The Journal of Organic Chemistry
NOTE
134.3 (C), 136.3 (CH); MS m/z (rel intensity) 368 (M+, 8), 289 (100),
162 (48), 109 (52); HRMS [M]+ for C10H10BrIS 367.8731, found
367.8740.
(CH Â 2), 129.9 (CH Â 2), 130.2 (C), 156.2 (C), 209.4 (C). These data
are in agreement with those reported in the literature.18
1-Bromo-3-(buta-2,3-dienyloxy)benzene (2e): oil; TLC
1
(EtOAc/hexanes (1:10)) Rf = 0.67; H NMR (300 MHz, CDCl3) δ
(Z)-1-(4-Bromo-3-iodobut-2-enyloxy)-4-nitrobenzene (1q):
55%; white solid, mp 88À89 °C; TLC (EtOAc/hexanes (1:5)) Rf =
0.30; 1H NMR (300 MHz, CDCl3) δ 4.34 (s, 2 H), 4.68 (d, J = 5.1 Hz, 2
H), 6.40 (t, J = 5.1 Hz, 1 H), 6.92 (d, J = 8.1 Hz, 2 H), 8.18 (d, J = 8.1 Hz,
2 H); 13C NMR (75 MHz, CDCl3) δ 41.3 (CH2), 72.6 (CH2), 103.1
(C), 114.7 (CH Â 2), 126.0 (CH Â 2), 134.6 (CH), 141.9 (C), 162.9
(C); MS m/z (rel intensity) 397 (M+, 0.3), 318 (35), 261 (92), 259
(100); HRMS [M]+ for C10H9BrINO3 396.8810, found 396.8815.
(Z)-(4-Chloro-3-iodobut-2-enyloxy)benzene (1r): 73%; oil;
TLC (Et2O/hexanes (1:10)) Rf = 0.85; 1H NMR (300 MHz, CDCl3)
δ 4.37 (s, 2 H), 4.63 (d, J = 5.1 Hz, 2 H), 6.45 (t, J = 5.1 Hz, 1 H), 6.91
(d, J = 8.1 Hz, 2 H), 6.99 (t, J = 8.1 Hz, 1 H), 7.32 (dd, J = 8.1, 2.1 Hz, 2
H); 13C NMR (75 MHz, CDCl3) δ 53.4 (CH2), 71.6 (CH2), 101.3 (C),
114.6 (CH Â 2), 121.2 (CH), 129.6 (CH Â 2), 135.5 (CH), 158.0 (C);
MS m/z (rel intensity) 308 (M+, 7), 215 (8), 181 (9), 94 (100); HRMS
[M]+ for C10H10ClIO 307.9465, found 307.9460.
4.53 (dt, J = 6.6, 2.4 Hz, 2 H), 4.88 (dt, J = 6.6, 2.4 Hz, 2 H), 5.36 (quin,
J = 6.6 Hz, 1 H), 6.82À6.86 (m, 1 H), 7.06À7.15 (m, 3 H); 13C NMR
(75 MHz, CDCl3) δ 65.9 (CH2), 76.7 (CH2), 86.6 (CH), 113.8 (CH),
118.1 (CH), 122.7 (C), 123.9 (CH), 130.4 (CH), 159.0 (C), 209.5 (C);
MS m/z (rel intensity) 224 (M+, 8), 226 (7), 174 (100), 145 (76);
HRMS [M]+ for C10H9BrO 223.9837, found 223.9830.
2,4-Dibromo-1-(buta-2,3-dienyloxy)benzene (2f): oil; TLC
(EtOAc/hexanes (1:10)) Rf = 0.60; 1H NMR (300 MHz, CDCl3) δ 4.60
(dt, J = 6.6, 2.4 Hz, 2 H), 4.85 (dt, J = 6.6, 2.4 Hz, 2 H), 5.36 (quin, J = 6.6
Hz, 1 H), 6.76 (d, J = 8.7 Hz, 1 H), 7.33 (dd, J = 8.7, 2.4 Hz, 1 H), 7.64 (d,
J = 2.4 Hz, 1 H); 13C NMR (75 MHz, CDCl3) δ 67.1 (CH2), 76.9
(CH2), 86.4 (CH), 113.2 (C Â 2), 115.0 (CH), 131.0 (CH), 135.4
(CH), 154.0 (C), 209.4 (C); MS m/z (rel intensity) 302 (M+, 1), 304
(2), 252 (100), 250 (50); HRMS [M]+ for C10H8Br2O 301.8942, found
301.8948.
