Decarboxylative photosubstitution of dicyanobenzenes with aliphatic carboxylate ions

Article abstract of DOI:10.1016/j.tet.2008.10.054

The photoreaction of dicyanobenzenes with aliphatic carboxylate ions afforded alkylcyanobenzenes and alkyldicyanobenzenes via decarboxylative substitution. The redox-photosensitized reaction system was effective in improving the product yield. The efficie

Full text of DOI:10.1016/j.tet.2008.10.054

Tetrahedron 65 (2009) 263–269
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Tetrahedron
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Decarboxylative photosubstitution of dicyanobenzenes with aliphatic
carboxylate ions
,
a
b
a,
*
Tatsuya Itou a, Yasuharu Yoshimi a , Toshio Morita , Yuji Tokunaga , Minoru Hatanaka
*
a Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
b Department of Materials Science and Engineering, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 1 October 2008
Received in revised form 20 October 2008
Accepted 20 October 2008
Available online 1 November 2008
The photoreaction of dicyanobenzenes with aliphatic carboxylate ions afforded alkylcyanobenzenes and
alkyldicyanobenzenes via decarboxylative substitution. The redox-photosensitized reaction system was
effective in improving the product yield. The efficiency of this photoreaction depended on the structure
of the carboxylate ion, and the product distribution varied with the dicyanobenzenes employed. This
photoreaction was proved to be a clean process for the preparation of alkylcyanobenzenes.
Ó 2008 Elsevier Ltd. All rights reserved.
1. Introduction
system,10 the substituted product of 1,4-dicyanobenzene was
obtained in a low yield.11 Although photosubstitution of 1,2,4,5-
Alkylcyanobenzenes are used as liquid crystal components1 and
as important synthetic intermediates in the preparation of func-
tionalized aromatic, heterocyclic, and polymeric materials.2 Al-
though several methods, which use metals such as Pd,3 Cu,4 and
pyridine transition metal complexes,5 have been developed for the
synthesis of alkylcyanobenzenes, photosubstitution of aromatic
nitriles is one of the most efficient and environmentally friendly
method since light is a clean and powerful reagent that can be used
to transform organic molecules.6–9 One such photosubstitution
reaction is the photo-NOCAS (nucleophile–olefin combination, ar-
omatic substitution) reaction of 1,4-dicyanobenzene with alkenes
that yields 4-alkyl-1-cyanobenzenes.6 Furthermore, the sub-
stitution of dicyanobenzenes with organosilanes, -germanes, and
-stannanes via a photoinduced electron transfer (PET) affords
a variety of alkylcyanobenzenes (Scheme 1).7,8
tetracyanobenzene with aliphatic carboxylic acids has been repor-
ted,12 the decarboxylative photosubstitution of dicyanobenzenes
has not yet been investigated. Thus, in this study, we endeavored
to investigate the decarboxylative photosubstitution of dicyano-
benzenes with a variety of aliphatic carboxylate ions for the
synthesis of alkylcyanobenzenes. The use of phenanthrene as
the photosensitizer resulted in an efficient photosubstitution in the
redox-photosensitized reaction system. This photoreaction tech-
nique can serve as a safe, economical, and environmentally friendly
method for the preparation of alkylcyanobenzenes.
2. Results and discussion
2.1. Decarboxylative photosubstitution of dicyanobenzenes
with aliphatic carboxylate ions via PET
CN
R
An aqueous acetonitrile solution (CH3CN/H2O¼9:1)13 containing
1,4-dicyanobenzene 1 (10 mM) and sodium hexanoate 2a (30 mM)
was irradiated with a 500-W high-pressure mercury lamp through
hν
CH3CN
+
R4M
M = Si, Ge, Sn
CN
CN
a Pyrex filter (l >300 nm) in an argon atmosphere for 6 h at room
Scheme 1. Photosubstitution of 1,4-dicyanobenzene with organosilanes, -germanes,
and -stannanes via a PET.
temperature. The process yielded 4-pentyl-1-cyanobenzene 3a
(49%) and 1 (27%) was recovered in isolated yields (Table 1, entry 1).
The use of the free acid (hexanoic acid) instead of 2a resulted in the
lower yield of 3a (28%); however, the addition of 1 equiv of NaOH to
this solution produced 3a in a yield similar to that obtained with 2a.
Thus, decarboxylation of the carboxylate ionwas more efficient than
that of the corresponding free carboxylic acid.
However, a less toxic process is still desired from an environ-
mental point of view. In the course of our studies involving the
decarboxylative reduction of carboxylic acids by a photogenerated
cation radical of phenanthrene in a redox-photosensitized reaction
Next, the photoreaction using various carboxylate ions was ex-
amined. Aliphatic, allylic, and benzylic carboxylate ions readily un-
derwent photosubstitution (entries 2–5), and the yield of 3 slightly
* Corresponding authors. Tel.: þ81 776 27 8633; fax: þ81 776 27 8747.
E-mail address: yoshimi@acbio2.acbio.fukui-u.ac.jp (Y. Yoshimi).
0040-4020/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2008.10.054

264
T. Itou et al. / Tetrahedron 65 (2009) 263–269
Table 1
Table 2
Decarboxylative photosubstitution of 1,4-dicyanobenzene 1 with carboxylate ions 2a
Decarboxylative photosubstitution of 1,2-dicyanobenzene 4 or 1,3-dicyanobenzene
7 with 2a
CN
CN
CN
CN
O
C
CN
hν
CN
+
CN
R
hν
CH3CN / H2O
= 9 : 1
R
ONa
2
+
+
CH CN / H2O
= 93: 1
CN
1
R
3
R
6
2
4
5
Entry
Carboxylate ion 2
Yieldb of 3 (%)
Recoveryb of 1 (%)
CN
CN
CN
1
2
3
4
5
6
7
8
9c
a; R¼pentyl
b; R¼c-hexyl
c; R¼t-butyl
49
55
61
38
37
0
0
0
80
27
31
10
10
20
95
82
95
0
hν
+
2
+
CH3CN / H2O
= 9 : 1
CN
R
CN
d; R¼CH2CH]CH2
e; R¼CH2Ph
f; R¼CH3
R
9
7
8
g; R¼CH]CH2
h; R¼Ph
Entry Dicyanobenzene
2
Product yieldsb (%)
Recoveryb of 4 or 7 (%)
b
5
6
8
9
a
The photoreaction was carried out with 1.2 mmol (10 mM) of 1 and 3.6 mmol
(30 mM) of 2 using a 500-W high-pressure mercury lamp under an argon atmo-
sphere for 6 h.
