Synthesis of biaryls and oligoarenes using aryl[2-(hydroxymethyl)phenyl] dimethylsilanes

Article abstract of DOI:10.1246/bcsj.20090325

Through intramolecular activation, highly stable aryl[2-(hydroxymethyl) phenyl]dimethylsilanes can selectively transfer their aryl groups to effect a cross-coupling reaction with various aryl bromides and chlorides in the presence of a weak non-fluoride base and a palladium/copper catalyst. This reaction tolerates a wide range of functional groups, producing the corresponding functionalized biaryls in high yields with excellent chemoselectivity. Newly disclosed reaction conditions allow the recovery of a cyclic silyl ether in modest-to-good yields and reuse for the synthesis of the arylsilanes. The introduction of two isopropyl groups on the silicon center instead of methyl groups improves the stability and allows quantitative recovery of the silicon residue. Finally, aryl halides having an O-protected [2- (hydroxymethyl)phenyl] dimethylsilyl group cross-couple with the arylsilane reagents to give silyl-functionalized biaryls. Upon deprotection, the biaryls further react with the silylated electrophiles. The iterative cross-couplingdeprotection sequences allow rapid assembly of silylated oligoarenes. Syntheses of di- and trisilyloligoarenes are also achieved by use of orthogonal O-protecting groups.

Full text of DOI:10.1246/bcsj.20090325

554
Bull. Chem. Soc. Jpn. Vol. 83, No. 5, 554–569 (2010)
© 2010 The Chemical Society of Japan
Synthesis of Biaryls and Oligoarenes Using
Aryl[2-(hydroxymethyl)phenyl]dimethylsilanes
³
³³
Jinshui Chen, Masaaki Tanaka, Akhila K. Sahoo, Masahide Takeda,
Akira Yada, Yoshiaki Nakao,* and Tamejiro Hiyama*
Department of Material Chemistry, Graduate School of Engineering, Kyoto University,
Katsura, Nishikyo-ku, Kyoto 615-8510
Received December 9, 2009
E-mail: yoshiakinakao@npc05.mbox.media.kyoto-u.ac.jp, thiyama@z06.mbox.media.kyoto-u.ac.jp
Through intramolecular activation, highly stable aryl[2-(hydroxymethyl)phenyl]dimethylsilanes can selectively
transfer their aryl groups to effect a cross-coupling reaction with various aryl bromides and chlorides in the presence of a
weak non-fluoride base and a palladium/copper catalyst. This reaction tolerates a wide range of functional groups,
producing the corresponding functionalized biaryls in high yields with excellent chemoselectivity. Newly disclosed
reaction conditions allow the recovery of a cyclic silyl ether in modest-to-good yields and reuse for the synthesis of
the arylsilanes. The introduction of two isopropyl groups on the silicon center instead of methyl groups improves the
stability and allows quantitative recovery of the silicon residue. Finally, aryl halides having an O-protected [2-
(hydroxymethyl)phenyl]dimethylsilyl group cross-couple with the arylsilane reagents to give silyl-functionalized biaryls.
Upon deprotection, the biaryls further react with the silylated electrophiles. The iterative cross-coupling-deprotection
sequences allow rapid assembly of silylated oligoarenes. Syntheses of di- and trisilyloligoarenes are also achieved by use
of orthogonal O-protecting groups.
Biaryls are ubiquitous in natural products, pharmaceuticals,
of the fluoride and alkoxide activators.6 However, these con-
ventional arylsilane reagents suffer from the kinetic instability
of heteroatom-Si bonds toward moisture, bases, and/or acids
and poor chemoselectivity of the reaction conditions caused
by the strong nucleophilic activators. Arylsilanolates have
emerged as a convenient and mild arylating agent for silicon-
based biaryl synthesis with high chemoselectivity.7 While the
use of arylsilanols first allowed the use of Cs2CO3 as a mild
base activator,8 silanolates have further eliminated the need
for the external base, thus suppressing both the undesirable
dehydration of silanols to form siloxanes and protodesilylation
caused possibly by the conjugate acid derived from the base. It
has also been suggested that the transmetalation of silanolates
to palladium(II) proceeds through palladium silanolates as a
key intermediate, which undergoes intramolecular transmeta-
lation in a manner similar to and/or different from the
pentacoordinate silicates.9
The use of aryl(triorgano)silanes is another promising
strategy to establish a practically useful silicon-based protocol
for biaryl synthesis. We initially developed aryl(triallyl)silanes
as a stable tetraorganosilane reagent for the cross-coupling
reaction.10 The reagents serve as “masked aryl(fluoro)silanes or
arylsilanols” to form aryl(fluoro)silanes or arylsilanols in situ
through deallylation upon a treatment with fluoride and react
with a range of aryl bromides or chlorides in the presence of a
palladium catalyst. To further establish fluoride-free silicon-
based cross-coupling reactions using tetraorganosilanes, we
have developed alkenyl- and aryl[2-(hydroxymethyl)phenyl]-
dimethylsilanes 1 designed on the basis of the related allyl- and
benzylsilane reagents for carbonyl addition11 and the seminal
and materials. Metal-catalyzed cross-coupling reactions1 of
arylmetals with aryl halides or pseudo halides have been
established as a standard protocol to access the biaryl structure
in a regiochemically well-defined manner.2 Significant efforts
have been made to improve the efficiency of the catalysis
by thoroughly investigating late-transition metal catalysts and
ligands over the last forty years. Consequently, a number of
reliable methods based on the development of catalyst systems
with high turnover numbers are now available. Some such
protocols have been commercialized successfully even on an
industrial scale.3
Various arylmetals have also been examined to establish a
highly chemoselective protocol for biaryl synthesis. Of various
types of arylmetal reagents, arylsilanes have many advantages
over other aryl nucleophiles such as ready availability based on
the rich abundance of silicon, inherent stability derived from
less polarized C-Si bonds, and non-toxicity of organosilicon
compounds. Initial studies on the cross-coupling reaction using
arylsilane reagents involved aryl(halo)silanes that are activated
by strong nucleophiles such as fluoride4 and hydroxide5 to form
pentacoordinate arylsilicates to undergo transmetalation with
palladium(II) species generated upon the oxidative addition
of aryl electrophiles to palladium(0). More recently, aryl(tri-
alkoxy)silanes have been frequently employed in the presence
³
Present address: Department of Chemistry, University of
Miami, Coral Gables, Florida, USA
³³ Present address: School of Chemistry, University of
Hyderabad, Hyderabad, India
Published on the web April 29, 2010; doi:10.1246/bcsj.20090325

J. Chen et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
555
observations that proximal hydroxy groups promote the trans-
metalation of tetraorganosilicon compounds to copper(I)12 and
palladium(II) (eq 1).13 The tetraorganosilicon reagents partic-
ipate in the palladium-catalyzed cross-coupling reaction in the
presence of K2CO3 as a mild and inexpensive base promoter to
allow high chemoselectivity.14 Transmetalation of 1 is sup-
posed to proceed through pentacoordinate silicates15 that
deliver an axial or equatorial organic group on silicon to the
transition metal center intramolecularly. Resulting cyclic silyl
ether 2 can be readily recovered by distillation and reused for
the synthesis of the silicon reagent. The ready reusability of the
metal residue in such transition metal-catalyzed reactions of
main group organometallic reagents has never been addressed
and should be an important and advantageous feature of this
protocol, especially when it is applied to an industrial-scale
synthesis.
addition, we demonstrate that the reactivity of the C-Si bond of
the arylsilane reagents can be switched off simply by protecting
the hydroxy group and that aryl halides having the “off-
positioned” silyl group serve as an electrophile for the biaryl
synthesis. Deprotection then turns the switch “on” to allow the
second cross-coupling reaction, and iterative operations of
cross-coupling and deprotection allow silicon-based rapid
assembly of oligoarenes with a silyl terminus.16 Such reagent
designs with a reversible switch of reactivity have only been
available recently with organoborane reagents17 and have never
been demonstrated with other metal reagents.
PdCl2 (3.0 mol %)
L (4.0 mol %)
CuI (10 mol %)
K2CO3 (2.0 equiv)
HO
Ar2
Ar1 Ar2
(+ 2)
+
ð2Þ
I
Ar1 Si
Me2
H2O (2.0 equiv)
DMSO, 50 °C
<5%
cat. Pd
(cat. Cu)
1
HO
NCy
O
X R2
R1 R2
ð1Þ
+
+
R1 Si
Me2
Si
K2CO3
PPh2
L
Me2
R1 = alkenyl, aryl
1
2
R2 = alkenyl, aryl, allyl, benzyl
X = (pseudo) halogen
Results and Discussion
transmetalation possibly through
Biaryl Synthesis through Cross-Coupling Reaction of 1
with Aryl Bromides and Chlorides. The main objective of
our research plan is to optimize the reaction conditions for the
cross-coupling of arylsilanes 1 with aryl halides under fluoride-
free conditions and to recover cyclic silyl ether 2 in good yield.
Furthermore, reuse of 2 in the synthesis of starting arylsilanes
would testify the atom-economical cross-coupling process. At
the onset, the cross-coupling reaction of [2-(hydroxymethyl)-
phenyl](dimethyl)phenylsilane (1a) with unactivated 4-
bromoanisole (3a) with a catalyst system including PdCl2
(5.0 mol %), the iminophosphine ligand (L, 5.0 mol %), CuI
(10 mol %), K2CO3 (2.0 equiv), and H2O (2.0 equiv) in DMSO
at 80 °C for 22 h was examined to provide desired 4-
methoxybiphenyl (4aa) in 21% yield as estimated by GC
analysis; the presence of unreacted 3a and formation of benzyl
alcohol from 1a were also observed. These observations clearly
reveal that cyclic silyl ether 2 is not stable under the above
conditions. We speculated that the nature and the amount of
copper salts, bases, solvents, water, and reaction temperature
determined the stability of the cyclic silyl ether 2 under the
reaction conditions. With these factors in mind, an extensive
survey of the reaction parameters in the cross-coupling of 1a
(1.5 mmol) with 3a (1.0 mmol) has led to an optimum set of
conditions including [(allyl)PdCl]2 (1 mol % Pd), RuPhos18
(2.1 mol %), CuI (3.0 mol %), and K2CO3 (2.5 mmol) in THF-
DMF (3:1) at 75 °C, giving 4-methoxybiphenyl (4aa) in 91%
yield after 23 h (Entry 1 of Table 1). It is worth noting that
cyclic silyl ether 2 mostly tolerates these reaction conditions;
the yield was estimated to be 72% on the basis of GC analysis.
Among palladium catalysts including PdCl2, PdBr2, Pd(OAc)2,
[(allyl)PdCl]2, and Pd2(dba)3 screened under the above con-
ditions, [(allyl)PdCl]2 turned out to be superior. Exploration of
various electron-donating and bulky phosphine ligands such as
RuPhos, related dialkyl(biaryl)phosphines, and PCy3 revealed
that RuPhos in combination with [(allyl)PdCl]2 and K2CO3 was
found to be effective. With the optimized palladium catalyst set
M
O
O
Me
Me
or
Si
R1
M
R1 Si
Me
Me
M = Pd(II) or Cu(I)
Aryl[2-(hydroxymethyl)phenyl]dimethylsilanes cross-cou-
ple with aryl iodides in the presence of palladium and copper
catalysts (eq 2).14a,14b However, the initial conditions led to
poor recovery of 2, and benzyl alcohol was detected as a
plausible fate of 2. It seems that cyclic silyl ether 2 is further
coordinated by a hydroxide, iodide, or chloride ion under the
reaction conditions to form pentacoordinate silicate A. For-
mation of 2-(siloxymethyl)phenylcopper species B is evident
through transmetalation of A with copper, and protonolysis of
B finally produces benzyl alcohol (Scheme 1). We disclose
herein modified reaction conditions and reagent design for the
cross-coupling reaction of the 2-(hydroxymethyl)phenyl-sub-
stituted arylsilanes with aryl bromides and chlorides to give
both biaryls and reusable silicon residue 2 in high yields. In
Me Me
Cu OSiMe2X
X
Si O
I−Cu
X
2
A
B
OH
H2O
SiMe2X2
and/or
+
X = I, Cl, or OH
(SiMe2O)n
observed
predominantly
by GC
Scheme 1. Possible fate of 2 under the reaction conditions.