1-(Buta-2,3-dienyloxy)-2-iodobenzene(2g):oil;TLC(EtOAc/
hexanes (1:10)) Rf = 0.55; 1H NMR (300 MHz, CDCl3) δ 4.60À4.64 (m,
2 H), 4.84À4.88 (m, 2 H), 5.40 (quin, J = 6.6 Hz, 1 H), 6.67À6.72 (m, 1
H), 6.82 (dd, J = 8.1, 1.2 Hz, 1 H), 7.23À7.29 (m, 1 H), 7.75 (dd, J = 7.8,
1.5 Hz, 1 H); 13C NMR (75 MHz, CDCl3) δ 66.6 (CH2), 76.6 (CH2),
86.6 (CH), 86.7 (C), 112.5 (CH), 122.5 (CH), 129.0 (CH), 139.2 (CH),
156.5 (C), 208.9 (C). These data are in agreement with those reported in
the literature.19
3-(Buta-2,3-dienyloxy)benzonitrile (2h): oil; TLC (Et2O/
hexanes (1:10)) Rf = 0.38; 1H NMR (300 MHz, CDCl3) δ 4.55À4.59
(m, 2 H), 4.86À4.90 (m, 2 H), 5.29À5.38 (m, 1 H), 7.10À7.14 (m, 2
H), 7.21À7.24 (m, 1 H), 7.32À7.37 (m, 1 H); 13C NMR (75 MHz,
CDCl3) δ 66.0 (CH2), 76.9 (CH2), 86.3 (CH), 113.0 (C), 117.9 (CH),
118.6 (C), 120.1 (CH), 124.6 (CH), 130.2 (CH), 158.3 (C), 209.5 (C);
MS m/z (rel intensity) 171 (M+, 8), 156 (15), 119 (100), 91 (9); HRMS
[M]+ for C11H9NO 171.0684, found 171.0689.
2-(Buta-2,3-dienyloxy)benzaldehyde (2i): oil; TLC (EtOAc/
hexanes (1:11)) Rf = 0.30; 1H NMR (300 MHz, CDCl3) δ 4.65 (dt, J =
6.6, 2.7 Hz, 2 H), 4.87 (dt, J = 6.6, 2.7 Hz, 2 H), 5.38 (quin,
J = 6.6 Hz, 1 H), 6.95À7.02 (m, 2 H), 7.47À7.53 (m, 1 H), 7.80 (dd,
J = 7.8, 1.5 Hz, 1 H), 10.47 (d, J = 0.9 Hz, 1 H); 13C NMR (75 MHz,
CDCl3) δ 66.1 (CH2), 77.0 (CH2), 86.5 (CH), 112.9 (CH), 120.9
(CH), 125.1 (C), 128.3 (CH), 135.7 (CH), 160.7 (C), 189.8 (CH),
209.4 (C). These data are in agreement with those reported in the
literature.20
Methyl 2-(buta-2,3-dienyloxy)benzoate (2j): oil; TLC (EtOAc/
hexanes (1:10)) Rf = 0.25; 1H NMR (300 MHz, CDCl3) δ 3.86 (s, 3 H),
4.63À4.67 (m, 2 H), 4.82À4.86 (m, 2 H), 5.35À5.44 (m, 1 H), 6.94À6.99
(m, 2 H), 7.39À7.42 (m, 1 H), 7.72À7.80 (m, 1 H); 13C NMR (75 MHz,
CDCl3) δ 51.8 (CH3), 66.8 (CH2), 76.5 (CH2), 86.9 (CH), 114.0 (CH),
120.4 (CH), 120.8 (C), 131.5 (CH), 133.1 (CH), 157.7 (C), 166.6 (C),
209.2 (C); MS m/z (rel intensity) 204 (M+, 2), 152 (31), 120 (100), 92
(26); HRMS [M]+ for C12H12O3 204.0786, found 204.0781.
(Z)-(3,4-Dibromobut-2-enyloxy)benzene (1s): 75%; oil; TLC
(Et2O/hexanes (1:10)) Rf = 0.65; 1H NMR (300 MHz, CDCl3) δ 4.24
(s, 2 H), 4.67 (d, J = 5.1 Hz, 2 H), 6.44 (t, J = 5.1 Hz, 1 H), 6.87 (d, J = 8.4
Hz, 2 H), 6.96 (t, J = 8.4 Hz, 1 H), 7.26À7.31 (m, 2 H); 13C NMR (75
MHz, CDCl3) δ 37.3 (CH2), 67.3 (CH2), 114.6 (CH Â 2), 121.2 (CH),
123.5 (C), 129.6 (CH Â 2), 130.5 (CH), 157.9 (C); MS m/z (rel
intensity) 304 (M+, 1), 259 (2), 225 (23), 94 (100); HRMS [M]+ for
C10H10Br2O 303.9098, found 303.9104.
General Procedure for Indium- or Zinc-Mediated Dehalo-
genation Reactions in an Aqueous Solvent to Form Allenes.
A mixture of iodoallyl bromide substrate 1 (1.5 mmol), indium powder
(325 mesh, 1.5 mmol), or zinc dust (325 mesh, 1.5 mmol) in THF
(1.6 mL) and water (0.4 mL) was stirred at room temperature overnight.
