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Hao Liang et al. / Chinese Journal of Catalysis 36 (2015) 113–118
(100 MHz, CDCl3) δ 169.2, 147.6, 144.1, 139.2, 126.8, 123.8,
107.1, 24.1.
N‐[1‐(4‐Fluorophenyl)vinyl]acetamide (3e). 1H NMR (400
MHz, CDCl3) δ 7.36–7.33 (t, J = 7.2 Hz, 2H), 7.28 (s, 1H),
7.02–6.98 (t, J = 8.4 Hz, 2H), 5.67 (s, 1H), 4.99 (s, 1H), 2.02 (s,
3H). 13C NMR (100 MHz, CDCl3) δ 169.3, 162.8 (JCF = 247.2 Hz),
139.7, 134.3, 127.9 (JCF = 8.2 Hz), 115.4 (JCF = 21.4 Hz), 103.1,
24.2.
N‐[1‐(4‐Chlorophenyl)vinyl]acetamide (3f). 1H NMR (400
MHz, CDCl3) δ 7.31 (s, 5H), 5.70 (s, 1H), 5.06 (s, 1H), 2.06 (s,
3H). 13C NMR (100 MHz, CDCl3) δ 169.4, 139.6, 136.5, 134.4,
128.7, 127.4, 103.7, 24.2.
N‐[1‐(4‐Bromophenyl)vinyl]acetamide (3g). 1H NMR (400
MHz, CDCl3) δ 7.47 (d, J = 8.0 Hz, 2H), 7.27 (d, J = 8.0 Hz, 2H),
7.11 (s, 1H), 5.73 (s, 1H), 5.07 (s, 1H), 2.08 (s, 3H). 13C NMR
(100 MHz, CDCl3) δ 169.2, 139.6, 137.0, 131.7, 127.6, 122.6,
103.7, 24.3.
N‐[1‐(3,4‐Dimethylphenyl)vinyl]acetamide (3h). 1H NMR
(400 MHz, CDCl3) δ 7.18–7.10 (m, 4H), 5.77 (s, 1H), 5.04 (s, 1H),
2.27 (s, 3H), 2.26 (s, 3H), 2.08 (s, 3H). 13C NMR (100 MHz,
CDCl3) δ 169.2, 140.5, 137.2, 136.8, 135.9, 129.8, 127.2, 123.4,
101.6, 24.4, 19.8, 19.5. HRMS Calcd (ESI) m/z for C12H15NNaO:
[M + Na]+ 212.1046, found: 212.1050.
Scheme 1. [Pd/Cu]‐catalyzed synthesis of enamides and 1,3‐diynes.
purchased from commercial suppliers and used without fur‐
ther purification. 1H and 13C NMR spectra were recorded using
Varian instruments at 400 and 100 MHz, respectively, with
tetramethylsilane as an internal standard. All products were
isolated using short chromatography on a silica‐gel (200–300
mesh) column, with petroleum ether (60–90 °C) and EtOAc as
the eluent, unless otherwise stated. Compounds that had pre‐
viously been described in the literature were characterized by
comparison of their 1H NMR and 13C NMR spectra with the re‐
ported data template.
2.2. General procedure for synthesis of enamide 3a and
1,3‐diyne 4a
N‐[1‐(5,6,7,8‐Tetrahydronaphthalen‐2‐yl)vinyl]acetamide
(3i). 1H NMR (400 MHz, CDCl3) δ 7.14–7.11 (m, 2H), 7.06 (d, J =
8.0 Hz, 1H), 6.87 (s, 1H), 5.82 (s, 1H), 5.03 (s, 1H), 2.77 (s, 4H),
2.12 (s, 3H), 1.80 (s, 4H). 13C NMR (100 MHz, CDCl3) δ 169.0,
140.5, 137.9, 137.4, 135.6, 129.4, 126.5, 123.1, 101.4, 29.4, 29.1,
24.6, 23.0. HRMS Calcd (ESI) m/z for C14H17NNaO: [M + Na]+
238.1202, found: 238.1207.
N‐[1‐(2,5‐Dimethylphenyl)vinyl]acetamide (3j). 1H NMR
(400 MHz, CDCl3) δ 7.16 (s, 1H), 7.09–7.06 (m, 3H), 5.97 (s, 1H),
4.65 (s, 1H), 2.32 (s, 3H), 2.29 (s, 3H), 1.93 (s, 3H).13C NMR (100
MHz, CDCl3) δ 169.0, 140.7, 138.4, 135.3, 132.6, 130.3, 129.8,
129.1, 102.1, 24.2, 20.8, 19.1. HRMS Calcd (ESI) m/z for
C12H16NO: [M + H]+ 190.1226, found: 190.1227.
N‐[1‐(3‐Methoxyphenyl)vinyl]acetamide (3k). 1H NMR (400
MHz, CDCl3) δ 7.28–7.24 (m, 2H), 6.98 (d, J = 7.2 Hz, 1H), 6.93
(s, 1H), 6.86 (d, J = 8.0 Hz, 1H), 5.80 (s, 1H), 5.07 (s, 1H), 3.80 (s,
3H), 2.05 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 169.3, 159.6,
140.4, 139.8, 129.6, 118.4, 113.8, 112.0, 102.6, 55.3, 24.4.
