Copper-catalyzed one-pot synthesis of unsymmetrical arylurea derivatives via tandem reaction of diaryliodonium salts with N -arylcyanamide

Article abstract of DOI:10.1021/jo501334u

An efficient "one-pot" approach to multiple substituted ureas from N-arylcyanamide and diaryliodonium salts has been presented. The two-step procedure involved the weak base-promoted chemoselective arylation of secondary amines with diaryliodonium and Cu-catalyzed nucleophilic addition of N-arylcyanamide with second diaryliodonium. The diverse unsymmetrical arylureas were obtained in up to 91% yield for 29 examples.

Full text of DOI:10.1021/jo501334u

Article
pubs.acs.org/joc
Copper-Catalyzed One-Pot Synthesis of Unsymmetrical Arylurea
Derivatives via Tandem Reaction of Diaryliodonium Salts with
N‑Arylcyanamide
Pengfei Li, Guolin Cheng,* Hong Zhang, Xianxiang Xu, Jingyuan Gao, and Xiuling Cui*
Key Laboratory of Xiamen Marine and Gene Drugs, Institutes of Molecular Medicine and School of Biomedical Sciences, Huaqiao
University & Engineering Research Center of Molecular Medicine, Ministry of Education, Xiamen 361021, China
S
* Supporting Information
ABSTRACT: An efficient “one-pot” approach to multiple
substituted ureas from N-arylcyanamide and diaryliodonium
salts has been presented. The two-step procedure involved the
weak base-promoted chemoselective arylation of secondary
amines with diaryliodonium and Cu-catalyzed nucleophilic
addition of N-arylcyanamide with second diaryliodonium. The
diverse unsymmetrical arylureas were obtained in up to 91% yield for 29 examples.
Scheme 1
INTRODUCTION
■
Arylureas are present in natural products and bioactive
compounds1 and have found myriad applications in dyes,
pharmaceutics, and industrial chemistry.2 In particular, some
arylureas have been shown a marked inhibiting effect on HIV
protease enzyme.3 Therefore, numerous methods have been
developed for building such a structure. Conventionally,
phosgene and its derivatives have been used as starting
materials.4 However, the preparation and use of phosgenes
usually generates excessive toxicological and environmental
waste. The transition-metal-catalyzed reaction of amines with
CO as the carbonyl source in the presence of an oxidant have
shown an alternative procedure to the ureas.5 This procedure is
limited to the primary arylamines since secondary amines
produced formamides.6 N-Aryl- and N-heteroarylureas were
usually prepared by the reaction of arylamines with
isocyanates.7 The instability of the isocyanates led to the
desired products in low yields.8 From the point of green
chemistry and broad generality, the development of an efficient
and mild protocol to multiply aryl-substituted ureas from the
easily handled starting materials is highly desired.
screened at room temperature in the presence of K2CO3. When
toluene was used as the solvent, the desired product was
obtained in 94% yield (Table 1, entry 5). Other solvents (e.g.,
DMF, DMSO, and 1,4-dioxane) afforded lower yields (Table 1,
entries 2−4). We then investigated the influence of the bases.
When other bases, such as Na2CO3, Li2CO3, t-BuOLi, and
Cs2CO3, were used in place of K2CO3, Cs2CO3 could afford the
desired product in 97% yield (Table 1, entry 9). When the
amount of base was decreased to 2 and 1.5 equiv, 3a was
provided in 95% and 89% yields, respectively (Table 1, entries
10 and 11). Elevating the reaction temperature did not
significantly improve this transformation (Table 1, entry 12).
Compound 3a was not obtained in the air (Table 1, entry 13)
since NH in N-(4-methoxyphenyl)cyanamide might be
oxidized by O2 in the air. The reaction could not proceed
well in the absence of base (Table 1, entry 14). The optimized
reaction conditions were identified as follows: 1a (0.5 mmol),
2a (0.5 mmol), Cs2CO3 (2 equiv), toluene (1 mL), room
temperature, N2 atmosphere.
Diaryliodonium salts have recently gained considerable
attention as mild, selective, and environmentally benign regents
in organic synthesis.9,10 Herein we envisioned that triaryl-
substituted ureas could be prepared from N-arylcyanamides11
with two different diaryliodonium salts in a “one-pot” manner
(Scheme 1).
Next, the condensation of 2a with isolated 3a was chosen as a
model reaction to screen the second reaction parameters
(shown in Table 2). When DMSO was used as solvent with
Cu(OTf)2 as a catalyst and H2O as additive, the product 4a was
obtained in 24% yield (Table 2, entry 1). Other polar solvents,
such as DMF, 1,4-dioxane, and MeCN, were also ineffective
RESULTS AND DISCUSSION
■
At the outset of the study, the reaction of 1a and 2a afforded N-
(4-methoxyphenyl)cyanamide 3a in 93% yield in the presence
of 3 equiv of K2CO3 in DCE at room temperature under N2 for
5 h (Table 1, entry 1). Inspired by this result, we next screened
the solvents, base, temperature, and loading of the reagents to
optimize the reaction conditions. First, various solvents were
Received: June 19, 2014
Published: August 10, 2014
© 2014 American Chemical Society
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(Table 2, entries 2−4). When this reaction was conducted in
DCE and toluene, the desired product was obtained in 76% and
77% yields, respectively (Table 2, entries 5 and 6). Compared
to toluene, the waste from halide compounds was difficult to
handle. Moreover, the arylation of secondary amines with
diaryliodonium salt could proceed well in toluene. Therefore,
toluene was chosen as solvent for the second step. Then various
copper salts were examined in toluene at 60 °C. No desired
product was obtained in the presence of Cu(OAc)2 and CuBr2
(Table 2, entries 7 and 8). When CuCN, Cu(TFA)2, CuBr,
CuI, and CuOTf were used as the catalysts, the reaction gave 4a
in 37%, 43%, 55%, 72%, and 73% yields, respectively (Table 2,
entries 9−13). Cu(OTf)2 provided the desired product 4a in
77% yield (Table 2, entry 6). Increasing the loading of 2a from
0.5 to 0.6 mmol resulted in a higher yield (90%) (Table 2, entry
14). The yield was not improved by increasing the loading of
2a from 0.6 to 0.7 mmol (Table 2, entry 15), and the reaction
under N2 atmosphere gave lower yield (Table 2, entry 16).