556
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
Synthesis of Biaryls and Oligoarenes
Table 1. Phenylation of Aryl Bromides with 1a
and the base in hand, effects of copper salts and solvents were
surveyed. Of various copper salts used, CuI was found to be the
best. The absence of the copper co-catalyst gave lower yield of
the biaryl, suggesting an arylcopper species seems to be a
major arylating agent under the modified reaction conditions.14
The yield of 2 was improved when a small amount of CuI and
less polar solvents such as THF and 1,4-dioxane in the absence
of water were utilized in the reaction. Although the absence of
water in the reaction suppresses the decomposition of 2 to
benzyl alcohol, the yield of 4aa dropped drastically. To avoid
the use of water, solvents consisting of a mixture of highly
polar aprotic and less polar aprotic solvents were investigated.
Various combinations of mixed solvents from DMSO, DMF,
THF, and 1,4-dioxane in different ratios showed that THF-
DMF (3:1) was highly effective.
[(allyl)PdCl]2 (1 mol % Pd)
RuPhos (2.1 mol %)
CuI (3 mol %)
Ph
HO
Br
K2CO3 (2.5 mmol)
+
+ 2
R
R
Ph Si
THF−DMF (3:1), 75 °C
Oi-Pr
Me2
1a
4
3
(1.2−1.5 mmol)
(1.0 mmol)
i-PrO PCy2
RuPhos
Time Yield of Yield of
/h
Entry
3
4/%a)
2/%b)
Br
R
Bromobenzenes with a variety of substituents underwent the
cross-coupling reaction with 1a (Entries 2-18). It is worth
noting that the C-Si bond in 1a is exclusively activated over
the C-Sn bond in 3c (Entry 3), which has been believed to be
considerably more reactive than C-Si bonds, although the
para-bromo group may reduce the reactivity of the particular
C-Sn bond. The C-B bond in 3d also remained intact when the
silicon reagent was pretreated with BuLi as a base to form
lithium alkoxide, and the coupling reaction was performed in
the absence of K2CO3 (Entry 4). The original conditions using
K2CO3 as a base gave fair amounts of a polymeric insoluble
material, which might be derived from competitive reactions of
the C-B bond. Various electron-withdrawing functional groups
including carbonyls, cyano, and nitro were also tolerated
(Entries 5-12). K2CO3 as a mild base activator allows the use
of aryl bromides having not only free amino and hydroxy
groups but also a silyl protecting group, which does not survive
under the conventional fluoride activation (Entries 13-15). The
reaction can be performed on a gram-scale; the reusable silicon
residue was isolated in good yields by the simple distillation of
the crude products (ex. Entry 16). Several heteroaryl bromides
also participated in the phenylation reaction in good yields
(Entries 19-22).
In a manner similar to the reaction of phenylsilane 1a,
arylsilanes 1b-1g underwent the cross-coupling reaction with
bromobenzene (3w) in good to excellent yields (Table 2),
regardless of the electronic nature of their substituents (Entries
1-3). Highly sterically demanding mesitylsilane 1f gave the
coupling product 4fw in good yield (Entry 5). The cross-
coupling of 2-thienylsilane 1g proceeded successfully in the
presence of PdCl2(dppf)¢CH2Cl2 as a catalyst instead of the
[(allyl)PdCl]2/RuPhos system (Entry 6). The use of the Pd/
RuPhos system gave 4au in a lower yield with complete
conversion of 1g. The less electron-donating nature of DPPF
might be beneficial for transmetalation with this particular
silicon reagent that would be rather labile under the reaction
conditions compared with substituted phenylsilanes.
1
2
R = OMe (3a)
Me (3b)
23
19
10
11
25
21
10
9
21
9
21
12
91 (4aa)
86 (4ab)
88 (4ac)
81 (4ad)
85 (4ae)
85 (4af)
81 (4ag)
91 (4ah)
87 (4ai)
92 (4aj)
97 (4ak)
91 (4al)
72
71
>95
66
76
76
79
82
88
81
3
SnBu3 (3c)
4c)
5
B(pin) (3d)d)
F (3e)
6
7
8
9
10
11
12
Cl (3f)
CO2Et (3g)
CHO (3h)
Ac (3i)
CN (3j)
NO2 (3k)
CF3 (3l)
70
84
Br
R
13
14
R = NH2 (3m)
CH2OH (3n)
22
22
95 (4am)
92 (4an)
75 (4ao)
87 (4ap)
77
68
15
CH2OSiMe2t-Bu (3o) 26
Me (3p)
Br
75
16e)
14
91f)
O
O
17
18
19
21
88 (4aq)
88 (4ar)
65 (4as)
91
>95
53
3q
Br
22
22
3rr
Br
Br
N
3s
20
21
22
21
11
22
97 (4at)
88 (4au)
83 (4av)
92
90
70
N
3t
S
Br
3u
Br
S
3v
Although we have established highly general reaction
conditions to obtain biaryls in high yields, the recovery of
cyclic silyl ether 2 is not always satisfactory. Indeed, we
observed benzyl alcohol in significant amounts as detected by
a) Isolated yields based on 3. b) Estimated by GC based on 1a
using nonane as an internal standard. c) Treatment of 1a with
n-BuLi (both 1.5 mmol) at ¹78 °C to rt was followed by the
reaction with 3d in the absence of K2CO3. d) B(pin) = 4-
(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl). e) Run on a 20-
mmol scale. f) Isolated yield based on 1a (ca. 90% purity).
1
GC and H NMR when the yield of 2 was modest (ex. Entries
14 and 19 of Table 1). In order to improve the stability of 2
under the reaction conditions, we designed a silicon reagent 1¤a

J. Chen et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
557
Table 2. Arylation of Bromobenzene (3w)
Table 3. Phenylation of Aryl Chlorides with 1¤a
[(allyl)PdCl]2 (1 mol % Pd)
RuPhos (2.1 mol %)
CuI (3 mol %)
[(allyl)PdCl]2 (1 mol % Pd)
RuPhos (2.1 mol %)
CuI (3 mol %)
Ph
Cl
Si
Ph
K2CO3 (2.5 mmol)
K2CO3 (2.5 mmol)
+
+ 2'
+
+ 2
1'a
Br Ph
R
R
THF−DMF (3:1), 50 °C
THF−DMF (3:1), 75 °C
(1.5 mmol)
R
R
4
(1.0 mmol)
4
1b−1g
3w
HO
(1.2−1.5 mmol) (1.0 mmol)
Si =
Si
Time
/h
Yield of
4/%a)
Yield of
2¤/%b)
Entry
R in Cl-Ar
Me2
1
2
3
4
5
6
OMe
Me
CO2Et
CHO
Ac
23
48
15
42
29
18
41 (4aa)c)
70 (4ab)c)
96 (4ag)
94 (4ah)
95 (4ai)
>95
>95
>95
86d)
>95
>95
Time
/h
Yield of
Yield of
2/%b)
Entry
1
4/%a)
Si
R
NO2
90 (4ak)
1
2
3
R = Me (1b)
F (1c)
22
25
22
88 (4ab)
95 (4ae)
97 (4aj)
76
54
46
a) Isolated yields based on the aryl chloride. b) Estimated by
GC based on 1¤a using nonane as an internal standard.
c) Estimated by 1H NMR using 1,3,5-trimethoxybenzene as an
internal standard. d) Isolated yield based on 1¤a.
CN (1d)
Si
4
14
85 (4ew)
82
Me
1e
available aryl electrophiles (Table 3). While the reactions of
1¤a with electron-rich aryl chlorides under conditions similar
to those for aryl bromides produced the biaryls less efficiently
(Entries 1 and 2), electron-deficient substrates successfully
cross-coupled with 1¤a to afford the corresponding biaryls and
2¤ in good to excellent yields (Entries 3-6). The reactions
performed at 75 °C showed some decomposition of cyclic silyl
ether 2¤.
Me
Si
5c),d)
7
4
85 (4fw)
91 (4au)
94
92
Me
Me
1f
S
Si
6d),e)
1g
Oligoarene Synthesis through Iterative Cross-Coupling
Reaction of 1 with Silylated Aryl Bromides. We next turned
our attention to applications of the present biaryl synthesis to
the efficient synthesis of oligoarenes. As briefly mentioned in
the introduction, biaryls constitute an important structural
element in photonic and optoelectronic materials such as
organic light-emitting diodes, field-effect transistors, semi-
conductors, and fluorescent sensors. However, extension of
biaryls to oligoarenes is essential in order to understand
electronic properties of functional ³-materials and assemble
organic electronic materials which absorb and emit visible light
at longer wavelengths.19 Unlike simple biaryl synthesis, the
assembly of oligoarenes requires the installation of a leaving
group or a metallic center at terminal arenes to further extend
the oligoarene structures. These additional operations make the
entire sequence leading to the desired oligoarenes tedious
multi-step procedures. An iterative cross-coupling strategy
using metalated organic halides would streamline the synthesis
of oligoarenes with well-defined structures (Scheme 2). Never-
theless, it is difficult to control their reaction modes (cross-
coupling vs. homo-coupling, etc.) without the precise discrim-
ination between the metallic moieties.20,21
We envisaged that our arylsilane reagents could serve as a
useful building block for the iterative cross-coupling scheme.
Because the enhanced reactivity of the silicon reagents is
“turned off” simply upon the protection of the hydroxy group,
reactive and unreactive silyl groups can be readily discrimi-
nated. Moreover, use of various types of O-protecting groups
allows differentiation of several types of unreactive silyl groups
by the independent deprotection of carefully chosen orthogonal
protecting groups.
a) Isolated yields based on 3w. b) Estimated by GC based on 1
using nonane as an internal standard. c) Run with 1 mol % of
CuI. d) Run with K2CO3 ground and dried at 120 °C overnight.
e) PdCl2(dppf)¢CH2Cl2 (1 mol %) as a catalyst.
having two bulkier i-Pr groups in place of two Me groups on
silicon to suppress the decomposition of the silicon residue by
steric hindrance (eq 3). As demonstrated in eq 3, the reactions
of 1¤a with several aryl bromides proceeded equally well, and
both cyclic silyl ether 2¤ and biaryls 4 were obtained in good
to excellent yields. Treatment of 2¤ with phenylmagnesium
bromide gave 1¤a in 90% yield, demonstrating that the
modified silicon residue is also reusable for regeneration of
the arylsilane reagents (eq 4).
HO
O
Si
Ph Si
[(allyl)PdCl]2 (1 mol % Pd)
RuPhos (2.1 mol %)
CuI (3 mol %)
i-Pr2
i-Pr2
1’a
2’
(1.2−1.3 mmol)
>95% by GC
K2CO3 (2.5 mmol)
+
+
ð3Þ
ð4Þ
THF−DMF (3:1), 75 °C
Br Ar
3
(1.0 mmol)
Ph Ar
4an: 90% (21 h)
4ao: 86% (16 h)
Ph−MgBr + 2'
1'a
90%
THF, 0 °C to rt, overnight
50 mmol scale
Having had the silicon reagents cross-couple with aryl
bromides giving both biaryls and reusable silicon residue 2¤ in
good yields, we briefly examined the cross-coupling reaction
with aryl chlorides, which are less expensive and more easily

558
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
Synthesis of Biaryls and Oligoarenes
π
+
π
m
X
m*
a
Si
6hc
Ph2N
Oct Oct
93%
m = m*
m ≠ m*
R
5'e (1.0 equiv) b (17 h)
π
π
π
π
m*,
m*
π
π
m*
n
π
and/or X
m*
π
X
m**
m* ≠ m**
n
NEt
Ph2N
Oct Oct
π
π
π
m**
R
R = Si**: 12' (87%)
Si: 12 (95%)
c
m, m*, m** = Mg, Zn, Sn, B, Si
S
X = (pseudo)halogen
5'f (1.0 equiv) b (24 h)
well-defined oligoarenes
Scheme 2. Cross-coupling with metalated electrophiles.
NEt
Ph2N
Si*
Oct Oct
6gf
R = Si**: 13' (78%)
Si: 13 (85%)
c
a
b
SiPent2
S
S
5d (1.0 equiv)
d
Si
Si*
S
Br
S
S
7, 89%
8, 90%
c
75 °C, 10 h
NEt
Ph2N
Oct
S
Oct
S
Si*
14, 80%
S
S
9, 82%
Scheme 4. Linear synthesis of oligoarenylsilane. Reagents
and conditions: (a) TsOH¢H2O (2 mol %), MeOH-CH2Cl2
(1:1), rt, overnight; (b) [(allyl)PdCl]2 (1 or 5 mol % Pd),
RuPhos (2 or 11 mol %), CuI (3 or 5 mol %), K2CO3
(2.5 equiv), THF-DMF, 75 °C; (c) DIBAL-H (1.1 equiv),
CH2Cl2, ¹78 °C, 2 h; (d) PdCl2(dppf)¢CH2Cl2 (5 mol %),
CuI (5 mol %), K2CO3 (2.5 equiv), THF-DMF, 75 °C, 24 h.
d
S
S
Si*
Br
S
S
S
S
10, 90%
50 °C, 5 h
t-BuMe2Si
Si
c
1j
Si*
silicon residue 2 in good yield (Entry 1). (E)-Styrylsilane 1i
participates in the coupling reaction in the absence of CuI to
give (E)-phenylenevinylene substructures (Entries 12 and 13).
The deprotection and subsequent cross-coupling reaction
of the silylated biaryls thus obtained proceeded successfully
(Schemes 3 and 4). For example, the deprotection of 6gf under
acidic conditions gave silylbithiophene 7 with a free hydroxy
group in 89% yield, whereas lithiation of 6gf with n-BuLi
followed by bromination with 1,2-dibromo-1,1,2,2-tetrafluoro-
ethane gave 5-bromo-5¤-silyl-2,2¤-bithiophene 8 in 90% yield
(Scheme 3). The observed high stability of silylated bithio-
phenes 7 and 8 under the acidic and basic transformations
is remarkable. The coupling reaction of 7 and 8 proceeds
successfully to give silylated quaterthiophene 9 that was
subjected to bromination leading to 10 followed by a
subsequent cross-coupling with 2,5-disilyl-substituted thio-
phene 1j to give unsymmetrically disilylated quinquethiophene
11, which would enjoy potential application to two-photon
absorption materials.22 In addition, silylated biaryls could be
transformed to linear silylated oligoarenes. Thus, three depro-
tection-cross-coupling sequences starting with 6hc led to
³-conjugated protected oligoarenylsilane 14 in an efficient
manner (Scheme 4).
S
S
t-BuMe2Si
S
S
11, 80%
Scheme 3. Convergent synthesis of disilylated quinquethio-
phene. Reagents and conditions: (a) PPTS (20 mol %),
MeOH, 40 °C, 2 h; (b) n-BuLi, TMEDA, THF, ¹40 °C to
rt, 1 h, then BrCF2CF2Br, ¹40 °C, 1 h; (c) PdCl2(dppf)¢
CH2Cl2 (3 or 5 mol %), CuI (9 or 5 mol %), K2CO3 (2.5
equiv), THF-DMF; (d) n-BuLi, TMEDA, THF, ¹78 °C,
5 min, then BrCF2CF2Br, ¹40 °C, 1 h.
Therefore, we prepared aryl bromides bearing an O-
protected silyl group 5a-5f starting simply from the corre-
sponding dibromides and examined their coupling reaction
with the arylsilanes (Table 4). The reaction conditions devel-
oped for the biaryl synthesis worked perfectly well to give
a wide variety of ³-conjugated molecules having phenyl,
phenylethenyl, fluorenyl, sila-fluorenyl, carbazolyl, and
thienyl motifs with the silyl group at their terminal arenes
in good yields (Entries 1-11). Both THP and acetyl protec-
tions tolerated these reaction conditions. Gram-scale synthesis
(Entries 1, 4, and 11) is used to allow an easy isolation of

J. Chen et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
559
Table 4. Synthesis of Silylated Arenesa)
[(allyl)PdCl]2 (1 mol % Pd)
RuPhos (2.1 mol %)
CuI (3 mol %)
K2CO3 (2.5 equiv)
THPO
AcO
Si** =
π
+
π
+ 2
Si*/Si**
π
π
Si
Br
Si*/Si**
Si* =
Si
Me2
Si
Me2
THF−DMF (3:1), 75 °C
6
1
5
1.2 equiv
Entry
1c)
1
5
Time/h
Product
Yield of 6/%b)
88 (6ha)d)
Ph2N
Ph2N
Br
Ph2N
7
Si*
Si
1h
5a
Si*
Br
2
1h
1h
22
17
93 (6¤ha)
93 (6hb)
Si**
5'a
Si**
Ph2N
Br
3
Si*
Si*
5b
Si*
Oct Oct
Oct Oct
4e)
1h (1.5 equiv)
1h (1.5 equiv)
30
24
93 (6hc)
82 (6hd)
Ph2N
Br
Si*
5c
Pent2
Si
Pent2
Si
Ph2N
5f),g)
Br
Si*
Si*
5d
Ph2N
Br
Br
Si*
Si*
6
7
1h
22
18
85 (6he)
94 (6¤he)
N
Et
5e
N
Et
Ph2N
Si**
Si**
1h (1.5 equiv)
N
Et
5'e
N
Et
S
Br
Br
Si*
Ph2N
Ph2N
8h)
1h
1h
8
7
81 (6hf)
81 (6¤hf)
S
S
Si*
5f
S
Si**
9h)
Si**
5'f
10h),i),j)
1g
1g
5a
6
96 (6ga)
S
S
Si*
Si*
S
11e),i)
12k)
5f
6
7
96 (6gf)
90 (6ia)
Ph
Ph
Si
5a
1i
Si*
Ph
13k)
1i
5b
22
90 (6ib)
Si*
a) Reactions were performed on a 1.0-mmol scale unless otherwise noted. b) Isolated yields based on 5. c) Run on a 10-mmol scale.
d) 2 was isolated in 86% based on conversion of 1h (88%). e) Run on a 20-mmol scale. f) Run on a 0.10-mmol scale. g) Run with
5 mol % Pd. h) Run with 3 mol % Pd. i) Run with PdCl2(dppf)¢CH2Cl2 as a catalyst. j) Run at 50 °C. k) Run without CuI.

