Iodine-Promoted Oxidative Conversion of o-Vinyl Diaryl Ketones
temperature and then stirred for 1.5 h. The reaction mixture was
quenched with a saturated NH4Cl solution, and the resulting solu-
tion was extracted with ethyl acetate. The organic layer was dried
with anhydrous Na2SO4. Evaporation of solvent and then purifica-
tion of residue on neutral alumina by column chromatography gave
ortho-vinyl-substituted Weinreb amide 10 (1.16 g, 92%) as a color-
[4-(Methylthio)phenyl](2-vinylphenyl)methanone (11e): Light yellow
gum (78% yield). IR (CHCl ): νmax = 1092, 1435, 1590, 1654, 2255,
˜
3
2925, 2985, 3057 cm–1. H NMR (400 MHz, CDCl3): δ = 2.50 (s,
1
3 H, -SMe), 5.21 (dd, J = 1.0 Hz, J = 1.0 Hz, 1 H, ArCHCH2),
5.69 (dd, J = 11.2 Hz, J = 17.6 Hz, 1 H, ArCHCH2), 6.73 (dd, J
= 11.2 Hz, J = 17.6 Hz, 1 H, -CH), 7.21–7.25 (m, 2 H, Ar), 7.30–
7.33 (m, 2 H, Ar), 7.43–7.50 (m, 1 H, Ar), 7.66 (d, J = 7.6 Hz, 1
H, Ar), 7.69–7.33 (m, 2 H, Ar) ppm. 13C NMR (100 MHz, CDCl3):
δ = 14.8, 116.6, 124.9, 125.9, 127.3, 128.3, 130.3, 130.7, 133.8,
134.2, 136.5, 138.5, 138.2, 146.6, 197.3 ppm. HRMS (ESI): calcd.
less liquid. IR (CHCl ): ν
= 1076, 1446, 1645, 2938 cm–1. 1H
˜
3
max
NMR (400 MHz, CDCl3): δ = 3.00–3.60 (br. s, 6 H, NCH3, OCH3),
5.26 (d, J = 11.2 Hz, 1 H, ArCHCH2), 5.68 (d, J = 17.2 Hz, 1 H,
ArCHCH2), 6.71 (dd, J = 11.2 Hz, J = 17.6 Hz, 1 H), 7.32–7.19
(m, 3 H), 7.52 (d, 1 H) ppm. 13C NMR (100 MHz, CDCl3): δ = for C16H15OS [M + H]+ 255.0844; found 255.0847.
32.1, 60.8, 111.7, 116.3, 122.0, 123.7, 125.0, 126.4, 129.2, 133.4,
Thiophen-2-yl(2-vinylphenyl)methanone (11f): Colorless gum (82%
134.4, 135.7, 172.1 ppm. HRMS (ESI): calcd. for C11H14NO2 [M
1
yield). IR (CHCl ): ν
= 1086, 1287, 1446, 1668, 2996 cm–1. H
˜
3
max
+ H]+ 192.1025; found 192.1034.
NMR (400 MHz, CDCl3): δ = 5.27 (d, J = 11.2 Hz, 1 H,
ArCHCH2), 5.73 (d, J = 17.6 Hz, 1 H, ArCHCH2), 6.86 (dd, J =
11.2 Hz, J = 17.6 Hz, 1 H, -CH), 7.10 (t, J = 4.8 Hz, 1 H, Ar), 7.34
(m, J = 7.2 Hz, 1 H, Ar), 7.41 (dd, J = 0.8 Hz, J = 4.0 Hz, 1 H,
Ar), 7.43–7.51 (m, 2 H, Ar), 7.68 (d, J = 8.0 Hz, 1 H, Ar), 7.73 (d,
J = 4.8 Hz, 1 H, Ar) ppm. 13C NMR (100 MHz, CDCl3): δ = 116.7,
126.1, 127.2, 128.2, 128.3, 130.6, 134.1, 135.3, 136.0, 136.4, 137.8,
145.0, 190.1 ppm. HRMS (ESI): calcd. for C13H10OSNa [M +
Na]+ 237.0350; found 237.0350.
General Procedure for the Addition of the Grignard Reagents to the
Weinreb Amide: To a solution of the aryl-, heteroaryl-, or alkylmag-
nesium bromide (3.0 mmol) in dry THF (4 mL) was added a solu-
tion of o-vinyl-substituted WA 10, 25, or 26 (1.0 mmol) in dry THF
(4 mL) at 0 °C under an inert atmosphere, and the resulting mixture
was stirred at room temperature for 3 h. Upon completion of the
reaction, the mixture was quenched by the cautious addition of a
saturated aqueous ammonium chloride solution. The aqueous layer
was extracted with ethyl acetate, and the organic layer was washed
with water and dried with Na2SO4. Evaporation of solvent and
then purification of residue on silica gel by column chromatog-
raphy (hexane/ethyl acetate) furnished the corresponding ketones.