1
2
3
4
4
4
4
4
4
4
7
7
7
7
7
7
a
b
c
d
e
b
a
b
c
34
39
47
11
18
58
d
d
d
d
d
d
6
7
0
0
4
5
d
d
d
d
d
d
d
d
d
d
d
d
7
10
18
0
d
d
d
d
d
d
10
6
0
0
0
20
45
46
30
35
68
0
73
70
71
65
91
36
b
Isolated yield based on 1.
The photoreaction was carried out with 1.2 mmol (10 mM) of 1 and 7.2 mmol
c
5
6c
7
(60 mM) of 2b using a 500-W high-pressure mercury lamp under an argon atmo-
sphere for 12 h.
8
9
10
11
12c
d
e
b
increased in the following order: primary alkyl (49%)<secondary
alkyl (55%)<tertiaryalkyl carboxylate ions (61%). A similar trend was
also observed at the shorter irradiation time (2 h): primary alkyl
(27%)<secondary alkyl (41%)<tertiary alkyl carboxylate ions (46%).
The use of allylic and benzylic carboxylate ions 2d,e resulted in
relatively lower yields of 3 (entries 4 and 5). The photoproduct 3d
could subsequently photoreactwith 1tolowertheyield of3d. Infact,
3d was recovered in only 2% yield after the aqueous acetonitrile
solution containing 3d (5 mM) and 1 (5 mM) was irradiated for 6 h.
On the other hand, photoreactions of methyl, vinyl, and aromatic
carboxylate ions 2f–h did not produce the corresponding cyano-
benzenes 3, and 1 was recovered in 95%, 82%, and 95% yields, re-
spectively (entries 6–8). Higher concentration of 2b (60 mM) and
longer irradiation time (12 h) increased the yield of 3b (entry 9).
The use of 1,2-dicyanobenzene 4 in place of 1 in the photore-
action predominantly afforded 2-alkyl-1-cyanobenzene 5 in a low
yield, and the accompanied formation of 4-alkyl-1,2-dicyano-
benzene 6a,b,e was observed in the cases of 2a,b,e (Table 2, entries
1–5). To the best of our knowledge, this type of alkylation products
6 has never been isolated previously in similar photoreactions
when 4 was used as the electron acceptor.6–9 When 1,3-dicyano-
benzene 7 was subjected to this photoreaction, 3-alkyl-1-cyano-
benzene 8 and 4-alkyl-1,3-dicyanobenzene 9 were obtained in poor
yields, except in the cases when 2d,e were used (entries 7–11). The
formation of 9 has been observed only in the photoreaction of 7
with organoborates.14 In these photoreactions, higher concentra-
tion of 2b (120 mM) and longer irradiation time (24 h) also in-
creased the yield of substituted products (entries 6 and 12).
0
17
a
The photoreaction was carried out with 1.2 mmol (10 mM) of 4 or 7 and
3.6 mmol (30 mM) of 2 using a 500-W high-pressure mercury lamp under an argon
atmosphere for 6 h.
b
Isolated yield based on 4 or 7.
c
The photoreaction was carried out with 1.2 mmol (10 mM) of 4 or 7 and
14.4 mmol (120 mM) of 2b using a 500-W high-pressure mercury lamp under an
argon atmosphere for 24 h.
were recovered from this reaction (Table 3, entry1). The photore-
action between Phen and the carboxylate ion did not proceed in the
absence of 1.
Table 3
Decarboxylative photosubstitution of 1 with 2 in the presence of Phena
CN
+
CN
hν
1 + 2 +
3 +
CH3CN / H2O
= 9 : 1
10
11
Phen
Entry
2
Product yields (%)
Recoveryb of 1 (%)
3b
10c
11c
1
2
3
4
5
6
7
8
9e
a
b
c
d
e
f
g
h
b
31
7
12
6
1
40
28
5
2
64
68
76
53
0 (15)d
0
Trace
0
10
9
1
1
6
5 (11)d
0(0)d
0
90 (70)d
2.2. Decarboxylative photosubstitution of dicyanobenzenes
with aliphatic carboxylate ions in redox-photosensitized
reaction system
1
0
7
72
92
0
0
0
95
Trace
a
The photoreaction was carried out with 1.2 mmol (10 mM) of 1, 3.6 mmol
(30 mM) of 2, and 1.8 mmol (15 mM) of Phen using a 100-W high-pressure mercury
lamp under an argon atmosphere for 6 h.
Addition of phenanthrene (Phen) to the abovementioned sys-
tem accelerated the decarboxylative photosubstitution, and a low-
power light was adequate for this photoreaction. The photoreaction
of 1 (10 mM) with 2a (30 mM) in the presence of Phen (15 mM)
using a 100-W high-pressure mercury lamp through a Pyrex filter
b
Isolated yield based on 1.
Isolated yield based on Phen.
The values in parentheses are for the photoreaction using a 500-W high-pres-
c
d
sure mercury lamp for 12 h.
(l >300 nm) in an argon atmosphere for 6 h afforded three kinds of
e
The photoreaction was carried out with 1.2 mmol (10 mM) of 1, 7.2 mmol
products, 3a (31%), 9,10-dihydro-9-cyanophenanthrene 10 (7%),
and 9-cyanophenanthrene 11 (1%); further, 1 (40%) and Phen (76%)
(60 mM) of 2, and 1.8 mmol (15 mM) of Phen using a 100-W high-pressure mercury
lamp under an argon atmosphere for 12 h.

T. Itou et al. / Tetrahedron 65 (2009) 263–269
265
Table 4
2.3. Decarboxylative photosubstitution of dicyanobenzenes
with long-chain carboxylate ions
Decarboxylative photosubstitution of 4 or 7 with 2 in the presence of Phena
hν
6
4
2
5
10
11
Phen
CH3CN / H2O
= 9 : 1
In order to verify the effectiveness of the photoreaction, we
examined the photoreaction of dicyanobenzenes 1, 4, and 7 with
long-chain carboxylate ions 2i–j. The photoreaction of 1 with the
long-chain primary alkyl carboxylate ion 2i in the presence of Phen
afforded the corresponding alkylcyanobenzene 3i in a 25% yield
along with a small amount of the decarboxylative reduction product
12i (Table 5, entry 1). When D2O was used instead of water in the
mixed solvent system, the deuterated product of 12i was obtained
with a high d-content (>95%), indicating the intermediary forma-
tion of the corresponding anion followed byprotonation. In contrast,
the photoreaction of 1 with the long-chain secondary alkyl car-
boxylate ion 2j afforded 3j in 50% yield without the formation of 12j
(entry2). On the otherhand, the photoreaction of 4 with 2i yielded 5i
as a main substituted product, although higher yield of 12i was
obtained as well as in the case of photoreaction of 7 (entries 3 and 4).