Different temperatures were also examined (Table 2, entries 17
and 18). The best result was obtained at 60 °C. The yield of
product decreased when the loading of Cu(OTf)2 was reduced
(Table 2, entry 19). No reaction was observed in the absence of
Cu(OTf)2 (Table 2, entry 20), even when the reaction was
carried out at 120 °C (Table 2, entry 21). Considering that the
reaction was completely inhibited by base (Table 2, entry 22),
and not obviously affected by acid (Table 2, entry 23), a “one-
pot” approach to arylureas 4 directed from N-arylcyanamide 1
without isolating the intermediates 3 was carried out. When the
reaction of 1 with 2 was finished completely, AcOH was added
dropwise to neutralize the base and provided enough H2O to
the reaction. Then, the resulting reaction mixture was treated
with Cu(OTf)2 and 1.2 equiv of a second diaryliodonium salt 2
and gave 4a in 89% yield.
Table 1. Optimizing the Reaction Conditions for Arylation
of Secondary Amines
a
entry
solvent
DCE
base
time (h)
yield (%)
1
2
3
4
5
6
7
8
9
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
Na2CO3
Li2CO3
t-BuOLi
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
5
5
93
DMF
89
DMSO
1,4-dioxane
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
5
78
5
85
5
94
5
89
5
trace
62
5
5
97
b
10
5
95
c
11
5
89
d
12
4
98
e
13
>24
>24
oxidation
NR
14
a
Reaction conditions: 1a (0.5 mmol), 2a (0.5 mmol), base (3 equiv),
solvent (1 mL) under N2 at room temperature. NR = no reaction.
b
c
d
e
Cs2CO3 (2 equiv). Cs2CO3 (1.5 equiv). 60 °C. Under air.
Table 2. Optimizing the Reaction Conditions for Arylation
a
of Nitrile
The generality and scope of N-arylcyanamide derivatives 1
were explored under the optimal reaction conditions as shown
in Table 3. The electronic effects of the substituent at the N-
arylcyanamide did not affect the reaction significantly. N-
Arylcyanamide with both electron-donating groups, such as
−OMe, −Me, −i-Pr, and electron-withdrawing groups, such as
−F, −Cl, −Br, and −I, at the para position of N-benzene
performed well, giving the desired products 4a−h in 79−86%
yields. The slight influence of the steric hindrance on this
transformation was observed. For instance, N-(4-
chlorophenyl)cyanamide, N-(3-chlorophenyl)cyanamide, and
N-(2-chlorophenyl)cyanamide afforded the corresponding
products in 85%, 79%, and 70% yields, respectively (4f, 4j,
4k). N-(2-Methoxyphenyl)cyanamide gave a lower yield than
N-(4-methoxyphenyl)cyanamide (4i vs 4a), and polysubsti-
tuted N-arylcyanamide derivatives containing electron-donating
or electron-withdrawing groups in the aryl ring provided the
corresponding arylureas in good yields (Table 3, 4l−p).
Interestingly, N-(naphthalen-2-yl)cyanamide was also applica-
ble to this reaction system and gave the product 4q in 77%
yield. N-Methylcyanamide was compatible with the reaction
conditions and gave the product in 91% yield (Table 3, 4r).
Next, we explored the generality and scope of diaryliodonium
salts 2.12 As shown in Table 4, we found that the electronic
effect of the substituent on this reaction was also not significant.
The diaryliodonium salts containing electron-withdrawing
groups such as −Br, −I, −CF3, and −NO2 in the para or
meta positions of the aryl moiety were efficiently coupled with
the N-(4-methoxyphenyl)cyanamide, producing the corre-
sponding desired products with 70−88% yields (Table 4,
entry
catalyst
solvent
DMSO
time (h)
yield (%)
1
Cu(OTf)2
Cu(OTf)2
Cu(OTf)2
Cu(OTf)2
Cu(OTf)2
Cu(OTf)2
Cu(OAc)2
CuBr2
22
23
24
27
2
DMF
3
MeCN
1,4-dioxane
DCE
18
19
4
>24
25
15
5
76
6
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
20
77
7
>24
>24
>24
>24
23
NR
NR
37
8
9
CuCN
10
11
12
13
Cu(TFA)2
CuBr
43
55
CuI
22
72
CuOTf
22
73
b
14
Cu(OTf)2
Cu(OTf)2
Cu(OTf)2
Cu(OTf)2
Cu(OTf)2
Cu(OTf)2
19
90
c
15
19
86
bd
,
16
17
18
19
20
21
22
23
22
68
be
,
17
49
bf
,
20
77
bg
,
20
83
b
h
>48
>48
>48
19
NR
NR
NR
89
bi
,
Cu(OTf)2
Cu(OTf)2
bj
,
a
Reaction conditions: 3a (0.5 mmol), 2a (0.5 mmol), H2O (1 equiv),
Cu catalyst (0.1 mmol), toluene (1 mL), under air, NR = no reaction.
2a (0.6 mmol). 2a (0.7 mmol). Under N2. 90 °C. 50 °C.
Cu(OTf)2 (0.05 mmol). 120 °C. 1 equiv of Cs2CO3. 1 equiv of
AcOH.
b
c
d
e
f
g
h
i
j
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Table 3. Substrate Scope: Variation of the N-
Arylcyanamides
Table 4. Substrate Scope: Variation of the Diaryliodonium
Salts
a
a
a
Reaction conditions: first step, 1 (0.5 mmol), 2a (0.5 mmol), Cs2CO3
(2 equiv) in toluene (1 mL) under N2 at room temperature for 5 h;
second step, AcOH (4 equiv), 30 min; third step, 2a (0.6 mmol),
Cu(OTf)2 (0.2 equiv) at 60 °C for 21 h.
entries 1−5). The diaryliodonium salts with electron-donating
groups provided 4bf in 77% yield (Table 4, entry 6). However,
the steric hindrance of diaryliodonium salts affected this
reaction slightly. Compounds 4bg, 4bh, and 4bi were obtained
in 66%, 53%, and 57% yields, respectively. It was valuable to
note that only one aryl group was transferred preferentially in
case of unsymmetrical iodonium salts, such as 2f, 2h, 2i, and 2j.
A heteroaryl group, such as pyridyl, could be tolerated.
However, the chemoselectivity was poor. Mixtures of 4bj and
4a were obtained and isolated in 51% and 33% yields,
respectively. When unsymmetrical iodonium salt (2h) was
used in the first step, 4bk was obtained in good yield (Table 4,
entry 11).
a
Reaction conditions: first step, 1 (0.5 mmol), 2a (0.5 mmol), Cs2CO3
(2 equiv) in toluene (1 mL) under N2 at room temperature for 5 h;
second step, AcOH (4 equiv), 30 min; thrid step, 2a−k (0.6 mmol),
Cu(OTf)2 (0.2 equiv) at 60 °C for 21 h. First step, 2h alternative 2a.
b
addition to the Cu(I)OTf species by the diaryliodonium salt
gave a Ph−Cu(III) species, which transferred the aryl group to
the cyano of the N,N-diphenylcyanamide to produce
intermediate A, which generated the N,N,N′-triphenylurea 4
as the desired product by hydrolysis. In this process, the
Cu(I)OTf was regenerated for the next cycle.
