JOURNAL OF CHEMICAL RESEARCH 2016 263
CF SO
3
3
Visible Light
Eosin Y (5 mol%)
O
I
B(OH)2
O N
t-BuONa, DMF, r. t.
O N
NO2
2
O N
air
2
2
1i
2e
3q, 85%
Scheme 2
CF SO
3
3
I
Visible Light
Eosin Y (5 mol%)
B(OH)2
OH
O
t-BuONa, DMF, air
t-BuONa, DMF
Scheme 3 Proposed reaction pathway.
Experimental
All experiments were conducted under air. All solvents were
commercially available. For column chromatography, 200–300 mesh
silica gel was employed. H NMR and C NMR spectra were recorded
on 400 MHz and 500 MHz ( C at 125 MHz) spectrometers in CDCl
solution and the chemical shifts are reported in parts per million (δ)
relative to internal TMS (0 ppm). HRMS were obtained by TOF,
on an Agilent 6540 instrument. Melting points were determined
without correction. Unless otherwise noted, materials obtained
from commercial suppliers were used without further purification.
Compound 3a–3m are reported in the literature, and all spectral data
7.42–7.38 (m, 2H), 7.22–7.18 (m, 1H), 7.08–7.06 (m, 2H), 7.01–6.99 (m,
13
2
1
H); C NMR (CDCl , 125 MHz) δ 196.8, 162.0, 155.5, 131.9, 130.6,
3
24.6, 120.2, 117.3, 29.7.
21
1
13
2-Phenoxynaphthalene (3g): pale red solid; m.p. 48–49 °C (lit.
1
13
m.p. 47–48 °C); H NMR (CDCl , 400 MHz) δ 8.22–8.20 (m, 1H),
3
3
7
.89–7.62 (m, 1H), 7.55–7.49 (m, 2H), 7.41–7.35 (m, 3H), 7.13–7.10
13
(m, 1H), 7.06–7.04 (m, 2H), 6.97–6.95 (m, 1H); C NMR (CDCl , 125
3
MHz) δ 157.9, 153.0, 134.9, 129.8, 127.7, 126.6, 125.9, 125.8, 123.4,
23.1, 122.1.
-Phenoxypyridine (3h): slightly yellow oil; H NMR (CDCl , 400 MHz)
1
1
3
3
δ 8.21–8.20 (m, 1H), 7.70–7.66 (m, 1H), 7.42–7.38 (m, 2H), 7.16–7.14 (m,
13
1
0,21–23
2H), 7.01–6.97 (m, 1H), 6.91–6.89 (m, 1H); C NMR (CDCl , 125 MHz) δ
correspond to those of the literature,
3n–3p are new compounds.
3
1
63.8, 154.2, 147.8, 139.4, 129.7, 124.6, 121.2, 118.4, 111.5.
-Methoxy-4-phenoxybenzene (3i): light yellow oil; H NMR
(CDCl , 400 MHz) δ 7.34–7.29 (m, 2H), 7.06–7.02 (m, 1H), 7.00–6.93
Synthesis of diphenyl ether derivatives; general procedure
1
1
A solution of the appropriate arylboronic acid (1.0 mmol), the
diphenyliodonium trifluoromethanesulfonate (1.2 mmol), eosin Y (34.5
mg, 0.02 mmol) and t-BuONa (1.1 mmol, 25 mg) in DMF (2.0 mL) in
a borosilicate flask was subjected to constant irradiation with an LED
3
13
(m, 4H), 6.91–6.86 (m, 2H), 3.83 (s, 3H); C NMR (125 MHz, CDCl3)
δ 158.8, 156.1, 150.2, 129.7, 122.6, 121.0, 117.7, 115.0, 55.8.
1
Ethyl 3-phenoxybenzoate (3j): colourless oil; H NMR (CDCl , 400
3
1
8-watt visible light, and the reaction was stirred at room temperature
MHz) δ 8.01 (d, J = 8.8 Hz, 2H), 7.39 (t, J = 8.0 Hz, 2H), 7.19 (t, J = 7.4
Hz, 1H), 7.06 (d, J = 8.0 Hz, 2H), 7.00–6.97 (m, 2H), 4.36 (q, J = 7.1
for 1–2 h. After completion of the reaction (TLC), the reaction mixture
was poured into H O (50 mL) and stirred for another 2 h. The aqueous
phase was extracted with CH Cl (2 × 20 mL). The combined organic
phases were dried (Na SO ) and concentrated in vacuo. The residues was
13
Hz, 2H), 1.38 (t, J = 7.1 Hz, 3H); C NMR (CDCl , 125 MHz) δ 166.2,
2
3
161.7, 155.7, 131.6, 130.0, 124.9, 124.4, 120.0, 117.3, 60.8, 14.4.
2
2
1
1-Nitro-2-phenoxybenzene (3k): yellow oil; H NMR (CDCl , 400
2
4
3
purified by silica gel column chromatography [ethyl acetate – petroleum
ether (60–90 °C) = 1:10–1:4] to afford the pure product.
