap were
added 9 (4.25 g, 18.3 mmol), 2,2-dimethylpropane-1,3-diol (7.62 g,
73.2 mmol) and catalytic amount (1%) of p-TsOH (35.2 mg, 0.18
mmol) in toluene (100 mL). The mixture was reflux overnight and
then cooled to room temperature. CH2Cl2 (100 mL) was added, and
the mixture was extracted with water (2 × 50 mL) and brine (50 mL).
The organic layer was dried over Na2SO4 and concentrated. The
residue was purified by silica gel chromatography (0−40% CH2Cl2 in
1
= 0.4) to give 0.77 g (50.3%, two steps) as a yellowish oil: H NMR
1
(400 MHz, CDCl3) δ 7.19 (s, 1H), 6.86 (s, 1H), 5.71 (s, 1H), 4.53 (s,
2H), 3.88 (s, 3H), 3.83 (d, J = 5.6 Hz, 2H), 3.75 (d, J = 11.1 Hz, 2H),
3.63 (d, J = 11.0 Hz, 2H), 1.76−1.68 (s, 1H), 1.53−1.39 (m, 4H),
1.38−1.28 (m, 7H), 0.97−0.88 (m, 6H), 0.80 (s, 3H); 13C NMR (101
MHz, CDCl3) δ 151.6, 150.2, 128.4, 127.1, 114.9, 109.9, 96.9, 77.9,
71.6, 56.2, 39.6, 30.7, 30.3, 29.1, 28.9, 24.1, 23.2, 23.1, 21.9, 14.1, 11.2.
Diethyl 4-(5,5-dimethyl-1,3-dioxan-2-yl)-5-((2-ethylhexyl)-
oxy)-2-methoxy-benzyl-phosphonate (15). In a 20 mL vial was
added 14 (770 mg, 0.96 mmol) and triethyl phosphite (404 mg, 2.44
mmol). The mixture was heated in 140 °C for 2 h and then cooled to
room temperature. The residue was directly purified by silica gel
chromatography (0 → 33% EtOAc in hexane, Rf = 0.4) to give 810 mg
(93%) as a yellowish oil: 1H NMR (400 MHz, CDCl3) δ 7.15 (s, 1H),
6.91 (d, J = 2.7 Hz, 1H), 5.71 (s, 1H), 4.05−3.96 (m, 4H), 3.84−3.80
(m, 5H), 3.75 (d, J = 11.2 Hz, 2H), 3.63 (d, J = 10.7 Hz, 2H), 3.21 (d,
hexane) to give 4.34 g (74.8%) light yellow oil: H NMR (400 MHz,
CDCl3) δ 7.65 (s, 1H), 7.12 (s, 1H), 6.77 (s, 1H), 5.50 (s, 1H), 3.84−
3.79 (m, 5H), 3.69−3.64 (m, 2H), 1.28 (s, 3H), 0.83 (s, 3H); 13C
NMR (101 MHz, CDCl3) δ 149.4, 149.3, 122.0, 121.3, 113.0, 111.2,
102.0, 77.5, 56.9, 30.4, 22.9, 21.8; LRMS (EI+) 316.0; HRMS (TOF
MS EI+) m/z for C13H17O4Br calcd 316.0310, found 316.0309.
2-[4-Bromo-2-((2-ethylhexyl)oxy)-5-methoxy-phenyl]-5,5-di-
methyl-1,3-dioxane (11). In a 250 mL round-bottom flask was
stirred 10 (9.2 g, 29.0 mmol) in DMSO (100 mL) under argon. After
fully deoxygenated, KOH power (4.1 g, 72.5 mmol) was added. Then,
2-ethylhexyl bromide (11.2 g, 58.0 mmol) was added slowly. The
mixture was stirred at 50 °C overnight. The reaction mixture was
neutralized with 1 M HCl. Diethyl ether (200 mL) was added, and the
mixture was extracted with water (2 × 50 mL) and brine (50 mL). The
organic layer was dried over MgSO4 and concentrated. The residue
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J = 21.9 Hz, 2H), 1.74−1.66 (m, 1H), 1.54−1.37 (m, 4H), 1.36−1.28
(m, 7H), 1.23 (t, J = 7.1 Hz, 6H), 0.95−0.88 (m, 6H), 0.79 (s, 3H);
13C NMR (101 MHz, CDCl3) δ 151.3, 151.2, 150.1, 150.0, 126.2,
126.2, 121.5, 121.4, 115.6, 115.6, 109.2, 109.2, 97.1, 97.1, 77.9, 71.5,
61.9, 61.8, 56.1, 39.6, 30.7, 30.3, 29.1, 27.2, 25.8, 24.0, 23.2, 23.1, 21.9,
16.4, 16.3, 14.1, 11.2; LRMS (ES+ + H) 501.3; HRMS (TOF MS ES
+) m/z for C26H46O7P calcd 501.2981, found 501.2980.
(0−10% EtOAc in hexane) to give 5.73 g (35.5%) light yellow oil: 1H
NMR (400 MHz, CDCl3) δ 6.81−6.72 (m, 4H), 4.42 (s, 1H), 3.81−
3.74 (m, 2H), 1.69 (dt, J = 12.2, 6.1 Hz, 1H), 1.55−1.36 (m, 4H),
1.34−1.27 (m, 4H), 0.95−0.86 (m, 6H); 13C NMR (101 MHz,
CDCl3) δ 153.7, 149.2, 115.9, 115.6, 71.3, 39.4, 30.5, 29.1, 23.8, 23.0,
14.1, 11.1. Proton and Carbon NMR match previous report.40
4-((2-Ethylhexyl)oxy)phenyl 4-methylbenzenesulfonate
(20). In a 250 mL round-bottom flask was added 19 (8.90 g, 40.03
mmol), TsCl (7.63 g, 40.03 mmol) in 150 mL of THF. Then, Et3N
(8.4 mL, 60.05 mmol) was added slowly. The mixture was stirred at
room temperature overnight. CH2Cl2 (200 mL) was added, and the
mixture was extracted with water (2 × 50 mL) and brine (50 mL). The
organic layer was dried over MgSO4 and concentrated. The residue
was purified by silica gel chromatography (0−60% CH2Cl2 in hexane)
2-[2-((2-Ethylhexyl)oxy)-4-iodo-5-methoxyphenyl]-5,5-di-
methyl-1,3-dioxane (16). In a glovebox were added 11 (1.00 g, 2.33
mmol) in THF (50 mL) in a 100 mL two neck round bottle flask. The
solution was taken out of glovebox and cooled down to −78 °C under
Ar. A solution of n-BuLi (3.03 mmol, 1.9 mL) in hexane was added
dropwise and stirred at −78 °C for 1 h. Then I2 (0.768 g, 3.03 mmol)
of THF solution was added to the mixture and stirred for another 2 h
and temperature was allowed to increase to room temperature. H2O
(20 mL) was added to quench the reaction. CH2Cl2 (100 mL) was
added, and the mixture was extracted with water (2 × 50 mL) and
brine (50 mL). The organic layer was dried over MgSO4 and
concentrated. The residue was purified by silica gel chromatography
1
to give 14 g (93%) of colorless oil: H NMR (400 MHz, CDCl3) δ
7.72−7.66 (m, 2H), 7.32−7.28 (m, 2H), 6.88−6.83 (m, 2H), 6.78−
6.73 (m, 2H), 3.79−3.74 (m, 2H), 2.45 (s, 3H), 1.72−1.65 (m, 1H),
1.51−1.36 (m, 4H), 1.35−1.26 (m, 4H), 0.94−0.87 (m, 6H); 13C
NMR (101 MHz, CDCl3) δ 158.0, 145.1, 142.8, 132.4, 129.7, 128.6,
123.2, 115.0, 70.9, 39.3, 30.5, 29.0, 23.8, 23.0, 21.7, 14.1, 11.1; LRMS
(ES+ + H) 377.2; HRMS (TOF MS ES+) m/z for C21H29O4S calcd
377.1787, found 377.1785.