Finally, a gram experiment with 14 mmol (2.07 g) of 1a, 30.8
mmol (13.12 g) of 2a, 28 mmol (9.12 g) of Cs2CO3, 56 mmol
(3.36 g) of AcOH, and toluene (40 mL) was employed.
Compound 4a was obtained in 69% yield. Iodobenzene (yellow
oil) was obtained in 77% yield (4.84 g).
According to the literature and the results obtained
above,10,13 a plausible reaction mechanism was proposed and
is shown in Scheme 2. Initially, Cs2CO3-promoted N-arylation
of N-phenylcyanamide with 1 equiv of diaryliodonium salts
gave the intermediate 3, and Cu(OTf)2 was converted into
Cu(I)OTf by either a reduction or disproportion. Oxidative
CONCLUSION
■
In summary, we have presented an efficient, operationally
simple and chemoselective protocol to synthesize triarylurea
derivatives using N-arylcyanamide and two different diary-
liodonium salts as starting materials in a “one-pot” process. In
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purified by chromatography (silica gel, eluent: EtOAc/PE = 1/15) to
give 4.
Scheme 2. Proposed Mechanism
1-(1-Methoxyphenyl)-1,3-diphenylurea (4a): 130 mg (83%); white
solid; mp 111−112 °C; 1H NMR (400 MHz, CDCl3) δ 7.37−7.32 (m,
6H), 7.27 (ddd, J = 16.9, 8.2, 5.3 Hz, 5H), 7.03 (d, J = 7.3 Hz, 1H),
6.96−6.93 (m, 2H), 6.45 (s, 1H), 3.83 (s, 3H); 13C{1H} NMR (100
MHz, CDCl3) δ 158.5, 153.7, 142.7, 138.6, 134.8, 129.3, 126.7, 126.0,
123.2, 119.3, 115.1, 77.3, 77.0, 76.7, 55.5; HRMS (ESI) m/z calcd for
C20H18N2O2 [M + H]+ 319.1447, found 319.1443; IR (KBr) cm−1
2958, 1684, 1597, 1507, 1440, 1315, 1242, 1031, 753, 695.
1,3-Diphenyl-1-(p-tolyl)urea (4b): 126 mg (83%); white solid; mp
1
131−132 °C; H NMR (400 MHz, CDCl3) δ 7.38−7.32 (m, 6H),
7.28−7.22 (m, 7H), 7.04−7.00 (m, 1H), 6.47 (s, 1H), 2.38 (s, 3H);
13C{1H} NMR (100 MHz, CDCl3) δ 153.6, 142.6, 139.6, 138.5, 137.0,
130.4, 129.3, 128.8, 127.7, 127.0, 126.2, 123.2, 119.3, 77.3, 77.0, 76.7,
21.0; HRMS (ESI) m/z calcd for C20H18N2O [M + H]+ 303.1497,
found 303.1495; IR (KBr) cm−1 1681, 1598, 1523, 1493, 1439, 1318,
1297, 1232, 755, 695.
1-(4-Isopropylphenyl)-1,3-diphenylurea (4c): 132 mg (79%);
yellow oil; 1H NMR (400 MHz, CDCl3) δ 7.39−7.32 (m, 6H),
7.28−7.23 (m, 7H), 7.02 (s, 1H), 6.46 (s, 1H), 2.93 (s, 1H), 1.27 (d, J
= 6.9 Hz, 6H); 13C{1H} NMR (100 MHz, CDCl3) δ 153.6, 147.7,
142.5, 139.7, 138.6, 129.4, 128.8, 127.6, 127.2, 126.3, 123.2, 119.3,
77.3, 77.0, 76.7, 33.7, 23.9; HRMS (ESI): m/z calcd for C22H22N2O
[M + H]+ 331.1810, found 331.1809; IR (KBr) cm−1 2960, 1687,
1597, 1522, 1440, 1315, 1234, 750, 694.
comparison to the methods reported in the literature using
isocyanates and phosgene as starting reagents, diaryliodonium
salts are more stable, easy handle, and beneficial to the
environment, which made this protocol more attractive and
highly practical for the synthesis of the fundamentally
important arylurea derivatives.
1,1,3-Triphenylurea (4d):14 98 mg (85%); white solid; mp133−136
1
°C; H NMR (400 MHz, CDCl3) δ 7.42−7.38 (m, 5H), 7.35 (d, J =
1.5 Hz, 3H), 7.32 (d, J = 1.2 Hz, 2H), 7.28−7.26 (m, 5H), 6.44 (s,
1H); 13C{1H} NMR (100 MHz, CDCl3) δ 153.5, 142.3, 138.4, 129.6,
128.9, 127.5, 126.6, 123.3, 119.3, 77.3, 77.0, 76.7; IR (KBr) cm−1 2922,
1678, 1594, 1516, 1489, 1438, 1326, 1229, 1025, 758, 703, 567.
1-(4-Fluorophenyl)-1,3-diphenylurea (4e): 132 mg (84%); white
EXPERIMENTAL SECTION
General Methods. All commercial materials and solvents were
used directly without further purification. Melting points were
■
1
1
solid; mp 112−114 °C; H NMR (400 MHz, CDCl3) δ 7.42 (dd, J =
determined on a melting point apparatus and were uncorrected. H
and 13C{1H} NMR spectra were measured on a 400 MHz
spectrometer (1H 400 MHz, 13C 100 MHz) using CDCl3 as the
solvent with tetramethylsilane (TMS) as the internal standard at room
temperature. HRMS ESI spectra were obtained on Q-TOF
spectrometer.
10.5, 5.0 Hz, 2H), 7.35−7.29 (m, 7H), 7.25 (t, J = 4.2 Hz, 2H), 7.09−
7.01 (m, 3H), 6.42 (s, 1H); 13C{1H} NMR (100 MHz, CDCl3) δ
162.1, 159.6, 153.5, 142.1, 138.3 (d, J = 8.9 Hz), 129.9, 129.1, 129.0,
128.9, 127.6, 127.1, 123.4, 119.4, 116.4, 116.2, 77.3, 77.0, 76.7; HRMS
(ESI) m/z calcd for C19H15FN2O [M + H]+ 307.1247, found
307.1247; IR (KBr) cm−1 3245, 1661, 1596, 1528, 1503, 1440, 1324,
754, 693.