560
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
Synthesis of Biaryls and Oligoarenes
Table 5. Synthesis of Disilylated Arenes
cat. Pd (5 mol % Pd)
CuI (5 mol %)
K2CO3 (1.25 mmol)
π
+
π
+ 2
π
π
**Si
Si
Br
Si*
**Si
Si*
THF−DMF (3:1), 50 °C
16
5
17
(0.50 mmol)
(0.60 mmol)
Entry
1
16
5
Pd cat.
Time/h
Product
Yield of 17/%a)
87 (17ab)
**Si
**Si
S
[(allyl)PdCl]2/
RuPhos (10.5 mol %)
S
5b
7
Si
16a
Si*
Oct Oct
[(allyl)PdCl]2/
RuPhos (10.5 mol %)
2
3
16a
5c
6
6
84 (17ac)
86 (17ad)
**Si
Si*
Si*
S
Pent2
Si
[(allyl)PdCl]2/
RuPhos (10.5 mol %)
16a
16a
5d
**Si
**Si
S
S
[(allyl)PdCl]2/
RuPhos (10.5 mol %)
4
5e
6
Si*
86 (17ae)
N
Et
Si
**Si
**Si
5b)
5b PdCl2(dppf)¢CH2Cl2
5c PdCl2(dppf)¢CH2Cl2
6
9
82 (17bb)
80 (17bc)
S
S
**Si
16b
Si*
Oct Oct
6
16b
Si*
Si*
S
S
Pent2
Si
7
16b
16b
5d PdCl2(dppf)¢CH2Cl2
5e PdCl2(dppf)¢CH2Cl2
6
8
82 (17bd)
81 (17be)
**Si
**Si
Si*
S
8b)
N
Et
a) Isolated yields based on 7. b) Run with 1 mol % CuI.
We next targeted oligoarenes bearing two silyl groups with
orthogonally O-protecting groups (Table 5). This was initiated
by the synthesis of disilylated biaryls 16a and 16b, which
were readily obtained by the cross-coupling reactions of 1,4-
disilylated benzene 15a and 2,5-disilylated thiophene 15b with
5¤f and 5¤a followed by deprotection, respectively (Scheme 5).
Both 16a and 16b cross-coupled with silylated aryl bromides
5b-5e in good yields to give a variety of oligoarenes 17 having
two differently O-protected silyl groups at their terminal arene
rings. Furthermore, cross-coupling of oligoarenes having three
silyl groups was envisioned by employing a silyl ether as the
third type of protection. Trisilylbenzene 20 was prepared first
through a sequential silylation of 1,3,5-tribromobenzene fol-
lowed by O-protection (Scheme 6). The cross-coupling of 20
with 5¤a gave 21¤ in 70% yield (Scheme 7). The t-BuPh2Si
protection in 21¤ was exclusively removed by TBAF to give 21
with other silyl and O-protecting groups intact, and the subse-
quent cross-coupling with 2-bromo-5-silylthiophene 5¤¤f afford-
ed 22¤. Finally, upon treatment of 22¤ with an acid catalyst to
remove the THP group, resultant 22 underwent the cross-
coupling with 5c to give trisilylated oligoarene 23 with three
orthogonal O-protecting groups at the respective arene terminus.
Conclusion
In summary, we have demonstrated that 2-(hydroxymethyl)-
phenyl-substituted arylsilanes serve as efficient reagents for

J. Chen et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
561
R
Si
5'a (1.2 equiv)
20
a (27 h)
Si*
*Si
15a (6.0 mmol)
**Si
a
S
+
Si**
5'f
R = Si***: 21' (70%)
Si: 21 (77%)
R
b
(7.2 mmol)
R = Si*: 16'a (87%)
Si: 16a (92%)
S
Br
Si***
b
5''f (1.2 equiv) a (19 h)
***Si
S
Si
Si*
S
t-BuPh2SiO
Si*** =
15b (1.0 mmol)
c
Si
+
R
Me2
S
5'a
(1.2 mmol)
**Si
R = Si*: 16'b
Si: 16b (72% for 2 steps)
R
b
Si**
***Si
R = Si*: 22' (89%)
Si: 22 (80%)
c
Scheme 5. Synthesis of disilylated biaryls 16a and 16b.
Reagents and conditions: (a) [(allyl)PdCl]2 (3 mol % Pd),
RuPhos (6.3 mol %), CuI (9 mol %), K2CO3 (2.5 equiv),
THF-DMF, 75 °C, 8 h; (b) PPTS (20 mol %), MeOH,
40 °C, 3 or 6 h; (c) PdCl2(dppf)¢CH2Cl2 (3 mol %), CuI
(9 mol %), K2CO3 (2.5 equiv), THF-DMF, 75 °C, 6 h.
S
5c (1.2 equiv)
d
Oct
Oct
Si**
*Si
23, 73%
Scheme 7. Linear synthesis of trisilylated oligoarene. Re-
agents and conditions: (a) [(allyl)PdCl]2 (5 mol % Pd),
RuPhos (11 mol %), CuI (5 mol %), K2CO3 (2.5 equiv),
THF-DMF, 50 °C; (b) TBAF (2.0 equiv), THF, rt, 1 h;
(c) PPTS (20 mol %), MeOH-THF, rt, overnight; (d)
[(allyl)PdCl]2 (10 mol % Pd), RuPhos (10 mol %), CuI
(5 mol %), K2CO3 (2.5 equiv), THF-DMF, 50 °C, 24 h.
Br
Br
a
Br
Br
R
Br
R = Si: 18 (98%)
Si*: 18' (81%)
b
c
Si***
R
under a nitrogen or argon atmosphere. Flash column chroma-
tography was performed using Kanto Chemical silica gel
(spherical, 40-50 ¯m). Analytical thin layer chromatography
(TLC) was performed on Merck Kieselgel 60 F254 (0.25 mm)
plates. Visualization was accomplished with UV light (254 nm)
and/or an aqueous alkaline KMnO4 solution followed by
heating.
c
*Si
Si
*Si
Br
20, 81%
R = Si: 19 (92%)
Si***: 19' (96%)
d
Scheme 6. Synthesis of trisilylated benzene 20. Reagents
and conditions: (a) n-BuLi, Et2O, ¹78 °C, 2 h, then 2,
¹78 °C to rt; (b) 3,4-dihydro-2H-pyran, PPTS (10 mol %),
CH2Cl2, rt, 5 h; (c) 2, t-BuLi, Et2O, ¹78 °C to rt, overnight;
(d) t-BuPh2Si-Cl, imidazole, DMF, rt, 3 h.
Apparatus. Proton and carbon nuclear magnetic resonance
spectra (1H and 13C NMR) were recorded on a Varian Mercury
400 (1H NMR, 400 MHz; 13C NMR 101 MHz) spectrometer
with solvent resonance as the internal standard (1H NMR,
1
CHCl3 at 7.26 ppm; 13C NMR, CDCl3 at 77.0 ppm). H NMR
palladium/copper-catalyzed biaryl synthesis. Newly developed
reaction conditions as well as arylsilane reagents allow a
general substrate scope for a silicon-based approach to
producing biaryls with excellent chemoselectivity and higher
yields of recoverable and reusable cyclic silyl ether. A simple
switch of the arylsilane reactivity by O-protection is demon-
strated to be highly useful and efficient to access a wide variety
of silylated oligoarenes. Future studies will focus on the
development of more practical protocols for the iterative cross-
coupling sequence involving a one-pot deprotection-cross-
coupling system as well as applications to solid-phase syn-
thesis.
data are reported as follows: chemical shift, multiplicity (s =
singlet, d = doublet, t = triplet, q = quartet, quint = quintet,
sext = sextet, sept = septet, br = broad, m = multiplet), cou-
pling constants (Hz), and integration. Melting points were
determined using a YANAKO MP-500D. Infrared spectra (IR)
were recorded on a Shimadzu FTIR-8400 spectrometer and
are reported in cm¹1. Elemental analyses were performed by
the Elementary Analysis Center of Kyoto University. High-
resolution mass spectra were obtained with a JEOL JMS-700
(EI), JEOL JMS-HX110A (FAB), or Bruker Daltonics Autoflex
III (MALDI) spectrometer. Preparative recycling gel perme-
ation chromatography (GPC) was performed with a JAI LC-
908 chromatograph equipped with JAIGEL-1H and -2H using
chloroform as an eluent. GC analysis was performed on a
Shimadzu GC 2014 equipped with an ENV-1 column (Kanto
Chemical, 30 m © 0.25 mm, pressure = 31.7 kPa, detector =
Experimental
General.
All manipulations of oxygen- and moisture-
sensitive materials were conducted with Schlenk techniques

562
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
Synthesis of Biaryls and Oligoarenes
Preparation of 1,1-Diisopropyl-2-oxa-1-silaindan (2¤).
FID, 290 °C) with helium gas as a carrier.
A
Chemicals. Unless otherwise noted, commercially avail-
able liquid chemicals were distilled and degassed before use.
Solid chemicals were used without purification. Anhydrous
THF was purchased from Kanto Chemical and degassed by
purging vigorously with argon for 20 min and further purified
by passage through activated alumina under positive argon
pressure as described by Grubbs et al.23 Anhydrous DMF was
purchased from Nacalai Tesque and used as received. RuPhos
was prepared according to the Buchwald protocol.18 Aryl[2-
(hydroxymethyl)phenyl]dimethylsilanes 114 and 4-(4,4,5,5-
1.6 M n-BuLi solution in hexane (12.7 mL, 20 mmol) was
added to a solution of 2-(tetrahydro-2H-pyran-2-yloxymethyl)-
bromobenzene (5.0 g, 18.4 mmol) in THF (3.8 mL) over 5 min
at ¹78 °C, and the resulting solution was stirred for 2 h before
the addition of chlorodiisopropylsilane (3.3 g, 22 mmol) at
¹78 °C. The mixture was allowed to warm to rt overnight
before dilution with diethyl ether. The whole was washed with
a saturated NaHCO3 aqueous solution, water, and then brine,
and the organic layer was dried over anhydrous MgSO4 and
concentrated in vacuo. The residue was dissolved in MeOH
(74 mL), and p-toluenesulfonic acid monohydrate (175 mg,
0.92 mmol) was added portionwise at rt. The mixture was
stirred overnight before concentration in vacuo. The residue
was distilled to give the title compound (4.1 g, 82%) as a
colorless oil (bp 75 °C at 3.0 mmHg). 1H NMR (400 MHz,
CDCl3): ¤ 7.57 (d, J = 7.3 Hz, 1H), 7.39 (t, J = 7.4 Hz, 1H),
7.31-7.21 (m, 2H), 5.15 (s, 2H), 1.25 (sept, J = 7.3 Hz, 2H),
1.04 (d, J = 7.3 Hz, 6H), 1.01 (d, J = 7.3 Hz, 6H); 13C NMR
(101 MHz, CDCl3): ¤ 150.5, 132.0, 131.6, 129.3, 126.4, 121.4,
72.5, 17.1, 13.2; IR (neat): 2941, 2864, 1464, 1443, 1067,
1049, 880, 781, 746, 716, 667, 642 cm¹1; Anal. Calcd for
C13H20OSi: C, 70.85; H, 9.15%. Found: C, 70.75; H, 8.92%.
Preparation of [2-(Hydroxymethyl)phenyl](diisopropyl)-
phenylsilane (1¤a). To a solution of 2¤ (11.0 g, 50 mmol) in
THF (125 mL) was added a 1.07 M solution of phenylmagne-
sium bromide in THF (51 mL, 55 mmol) over 30 min at 0 °C,
and the resulting mixture was stirred at rt overnight. The reac-
tion was quenched with a saturated NH4Cl aqueous solution at
0 °C, and the aqueous layer was extracted with diethyl ether.
The combined organic layers were washed with water and then
brine, dried over anhydrous MgSO4, and concentrated in vacuo.
The residue was purified by flash chromatography on silica gel
to give the title compound (13.5 g, 90%) as a colorless solid
(mp 119.0-119.6 °C), Rf = 0.69 (hexane-ethyl acetate = 2:1).
1H NMR (400 MHz, CDCl3): ¤ 7.63-7.55 (m, 2H), 7.52-7.29
(m, 7H), 4.40 (d, J = 5.6 Hz, 2H), 1.67 (sept, J = 7.2 Hz, 2H),
1.38 (t, J = 5.8 Hz, 1H), 1.00 (d, J = 7.2 Hz, 6H), 0.98 (d,
J = 7.2 Hz, 6H); 13C NMR (101 MHz, CDCl3): ¤ 147.6, 136.7,
134.9, 134.8, 130.9, 129.6, 129.1, 128.6, 127.7, 126.5, 65.6,
18.0, 17.9, 10.7; IR (KBr): 3364, 2953, 2924, 2889, 2862,
1636, 1462, 1427, 1381, 1364, 1313, 1277, 1234, 1198, 1123,
1105, 1078, 1015, 995, 918, 878, 816, 758, 745, 708, 687, 656,
615, 517, 488, 459 cm¹1; Anal. Calcd for C19H26OSi: C, 76.45;
H, 8.78%. Found: C, 76.24; H, 8.96%.
tetramethyl-1,3,2-dioxaborolan-2-yl)bromobenzene
(3d)24
were prepared following a reported procedure. All the spectral
data of biaryls shown in Tables 1-3 and eq 3 agreed perfectly
with those reported previously by ourselves, unless otherwise
described below.10 Data for silylated oligoarenes shown in
Table 4, Schemes 3 and 4 have been reported in a previous
communication.16
Preparation of (4-Bromophenyl)tributylstannane (3c).25
To a solution of 1,4-dibromobenzene (3.5 g, 15 mmol) in THF
(30 mL) was added a 1.6 M solution of n-BuLi in hexane
(9.4 mL, 15 mmol) over 1 h at ¹78 °C, and the resulting
mixture was stirred at ¹78 °C for an additional 1 h. Tributyl-
chlorostannane (4.9 g, 15 mmol) was added at ¹78 °C, and then
the resulting mixture was stirred at ¹78 °C for 1 h. The reaction
was quenched with a saturated NH4Cl aqueous solution, and
the aqueous layer was extracted with diethyl ether. The
combined organic layers were washed with water and then
brine, and dried over anhydrous MgSO4. After concentration in
vacuo, the residue was purified by flash chromatography on
silica gel to give the title compound (5.6 g, 83%) as a colorless
1
oil, Rf = 0.69 (hexane). H NMR (400 MHz, CDCl3): ¤ 7.48-
7.42 (m, 2H), 7.38-7.24 (m, 2H), 1.63-1.41 (m, 6H), 1.33
(sext, J = 7.3 Hz, 6H), 1.15-0.95 (m, 6H), 0.89 (t, J = 7.3 Hz,
9H); 13C NMR (101 MHz, CDCl3): ¤ 140.6, 137.9, 131.0,
122.7, 29.0, 27.3, 13.7, 9.6.
Preparation of [2-(Hydroxymethyl)phenyl]dimethyl(4-
methylphenyl)silane (1b). To a solution of 1,1-dimethyl-2-
oxa-1-silaindan (2,14a 7.5 g, 46 mmol) in THF (180 mL) was
added a 0.5 M solution of p-tolylmagnesium bromide in diethyl
ether (100 mL, 50 mmol) over 30 min at 0 °C. The resulting
mixture was stirred at rt overnight. The reaction was quenched
with a saturated NH4Cl aqueous solution at 0 °C, and the
aqueous layer was extracted with diethyl ether. The combined
organic layers were washed with water and then brine, dried
over anhydrous MgSO4, and concentrated in vacuo. The residue
was purified by flash chromatography on silica gel to give the
title compound (9.7 g, 83%) as a colorless solid (mp 55.6-
56.5 °C) Rf = 0.19 (hexane-ethyl acetate = 5:1). 1H NMR
(400 MHz, CDCl3): ¤ 7.48-7.37 (m, 4H), 7.39 (d, J = 7.5 Hz,
1H), 7.32 (td, J = 7.0, 2.0 Hz, 1H), 7.18 (dd, J = 8.1, 0.5 Hz,
2H), 4.54 (d, J = 6.0 Hz, 2H), 2.36 (s, 3H), 1.28 (t, J = 6.0 Hz,
1H), 0.61 (s, 6H); 13C NMR (101 MHz, CDCl3): ¤ 146.3, 139.0,
136.0, 135.3, 135.1, 133.7, 129.8, 128.8, 128.1, 126.9, 65.3,
21.6, ¹0.9; IR (KBr): 3285, 3059, 3030, 3009, 2951, 2920,
1599, 1460, 1435, 1408, 1391, 1258, 1248, 1200, 1128, 1105,
1078, 1038, 1018, 826, 797, 775, 756, 745, 716, 689, 660,
602, 500, 490, 430, 407 cm¹1; Anal. Calcd for C16H20OSi:
C, 74.95; H, 7.86%. Found: C, 75.00; H, 7.93%.
Cross-Coupling Reaction of 1 with Aryl Bromides.
A
General Procedure: To a mixture of 1 (1.2-1.5 mmol),
K2CO3 (0.35 g, 2.5 mmol), [(allyl)PdCl]2 (1.8 mg, 5.0 ¯mol),
RuPhos (9.8 mg, 21 ¯mol), and CuI (5.7 mg, 30 ¯mol) in DMF
(0.8 mL) and THF (2.2 mL) was added an aryl bromide
(1.0 mmol), and the resulting mixture was stirred at 75 °C.
After the time specified in Tables 1 and 2, the mixture was
filtered through a Florisil pad, diluted with diethyl ether,
washed with water and then brine, and dried over anhydrous
MgSO4. Concentration in vacuo followed by flash chromatog-
raphy on silica gel afforded the corresponding biaryl in a yield
listed in Tables 1 and 2. The yield of cyclic silyl ether 2
was determined by GC analysis using nonane as an internal
standard.