hν
7
2
8
9
10
11
Phen
CH3CN / H2O
= 9 : 1
Entry Dicyanobenzene
2
Product yields (%)
Recoveryb of 4 or 7 (%)
5b 6b 8b 9b 10c 11c
1
2
3
4
5
6
7
8
9
10
4
4
4
4
4
7
7
7
7
7
a
b
c
d
e
a
b
c
32
38 17
6
d
d
d
d
d
d
d
d
d
d
20
4
Trace 15
11 Trace
14 Trace Trace
14 30
10 Trace 44
0
61
46
18
d
d
d
d
d
0
0
4
d
d
d
d
d
4
3
1
1
5
0
0
0
0
45
60
12 16
30
0
0
0
0
Trace 48
d
e
0
0
95
95
0
2.4. Mechanism
a
The photoreaction was carried out with 1.2 mmol (10 mM) of 4 or 7, 3.6 mmol
(30 mM) of 2, and 1.8 mmol (15 mM) of Phen using a 100-W high-pressure mercury
A plausible mechanism of this photoreaction in the absence and
presence of Phen is shown in Scheme 2. A similar mechanism has
been reported for the photoreaction between allylic/benzylic si-
lanes and dicyanobenzenes.7 The fluorescence of 1 in the aqueous
acetonitrile solution was efficiently quenched by 2a (kq¼4.1ꢀ
109 Mꢁ1 sꢁ1), as shown in Figure 1, indicating that PET from the
lamp under an argon atmosphere for 6 h.
b
Isolated yield based on 4 or 7.
Isolated yield based on Phen.
c
The photoreaction of the aliphatic, allylic, and benzylic carboxy-
late ions in the presence of Phen provided the higher yield of 3 as
compared to the photoreaction in the absence of Phen (entries 2–
5). In particular, the improved yield of 3d in the redox-photo-
sensitized reaction system could be ascribed to the suppression of
the secondary photoreaction of 3d with 1 (entry 4). Furthermore,
a high-power light (a 500-W high-pressure mercury lamp) and
a long irradiation time (12 h) led to the formation of 3f (entry 6, in
parenthesis). Therefore, we conclude that the presence of Phen
increased the efficiency of the photoreaction. In this reaction, the
following similar trend was observed in the yield of 3 from the
carboxylate ions: methyl, vinyl, and aromatic (0%)<primary alkyl
(31%)<secondary alkyl (64%)<tertiary alkyl carboxylate ions (68%).
Similar to the abovementioned system, higher concentration of 2b
(60 mM) and longer irradiation time (12 h) improved the yield of
3b (entry 9). The results of the photoreaction of 4 or 7 in the
presence of Phen, which are listed in Table 4, indicate a slight
improvement in the product yields of alkylcyanobenzenes 5 and 8,
and alkyldicyanobenzenes 6 and 9, and that the distribution of
their products is similar.
carboxylate ion
2 to the excited dicyanobenzenes occurred
smoothly to form the anion radicals of dicyanobenzenes 13 and the
carboxy radical 14 (Eq. 1). It has been confirmed from the Rehm–
Weller equation15 that PET is an exothermic process, as indicated by
the negative
D
G values (ꢁ141 kJ molꢁ1) that were calculated using
the reduction potential (1.64 V vs SCE)16 and excited singlet energy
(412 kJ molꢁ1 17
of 1 and the oxidation potential of 2a (1.16 V vs
)
SCE).18,19 In the presence of Phen, 14 is also formed by the oxidation
of 2 by the photogenerated cation radical of Phen, as reported
earlier (Eq. 2). The high efficiency of the redox-photosensitized
reaction system could be attributed to the higher absorption of
Phen at 313 nm as compared to that of dicyanobenzenes.
Since the rate of decarboxylation of 14 to 15 is dependent on the
stability of 15, the decarboxylation is very slow for methyl, alkenyl,
and aryl carboxy radicals. Thus, the decarboxylation of 2f–h does
not proceed efficiently, and 3 is not obtained in most cases. When
aliphatic carboxylate ions 2a–e are used, 14 is rapidly decarboxy-
lated to form 15. The generated alkyl radical 15 is coupled with 13,
Table 5
Decarboxylative photosubstitution of 1 or 4 or 7 with long-chain carboxylate ions 2i–j in the presence of Phena
CN
CN
CN
O
C
hν
+
+ 10 + 11
+
+
Phen
+
R
ONa
R
H(D)
12
CN
CH3CN / H2O
(D2O) = 9 : 1
R
CN
1 or 4or 7
R
2i-j
3 or 5 or8
6or9
Entry
Dicyanobenzene
2
Product yields (%)
12b
3c
5c
6c
8c
9c
10d
11d
1
2
3
4
1
1
4
7
i; R¼–(CH2)10OCH3
8
0
20
26
25
50
d
d
d
d
24
d
d
d
5
d
d
d
4
d
d
d
11
1
2
1
1
Trace
j; R¼–CH[(CH2)3CH3](CH2)5CH3
0
0
0
i
i
d
a
The photoreaction was carried out with 1.2 mmol (10 mM) of 1 or 4 or 7, 3.6 mmol (30 mM) of 2, and 1.8 mmol (15 mM) of Phen using a 100-W high-pressure mercury lamp
under an argon atmosphere for 6 h.
b
Isolated yield based on 2.
Isolated yield based on 1.
Isolated yield based on Phen.
c
d

266
T. Itou et al. / Tetrahedron 65 (2009) 263–269
decreased. This observation is substantiated by the high yield of
Formation of 13 and 14 in the absence of Phen
alkylcyanobenzene obtained in the photoreaction of 1 with 2b–d.