1
(0−35% CH2Cl2 in hexane) to give 598 mg (53.9%) colorless oil: H
NMR (400 MHz, CDCl3) δ 7.27 (s, 1H), 7.13 (s, 1H), 5.67 (s, 1H),
3.87 (s, 3H), 3.80 (d, J = 5.5 Hz, 2H), 3.74 (d, J = 11.2 Hz, 2H), 3.63
(d, J = 10.6 Hz, 2H), 1.75−1.66 (m, 1H), 1.53−1.37 (m, 4H), 1.36−
1.28 (m, 7H), 0.96−0.88 (m, 6H), 0.79 (s, 3H).13C NMR (101 MHz,
CDCl3) δ 152.6, 150.9, 128.1, 123.4, 109.4, 96.8, 86.4, 77.8, 71.7, 57.0,
39.5, 30.7, 30.3, 29.1, 24.0, 23.2, 23.1, 21.8, 14.1, 11.2; LRMS (ES+ +
H) 477.1; HRMS (TOF MS ES+) m/z for C21H34O4I calcd 477.1502,
found 477.1495.
3-Bromo-4-((2-ethyl-hexyl)oxy)phenyl 4-methylbenzenesul-
fonate (21). In a 250 mL round bottle flask was stirred a mixture of
20 (16.0 g, 42.5 mmol), KOAc (9.2 g, 93.5 mmol) in acetic acid (150
mL). Br2 (8.2 g, 51.0 mmol, 2.6 mL) was then added. The mixture was
stirred at 50 °C overnight. After that, more Br2 (0.12 equiv) was added
and allowed to react for another 12 h. The reaction was cooled at
room temperature and NaHSO3 was added until the color of Br2
disappeared. CH2Cl2 (200 mL) was added, and the mixture was
extracted with water (2 × 50 mL) and brine (50 mL). The organic
layer was dried over MgSO4 and concentrated. The residue was pure
2-((2-Ethylhexyl)oxy)-4-iodo-5-methoxy-benzaldehyde (17).
16 (1.05 g, 2.20 mmol) was dissolved in a solution of trifluoroacetic
acid (2 mL), THF (10 mL) and H2O (2 mL) in 100 mL round-
bottom flask and stirred at 50 °C overnight. CH2Cl2 (100 mL) was
added, and the mixture was extracted with water (2 × 50 mL) and
brine (50 mL). The organic layer was dried over MgSO4 and
concentrated. The residue was purified by silica gel chromatography (0
→ 40% CH2Cl2 in hexane, Rf = 0.4) to give 850 mg (98.8%) as a
bright yellow solid: 1H NMR (400 MHz, CDCl3) δ 10.43 (s, 1H), 7.47
(s, 1H), 7.22 (s, 1H), 3.94−3.89 (m, 2H), 3.87 (s, 3H), 1.81−1.72 (m,
1H), 1.52−1.39 (m, 4H), 1.37−1.28 (m, 4H), 0.98−0.88 (m, 6H); 13C
NMR (101 MHz, CDCl3) δ 189.1, 156.1, 152.5, 125.1, 124.5, 107.7,
96.0, 71.6, 56.9, 39.4, 30.6, 29.0, 23.9, 23.0, 14.1, 11.2; LRMS (ES+
+H) 391.1; HRMS (TOF MS ES+) m/z for C16H24O3I calcd
391.0770, found 391.0772.
Tetraethyl-2-((2-ethylhexyl)oxy)-5-methoxy-1,4-phenylene-
bis(methylene)-bis(phosphonate) (18). In a 20 mL vial was added
1,4-bis(bromomethyl)-2-((2-ethylhexyl)oxy)-5-methoxybenzene (454
mg, 1.07 mmol) and triethyl phosphite (446 mg, 2.68 mmol). The
mixture was heated in 140 °C for 2 h and then cooled to room
temperature. The residue was directly purified by silica gel
chromatography (0 → 66% EtOAc in hexane) to give 73 mg (82%)
as a yellowish oil: 1H NMR (400 MHz, CDCl3) δ 6.94 (s, 1H), 6.89 (s,
1H), 4.07−3.95 (m, 8H), 3.82−3.78 (m, 5H), 3.22 (dd, J = 20.5, 7.0
Hz, 4H), 1.74−1.66 (m, 1H), 1.56−1.36 (m, 4H), 1.34−1.28 (m, 4H),
1.23 (td, J = 7.1, 4.4 Hz, 12H), 0.94−0.87 (m, 6H); 13C NMR (101
MHz, CDCl3) δ 150.8, 150.8, 150.8, 150.7, 150.6, 150.6, 150.6, 150.5,
119.5, 119.4, 119.4, 119.3, 119.3, 119.3, 119.2, 119.2, 114.79, 114.77,
114.74, 114.7, 113.9, 113.90, 113.88, 113.85, 71.1, 61.89, 61.86, 61.83,
61.8, 56.1, 39.6, 30.6, 29.1, 23.9, 23.0, 16.4, 16.3, 16.3, 16.3, 14.0, 11.1;
LRMS (ES+ + H) 537.3; HRMS (TOF MS ES+) m/z for C25H47O8P2
calcd 537.2746, found 537.2743. Proton and Carbon NMR match
previous report.18
1
enough to be used for next reaction without further purification: H
NMR (400 MHz, CDCl3) δ 7.73−7.67 (m, 2H), 7.35−7.30 (m, 2H),
7.13 (d, J = 2.8 Hz, 1H), 6.89 (dd, J = 8.9, 2.8 Hz, 1H), 6.74 (d, J = 9.0
Hz, 1H), 3.84 (d, J = 5.5 Hz, 2H), 2.46 (s, 3H), 1.75 (dt, J = 12.2, 6.0
Hz, 1H), 1.54−1.39 (m, 4H), 1.35−1.27 (m, 4H), 0.96−0.85 (m, 6H);
13C NMR (101 MHz, CDCl3) δ 154.6, 145.5, 142.5, 132.0, 129.8,
128.6, 127.2, 122.2, 112.4, 111.9, 71.8, 39.3, 30.4, 29.0, 23.8, 23.0, 21.7,
14.1, 11.2.
