Synthesis of alkyl-aryl ethers by copper-catalyzed etherization reactions of aryl fluorides with tetraalkylammonium bromides and H2O

Article abstract of DOI:10.1002/cjoc.201090383

Synthesis of alkyl aryl ethers via copper-catalyzed etherizations of electron-deficient aryl fluorides with quaternary ammonium bromides and water has been developed. In the presence of Cu(OAc)₂, POPh₃ (L4) and Cs₂CO₃, a variety of electron-deficient aryl fluorides underwent the reaction with quaternary ammonium bromides and H ₂O in moderate to good yields. The mechanism was also discussed. Synthesis of alkyl aryl ethers via copper-catalyzed etherizations of electron-deficient aryl fluorides with quaternary ammonium bromides and water has been developed. In the presence of Cu(OAc)₂, POPh₃ (L4) and Cs₂CO₃, a variety of electron-deficient aryl fluorides underwent the reaction with quaternary ammonium bromides and H ₂O in moderate to good yields. Copyright

Full text of DOI:10.1002/cjoc.201090383

NOTE
Synthesis of Alkyl-Aryl Ethers by Copper-catalyzed
Etherization Reactions of Aryl Fluorides with
Tetraalkylammonium Bromides and H2O
Wang, Feng(王峰)
Tang, Boxiao(唐伯孝)
Li, Jinheng*(李金恒)
Xie, Yexiang*(谢叶香)
Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education),
Hunan Normal University, Changsha, Hunan 410081, China
Synthesis of alkyl aryl ethers via copper-catalyzed etherizations of electron-deficient aryl fluorides with quater-
nary ammonium bromides and water has been developed. In the presence of Cu(OAc)2, POPh3 (L4) and Cs2CO3, a
variety of electron-deficient aryl fluorides underwent the reaction with quaternary ammonium bromides and H2O in
moderate to good yields. The mechanism was also discussed.
Keywords copper, POPh3, aryl fluoride, quaternary ammonium bromide, alkyl aryl ether, etherization
Introduction
there is no report on the use of tetraalkylammonium
bromides combined with water as nucleophiles for this
process to synthesize alkyl aryl ethers.5
Alkyl aryl ethers are important class of constituents
in a tremendous range of natural products and bioactive
molecules as well as are valuable intermediates in or-
ganic synthesis.1 There are three common transforma-
tions for their synthesis, including (1) nucleophilic sub-
stitution reactions of activated aryl halides with alco-
hols,2 (2) copper-catalyzed Ullmann reactions of aryl
halides with alcohols,3 and (3) palladium-catalyzed
cross-couplings of aryl halides with alcohols.4 However,
all these methods must be performed under basic condi-
tions to form alkoxides, which are sensitive to air and
water. In addition, harmful organic solvents are required
in all cases. Wandless and co-workers,2c for instance,
have reported that electron-deficient aryl fluorides could
undergo the etherization reaction with aliphatic alcohols
smoothly in THF to prepare alkyl aryl ethers in moder-
ate to good yiels. However, stronger bases, such as
KOBu-t or KHMDS [potassium bis(trimethylsilyl)-
amide], were required. For these reasons, the develop-
ment of a new and environmentally benign route to the
synthesis of alkyl aryl ethers is still significant. Here,
we wish to report a novel protocol for the preparation of
alkyl aryl ethers via copper-catalyzed etherization reac-
tions of aryl fluorides with tetraalkylammonium bro-
mides and H2O (Eq. 1). To the best of our knowledge,
Results and discussion
In our recent report on the Cu2O-catalyzed Stille
cross-coupling, 1-n-butoxy-4-nitrobebzene (3aa) was
observed in a 20% yield when 1-fluoro-4-nitrobenzene
(1a) was employed as the substrate, P(o-tol)3 (L1) as the
ligand, KF as the base and (n-Bu)4NBr (TBAB, 2a) as
the medium (Entry 1 in Table 1).6 These prompted us to
optimize the conditions to improve the yield of 3aa.