Radical 15 can also add to the dicyanobenzenes to form alkyl-
dicyanobenzenes 6 and 9 (Eq. 5);22 however, the detailed mecha-
nism of the formation of the alkyldicyanobenzenes 6 and 9 is
unclear and it is under investigation in our laboratory. As reported,
the cyanation of the cation radical of Phen in the presence of CNꢁ
yields 10 and 11 (Eq. 6).23
O
CN
*
CN
R
C
O
CN
+
O
C
hν
2
(1)
+
R
O
PET
14
CN
1 or 4 or 7
CN
13
CN
Formation of 13 and 14 in the presence of Phen
3. Conclusion
2
+
1 or 4or 7
hν
*
13 14
+
(2)
(3)
Phen +
R
13
Phen
+
Phen
R
Phen
In conclusion, we found that the decarboxylative photo-
substitution of dicyanobenzenes by carboxylate ions afforded
alkylcyanobenzenes and alkyldicyanobenzenes, irrespective of the
absence or presence of Phen. The product distribution depended on
the used dicyanobenzene, and the efficiency of this photoreaction
was strongly influenced by the structure of the carboxylate ion.
Since carboxylic acids are usually inexpensive and commercially
available, this photoreaction can prove to be useful in the synthesis
of alkylcyanobenzenes. The application of the generated radical to
organic synthesis is in progress in our laboratory.
PET
CN
decarbo-
xylation
O
+ 13
decyanation
CN
+
R
15
R
C
14
O
CN
3 or 5or 8
CN
+ 13
BET
H
(4)
(5)
R
15
R
H
12
R
CN
R
CN
4. Experimental section
4.1. General
e-
4or 7
H+
+
R
15
CN
R
CN
Melting points were taken on a hot stage apparatus and are
uncorrected. IR spectra were recorded on JASCO FT/IR-620, and GC–
MS spectra were obtained using a Shimadzu GCMS-QP5000. 1H and
13C NMR spectra were recorded on JEOL JNM-AL500 (500 and
125 MHz) spectrometer and for solutions in CDCl3 containing tet-
ramethylsilane as an internal standard. High resolution mass
spectra (HRMS) were obtained on JEOL JMS-700T. The light source
was Riko UV-100HA 100-W and Eiko-sha PIH 500-W high-pressure
mercury arc. Dicyanobenzenes 1, 4, and 7, and Phen were recrys-
tallized from hexane and EtOAc.
6 or 9
(6)
10
+
11
+
CN
Phen
Scheme 2. Plausible mechanism of the photoreaction in the absence and presence of
Phen.
and then undergoes decyanations to yield 3 or 5 or 8 and CNꢁ (Eq.
3). The efficiency of this substitution can vary according to the type
of dicyanobenzenes used. When 1,4-dicyanobenzene 1 is used,
radical 15 efficiently adds to its anion radical, thereby yielding 1-
alkyl-4-cyanobenzene 3 selectively; however, this addition is not
very effective when either 4 or 7 is used. In addition, a back electron
transfer (BET) from 13 to 15 results in the formation of an anion,
which is subsequently protonated by water to yield the reduction
product 12 (Eq. 4).20 In the photoreaction of 4 or 7, the low effi-
ciency of the substitution of 13 by 15 increases the BET, and the
yield of the substituted product 5 or 8 was lower. Furthermore,
since the efficiency of the anion formation from the primary alkyl
or benzyl radicals21 via BET is higher than that from the secondary
alkyl or tertiary alkyl or allylic radicals, the yield of 3 is drastically
4.2. Preparation of sodium carboxylate 2
Carboxylic acids (10 mmol) were added to a solution of NaOH
(10 mmol) in methanol (50 ml) and the mixture was refluxed for
2 h. After cooling to room temperature, ether (25 ml) was added to
the solution and filtered. The filtrate was dried in vacuo to afford
sodium carboxylates 2a–j in quantitative yields.
4.3. General procedure for the photoreaction of
dicyanobenzenes 1, 4, and 7 with 2
An aqueous acetonitrile solution (CH3CN/H2O¼9:1, 120 ml)
containing dicyanobenzenes 1, 4, and 7 (1.2 mmol) and sodium
carboxylate 2 (3.6 mmol) was irradiated with a 500-W high-pres-
sure mercury lamp through a Pyrex filter in an argon atmosphere
for 6 h at room temperature. The solution was filtered and evapo-
rated. Then, the residue was dissolved in EtOAc, washed with water,
dried over Na2SO4, and concentrated under reduced pressure to
afford the substituted products. These products were isolated by
silica gel column chromatography using hexane and EtOAc as elu-
ents and then by preparative HPLC using a GPC column.
4.3.1. 4-Pentyl-1-cyanobenzene 3a
Colorless oil; IR (neat) 2226 cmꢁ1 1H NMR (500 MHz, CDCl3)
;
d
7.56 (d, J¼8.2 Hz, 2H), 7.28 (d, J¼8.2 Hz, 2H), 2.66 (t, J¼7.6 Hz, 2H),
1.65–1.59 (m, 2H), 1.35–1.27 (m, 4H), 0.90 (t, J¼7.0 Hz, 3H); 13C NMR
(125 MHz, CDCl3)
d 148.6, 132.1, 129.2, 119.2, 109.5, 36.1, 31.3, 30.7,
22.5, 14.0; HRMS (FAB) calcd for (MþH)þ C12H16N: 174.1283, found:
Figure 1. Fluorescence quenching of
aqueous acetonitrile solution.
1
(1.0ꢀ10ꢁ5 M) by 2a excited at 270 nm in
174.1273.

T. Itou et al. / Tetrahedron 65 (2009) 263–269
267
4.3.2. 4-Cyclohexyl-1-cyanobenzene 3b9b
Colorless oil; IR (neat) 2224 cmꢁ1 1H NMR (500 MHz, CDCl3)
7.57 (d, J¼8.2 Hz, 2H), 7.30 (d, J¼8.2 Hz, 2H), 2.55 (br s, 1H), 1.87–
1.63 (m, 5H), 1.44–1.35 (m, 4H), 1.29–1.24 (m, 1H); 13C NMR
4.3.11. 4-Pentyl-1,2-dicyanobenzene 6a
Colorless oil; IR (neat) 2234 cmꢁ1
;
;
1H NMR (500 MHz, CDCl3)
d
d
7.72 (d, J¼8.2 Hz, 1H), 7.62 (s, 1H), 7.54 (d, J¼8.2 Hz, 1H), 2.72 (t,
J¼7.8 Hz, 2H), 1.68–1.60 (m, 2H), 1.37–1.30 (m, 4H), 0.92 (t, J¼7.0 Hz,
3H); 13C NMR (125 MHz, CDCl3)
149.6, 133.5, 133.4, 133.3, 115.8,
(125 MHz, CDCl3)
d
153.2, 132.2, 127.7, 119.2, 109.5, 44.8, 34.0, 26.6,
d
25.9; HRMS (FAB) calcd for (MþH)þ C13H16N: 186.1283, found:
115.6, 113.0, 35.7, 31.2, 30.3, 22.3, 13.9; HRMS (FAB) calcd for
186.1300.
