Palladium-imidazolinium carbene-catalyzed arylation of aldehydes with arylboronic acids in water

Article abstract of DOI:10.1016/j.tet.2010.06.049

The catalytic arylation of aldehydes with arylboronic acids in only water was found to be achieved using the palladium/thioether-imidazolinium chloride system in good to excellent yields. This catalytic process showed high tolerance for a broad range of substrates, giving a variety of carbinol derivatives with 2.0-3.0 mol % of the catalyst.

Full text of DOI:10.1016/j.tet.2010.06.049

Tetrahedron 66 (2010) 6814e6819
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Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Palladium-imidazolinium carbene-catalyzed arylation of aldehydes
with arylboronic acids in water
*
*
Masami Kuriyama , Natsuki Ishiyama, Rumiko Shimazawa, Osamu Onomura
Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 28 April 2010
Received in revised form 21 June 2010
Accepted 21 June 2010
Available online 25 June 2010
The catalytic arylation of aldehydes with arylboronic acids in only water was found to be achieved using
the palladium/thioether-imidazolinium chloride system in good to excellent yields. This catalytic process
showed high tolerance for a broad range of substrates, giving a variety of carbinol derivatives with
2.0e3.0 mol % of the catalyst.
Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction
there is still room for improvement in reaction systems and
substrate generality.
Powerful and environmentally benign synthetic methods are
desirable from the viewpoint of green chemistry.1 Organic chem-
ical reactions in aqueous media have been focused due to various
advantages of water as a solvent, such as its low cost, safety, and
innocuousness in addition to unique reactivity observed in it.2,3
Especially, the discovery and development of more efficient and
sustainable transition-metal catalysts that are effective in only
water has been still desired.4 However, the achievement of high
selectivity and yields with metal catalysts in water is not easy.2b,4a
In order to overcome the poor solubility of compounds and del-
eterious effects for metal catalysts in pure water, the aids of
ingenious methods such as sonication, microwave heating, organic
co-solvents, surfactants, and ligands with hydrophilic auxiliaries
are often necessary.2,4
More recently, we have developed thioether-imidazolinium
salts 1 as heterobidentate ligand precursors (Fig. 1).12 In the course
of our investigation on the palladium-catalyzed 1,2-addition of
organoboron reagents with N-heterocyclic carbene precursors 1,13
we found the palladium/thioether-imidazolinium chloride system
had the ability to tolerate water and achieved high catalyst per-
formance even in the arylation of aldehydes using arylboronic acids
in only water without further assistance such as co-solvents, sur-
factants, and hydrophilic auxiliaries. Herein, we would like to
describe the full details on this investigation.
CI
Transition metal catalysts are one of the most important tools
for CꢀC bond formation.5 Since Miyaura and co-workers found
the rhodium-catalyzed 1,2-addition to aldehydes in 1998,6
transition metal-catalyzed arylation of aldehydes with organo-
boron reagents have attracted much attention.7 Because of the
advantages of organoboron reagents, such as low toxicity and easy
manipulation,8 several types of active catalysts have been
developed for this kind of reaction.9,10 In spite of these efforts,
only two examples of transition metal-catalyzed arylation of
aldehydes with organoboron reagents in only water have been
reported.11 Sweigart found the anionic rhodium quinonoid cata-
lyst was effective,11a and Wu developed the cyclopalladated
complex-catalyzed arylation of aldehydes with SDS.11b However,
Figure 1. Precursors of N-heterocyclic carbene ligands.
2. Results and discussion
Our initial study was focused on optimization of reaction con-
ditions using 2-naphthaldehyde 2a and phenylboronic acid 3a
(Table 1). The 1,2-addition with 1.0 mol % of the catalysts generated
in situ from thioether-imidazolinium chloride 1aef and allylpalla-
dium(II) chloride dimer in the presence of cesium carbonate was
examined in water at 100 ꢁC for 2 h. Then, only thioether-imidazo-
linium chloride 1e was proven to be an effective N-heterocyclic
carbene ligand precursor (entries 1e6). The arylation reactions at 80
and 120 ꢁC led to decrease in yields, affording the adduct 4aa with
45% and 73% yields, respectively (entries 7 and 8). The screening of
palladium sources was conducted, and allylpalladium(II) chloride
dimer showed the highest catalytic activity (entries 5 and 9e12).
* Corresponding authors. E-mail addresses: mkuriyam@nagasaki-u.ac.jp
(M. Kuriyama), onomura@nagasaki-u.ac.jp (O. Onomura).