Preparation of N-Arylcyanamide 1. Aniline (10 mmol, 46.6 mg/
mL, 1 equiv) and NaHCO3 (35 mmol, 147.02 mg/mL, 3.5 equiv)
were added in 20 mL of toluene with cyanogen bromide (20 mmol,
105.92 mg/mL, 2 equiv) under N2. The mixture was stirred for 3 h at
room temperature, quenched with water, and extracted with EtOAc (3
× 40 mL). The organic layers were combined, washed with H2O and
brine, dried by MgSO4, and concentrated under reduced pressure to
give a residue, which was purified by flash chromatography (SiO2,
eluent: DCM/heptane = 1/1).
Preparation of Diaryliodonium Salts 2. 3-Chloroperoxybenzoic
acid (65%, 660 mg, 2.6 mmol) and aryl iodide were dissolved in
CH2Cl2 (10 mL) in a sealed tube. The arene (2.6 mmol) was added.
The solution was cooled to 0 °C, and then TfOH was added dropwise.
The reaction was stirred at the indicated temperature for 0.2−22 h.
The solvent was concentrated under vacuum. Et2O (10 mL) was
added, and the mixture was stirred at room temperature for 10 min to
precipitate out an off-white solid. To ensure complete precipitation,
the flask was stored in the freezer for 30 min before the solid was
filtered off, washed with Et2O, and dried under vacuum to give
diaryliodonium salts 2.
Preparation of N,N,N′-Triphenylurea 4. A mixture of diary-
liodonium salts 2 (0.5 mmol, 213 mg/mL, 1 equiv), N-phenyl-
cyanamide 1 (0.5 mmol, 74 mg/mL, 1 equiv), and Cs2CO3 (1 mmol,
325.8 mg/mL, 2 equiv) in toluene (1 mL) were stirred at room
temperature in a glass flask under N2 atmosphere for 5 h. Then AcOH
(2 mmol, 120.1 mg/mL, 4 equiv) was added dropwise and the miture
stirred for 30 min. Cs2CO3 was neutralized. The second diary-
liodonium salts 2 (0.6 mmol, 255.6 mg/mL, 1.2 equiv) and Cu(OTf)2
(0.1 mmol, 36.2 mg/mL, 0.2 equiv) were added. The resulting mixture
was stirred at 60 °C for 21 h. After the reaction was complete
(monitored by TLC), the solvent was evaporated and the residue was
1-(4-Chlorophenyl)-1,3-diphenylurea (4f): 137 mg (85%); white
solid; mp 145−146 °C; 1H NMR (400 MHz, CDCl3) δ 7.49−7.42 (m,
4H), 7.34−7.31 (m, 4H), 7.29−7.24 (m, 3H), 7.20−7.16 (m, 2H),
7.04 (dd, J = 7.7, 6.8 Hz, 1H), 6.41 (s, 1H); 13C{1H} NMR (100 MHz,
CDCl3) δ 153.3, 141.8, 141.1, 138.2, 131.6, 130.1, 129.4, 128.9, 128.0,
127.5, 123.5, 119.5, 77.3, 77.0, 76.7; HRMS (ESI) m/z calcd for
C19H15ClN2O [M + H]+ 323.0951, found 323.0948; IR (KBr) cm−1
3242, 1663, 1596, 1532, 1489, 1440, 1325, 691, 672, 653.
1-(4-Bromophenyl)-1,3-diphenylurea (4g): 157 mg (86%); yellow
solid; mp 146−148 °C; 1H NMR (400 MHz, CDCl3) δ 7.49−7.42 (m,
4H), 7.34−7.31 (m, 4H), 7.29−7.24 (m, 3H), 7.20−7.16 (m, 2H),
7.04 (dd, J = 7.7, 6.8 Hz, 1H), 6.41 (s, 1H); 13C{1H} NMR (100 MHz,
CDCl3) δ 153.2, 141.7, 138.2, 132.3, 130.1, 128.9, 128.3, 128.0, 127.5,
123.6, 119.4, 77.3, 77.0, 76.7; HRMS (ESI): m/z calcd for
C19H15BrN2O [M + H]+ 367.0446, found 367.0440; IR (KBr) cm−1
3239, 2923, 1663, 1596, 1531, 1487, 1440, 1326, 1277, 1245, 755, 694.
1-(4-Iodophenyl)-1,3-diphenylurea (4h): 172 mg (81%); white
solid; mp 151−153 °C; 1H NMR (400 MHz, CDCl3) δ 7.47−7.42 (m,
2H), 7.36−7.23 (m, 9H), 7.07−7.03 (m, 3H), 6.42 (s, 1H); 13C{1H}
NMR (100 MHz, CDCl3) δ 153.2, 142.5, 141.6, 138.3, 138.2, 130.1,
128.9, 128.5, 128.1, 127.6, 123.6, 119.5, 90.4, 77.3, 77.0, 76.7; HRMS
(ESI) m/z calcd for C19H15IN2O [M + H]+ 415.0307, found 415.0304;
IR (KBr) cm−1 2921, 1662, 1596, 1528, 1485, 1440, 1325, 1247, 756,
693.
1-(2-Methoxyphenyl)-1,3-diphenylurea (4i): 111 mg (68%);
1
yellow oil; H NMR (400 MHz, CDCl3) δ 7.36−7.31 (m, 8H), 7.24
(dd, J = 11.0, 4.9 Hz, 3H), 7.04−6.98 (m, 3H), 6.44 (s, 1H), 3.83 (s,
3H); 13C{1H} NMR (100 MHz, CDCl3) δ 156.1, 153.8, 142.4, 138.8,
130.9, 130.6, 129.6, 129.0, 128.8, 126.5, 125.9, 123.0, 121.5, 119.3,
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112.6, 77.3, 77.0, 76.7, 55.9; HRMS (ESI) m/z calcd for C20H18N2O2
[M + H]+ 319.1447, found 319.1443; IR (KBr) cm−1 2918, 2849,
1686, 1595, 1522, 1497, 1440, 1313, 1275, 1235, 1026, 753, 693.