3-Bromo-4-((2-ethyl-hexyl)oxy)phenol (22). In a 250 mL
round bottle flask was added 21 from last step in tBuOH (60 mL).
A solution of 20% aqueous NaOH (60 mL) was added. The mixture
was heated at reflux overnight. The reaction mixture was cooled and
neutralized with 1 M HCl. CH2Cl2 (200 mL) was added, and the
mixture was extracted with water (2 × 50 mL) and brine (50 mL). The
organic layer was dried over Na2SO4 and concentrated. The residue
was purified by silica gel chromatography (0−70% CH2Cl2 in hexane)
1
to give 9.51 g (74.3%, two steps) colorless oil: H NMR (400 MHz,
CDCl3) δ 7.06 (d, J = 2.8 Hz, 1H), 6.78 (d, J = 8.8 Hz, 1H), 6.73 (dd,
J = 8.8, 2.8 Hz, 1H), 4.44 (s, 1H), 3.83 (d, J = 5.6 Hz, 2H), 1.74 (dt, J
= 12.2, 6.1 Hz, 1H), 1.60−1.39 (m, 4H), 1.36−1.28 (m, 4H), 0.96−
0.87 (m, 6H); 13C NMR (101 MHz, CDCl3) δ 150.1, 149.5, 120.5,
115.1, 114.8, 112.8, 72.7, 39.4, 30.4, 29.1, 23.8, 23.1, 14.1, 11.2; LRMS
(EI+) 300.1; HRMS (TOF MS EI+) m/z for C14H21O2Br calcd
300.0725, found 300.0726.
4-Bromo-5-((2-ethylhexyl)oxy)-2-hydroxy-benzaldehyde
(23). In a 250 mL round bottle flask was added MgCl2 (4.51 g, 47.4
mmol) and dry Et3N (16 mL, 120 mmol) into a solution of 22 (9.51 g,
31.6 mmol) in 150 mL of dry CH3CN. Then paraformaldehyde (6.64
g, 221.2 mmol) was added. The reaction mixture was heated under
reflux overnight and cooled down to room temperature. After that, the
mixture was poured into 1 M HCl to neutralize. CH2Cl2 (150 mL) was
added, and the mixture was extracted with water (2 × 50 mL) and
brine (50 mL). The organic layer was dried over Na2SO4 and
concentrated. The residue was purified by silica gel chromatography
(0−40% CH2Cl2 in hexane) to give 5.23 g (50.3%) light yellow oil: 1H
NMR (400 MHz, CD2Cl2) δ 10.71 (s, 1H), 9.85 (d, J = 0.6 Hz, 1H),
7.26 (s, 1H), 7.04 (s, 1H), 3.92 (d, J = 5.6 Hz, 2H), 1.79 (dt, J = 12.1,
5.9 Hz, 1H), 1.62−1.44 (m, 4H), 1.39−1.32 (m, 4H), 1.00−0.90 (m,
4-((2-Ethylhexyl)oxy)phenol (19). In a 250 mL round-bottom
flask was stirred hydro-quinone (8 g, 72.6 mmol) in 100 mL of DMSO
under argon. After fully deoxygenated, KOH power (8.2 g, 145.2
mmol) was added. Then, 2-ethylhexyl bromide (14.0 g, 72.6 mmol)
was added slowly. The mixture was stirred at 50 °C overnight. The
reaction mixture was neutralized with 1 M HCl. Diethyl ether (200
mL) was added, and the mixture was extracted with water (2 × 50
mL) and brine (50 mL). The organic layer was dried over Na2SO4 and
concentrated. The residue was purified by silica gel chromatography
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6H); 13C NMR (101 MHz, CDCl3) δ 195.4, 155.7, 149.4, 123.7,
122.7, 119.3, 114.9, 72.3, 39.4, 30.5, 29.0, 23.9, 23.0, 14.1, 11.2; LRMS
(ES+ + H) 331.1; HRMS (TOF MS ES+) m/z for C15H22O3Br calcd
329.0752, found 329.0747.
1H), 1.75−1.67 (m, 1H), 1.52−1.38 (m, 4H), 1.35−1.28 (m, 7H),
0.95−0.87 (m, 6H), 0.79 (s, 3H); 13C NMR (101 MHz, CDCl3) δ
150.9, 150.3, 130.7, 126.1, 111.8, 109.5, 96.8, 77.9, 70.4, 62.1, 56.5,
39.5, 30.8, 30.3, 29.1, 24.2, 23.2, 23.0, 21.9, 14.1, 11.3.
5-Bromo-2-(5,5-dimethyl-1,3-dioxan-2-yl)-4-((2-ethylhexyl)-
oxy)-phenol (24). In a 250 mL round-bottom flask with a dean-stark
trap were added 23 (5.23 g, 15.9 mmol), 2,2-dimethylpropane-1,3-diol
(6.62 g, 63.6 mmol) and catalytic amount (1%) of p-TsOH (30.2 mg,
0.16 mmol) in toluene (100 mL). The mixture was reflux overnight
and then cooled to room temperature. CH2Cl2 (150 mL) was added,
and the mixture was extracted with water (2 × 50 mL) and brine (50
mL). The organic layer was dried over Na2SO4 and concentrated. The
residue was purified by silica gel chromatography (0−40% CH2Cl2 in
2-[4-Bromomethyl-5-((2-ethylhexyl)oxy)-2-methoxy-phe-
nyl]-5,5-dimethyl-1,3-dioxane (28). In a 100 mL two-necked
round-bottom flask was stirred 27 (1.2 g, 3.15 mmol) in THF (50 mL)
at 0 °C for 10 min. Carbon tetrabromide (1.36 g, 4.1 mmol) and
triphenylphosphine (1.08 g, 4.1 mmol) was added, and the mixture
was stirred overnight. CH2Cl2 (100 mL) was added, and the mixture
was extracted with water (2 × 50 mL) and brine (50 mL). The organic
layer was dried over MgSO4 and concentrated. The residue was
purified by silica gel chromatography (0 → 20% CH2Cl2 in hexane, Rf
1
1
= 0.4) to give 0.89 g (63.8%, two steps) as a yellowish oil: H NMR
hexane) to give 4.93 g (74.7%) light yellow oil: H NMR (400 MHz,
(400 MHz, CDCl3) δ 7.16 (s, 1H), 6.86 (s, 1H), 5.73 (s, 1H), 4.53 (s,
2H), 3.93 (d, J = 5.2 Hz, 2H), 3.80 (a, 3H), 3.78−3.74 (d, J = 11.0 Hz,
3H), 3.67 (d, J = 10.6 Hz, 3H), 1.77−1.70 (m, 1H), 1.59−1.44 (m,
4H), 1.38−1.26 (m, 7H), 0.97−0.87 (m, 6H), 0.79 (s, 3H); 13C NMR
(101 MHz, CDCl3) δ 151.4, 150.0, 128.0, 127.2, 113.8, 110.3, 96.7,
77.9, 70.4, 56.5, 39.6, 30.7, 30.3, 29.2, 28.9, 24.1, 23.2, 23.1, 21.9, 14.1,
11.3.