0040-4020/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2010.06.049

M. Kuriyama et al. / Tetrahedron 66 (2010) 6814e6819
6815
While the examination of bases revealed that cesium carbonate was
the reagent of choice, cheaper potassium carbonate and sodium
carbonate also provided good results (entries 5 and 13e18). Evalu-
ation on the effect of organic solvents gave the information that the
smooth reaction progress required the appropriate solvent polarity
(entries 19e21). Interestingly, DMSO gave the quite poor result
although the reaction in more highly polar water proceeded effi-
ciently, which could be achieved by hydrophobic effects. As expec-
ted, the decrease of water had no influence on the reaction rate,
which could make the large-scale synthesis easier to conduct (entry
22). The gram-scale reaction with 10 mmol of the aldehyde 2a was
achieved with excellent efficacy to afford the desired product 4aa in
91% yield (entry 23). Thus, this catalytic system could be quite
advantageous for the practical synthesis of carbinol derivatives.
afford 61% yield (entry 5), the 1,2-addition reaction of electron-
poor arylboronic acid 3g proceeded efficiently with 96% yield
(entry 6). In addition, heteroarylboronic acids were examined. The
arylation reactions using 1-methyl-5-indolylboronic acid 3h and
3-thiopheneboronic acid 3i gave the products 4ah and 4ai in 55%
and 76% yields, respectively (entries 7 and 8).
Table 2
Palladium-imidazolinium carbene-catalyzed arylation of 2-naphthaldehyde in
watera
1e
O
OH
Ar
[Pd(allyl)Cl]2
+
(HO)2BAr
H
Cs2CO3
H2O
100 °C, 2 h
(1.5 equiv)
2a
3b-i
4
Table 1
Entry
1
(HO)2BAr
Product
Yieldb (%)
81
Optimization of Reaction Conditionsa
4ab
4ac
2
85
35
61
Entry
Ligand
Pd
Base
Yieldb (%)
3c
4
4ad
4ae
1
2
3
4
1a
1b
1c
1d
1e
1f
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
PdCl2
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
K2CO3
Na2CO3
BaCO3
CaCO3
CsF
0
5
20
9
90
13
45
73
5
5
6
7c
1e
1e
1e
1e
1e
1e
1e
1e
1e
1e
1e
1e
1e
1e
1e
1e
1e
8d
9
5
6
4af
61
96
10
11
12
13
14
15
16
17
18
19e
20f
21g
22h
23i
Pd(OAc)2
Pd(dba)2
Pd2(dba)3
6
33
36
78
80
33
43
27
60
90
95
25
90
91
4ag
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
[Pd(allyl)Cl]2
7
4ah
4ai
55
76
K3PO4
8
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
a
Reaction conditions: 2-naphthaldehyde 2a (1.0 mmol), arylboronic acid
3
(1.5 mmol), 1e (2.0 mol %), [Pd(allyl)Cl]2 (1.0 mol %), Cs2CO3 (2.0 mmol), water
(2 mL), 100 ꢁC, 2 h.
b
Isolated yield.
The catalyst (3.0 mol %) was used.
a
c
Reaction conditions: 2-naphthaldehyde 2a (1.0 mmol), phenylboronic acid 3a
(1.5 mmol), ligand (1.0 mol %), Pd (1.0 mol %), base (2.0 mmol), water (2 mL), 100 ꢁC,
2 h.
b
The influence of varying aldehydes in the 1,2-addition reactions
of phenylboronic acid 3a with 2.0 mol % of the catalyst was also
investigated (Table 3). In the case of the reaction using 2-naph-
thaldehyde 2a with 2.0 mol % catalyst loading, the result was
slightly improved to afford 93% yield (entry 1). The sterically hin-
dered aromatic aldehydes 2b and 2c led to the excellent yields
(entries 2 and 3). Then, no significant decrease in yields for the
arylation of electron-rich aromatic aldehydes such as 2d, 2e, and 2f
was observed, giving the desired products 4daefa in high yields
(entries 4e6). The 1,2-addition to the electron-poor aromatic
aldehyde 2g proceeded smoothly with 99% yield (entry 7). Both of
4-chlorobenzaldehyde 2h and 2,4-dichlorobenzaldehyde 2i were
converted efficiently without the generation of Suzuki/Miyaura
coupling or dehalogenation products (entries 8 and 9).14 Other
electron-withdrawing functionalities such as nitro, cyano, and
acetyl groups were also tolerated under the reaction conditions
(entries 10e12), though they have high reactivity toward Grignard
or organolithium reagents. In the reaction using tereph-
thalaldehyde 2m, the monophenylated product 4ma was formed
with 80% yield, while the diphenylated compound 5ma15 was
Isolated yield.
c
The reaction was carried out at 80 ꢁC.
d
The reaction was carried out at 120 ꢁC.
e
Toluene was used as a solvent.
Dioxane was used as a solvent.
DMSO was used as a solvent.
1 mL of water was used as a solvent.
f
g
h
i
Large-scale reaction conditions: 2-naphthaldehyde 2a (10 mmol), phenyl-
boronic acid 3a (15 mmol), 1e (1.0 mol %), Pd (1.0 mol %), Cs2CO3 (20 mmol), water
(15 mL), 100 ꢁC, 8 h.