1-(3-Chlorophenyl)-1,3-diphenylurea (4j): 124 mg (79%); orange
2H), 7.79−7.75 (m, 2H), 7.51−7.48 (m, 2H), 7.42−7.33 (m, 6H),
7.31−7.24 (m, 4H), 7.03 (t, J = 7.3 Hz, 1H), 6.55 (s, 1H);
13C{1H}NMR (100 MHz, CDCl3) δ 153.6, 142.4, 139.8, 138.4, 133.8,
131.8, 129.6, 128.9, 127.9, 127.3, 126.7, 126.3, 125.8, 125.6, 123.3,
119.4, 77.3, 77.0, 76.7; HRMS (ESI) m/z calcd for C23H18N2O [M +
H]+ 339.1497, found 339.1496; IR (KBr) cm−1 3055, 2923, 1663,
1595, 1526, 1495, 1440, 1316, 1240, 752, 694, 670.
1-Methyl-1,3-diphenylurea (4r): 103 mg (91%); white solid; mp
80−81 °C; 1H NMR (400 MHz, CDCl3) δ 7.48 (dd, J = 10.5, 4.8 Hz,
2H), 7.39−7.32 (m, 3H), 7.29−7.21 (m, 4H), 7.00−6.96 (m, 1H),
6.25 (s, 1H), 3.34 (s, 3H); 13C{1H} NMR (100 MHz, CDCl3) δ 154.4,
142.9, 138.8, 130.3, 128.7, 127.8, 127.4, 122.8, 119.2, 77.3, 77.0, 76.7,
37.2; HRMS (ESI): m/z calcd for C14H14N2O [M + H]+ 227.1184,
found 227.1184; IR (KBr) cm−1 3285, 1648, 1594, 1527, 1496, 1444,
1349, 752, 698.
1
solid; mp 123−125 °C; H NMR (400 MHz, CDCl3) δ 7.46 (dt, J =
9.6, 2.1 Hz, 2H), 7.39−7.30 (m, 6H), 7.30−7.24 (m, 3H), 7.19 (dddd,
J = 7.7, 6.7, 1.9, 1.1 Hz, 2H), 7.07−7.02 (m, 1H), 6.42 (s, 1H);
13C{1H} NMR (100 MHz, CDCl3) δ 153.2, 143.8, 141.5, 138.2, 134.7,
130.1, 128.9, 128.2, 127.7, 126.8, 126.0, 124.7, 123.6, 119.5, 77.3, 77.0,
76.7; HRMS (ESI) m/z calcd for C19H15ClN2O [M + H]+ 323.0951,
found 323.0948; IR (KBr) cm−1 3246, 2921, 1664, 1594, 1531, 1442,
1321, 1244, 1092, 1029, 756, 690.
1-(2-Chlorophenyl)-1,3-diphenylurea (4k): 117 mg (70%); yellow
solid; mp 121−123 °C; 1H NMR (400 MHz, CDCl3) δ 7.43−7.41 (m,
1H), 7.39−7.34 (m, 8H), 7.29−7.24 (m, 4H), 7.04 (t, J = 7.4 Hz, 1H),
6.45 (s, 1H); 13C{1H} NMR (100 MHz, CDCl3) δ 152.9, 141.6, 139.5,
138.3, 134.0, 131.2, 131.0, 129.5, 129.2, 128.9, 128.2, 126.6, 123.4,
119.5, 77.3, 77.0, 76.7; HRMS (ESI) m/z calcd for C19H15ClN2O [M
+ H]+ 323.0951, found 323.0949; IR (KBr) cm−1 3248, 1672, 1597,
1531, 1496, 1441, 1326, 1248, 1030, 751, 692.
3-(4-Bromophenyl)-1-(4-methoxyphenyl)-1-phenylurea (4ba):
1
160 mg (82%); white solid; mp 148−149 °C; H NMR (400 MHz,
CDCl3) δ 7.37−7.34 (m, 4H), 7.32−7.28 (m, 3H), 7.26−7.22 (m,
4H), 6.95−6.93 (m, 2H), 6.45 (s, 1H), 3.82 (s, 3H); 13C{1H} NMR
(100 MHz, CDCl3) δ 158.7, 153.5, 142.5, 137.7, 134.5, 131.7, 129.3,
129.3, 126.8, 126.2, 120.8, 115.6, 115.1, 77.3, 77.0, 76.7, 55.5; HRMS
(ESI) m/z calcd for C20H17BrN2O2 [M + H]+ 397.0552, found
397.0546; IR (KBr) cm−1 2962, 2923, 1661, 1588, 1513, 1489, 1393,
1310, 1243, 1098, 1034, 801, 750, 692, 667.
1-(4-Methoxy-2-methylphenyl)-1,3-diphenylurea (4l): 124 mg
1
(74%); yellow oil; H NMR (400 MHz, CDCl3) δ 7.33 (dd, J = 8.6,
1.2 Hz, 2H), 7.30−7.25 (m, 8H), 7.03 (d, J = 7.3 Hz, 1H), 6.87 (t, J =
3.4 Hz, 2H), 6.38 (s, 1H), 3.84 (s, 3H), 2.25 (s, 3H); 13C{1H} NMR
(100 MHz, CDCl3) δ 159.5, 153.6, 142.2, 138.8, 138.6, 132.6, 130.9,
128.9, 128.8, 124.8, 124.7, 123.2, 119.4, 117.0, 113.1, 77.3, 77.0, 76.7,
55.5, 18.2; HRMS (ESI) m/z calcd for C21H20N2O2 [M + H]+
333.1603, found 333.1601; IR (KBr) cm−1 2923, 1686, 1598, 1520,
1497, 1439, 1312, 1294, 1233, 753, 693.
3-(4-Iodophenyl)-1-(4-methoxyphenyl)-1-phenylurea (4bb): 182
mg (82%); yellow solid; mp 138−140 °C; 1H NMR (400 MHz,
CDCl3) δ 7.55−7.52 (m, 2H), 7.35 (d, J = 7.2 Hz, 2H), 7.29 (dt, J =
5.9, 1.8 Hz, 4H), 7.22 (s, 1H), 7.14−7.11 (m, 2H), 6.96−6.92 (m,
2H), 6.42 (s, 1H), 3.83 (s, 3H); 13C{1H} NMR (100 MHz, CDCl3) δ
158.7, 153.4, 138.5, 137.7, 129.4, 129.3, 126.8, 126.3, 121.1, 115.2,
77.3, 77.0, 76.7, 55.5; HRMS (ESI): m/z calcd for C20H17IN2O2 [M +
H]+ 445.0413, found 445.0410; IR (KBr) cm−1 2918, 2849, 1662,
1583, 1509, 1486, 1392, 1312, 1285, 1245, 1035, 793, 752, 691, 669.