Water (2.0 mL) was added to the mixture, which was then extracted with
Et2O (3 Â 5.0 mL). The combined organic layers were dried over
MgSO4 and concentrated in vacuo, giving a residue which was subjected
to silica gel chromatography to furnish the pure product 2 (hexanes).
(Buta-2,3-dienyloxy)benzene (2a): oil; TLC (EtOAc/hexanes
(1:10)) Rf = 0.63; 1H NMR (300 MHz, CDCl3) δ 4.56 (dt, J = 6.9, 2.4
Hz, 2 H), 4.84 (dt, J = 6.9, 2.4 Hz, 2 H), 5.38 (quin, J = 6.9 Hz, 1 H),
6.89À6.97 (m, 3 H), 7.24À7.30 (m, 2 H); 13C NMR (75 MHz, CDCl3)
δ 65.6 (CH2), 76.4 (CH2), 87.0 (CH), 114.7 (CH Â 2), 120.8 (CH),
129.3 (CH Â 2), 158.2 (C), 209.3 (C). These data are in agreement with
those reported in the literature.4b
1-(Buta-2,3-dienyloxy)-4-chlorobenzene (2b): oil; TLC
1
(EtOAc/hexanes (1:2)) Rf = 0.63; H NMR (300 MHz, CDCl3) δ
4.52 (dt, J = 6.9, 2.4 Hz, 2 H), 4.85 (dt, J = 6.9, 2.4 Hz, 2 H), 5.34 (quin,
J = 6.9 Hz, 1 H), 6.79À6.85 (m, 2 H), 7.18À7.24 (m, 2 H); 13C NMR
(75 MHz, CDCl3) δ 66.1 (CH2), 76.6 (CH2), 86.8 (CH), 116.2 (CH Â
2), 125.8 (C), 129.3 (CH Â 2), 156.9 (C), 209.4 (C). These data are in
agreement with those reported in the literature.18
1-(Buta-2,3-dienyloxy)-4-methoxybenzene (2c): white so-
lid; mp 43À44 °C (hexanes); TLC (EtOAc/hexanes (1:10)) Rf = 0.58;
1H NMR (300 MHz, CDCl3) δ 3.75 (s, 3 H), 4.50 (dt, J = 6.6, 2.7 Hz, 2
H), 4.84 (dt, J = 6.6, 2.7 Hz, 2 H), 5.37 (quin, J = 6.6 Hz, 1 H), 6.80À6.88
(m, 4 H); 13C NMR (75 MHz, CDCl3) δ 55.6 (CH3), 66.5 (CH2), 76.3
(CH2), 87.3 (CH), 114.6 (CH Â 2), 115.9 (CH Â 2), 152.4 (C), 154.0
(C), 209.3 (C). These data are in agreement with those reported in the
literature.18
N-(2-(Buta-2,3-dienyloxy)phenyl)acetamide (2k): white so-
lid; mp 58À59 °C (hexanes); TLC (EtOAc/hexanes (1:10)) Rf = 0.25;
1H NMR (300 MHz, CDCl3) δ 2.15 (s, 3 H), 4.55À4.59 (m, 2 H),
4.86À4.90 (m, 2 H), 5.34À5.39 (m, 1 H), 6.82À6.98 (m, 3 H), 7.80 (br
s, 1 H), 8.32 (d, J = 7.5 Hz, 1 H); 13C NMR (75 MHz, CDCl3) δ 24.9
(CH3), 66.0 (CH2), 76.9 (CH2), 86.9 (CH), 111.4 (CH), 120.0 (CH),
121.4 (CH), 123.4 (CH), 128.1 (C), 146.4 (C), 168.1 (C), 209.4 (C);
MS m/z (rel intensity) 203 (M+, 8), 161 (15), 134 (19), 109 (100);
HRMS [M]+ for C12H13NO2 203.0946, found 203.0949.
1-(Buta-2,3-dienyloxy)-4-methylbenzene (2d): oil; TLC
1
(EtOAc/hexanes (1:10)) Rf = 0.56; H NMR (300 MHz, CDCl3) δ
2.32 (s, 3 H), 4.51À4.55 (m, 2 H), 4.82À4.86 (m, 2 H), 5.33À5.42 (m,
1 H), 6.79À6.83 (m, 2 H), 7.05À7.24 (m, 2 H); 13C NMR (75 MHz,
CDCl3) δ 20.5 (CH3), 65.9 (CH2), 76.4 (CH2), 87.2 (CH), 114.7
Buta-2,3-dienyl benzoate (2l): oil; TLC (EtOAc/hexanes
1
(1:10)) Rf = 0.53; H NMR (300 MHz, CDCl3) δ 4.79À4.88 (m, 4
H), 5.40 (quin, J = 6.6 Hz, 1 H), 7.39À7.44 (m, 2 H), 7.51À7.57
8522
dx.doi.org/10.1021/jo2015104 |J. Org. Chem. 2011, 76, 8518–8523