Investigation of arylboronic acids in the arylation reactions of
2-naphthaldehyde 2a with 2.0 mol % of the catalyst was examined
(Table 2). The reactions using 4-methylphenylboronic acid 3b or
3-methylphenylboronic acid 3c took place smoothly to give the
desired products in high yields (entries 1 and 2). On the other
hand, sterically hindered 2-methylphenylboronic acid 3d led to
35% yield (entry 3). The arylation with 1-naphthylboronic acid 3e
gave the adduct 4ae in moderate yield (entry 4). While the elec-
tron-rich 4-methoxyphenylboronic acid 3f was less reactive to

6816
M. Kuriyama et al. / Tetrahedron 66 (2010) 6814e6819
Table 3
3. Conclusion
Palladium-imidazolinium carbene-catalyzed phenylation of aldehydes in watera
1e
In summary, we found the thioether-imidazolinium chloride 1e
led to the high level of catalyst performance for the palladium-
catalyzed 1,2-addition of arylboronic acids to aldehydes even in
only water with no further aid. This process was carried out readily
with 2.0e3.0 mol % of catalyst loading, giving various carbinol
compounds bearing a diverse range of functionalities with good to
excellent yields.
OH
[Pd(allyl)Cl]2
O
+
(HO)2BPh
(1.5 equiv)
3a
R
R
H
Cs2CO3
H2O
100 °C, 2 h
2a-p
4
Entry
1
RCHO
Product
Yieldb (%)
93
4aa
4. Experimental
4.1. General
2
3
4ba
4ca
95
92
All melting points are not corrected. 1H NMR spectra were taken
at 300 or 400 MHz. 13C NMR spectra were taken at 75 or 100 MHz.
Chemical shift values are expressed in parts per million relative to
internal or external TMS. Abbreviations are as follows: s, singlet; d,
doublet; t, triplet; q, quartet; m, multiplet; br, broad. Mass spectra
(MS) and high-resolution mass spectra (HRMS) were recorded us-
ing electron ionization (EI) mass spectrometry. The products were
isolated by silica gel column chromatography. Organoboronic acids
and palladium sources were used as received. Degassed ultrapure
water was used as a solvent. Cesium carbonate, potassium car-
bonate, sodium carbonate, calcium carbonate, barium carbonate,
and cesium fluoride were used as received. Potassium phosphate
tribasic was ground to a fine powder prior to use.
4c
5
4da
4ea
81
99
6c
4fa
78
4.2. General procedure for the palladium-imidazolinium
carbene-catalyzed arylation of aldehydes with arylboronic
acids in water
7
8
9
4ga
4ha
4ia
99
92
92
Under an argon atmosphere, a reaction tube was charged with
thioether-imidazolinium chloride 1e (9.02 mg, 0.02 mmol), [Pd
(allyl)Cl]2 (3.66 mg, 0.01 mmol), and cesium carbonate (652 mg,
2.0 mmol). To this mixture was added water (2.0 mL). The mixture
was stirred for 15 min at 80 ꢁC and cooled to room temperature.
Then, aldehyde (1.0 mmol) and arylboronic acid (1.5 mmol) were
added, and the reaction mixture was stirred at 100 ꢁC for 2 h. The
mixture was cooled to room temperature. Water and saturated
NH4Cl were added and the resulting mixture was extracted with
AcOEt. The combined organic layers were washed with brine, and
then dried over MgSO4. Concentration and purification through
silica gel column chromatography gave the product.
10
11
12
4ja
4ka
4la
93
87
94
13d
14c
15
4ma
4na
4oa
80
96
92
4.2.1. 4-Methylphenyl(2-naphthyl)methanol10a (4ab) (Table 2, entry
1). Silica gel column chromatography (hexane/AcOEt¼10/1) gave
200 mg (0.81 mmol, 81% yield) of the product as a colorless solid of
mp 91e92 ꢁC. IR (neat): 3300 cmꢀ1. 1H NMR (400 MHz, CDCl3): 2.32
(br s, 4H), 5.95 (s, 1H), 7.12e7.14 (m, 2H), 7.22e7.29 (m, 2H),
7.39e7.49 (m, 3H), 7.74e7.88 (m, 4H). 13C NMR (100 MHz, CDCl3):
21.1, 76.2, 124.8, 124.9, 125.9, 126.1, 127.0, 127.6, 128.1, 128.2, 129.2,
132.8, 133.3, 137.4, 140.8, 141.3. EIMS m/z: 248 (Mþ).