J. Chen et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
563
(Biphenyl-4-yl)tributylstannane
(4ac,
Entry 3
of
RuPhos (9.8 mg, 21 ¯mol), and CuI (5.7 mg, 30 ¯mol) in DMF
(0.8 mL) and THF (2.2 mL) was added an aryl chloride
(1.0 mmol), and the resulting mixture was stirred at 50 °C.
After the time specified in Table 3, the mixture was filtered
through a Florisil pad, diluted with diethyl ether, washed with
water and then brine, and dried over anhydrous MgSO4.
Concentration in vacuo followed by flash chromatography on
silica gel afforded the corresponding biaryl in a yield listed in
Table 3. The yield of cyclic silyl ether 2¤ was determined by
GC analysis using tridecane as an internal standard.
Table 1);26
A colorless oil, Rf = 0.35 (hexane). 1H NMR
(400 MHz, CDCl3): ¤ 7.63-7.47 (m, 6H), 7.44 (t, J = 7.8 Hz,
2H), 7.34 (t, J = 7.4 Hz, 1H), 1.68-1.46 (m, 6H), 1.35 (sext,
J = 7.3 Hz, 6H), 1.18-1.00 (m, 6H), 0.91 (t, J = 7.3 Hz, 9H);
13C NMR (101 MHz, CDCl3): ¤ 141.3, 140.9, 140.7, 136.9,
128.7, 127.15, 127.09, 126.6, 29.1, 27.4, 13.7, 9.6.
3-Aminobiphenyl (4am, Entry 13 of Table 1);27 An off-
white solid (mp 29.5-30.6 °C), Rf = 0.19 (hexane-ethyl ace-
tate = 5:1). 1H NMR (400 MHz, CDCl3): ¤ 7.58-7.54 (m, 2H),
7.45-7.39 (m, 2H), 7.33 (tt, J = 6.6, 1.4 Hz, 1H), 7.23 (t,
J = 7.8 Hz, 1H), 7.00 (ddd, J = 4.5, 1.6, 0.9 Hz, 1H), 6.92 (t,
J = 2.0 Hz, 1H), 6.69 (ddd, J = 7.9, 2.4, 0.9 Hz, 1H), 3.75 (br,
2H); 13C NMR (101 MHz, CDCl3): ¤ 146.5, 142.2, 141.2,
129.5, 128.5, 127.1, 127.0, 117.6, 114.0, 113.8.
Preparation of {Dimethyl[2-(tetrahydro-2H-pyranoxy-
methyl)phenyl]silyl}-4-{[2-(hydroxymethyl)phenyl]dimeth-
ylsilyl}benzene (15a). To a solution of 5a (14.4 g, 36 mmol)
in THF (80 mL) was added a 1.6 M solution of n-BuLi in
hexane (24 mL, 38 mmol) at ¹78 °C, and the resulting mixture
was stirred at ¹78 °C for 1 h. To this was added 2 (5.7 g,
35 mmol) at ¹78 °C, and the resulting mixture was stirred
overnight during which time the mixture was allowed to warm
to rt. The entirety was diluted with diethyl ether and to it was
added water. The organic layer was dried over anhydrous
MgSO4 and then concentrated in vacuo. The residue was
purified by flash chromatography on silica gel to give the title
compound (14.4 g, 82%) as a colorless viscous oil, Rf = 0.18
3-Hydroxymethylbiphenyl (4an, Entry 14 of Table 1);28
A colorless solid (mp 49.1-49.9 °C), Rf = 0.23 (hexane-ethyl
1
acetate = 3:1). H NMR (400 MHz, CDCl3): ¤ 7.63-7.57 (m,
3H), 7.54 (dt, J = 7.7, 1.5 Hz, 1H), 7.48-7.42 (m, 3H), 7.39-
7.33 (m, 2H), 4.78 (s, 2H), 1.77 (s, 1H); 13C NMR (101 MHz,
CDCl3): ¤ 141.4, 141.2, 140.8, 128.9, 128.6, 127.2, 127.0,
126.4, 125.72, 125.66, 65.4.
Cross-Coupling Reaction of 1a with 3d (Entry 4 of
Table 1). To a solution of 1a (0.36 g, 1.5 mmol) in THF
(1.1 mL) was added a 1.6 M solution of n-BuLi in hexane (0.94
mL, 1.5 mmol) at 0 °C, and the resulting mixture was stirred for
5 min. To the mixture were added sequentially DMF (0.4 mL),
[(allyl)PdCl]2 (1.8 mg, 5.0 ¯mol), RuPhos (9.8 mg, 21 ¯mol),
CuI (5.7 mg, 30 ¯mol), and 3d (0.28 g, 1.0 mmol) at rt. The
resulting mixture was stirred at 75 °C for 11 h before filtration
through a Florisil pad. The filtrate was diluted with diethyl
ether, washed with water and then brine, dried over anhydrous
MgSO4, and concentrated in vacuo. The residue was purified
by flash chromatography on silica gel followed by preparative
GPC to give 4ad (0.23 g, 81%) as a colorless oil, Rf = 0.23
1
(hexane-ethyl acetate = 5:1). H NMR (400 MHz, CDCl3): ¤
7.56 (dd, J = 14.8, 7.3 Hz, 2H), 7.51-7.36 (m, 8H), 7.33-7.23
(m, 2H), 4.55 (d, J = 12.3 Hz, 1H), 4.50 (d, J = 5.9 Hz, 2H),
4.40 (t, J = 3.2 Hz, 1H), 4.29 (d, J = 12.3 Hz, 1H), 3.77-3.67
(m, 1H), 3.35 (td, J = 11.2, 4.1 Hz, 1H), 1.90 (t, J = 5.9 Hz,
1H), 1.85-1.72 (br m, 1H), 1.64-1.40 (m, 5H), 0.60 (s, 6H),
0.58 (s, 6H); 13C NMR (101 MHz, CDCl3): ¤ 146.7, 144.0,
139.7, 139.6, 135.5, 135.2, 135.1, 133.3, 133.0, 129.7, 129.5,
127.9, 127.2, 126.61, 126.60, 97.5, 68.7, 64.9, 61.6, 30.4,
25.5, 19.1, ¹0.9, ¹1.10, ¹1.15, ¹1.2 (a signal for sp2-carbon
overlaps with others); IR (neat): 3443, 3049, 2993, 2951, 2897,
2872, 1925, 1823, 1589, 1564, 1466, 1454, 1435, 1410, 1381,
1350, 1323, 1285, 1250, 1200, 1182, 1132, 1078, 1055, 1024,
976, 907, 868, 835, 814, 773, 754, 689, 654, 606 cm¹1; Anal.
Calcd for C29H38O3Si2: C, 70.97; H, 7.80%. Found: C, 70.68;
H, 7.87%.
1
(hexane-ethyl acetate = 20:1). H NMR (400 MHz, CDCl3): ¤
7.90 (d, J = 8.1 Hz, 2H), 7.66-7.60 (m, 4H), 7.48-7.43 (m,
2H), 7.39-7.34 (m, 1H), 1.39 (s, 12H); 13C NMR (101 MHz,
CDCl3): ¤ 143.7, 140.8, 135.1, 128.6, 127.4, 127.1, 126.3,
83.8, 25.0; IR (neat): 3028, 2978, 2928, 1609, 1398, 1362,
1321, 1302, 1273, 1259, 1215, 1144, 1092, 1040, 1022, 1009,
962, 860, 841, 768, 735, 696, 658 cm¹1; Anal. Calcd for
C18H21BO2: C, 77.17; H, 7.55%. Found: C, 77.41; H, 7.27%.
Gram-Scale Cross-Coupling Reaction of 1a with 3p
(Entry 16 of Table 1). To a mixture of 1a (6.3 g, 26 mmol),
K2CO3 (6.9 g, 50 mmol), [(allyl)PdCl]2 (37 mg, 0.100 mmol),
RuPhos (184 mg, 0.40 mmol), and CuI (114 mg, 0.60 mmol) in
DMF (10 mL) and THF (20 mL) was added 3p (3.4 g,
20 mmol), and the resulting mixture was stirred at 75 °C for
14 h before filtration through a Florisil pad. The filtrate was
diluted with diethyl ether, washed with water and then brine,
dried over anhydrous MgSO4, and concentrated. The residue
was distilled under vacuum (45 °C at 1.0 mmHg) to give 2
[3.1 g, 91% (ca. 90% purity)]; the residue was further purified
by flash chromatography on silica gel (hexane-ethyl acetate =
13:1 as an eluent) to give 3-methylbiphenyl (4ap, 2.9 g, 87%).
Preparation of 2-{Dimethyl[2-(tetrahydro-2H-pyranoxy-
methyl)phenyl]silyl}-5-{[2-(hydroxymethyl)phenyl]dimeth-
ylsilyl}thiophene (15b). To a solution of 5f (20 g, 49 mmol)
in THF (29 mL) was added a 1.6 M solution of n-BuLi in
hexane (32 mL, 52 mmol) at ¹78 °C, and the resulting mixture
was stirred at ¹40 °C for 1 h. To this was added magnesium
bromide ethyl etherate (13.2 g, 52 mmol) at ¹40 °C, and the
mixture was stirred for 0.5 h before addition of 2 (8.0 g,
49 mmol) all at the same temperature. The resulting mixture
was allowed to warm to rt overnight with stirring, and diluted
with diethyl ether. Water was added, and the organic layer was
separated, dried over anhydrous MgSO4, and concentrated in
vacuo. The residue was purified by flash chromatography on
silica gel to afford the title compound (23 g, 95%) as a brown
1
viscous oil, Rf = 0.15 (hexane-ethyl acetate = 5:1). H NMR
(400 MHz, CDCl3): ¤ 7.61-7.38 (m, 6H), 7.34-7.24 (m, 4H),
4.64 (d, J = 12.3 Hz, 1H), 4.61 (d, J = 5.3 Hz, 2H), 4.50 (t,
J = 3.3 Hz, 1H), 4.37 (d, J = 12.3 Hz, 1H), 3.82-3.71 (m, 1H),
3.44-3.36 (m, 1H), 2.20 (br s, 1H), 1.87-1.73 (m, 1H), 1.69-
1.43 (m, 5H), 0.66 (s, 6H), 0.64 (s, 6H); 13C NMR (101 MHz,
Cross-Coupling Reaction of 1¤a with Aryl Chlorides.
General Procedure: To a mixture of 1¤a (0.45 g, 1.5 mmol),
K2CO3 (0.35 g, 2.5 mmol), [(allyl)PdCl]2 (1.8 mg, 5.0 ¯mol),
A