Initially, a number of bases, including KF, Cs2F,
Cs2CO3, K2CO3 and KOH, were examined, and Cs2CO3
provided the best results. In the presence of Cu2O, L1
and Cs2CO3, treatment of substrate 1a with 2a and H2O
afforded the corresponding product 3aa in a 48% yield
(Entry 2). We then turned our efforts on testing copper
salts as the catalysts (Entries 2—5). The results showed
that Cu(OAc)2 was the most effective catalyst in terms
of yield (61% yield, Entry 5), and no reaction was ob-
served without copper salts. Subsequently, a series of
ligands, such as PPh3 (L2), P(2,6-diMeOC6H3)2 (L3),
POPh3 (L4) and bipyridine (L5), were screened, and
POPh3 (L4) was superior to the other ligands (Entries
6—8). In the presence of Cu(OAc)2, POPh3 (L4) and
Cs2CO3, the yield of 3aa was enhanced to 80% (Entry
8). It is noteworthy that the reaction performed in air
atmosphere gives a low yield (Entry 9). In addition, no
reaction was observed in the presence of solvents, such
as hexane, toluene, THF, MeCN, DMF, DMSO and
*
E-mail: jhli@hunnu.edu.cn; Tel.: 0086-0731-8872576; Fax: 0086-0731-8872101
Received and revised May 19, 2010; accepted July 19, 2010.
Project supported by the New Century Excellent Talents in University (No. NCET-06-0711), Hunan Normal University (No. 20801), the National
Natural Science Foundation of China (No. 20872112) and Fok Ying Tung Education Foundation (No. 101012).
2318
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Chin. J. Chem. 2010, 28, 2318— 2322

Synthesis of Alkyl-Aryl Ethers by Copper-catalyzed Etherization Reactions
Et3N. The results also disclosed that the amount of wa-
ter affected the reaction to some extent, and the yield of
3aa was reduced either in the absence of H2O or in the
presence of 6 equiv. of H2O (Entries 8 and 10). It is
worth noting that a moderate yield of 3aa was still iso-
lated without Cu(OAc)2 or/and POPh3 (L4) (Entries 11
and 12). Finally, the loading of TBAB and temperature
effects were also investigated (Entries 13 — 16). It
turned out that 6 equiv. of TBAB at 145 ℃ provided
the best results (Entry 8). We found that a mixture of
products was observed when the reaction was conducted
at 180 ℃ without Cu and POPh3 (Entry 13). It was
happy to observe that a good yield of 3aa was still ob-
tained from the reaction of 2 mmol of substrate 1a (En-
try 16). However, no reaction was observed using
(n-Bu)4NCl or (n-Bu)4NI instead of TBAB (Entries 17
and 18).
standard conditions (Table 2). We were delighted to
find that nitro-substituted aryl fluorides 1b— 1h af-
forded satisfactory results in the presence of Cu(OAc)2,
L4 and Cs2CO3, and fluorides bearing chloro, butoxy
and trifluoromethyl substituents were tolerated well
(Entries 1—7). Interestingly, the reaction of substrate 1e
with TBAB and H2O gave a moderate yield together
with the occurrence of displacement reaction (Entry 4).
It was pleased to discover that difluorobenzenes 1g and
1h were selectively reacted with TBAB and H2O under
the standard conditions to provide the mono-butoxy-
substituted products 3ga and 3ha in good yields (Entries
6 and 7). Unfortunately, a mixture of products was ob-
served from the reaction of 1,3,5-trifluoro-2-nitroben-
zene 1i (Entry 8). We found that the yields of the target
products were reduced using fluorobenzonitriles 1j and
1k as the substrates (Entries 9 and 10). For instance,
only 30% yield of the desired product was isolated
when 4-fluorobenzonitrile (1j) was treated with TBAB,
H2O•Cu(OAc)2, L4 and Cs2CO3 after 36 h (Entry 9).