1-(4-Methoxyphenyl)-3-(4-nitrophenyl)-1-phenylurea (4bc): 161
1-(3,5-Dimethylphenyl)-1,3-diphenylurea (4m): 117 mg (74%);
1
white solid; mp 102−104 °C; H NMR (400 MHz, CDCl3) δ 7.40−
7.32 (m, 6H), 7.25 (dd, J = 12.9, 4.8 Hz, 3H), 7.02 (t, J = 7.3 Hz, 1H),
6.97 (s, 2H), 6.94 (s, 1H), 6.46 (s, 1H), 2.31 (s, 6H); 13C{1H} NMR
(100 MHz, CDCl3) δ 153.6, 142.6, 141.9, 139.5, 138.6, 129.3, 128.9,
127.1, 126.2, 125.6, 123.1, 119.3, 77.3, 77.0, 76.7, 21.2; HRMS (ESI)
m/z calcd for C21H20N2O [M + H]+ 317.1654, found 317.1654; IR
(KBr) cm−1 3294, 2959, 2922, 1664, 1594, 1523, 1495, 1440, 1316,
1293, 1239, 754, 694.
1
mg (88%); yellow oil; H NMR (400 MHz, CDCl3) δ 7.33 (dd, J =
9.0, 4.4 Hz, 6H), 7.29 (d, J = 2.2 Hz, 1H), 7.25 (dd, J = 10.4, 6.6 Hz,
5H), 6.95−6.92 (m, 2H), 6.44 (s, 1H), 3.82 (s, 3H); 13C{1H} NMR
(100 MHz, CDCl3) δ 158.5, 153.8, 142.8, 136.0, 134.9, 132.7, 129.3,
129.2, 128.8, 126.7, 125.9, 119.4, 115.0, 77.3, 77.0, 76.7, 55.5; HRMS
(ESI) m/z calcd for C20H17N3O4 [M + H]+ 364.1297, found 364.1294;
IR (KBr) cm−1 3041, 2953, 2930, 1634, 1617, 1572, 1473, 1446, 1375,
1340, 1296, 1262, 1227, 1197, 1199, 1029, 795, 772, 715, 690.
3-(4-tert-Butylphenyl)-1-(4-methoxyphenyl)-1-phenylurea (4bd):
146 mg (75%); yellow oil; 1H NMR (400 MHz, CDCl3) δ 7.34(dd, J =
11.2, 2.4 Hz, 7H), 7.29−7.28 (m, 1H), 7.26 (s, 1H), 6.96−6.92 (m,
2H), 6.85 (s, 2H), 5.73 (s, 1H), 3.82 (s, 3H), 1.60 (d, J = 8.1 Hz, 9H);
13C{1H} NMR (100 MHz, CDCl3) δ 158.5, 154.4, 143.2, 139.3, 135.4,
131.9, 129.4, 129.1, 128.8, 126.2, 125.5,115.0, 114.1, 77.3, 77.0, 76.7,
55.5, 33.8, 31.9; HRMS (ESI) m/z calcd for C24H26N2O2 [M + H]+
375.2073, found 375.2072; IR (KBr) cm−1 2959, 2925, 2854, 1685,
1491, 1289, 12471032, 831, 750, 696.
1-(3-Fluoro-4-methylphenyl)-1,3-diphenylurea (4n): 130 mg
1
(80%); yellow solid; mp 97−99 °C; H NMR (400 MHz, CDCl3) δ
7.42 (tt, J = 4.2, 1.9 Hz, 2H), 7.34−7.31 (m, 4H), 7.29−7.24 (m, 3H),
7.17 (t, J = 8.4 Hz, 1H), 7.05−6.98 (m, 3H), 6.43 (s, 1H), 2.26 (d, J =
1.8 Hz, 3H); 13C{1H} NMR (100 MHz, CDCl3) δ 162.4, 160.0, 153.3,
141.9, 138.3, 131.7 (d, J = 6.2 Hz), 129.9, 128.9, 127.7, 127.2, 123.4
(d, J = 17.1 Hz), 122.4, 119.4, 114.1, 113.9, 77.3, 77.0, 76.7, 14.2;
HRMS (ESI) m/z calcd for C20H17FN2O [M + H]+ 321.1403, found
321.1402; IR (KBr) cm−1 2920, 1663, 1596, 1532, 1502, 1441, 1323,
1245, 757, 695.
1-(3-Fluoro-5-methylphenyl)-1,3-diphenylurea (4o): 118 mg
1
(75%); white solid; mp 131−132 °C; H NMR (400 MHz, CDCl3)
δ 7.47−7.42 (m, 2H), 7.36−7.31 (m, 5H), 7.29−7.24 (m, 2H), 7.06−
7.02 (m, 1H), 6.94 (s, 1H), 6.82 (dt, J = 9.9, 2.1 Hz, 1H), 6.75 (d, J =
9.2 Hz, 1H), 6.42 (s, 1H), 2.32 (s, 3H); 13C{1H} NMR (100 MHz,
CDCl3) δ 164.1, 161.6, 153.3, 143.6 (d, J = 10.5 Hz), 141.8, 141.0 (d, J
= 9.0 Hz), 138.2, 130.0, 128.9, 128.0, 127.4, 123.5, 123.1 (d, J = 2.5
Hz), 119.5, 114.0, 113.7, 111.4, 111.1, 77.3, 77.0, 76.7, 21.4; HRMS
(ESI) m/z calcd for C20H17FN2O [M + H]+ 321.1403, found
321.1402; IR (KBr) cm−1 2924, 1663, 1618, 1595, 1531, 1496, 1443,
1322, 1288, 1243, 757, 693.
3-(3-Bromophenyl)-1-(4-methoxyphenyl)-1-phenylurea (4be):
1
140 mg (70%); yellow oil; H NMR (400 MHz, CDCl3) δ 7.59 (t,
J = 1.9 Hz, 1H), 7.36 (dd, J = 10.3, 5.1 Hz, 2H), 7.33−7.28 (m, 3H),
7.25 (ddd, J = 7.2, 3.8, 1.9 Hz, 3H), 7.15−7.07 (m, 2H), 6.96−6.93
(m, 2H), 6.46 (s, 1H), 3.83 (s, 3H); 13C{1H} NMR (100 MHz,
CDCl3) δ 158.7, 153.4, 142.4, 139.9, 134.4, 130.1, 129.3, 129.3, 126.7,
126.3, 126.0, 122.5, 122.0, 117.6, 115.1, 77.3, 77.0, 76.7, 55.5; HRMS
(ESI) m/z calcd for C20H17BrN2O2 [M + H]+ 397.0552, found
397.0546; IR (KBr) cm−1 2920, 2850, 1725, 1679, 1586, 1509, 1480,
1417, 1292, 1245, 1031, 775, 750, 695.