The analytical and spectroscopic data for the products 4-tolyl(2-
vinylphenyl)methanone (11d) and phenyl(2-vinylphenyl)methanone
(11h) matched those from the literature.[13]
(4-Fluorophenyl)(2-vinylphenyl)methanone (11g): Cream color gum
(72% yield). IR (CHCl ): ν
= 1150, 1262, 1422, 1597, 1663,
˜
3
max
2986, 3054 cm–1. 1H NMR (400 MHz, CDCl3): δ = 5.23 (d, J =
10.8 Hz, 1 H, ArCHCH2), 5.70 (d, J = 17.6 Hz, 1 H, ArCHCH2),
6.73 (dd, J = 10.8 Hz, J = 17.6 Hz, 1 H, -CH), 7.10 (t, J = 8.4 Hz,
2 H, Ar), 7.30–7.37 (m, 2 H, Ar), 7.45–7.51 (m, 1 H, Ar), 7.67 (d,
J = 8.0 Hz, 1 H, Ar), 7.81 (dd, J = 5.6, J = 8.4 Hz, 2 H, Ar) ppm.
13C NMR (100 MHz, CDCl3): δ = 115.6, 115.8, 116.9, 126.1, 127.3,
(4-Methoxyphenyl)(2-vinylphenyl)methanone (11a): Brown liquid
1
= 1082, 1460, 1682, 2994 cm–1. H
128.4, 130.6, 133.0, 133.1, 134.2, 136.7, 137.8, 166.0 (d, JC,F
=
(67% yield). IR (CHCl ): ν
˜
3
max
255 Hz), 196.7 ppm. HRMS (ESI): calcd. for C15H12OF [M + H]+
227.0872; found 227.0870.
NMR (400 MHz, CDCl3): δ = 3.86 (s, 3 H, OMe), 5.21 (d, J =
10.8 Hz, 1 H, ArCHCH2), 5.70 (d, J = 17.2 Hz, 1 H, ArCHCH2),
6.73 (dd, J = 11.2 Hz, J = 17.6 Hz, 1 H, -CH), 6.91 (d, J = 8.8 Hz,
2 H, Ar), 7.30–7.38 (m, 2 H, Ar), 7.42–7.50 (m, 1 H, Ar), 7.66 (d,
J = 8.0 Hz, 1 H, Ar), 7.78 (d, J = 8.8 Hz, 2 H, Ar) ppm. 13C NMR
(100 MHz, CDCl3): δ = 55.6, 113.8, 116.4, 125.8, 127.2, 128.1,
130.0, 130.5, 132.8, 134.2, 136.2, 138.5, 163.9, 197.0 ppm. HRMS
(ESI): calcd. for C16H15O2[M + H]+ 239.1072; found 239.1078.
(4-Chlorophenyl)(2-vinylphenyl)methanone (11i): Colorless gum
(67% yield). IR (CHCl ): ν
= 1030, 1151, 1421, 1509, 1663,
˜
3
max
1686, 2936 cm–1. 1H NMR (400 MHz, CDCl3): δ = 4.35 (d, J =
11.2 Hz, 1 H, ArCHCH2), 4.81 (d, J = 17.6 Hz, 1 H, ArCHCH2),
5.85 (dd, J = 11.2 Hz, J = 17.6 Hz, 1 H, -CH), 6.40–6.47 (m, 2 H,
Ar), 6.52–6.55 (m, 2 H, Ar), 6.58–6.64 (m, 1 H), 6.61 (td, J =
2.0 Hz, J = 8.0 Hz, 1 H, Ar), 6.85 (d, J = 8.4 Hz, 2 H, Ar) ppm.
13C NMR (100 MHz, CDCl3): δ = 117.0, 126.2, 127.4, 128.5, 128.9,
130.7, 131.7, 134.2, 136.0, 136.8, 137.5, 140.0, 197.0 ppm. HRMS
(ESI): calcd. for C15H12OCl [M + H]+ 243.0577; found 243.0581.