However, attempt to etherization of 1-chloro-2,4-
dinitrobenzene with TBAB and H2O failed (Entry 11). It
is noteworthy that other aryl fluorides, including
1-fluoro-4-(trifluoromethyl)benzene (1l), 1-(4-fluoro-
phenyl)-ethanone (1m), fluorobenzene (1n) and
4-fluoroanisole (1o), are not suitable substrates for the
reaction under the standard conditions.
Table 1 Copper-catalyzed cross-coupling of 1-fluoro-4-nitro-
benzene (1a) with TBAB (2a) and H2Oa
Entry
[Cu]
Ligand
Yieldb/%
1c
2
3
4
5
6
7
8
Cu2O
Cu2O
P(o-tol)3 (L1)
P(o-tol)3 (L1)
(L1)
20
48
Screening the etherization reaction of substrate 1a
with several commercially available quaternary ammo-
nium bromides (2) is listed in Scheme 1. Quaternary
ammonium bromides, such as (n-C3H7)4NBr (2c),
(n-C7H15)4NBr (2d), (n-C8H17)4NBr (2e), (benzyl)-
(Et)3NBr (2f), (benzyl)(n-C4H9)3NBr (2g), and
(ally)(n-C4H9)3NBr (2h) except Et4NBr (2b), all per-
formed the reaction successfully under the standard
conditions. It is worth noting that both (benzyl)(Et)3NBr
(2f) and (benzyl)(n-C4H9)3NBr (2g) selectively afford
the same product 3af alone, whereas (ally)(n-C4H9)3NBr
(2h) gave a mixture of two products 3ah and 3aa (molar
ratio: 1∶3).
CuI
18
CuBr2
(L1)
43
Cu(OAc)2
Cu(OAc)2
(L1)
61
PPh3 (L2)
Trace
32
Cu(OAc)2 P(2,6-diMeOC6H3)2 (L3)
Cu(OAc)2
POPh3 (L4)
(L4)
(L4)
(L4)
⎯
80
9d Cu(OAc)2
10e Cu(OAc)2
25
56
11
12
13f
⎯
⎯
⎯
50
48
Scheme 1 Etherizations of substrate 1a with commercially
available quaternary ammonium bromides (2)
⎯
Mixture
25
14g Cu(OAc)2
15h Cu(OAc)2
16i Cu(OAc)2
17j Cu(OAc)2
18k Cu(OAc)2
(L4)
(L4)
(L4)
(L4)
(L4)
49
82
Trace
Trace
a
Reaction conditions: 1a (0.5 mmol), H2O (3 equiv.), TBAB (6
equiv.), [Cu] (10 mol%), ligand (20 mol%) and Cs2CO3 (2 equiv.)
b
c
A working mechanism was proposed as outlined in
Scheme 2.1-4 Substrate 2 readily undergoes the radical
reaction to afford the radical intermediate A under
heating and Cu conditions,5,7 followed by performing
the reaction according to the SNAr mechanism.2-4 There
are at least two roles of Cu(OAc)2 in the reaction: (i)
stability of the radical intermediate A, and (ii) catalyst
for the SNAr reaction.
at 145 ℃ for 24 h. Isolated yield. KF (2 equiv.) instead of
Cs2CO3. d Under air atmosphere. e H2O (6 equiv.). f At 180 ℃ in
g
h
high-pressure reaction vessel. At 120 ℃. TBAB (3 equiv.).
i
j
1a (2 mmol). (n-Bu)4NCl (6 equiv.) instead of TBAB.
k (n-Bu)4NI (6 equiv.) instead of TBAB.
Subsequently, a variety of aryl fluorides were sur-
veyed to investigate scope of the reaction under the
Chin. J. Chem. 2010, 28, 2318— 2322
© 2010 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
2319

Wang et al.