(MþH)þ C13H15N2: 199.1236, found: 199.1282.
4.3.3. 4-tert-Butyl-1-cyanobenzene 3c24
4.3.12. 4-Cyclohexyl-1,2-dicyanobenzene 6b
Colorless oil; IR (neat) 2227 cmꢁ1
;
1H NMR (500 MHz, CDCl3)
White solid; mp 60–61 ꢂC; IR (KBr) 2233 cmꢁ1 1H NMR
;
d
7.59 (d, J¼8.2 Hz, 2H), 7.48 (d, J¼8.2 Hz, 2H), 1.33 (s, 9H); 13C NMR
(500 MHz, CDCl3)
d
7.71 (d, J¼8.2 Hz, 1H), 7.64 (s, 1H), 7.55 (d,
(125 MHz, CDCl3) d 156.6, 132.0, 126.1, 119.1, 109.3, 35.2, 30.9; HRMS
J¼8.2 Hz, 1H), 2.62 (br s, 1H), 1.90–1.78 (m, 4H), 1.42–1.25 (m, 6H);
(FAB) calcd for (MþH)þ C11H14N: 160.1127, found: 160.1145.
4.3.4. 4-Allyl-1-cyanobenzene 3d25
13C NMR (125 MHz, CDCl3)
d 154.3, 133.5, 132.1, 131.8, 115.9, 115.6,
113.1, 44.4, 33.7, 26.3, 25.6; HRMS (FAB) calcd for (MþH)þ C14H15N2:
211.1236, found: 211.1214.
Colorless oil; IR (neat) 2228 cmꢁ1 1H NMR (500 MHz, CDCl3)
;
d
7.59 (d, J¼8.2 Hz, 2H), 7.30 (d, J¼8.2 Hz, 2H), 5.96–5.88 (m, 1H),
4.3.13. 4-Benzyl-1,2-dicyanobenzene 6e
5.15–5.08 (m, 2H), 3.44 (d, J¼6.7 Hz, 2H); 13C NMR (125 MHz,
White solid; mp 104–105 ꢂC; IR (KBr) 2232 cmꢁ1 1H NMR
;
CDCl3)
d
145.6, 135.6, þ132.3, 129.4, 119.0, 117.2, 110.0, 40.1; HRMS
(500 MHz, CDCl3)
d
7.73 (d, J¼8.2 Hz, 1H), 7.59 (s, 1H), 7.55 (d,
(FAB) calcd for (MþH) C10H10N: 144.0813, found: 144.0814.
J¼8.2 Hz, 1H), 7.37–7.26 (m, 3H), 7.15 (d, J¼7.9 Hz, 2H), 4.08 (s, 2H);
13C NMR (125 MHz, CDCl3)
d 147.8, 137.7, 133.8, 133.6, 133.5, 129.2,
4.3.5. 4-Benzyl-1-cyanobenzene 3e26
129.0, 127.3, 116.1, 115.4, 113.5, 41.6; HRMS (FAB) calcd for (MþH)þ
Colorless oil; IR (neat) 2228 cmꢁ1
;
1H NMR (500 MHz, CDCl3)
C15H11N2: 219.0923, found: 219.0924.
d
7.57 (d, J¼8.2 Hz, 2H), 7.32–7.24 (m, 5H), 7.17–7.15 (m, 2H), 4.03 (s,
2H); 13C NMR (125 MHz, CDCl3)
d
146.7, 139.3, 132.3, 129.6, 128.9,
4.3.14. 3-Pentyl-1-cyanobenzene 8a
128.7, 126.6, 119.0, 110.0, 42.0; HRMS (FAB) calcd for (MþH)þ
Colorless oil; IR (neat) 2228 cmꢁ1 1H NMR (500 MHz, CDCl3)
;
C14H12N: 194.0970, found: 194.1010.
d
7.48–7.35 (m, 4H), 2.63 (t, J¼7.6 Hz,2H),1.64–1.58(m, 2H),1.38–1.31
(m, 4H), 0.90 (t, J¼7.0 Hz, 3H); 13C NMR (125 MHz, CDCl3)
d 144.2,
4.3.6. 2-Pentyl-1-cyanobenzene 5a
133.0, 132.0, 129.5, 129.0, 119.2, 112.2, 35.5, 31.3, 30.8, 22.5, 14.0;
Colorless oil; IR (neat) 2224 cmꢁ1
;
1H NMR (500 MHz, CDCl3)
HRMS (FAB) calcd for (MþH)þ C12H16N: 174.1283, found: 174.1284.
d
7.59 (d, J¼7.6 Hz, 1H), 7.52–7.47 (m, 1H), 7.52–7.47 (m, 2H), 2.83 (t,
J¼7.7 Hz, 2H),1.70–1.64 (m, 2H), 1.39–1.30 (m, 4H), 0.90 (t, J¼7.0 Hz,
3H); 13C NMR (125 MHz, CDCl3)
146.9, 132.8, 132.7, 129.5, 126.3,
4.3.15. 3-Cyclohexyl-1-cyanobenzene 8b
d
Colorless oil; IR (neat) 2227 cmꢁ1 1H NMR (500 MHz, CDCl3)
;
118.2, 112.3, 34.6, 31.4, 30.6, 22.4, 14.0; HRMS (FAB) calcd for
d
7.52–7.35 (m, 4H), 2.53 (br s, 1H), 1.87–1.76 (m, 5H), 1.42–1.38 (m,
(MþH)þ C12H16N: 174.1283, found: 174.1283.
4H), 1.27–1.10 (m, 1H); 13C NMR (125 MHz, CDCl3)
d
149.3, 131.6,
130.5, 129.6, 129.0, 119.3, 112.2, 44.2, 34.1, 26.6, 25.9; HRMS (FAB)
4.3.7. 2-Cyclohexyl-1-cyanobenzene 5b
calcd for (MþH)þ C13H16N: 186.1283, found: 186.1291.
