7558
S. Clough et al. / Tetrahedron 61 (2005) 7554–7561
provided an analytical sample: IR (HATR) 2971, 2866,
1635, 1111, 1052, 990, and 808 cmK1; 1H NMR (300 MHz,
CDCl3) d 1.28 (t, JZ7.1 Hz, 6H), 2.36 (s, 3H), 3.70 (m, 4H),
5.50 (d, JZ6.7 Hz, 1H), 6.23 (d, JZ6.7 Hz, 1H), 7.18 (d,
JZ8.2 Hz, 2H), 7.53 (d, JZ8.2 Hz, 2H); 13C NMR
(125.8 MHz, CDCl3) d 15.3, 21.1, 61.6, 99.4, 123.8,
126.5, 129.0, 134.3, 135.9, 139.3; mass spec m/z 254
(MC,1), 219 (65), 211 (36), 209 (100), 183 (28), 181 (35),
165 (17), 163 (22), 145 (16), 117 (55), 115 (38), and 91 (12);
HRMS (EI, MC) calcd for C14H19ClO2 254.1074, found
254.1078.
using the procedure described for the synthesis of 4a:
Kugelrohr distillation afforded an analytical sample: bp
155–178 8C (1.3 mmHg); IR (HATR) 2945, 2843, 2776,
2735, 1660, and 1588 cmK1; 1H NMR (300 MHz, CDCl3) d
3.89 (s, 3H), 5.68 (d, JZ7.8 Hz, 1H), 7.44 (s, 4H), 9.46 (d,
JZ7.8 Hz, 1H); 13C NMR (75.5 MHz, CDCl3) d 56.7,
105.9, 128.8, 131.1, 131.6, 137.1, 176.3, 192.0 ppm; GC–
MS m/z 198 (12), 197 (37), 196 (MC, 37), 195 (100), 181
(4), 167 (5), 165 (9), 161 (28), 139 (23), 136 (28), 131 (19),
115 (23), 111 (17), 101 (23), 89 (20), 75 (34), 69 (95), 59
(29), and 51 (18); HRMS (EI, MC) calcd for C10H9O2Cl
196.0291, found 196.0292.
4.1.8. (Z)-3-Methoxy-3-phenyl-2-propenal (4a). 3-
Chloro-3-phenyl-2-propenal (1a) (0.200 g, 1.2 mmol) was
added to a solution of cesium carbonate (1.26 g, 3.9 mmol)
in 40 mL of methanol and the mixture was stirred at room
temperature for 40 h. The methanol was removed in vacuo
and the residue was taken up in ethyl acetate and washed
with water. After drying (MgSO4) the solvent was
evaporated to yield 0.18 g (92%) of 4a. Kugelrohr
distillation afforded an analytical sample: bp 170–175 8C
(0.7 mmHg); IR (HATR) 3058, 3017, 2940, 2843, 2776,
2735, 1655, 1588, 758, and 702 cmK1; 1H NMR (500 MHz,
CDCl3) d 3.79 (s, 3H), 5.61 (d, JZ7.8 Hz, 1H), 7.40 (m,
5H), 9.42 (d, JZ7.8 Hz, 1H); 13C NMR (125.8 MHz,
CDCl3) d 56.6, 105.6, 128.4, 129.6, 130.8, 177.6, 192.5;
GC–MS m/z 162 (MC, 29), 161 (100), 147 (3),131 (12),
115 (18), 102 (26), 91 (24), 77 (44), 69 (56) and 51 (18);
HRMS (EI, MC) calcd for C10H1002 162.0681, found
162.0674.
4.1.12. (E)-3-Methoxy-3-(30,40-methylenedioxyphenyl)-
2-propenal (4f). This compound was prepared from 1e in
78% yield using the procedure described for the synthesis of
4a: Kugelrohr distillation yielded an analytical sample as a
yellow solid: mp 72–74 8C; IR (HATR) 3075, 2991, 2919,
1
2848, 2771, 1655, and 1588 cmK1; H NMR (300 MHz,
CDCl3) d 3.86 (s, 3H), 5.62 (d, JZ7.7 Hz, 1H), 6.05 (s, 2H),
6.86 (d, JZ8.0 Hz, 1H), 6.98 (d, JZ1.6 Hz, 1H), 7.01 (dd,
JZ1.6, 8.0 Hz, 1H), 9.49 (d, JZ7.7 Hz, 1H); 13C NMR
(75.5 MHz, CDC13) d 56.6, 101.7, 105.4, 108.0, 109.5,
125.0, 126.0, 147.8, 150.0, 177.0, 192.5; GC–MS m/z 206
(MC, 75), 205 (73), 191 (8), 175 (25), 149 (27), 121 (16),
89 (19), 77 (21), and 69 (100); HRMS (EI, MC) calcd for
C11H1003 206.0580, found 206.0587.