NOTE
Table 2 Copper-catalyzed cross-coupling of aryl fluorides (1) with TBAB (2a) and H2Oa
Entry
1
Substrate
t/h
Product
Isolated yieldb/%
24
87
96
64
2
3
45
46
4
5
48
36
38
90
46
40
48
36
48
48
60
86
6
7
8
9
Mixture
N.D.b
30
10
11
35
trace
a Reaction conditions: 1 (0.5 mmol), H2O (3n equiv.), 2a (6n equiv.), Cu(OAc)2•H2O (10n mol%), L4 (20n mol%) and Cs2CO3 (2n equiv.)
at 145 ℃. n＝number of fluoro and methoxy groups. b Not determined.
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Chin. J. Chem. 2010, 28, 2318— 2322

Synthesis of Alkyl-Aryl Ethers by Copper-catalyzed Etherization Reactions
Scheme 2 A possible mechanism
(CDCl3, 400 MHz) δ: 8.24—8.19 (m, 2H), 7.53 (d, J＝
7.2 Hz, 2H), 7.45—7.37 (m, 3H), 7.01 (d, J＝8.0 Hz,
1H), 4.09 (t, J＝6.0 Hz, 2H), 1.84—1.77 (m, 2H),
1.54—1.48 (m, 2H), 0.93 (t, J＝7.2 Hz, 3H); 13C NMR
(CDCl3, 100 MHz) δ: 161.1, 141.2, 136.3, 131.3, 129.4,
128.1, 127.8, 126.4, 124.7, 11＋1.4, 68.9, 30.8, 19.1, 13.7;
LRMS (EI) m/z (%): 271 (M , 37), 215 (100); HRMS
(EI) calcd for C16H17NO3 (M ＋ ) 271.1208, found
271.1208.
In summary, we describe here the first example of
constructing C—O bond via copper-catalyzed reaction
of the electron-deficient aryl fluorides with quaternary
ammonium bromides and water. Work to probe the de-
tailed mechanism and apply the reaction in organic syn-
thesis is currently underway.
2,4-Dibutoxy-1-nitrobenzene (3da) Colorless oil;
1H NMR (CDCl3, 400 MHz) δ: 7.96 (d, J＝8.8 Hz, 1H),
6.50 (s, 1H), 6.47 (d, J＝9.2 Hz, 1H), 4.07 (t, J＝6.0 Hz,
2H), 4.02 (t, J＝6.4 Hz, 2H), 1.86—1.77 (m, 4H),
1.55—1.49 (m, 4H), 1.01—0.96 (m, 6H); 13C NMR
(CDCl3, 100 MHz) δ: 164.2, 155.2, 132.8, 128.2, 104.9,
100.6, 69.2, 6＋8.4, 31.0, 30.9, 19.1, 13.7; LRMS (EI) m/z
(%): 267 (M , 26), 21＋1 (9), 155 (100); HRMS (EI)
calcd for C14H21NO4 (M ) 267.1471, found 267.1470.
1-Butoxy-2-nitro-4-(trifluoromethyl)benzene (3fa)
Experimental
The NMR spectroscopy was performed on an
INOVA-400 (Varian) spectrometer operating at 400
MHz (1H NMR) and 100 MHz (13C NMR). TMS
(tetramethylsilane) was used an internal standard and
CDCl3 was used as the solvent. Mass spectrometric
analysis was performed on GC-MS analysis (SHIMA-
DZU GCMS-QP2010).
1
Colorless oil; H NMR (CDCl3, 400 MHz) δ: 8.10 (s,
1H), 7.77 (d, J＝8.8 Hz, 1H), 7.18 (d, J＝8.8 Hz, 1H),
4.18 (t, J＝10.4 Hz, 2H), 1.87—1.83 (m, 2H), 1.55—
1.49 (m, 2H), 0.99 (t, J＝7.6 Hz, 3H); 13C NMR (CDCl3,
100 MHz) δ: 154.8, 130.8 (d, J＝3.1 Hz, 1C), 124.5,
123.2 (d, J＝3.8 Hz, 1C), 122.6, 112.3, 114.6, 69.9,
30.8, 19.0, 13.6; LRMS (EI) m/z (%): 263 (M＋, 6), 207
(15), 188 (6), 56 (100); HRMS (EI) calcd for
C11H12F3NO3 (M＋) 263.0769, found 263.0767.