Colorless oil; IR (neat) 2221 cmꢁ1 1H NMR (500 MHz, CDCl3)
;
d
7.60 (d, J¼7.6 Hz, 1H), 7.54–7.51 (m, 1H), 7.37 (d, J¼8.2 Hz, 1H),
7.28–7.25 (m, 1H), 3.00 (br s, 1H), 1.92–1.77 (m, 5H), 1.50–1.46
(m, 4H), 1.31–1.26 (m, 1H); 13C NMR (125 MHz, CDCl3)
151.5,
4.3.16. 3-tert-Butyl-1-cyanobenzene 8c
Colorless oil; IR (neat) 2229 cmꢁ1 1H NMR (500 MHz, CDCl3)
;
d
d
7.66 (s, 1H), 7.63 (d, J¼8.2 Hz, 1H), 7.48 (d, J¼6.4 Hz, 1H), 7.42 (m,
132.9, 132.8, 126.5, 126.3, 118.3, 111.8, 42.7, 33.7, 26.6, 25.9;
HRMS (FAB) calcd for (MþH)þ C13H16N: 186.1283, found:
186.1288.
1H), 1.33 (s, 9H); 13C NMR (125 MHz, CDCl3)
d 152.4, 130.0, 129.2,
129.1, 128.8, 119.4, 112.1, 34.9, 31.1; HRMS (FAB) calcd for (MþH)þ
C11H14N: 160.1127, found: 160.1135.
4.3.8. 2-tert-Butyl-1-cyanobenzene 5c
4.3.17. 4-Pentyl-1,3-dicyanobenzene 9a
Colorless oil; IR (neat) 2221 cmꢁ1
;
1H NMR (500 MHz, CDCl3)
White solid; mp 49–50 ꢂC; IR (KBr) 2235 cmꢁ1 1H NMR
;
d
7.67 (d, J¼7.6 Hz, 1H), 7.53–7.46 (m, 2H), 7.30–7.23 (m, 1H), 1.52 (s,
(500 MHz, CDCl3)
d
7.90 (s, 1H), 7.78 (d, J¼8.2 Hz, 1H), 7.48 (d,
9H); 13C NMR (125 MHz, CDCl3)
d
153.8, 135.6, 132.6, 126.3, 126.1,
J¼8.2 Hz, 1H), 2.91 (t, J¼7.6 Hz, 2H), 1.71–1.63 (m, 2H), 1.37–1.35 (m,
120.4, 110.7, 35.6, 30.2; HRMS (FAB) calcd for (MþH)þ C11H14N:
4H), 0.91 (t, J¼7.0 Hz, 3H); 13C NMR (125 MHz, CDCl3)
d 154.1, 136.1,
160.1127, found: 160.1099.
135.6, 130.6, 116.9, 115.9, 111.0, 34.9, 31.2, 30.6, 22.3, 13.8; HRMS
(FAB) calcd for (MþH)þ C13H15N2: 199.1236, found: 199.1247.
4.3.9. 2-Allyl-1-cyanobenzene 5d
Colorless oil; IR (neat) 2224 cmꢁ1
;
1H NMR (500 MHz, CDCl3)
4.3.18. 4-Cyclohexyl-1,3-dicyanobenzene 9b
d
7.63 (d, J¼7.6 Hz, 1H), 7.55–7.52 (m, 1H), 7.35–7.30 (m, 2H), 6.00–
White solid; mp 89–90 ꢂC; IR (KBr) 2234 cmꢁ1 1H NMR
;
5.91 (m, 1H), 5.17–5.11 (m, 2H), 3.62 (d, J¼6.7 Hz, 2H); 13C NMR
(500 MHz, CDCl3)
J¼8.2 Hz, 1H), 3.06 (m, 1H), 1.92–1.80 (m, 5H), 1.55–1.41 (m, 4H),
1.31–1.24 (m, 1H); 13C NMR (125 MHz, CDCl3)
156.5, 136.2, 135.9,
d
7.90 (s, 1H), 7.80 (d, J¼8.2 Hz, 1H), 7.51 (d,
(125 MHz, CDCl3)
d 143.8, 134.9, 132.9, 132.8, 129.7, 126.8, 117.9,
117.4, 112.5, 38.5; HRMS (FAB) calcd for (MþH)þ C10H10N: 144.0813,
d
found: 144.0854.
127.8, 116.9, 116.0, 110.1, 43.1, 33.3, 26.3, 25.7; HRMS (FAB) calcd for
(MþH)þ C14H15N2: 211.1236, found: 211.1226.
4.3.10. 2-Benzyl-1-cyanobenzene 5e
Colorless oil; IR (neat) 2224 cmꢁ1
;
1H NMR (500 MHz, CDCl3)
4.4. General procedure for the photoreaction of
d
7.64 (d, J¼7.6 Hz, 1H), 7.51–7.48 (m, 1H), 7.34–7.23 (m, 7H), 4.21 (s,
dicyanobenzenes 1, 4, and 7 with 2 in the presence of Phen
2H); 13C NMR (125 MHz, CDCl3)
d
145.0, 138.8, 132.9, 132.8, 130.1,
129.0, 128.7, 126.8, 126.7, 118.2, 112.6, 40.2; HRMS (FAB) calcd for
An aqueous acetonitrile solution (CH3CN/H2O¼9:1, 120 ml)
(MþH)þ C14H12N: 194.0970, found: 194.0949.
containing dicyanobenzene 1, 4, and 7 (1.2 mmol), sodium

268
T. Itou et al. / Tetrahedron 65 (2009) 263–269
carboxylate 2 (3.6 mmol), and phenanthrene (1.8 mmol) was irra-
diated with a 100-W high-pressure mercury lamp through a Pyrex
filter in an argon atmosphere for 6 h at room temperature. The
solution was filtered and evaporated. Then, the residue was dis-
solved in EtOAc, washed with water, dried over Na2SO4, and con-
centrated under reduced pressure to afford the substituted
products 10 and 11. These products were isolated by silica gel col-
umn chromatography using hexane and EtOAc as eluents and then
by preparative HPLC using a GPC column.
29.3, 29.2, 26.1; HRMS (FAB) calcd for (MþH)þ C18H28NO: 274.2172,
found: 274.2154.
4.4.9. 4-(10-Methoxydecyl)-1,2-dicyanobenzene 6i
White solid; mp 47–48 ꢂC; IR (KBr) 2234 cmꢁ1
;
1H NMR
(500 MHz, CDCl3)
d
7.72 (d, J¼8.2 Hz, 1H), 7.61 (s, 1H), 7.53 (d,
J¼8.2 Hz, 1H), 3.36 (t, J¼6.7 Hz, 2H), 3.33 (s, 3H), 2.71 (t, J¼7.6 Hz,
2H), 1.62–1.50 (m, 4H), 1.30–1.27 (m, 12H); 13C NMR (125 MHz,
CDCl3) d 149.5, 133.5, 133.4, 133.2, 115.5, 113.0, 72.9, 58.5, 35.7, 30.6,
29.6, 29.4, 29.5, 29.3, 29.2, 29.0, 26.1; HRMS (FAB) calcd for (MþH)þ
4.4.1. 9,10-Dihydro-9-cyanophenanthrene 1027
C19H27N2O: 299.2125, found: 299.2131.