MHz) δ 7.95 (dd, J = 8.2, 1.6 Hz, 1H), 7.53–7.47 (m, 1H), 7.40–7.36
13
(m, 2H), 7.21–7.17 (m, 2H), 7.07–7.00 (m, 3H); C NMR (CDCl , 125
3
1
Diphenyl ether (3a): colourless oil; H NMR (CDCl , 400 MHz)
MHz) δ 155.8, 150.7, 134.1, 130.1, 125.7, 124.6, 123.1, 120.5, 119.3.
3
21
δ 7.37–7.33 (m, 4H), 7.12 (d, J = 7.4 Hz, 2H), 7.04–7.02 (m, 4H);
1-Nitro-4-phenoxybenzene (3l): yellow solid; m.p. 57–59 °C (lit.
13
1
C NMR (CDCl , 125 MHz) δ 157.2, 129.7, 123.2, 118.9.
m.p. 58–59 °C); H NMR (CDCl , 400 MHz) δ 8.22–8.18 (m, 2H),
3
3
1
1-Fluoro-4-phenoxybenzene (3b): light yellow oil; H NMR (CDCl ,
7.46–7.42 (m, 2H), 7.28–7.24 (m, 1H), 7.11–7.08 (m, 2H), 7.03–7.00 (m,
3
13
4
00 MHz) δ 7.36–7.31 (m, 2H), 7.11–7.07 (m, 1H), 7.06–6.09 (m, 6H);
2H); C NMR (CDCl , 125 MHz) δ 163.4, 154.7, 142.6, 130.3, 125.9,
3
1
3
C NMR (CDCl , 125 MHz) δ 159.8, 157.9, 157.7, 152.9, 129.7, 123.1,
125.4, 120.5, 117.1.
3
2
2
1
20.6, 120.5, 118.2, 116.4, 116.2.
2-Phenoxybiphenyl (3m): light yellow solid; m.p. 48–50 °C (lit.
1
1
1-Chloro-4-phenoxybenzene (3c): light yellow oil; H NMR (CDCl ,
m.p. 49–50 °C); H NMR (CDCl , 400 MHz) δ 7.58–7.55 (m, 4H),
3
3
4
00 MHz) δ 7.37–7.32 (m, 2H), 7.30–7.27 (m, 2H), 7.14–7.10 (m, 1H),
7.45–7.42 (m, 2H), 7.38–7.31 (m, 3H), 7.15–7.11 (m, 1H), 7.09–7.06 (m,
13
13
7.01–6.99 (m, 2H), 6.95–6.93 (m, 2H); C NMR (CDCl , 125 MHz) δ
4H); C NMR (CDCl , 125 MHz) δ 157.1, 156.8, 140.6, 136.3, 129.8,
3
3
1
56.9, 155.9, 129.8, 129.7, 128.2, 123.6, 120.0, 118.9.
128.7, 128.4, 127.0, 126.9, 123.4, 119.0; m/z: HRMS (ESI) calcd for:
1
1-Bromo-3-phenoxybenzene (3d): light yellow oil; H NMR (CDCl ,
C H O [M + H] 247.1123; found: 247.1128.
3
18 15
4
6
1
00 MHz) δ 7.39–7.35 (m, 2H), 7.22–7.14 (m, 4H), 7.04–7.01 (m, 2H),
4ꞌ-Fluoro-2-phenoxybiphenyl (3n): light yellow solid; m.p.
13
1
.96–6.92 (m, 1H); C NMR (CDCl , 125 MHz) δ 158.4, 156.3, 130.8,
58–60 °C; H NMR (CDCl , 400 MHz) δ 7.53–7.49 (m, 2H), 7.43 (dd,
3
3
29.9, 126.1, 124.0, 122.8, 121.7, 119.4, 117.2.
J = 7.6, 1.7 Hz, 1H), 7.33–7.25 (m, 3H), 7.23–7.21 (m, 1H), 7.07–7.00
1
13
1-tert-Butyl-4-phenoxybenzene (3e): colourless oil;
H
NMR
(m, 4H), 6.92–6.90 (m, 2H); C NMR (CDCl , 125 MHz) δ 163.2,
3
(
(
CDCl , 400 MHz) δ 7.36–7.31 (m, 4H), 7.11–7.07 (m, 1H), 7.03–7.00
161.2, 157.6, 153.5, 133.6, 132.7, 131.1, 130.8, 130.7, 129.6, 128.6, 124.1,
3
13
m, 2H), 6.96–6.94 (m, 2H), 1.33 (s, 9H); C NMR (CDCl , 125 MHz)
122.7, 120.2, 118.1, 115.1, 114.9; m/z: HRMS (ESI) calcd for: C H FO
3
18 14
δ 157.6, 154.7, 146.1, 129.6, 118.6, 118.4, 34.3, 31.5.
-(4-Phenoxyphenyl)ethanone (3f): yellow solid; m.p. 49–51 °C
[M + H] 265.1028; found: 265.1032.
1
3ꞌ-Methyl-2-phenoxybiphenyl (3o): light yellow solid; m.p.
21
1
1
(
lit. m.p. 50–52 °C); H NMR (CDCl , 400 MHz) δ 7.95–7.93 (m, 2H),
65–67 °C; H NMR (CDCl , 400 MHz) δ 7.45 (dd, J = 7.6, 1.8 Hz, 1H),
3
3