Typical experimental procedure for the copper-
catalyzed etherization reaction
A mixture of aryl fluoride 1 (0.5 mmol), H2O (3n
equiv.), R4NBr 2 (6n equiv.), Cu(OAc)2•H2O (10n
mol%), L4 (20n mol%) and Cs2CO3 (2n equiv.) (n＝
number of fluoro and methoxy groups) was stirred at
145 ℃ under argon atmosphere for the indicated time
in Tables 1 and 2 and Scheme 1 until complete con-
sumption of starting material as monitored by TLC. Af-
ter the reaction was finished, diethyl ether was poured
into the mixture, then washed with water, dried with
anhydrous Na2SO4 and evaporated under vacuum. The
residue was purified by flash column chromatography
(hexane or hexane/ethyl acetate) to afford the desired
coupled product.
4-Butoxy-2-fluoro-1-nitrobenzene (3ga)9 Color-
1
less oil; H NMR (CDCl3, 400 MHz) δ: 7.94, 7.92 (dd,
J＝5.6 Hz, 5.6 Hz, 1H), 6.77 (d, J＝10.4 Hz, 1H), 6.73
—6.79 (m, 1H), 4.09 (t, J＝6.4 Hz, 2H), 1.86—1.82 (m,
2H), 1.56—1.51 (m, 2H), 0.99 (t, J＝7.6 Hz, 3H);
13C NMR (CDCl3, 100 MHz) δ: 167.2, 164.7, 155.1 (d,
J＝11.4 Hz, 1C), 128.2 (d, J＝11.4 Hz, 1C), 107.3 (d,
J＝12.8 Hz, 1C), 102.3 (d, J＝26.7 Hz,＋1C), 70.0, 31.2,
19.3, 14.0; LRMS (EI) m/z (%): 213 (M , 17), 157 (31),
141 (10), 127 (16), 56 (100).
1-Butoxy-2-fluoro-4-nitrobenzene (3ha) Color-
1-Butoxy-4-nitrobenzene (3aa)7 Slight yellow oil;
1H NMR (CDCl3, 400 MHz) δ: 8.18 (d, J＝9.2 Hz, 2H),
6.94 (d, J＝9.2 Hz, 2H), 4.06 (t, J＝6.0 Hz, 2H), 1.84—
1.77 (m, 2H), 1.54—1.48 (m, 2H), 0.99 (t, J＝7.2 Hz,
3H); 13C NMR (CDCl3, 100 MHz) δ: 164.1, 141.2,
125.8, 114.3, 68.5, 30.9, 19.1, 13.7; LRMS (EI) m/z (%):
195 (M＋, 59), 139 (96), 140 (80), 123 (32), 109 (55), 56
(87), 41 (100).
1
less oil; H NMR (CDCl3, 400 MHz) δ: 8.05 (d, J＝8.8
Hz, 1H), 7.97 (d, J＝10.8 Hz, 1H), 7.03 (t, J＝8.0 Hz,
1H), 4.10 (t, J＝6.4 Hz, 2H), 1.86—1.82 (m, 2H),
1.56—1.51 (m, 2H), 0.99 (t, J＝7.6 Hz, 3H); 13C NMR
(CDCl3, 100 MHz) δ: 153.0 (d, J＝9.8 Hz, 1C), 152.4,
149.9, 120.8 (d, J＝3.1 Hz, 1C), 112.7 (d, J＝1.5 Hz,
1C), 112.1 (d, J＝2.8 Hz, 1C), 69.5, 30.8, 19.0, 13.7;
LRMS (EI) m/z (%): 213 (M＋, 12), 143 (23), 57 (100);
HRMS (EI) calcd for C10H12FNO3 (M＋ ) 213.0801,
found 213.0801.