4.1.13. (E)-3-Ethoxy-3-phenyl-2-propenal (5a). 3-Chloro-
3-phenyl-2-propenal (0.220 g, 1.2 mmol) was added to a
solution of cesium carbonate (1.26 g, 3.9 mmol) in 40 mL of
ethanol and the mixture was stirred at room temperature for
4.5 h. The ethanol was removed in vacuo and the residue
was taken up in ethyl acetate and washed with water. After
drying (MgSO4) the solvent was evaporated to yield 0.19 g
(90%) of 5a. Kugelrohr distillation afforded an analytical
sample: bp 157–167 8C (0.8 mmHg); IR (HATR) 3058,
2981, 2935, 2894, 2827, 2761, 2730, 1655, 1588, 758, and
4.1.9. (E)-3-Methoxy-3-(40-methylphenyl)-2-propenal
(4b). This compound was prepared from 1b in 95% yield
using the procedure described for the synthesis of 4a: mp
64–65 8C; IR (HATR) 2955, 2919, 2853, 2786, 2735, 1644,
and 1588 cmK1; 1H NMR (500 MHz, CDCl3) d 2.19 (s, 3H),
3.89 (s, 3H), 5.66 (d, JZ7.7 Hz, 1H), 7.27 (d, JZ8.0 Hz,
2H), 7.40 (d, JZ8.0 Hz, 2H), 9.49 (d, JZ7.7 Hz, 1H); 13C
NMR (125.8 MHz, CDCl3) d 21.3, 56.5, 105.4, 129.1,
129.7, 130.6, 141.4, 177.8, 192.9; GC–MS m/z 176 (MC,
36), 175 (100), 161 (95), 145 (9), 131 (13), 115 (48), 105
(9), 103 (11), 91 (43), 77 (14), 69 (56), 65 (19), and 51 (12);
HRMS (EI, MC) calcd for C11H12O2 176.0837, found
176.0833.
702 cmK1 1H NMR (300 MHz, CDCl3) d 1.47 (t, JZ
;
7.1 Hz, 3H), 4.09 (q, JZ7.1 Hz, 2H), 5.65 (d, JZ7.8 Hz,
1H), 7.47 (m, 5H), 9.45 (d, JZ7.8 Hz, 1H); 13C NMR
(75.5 MHz, CDCl3) d 14.1, 65.4, 106.1, 128.4, 129.8, 130.7,
133.5, 177.0, 192.9; GC–MS m/z 176 (MC, 21), 175 (38),
159 (3), 147 (40), 131 (29), 120 (4), 105 (34), 91 (24), 77
(70), 69 (100), 51 (46); HRMS (EI, MC) calcd for
C11H12O2 175.0837, found 176.0761.
4.1.10. (E)-3-Methoxy-3-(4-methoxyphenyl)-2-propenal
(4c). This compound was prepared from 1c in 78% yield
using the procedure described for the synthesis of 4a:
Kugelrohr distillation afforded an analytical sample: bp
185–195 8C (0.4 mmHg); IR (HATR) 3007, 2935, 2904,
4.1.14. (E)-3-Ethoxy-3-(p-tolyl)-2-propenal (5b). This
compound was prepared from 1b in 66% yield using the
procedure described for the synthesis of 5a: flash
chromatography (Biotage Horizon HFC instrument with a
#1542-2 silica cartridge and ethyl acetate/hexane as the
eluant) was used to produce an analytical sample, a yellow
solid: mp 60–61 8C; IR (HATR) 3274, 2986, 2913, 2835,
2769, 2727, 2357, 1654, 1588, 1344, 1212,1123, and
2838, 2771, 2735, 1650, and 1588 cmK1 1H NMR
;
(500 MHz, CDCl3) d 3.86 (s, 3H), 3.87 (s, 3H), 5.63 (d,
JZ7.7 Hz, 1H), 6.96 (d, JZ9.0 Hz, 2H), 7.45 (d, JZ
9.0 Hz, 2H), 9.49 (d, JZ7.7 Hz, 1H); 13C NMR
(125.8 MHz, CDCl3) d 55.4, 56.6, 105.0, 113.7, 125.6,
131.3, 161.9, 177.5, 192.6; GC–MS m/z 192 (MC, 52), 191
(100), 177 (19), 161 (53), 149 (8), 135 (36), 121 (12), 105
(10), 91 (25), 89 (27), 77 (36), 69 (69), 63 (28), and 51 (21);
HRMS (EI, MC) calcd for C11H1203 gives 192.0786, found
192.0780.
812 cmK1 1H NMR (500 MHz, CDCl3) d 1.46 (t, JZ
;
7.0 Hz, 3H), 2.41 (s, 3H), 4.08 (q, JZ7 Hz, 2H), 5.63 (d,
JZ7.8 Hz, 1H), 7.25 (d, JZ8.0 Hz, 2H), 7.40 (d, JZ
8.0 Hz, 2H), 9.47 (d, JZ7.8 Hz, 1H); 13C NMR
(125.8 MHz, CDCl3) d 14.2, 21.4, 65.4, 105.8, 129.0,
129.7, 130.7, 141.2, 177.1, 192.8; GC–MS m/z 190 (MC,
14), 189 (21), 175 (37), 161 (26), 147 (22), 131 (40), 119
4.1.11. (E)-3-(4-Chlorophenyl)-3-methoxy-2-propenal
(4d). This compound was prepared from 1d in 85% yield