564
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
Synthesis of Biaryls and Oligoarenes
CDCl3): ¤ 146.8, 144.8, 144.7, 143.9, 136.4, 136.3, 135.5,
135.0, 134.9, 134.8, 129.9, 129.7, 128.1, 127.3, 126.68,
126.65, 97.6, 68.7, 64.9, 61.7, 30.5, 25.5, 19.1, 0.4, 0.2; IR
(neat): 3445, 3055, 2951, 2872, 1589, 1564, 1487, 1435, 1410,
1350, 1250, 1202, 1126, 1078, 1005, 976, 907, 835, 808, 777,
754, 691, 652 cm¹1; Anal. Calcd for C27H36O3SSi2: C, 65.27;
H, 7.30%. Found: C, 65.16; H, 7.50%.
K2CO3 (0.35 g, 2.5 mmol), PdCl2(dppf)¢CH2Cl2 (24 mg, 30
¯mol), and CuI (17.1 mg, 90 ¯mol) in DMF (0.8 mL) and THF
(2.2 mL) was added 5¤a (1.2 mmol), and the resulting mixture
was stirred at 75 °C for 6 h. The mixture was filtered through a
Florisil pad, and the filtrate was diluted with diethyl ether and
washed with water and then brine. The organic layer was dried
over anhydrous MgSO4 and concentrated in vacuo. The residue
was dissolved in MeOH (5 mL) and treated with PPTS (50 mg,
0.20 mmol) at rt for 6 h. After concentration in vacuo, the
residue was purified by flash chromatography on silica gel to
give the title compound (0.38 g, 72%) as a colorless viscous oil,
Rf = 0.08 (hexane-ethyl acetate = 5:1). 1H NMR (400 MHz,
CDCl3): ¤ 7.63-7.55 (m, 4H), 7.52-7.29 (m, 9H), 7.23 (d,
J = 3.5 Hz, 1H), 5.00 (s, 2H), 4.69 (d, J = 5.7 Hz, 2H), 1.93 (s,
3H), 1.57 (br t, J = 5.6 Hz, 1H), 0.70 (s, 6H), 0.64 (s, 6H);
13C NMR (101 MHz, CDCl3): ¤ 170.4, 150.1, 146.4, 141.1,
138.5, 137.7, 136.9, 136.2, 135.6, 135.23, 135.16, 134.6,
134.4, 130.1, 129.7, 129.5, 128.0, 127.5, 127.0, 125.2, 124.6,
66.6, 65.3, 21.0, 0.3, ¹0.9; IR (neat): 3441, 3055, 3013, 2955,
2899, 1736, 1593, 1546, 1543, 1524, 1462, 1433, 1414, 1381,
1362, 1319, 1300, 1256, 1236, 1163, 1126, 1111, 1078, 1026,
995, 947, 924, 876, 835, 812, 777, 756, 729, 689, 660,
638 cm¹1; Anal. Calcd for C30H34O3SSi2: C, 67.88; H, 6.46%.
Found: C, 68.10; H, 6.58%.
Cross-Coupling Reaction of 16a with 5b-5e. A General
Procedure: To a mixture of 16a (0.27 g, 0.50 mmol), K2CO3
(0.17 g, 1.25 mmol), [(allyl)PdCl]2 (4.3 mg, 12 ¯mol), RuPhos
(25 mg, 53 ¯mol), and CuI (4.8 mg, 25 ¯mol) in DMF (0.4 mL)
and THF (1.1 mL) was added 5b-5e (0.60 mmol), and the
resulting mixture was stirred at 50 °C for 6-7 h before filtration
through a Florisil pad. The filtrate was diluted with diethyl
ether and washed with water and then brine. The organic layer
was dried over anhydrous MgSO4 and concentrated in vacuo.
The residue was purified by flash chromatography on silica gel
to give 17ab-17ae in a yield listed in Entries 1-4 of Table 5.
(E)-2-{[2-(Acetoxymethyl)phenyl]dimethylsilyl}-5-[4¤-(2-
{dimethyl[2-(tetrahydro-2H-pyranoxymethyl)phenyl]silyl}-
ethenyl)biphenyl-4-yl]thiophene (17ab, Entry 1 of Table 5);
A yellow viscous oil, Rf = 0.22 (hexane-ethyl acetate = 5:1).
1H NMR (400 MHz, CDCl3): ¤ 7.69-7.56 (m, 8H), 7.55-7.48
(m, 3H), 7.47-7.27 (m, 6H), 7.23 (d, J = 3.5 Hz, 1H), 6.97 (d,
J = 19.0 Hz, 1H), 6.70 (d, J = 19.2 Hz, 1H), 5.11 (s, 2H), 4.88
(d, J = 11.9 Hz, 1H), 4.67 (t, J = 3.5 Hz, 1H), 4.63 (d, J = 11.9
Hz, 1H), 3.93-3.84 (m, 1H), 3.53-3.44 (m, 1H), 2.01 (s, 3H),
1.91-1.79 (m, 1H), 1.77-1.43 (m, 5H), 0.77 (s, 6H), 0.52 (s,
6H); 13C NMR (101 MHz, CDCl3): ¤ 170.4, 149.9, 144.1,
143.8, 141.1, 139.8, 139.5, 137.8, 137.2, 136.5, 136.4, 135.4,
134.9, 133.1, 129.9, 129.5, 129.4, 128.4, 128.1, 127.6, 127.1,
126.84, 126.76, 126.2, 124.4, 97.9, 68.9, 66.6, 62.2, 30.7, 25.6,
21.0, 19.5, 0.2, ¹1.0, ¹1.1 (two signals for sp2-carbons overlap
with others); IR (neat): 3055, 2916, 2849, 1736, 1601, 1578,
1541, 1512, 1489, 1466, 1433, 1400, 1377, 1360, 1223, 1200,
1182, 1153, 1126, 1117, 1076, 1024, 993, 949, 905, 835, 808,
779, 752, 689 cm¹1; Anal. Calcd for C43H48O4SSi2: C, 72.02;
H, 6.75%. Found: C, 71.86; H, 6.86%.
Preparation of 2-{[2-(Acetoxymethyl)phenyl]dimethylsi-
lyl}-5-(4-{dimethyl[2-(tetrahydro-2H-pyranoxymethyl)phen-
yl]silyl}phenyl)thiophene (16¤a). To a mixture of 15a (2.9 g,
6.0 mmol), K2CO3 (2.1 g, 15.0 mmol), [(allyl)PdCl]2 (32 mg,
87 ¯mol), RuPhos (176 mg, 0.38 ¯mol), and CuI (103 mg,
0.54 ¯mol) in DMF (4.8 mL) and THF (13 mL) was added 5¤f
(2.7 g, 7.2 mmol), and the resulting mixture was stirred at 75 °C
for 8 h. The mixture was filtered through a Florisil pad, and the
filtrate was diluted with diethyl ether and washed with water
and then brine. The organic layer was dried over anhydrous
MgSO4 and concentrated in vacuo. The residue was purified by
flash chromatography on silica gel to give the corresponding
coupling product (3.2 g, 87%) as a pale yellow oil, Rf = 0.13
1
(hexane-ethyl acetate = 10:1). H NMR (400 MHz, CDCl3): ¤
7.63-7.24 (m, 13H), 7.20 (d, J = 3.3 Hz, 1H), 5.10 (s, 2H),
4.67 (d, J = 12.1 Hz, 1H), 4.45 (br s, 1H), 4.39 (d, J = 12.1 Hz,
1H), 3.82-3.69 (m, 1H), 3.45-3.37 (m, 1H), 2.00 (s, 3H), 1.85-
1.71 (m, 1H), 1.67-1.39 (m, 5H), 0.69 (s, 6H), 0.61 (s, 6H);
13C NMR (101 MHz, CDCl3): ¤ 170.4, 150.3, 144.0, 141.1,
138.2, 137.8, 136.6, 136.3, 135.8, 135.43, 135.35, 134.5,
134.4, 129.9, 129.56, 129.53, 128.5, 127.6, 126.7, 125.2,
124.4, 97.8, 68.8, 66.6, 62.0, 30.6, 25.5, 21.1, 19.4, 0.2, ¹0.8,
¹0.9; IR (neat): 3055, 3013, 2951, 2899, 2870, 2851, 1738,
1697, 1593, 1566, 1543, 1524, 1466, 1454, 1433, 1379, 1360,
1319, 1234, 1202, 1182, 1153, 1117, 1078, 1026, 995, 974,
949, 907, 870, 812, 777, 756, 729, 689, 660, 638, 615,
588 cm¹1; Anal. Calcd for C35H42O4SSi2: C, 68.36; H, 6.88%.
Found: C, 68.24; H, 6.99%.
Preparation of 2-{[2-(Acetoxymethyl)phenyl]dimethylsi-
lyl}-5-(4-{[2-(hydroxymethyl)phenyl]dimethylsilyl}phenyl)-
thiophene (16a). To a solution of 16¤a (3.2 g, 5.2 mmol) in
MeOH (50 mL) was added pyridinium p-toluenesulfonate
(PPTS, 0.30 g, 1.2 mmol), and the resulting mixture was stirred
at 40 °C for 3 h. After concentration in vacuo, the residue was
purified by flash chromatography on silica gel to give the title
compound (2.5 g, 92%) as a colorless viscous oil, Rf = 0.08
1
(hexane-ethyl acetate = 5:1). H NMR (400 MHz, CDCl3): ¤
7.63-7.54 (m, 4H), 7.51-7.28 (m, 9H), 7.21 (d, J = 3.7 Hz,
1H), 5.10 (s, 2H), 4.56 (d, J = 6.0 Hz, 2H), 2.00 (s, 3H), 1.33
(t, J = 5.9 Hz, 1H), 0.69 (s, 6H), 0.63 (s, 6H); 13C NMR (101
MHz, CDCl3): ¤ 170.4, 150.1, 146.4, 141.1, 138.1, 137.9,
136.5, 136.3, 135.40, 135.37, 134.7, 134.3, 129.91, 129.86,
129.5, 127.8, 127.6, 126.8, 125.3, 124.5, 109.6, 66.6, 65.2,
21.0, 0.2, ¹0.9; IR (neat): 3441, 3055, 3011, 2955, 2899, 1738,
1593, 1564, 1543, 1524, 1468, 1433, 1381, 1362, 1317, 1298,
1256, 1236, 1163, 1126, 1111, 1078, 1026, 995, 949, 924, 876,
812, 777, 756, 729, 691, 660, 638, 606, 588 cm¹1; Anal. Calcd
for C30H34O3SSi2: C, 67.88; H, 6.46%. Found: C, 67.74; H,
6.48%.
2-{[2-(Acetoxymethyl)phenyl]dimethylsilyl}-5-[4-(7-{di-
methyl[2-(tetrahydro-2H-pyranoxymethyl)phenyl]silyl}-9,9-
dioctyl-9H-fluoren-2-yl)phenyl]thiophene (17ac, Entry 2 of
Preparation of 5-(4-{[2-(Acetoxymethyl)phenyl]dimethyl-
silyl}phenyl)-2-{[2-(hydroxymethyl)phenyl]dimethylsilyl}-
thiophene (16b). To a mixture of 15b (0.50 g, 1.0 mmol),
Table 5);
A brown viscous oil, Rf = 0.10 (hexane-ethyl