16c
4pa
93
a
4.2.2. 3-Methylphenyl(2-naphthyl)methanol (4ac) (Table 2, entry
2). Silica gel column chromatography (hexane/AcOEt¼10/1) gave
211 mg (0.85 mmol, 85% yield) of the product as a colorless solid of
mp 77e78 ꢁC. IR (neat): 3330 cmꢀ1. 1H NMR (400 MHz, CDCl3): 2.28
(s, 1H), 2.33 (s, 3H), 5.97 (s, 1H), 7.09 (d, J¼5.8 Hz, 1H), 7.23 (d,
J¼5.8 Hz, 3H), 7.41e7.50 (m, 3H), 7.78e7.85 (m, 3H), 7.91 (s, 1H). 13C
NMR (100 MHz, CDCl3): 21.4, 76.3, 123.8, 124.8, 124.9, 125.9, 126.1,
127.3, 127.6, 128.0, 128.2, 128.4, 132.8, 133.2, 138.2, 141.2, 143.6.
HRMS (EI) m/z: calcd for C18H16O (Mþ): 248.1201. Found: 248.1189.
Reaction conditions: aldehyde 2 (1.0 mmol), phenylboronic acid 3a (1.5 mmol),
ligand 1e (2.0 mol %), [Pd(allyl)Cl]2 (1.0 mol %), Cs2CO3 (2.0 mmol), water (2 mL),
100 ꢁC, 2 h.
b
Isolated yield.
The catalyst (3.0 mol %) was used.
1,4-Bis(phenylhydroxylmethyl)benzene 5ma was obtained in 17% yield as
c
d
a side product.
observed in 17% yield (entry 13). The arylation of the aliphatic
aldehyde 2n took place without difficulty with excellent yield
(entry 14). The heteroaromatic aldehydes 2o and 2p were also
proved to be good acceptors, affording the addition products 4oa
and 4pa in high yields (entries 15 and 16).
4.2.3. 2-Methylphenyl(2-naphthyl)methanol13b (4ad) (Table 2, entry
3). Silica gel column chromatography (hexane/AcOEt¼10/1) gave

M. Kuriyama et al. / Tetrahedron 66 (2010) 6814e6819
6817
87 mg (0.35 mmol, 35% yield) of the product as a colorless solid of
mp 77e78 ꢁC. IR (neat): 3310 cmꢀ1. 1H NMR (400 MHz, CDCl3): 2.22
(s, 1H), 2.30 (s, 3H), 6.18 (s, 1H), 7.15e7.27 (m, 3H), 7.40e7.42 (m,
1H), 7.45e7.48 (m, 2H), 7.52e7.55 (m, 1H), 7.78e7.81 (m, 4H). 13C
NMR (100 MHz, CDCl3): 19.4, 73.4, 125.2, 125.6, 125.9, 126.08,
126.12, 126.5, 127.6, 128.0, 128.2, 130.6, 132.8, 133.2, 135.5, 140.2,
141.2. EIMS m/z: 248 (Mþ).
(100 MHz, CDCl3): 76.2, 124.7, 125.0, 125.9, 126.1, 126.6, 127.5, 127.6,
128.0, 128.2, 128.4, 132.8, 133.2, 141.1, 143.6. EIMS m/z: 234 (Mþ).
4.2.10. 1-Naphthyl(phenyl)methanol10q (4ba) (Table 3, entry 2). Sil-
ica gel column chromatography (hexane/AcOEt¼10/1) gave 222 mg
(0.95 mmol, 95% yield) of the product as yellow oil. IR (neat):
3700 cmꢀ1. 1H NMR (400 MHz, CDCl3): 2.60 (br s, 1H), 6.43 (s, 1H),
7.20e7.28 (m, 3H), 7.32e7.43 (m, 5H), 7.55 (d, J¼7.0 Hz, 1H), 7.75 (d,
J¼8.0 Hz, 1H), 7.81 (d, J¼7.0 Hz, 1H), 7.96 (d, J¼8.0 Hz, 1H). 13C NMR
(100 MHz, CDCl3): 73.5, 124.0, 124.6, 125.3, 125.5, 126.0, 127.0, 127.5,
128.36, 128.41, 128.7, 130.7, 133.9, 138.8, 143.1. EIMS m/z: 234 (Mþ).
4.2.4. 1-Naphthyl(2-naphthyl)methanol (4ae) (Table 2, entry 4).