CDCl3) δ 7.63 (s, 1H), 7.11 (s, 1H), 6.74 (s, 1H), 5.49 (s, 1H), 3.85−
3.79 (m, 5H), 3.67 (d, J = 10.6 Hz, 2H), 1.77−1.68 (m, 1H), 1.60−
1.39 (m, 4H), 1.37−1.27 (m, 4H), 1.28 (s, 3H), 0.96−0.88 (m, 6H),
0.83 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 149.2, 149.1, 121.9,
121.2, 113.8, 112.3, 102.1, 77.6, 72.2, 39.5, 30.5, 30.4, 29.1, 23.9, 23.0,
23.0, 21.8, 14.1, 11.2; LRMS (ES+ + H) 415.1.
4-Bromo-2-[5-((2-ethylhexyl)oxy)-2-methoxy-phenyl]-5,5-di-
methyl-1,3-dioxane (25). In a 250 mL round-bottom flask was
stirred 24 (4.93 g, 11.9 mmol) in 100 mL of DMSO under argon.
After fully deoxygenated, KOH power (3.3 g, 59.4 mmol) was added.
Then, CH3I (3.4 g, 23.7 mmol) was added slowly. The mixture was
stirred at 40 °C overnight. The reaction mixture was neutralized with 1
M HCl. Diethyl ether (200 mL) was added, and the mixture was
extracted with water (2 × 50 mL) and brine (50 mL). The organic
layer was dried over Na2SO4 and concentrated. The residue was
purified by silica gel chromatography (0−30% CH2Cl2 in hexane) to
Diethyl 4-(5,5-dimethyl-1,3-dioxan-2-yl)-2-((2-ethylhexyl)-
oxy)-5-methoxy-benzyl-phosphonate (29). In a 20 mL vial was
added 28 (893 mg, 2.01 mmol) and triethyl phosphite (469 mg, 2.82
mmol). The mixture was heated in 140 °C for 2 h and then cooled to
room temperature. The residue was directly purified by silica gel
chromatography (0 → 33% EtOAc in hexane, Rf = 0.4) to give 817 mg
1
(81.2%) as a yellowish oil: H NMR (400 MHz, CDCl3) δ 7.14 (s,
1H), 6.97 (d, J = 2.6 Hz, 1H), 5.73 (s, 1H), 4.00 (m, 4H), 3.89−3.85
(m, 2H), 3.80 (s, 3H), 3.76 (d, J = 11.0 Hz, 2H), 3.68 (d, J = 10.9 Hz,
2H), 3.24 (d, J = 21.8 Hz, 2H), 1.74−1.65 (m, 1H), 1.55−1.39 (m,
4H), 1.36−1.28 (m, 7H), 1.23 (t, J = 7.1 Hz, 6H), 0.95−0.87 (m, 6H),
0.79 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 151.0, 150.9, 150.0,
145.0, 148.8, 125.8, 125.8, 121.6, 121.5, 114.4, 114.4, 110.0, 110.0,
96.9, 96.8, 77.9, 70.8, 61.9, 61.8, 56.3, 39.7, 30.7, 30.3, 29.2, 26.8, 25.5,
24.0, 23.2, 23.0, 21.9, 16.4, 16.3, 14.1, 11.2; LRMS (ES+ + H) 501.3;
HRMS (TOF MS ES+) m/z for C26H46O7P calcd 501.2981, found
501.2985.
2-[5-((2-Ethylhexyl)oxy)-4-iodo-2-methoxy-phenyl]-5,5-di-
methyl-1,3-dioxane (30). In a glovebox were added 25 (1.00 g, 2.33
mmol) in THF (50 mL) in a 100 mL two neck round bottle flask. The
solution was taken out of glovebox and cooled down to −78 °C under
Ar. A solution of n-BuLi (3.03 mmol, 1.9 mL) in hexane was added
dropwise and stirred at −78 °C for 1 h. Then I2 (0.768 g, 3.03 mmol)
of THF solution was added to the mixture and stirred for another 2 h
and temperature was allowed to increase to room temperature. H2O
(20 mL) was added to quench the reaction. CH2Cl2 (100 mL) was
added, and the mixture was extracted with water (2 × 50 mL) and
brine (50 mL). The organic layer was dried over MgSO4 and
concentrated. The residue was purified by silica gel chromatography
(0−30% CH2Cl2 in hexane) to give 722 mg (65%) of light colorless
oil: 1H NMR (400 MHz, CDCl3) δ 7.27 (s, 1H), 7.09 (s, 1H), 5.69 (s,
1H), 3.90 (d, J = 5.4 Hz, 2H), 3.78 (s, 3H), 3.75 (d, J = 11.1 Hz, 2H),
3.66 (d, J = 10.8 Hz, 2H), 1.77−1.68 (m, 1H), 1.61−1.46 (m, 4H),
1.38−1.29 (m, 7H), 0.98−0.87 (m, 9H), 0.79 (s, 3H); 13C NMR (101
MHz, CDCl3) δ 152.5, 150.9, 127.8, 122.4, 110.3, 96.7, 87.1, 77.8,
71.8, 56.6, 39.5, 30.6, 30.3, 29.1, 24.1, 23.2, 23.1, 21.9, 14.2, 11.3;
LRMS (ES+ + H) 477.1; HRMS (TOF MS ES+) m/z for C21H34O4I
calcd 477.1502, found 477.1508.
1
give 3.91 g (76.7%) light yellow oil: H NMR (400 MHz, CDCl3) δ
7.20 (s, 1H), 7.07 (s, 1H), 5.69 (s, 1H), 3.91 (d, J = 5.5 Hz, 2H), 3.79
(s, 3H), 3.75 (d, J = 11.1 Hz, 2H), 3.67 (d, J = 10.9 Hz, 2H), 1.78−
1.70 (m, 1H), 1.58−1.40 (m, 4H), 1.36−1.28 (m, 7H), 0.96−0.87 (m,
6H), 0.79 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 150.6, 150.1,
126.6, 116.4, 113.0, 111.9, 96.5, 77.8, 72.0, 56.5, 39.5, 30.5, 30.3, 29.1,
23.9, 23.2, 23.1, 21.9, 14.1, 11.2; LRMS (ES+ + H) 431.2; HRMS
(TOF MS ES+) m/z for C21H34O4Br calcd 429.1640, found 429.1637.
4-(5,5-Dimethyl-1,3-dioxan-2-yl)-2-((2-ethylhexyl)oxy)-5-
methoxy-benzaldehyde (26). In a glovebox were added 25 (1.05 g,
2.45 mmol) in THF (50 mL) in a 100 mL two neck round bottle flask.