J. Chen et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
565
1
acetate = 10:1). H NMR (400 MHz, CDCl3): ¤ 7.76 (d, J =
7.7 Hz, 1H), 7.72-7.54 (m, 6H), 7.52-7.34 (m, 9H), 7.28-7.22
(m, 4H), 5.13 (s, 2H), 4.70 (d, J = 11.9 Hz, 1H), 4.52 (t,
J = 3.5 Hz, 1H), 4.44 (d, J = 12.1 Hz, 1H), 3.87-3.77 (m, 1H),
3.49-3.41 (m, 1H), 2.04-1.90 (m, 7H), 1.88-1.77 (m, 1H),
1.72-1.43 (m, 5H), 1.29-0.98 (m, 20H), 0.82 (t, J = 7.0 Hz,
6H), 0.76-0.60 (m, 4H), 0.72 (s, 6H), 0.66 (s, 6H); 13C NMR
(101 MHz, CDCl3): ¤ 170.4, 151.5, 150.1, 150.0, 144.0, 141.4,
141.1, 140.6, 140.3, 139.3, 137.7, 137.2, 136.6, 136.4, 135.5,
135.4, 132.9, 132.6, 129.9, 129.5, 129.4, 128.4, 128.2, 127.6,
127.4, 126.6, 126.2, 125.6, 124.3, 121.1, 120.0, 119.1, 97.6,
68.8, 66.6, 61.9, 55.1, 40.3, 31.9, 30.6, 30.1, 29.29, 29.27,
25.6, 23.9, 22.7, 21.0, 19.4, 14.2, 0.2, ¹0.6, ¹0.7 (a signal for
sp2-carbon overlaps with others); IR (neat): 2920, 2849, 1736,
1531, 1477, 1431, 1377, 1346, 1277, 1250, 1232, 1157, 1128,
1117, 1097, 1078, 1024, 995, 974, 949, 905, 860, 835, 802,
¹1
775, 754, 689, 648, 582, 505 cm
; Anal. Calcd for
C49H53NO4SSi2: C, 72.82; H, 6.61%. Found: C, 72.60; H,
6.62%.
Cross-Coupling Reaction of 16b with 5b-5e. A General
Procedure: To a mixture of 16b (0.27 g, 0.50 mmol), K2CO3
(0.17 g, 1.25 mmol), PdCl2(dppf)¢CH2Cl2 (21 mg, 25 ¯mol),
and CuI (4.8 mg, 25 ¯mol) in DMF (0.4 mL) and THF (1.1 mL)
was added 5b-5e (0.60 mmol), and the resulting mixture was
stirred at 50 °C for 6-9 h before filtration through a Florisil pad.
The filtrate was diluted with diethyl ether and washed with
water and then brine. The organic layer was dried over
anhydrous MgSO4 and concentrated in vacuo. The residue was
purified by flash chromatography on silica gel to give 17bb-
17be in a yield listed in Entries 5-8 of Table 5.
1578, 1541, 1464, 1437, 1406, 1377, 1364, 1254, 1225, 1202,
¹1
1117, 1078, 1026, 955, 951, 907, 837, 806, 777, 754 cm
;
Anal. Calcd for C64H82O4SSi2: C, 76.60; H, 8.24%. Found: C,
76.80; H, 8.42%.
7-[4-(5-{[2-(Acetoxymethyl)phenyl]dimethylsilyl}thiophen-
2-yl)phenyl]-3-{dimethyl[2-(tetrahydro-2H-pyranoxymethyl)-
(E)-2-(4-{[2-(Acetoxymethyl)phenyl]dimethylsilyl}phenyl)-
5-[4-(2-{dimethyl[2-(tetrahydro-2H-pyranoxymethyl)phen-
yl]silyl}ethenyl)phenyl]thiophene (17bb, Entry 5 of
Table 5);
A yellow viscous oil, Rf = 0.25 (hexane-ethyl
1
phenyl]silyl}-5,5-dipentyl-5H-dibenzo[b,d]silole
(17ad,
acetate = 5:1). H NMR (400 MHz, CDCl3): ¤ 7.63-7.56 (m,
6H), 7.53-7.23 (m, 12H), 6.93 (d, J = 19.0 Hz, 1H), 6.68 (d,
J = 19.0 Hz, 1H), 5.01 (s, 2H), 4.87 (d, J = 11.9 Hz, 1H), 4.67
(t, J = 3.5 Hz, 1H), 4.62 (d, J = 11.9 Hz, 1H), 3.93-3.83 (m,
1H), 3.53-3.44 (m, 1H), 1.92 (s, 3H), 1.90-1.44 (m, 6H), 0.64
(s, 6H), 0.51 (s, 6H); 13C NMR (101 MHz, CDCl3): ¤ 170.4,
143.9, 143.8, 143.3, 141.1, 137.7, 137.3, 136.9, 136.5, 135.6,
134.9, 134.7, 134.5, 133.7, 129.7, 129.5, 129.4, 128.4, 128.0,
127.6, 126.9, 126.8, 125.5, 124.8, 124.2, 124.0, 97.9, 68.9,
66.6, 62.2, 30.7, 25.6, 21.0, 19.5, ¹0.9, ¹1.0, ¹1.1 (a signal
for sp2-carbon overlaps with others); IR (neat): 2916, 2849,
1738, 1595, 1578, 1539, 1493, 1470, 1454, 1435, 1412, 1391,
1377, 1360, 1248, 1225, 1200, 1113, 1076, 1024, 814, 793,
777, 754, 729, 665 cm¹1; HRMS (EI) Calcd for C43H48O4SSi2:
M+, 716.2812. Found: m/z 716.2806.
Entry 3 of Table 5); A yellow viscous oil, Rf = 0.30
1
(hexane-ethyl acetate = 5:1). H NMR (400 MHz, CDCl3): ¤
7.88 (d, J = 8.1 Hz, 1H), 7.83 (d, J = 1.6 Hz, 1H), 7.80 (d,
J = 7.5 Hz, 1H), 7.75 (s, 1H), 7.72-7.60 (m, 6H), 7.59-7.33
(m, 8H), 7.32-7.24 (m, 1H), 7.24 (d, J = 3.5 Hz, 1H), 5.13 (s,
2H), 4.71 (d, J = 11.9 Hz, 1H), 4.50 (t, J = 3.5 Hz, 1H), 4.45
(d, J = 11.9 Hz, 1H), 3.82-3.73 (m, 1H), 3.46-3.33 (m, 1H),
2.01 (s, 3H), 1.86-1.72 (m, 1H), 1.70-1.16 (m, 17H), 1.00-
0.92 (m, 4H), 0.85-0.77 (m, 6H), 0.71 (s, 6H), 0.65 (s, 3H),
0.64 (s, 3H); 13C NMR (101 MHz, CDCl3): ¤ 170.3, 150.0,
148.5, 147.4, 144.0, 141.1, 140.2, 139.0, 138.8, 138.7, 137.6,
137.2, 137.0, 136.5, 136.4, 136.2, 135.9, 135.4, 132.9, 131.3,
129.9, 129.5, 129.4, 128.5, 128.4, 127.6, 127.2, 126.6, 126.2,
124.3, 121.2, 120.1, 97.6, 68.8, 66.5, 61.9, 35.6, 30.6, 25.5,
23.7, 22.2, 21.0, 19.4, 14.1, 12.3, 0.2, ¹0.7, ¹0.8 (a signal for
sp2-carbon overlaps with others); IR (neat): 2953, 2916, 2849,
5-(4-{[2-(Acetoxymethyl)phenyl]dimethylsilyl}phenyl)-2-
(7-{dimethyl[2-(tetrahydro-2H-pyranoxymethyl)phenyl]si-
lyl}-9,9-dioctyl-9H-fluoren-2-yl)thiophene (17bc, Entry 6 of
1736, 1578, 1541, 1460, 1433, 1414, 1379, 1364, 1252, 1236,
¹1
1202, 1115, 1078, 1024, 997, 951, 837, 810, 777, 754 cm
;
Table 5);
A yellow viscous oil, Rf = 0.13 (hexane-ethyl
1
Anal. Calcd for C57H70O4SSi3: C, 73.18; H, 7.54%. Found: C,
73.27; H, 7.79%.
6-[4-(5-{[2-(Acetoxymethyl)phenyl]dimethylsilyl}thiophen-
2-yl)phenyl]-3-{dimethyl[2-(tetrahydro-2H-pyranoxymeth-
yl)phenyl]silyl}-9-ethyl-9H-carbazole (17ae, Entry 4 of
acetate = 10:1). H NMR (400 MHz, CDCl3): ¤ 7.70 (d, J =
7.9 Hz, 1H), 7.67 (d, J = 7.5 Hz, 1H), 7.65-7.58 (m, 4H), 7.57
(s, 1H), 7.53-7.32 (m, 12H), 7.29-7.22 (m, 1H), 5.02 (s, 2H),
4.70 (d, J = 12.1 Hz, 1H), 4.52 (t, J = 3.5 Hz, 1H), 4.43 (d,
J = 12.1 Hz, 1H), 3.87-3.76 (m, 1H), 3.50-3.40 (m, 1H), 2.03-
1.90 (m, 4H), 1.93 (s, 3H), 1.89-1.76 (m, 1H), 1.72-1.42 (m,
5H), 1.30-0.97 (m, 20H), 0.82 (t, J = 7.0 Hz, 6H), 0.73-0.59
(m, 4H), 0.66 (s, 6H), 0.65 (s, 6H); 13C NMR (101 MHz,
CDCl3): ¤ 170.4, 151.6, 149.9, 144.5, 144.0, 142.9, 141.3,
141.1, 140.5, 137.5, 137.4, 137.0, 136.6, 135.6, 135.5, 134.8,
134.5, 133.1, 132.6, 129.7, 129.5, 129.4, 128.4, 128.2, 127.6,
126.6, 124.8, 124.4, 124.1, 123.7, 120.1, 119.7, 119.0, 97.6,
68.8, 66.6, 61.9, 55.1, 40.3, 31.9, 30.6, 30.1, 29.31, 29.28,
25.6, 23.9, 22.7, 21.0, 19.4, 14.2, ¹0.6, ¹0.7, ¹0.9; IR (neat):
2920, 2849, 1740, 1595, 1578, 1541, 1466, 1437, 1377, 1360,
1246, 1225, 1202, 1115, 1078, 1026, 976, 907, 814, 800, 775,
754, 729, 689 cm¹1; Anal. Calcd for C64H82O4SSi2: C, 76.60;
H, 8.24%. Found: C, 76.59; H, 8.29%.
Table 5);
A yellow viscous oil, Rf = 0.15 (hexane-ethyl
8.32 (d,
acetate = 5:1). 1H NMR (400 MHz, CDCl3):
¤
J = 1.3 Hz, 1H), 8.31 (s, 1H), 7.75-7.56 (m, 8H), 7.52-7.36
(m, 8H), 7.30 (td, J = 7.3, 1.3 Hz, 1H), 7.24 (d, J = 3.3 Hz,
1H), 5.14 (s, 2H), 4.71 (d, J = 12.1 Hz, 1H), 4.45 (d, J =
11.9 Hz, 1H), 4.45-4.35 (m, 3H), 3.76-3.67 (m, 1H), 3.37-3.28
(m, 1H), 2.02 (s, 3H), 1.82-1.69 (m, 1H), 1.63-1.37 (m, 5H),
1.47 (t, J = 7.2 Hz, 3H), 0.72 (s, 6H), 0.713 (s, 3H), 0.710 (s,
3H); 13C NMR (101 MHz, CDCl3): ¤ 170.4, 150.3, 144.1,
141.14, 141.09, 141.0, 139.3, 137.3, 136.8, 136.7, 136.4,
135.4, 132.1, 131.5, 131.4, 129.9, 129.5, 129.4, 128.5, 127.6,
127.4, 126.6, 126.4, 126.2, 124.8, 124.1, 123.3, 122.8, 118.6,
108.6, 108.3, 97.8, 68.9, 66.6, 62.0, 37.7, 30.6, 25.5, 21.1,
19.4, 14.0, 0.3, ¹0.3, ¹0.4 (two sp2-carbon signals overlap
with others); IR (neat): 3049, 2949, 1736, 1624, 1591, 1564,
7-[5-(4-{[2-(Acetoxymethyl)phenyl]dimethylsilyl}phenyl)-
thiophen-2-yl]-3-{dimethyl[2-(tetrahydro-2H-pyranoxymeth-