Silica gel column chromatography (hexane/AcOEt¼10/1) gave
172 mg (0.61 mmol, 61% yield) of the product as a colorless solid of
mp 107e108 ꢁC. IR (neat): 3480 cmꢀ1. 1H NMR (400 MHz, CDCl3):
2.43 (s, 1H), 6.70 (s, 1H), 7.42e7.51 (m, 6H), 7.65 (d, J¼7.1 Hz, 1H),
7.77e7.88 (m, 5H), 7.93 (s, 1H), 8.11 (d, J¼7.8 Hz, 1H). 13C NMR
(100 MHz, CDCl3): 73.6,124.0,124.9,125.1,125.3, 125.6, 125.6, 126.0,
126.1, 126.2, 127.6, 128.1, 128.2, 128.6, 128.7, 130.8, 132.9, 133.3,
134.0, 138.6, 140.5. HRMS (EI) m/z: calcd for C21H16O (Mþ):
284.1201. Found: 284.1183.
4.2.11. 2-Biphenyl(phenyl)methanol (4ca) (Table 3, entry 3). Silica
gel column chromatography (hexane/AcOEt¼10/1) gave 239 mg
(0.92 mmol, 92% yield) of the product as colorless oil. IR (neat):
3590 cmꢀ1.1H NMR (400 MHz, CDCl3): 2.04 (br s,1H), 5.94 (s,1H), 7.17
(d, J¼7.1 Hz, 2H), 7.21e7.27 (m, 6H), 7.31e7.41 (m, 5H), 7.56 (d,
J¼7.6 Hz, 1H). 13C NMR (100 MHz, CDCl3): 72.1, 126.5, 126.9, 127.0,
127.1, 127.2, 127.7, 128.04, 128.09, 129.2, 129.8, 140.7, 140.9, 141.1, 143.8.
HRMS (EI) m/z: calcd for C19H16O (Mþ): 260.1201. Found: 260.1192.
4.2.5. 4-Methoxyphenyl(2-naphthyl)methanol13b (4af) (Table 2,
entry 5). Silica gel column chromatography (hexane/AcOEt¼10/
1) gave 161 mg (0.61 mmol, 61% yield) of the product as ꢀa1 col-
4.2.12. 4-Methoxyphenyl(phenyl)methanol10a (4da) (Table 3, entry
4). Silica gel column chromatography (hexane/AcOEt¼20/1) gave
173 mg (0.81 mmol, 81% yield) of the product as colorless oil. IR
orless solid of mp 78e79 ꢁC. IR (neat): 1250, 3390 cm
.
1H
NMR (400 MHz, CDCl3): 2.27 (s, 1H), 3.79 (s, 3H), 5.97 (s, 1H),
6.87 (d, J¼8.8 Hz, 2H), 7.32 (d, J¼8.8 Hz, 2H), 7.41 (d, J¼8.8 Hz,
1H), 7.46e7.47 (m, 2H), 7.78e7.85 (m, 3H), 7.90 (s, 1H). 13C
NMR (100 MHz, CDCl3): 55.3, 75.9, 113.9, 124.7, 125.9, 126.1,
127.6, 128.0, 128.1, 128.2, 132.8, 133.2, 136.0, 141.3, 159.1. EIMS
m/z: 264 (Mþ).
(neat): 1170, 3570 cmꢀ1 1H NMR (300 MHz, CDCl3): 2.14 (d,
.
J¼3.3 Hz,1H), 3.79 (s, 3H), 5.82 (d, J¼3.3 Hz,1H), 6.84e6.89 (m, 2H),
7.26e7.39 (m, 7H). 13C NMR (75 MHz, CDCl3): 55.2, 75.8, 113.9,
126.4, 127.3, 127.9, 128.4, 136.2, 144.0, 159.0. EIMS m/z: 214 (Mþ).
4.2.13. 3-Methoxyphenyl(phenyl)methanol10e (4ea) (Table 3, entry
5). Silica gel column chromatography (hexane/AcOEt¼10/1) gave
212 mg (0.99 mmol, 99% yield) of the product as colorless oil. IR
4.2.6. 4-Fluorophenyl(2-naphthyl)methanol13b (4ag) (Table 2, entry
6). Silica gel column chromatography (hexane/AcOEt¼10/1) gave
243 mg (0.96 mmol, 96% yield) of the product as a colorless solid of
(neat): 1260, 3480 cmꢀ1 1H NMR (300 MHz, CDCl3): 2.21 (d,
.
mp 67e68 ꢁC. IR (neat): 1220, 3300 cmꢀ1
.
1H NMR (300 MHz,
J¼3.3 Hz, 1H), 3.79 (s, 3H), 5.82 (d, J¼3.3 Hz,1H), 6.79e6.82 (m, 1H),
6.94e6.97 (m, 2H), 7.22e7.40 (m, 6H). 13C NMR (75 MHz, CDCl3):
55.0, 76.0, 111.9, 112.8, 118.7, 126.4, 127.4, 128.3, 129.3, 143.5, 145.3,
159.6. EIMS m/z: 214 (Mþ).
CDCl3): 2.31 (br s,1H), 6.00 (s,1H), 6.99e7.05 (m, 2H), 7.36e7.40 (m,
3H), 7.44e7.51 (m, 2H), 7.79e7.85 (m, 3H), 7.87 (s, 1H). 13C NMR
(100 MHz, CDCl3): 75.6, 115.3 (d, J¼22.2 Hz), 124.6, 125.0, 126.1,
126.3, 127.7, 128.0, 128.4 (d, J¼8.2 Hz), 132.9, 133.2, 139.4, 141.0,
162.2 (d, J¼244.5 Hz). EIMS m/z: 252 (Mþ).