The solution was taken out of glovebox and cooled down to −78 °C
under Ar. A solution of n-BuLi (3.18 mmol, 2.0 mL) in hexane was
added dropwise and stirred at −78 °C for 1 h. Then DMF (2 mL) was
added to the mixture and stirred for another 2 h and temperature was
allowed to increase to room temperature. H2O (20 mL) was added to
quench the reaction. CH2Cl2 (100 mL) was added, and the mixture
was extracted with water (2 × 50 mL) and brine (50 mL). The organic
layer was dried over MgSO4 and concentrated. The residue was
purified by silica gel chromatography (0−60% CH2Cl2 in hexane) to
1
give 0.82 g (88.4%) light yellow oil: H NMR (400 MHz, CDCl3) δ
10.47 (s, 1H), 7.31 (s, 1H), 5.75 (s, 1H), 4.00 (dd, J = 5.3, 1.2 Hz,
2H), 3.84 (s, 3H), 3.77 (d, J = 11.1 Hz, 2H), 3.69 (d, J = 10.8 Hz, 2H),
1.79−1.71 (m, 1H), 1.52−1.40 (m, 4H), 1.36−1.27 (m, 7H), 0.98−
0.86 (m, 6H), 0.81 (s, 3H); 13C NMR (101 MHz, CDCl3) δ 189.5,
156.6, 150.4, 134.3, 125.2, 112.0, 109.0, 96.3, 77.9, 71.1, 56.2, 39.5,
30.7, 30.3, 29.1, 24.1, 23.2, 23.0, 21.8, 14.0, 11.2; LRMS (ES+ + H)
379.2; HRMS (TOF MS ES+) m/z for C22H35O5 calcd 379.2484,
found 379.2480.
5-((2-Ethylhexyl)oxy)-4-iodo-2-methoxy-benzaldehyde (31).
30 (2.73 g, 5.73 mmol) was dissolved in a solution of trifluoroacetic
acid (4 mL), THF (20 mL) and H2O (4 mL) in 100 mL round-
bottom flask and stirred at 50 °C overnight. CH2Cl2 (100 mL) was
added, and the mixture was extracted with water (2 × 50 mL) and
brine (50 mL). The organic layer was dried over MgSO4 and
concentrated. The residue was purified by silica gel chromatography (0
→ 40% CH2Cl2 in hexane) to give 2.2 g (98.4%) as a bright yellow
solid: 1H NMR (400 MHz, CDCl3) δ 10.40 (s, 1H), 7.46 (s, 1H), 7.19
(s, 1H), 3.90−3.85 (m, 5H), 1.79−1.70 (m, 1H), 1.61−1.40 (m, 4H),
1.37−1.28 (m, 4H), 0.96−0.89 (m, 6H); 13C NMR (101 MHz,
[4-(5,5-Dimethyl-1,3-dioxan-2-yl)-2-((2-ethylhexyl)oxy)-5-
methoxy-phenyl]methanol (27). In a 100 mL two-necked round-
bottom flask was stirred 26 (1.36 g, 3.59 mol) in THF (30 mL) at 0
°C for 10 min. NaBH4 (204 mg, 5.39 mmol) was carefully added, and
the mixture was stirred overnight. Methanol was added to quench the
NaBH4. CH2Cl2 (100 mL) was added, and the mixture was extracted
with water (2 × 50 mL) and brine (50 mL). The organic layer was
dried over MgSO4 and concentrated to give colorless oil without
further purification: 1H NMR (400 MHz, CDCl3) δ 7.16 (s, 1H), 6.86
(s, 1H), 5.75 (s, 1H), 4.66 (s, 2H), 3.93 (dd, J = 5.3, 1.6 Hz, 2H), 3.80
(s, 3H), 3.76 (d, J = 10.7 Hz, 2H), 3.68 (d, J = 10.7 Hz, 2H), 2.34 (s,
7099
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Article
CDCl3) δ 189.1, 156.0, 152.4, 125.0, 123.5, 108.7, 96.6, 72.1, 56.4,
39.3, 30.5, 29.0, 24.0, 23.0, 14.1, 11.2; LRMS (ES+ + H) 391.1; HRMS
(TOF MS ES+) m/z for C16H24O3I calcd 391.0770, found 391.0768.
Proton and Carbon NMR match previous report.41
14.1, 11.3, 11.2; LRMS (ES+ + H) 651.3; HRMS (TOF MS ES+) m/z
for C33H48O5I calcd 651.2547, found 651.2550.
Regioregular Trimer Aldehyde (36). In a 100 mL two-necked
round-bottom flask was stirred 15 (297 mg, 0.60 mmol) and 35 (651
mg, 0.54 mmol) in THF (50 mL) at 0 °C for 10 min t-BuOK (91 mg,
0.8 mmol) was gradually added and stirred overnight. CH2Cl2 (100
mL) was added, and the mixture was extracted with water (2 × 50
mL) and brine (50 mL). The organic layer was dried over MgSO4 and
concentrated. The residue was then dissolved in a solution of 12 M
HCl (5 mL), THF (15 mL) and H2O (2 mL) in 100 mL round-
bottom flask and stirred at 50 °C overnight. CH2Cl2 (100 mL) was
added, and the mixture was extracted with water (2 × 50 mL) and
brine (50 mL). The organic layer was dried over MgSO4 and
concentrated. The residue was purified by silica gel chromatography (0
→ 30% CH2Cl2 in hexane, Rf = 0.3) to get crude product. The residue
and a catalytic amount of iodine (0.7 mg, 0.003 mmol) was dissolved
in toluene (100 mL) and refluxed overnight. The mixture was directly
concentrated and purified by silica gel chromatography (0 → 30%
CH2Cl2 in hexane, Rf = 0.3) to give 260 mg (53%) as a orange solid:
1H NMR (400 MHz, CDCl3) δ 10.46 (s, 1H), 7.68−7.41 (m, 4H),
7.35 (s, 1H), 7.30 (s, 1H), 7.23 (s, 1H), 7.17 (s, 1H), 7.16 (s, 1H),
7.10 (s, 1H), 4.02−3.83 (m, 15H), 1.85−1.74 (m, 3H), 1.67−1.43 (m,
12H), 1.41−1.28 (m, 12H), 1.03−0.86 (m, 18H); 13C NMR (101
MHz, CDCl3) δ 189.0, 156.58, 152.6, 151.6, 151.6, 151.4, 151.0, 135.0,
127.9, 127.7, 127.1, 126.3, 123.9, 123.6, 123.54, 123.47, 122.2, 109.94,
109.89, 109.3, 108.8, 108.5, 84.8, 71.6, 71.2, 57.2, 56.3, 56.0, 39.8, 39.7,
39.6, 30.9, 30.8, 30.7, 29.2, 29.14, 29.12, 24.3, 24.2, 24.0, 23.09, 23.07,
23.02, 14.09, 14.08, 14.06, 11.38, 11.36, 11.2; LRMS (ES+ + H) 911.4;
HRMS (TOF MS ES+) m/z for C50H72O7I calcd 911.4323, found
911.4324.