1-Butoxy-2-chloro-4-nitrobenzene (3ba)8 Color-
1
less oil; H NMR (CDCl3, 400 MHz) δ: 8.29 (s, 1H),
4-Butoxybenzonitrile (3ja)7
Colorless oil;
8.15 (d, J＝9.2 Hz, 1H), 6.97 (d, J＝8.8 Hz, 1H), 4.14 (t,
J＝6.4 Hz, 2H), 1.90—1.84 (m, 2H), 1.58—1.53 (m,
2H), 1.00 (t, J＝7.2 Hz, 3H); 13C NMR (CDCl3, 100
MHz) δ: 159.8, 140.9, 126.0, 124.0, 123.4, 111.6, 69.6,
30.8, 19.1, 13.7; LRMS (EI) m/z (%): 231 (M＋＋2, 9),
229 (M＋, 28), 175 (19), 173 (51), 145 (8), 143 (27), 129
(3), 127 (9), 101 (4), 99 (11), 63 (17), 56 (100).
1H NMR (CDCl3, 400 MHz) δ: 7.57 (d, J＝8.8 Hz, 2H),
6.93 (d, J＝9.2 Hz, 2H), 4.00 (t, J＝6.4 Hz, 2H), 1.81—
1.77 (m, 2H), 1.52—1.47 (m, 2H), 0.96 (t, J＝7.2 Hz,
3H); 13C NMR (CDCl3, 100 MHz) δ: 162.4, 133.9,
119.3, 115.1, 10＋3.6, 68.1, 30.9, 19.1, 13.7; LRMS (EI)
m/z (%): 175 (M , 22), 119 (100).
2,6-Dibutoxybenzonitrile (3ka)10 Colorless oil;
1H NMR (CDCl3, 100 MHz) δ: 7.37 (t, J＝8.0 Hz, 1H),
1-Butoxy-2-phenyl-4-nitrobenzene (3ca) Slight
1
yellow solid, m.p. 81—82 ℃ (uncorrected); H NMR
Chin. J. Chem. 2010, 28, 2318— 2322
© 2010 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.cjc.wiley-vch.de
2321

Wang et al.
NOTE
2004, 6, 2551.
6.50 (d, J＝8.4 Hz, 2H), 4.05 (t, J＝6.8 Hz, 4H), 1.83—
1.80 (m, 4H), 1.56—1.50 (m, 4H), 0.98 (t, J＝7.2 Hz,
6H); 13C NMR (CDCl3, 100 MHz) δ: 162.3, 134.4,
114.0, 104.0, 91.8, 68.8, 30.9, 19.1, 13.8; LRMS (EI)
m/z (%): 247 (M＋, 22), 191 (81), 135 (100).
(e) Grecian, S. A.; Hadida, S.; Warren, S. D. Tetrahedron
Lett. 2005, 46, 4683.
(f) Rodriguez, J. R.; Agejas, J.; Bueno, A. B. Tetrahedron
Lett. 2006, 47, 5661 and references cited therein.
(a) Lindley, J. Tetrahedron 1984, 40, 1433.
(b) Aalten, H. L.; van Koten, G.; Grove, D. M.; Kuilman, T.;
Piekstra, O. G.; Hulshof, L. A.; Sheldon, R. A. Tetrahedron
1989, 45, 5565.
(c) Keegstra, M. A.; Peters, T. H. A.; Brandsma, L.
Tetrahedron 1992, 48, 3633.
(d) Capdevielle, P.; Maumy, M. Tetrahedron Lett. 1993, 34,
1007.
(e) Wolter, M.; Nordmann, G.; Job, G. E.; Buchwald, S. L.
Org. Lett. 2002, 4, 973.