White solid; mp 84–85 ꢂC; IR (KBr) 2237 cmꢁ1
;
1H NMR
(500 MHz, CDCl3)
d
7.80 (d, J¼7.6 Hz, 1H), 7.78 (d, J¼7.6 Hz, 1H), 7.57
4.4.10. 3-(10-Methoxydecyl)-1-cyanobenzene 8i
(d, J¼7.6 Hz, 1H), 7.47–7.28 (m, 5H), 4.10 (t, J¼7.8 Hz, 1H), 3.22 (d,
Colorless oil; IR (neat) 2227 cmꢁ1 1H NMR (500 MHz, CDCl3)
;
J¼7.8 Hz, 2H); 13C NMR (125 MHz, CDCl3)
d
133.6,133.2,132.7,129.8,
d
7.49–7.44 (m, 2H), 7.41–7.35 (m, 2H), 3.36 (t, J¼6.7 Hz, 2H), 3.33 (s,
129.2, 128.4, 128.3, 128.2, 128.2, 127.0, 124.5, 124.1, 119.9, 32.9, 31.2;
3H), 2.64 (t, J¼7.6 Hz, 2H), 1.61–1.53 (m, 4H),1.30–1.27 (m, 12H); 13C
MS m/z 205 (Mþ).
NMR (125 MHz, CDCl3) d 144.2, 133.0, 131.9, 129.4, 128.9, 119.1,
112.2, 72.9, 58.5, 35.5, 31.0, 29.6, 29.5, 29.4, 29.4, 29.3, 29.0, 26.1;
HRMS (FAB) calcd for (MþH)þ C18H28NO: 274.2172, found:
274.2171.
4.4.2. 9-Cyanophenanthrene 1128
White solid; mp 108–109 ꢂC; IR (KBr) 2222 cmꢁ1 1H NMR
;
(500 MHz, CDCl3)
d 8.74–8.70 (m, 2H), 8.32–8.30 (m, 1H), 8.27 (s,
1H), 7.96 (d, J¼10.1 Hz, 1H), 7.83–7.71 (m, 3H), 7.71–7.67 (m, 1H);
4.4.11. 4-(10-Methoxydecyl)-1,3-dicyanobenzene 9i
MS m/z 203 (Mþ).
White solid; mp 70–71 ꢂC; IR (KBr) 2235 cmꢁ1
;
1H NMR
(500 MHz, CDCl3)
d
7.90 (s, 1H), 7.78 (d, J¼8.2 Hz, 1H), 7.51 (d,
4.4.3. 4-Methyl-1-cyanobenzene 3f24
J¼8.2 Hz, 1H), 3.36 (t, J¼6.7 Hz, 2H), 3.33 (s, 3H), 2.82 (t, J¼7.6 Hz,
Colorless oil; IR (neat) 2273 cmꢁ1
;
1H NMR (500 MHz, CDCl3)
2H), 1.69–1.53 (m, 4H), 1.36–1.28 (m, 12H); 13C NMR (125 MHz,
d
7.54 (d, J¼8.2 Hz, 2H), 7.27 (d, J¼8.2 Hz, 2H), 2.42 (s, 3H); 13C NMR
CDCl3) d 152.1, 136.1, 135.6, 130.6, 116.9, 116.0, 111.0, 72.9, 58.5, 34.9,
(500 MHz, CDCl3)
(Mþ).
d
143.6, 132.0, 129.8, 119.1, 109.4, 21.8; MS m/z 117
30.5, 29.7, 29.5, 29.4, 29.3, 29.2, 29.1, 26.1; HRMS (FAB) calcd for
(MþH)þ C19H27N2O: 299.2125, found: 299.2100.
4.4.4. 4-(10-Methoxydecyl)-1-cyanobenzene 3i
Acknowledgements
White solid; mp 44–45 ꢂC; IR (KBr) 2227 cmꢁ1
;
1H NMR
(500 MHz, CDCl3)
(t, J¼6.6 Hz, 2H), 3.33 (s, 3H), 2.65 (t, J¼7.6 Hz, 2H),1.60–1.52 (m, 4H),
1.29–1.27 (m, 12H); 13C NMR (125 MHz, CDCl3)
148.9, 132.0, 129.1,
d
7.56 (d, J¼8.2 Hz, 2H), 7.28 (d, J¼8.2 Hz, 2H), 3.36
We thank Kazuyuki Kamiya and Tomoyuki Mizunashi, Univer-
sity of Fukui, Graduate School of Engineering, for their assistance
with HRMS measurement.
d
119.1, 100.5, 72.9, 58.5þ, 36.1, 30.9, 29.6, 29.5, 29.4, 29.3, 29.1; HRMS
(FAB) calcd for (MþH) C18H28NO: 274.2172, found: 274.2163.
References and notes
4.4.5. 4-(2-Butylheptyl)-1-cyanobenzene 3j
1. (a) Abdoh, M. M. M.; Shivaprakash, S. N. C.; Shashidhara Prasad, J. J. Chem. Phys.
1982, 77, 2570–2576; (b) Ichimura, H.; Shirakawa, T.; Tokuda, T.; Seimiya, T. Bull.
Chem. Soc. Jpn. 1983, 56, 2238–2240; (c) Osman, M. A.; Schad, Hp.; Zeller, H. R. J.
Chem. Phys. 1983, 78, 906–914; (d) Schad, Hp.; Osman, M. A. J. Chem. Phys. 1983,
79, 5710–5717.
2. (a) Larock, R. C. Comprehensive Organic Transformations; VCH: New York, NY,
1989; 819; (b) Grundmann, C. In Houben-Weyl: Methoden der organischen
Chemie, 4th ed.; Falbe, J., Ed.; Georg Thieme: Stuttgart, 1985; Vol. E5, p 1313; (c)
Zienkiewicz, J.; Fryszkowska, A.; Zienkiewicz, K.; Guo, F.; Kaszynski, P.; Ja-
nuszko, A.; Jones, D. J. Org. Chem. 2007, 72, 3510–3520.