Regioregular Tetramer Aldehyde (37). In a 100 mL two-necked
round-bottom flask was stirred 15 (133 mg, 0.27 mmol) and 36 (220
mg, 0.24 mmol) in THF (50 mL) at 0 °C for 10 min t-BuOK (40 mg,
0.36 mmol) was gradually added and stirred overnight. CH2Cl2 (100
mL) was added, and the mixture was extracted with water (2 × 50
mL) and brine (50 mL). The organic layer was dried over MgSO4 and
concentrated. The residue was then dissolved in a solution of 12 M
HCl (5 mL), THF (15 mL) and H2O (2 mL) in 100 mL round-
bottom flask and stirred at 50 °C overnight. CH2Cl2 (100 mL) was
added, and the mixture was extracted with water (2 × 50 mL) and
brine (50 mL). The organic layer was dried over MgSO4 and
concentrated. The residue was purified by silica gel chromatography (0
→ 30% CH2Cl2 in hexane, Rf = 0.3) to get crude product. The residue
and a catalytic amount of iodine (0.3 mg, 0.001 mmol) was dissolved
in toluene (100 mL) and refluxed overnight. The mixture was directly
concentrated and purified by silica gel chromatography (0 → 30%
CH2Cl2 in hexane, Rf = 0.3) to give 165 mg (58.3%) as a red solid: 1H
NMR (400 MHz, CDCl3) δ 10.47 (s, 1H), 7.69−7.41 (m, 6H), 7.35
(s, 1H), 7.30 (s, 1H), 7.25 (s, 1H), 7.21−7.17 (m, 3H), 7.16 (s, 1H),
7.11 (s, 1H), 4.04−3.82 (m, 20H), 1.87−1.74 (m, 4H), 1.69−1.43 (m,
16H), 1.43−1.27 (m, 16H), 1.05−0.84 (m, 24H); 13C NMR (101
MHz, CDCl3) δ 189.0, 156.6, 152.6, 151.7, 151.6, 151.4, 151.3, 151.0,
135.1, 128.2, 128.01 127.2, 127.1, 126.9, 126.1, 124.0, 123.9, 123.7,
123.5, 123.1, 122.8, 122.0, 110.0, 109.9, 109.7, 109.3, 109.0, 108.8,
108.5, 84.6, 71.7, 71.3, 71.2, 57.2, 56.4, 56.4, 56.0, 39.8, 39.7, 39.6,
30.9, 30.8, 30.7, 29.3, 29.14, 29.12, 24.3, 24.2, 24.0, 23.19, 23.06, 23.02,
14.09, 14.06, 11.38, 11.35, 11.2; LRMS (ES+ + H) 1171.6; HRMS
(TOF MS ES+) m/z for C67H96O9I calcd 1171.6099, found
1171.6105.
[5-((2-Ethylhexyl)oxy)-4-iodo-2-methoxy-phenyl]methanol
(32). In a 100 mL two-necked round-bottom flask was stirred 31 (2.20
g, 5.64 mol) in THF (30 mL) at 0 °C for 10 min. NaBH4 (320 mg,
8.46 mmol) was carefully added, and the mixture was stirred overnight.
Methanol was added to quench the NaBH4. CH2Cl2 (100 mL) was
added, and the mixture was extracted with water (2 × 50 mL) and
brine (50 mL). The organic layer was dried over MgSO4 and
concentrated to give colorless oil without further purification (crude
1
mass 1.96 g, 88.7%): H NMR (400 MHz, CDCl3) δ 7.24 (s, 1H),
6.81 (s, 1H), 4.63 (d, J = 6.2 Hz, 2H), 3.85 (d, J = 5.5 Hz, 2H), 3.81
(s, 3H), 2.19 (t, J = 6.4 Hz, 1H), 1.79−1.69 (m, 1H), 1.61−1.41 (m,
4H), 1.37−1.30 (m, 4H), 0.96−0.88 (m, 6H); 13C NMR (101 MHz,
CDCl3) δ 152.3, 151.5, 130.2, 121.3, 112.4, 84.7, 72.2, 61.5, 56.0, 39.5,
30.5, 29.1, 23.9, 23.1, 14.1, 11.2.
1-Bromomethyl-5-((2-ethylhexyl)oxy)-4-iodo-2-methoxy-
benzene (33). In a 100 mL two-necked round-bottom flask was
stirred 32 (1.90 g, 4.84 mmol) in THF (50 mL) at 0 °C for 10 min.
Carbon tetrabromide (2.09 g, 6.30 mmol) and triphenylphosphine
(1.65 g, 6.30 mmol) was added, and the mixture was stirred overnight.
CH2Cl2 (100 mL) was added, and the mixture was extracted with
water (2 × 50 mL) and brine (50 mL). The organic layer was dried
over MgSO4 and concentrated. The residue was purified by silica gel
chromatography (0 → 20% CH2Cl2 in hexane, Rf = 0.4) to give 1.30 g
1
(59.1%) as a yellowish oil: H NMR (400 MHz, CDCl3) δ 7.26 (s,
1H), 6.78 (s, 1H), 4.50 (s, 4H), 3.85−3.82 (m, 5H), 1.78−1.70 (m,
1H), 1.61−1.42 (m, 4H), 1.37−1.30 (m, 4H), 0.98−0.88 (m, 6H); 13C
NMR (101 MHz, CDCl3) δ 152.1, 151.7, 126.8, 122.4, 113.9, 87.2,
72.1, 56.4, 39.5, 30.5, 29.1, 28.6, 23.9, 23.1, 14.2, 11.3.
Diethyl 5-((2-ethylhexyl)oxy)-4-iodo-2-methoxy-benzyl-
phosphonate (34). In a 20 mL vial was added 33 (360 mg, 0.79
mmol) and triethyl phosphite (184 mg, 1.11 mmol). The mixture was
heated in 140 °C for 2 h, and then cooled to room temperature. The
residue was directly purified by silica gel chromatography (0 → 33%
EtOAc in hexane) to give 382 mg (94.4%) as a yellowish oil: 1H NMR
(400 MHz, CDCl3) δ 7.23 (s, 1H), 6.83 (d, J = 2.7 Hz, 1H), 4.08−
3.99 (m, 4H), 3.83 (d, J = 5.5 Hz, 2H), 3.78 (s, 3H), 3.18 (d, J = 21.8
Hz, 2H), 1.76−1.69 (m, 1H), 1.57−1.47 (m, 4H), 1.35−1.29 (m, 4H),
1.25 (t, J = 7.1 Hz, 6H), 0.96−0.87 (m, 6H); 13C NMR (101 MHz,
CDCl3) δ 152.0, 152.00, 151.7, 151.7, 121.7, 121.7, 121.3, 121.2,
114.9, 114.8, 84.4, 84.3, 72.0, 62.0, 61.9, 56.3, 39.5, 30.5, 29.0, 27.4,
26.0, 23.9, 23.0, 16.4, 16.3, 14.1, 11.2; LRMS (ES+ + H) 513.1; HRMS
(TOF MS ES+) m/z for C20H35O5PI calcd 513.1267, found 513.1265.