566
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
Synthesis of Biaryls and Oligoarenes
yl)phenyl]silyl}-5,5-dipentyl-5H-dibenzo[b,d]silole
(17bd,
1111, 1099, 1080, 1011, 986, 949, 854, 837, 824, 779, 754,
733, 675, 648 cm¹1; Anal. Calcd for C15H16Br2OSi: C, 45.02;
H, 4.03%. Found: C, 44.99; H, 3.93%.
Entry 7 of Table 5); A yellow viscous oil, Rf = 0.33
1
(hexane-ethyl acetate = 5:1). H NMR (400 MHz, CDCl3): ¤
7.86-7.73 (m, 2H), 7.69 (d, J = 8.6 Hz, 1H), 7.64-7.58 (m,
3H), 7.58-7.24 (m, 14H), 5.02 (s, 2H), 4.71 (d, J = 11.9 Hz,
1H), 4.50 (t, J = 6.2 Hz, 1H), 4.44 (d, J = 11.7 Hz, 1H), 3.83-
3.73 (m, 1H), 3.46-3.37 (m, 1H), 1.93 (s, 3H), 1.85-1.73 (m,
1H), 1.68-1.17 (m, 17H), 0.96 (distorted t, J = 8.1 Hz, 4H),
0.82 (t, J = 6.6 Hz, 6H), 0.65 (s, 12H); 13C NMR (101 MHz,
CDCl3): ¤ 170.4, 148.4, 147.6, 144.0, 143.0, 141.2, 139.0,
138.8, 137.5, 137.4, 137.0, 136.3, 136.0, 135.6, 135.5, 134.8,
134.5, 132.9, 130.1, 129.8, 129.5, 129.4, 128.4, 127.6, 127.3,
126.7, 124.8, 124.2, 123.7, 121.2, 120.1, 97.7, 68.8, 66.6, 62.0,
35.6, 30.6, 25.6, 23.7, 22.2, 21.0, 19.4, 14.1, 12.4, ¹0.7, ¹0.8,
¹0.9 (two signals for sp2-carbons overlap with others); IR
(neat): 2953, 2918, 2849, 1738, 1593, 1578, 1539, 1466, 1439,
1392, 1377, 1366, 1250, 1225, 1200, 1113, 1076, 1026, 976,
953, 907, 824, 800, 775, 754, 729, 665 cm¹1; Anal. Calcd for
C57H70O4SSi3: C, 73.18; H, 7.54%. Found: C, 72.88; H, 7.61%.
6-[5-(4-{[2-(Acetoxymethyl)phenyl]dimethylsilyl}phenyl)-
thiophen-2-yl]-3-{dimethyl[2-(tetrahydro-2H-pyranoxymeth-
yl)phenyl]silyl}-9-ethyl-9H-carbazole (17be, Entry 8 of
Preparation of (3,5-Dibromophenyl)dimethyl[2-(tetra-
hydro-2H-pyranoxymethyl)phenyl]silane (18¤). A solution
of 18 (3.9 g, 9.8 mmol) and 3,4-dihydro-2H-pyran (1.81 g,
14.7 mmol) and PPTS (0.25 g, 0.98 mmol) in CH2Cl2 (69 mL)
was stirred at rt for 5 h. The mixture was diluted with diethyl
ether (50 mL) and then neutralized with a saturated aqueous
NaHCO3 solution. The organic layer was dried over anhydrous
MgSO4 and concentrated in vacuo. Purification of the residue
by flash chromatography on silica gel gave the title compound
(3.8 g, 81%) as a pale brown oil, Rf = 0.38 (hexane-ethyl
1
acetate = 10:1). H NMR (400 MHz, CDCl3): ¤ 7.64 (t, J =
1.8 Hz, 1H), 7.54-7.40 (m, 5H), 7.32 (t, J = 7.3 Hz, 1H), 4.65
(d, J = 11.9 Hz, 1H), 4.48 (t, J = 6.8 Hz, 1H), 4.33 (d, J =
11.9 Hz, 1H), 3.83-3.72 (m, 1H), 3.51-3.41 (m, 1H), 1.86-1.73
(m, 1H), 1.69-1.43 (m, 5H), 0.61 (s, 3H), 0.60 (s, 3H);
13C NMR (101 MHz, CDCl3): ¤ 144.7, 143.9, 135.4, 134.9,
134.3, 134.2, 130.0, 128.9, 127.0, 123.1, 97.8, 68.8, 62.2, 30.5,
25.5, 19.5, ¹0.9, ¹1.0; IR (neat): 3055, 2941, 2870, 2849,
1562, 1537, 1439, 1381, 1352, 1258, 1202, 1128, 1099, 1078,
1055, 1026, 974, 907, 839, 822, 779, 756, 733, 689, 675,
648 cm¹1; Anal. Calcd for C20H24Br2O2Si: C, 49.60; H, 4.99%.
Found: C, 49.87; H, 4.99%.
Preparation of 1-Bromo-3-{dimethyl[2-(tetrahydro-2H-
pyranoxymethyl)phenyl]silyl}-5-{[2-(hydroxymethyl)phen-
yl]dimethylsilyl}benzene (19). To a solution of 18¤ (2.6 g,
5.3 mmol) and 2 (0.87 g, 5.3 mmol) in diethyl ether (10.6 mL)
was added a 1.58 M solution of t-BuLi in pentane (3.3 mL,
5.3 mmol) over 1 h at ¹78 °C, and the resulting mixture was
allowed to warm to rt overnight with stirring before being
quenched with water at 0 °C. The aqueous layer was extracted
with diethyl ether three times, and the combined organic layers
were dried over anhydrous MgSO4 and concentrated in vacuo.
The residue was purified by flash chromatography on silica gel
to give the title compound (2.8 g, 92%) as a colorless viscous
oil, Rf = 0.18 (hexane-ethyl acetate = 5:1). 1H NMR (400
MHz, CDCl3): ¤ 7.58-7.38 (m, 9H), 7.32-7.25 (m, 2H),
4.482 (d, J = 5.7 Hz, 2H), 4.480 (d, J = 12.1 Hz, 1H), 4.36 (t,
J = 3.4 Hz, 1H), 4.21 (d, J = 12.3 Hz, 1H), 3.72-3.62 (m, 1H),
3.40-3.37 (m, 1H), 2.49 (t, J = 5.6 Hz, 1H), 1.83-1.70 (m, 1H),
1.65-1.40 (m, 5H), 0.57 (s, 6H), 0.549 (s, 3H), 0.546 (s, 3H);
13C NMR (101 MHz, CDCl3): ¤ 146.8, 143.7, 141.7, 141.6,
137.4, 136.9, 136.8, 135.09, 135.06, 134.9, 134.0, 129.9,
129.8, 128.2, 126.81, 126.78, 126.6, 123.4, 97.7, 68.6, 64.8,
62.0, 30.5, 25.4, 19.3, ¹1.07, ¹1.09, ¹1.18, ¹1.21; IR (neat):
3439, 3055, 3011, 2949, 2895, 2872, 1589, 1564, 1537, 1464,
1454, 1435, 1410, 1385, 1377, 1356, 1323, 1285, 1258, 1200,
1182, 1134, 1078, 1055, 1024, 976, 907, 866, 824, 777, 748,
691, 648, 604 cm¹1; Anal. Calcd for C29H37BrO3Si2: C, 61.14;
H, 6.55%. Found: C, 61.33; H, 6.56%.
Table 5);
A yellow viscous oil, Rf = 0.18 (hexane-ethyl
acetate = 4:1). 1H NMR (400 MHz, CDCl3): ¤ 8.32 (s, 1H),
8.30 (s, 1H), 7.74 (dd, J = 8.4, 1.1 Hz, 1H), 7.64-7.22 (m,
17H), 5.02 (s, 2H), 4.70 (d, J = 11.9 Hz, 1H), 4.44 (d, J =
11.9 Hz, 1H), 4.44-4.32 (m, 3H), 3.76-3.67 (m, 1H), 3.36-3.28
(m, 1H), 1.93 (s, 3H), 1.81-1.68 (m, 1H), 1.65-1.30 (m, 8H),
0.71 (s, 6H), 0.65 (s, 6H); 13C NMR (101 MHz, CDCl3): ¤
170.4, 145.1, 144.0, 141.8, 141.1, 140.9, 139.3, 137.1, 137.0,
136.8, 135.6, 135.4, 135.0, 134.4, 131.5, 129.7, 129.5, 129.4,
128.5, 127.54, 127.48, 126.7, 126.4, 125.5, 124.6, 124.1,
123.8, 123.1, 122.7, 122.6, 117.5, 108.6, 108.3, 97.8, 68.8,
66.6, 61.9, 37.7, 30.5, 25.5, 21.0, 19.4, 14.0, ¹0.3, ¹0.4, ¹0.9;
IR (neat): 3456, 3055, 3013, 2955, 2930, 2897, 2856, 1738,
1589, 1472, 1435, 1427, 1402, 1379, 1362, 1252, 1225, 1204,
1126, 1111, 1082, 1063, 1026, 1011, 978, 876, 833, 814, 802,
¹1
775, 752, 700, 648 cm
; HRMS (FAB+) Calcd for
C49H53NO4SSi2: M+, 807.3234. Found: m/z 807.3231.
Preparation of (3,5-Dibromophenyl)[2-(hydroxymethyl)-
phenyl]dimethylsilane (18). To a solution of 1,3,5-tribromo-
benzene (4.7 g, 15 mmol) in diethyl ether (150 mL) was added a
1.6 M solution of n-BuLi in hexane (9.4 mL, 15 mmol) over
30 min at ¹78 °C, and the resulting mixture was stirred at
¹78 °C for 2 h. To this was added 2 (2.5 g, 15 mmol) at ¹78 °C,
and the resulting mixture was allowed to warm to rt overnight
with stirring before being quenched with water at 0 °C. The
aqueous layer was extracted with diethyl ether three times, and
the combined organic layers were dried over anhydrous MgSO4
and concentrated in vacuo. The residue was purified by flash
chromatography on silica gel to give the title compound (5.9 g,
98%) as a pale brown oil, Rf = 0.22 (hexane-ethyl acetate =
1
5:1). H NMR (400 MHz, CDCl3): ¤ 7.66 (t, J = 1.8 Hz, 1H),
Preparation of 1-Bromo-3-({2-[(tert-butyldiphenylsilyl-
oxy)methyl]phenyl}dimethylsilyl)-5-{dimethyl[2-(tetrahydro-
2H-pyranoxymethyl)phenyl]silyl}benzene (19¤). A solution
of 19 (2.8 g, 4.9 mmol) and tert-butyldiphenylsilyl chloride
(1.48 g, 5.4 mmol) and imidazole (0.73 g, 10.8 mmol) in DMF
(4.9 mL) was stirred at rt for 3 h. The mixture was diluted with
diethyl ether, and water was added. The organic layer was dried
7.53 (d, J = 7.3 Hz, 1H), 7.50-7.42 (m, 4H), 7.36-7.30 (m,
1H), 4.56 (d, J = 5.9 Hz, 2H), 1.42 (t, J = 5.9 Hz, 1H), 0.62 (s,
6H); 13C NMR (101 MHz, CDCl3): ¤ 146.3, 144.7, 135.6,
134.8, 134.4, 133.9, 130.3, 127.8, 127.1, 123.3, 65.4, ¹0.9; IR
(neat): 3576, 3342, 3055, 2955, 2918, 2895, 1591, 1562, 1537,
1464, 1435, 1421, 1410, 1381, 1356, 1288, 1252, 1202, 1126,

J. Chen et al.
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
567
over anhydrous MgSO4 and then concentrated in vacuo. The
residue was purified by flash chromatography on silica gel to
give the title compound (3.8 g, 96%) as a colorless viscous oil,
then concentrated in vacuo. The residue was purified by flash
chromatography on silica gel to give the title compound (8.8 g,
98%) as a pale yellow oil, Rf = 0.38 (hexane-ethyl acetate =
30:1). 1H NMR (400 MHz, CDCl3): ¤ 7.74 (dd, J = 8.1, 0.9 Hz,
1H), 7.62-7.56 (m, 4H), 7.50-7.32 (m, 8H), 7.27 (t, J = 7.3 Hz,
1H), 6.90 (d, J = 3.5 Hz, 1H), 6.72 (d, J = 3.5 Hz, 1H), 4.68 (s,
2H), 1.09 (s, 9H), 0.43 (s, 6H); 13C NMR (101 MHz, CDCl3): ¤
146.8, 141.0, 135.4, 134.5, 133.2, 132.5, 131.0, 130.1, 129.6,
127.6, 126.1, 125.8, 117.2, 65.5, 27.0, 19.4, ¹0.3 (a signal for
sp2-carbon overlaps with others); IR (neat): 3069, 3051, 3013,
2957, 2930, 2893, 2856, 1958, 1888, 1821, 1589, 1541, 1504,
1
Rf = 0.32 (hexane-ethyl acetate = 10:1). H NMR (400 MHz,
CDCl3): ¤ 7.68 (d, J = 7.1 Hz, 1H), 7.61-7.55 (m, 4H), 7.51
(dd, J = 2.1, 1.0 Hz, 1H), 7.47-7.29 (m, 13H), 7.27-7.19 (m,
2H), 4.61 (s, 2H), 4.60 (d, J = 11.9 Hz, 1H), 4.45 (t, J = 5.9
Hz, 1H), 4.31 (d, J = 11.9 Hz, 1H), 3.81-3.72 (m, 1H), 3.46-
3.38 (m, 1H), 1.85-1.71 (m, 1H), 1.67-1.40 (m, 5H), 1.06 (s,
9H), 0.50 (s, 3H), 0.49 (s, 3H), 0.36 (s, 6H); 13C NMR
(101 MHz, CDCl3): ¤ 146.6, 143.8, 141.5, 141.1, 137.4, 137.1,
136.7, 135.31, 135.26, 134.9, 133.2, 132.9, 129.8, 129.6,
129.5, 128.7, 127.6, 126.8, 126.1, 125.9, 123.3, 97.6, 68.7,
65.7, 62.0, 30.6, 27.0, 25.5, 19.4, ¹0.9, ¹1.0, ¹1.2 (two
signals for sp2- and sp3-carbons overlap with others); IR (neat):
3057, 2951, 2918, 2851, 1580, 1560, 1541, 1466, 1427, 1356,
1256, 1202, 1128, 1113, 1080, 1063, 1026, 974, 907, 837, 822,
777, 743, 700 cm¹1; Anal. Calcd for C45H55BrO3Si3: C, 66.88;
H, 6.86%. Found: C, 66.72; H, 6.79%.
1472, 1427, 1404, 1391, 1362, 1286, 1258, 1204, 1124, 1111,
¹1
1063, 999, 955, 831, 816, 777, 743, 702, 656, 617, 592 cm
.
Anal. Calcd for C29H33BrOSSi2: C, 61.57; H, 5.88%. Found: C,
61.87; H, 5.96%.
Preparation of 4¤-{[2-(Acetoxymethyl)phenyl]dimethyl-
silyl}-3-({2-[(tert-butyldiphenylsilyloxy)methyl]phenyl}di-
methylsilyl)-5-{dimethyl[2-(tetrahydro-2H-pyranoxymeth-
yl)phenyl]silyl}biphenyl (21¤). To a mixture of 20 (0.22 g,
0.25 mmol), K2CO3 (86 mg, 0.63 mmol), [(allyl)PdCl]2 (2.2 mg,
6.0 ¯mol), RuPhos (12.3 mg, 27 ¯mol), and CuI (2.4 mg, 13
¯mol) in DMF (0.2 mL) and THF (0.55 mL) was added 5¤a
(109 mg, 0.30 mmol), and the resulting mixture was stirred at
50 °C for 27 h. The mixture was filtered through a Florisil
pad, and the filtrate was diluted with diethyl ether and washed
with water and then brine. The organic layer was dried over
anhydrous MgSO4 and concentrated in vacuo. The residue was
purified by flash chromatography on silica gel to give the title
compound (0.18 g, 70%) as a colorless viscous oil, Rf = 0.30
Preparation of 1-({2-[(tert-Butyldiphenylsilyloxy)methyl]-
phenyl}dimethylsilyl)-3-{dimethyl[2-(tetrahydro-2H-pyran-
oxymethyl)phenyl]silyl}-5-{[2-(hydroxymethyl)phenyl]di-
methylsilyl}benzene (20).
To a solution of 19¤ (0.58 g,
0.70 mmol) and 2 (117 mg, 0.70 mmol) in diethyl ether (14 mL)
was added a 1.58 M solution of t-BuLi in pentane (0.45 mL,
0.70 mmol) over 1 h at ¹78 °C, and the resulting mixture was
allowed to warm to rt overnight with stirring before being
quenched with water at 0 °C. The aqueous layer was extracted
with diethyl ether three times, and the combined organic layers
were dried over anhydrous MgSO4 and concentrated in vacuo.
The residue was purified by flash chromatography on silica gel
to give the title compound (0.52 g, 81%) as a colorless viscous
oil, Rf = 0.22 (hexane-ethyl acetate = 5:1). 1H NMR (400
MHz, CDCl3): ¤ 7.65 (d, J = 7.3 Hz, 1H), 7.62-7.57 (m,
4H), 7.55 (t, J = 1.3 Hz, 1H), 7.51-7.14 (m, 19H), 4.67 (s, 2H),
4.47 (d, J = 12.3 Hz, 1H), 4.42 (d, J = 5.7 Hz, 2H), 4.37 (t,
J = 3.3 Hz, 1H), 4.21 (d, J = 12.1 Hz, 1H), 3.74-3.65 (m, 1H),
3.39-3.31 (m, 1H), 2.14 (t, J = 5.6 Hz, 1H), 1.82-1.69 (m, 1H),
1.65-1.38 (m, 5H), 1.06 (s, 9H), 0.48 (s, 12H), 0.321 (s, 3H),
0.319 (s, 3H); 13C NMR (101 MHz, CDCl3): ¤ 146.8, 146.5,
143.7, 140.2, 140.1, 136.9, 136.8, 136.6, 135.8, 135.4, 135.14,
135.09, 135.0, 134.9, 133.9, 133.3, 129.6, 129.5, 129.4, 128.1,
127.5, 126.8, 126.6, 126.4, 126.0, 125.8, 97.6, 68.7, 65.8, 64.8,
61.8, 30.5, 27.0, 25.5, 19.5, 19.2, ¹0.9, ¹1.1 (a signal for sp2-
carbon overlaps with others); IR (neat): 3441, 3053, 3003,
2953, 2856, 1589, 1560, 1541, 1466, 1427, 1375, 1249, 1202,
1124, 1113, 1080, 1061, 1026, 841, 826, 775, 750, 702, 689,
644 cm¹1; Anal. Calcd for C54H68O4Si4: C, 72.59; H, 7.67%.
Found: C, 72.66; H, 7.65%.
1
(hexane-ethyl acetate = 5:1). H NMR (400 MHz, CDCl3): ¤
7.69 (d, J = 7.9 Hz, 1H), 7.63-7.18 (m, 28H), 5.02 (s, 2H),
4.69 (s, 2H), 4.65 (d, J = 12.1 Hz, 1H), 4.45 (t, J = 3.5 Hz,
1H), 4.38 (d, J = 12.1 Hz, 1H), 3.79-3.69 (m, 1H), 3.43-3.33
(m, 1H), 1.89 (s, 3H), 1.82-1.68 (m, 1H), 1.64-1.36 (m, 5H),
1.03 (s, 9H), 0.63 (s, 6H), 0.553 (s, 3H), 0.549 (s, 3H), 0.40 (s,
6H); 13C NMR (101 MHz, CDCl3): ¤ 170.3, 146.6, 143.9,
142.2, 141.2, 139.3, 138.4, 138.1, 137.0, 136.7, 135.9, 135.6,
135.4, 135.3, 134.9, 134.2, 133.6, 133.5, 133.2, 129.7, 129.5,
129.4, 128.5, 127.5, 126.7, 126.0, 125.7, 97.6, 68.8, 66.6,
65.8, 61.9, 30.5, 27.0, 25.5, 20.9, 19.4, ¹0.7, ¹0.8, ¹1.1 (five
signals for sp2-carbons and a signal for sp3-carbon overlap
with others); IR (neat): 3055, 3013, 2955, 2928, 2855, 1738,
1587, 1576, 1541, 1470, 1437, 1427, 1379, 1360, 1252, 1236,
¹1
1202, 1124, 1113, 1080, 1059, 1026, 841, 773, 754, 702 cm
;
HRMS (MALDI) Calcd for C62H74NaO5Si4: [M + Na]+,
1033.4511. Found: m/z 1033.4506.
Preparation of 4¤-{[2-(Acetoxymethyl)phenyl]dimethyl-
silyl}-3-{dimethyl[2-(tetrahydro-2H-pyranoxymethyl)phen-
yl]silyl}-5-{[(2-hydroxymethyl)phenyl]dimethylsilyl}biphen-
yl (21). 21¤ (2.7 g, 2.7 mmol) was treated with a 1.0 M solution
of TBAF in THF (5.4 mL, 5.4 mmol) at rt for 1 h. The mixture
was filtered through a Florisil pad, and the filtrate was diluted
with diethyl ether and washed with water and then brine. The
organic layer was dried over anhydrous MgSO4 and concen-
trated in vacuo. The residue was purified by flash chromatog-
raphy on silica gel to give the title compound (1.6 g, 77%) as a
colorless viscous oil, Rf = 0.20 (hexane-ethyl acetate = 4:1).
1H NMR (400 MHz, CDCl3): ¤ 7.66 (dd, J = 1.9, 1.2 Hz, 1H),
7.63-7.24 (m, 18H), 5.00 (s, 2H), 4.53 (d, J = 5.3 Hz, 2H),
Preparation of (5-Bromothiophen-2-yl){2-[(tert-butyldi-
phenylsilyloxy)methyl]phenyl}dimethylsilane (5¤¤f).
A
solution of 5-bromothienyl[2-(hydroxymethyl)phenyl]dimeth-
ylsilane (5.2 g, 15.9 mmol, prepared by C(5)-silylation of 2-
bromothiophene through C(5)-lithiation with LDA, transmeta-
lation with MgBr2¢Et2O, and silylation with 2 in 64% yield),
t-butyldiphenylsilyl chloride (4.9 g, 17.6 mmol) and imidazole
(2.4 g, 35 mmol) in DMF (16 mL) was stirred at rt for 3 h.
The mixture was diluted with diethyl ether, and water was
added. The organic layer was dried over anhydrous MgSO4 and