N‐[1‐(Naphthalen‐2‐yl)vinyl]acetamide (3l). 1H NMR (400
MHz, CDCl3) δ 7.84–7.82 (m, 4H), 7.54–7.49 (m, 3H), 7.08 (s,
1H), 5.92 (s, 1H), 5.24 (s, 1H), 2.14 (s, 3H). 13C NMR (100 MHz,
CDCl3) δ 169.2, 140.4, 135.5, 133.2, 133.0, 128.4, 128.1, 127.6,
126.5, 126.4, 124.7, 124.0, 103.4, 24.4.
(E)‐N‐(1‐Phenylprop‐1‐en‐1‐yl)acetamide (3m). 1H NMR
(400 MHz, DMSO‐d6) δ 9.11 (s, 1H), 7.36–7.22 (m, 5H),
5.89–5.87 (m, 1H), 1.99 (s, 3H), 1.64 (d, J = 6.4 Hz, 3H). 13C NMR
(100 MHz, DMSO‐d6) δ 167.8, 138.4, 134.7, 128.2, 127.2, 125.1,
119.3, 22.7, 13.8.
A 25 mL round‐bottomed flask charged with ketoxime 1a
(67.5 mg, 0.5 mmol), phenylacetylene 2a (102.0 mg, 1.0 mmol),
acetic anhydride (102.0 mg, 1.0 mmol), pyridine (47.4 mg, 0.6
mmol), CuI (9.5 mg, 10 mol%), and Pd(PPh3)2Cl2 (0.7 mg, 0.2
mol%) in 1,2‐dichloroethane (5.0 mL) was stirred at 120 °C for
5 h under Ar. After completion of the reaction (detected using
thin‐layer chromatography), the reaction mixture was cooled
to room temperature, diluted with EtOAc (10 mL), and washed
with H2O (10 mL), brine (10 mL), and CuSO4 (2 mol/L, 5 mL).
The organic layers were dried over anhydrous Na2SO4 and
evaporated in vacuo. The residue was purified by chromatog‐
raphy on silica gel to afford enamide 3a (77.3 mg, 96% yield)
and 1,3‐diyne 4a (82.8 mg, 82% yield).
2.3. Analytical data for enamides 3 and 1,3‐diynes 4
N‐(1‐Phenylvinyl)acetamide (3a). 1H NMR (400 MHz, CDCl3)
δ 7.39–7.34 (m, 6H), 5.78 (s, 1H), 5.07 (s, 1H), 2.04 (s, 3H). 13
C
NMR (100 MHz, CDCl3) δ 169.4, 140.5, 138.2, 128.5, 126.0,
102.6, 24.3.
N‐[1‐(p‐Tolyl)vinyl]acetamide (3b). 1H NMR (400 MHz,
CDCl3) δ 7.30 (d, J = 7.2 Hz, 2H), 7.16 (d, J = 8.0 Hz, 2H), 7.10 (s,
1H), 5.77 (s, 1H), 5.04 (s, 1H), 2.35 (s, 3H), 2.07 (s, 3H). 13C NMR
(100 MHz, CDCl3) δ 169.2, 140.4, 138.5, 135.5, 129.3, 125.9,
101.9, 24.4, 21.1.
N‐[1‐(4‐Methoxyphenyl)vinyl]acetamide (3c). 1H NMR (400
MHz, CDCl3) δ 7.33 (d, J = 8.0 Hz, 2H), 7.17 (s, 1H), 6.86 (d, J =
8.8 Hz, 2H), 5.69 (s, 1H), 4.99 (s, 1H), 3.79 (s, 3H), 2.06 (s, 3H).
13C NMR (100 MHz, CDCl3) δ 169.3, 159.8, 140.1, 130.8, 127.3,
113.9, 101.5, 55.3, 24.4.
N‐(2‐Methyl‐1‐phenylprop‐1‐en‐1‐yl)acetamide (3n). 1H
NMR (400 MHz, DMSO‐d6) δ 9.02 (s, 1H), 7.30–7.21 (m, 5H),
1.87 (s, 3H), 1.70 (s, 3H), 1.68 (s, 3H). 13C NMR (100 MHz,
DMSO‐d6) δ 167.5, 139.1, 128.8, 127.7, 127.3, 126.7, 22.7, 20.7,
20.7.
N‐[1‐(4‐Nitrophenyl)vinyl]acetamide (3d). 1H NMR (400
MHz, CDCl3) δ 8.19 (d, J = 8.4 Hz, 2H), 7.57 (d, J = 8.0 Hz, 2H),
7.15 (s, 1H), 5.79 (s, 1H), 5.25 (s, 1H), 2.14 (s, 3H). 13C NMR
N‐(1‐Phenylvinyl)propionamide (3o). 1H NMR (400 MHz,