Regioregular Dimer Aldehyde (35). In a 100 mL two-necked
round-bottom flask was stirred 15 (379 mg, 0.79 mmol) and 17 (340
mg, 0.87 mmol) in THF (50 mL) at 0 °C for 10 min t-BuOK (133 mg,
1.2 mmol) was gradually added and stirred overnight. CH2Cl2 (100
mL) was added, and the mixture was extracted with water (2 × 50
mL) and brine (50 mL). The organic layer was dried over MgSO4 and
concentrated. The residue was then dissolved in a solution of 12 M
HCl (5 mL), THF (15 mL) and H2O (2 mL) in 100 mL round-
bottom flask and stirred at 50 °C overnight. CH2Cl2 (100 mL) was
added, and the mixture was extracted with water (2 × 50 mL) and
brine (50 mL). The organic layer was dried over MgSO4 and
concentrated. The residue was purified by silica gel chromatography (0
→ 30% CH2Cl2 in hexane, Rf = 0.3) to get crude product. The residue
and a catalytic amount of iodine (1 mg, 0.004 mmol) was dissolved in
toluene (100 mL) and refluxed overnight. The mixture was directly
concentrated and purified by silica gel chromatography (0 → 30%
CH2Cl2 in hexane, Rf = 0.3) to give 350 mg (68.1%) as a yellow solid:
1H NMR (400 MHz, CDCl3) δ 10.46 (s, 1H), 7.54, 7.49 (ABq, J =
Regiorandom Dimer Aldehyde (38). In a 100 mL two-necked
round-bottom flask was stirred 17 (250 mg, 0.64 mmol) and 29 (353
mg, 0.71 mmol) in THF (50 mL) at 0 °C for 10 min t-BuOK (86.3
mg, 0.77 mmol) was gradually added and stirred overnight. CH2Cl2
(100 mL) was added, and the mixture was extracted with water (2 ×
50 mL) and brine (50 mL). The organic layer was dried over MgSO4
and concentrated. The residue was then dissolved in a solution of 12
M HCl (5 mL), THF (15 mL) and H2O (2 mL) in 100 mL round-
bottom flask and stirred at 50 °C overnight. CH2Cl2 (100 mL) was
added, and the mixture was extracted with water (2 × 50 mL) and
brine (50 mL). The organic layer was dried over MgSO4 and
16.8 Hz, 2H), 7.34 (s, 1H), 7.31 (s, 1H), 7.20 (s, 1H), 7.08 (s, 1H),
3.99 (d, J = 5.5 Hz, 2H), 3.93−3.83 (m, 8H), 1.83−1.73 (m, 2H),
1.63−1.41 (m, 8H), 1.40−1.27 (m, 8H), 0.99−0.86 (m, 12H); 13C
NMR (101 MHz, CDCl3) δ 189.0, 156.5, 152.6, 151.8, 151.1, 134.5,
127.1, 126.8, 124.1, 123.5, 123.1, 110.2, 108., 108.7, 86.0, 71.6, 71.2,
57.2, 56.0, 39.7, 39.6, 30.8, 30.7, 29.1, 29.1, 24.2, 24.0, 23.1, 23.0, 14.1,
7100
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The Journal of Organic Chemistry
Article
concentrated. The residue was purified by silica gel chromatography (0
→ 30% CH2Cl2 in hexane, Rf = 0.3) to get crude product. The residue
and a catalytic amount of iodine (0.8 mg, 0.003 mmol) was dissolved
in toluene (100 mL) and refluxed overnight. The mixture was directly
concentrated and purified by silica gel chromatography (0 → 30%
CH2Cl2 in hexane, Rf = 0.3) to give 149 mg (35.7%) as a yellow solid:
1H NMR (400 MHz, CDCl3) δ 10.42 (s, 1H), 7.55, 7.52 (ABq, J =
16.8 Hz, 2H), 7.33 (s, 1H), 7.32 (s, 1H), 7.21 (s, 1H), 7.08 (s, 1H),
3.96−3.83 (m, 10H), 1.84−1.73 (m, 2H), 1.56−1.40 (m, 8H), 1.37−
1.26 (m 8H), 0.99−0.85 (m, 12H); 13C NMR (101 MHz, CDCl3) δ
189.1, 156.4, 152.6, 151.6, 150.8, 134.5, 127.3, 125.9, 124.0, 123.7,
122.7, 110.2, 108.7, 107.9, 85.8, 71.9, 71.5, 56.8, 55.9, 39.6, 39.6, 30.80,
30.77, 29.11, 29.08, 24.23, 24.20, 23.1, 14.1, 11.3; LRMS (ES+ + H)
651.2; HRMS (TOF MS ES+) m/z for C33H48O5I calcd 651.2547,
found 651.2540.
give 107 mg (57.6%) as a red sticky oil: 1H NMR (400 MHz, CDCl3)
δ 7.59−7.41 (m, 8H), 7.30 (s, 2H), 7.21−7.16 (m, 6H), 7.12 (s, 2H),
4.04−3.82 (m, 25H), 1.87−1.75 (m, 5H), 1.69−1.44 (m, 20H), 1.42−
1.28 (m, 20H), 1.03−0.95 (s, 15H), 0.94−0.87 (m, 15H); 13C NMR
(101 MHz, CDCl3) δ 152.6, 151.41, 151.40, 151.37, 151.35, 151.21,
151.17, 128.3, 127.5, 127.4, 127.2, 127.1, 126.9, 126.7, 123.7, 123.41,
123.38, 123.1, 122.7, 122.1, 122.0, 110.4, 110.1, 110.0, 109.0, 108.3,
107.70, 107.68, 84.4, 72.0, 71.8, 71.6, 71.4, 56.8, 56.5, 56.1, 56.0, 39.9,
39.78, 39.76, 39.6, 30.9, 30.8, 29.3, 29.24, 29.20, 29.16, 24.34, 24.30,
24.29, 24.22, 23.2, 23.1, 14.18, 14.15, 14.14, 11.49, 11.46, 11.40, 11.37;
LRMS (ES+ + H) 1529.7; HRMS (TOF MS ES+) m/z for
C83H119O10I2 calcd 1529.6893, found 1529.6868.