(f) Job, G. E.; Buchwald, S. L. Org. Lett. 2002, 4, 3703.
(g) Manbeck, G. F.; Lipman, A. J.; Stockland, R. A. Jr.;
Freidl, A. L.; Hasler, A. F.; Stone, J. J.; Guzei, I. A. J. Org.
Chem. 2005, 70, 244.
(a) Palucki, M.; Wolfe, J. P.; Buchwald, S. L. J. Am. Chem.
Soc. 1996, 118, 10333.
(b) Mann, G.; Hartwig, J. F. J. Am. Chem. Soc. 1996, 118,
13109.
(c) Palucki, M.; Wolfe, J. P.; Buchwald, S. L. J. Am. Chem.
Soc. 1997, 119, 3395.
(d) Mann, G.; Hartwig, J. F. J. Org. Chem. 1997, 62, 5413.
(e) Watanabe, M.; Nishiyama, M.; Koie, Y. Tetrahedron
Lett. 1999, 40, 8837.
(f) Torraca, K. E.; Kuwabe, S.-I.; Buchwald, S. L. J. Am.
Chem. Soc. 2000, 122, 12907.
(g) Parrish, C. A.; Buchwald, S. L. J. Org. Chem. 2001, 66,
2498 and references cited therein.
(h) Vorogushin, A. V.; Huang, X.; Buchwald, S. L. J. Am.
Chem. Soc. 2005, 127, 8146.
Pan, Y.; Zhang, Z.; Hu, H. Synthesis 1995, 245.
(a) Li, J.-H.; Tang, B.-X.; Tao, L.-M.; Liang, Y.; Zhang,
M.-B. J. Org. Chem. 2006, 71, 7488.
(b) Xie, Y.-X.; Wang, J.; Li, J.-H.; Liang, Y. Chin. J. Chem.
2008, 26, 2261.
(c) Tao, L.; Xie, Y.; Deng, C.; Li, J. Chin. J. Chem. 2009,
27, 1365.
1-Nitro-4-propoxybenzene (3ac)11 Slight yellow
3
1
oil; H NMR (CDCl3, 400 MHz) δ: 8.18 (d, J＝9.2 Hz,
2H), 8.94 (d, J＝9.2 Hz, 2H), 4.01 (t, J＝6.4 Hz, 2H),
1.88—1.81 (m, 2H), 1.06 (t, J＝7.2 Hz, 3H); 13C NMR
(CDCl3, 100 MHz) δ: 164.3, 141.3, 126.0, 114.4, 70.3,
22.4, 10.4; LRMS (EI) m/z (%): 181 (M＋, 43), 139
(100).
1-(Heptyloxy)-4-nitrobenzene (3ad)12 Slight yel-
1
low oil; H NMR (CDCl3, 400 MHz) δ: 8.20 (d, J＝8.8
Hz, 2H), 6.95 (d, J＝9.2 Hz, 2H), 4.06 (t, J＝6.4 Hz,
2H), 1.85—1.81 (m, 2H), 1.49—1.44 (m, 2H), 1.37—
1.20 (m, 6H), 0.87 (t, J＝7.2 Hz, 3H); 13C NMR (CDCl3,
100 MHz) δ: 164.3, 141.3, 125.9, 114.4, 68.9, 31.9, 29＋.2
(2C), 25.9, 22.6, 14.1; LRMS (EI) m/z (%): 237 (M ,
21), 139 (12), 123 (15), 109 (23), 98 (18), 70 (18), 57
(100).
4
1-Nitro-4-(octyloxy)benzene (3ae)12 Slight yel-
1
low oil; H NMR (CDCl3, 400 MHz) δ: 8.19 (d, J＝9.6
Hz, 2H), 6.94 (d, J＝9.2 Hz, 2H), 4.05 (t, J＝6.4 Hz,
2H), 1.84—1.80 (m, 2H), 1.46—1.42 (m, 2H), 1.35—
1.29 (m, 8H), 0.88 (t, J＝7.2 Hz, 3H); 13C NMR (CDCl3,
100 MHz) δ: 164.3, 141.2, 125.8, 114.3, 68.8, 31.7, 29.2,
29.＋1, 28.9, 25.9, 22.6, 14.0; LRMS (EI) m/z (%): 251
(M , 100).