568
Bull. Chem. Soc. Jpn. Vol. 83, No. 5 (2010)
Synthesis of Biaryls and Oligoarenes
4.52 (d, J = 12.4 Hz, 1H), 4.36 (t, J = 3.4 Hz, 1H), 4.26 (d,
J = 12.3 Hz, 1H), 3.70-3.60 (m, 1H), 3.36-3.27 (m, 1H), 2.49
(t, J = 5.6 Hz, 1H), 1.89 (s, 3H), 1.80-1.67 (m, 1H), 1.62-1.36
(m, 5H), 0.62 (s, 6H), 0.61 (s, 6H), 0.592 (s, 3H), 0.587 (s, 3H);
13C NMR (101 MHz, CDCl3): ¤ 170.4, 146.9, 143.7, 142.0,
141.1, 139.5, 138.6, 138.3, 137.0, 136.9, 135.6, 135.1, 135.0,
134.7, 134.2, 133.4, 133.3, 129.7, 129.54, 129.50, 128.1,
127.5, 126.74, 126.69, 126.65, 126.5, 97.7, 68.7, 66.6, 64.8,
61.8, 30.4, 25.4, 20.9, 19.2, ¹0.87, ¹0.92, ¹1.0, ¹1.05, ¹1.09
(three signals for sp2-carbons overlap with others); IR (neat):
3441, 3055, 3013, 2953, 2920, 2868, 2851, 1736, 1597, 1591,
1578, 1541, 1464, 1437, 1408, 1379, 1362, 1250, 1202, 1126,
1115, 1078, 1057, 1024, 974, 841, 800, 773, 754, 687, 665,
5.01 (s, 2H), 4.72 (s, 2H), 4.62 (d, J = 6.0 Hz, 2H), 1.92 (s,
3H), 1.42 (t, J = 6.0 Hz, 1H), 1.06 (s, 9H), 0.68 (s, 6H), 0.65
(s, 6H), 0.47 (s, 6H); 13C NMR (101 MHz, CDCl3): ¤ 170.4,
149.7, 146.8, 146.4, 141.4, 141.1, 140.9, 140.3, 138.0, 137.4,
137.0, 136.1, 135.6, 135.5, 135.3, 135.1, 134.5, 134.3, 134.2,
133.2, 133.1, 131.7, 130.2, 129.93, 129.89, 129.7, 129.5,
129.4, 127.8, 127.6, 127.5, 126.9, 126.6, 126.1, 125.8, 125.6,
124.6, 66.6, 65.5, 65.3, 27.0, 21.0, 19.4, ¹0.2, ¹0.8, ¹0.9; IR
(neat): 3456, 3055, 3013, 2957, 2930, 2895, 2856, 1738, 1589,
1472, 1437, 1427, 1402, 1379, 1362, 1256, 1225, 1126, 1111,
1082, 1063, 1028, 1011, 978, 876, 833, 814, 777, 754, 702,
665, 650, 617, 592 cm¹1; Anal. Calcd for C61H68O4SSi4: C,
72.57; H, 6.79%. Found: C, 72.33; H, 6.57%.
¹
646 cm¹1; HRMS (FAB¹) Calcd for C46H55O5Si3: [M ¹ H] ,
Preparation of 5-[4¤-{[2-(Acetoxymethyl)phenyl]dimeth-
ylsilyl}-5-(7-{dimethyl[2-(tetrahydro-2H-pyranoxymethyl)-
phenyl]silyl}-9,9-dioctyl-9H-fluoren-2-yl)biphenyl-3-yl]-2-
({2-[(tert-butyldiphenylsilyloxy)methyl]phenyl}dimethylsilyl)-
771.3357. Found: m/z 771.3361.
Preparation of 5-(4¤-{[2-(Acetoxymethyl)phenyl]dimeth-
ylsilyl}-5-{dimethyl[2-(tetrahydro-2H-pyranoxymethyl)phen-
yl]silyl}biphenyl-3-yl)-2-({2-[(tert-butyldiphenylsilyloxy)-
methyl]phenyl}dimethylsilyl)thiophene (22¤). To a mixture
of 21 (1.16 g, 1.50 mmol), K2CO3 (0.52 g, 3.8 mmol), [(allyl)-
PdCl]2 (13.2 mg, 36 ¯mol), RuPhos (74 mg, 0.160 ¯mol), and
CuI (14.4 mg, 76 ¯mol) in DMF (1.2 mL) and THF (3.3 mL)
was added 5¤¤f (1.02 g, 1.8 mmol), and the resulting mixture
was stirred at 50 °C for 19 h. The mixture was filtered through a
Florisil pad, and the filtrate was diluted with diethyl ether and
washed with water and then brine. The organic layer was dried
over anhydrous MgSO4 and concentrated in vacuo. The residue
was purified by flash chromatography on silica gel to give
the title compound (1.46 g, 89%) as a colorless viscous oil,
Rf = 0.30 (hexane-ethyl acetate = 5:1). 1H NMR (400 MHz,
CDCl3): ¤ 7.74 (d, J = 7.7 Hz, 1H), 7.70 (t, J = 1.7 Hz, 1H),
7.65 (t, J = 1.3 Hz, 1H), 7.62-7.23 (m, 26H), 7.17 (d, J =
3.5 Hz, 1H), 6.94 (d, J = 3.5 Hz, 1H), 5.03 (s, 2H), 4.732 (s,
2H), 4.728 (d, J = 11.9 Hz, 1H), 4.49 (d, J = 11.9 Hz, 1H), 4.47
(t, J = 3.8 Hz, 1H), 3.78-3.68 (m, 1H), 3.40-3.32 (m, 1H), 1.93
(s, 3H), 1.80-1.67 (m, 1H), 1.64-1.32 (m, 5H), 1.07 (s, 9H),
0.672 (s, 3H), 0.668 (s, 3H), 0.65 (s, 6H), 0.47 (s, 6H); 13C NMR
(101 MHz, CDCl3): ¤ 170.3, 149.9, 146.8, 144.0, 141.6, 141.2,
140.8, 140.2, 137.8, 137.3, 137.0, 136.1, 135.6, 135.4, 135.3,
134.5, 134.3, 134.1, 133.2, 133.1, 131.9, 130.4, 129.8, 129.7,
129.6, 129.5, 129.4, 128.6, 127.53, 127.47, 126.8, 126.6, 126.1,
125.6, 124.5, 97.8, 68.9, 66.6, 65.5, 62.0, 30.6, 27.0, 25.5, 20.9,
19.5, 19.4, ¹0.2, ¹0.7, ¹0.80, ¹0.84 (two signals for sp2-
carbons overlap with others); IR (neat): 3049, 2955, 2918, 2851,
1736, 1578, 1560, 1541, 1466, 1435, 1427, 1377, 1364, 1250,
1225, 1202, 1126, 1113, 1080, 1061, 1026, 976, 831, 814, 775,
754, 700, 665 cm¹1; HRMS (FAB+) Calcd for C66H76O5SSi4:
M+, 1092.4491. Found: m/z 1092.4523.
thiophene (23).
To a mixture of 22 (0.50 g, 0.50 mmol),
K2CO3 (0.17 g, 1.25 mmol), [(allyl)PdCl]2 (9.1 mg, 25 ¯mol),
RuPhos (23 mg, 50 ¯mol), and CuI (4.8 mg, 25 ¯mol) in DMF
(0.8 mL) and THF (2.2 mL) was added 5c (0.43 g, 0.60 mmol),
and the resulting mixture was stirred at 50 °C for 24 h. The
mixture was filtered through a Florisil pad, and the filtrate was
diluted with diethyl ether and washed with water and then
brine. The organic layer was dried over anhydrous MgSO4 and
concentrated in vacuo. The residue was purified by flash
chromatography on silica gel to give the title compound
(0.54 g, 73%) as a colorless viscous oil, Rf = 0.28 (hexane-
ethyl acetate = 10:1). 1H NMR (400 MHz, CDCl3): ¤ 7.83-
7.21 (m, 36H), 7.01 (d, J = 3.3 Hz, 1H), 5.06 (s, 2H), 4.76 (s,
2H), 4.71 (d, J = 12.1 Hz, 1H), 4.53 (t, J = 3.0 Hz, 1H), 4.45
(d, J = 11.9 Hz, 1H), 3.87-3.77 (m, 1H), 3.51-3.42 (m, 1H),
2.08-1.90 (m, 4H), 1.96 (s, 3H), 1.90-1.77 (m, 1H), 1.72-1.43
(m, 5H), 1.37-0.86 (m, 20H), 1.08 (s, 9H), 0.80 (t, J = 7.0 Hz,
6H), 0.76-0.56 (m, 4H), 0.68 (s, 6H), 0.67 (s, 6H), 0.51 (s, 6H);
13C NMR (101 MHz, CDCl3): ¤ 170.4, 151.6, 150.0, 149.8,
146.8, 144.0, 142.7, 142.0, 141.5, 141.4, 141.2, 140.5, 139.7,
138.1, 137.6, 137.3, 136.9, 136.6, 136.1, 135.7, 135.5, 135.4,
135.2, 134.5, 134.4, 133.2, 133.1, 132.6, 129.9, 129.8, 129.50,
129.45, 129.4, 128.4, 128.2, 127.6, 127.5, 126.7, 126.6, 126.1,
126.0, 125.6, 125.2, 124.7, 124.0, 123.7, 121.4, 120.1, 119.2,
97.6, 68.8, 66.7, 65.5, 61.9, 55.2, 40.3, 31.9, 30.6, 30.1, 29.3,
27.0, 25.6, 24.0, 22.7, 21.0, 19.44, 19.41, 14.2, ¹0.21, ¹0.60,
¹0.69, ¹0.80 (a signal for sp3-carbon overlaps with others); IR
(neat): 3053, 3013, 2934, 2857, 1960, 1923, 1890, 1819, 1746,
1738, 1732, 1591, 1566, 1545, 1485, 1470, 1464, 1454, 1435,
1427, 1402, 1379, 1360, 1323, 1250, 1223, 1202, 1184, 1155,
1127, 1113, 1092, 1080, 1063, 1026, 1009, 978, 907, 876, 818,
777, 754, 702, 665, 657, 648, 623, 617, 592, 571, 554,
540 cm¹1; Anal. Calcd for C95H116O5SSi4: C, 76.97; H, 7.89%.
Found: C, 76.68; H, 7.89%.
Preparation of 5-(4¤-{[2-(Acetoxymethyl)phenyl]dimeth-
ylsilyl}-5-{[2-(hydroxymethyl)phenyl]dimethylsilyl}biphen-
yl-3-yl)-2-({2-[(tert-butyldiphenylsilyloxy)methyl]phenyl}di-
methylsilyl)thiophene (22).
A solution of 22¤ (1.46 g,
1.33 mmol) and PPTS (67 mg, 0.27 mmol) in MeOH (13 mL)
and THF (6.7 mL) was stirred at rt overnight before concen-
tration in vacuo. The residue was purified by flash chromatog-
raphy on silica gel to give the title compound (1.1 g, 80%) as a
colorless viscous oil, Rf = 0.18 (hexane-ethyl acetate = 4:1).
1H NMR (400 MHz, CDCl3): ¤ 7.76-7.69 (m, 2H), 7.66-7.22
(m, 27H), 7.17 (d, J = 3.5 Hz, 1H), 6.94 (d, J = 3.5 Hz, 1H),
This work has been supported financially by Grant-in-Aids
for Creative Scientific Research, Scientific Research on Priority
Areas “Reaction Control of Dynamic Complex” and “Synergy
of Elements for Creation of Functional Molecules,” and COE
Research on “United Approach to New Material Science”
from MEXT. AKS thanks JSPS for the award of a postdoctoral
fellowship.

J. Chen et al.
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