4.2.14. 3,4-Methylenedioxyphenyl(phenyl)methanol13a (4fa) (Table 3,
entry 6). Silica gel column chromatography (hexane/AcOEt¼10/1)
gave 178 mg (0.78 mmol, 78% yield) of the product as yellow oil. IR
(neat): 3390 cmꢀ1. 1H NMR (400 MHz, CDCl3): 2.15 (s, 1H), 5.77 (s,
1H), 5.93 (s, 2H), 6.76 (d, J¼8.3 Hz, 1H), 6.85e6.86 (m, 2H),
7.26e7.28 (m, 1H), 7.32e7.38 (m, 4H). 13C NMR (100 MHz, CDCl3):
75.8, 100.9, 107.1, 107.9, 119.9, 126.2, 127.4, 128.3, 138.0, 143.8, 146.8,
147.7. EIMS m/z: 228 (Mþ).
4.2.7. (1-Methyl-5-indolyl)(2-naphthyl)methanol13a (4ah) (Table 2,
entry 7). Silica gel column chromatography (hexane/AcOEt¼10/1)
gave 157 mg (0.55 mmol, 55% yield) of theꢀp1roduct as a colorless
solid of mp 92e93 ꢁC. IR (neat): 3450 cm
.
1H NMR (400 MHz,
CDCl3): 2.29 (s, 1H), 3.77 (s, 3H), 6.13 (s, 1H), 6.46 (d, J¼3.0 Hz, 1H),
7.05 (d, J¼3.0 Hz, 1H), 7.23e7.30 (m, 2H), 7.42e7.49 (m, 3H), 7.67 (s,
1H), 7.76e7.85 (m, 3H), 7.97 (s, 1H). 13C NMR (100 MHz, CDCl3):
32.7, 76.7, 101.1, 109.4, 119.3, 120.9, 124.6, 125.0, 125.7, 125.9, 127.7,
127.9, 128.0 128.3, 129.3, 132.7, 133.2, 135.0, 136.2, 141.9. EIMS m/z:
287 (Mþ).
4.2.15. 4-Fluorophenyl(phenyl)methanol10a (4ga) (Table 3, entry 7).
Silica gel column chromatography (hexane/AcOEt¼10/1) gave
200 mg (0.99 mmol, 99% yield) of the product as a colorless solid of
mp 42e43 ꢁC. IR (neat): 3310 cmꢀ1. 1H NMR (400 MHz, CDCl3): 2.71
(br s, 1H), 5.68 (s, 1H), 6.93e6.97 (m, 2H), 7.23e7.28 (m, 7H). 13C
NMR (100 MHz, CDCl3): 75.5, 115.2 (d, J¼21.4 Hz), 126.4, 127.7, 128.2
(d, J¼8.2 Hz), 128.5, 139.5 (d, J¼2.5 Hz), 143.6, 162.1 (d, J¼244.5 Hz).
EIMS m/z: 202 (Mþ).
4.2.8. 3-Thienyl(2-naphthyl)methanol13a (4ai) (Table 2, entry 8).
Silica gel column chromatography (hexane/AcOEt¼10/1) gave
183 mg (0.76 mmol, 76% yield) of the product as colorless oil. IR
(neat): 3300 cmꢀ1. 1H NMR (400 MHz, CDCl3): 2.38 (br s, 1H), 6.02
(s, 1H), 7.00 (d, J¼4.9 Hz, 1H), 7.18e7.27 (m, 2H), 7.43e7.48 (m, 3H),
7.79e7.86 (m, 4H). 13C NMR (100 MHz, CDCl3): 72.7, 121.7, 124.6,
124.9, 125.9, 126.08, 126.13, 126.4, 127.6, 128.0, 128.2, 132.9, 133.1,
140.7, 145.1. EIMS m/z: 240 (Mþ).
4.2.16. 4-Chlorophenyl(phenyl)methanol10h (4ha) (Table 3, entry 8).
Silica gel column chromatography (hexane/AcOEt¼10/1) gave
200 mg (0.92 mmol, 92% yield) of the product as a colorless solid of
mp 55e56 ꢁC. IR (neat): 3310 cmꢀ1. 1H NMR (400 MHz, CDCl3): 2.24
(s, 1H), 5.81 (s, 1H), 7.27e7.35 (m, 9H). 13C NMR (100 MHz, CDCl3):
75.3, 126.4, 127.7, 127.8, 128.4, 128.5, 133.1, 142.1, 143.3. EIMS m/z:
218 (Mþ, 35Cl).