Colorless oil; IR (neat) 2227 cmꢁ1 1H NMR (500 MHz, CDCl3)
;
d
7.58 (d, J¼8.2 Hz, 2H), 7.23 (d, J¼8.2 Hz, 2H), 2.56–2.50 (m, 1H),
1.67–1.58 (m, 2H), 1.56–1.47 (m, 2H), 1.29–0.99 (m, 12H), 0.85–0.80
(m, 6H); 13C NMR (125 MHz, CDCl3)
152.3, 132.1, 128.4, 119.2,
d
109.5, 46.3, 36.6, 36.3, 31.6, þ29.7, 29.2, 27.4, 22.6, 22.5, 14.0, 13.9;
HRMS (FAB) calcd for (MþH) C18H28N: 258.2271, found: 258.2246.
3. (a) Takagi, K.; Okamoto, T.; Sakakibara, Y.; Oka, S. Chem. Lett. 1973, 471–474; (b)
Anderson, B. A.; Bell, E. C.; Ginah, F. O.; Harn, N. K.; Pagh, L. M.; Wepsiec, J. P. J.
Org. Chem. 1998, 63, 8224–8228; (c) Schareina, T.; Zapf, A.; Beller, M. Chem.
Commun. 2004, 1388–1389; (d) Schareina, T.; Zapf, A.; Ma¨gerlein, W.; Mu¨ ller,
N.; Beller, M. Tetrahedron Lett. 2007, 48, 1087–1090.
4. (a) Ellis, G. P.; Romney-Alexander, T. M. Chem. Rev. 1987, 87, 779–794; (b) Zanon,
J.; Klapars, A.; Buchwald, S. L. J. Am. Chem. Soc. 2003, 125, 2890–2891; (c)
Schareina, T.; Zapf, A.; Beller, M. Tetrahedron Lett. 2005, 46, 2585–2588.
5. Tan, C.; Zheng, X.; Ma, Z.; Gu, Y. Synth. Commun. 1999, 29, 123–127.
6. (a) Borg, R. M.; Arnold, D. R.; Cameron, T. S. Can. J. Chem. 1984, 62, 1785–1802;
(b) Arnold, D. R.; Du, X. J. Am. Chem. Soc. 1989, 111, 7666–7667; (c) Torriani, R.;
Mella, M.; Fasani, E.; Albini, A. Tetrahedron 1997, 53, 2573–2580; (d) Mangion,
D.; Arnold, D. R. Acc. Chem. Res. 2002, 35, 297–304.
7. (a) Mizuno, K.; Ikeda, M.; Otsuji, Y. Tetrahedron Lett. 1985, 26, 461–466; (b)
Mizuno, K.; Nakanishi, K.; Otsuji, Y. Chem. Lett. 1988, 1833–1836; (c) Nakanishi,
K.; Mizuno, K.; Otsuji, Y. Bull. Chem. Soc. Jpn. 1993, 66, 2371–2379.
8. (a) Kyushin, S.; Masuda, Y.; Matsushita, K.; Nakadaira, Y.; Ohashi, M. Tetrahedron
Lett. 1990, 31, 6395–6398; (b) Kako, M.; Nakadaira, Y. Bull. Chem. Soc. Jpn. 2000,
73, 2403–2422.
4.4.6. 10-Methoxydecane 12i
Colorless oil; IR (neat) 2933, 2853 cmꢁ1 1H NMR (500 MHz,
;
CDCl3)
d
3.36 (t, J¼6.7 Hz, 2H), 3.33 (s, 3H), 1.62–1.53 (m, 4H), 1.30–
1.20 (m, 14H), 0.88 (t, J¼7.0 Hz, 3H); 13C NMR (125 MHz, CDCl3)
d
73.0, 58.5, 31.9, 29.7, 29.6, 29.6, 29.5, 29.3, 26.6, 22.6, 14.1; MS m/z
172 (Mþ).
4.4.7. Deuterated 10-methoxydecane
Colorless oil; IR (neat) 2928, 2850, 1110 cmꢁ1
;
1H NMR
(500 MHz, CDCl3)
d
3.36 (t, J¼6.7 Hz, 2H), 3.33 (s, 3H), 1.62–1.53 (m,
4H), 1.30–1.20 (m, 14H), 0.88 (t, J¼7.0 Hz, 2H); 13C NMR (125 MHz,
CDCl3)
d 73.0, 58.5, 31.9,29.7, 29.6, 29.6, 29.5, 29.3, 26.6, 22.6, 14.1;
MS m/z 173 (Mþ).
4.4.8. 2-(10-Methoxydecyl)-1-cyanobenzene 5i
9. (a) Ohashi, M.; Miyake, K. Chem. Lett. 1977, 615–616; (b) Ohashi, M.; Miyake, K.;
Tsujimoto, K. Bull. Chem. Soc. Jpn. 1980, 53, 1683–1688.
Colorless oil; IR (neat) 2224 cmꢁ1 1H NMR (500 MHz, CDCl3)
;
10. (a) Pac, C.; Nakasone, A.; Sakurai, H. J. Am. Chem. Soc. 1977, 99, 5806–5808; (b)
Majima, T.; Pac, C.; Nakasone, A.; Sakurai, H. J. Chem. Soc., Chem. Commun. 1978,
490–491; (c) Majima, T.; Pac, C.; Sakurai, H. J. Am. Chem. Soc. 1980, 102, 5265–
5273; (d) Majima, T.; Pac, C.; Nakasone, A.; Sakurai, H. J. Am. Chem. Soc. 1981,
103, 4499–4508.
d
7.60 (d, J¼7.6 Hz, 1H), 7.53–7.48 (m, 1H), 7.32–7.25 (m, 2H), 3.36 (t,
J¼6.7 Hz, 2H), 3.33 (s, 3H), 2.82 (t, J¼7.6 Hz, 2H), 1.69–1.53 (m, 4H),
1.36–1.28 (m, 12H); 13C NMR (125 MHz, CDCl3)
146.8, 132.7, 132.6,
129.4, 126.2, 118.2, 112.3, 72.9, 58.5, 34.6, 30.9, 29.6, 29.5, 29.4, 29.4,
d

T. Itou et al. / Tetrahedron 65 (2009) 263–269
269
11. Yoshimi, Y.; Itou, T.; Hatanaka, M. Chem. Commun. 2007, 5244–5246.
12. Tsujimoto, K.; Nakao, N.; Ohashi, K. J. Chem. Soc. Chem. Commun. 1992, 366–367.
13. When dry acetonitrile was used as a solvent, the carboxylate ions did not
dissolve in the solution.
cyanoacetate proceeded efficiently both in the absence and in the presence of
Phen; however, the substituted product 3 was not obtained, since the gener-
ated radicals were readily reduced via the BET to yield the corresponding
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