1-((4-Nitrophenoxy)methyl)benzene
(3af)13
Slight yellow solid, m.p. 103.2—103.7 ℃ (uncorrected,
lit.13 m.p. 102—105 ℃); 1H NMR (CDCl3, 400 MHz) δ:
8.18 (d, J＝9.2 Hz, 2H), 7.42—7.36 (m, 5H), 7.01 (d,
J＝9.2 Hz, 2H), 5.15 (s, 2H); 13C NMR (CDCl3, 100
MHz) δ: 163.8, 141.7, 135.6, 128.9, 128.3, 127.6, 126.0,
114.9, 70.7; LRMS (EI) m/z (%): 229 (M＋, 3), 108 (3),
91 (100).
5
6
1-(Allyloxy)-4-nitrobenzene (3ah)14 Slight yellow
1
oil; H NMR (CDCl3, 400 MHz) δ: 8.21 (d, J＝9.6 Hz,
2H), 6.99 (d, J＝9.2 Hz, 2H), 6.10—6.00 (m, 1H), 5.44,
5.35 (dd, J＝13.2, 10.4 Hz, 2H), 4.66 (d, J＝5.2 Hz,
2H); 13C NMR (CDCl3, 100 MHz) δ: 163.4, 141.3,
131.7, 125.7, 118.4, 114.5, 69.2; LRMS (EI) m/z (%):
179 (M＋, 14), 149 (3), 109 (1), 63 (7), 41 (100).
(d) Xie, Y.-X.; Deng, C.-L.; Pi, S.-F.; Li, J.-H.; Yin, D.-L.
Chin. J. Chem. 2006, 24, 1290.
Aki, S.; Nishi, T.; Minamikawa, J. Chem. Lett. 2004, 33,
940.
McMaster, L.; Magill, A. C. J. Am. Chem. Soc. 1928, 50,
3038.
Kimura, M.; Sekiguchi, S.; Matsui, K. Kogyo Kagaku
Zasshi 1970, 73, 513.
7
8
9
References
1
For a selected review, see: Comprehensive Natural Prod-
ucts Chemistry, Vols. 1, 3, 8., Eds.: Barton, D.; Nakanishi,
K.; Meth-Cohn, O., Elservier Science, Oxford, UK, 1999,
For selected papers, see:
10 Huang, C.; Liu, W.; Yi, S.; Li, H. CN 200610019307.1 2006,
[Chem. Abstr. 2006, 146, 27633].
11 Han, B. H.; Shin, D. H.; Cho, S. Y. Tetrahedron Lett. 1985,
26, 6233.
2
(a) DeVries, V. G.; Moran, D. B.; Allen, G. R.; Riggi, S. J. J.
Med. Chem. 1976, 19, 946.
12 Wada, S.; Urano, M.; Suzuki, H. J. Org. Chem. 2002, 67,
8254.
(b) Pearson, A. J.; Gelormini, A. M. J. Org. Chem. 1995, 60,
281.
(c) Woiwode, T. F.; Rose, C.; Wandless, T. J. J. Org. Chem.
1998, 63, 9594.
13 Shah, S. T. A.; Khan, K. M.; Hussain, H.; Anwar, M. U.;
Fecker, M.; Voelter, W. Tetrahedron 2005, 61, 6652.
14 Ganguly, N. C.; Dutta, S.; Datta, M. Tetrahedron Lett. 2006,
47, 5807.
(d) Kumazawa, K.; Ishihara, K.; Yamamoto, H. Org. Lett.
(E0903262 Zhao, C.)
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