4.2.9. 2-Naphthyl(phenyl)methanol13b (4aa) (Table 3, entry 1). Silica
gel column chromatography (hexane/AcOEt¼10/1) gave 218 mg
(0.93 mmol, 93% yield) of the product as a colorless solid of mp
87e88 ꢁC. IR (neat): 3560 cmꢀ1. 1H NMR (400 MHz, CDCl3): 2.31 (br
s, 1H), 6.02 (s, 1H), 7.28e7.29 (m, 1H), 7.35 (m, 2H), 7.42e7.44 (m,
3H), 7.46e7.49 (m, 2H), 7.78e7.85 (m, 3H), 7.90 (s, 1H). 13C NMR
4.2.17. 2,4-Dichlorophenyl(phenyl)methanol10h (4ia) (Table 3, entry
9). Silica gel column chromatography (hexane/AcOEt¼20/1) gave

6818
M. Kuriyama et al. / Tetrahedron 66 (2010) 6814e6819
232 mg (0.92 mmol, 92% yield) of the product as colorless oil. IR
122.3, 123.5, 124.1, 124.2, 126.4, 128.1, 128.5, 139.3, 139.8, 142.5,
(neat): 3290 cmꢀ1
.
1H NMR (300 MHz, CDCl3): 2.30 (d, J¼4.0 Hz,
148.6. EIMS m/z: 240 (Mþ).
1H), 6.17 (d, J¼4.0 Hz, 1H), 7.26e7.38 (m, 7H), 7.59 (d, J¼8.4 Hz, 1H).
13C NMR (100 MHz, CDCl3): 72.1, 126.8, 127.3, 127.9, 128.5, 128.8,
129.1, 132.9, 133.7, 139.5, 141.7. EIMS m/z: 252 (Mþ, 35Clꢂ2).
4.2.25. 1,4-Bis(phenylhydroxymethyl)benzene (5ma) (Table 3, entry
13). Silica gel column chromatography (hexane/AcOEt¼20/1) gave
49 mg (0.17 mmol, 17% yield) of the product as a colorless solid of
mp 134e135 ꢁC. IR (neat): 3390 cmꢀ1. 1H NMR (400 MHz, CDCl3):
2.18 (d, J¼3.4 Hz, 2H), 5.83 (d, J¼3.4 Hz, 2H), 7.27e7.37 (m, 14H). 13C
NMR (100 MHz, CDCl3): 76.1, 126.5, 126.7, 127.6, 128.5, 143.2, 143.7.
HRMS (EI) m/z: calcd for C20H18O2 (Mþ): 290.1307. Found: 290.1316.
4.2.18. 4-Nitrophenyl(phenyl)methanol10e (4ja) (Table 3, entry 10).
Silica gel column chromatography (hexane/AcOEt¼10/1) gave
212 mg (0.93 mmol, 93% yield) of the product as a colorless solid of
mp 52e53 ꢁC. IR (neat): 1350, 1540, 3340 cmꢀ1. 1H NMR (400 MHz,
CDCl3): 2.39 (d, J¼2.4 Hz, 1H), 5.92 (d, J¼2.4 Hz, 1H), 7.31e7.39 (m,
5H), 7.58 (d, J¼8.3 Hz, 2H), 8.19 (d, J¼8.3 Hz, 2H). 13C NMR
(100 MHz, CDCl3): 75.2, 123.4, 126.5, 126.9, 128.1, 128.7, 142.5, 146.8,
150.8. EIMS m/z: 229 (Mþ).
4.3. Procedure for the large-scale synthesis of 2-naphthyl
(phenyl)methanol (Table 1, entry 23)
Under an argon atmosphere, a reaction tube was charged with
thioether-imidazolinium chloride 1e (45.1 mg, 0.1 mmol), [Pd(allyl)
Cl]2 (18.3 mg, 0.05 mmol), and cesium carbonate (6.52 g, 20 mmol).
To this mixture was added water (15 mL). The mixture was stirred
for 60 min at 80 ꢁC and cooled to room temperature. Then, 2-
naphthaldehyde (1.56 g, 10 mmol) and phenylboronic acid (1.83 g,
15 mmol) were added, and the reaction mixture was stirred at
100 ꢁC for 8 h. The mixture was cooled to room temperature. Water
and saturated NH4Cl were added and the resulting mixture was
extracted with AcOEt. The combined organic layers were washed
with brine, and then dried over MgSO4. Concentration and purifi-
cation through silica gel column chromatography (hexane/
AcOEt¼10/1) gave 2.12 g of 4aa (91% yield).
4.2.19. 4-Cyanophenyl(phenyl)methanol10e (4ka) (Table 3, entry
11). Silica gel column chromatography (hexane/AcOEt¼20/1) gave
181 mg (0.87 mmol, 87% yield) of the product as a colorless solid of
mp 58e59 ꢁC. IR (neat): 2240, 3660 cmꢀ1 1H NMR (400 MHz,
.