1-(4-Methoxyphenyl)-1-phenyl-3-(3-(trifluoromethyl)phenyl)urea
(4bf): 147 mg (77%); yellow oil; 1H NMR (400 MHz, CDCl3) δ 7.66
(s, 1H), 7.37 (dd, J = 9.1, 2.0 Hz, 3H), 7.34−7.30 (m, 3H), 7.29−7.23
(m, 4H), 6.97−6.94 (m, 2H), 6.57 (s, 1H), 3.83 (s, 3H); 13C{1H}
NMR (100 MHz, CDCl3) δ 167.7, 158.8, 153.5, 142.3, 139.1, 134.3,
130.9, 129.4 (d, J = 10.5 Hz), 128.8, 126.8, 126.4, 122.2, 119.7 (d, J =
3.7 Hz), 115.9 (d, J = 3.8 Hz), 115.2, 77.3, 77.0, 76.7, 55.5; HRMS
(ESI) m/z calcd for C21H17F3N2O2 [M + H]+ 387.1320, found
1-(5-Chloro-2-methoxyphenyl)-1,3-diphenylurea (4p): 146 mg
1
(82%); yellow oil; H NMR (400 MHz, CDCl3) δ 7.38−7.32 (m,
6H), 7.30 (t, J = 2.4 Hz, 1H), 7.27−7.23 (m, 4H), 7.03 (d, J = 7.3 Hz,
1H), 6.93 (d, J = 8.6 Hz, 1H), 6.45 (s, 1H), 3.83 (s, 3H); 13C{1H}
NMR (100 MHz, CDCl3) δ 154.8, 153.4, 141.9, 138.5, 131.9, 130.4,
129.5, 129.0, 128.9, 127.0, 126.8, 125.7, 123.2, 119.3, 113.5, 77.3, 77.0,
76.7, 56.2; HRMS (ESI) m/z calcd for C20H17ClN2O2 [M + H]+
353.1057, found 353.1055; IR (KBr) cm−1 2919, 1684, 1597, 1524,
1495, 1440, 1285, 1237, 1026, 752, 696.
1-(Naphthalen-2-yl)-1,3-diphenylurea (4q): 127 mg (77%); yellow
solid; mp 121−123 °C; 1H NMR (400 MHz, CDCl3) δ 7.89−7.83 (m,
8160
dx.doi.org/10.1021/jo501334u | J. Org. Chem. 2014, 79, 8156−8162

The Journal of Organic Chemistry
Article
387.1315; IR (KBr) cm−1 2959, 2921, 1724, 1681, 1601, 1535, 1509,
1442, 1316, 1247, 1168, 1125, 794, 744, 697.
Ansell, G. K.; Jones, A. D.; Nyce, P.; Chen, M.; Neubert, B. J. Org.
Process Res. Dev. 2008, 12, 666−673. (c) Dai, Y.; Hartandi, K.; Ji, Z.;
Ahmed, A. A.; Albert, D. H.; Bauch, J. L.; Bouska, J. J.; Bousquet, P. F.;
Cunha, G. A.; Glaser, K. B.; Harris, C. M.; Hickman, D.; Guo, J.; Li, J.;
Marcotte, P. A.; Marsh, K. C.; Moskey, M. D.; Martin, R. L.; Olson, A.
M.; Osterling, D. J.; Pease, L. J.; Soni, N. B.; Stewart, K. D.; Stoll, V. S.;
Tapang, P.; Reuter, D. R.; Davidsen, S. K.; Michaelides, M. R. J. Med.
Chem. 2007, 50, 1584−1597. (d) Flipo, M.; Charton, J.; Hocine, A.;
Dassonneville, S.; Deptez, B.; Deprez-Poulain, R. J. Med. Chem. 2009,
52, 6790−6802.
(2) (a) Bigi, F.; Maggi, R.; Sartori, G. Green Chem. 2000, 2, 140−148.
(b) Vishnyakova, T. P.; Golubeva, I. A.; Glebova, E. V. Russ. Chem.
Rev. (Engl. Ed.) 1985, 54, 249−261. (c) Seebach, D.; Beck, A. K.;
Bierbaum, D. J. Chem. Biodiversity 2004, 1, 1111−1239.
1-(4-Methoxyphenyl)-1-phenyl-3-(o-tolyl)urea (4bg): 114 mg
(66%); yellow oil; 1H NMR (400 MHz, CDCl3) δ 7.98 (s, 1H),
7.37 (s, 6H), 7.14 (d, J = 51.4 Hz, 3H), 6.96 (s, 3H), 6.35 (s, 1H), 3.84
(s, 3H), 1.91 (s, 3H); 13C{1H} NMR (100 MHz, CDCl3) δ 158.6,
153.7, 136.8, 134.8, 130.1, 129.3, 126.9, 126.7, 126.0, 123.5, 120.9,
115.1, 77.3, 77.0, 76.7, 55.5, 31.4, 17.3; HRMS (ESI) m/z calcd for
C21H20N2O2 [M + H]+ 333.1603, found 333.1601; IR (KBr) cm−1
2959, 1690, 1588, 1509, 1453, 1307, 1245, 1184, 1032, 967, 752, 695.
3-(2,5-Dimethylphenyl)-1-(4-methoxyphenyl)-1-phenylurea
(4bh): 92 mg (53%); yellow oil; 1H NMR (400 MHz, CDCl3) δ 7.40−
7.32 (m, 6H), 7.25 (dd, J = 12.9, 4.8 Hz, 3H), 7.02 (t, J = 7.3 Hz, 1H),
6.97 (s, 2H), 6.94 (s, 1H), 6.46 (s, 1H), 2.31 (s, 6H); 13C{1H} NMR
(100 MHz, CDCl3) δ 158.6, 153.8, 142.7, 136.6, 134.8, 129.9, 129.3,
126.7, 126.0, 124.2, 123.8, 121.5, 115.0, 77.3, 77.0, 76.7, 55.5, 21.2,
16.8; HRMS (ESI) m/z calcd for C22H22N2O2 [M + H]+ 347.1760,
found 347.1758; IR (KBr) cm−1 2926, 1689, 1582, 1534, 1508, 1485,
1456, 1290, 1246, 1176, 1032, 805, 746, 696.
(3) Lam, P. Y.; Jadhav, P. K.; Eyermann, C. J.; Hodge, C. N.; Ru, Y.;
Bacheler, L. T.; Meek, J. L.; Otto, M. J.; Rayner, M. M.; Wong, Y. N.;
Chang, C. H.; Weber, P. C.; Jackson, D. A.; Sharpe, T. R. Science 1994,
263, 380−384.