ASSOCIATED CONTENT
■
S
* Supporting Information
Regioregular Pentamer PPV (2). In a 100 mL two-necked
round-bottom flask was stirred 34 (73 mg, 0.14 mmol) and 37 (152
mg, 0.13 mmol) in THF (50 mL) at 0 °C for 10 min t-BuOK (22 mg,
0.2 mmol) was gradually added and stirred overnight. CH2Cl2 (100
mL) was added, and the mixture was extracted with water (2 × 50
mL) and brine (50 mL). The organic layer was dried over MgSO4 and
concentrated. The residue and a catalytic amount of iodine (0.2 mg,
0.0007 mmol) was dissolved in toluene (100 mL) and refluxed
overnight. The mixture was directly concentrated and purified by silica
gel chromatography (0 → 30% CH2Cl2 in hexane, Rf = 0.3) to give
103 mg (51.9%) as a red solid: 1H NMR (400 MHz, CDCl3) δ 7.60−
7.40 (m, 8H), 7.30 (d, J = 2.1 Hz, 2H), 7.22−7.19 (m, 4H), 7.18 (s,
1H), 7.17 (s, 1H), 7.12 (s, 1H), 7.08 (s, 1H), 4.03−3.81 (m, 25H),
1.88−1.73 (m, 5H), 1.71−1.45 (m, 20H), 1.44−1.29 (m, 20H), 1.06−
0.87 (m, 30H); 13C NMR (101 MHz, CDCl3) δ 152.7, 152.5, 151.69,
151.57, 151.5, 151.43, 151.39, 151.36, 151.31, 128.13, 128.08, 127.5,
127.4, 127.2, 127.1, 126.7, 126.6, 124.3, 123.7, 123.6, 123.5, 123.4,
123.0, 123.0, 122.8, 122.5, 122.4, 110.0, 109.82, 109.79, 109.2, 109.1,
109.0, 108.9, 108.5, 85.1, 84.6, 72.0, 71.7, 71.30, 71.29, 71.2, 57.2,
56.42, 56.36, 39.91, 39.90, 39.7, 39.6, 39.5, 30.9, 30.8, 30.6, 29.24,
29.18, 29.14, 24.34, 24.27, 24.0, 23.14, 23.11, 14.17, 14.15, 14.14,
11.44, 11.42, 11.41, 11.28; LRMS (ES+ + H) 1529.7; HRMS (TOF
MS ES+) m/z for C83H119O10I2 calcd 1529.6893, found 1529.6897.
Regiorandom Pentamer PPV (3). In a 100 mL two-necked
round-bottom flask was stirred 18 (77.4 mg, 0.14 mmol) and 35
(187.6 mg, 0.28 mmol) in THF (50 mL) at 0 °C for 10 min t-BuOK
(39.3 mg, 0.35 mmol) was gradually added and stirred overnight.
CH2Cl2 (100 mL) was added, and the mixture was extracted with
water (2 × 50 mL) and brine (50 mL). The organic layer was dried
over MgSO4 and concentrated. The residue and a catalytic amount of
iodine (0.2 mg, 0.0007 mmol) was dissolved in toluene (100 mL) and
refluxed overnight. The mixture was directly concentrated and purified
by silica gel chromatography (0 → 30% CH2Cl2 in hexane, Rf = 0.3) to
1
Figures containing the expanded aromatic regions of H and
13C NMR spectra for compounds 1−4; H NMR and 13C
1
NMR spectra of all compounds. This material is available free
of charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*E-mail: kplunkett@chem.siu.edu.
■
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
The authors would like to thank Professor David A. Vanden
Bout for helpful discussions. K.N.P. thanks Southern Illinois
University for startup funds.
REFERENCES
■
(1) Kim, Y.; Cook, S.; Tuladhar, S. M.; Choulis, S. A.; Nelson, J.;
Durrant, J. R.; Bradley, D. D. C.; Giles, M.; McCulloch, I.; Ha, C.-S.;
Ree, M. Nat. Mater. 2006, 5, 197−203.
(2) Woo, C. H.; Thompson, B. C.; Kim, B. J.; Toney, M. F.; Frec
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(3) Jiang, Y.; Hong, S.; Oh, J. H.; Mondal, R.; Okamoto, T.;
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(4) McCulloch, I.; Heeney, M.; Bailey, C.; Genevicius, K.;
MacDonald, I.; Shkunov, M.; Sparrowe, D.; Tierney, S.; Wagner, R.;
Zhang, W.; Chabinyc, M. L.; Kline, R. J.; McGehee, M. D.; Toney, M.
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1
́
(5) Osaka, I.; Zhang, R.; Sauve, G.; Smilgies, D.-M.; Kowalewski, T.;
give 114 mg (51.7%) as a red solid: H NMR (400 MHz, CDCl3) δ
McCullough, R. D. J. Am. Chem. Soc. 2009, 131, 2521−2529.
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7.57−7.41 (m, 8H), 7.29 (s, 2H), 7.21 (s, 2H), 7.19 (d, J = 1.2 Hz,
2H), 7.16 (d, J = 1.0 Hz, 2H), 7.11 (s, 2H), 4.01−3.82 (m, 25H),
1.87−1.73 (m, 5H), 1.68−1.44 (m, 20H), 1.42−1.29 (m, 20H), 1.03−
0.95 (m, 15H), 0.94−0.87 (m, 15H); 13C NMR (101 MHz, CDCl3) δ
152.6, 151.56, 151.56, 151.43, 151.40, 151.28, 151.15, 151.10, 128.1,
127.5, 127.3, 127.2, 127.1, 126.7, 123.7, 123.4, 123.0, 123.0, 122.9,
122.6, 110.2, 110.0, 109.9, 108.9, 108.4, 108.4, 108.1, 108.1, 84.67,
84.56, 71.63, 71.59, 71.56, 71.2, 57.2, 56.4, 56.0, 55.9, 39.9, 39.8, 39.7,
30.91, 30.88, 30.8, 29.22, 29.17, 24.30, 24.25, 23.16, 23.15, 23.12,
14.16, 14.15, 11.4; LRMS (ES+ + H) 1529.7; HRMS (TOF MS ES+)
m/z for C83H119O10I2 calcd 1529.6893, found 1529.6886.
Regiorandom Pentamer PPV (4). In a 100 mL two-necked
round-bottom flask was stirred 18 (65.3 mg, 0.12 mmol) and 38
(158.4 mg, 0.24 mmol) in THF (50 mL) at 0 °C for 10 min t-BuOK
(34.1 mg, 0.30 mmol) was gradually added and stirred overnight.
CH2Cl2 (100 mL) was added, and the mixture was extracted with
water (2 × 50 mL) and brine (50 mL). The organic layer was dried
over MgSO4 and concentrated. The residue and a catalytic amount of
iodine (0.2 mg, 0.0006 mmol) was dissolved in toluene (100 mL) and
refluxed overnight. The mixture was directly concentrated and purified
by silica gel chromatography (0 → 30% CH2Cl2 in hexane, Rf = 0.3) to
(7) Zhang, F.; Hu, Y.; Schuettfort, T.; Di, C.; Gao, X.; McNeill, C. R.;
Thomsen, L.; Mannsfeld, S. C. B.; Yuan, W.; Sirringhaus, H.; Zhu, D. J.
Am. Chem. Soc. 2013, 135, 2338−2349.
(8) Kline, R. J.; DeLongchamp, D. M.; Fischer, D. A.; Lin, E. K.;
Richter, L. J.; Chabinyc, M. L.; Toney, M. F.; Heeney, M.; McCulloch,
I. Macromolecules 2007, 40, 7960−7965.
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