CDCl3): 3.05 (br s, 1H), 5.78 (s, 1H), 7.23e7.33 (m, 5H), 7.45 (d,
J¼8.3 Hz, 2H), 7.53 (d, J¼8.3 Hz, 2H). 13C NMR (100 MHz, CDCl3):
75.3, 110.7, 118.7, 126.5, 126.9, 128.0, 128.7, 132.1, 142.7, 148.9. EIMS
m/z: 209 (Mþ).
4.2.20. 4-Acetylphenyl(phenyl)methanol6b (4la) (Table 3, entry 12).
Silica gel column chromatography (hexane/AcOEt¼10/1) gave
212 mg (0.94 mmol, 94% yield) of the product as colorless oil. IR
(neat): 3330 cmꢀ1. 1H NMR (400 MHz, CDCl3): 2.40 (s, 1H), 2.57 (s,
3H), 5.89 (s, 1H), 7.26e7.37 (m, 5H), 7.49e7.51 (m, 2H), 7.91e7.93
(m, 2H). 13C NMR (100 MHz, CDCl3): 26.4, 75.5, 126.4, 126.5, 127.6,
128.4, 128.5, 135.8, 143.2, 149.2, 198.2. EIMS m/z: 226 (Mþ).
Acknowledgements
This research was supported by Grant-in-Aid for Scientific Re-
search (C) from Japan Society for the Promotion of Science (JSPS),
Grant-in-Aid for Young Scientists (B) from The Ministry of Edu-
cation, Culture, Sports, Science and Technology, Japan (MEXT),
Sasakawa Scientific Research Grant from The Japan Science Soci-
ety, SUNBOR GRANT from Suntory Institute for Bioorganic Re-
search, and Grant for Newly-Appointed Faculties from Nagasaki
University.
4.2.21. 4-Formylphenyl(phenyl)methanol10s (4ma) (Table 3, entry
13). Silica gel column chromatography (hexane/AcOEt¼20/1)
gave 170 mg (0.80 mmol, 80% yield) of the product as colorless
oil. IR (neat): 1710, 3490 cmꢀ1 1H NMR (400 MHz, CDCl3): 3.47
.
(br s, 1H), 5.83 (s, 1H), 7.23e7.32 (m, 5H), 7.52 (d, J¼8.3 Hz, 2H),
7.78 (d, J¼8.3 Hz, 2H), 9.89 (s, 1H). 13C NMR (100 MHz, CDCl3):
75.7, 126.6, 126.8, 127.9, 128.6, 129.9, 135.4, 143.0, 150.5, 192.1.
EIMS m/z: 212 (Mþ).
Supplementary data
4.2.22. Cyclohexyl(phenyl)methanol13a (4na) (Table 3, entry 14).
Silica gel column chromatography (hexane/AcOEt¼10/1) gave
182 mg (0.96 mmol, 96% yield) of the product as a colorless oil. IR
Supplementary data associated with this article can be found in
online version at doi:10.1016/j.tet.2010.06.049.
(neat): 3340 cmꢀ1 1H NMR (400 MHz, CDCl3): 0.85e1.26 (m, 5H),
.
1.33e1.37 (m, 1H), 1.53e1.65 (m, 3H), 1.72e1.76 (m, 1H), 1.94e1.97
(m, 1H), 2.14 (br s, 1H), 4.30 (d, J¼7.0 Hz, 1H), 7.23e7.32 (m, 5H). 13C
NMR (100 MHz, CDCl3): 25.9, 26.0, 26.4, 28.8, 29.2, 44.8, 79.2, 126.6,
127.2, 128.0, 143.6. EIMS m/z: 190 (Mþ).
References and notes
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€
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(400 MHz, CDCl3): 2.51 (s, 1H), 5.96 (s, 1H), 6.53 (s, 1H), 7.20e7.26
(m, 2H), 7.38e7.51 (m, 7H). 13C NMR (75 MHz, CDCl3): 70.6, 104.0,
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16). Silica gel column chromatography (hexane/AcOEt¼20/1)
gave 224 mg (0.93 mmol, 93% yield) of the product as a colorless
solid of mp 74e75 ꢁC. IR (neat): 3330 cmꢀ1 1H NMR (400 MHz,
.
CDCl3): 2.49 (d, J¼3.9 Hz, 1H), 6.13 (d, J¼3.9 Hz, 1H), 7.13 (s, 1H),
7.28e7.41 (m, 5H), 7.50 (d, J¼7.3 Hz, 2H), 7.68 (d, J¼7.3 Hz, 1H),
7.78 (d, J¼7.3 Hz, 1H). 13C NMR (100 MHz, CDCl3): 72.9, 121.1,

M. Kuriyama et al. / Tetrahedron 66 (2010) 6814e6819
6819
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