(4) (a) Ozaki, S. Chem. Rev. 1972, 72, 457−496. (b) Dudic, M.;
Lhotak, P.; Stibor, I.; Lang, K.; Proskova, P. Org. Lett. 2003, 5, 149−
152. (c) Molina, P.; Fresneda, P. M.; Delgado, S. J. Org. Chem. 2003,
68, 489−499. (d) McElroy, N. R.; Jurs, P. C.; Morisseau, C.;
Hammock, B. D. J. Med. Chem. 2003, 46, 1066−1080. (e) Arduini, A.;
Calzavacca, F.; Pochini, A.; Secchi, A. Chem.Eur. J. 2003, 9, 793−
799.
3-Mesityl-1-(4-methoxyphenyl)-1-phenylurea (4bi): 105 mg
(57%); yellow oil; H NMR (400 MHz, CDCl3) δ 7.34 (d, J = 8.7
1
Hz, 7H), 6.96−6.93 (m, 2H), 6.85 (s, 2H), 5.73 (s, 1H), 3.82 (s, 3H),
2.23 (s, 3H), 2.22 (s, 6H); 13C{1H} NMR (100 MHz, CDCl3) δ 158.4,
154.4, 143.2, 136.4, 135.4, 135.2, 131.9, 129.4, 129.1, 128.8, 126.2,
125.4, 115.0, 77.3, 77.0, 76.7, 55.5, 20.9, 18.4; HRMS (ESI) m/z calcd
for C23H24N2O2 [M + H]+ 361.1916, found 361.1914; IR (KBr) cm−1
2958, 2924, 1684, 1490, 1290, 1246, 1183, 1033, 750, 694.
́
(5) (a) Nudelman, N. S.; Lewkowicz, E. S.; Perez, D. G. Synthesis.
1990, 1990, 917−920. (b) Yang, Y.; Lu, S. Tetrahedron Lett. 1999, 40,
4845−4846.
3-(6-Chloropyridin-3-yl)-1-(4-methoxyphenyl)-1-phenylurea
1
(4bj): 90.5 mg (51%); white solid; mp 153−155 °C; H NMR (400
MHz, CDCl3) δ 8.12 (d, J = 2.6 Hz, 1H), 7.35−7.27 (m, 9H), 6.99−
6.97 (m, 2H), 6.52 (s, 1H), 3.85 (s, 3H); 13C{1H} NMR (100 MHz,
CDCl3) δ 158.9, 153.4, 144.9, 142.1, 140.0, 134.6, 134.1, 129.6, 129.5,
129.3, 126.8, 126.6, 124.1, 115.3, 77.3, 77.0, 76.7, 55.6; HRMS (ESI)
m/z calcd for C19H16ClN3O2 [M + H]+ 354.8096, found 354.8092; IR
(KBr) cm−1 2924, 1690, 1509, 1490, 1290, 1245, 1183, 1032, 750, 695.
1-(4-Methoxyphenyl)-3-phenyl-1-(o-tolyl)urea (4bk): 133.4 mg
(6) McCusker, J. E.; Abboud, K. A.; McElwee-White, L. Organo-
metallics 1997, 16, 3863−3866.
(7) (a) Sartori, G.; Maggi, R. In Science of Synthesis; Ley, S. V., Knight,
J. G., Eds.; Thieme: Stuttgart, 2005; Vol. 18, pp 665−758. (b) Hegarty,
A. F.; Drennan, L. J. In Comprehensive Organic Functional Group
Transformations; Katritzky, A. R., Meth-Cohn, O., Rees, C. W., Eds.;
Pergamon: Oxford, 1995; Vol. 6, pp 499−526.
1
(80%); yellow oil; H NMR (400 MHz, CDCl3) δ 7.31−7.21 (m,
(8) Nowick, J. S.; Powell, N. A.; Nguyen, T. M.; Noronha, G. J. Org.
Chem. 1992, 57, 7364−7366.
10H), 7.03−6.99 (m, 1H), 6.88−6.85 (m, 2H), 6.37 (s, 1H), 3.79 (s,
3H), 2.31 (s, 3H); 13C{1H} NMR (100 MHz, CDCl3) δ 157.3, 153.5,
140.4, 138.6, 136.9, 134.8, 131.9, 129.5, 128.9, 128.3, 127.6, 127.2,
123.1, 119.3, 114.3, 77.3, 77.0, 76.7, 55.5, 18.1; HRMS (ESI) m/z
calcd for C21H20N2O2 [M + H]+ 333.4031, found 333.4029; IR (KBr)
cm−1 2959, 2854, 1690, 1509, 1481, 1290, 1245, 1183, 1032, 752, 696.
(9) For reviews on diaryliodonium salts, see: (a) Yusubov, M. S.;
Maskaev, A. V.; Zhdankin, V. V. ARKIVOC 2011, 370−409.
(b) Merritt, E. A.; Olofsson, B. Angew. Chem., Int. Ed. 2009, 48,
9052−9070. (c) Zhdankin, V. V.; Stang, P. J. Chem. Rev. 2008, 108,
5299−5358. (d) Zhdankin, V. V.; Stang, P. J. Chem. Rev. 2002, 102,
2523−2584. (e) Grushin, V. V. Chem. Soc. Rev. 2000, 29, 315−324.
(f) Stang, P. J.; Zhdankin, V. V. Chem. Rev. 1996, 96, 1123−1178.
(10) (a) Castro, S.; Fernandez, J. J.; Vicente, R.; Fananas, F. J.;
Rodríguez, F. Chem. Commun. 2012, 48, 9089−9091. (b) Hickman, A.
J.; Sanford, M. S. ACS Catal. 2011, 1, 170−174. (c) Chen, B.; Hou, X.
L.; Li, Y. X.; Wu, Y. D. J. Am. Chem. Soc. 2011, 133, 7668−7671.
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ASSOCIATED CONTENT
■
S
* Supporting Information
1H and 13C NMR spectra for all compounds and X-ray
crystallographic data for compound 4m (CIF). This material is
available free of charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
■
Corresponding Authors
*E-mail: glcheng@hqu.edu.cn.
*E-mail: cuixl@hqu.edu.cn.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This work was supported by Minjiang Scholar Program
(10BS216), Xiamen Southern Oceanographic Center
(13GYY003NF16), the Natural Science Foundation of Fujian
Province, China (2013J01050), and Fundamental Research
Funds of Huaqiao University.
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