(3,4-Dimethoxyphenyl)(2-vinylphenyl)methanone (11b): Brown color
gum (62% yield). IR (CHCl ): ν
= 1080, 1284, 1454, 1668,
˜
3
max
2986 cm–1. H NMR (500 MHz, CDCl3): δ = 3.91, 3.94 (2 s, 6 H,
2 OCH3), 5.20 (dd, J = 1.0 Hz, J = 11.0 Hz, 1 H, ArCHCH2), 5.68
(dd, J = 1.0 Hz, J = 17.5 Hz, 1 H, ArCHCH2), 6.72 (dd, J =
11.0 Hz, J = 17.5 Hz, 1 H, -CH), 6.78 (d, J = 8.5 Hz, 1 H, Ar),
7.06 (dd, J = 1.0 Hz, J = 7.5 Hz, 1 H, Ar), 7.40 (d, J = 7.0 Hz, 1
H, Ar), 7.53–7.63 (m, 3 H, Ar), 7.82 (d, J = 7.5 Hz, 1 H, Ar) ppm.
13C NMR (125 MHz, CDCl3): δ = 56.1, 56.2, 108.3, 112.1, 128.0,
128.5, 130.3, 130.4, 130.5, 131.1, 133.1, 134.4, 138.3, 148.2, 151.0,
197.5 ppm. HRMS (ESI): calcd. for C17H17O3 [M + H]+ 269.1178;
found 269.1166.
1
(3,4-Dichlorophenyl)(2-vinylphenyl)methanone (11j): Cream color
gum (60% yield). IR (CHCl ): νmax = 1031, 1266, 1462, 1668, 2927,
˜
3
3054 cm–1. 1H NMR (400 MHz, CDCl3): δ = 5.26 (dd, J = 0.8 Hz,
J = 11.2 Hz, 1 H, ArCHCH2), 5.69 (dd, J = 0.8 Hz, J = 17.2 Hz,
1 H, ArCHCH2), 6.73 (dd, J = 11.2 Hz, J = 17.6 Hz, 1 H, -CH),
7.31–7.39 (m, 2 H, Ar), 7.50–7.55 (m, 2 H, Ar), 7.60 (dd, J =
2.0 Hz, J = 8.4 Hz, 1 H, Ar), 7.67 (d, J = 8.0 Hz, 1 H, Ar), 7.88
(d, J = 2.0 Hz, 1 H, Ar) ppm. 13C NMR (100 MHz, CDCl3): δ =
115.6, 115.8, 116.9, 126.1, 127.3, 128.4, 130.6, 133.0, 133.1, 134.2,
136.7, 137.8, 164.7, 167.3, 196.7 ppm.
(3,4,5-Trimethoxyphenyl)(2-vinylphenyl)methanone (11c): Light
brown crystalline solid (72% yield); m.p. 120–122 °C, IR (CHCl3):
ν
= 1129, 1333, 1463, 1504, 1658, 2940 cm–1. 1H NMR
2-Vinylvalerophenone (11k): Yellow gum (15% yield). IR (CHCl3):
˜
max
(500 MHz, CDCl3): δ = 3.81 (s, 6 H, 2 OCH3), 3.92 (s, 3 H, OCH3),
5.23 (d, J = 11.5 Hz, 1 H, ArCHCH2), 5.71 (d, J = 17.5 Hz, 1 H,
ArCHCH2), 6.75 (dd, J = 11.0 Hz, J = 17.0 Hz, 1 H, -CH), 7.05
(s, 2 H, Ar), 7.32–7.36 (m, 2 H, Ar), 7.44–7.49 (m, 1 H, Ar), 7.67
(d, J = 8.0 Hz, 1 H, Ar) ppm. 13C NMR (125 MHz, CDCl3): δ =
56.3, 61.0, 108.0, 116.5, 125.9, 127.2, 128.4, 130.4, 132.6, 134.3,
136.6, 137.9, 143.0, 153.0, 197.1 ppm. HRMS (ESI): calcd. for
C18H18O4Na [M + Na]+ 321.1103; found 321.1091.
ν
= 1265, 1422, 1445, 1684, 2931, 2961, 3054 cm–1. 1H NMR
˜
max
(500 MHz, CDCl3): δ = 0.93 (t, 3 H, CH3), 1.35–1.43 (m, 2 H,
-CH2), 1.64–1.72 (m, 2 H, -CH2), 2.87 (t, J = 7.5 Hz, 2 H, -CH2),
5.32 (dd, J = 1.0 Hz, J = 11.0 Hz, 1 H, ArCHCH2), 5.64 (dd, J =
1.0 Hz, J = 17.5 Hz, 1 H, ArCHCH2), 7.08 (dd, J = 11.0 Hz, J =
17.5 Hz, 1 H, -CH), 7.33 (dt, J = 1.0 Hz, J = 8.0 Hz, 1 H, Ar),
7.43 (dt, J = 1.0 Hz, J = 7.5 Hz, 1 H, Ar), 7.53–7.59 (m, 2 H,
Ar) ppm. 13C NMR (125 MHz, CDCl3): δ = 14.0, 22.5, 26.6, 42.0,
Eur. J. Org. Chem. 2014, 1066–1075
© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
1071