S. N. Aslam et al. / Tetrahedron 62 (2006) 4214–4226
4221
197(21), 182(16), 165(64), 153(27), 139(13), 121(20),
104(21), 91(20), 76(13), 63(10), 51(10).27
chromatography and stilbene 8i was obtained as yellow
solid in 68% yield (810 mg), mp 137–139 8C; IR (CHCl3)
nmax: 3680, 3300, 3000, 2890, 1625, 1600, 1590, 1400,
1485, 1430, 1320, 1290, 1260, 1170, 1160, 1040, 1015,975,
940, 870, 840 cmK1; 1H NMR (CDCl3): d 7.51 (dd, JZ7.7,
1.5 Hz, 1H), 7.40 (d, JZ16.6 Hz, 1H), 7.14 (d, JZ16.6 Hz,
1H), 7.13–7.08 (m, 2H), 6.94–6.89 (m, 1H), 6.79 (d, JZ
7.2 Hz, 1H), 6.53 (s, 1H), 5.93 (s, 2H), 5.15 (br s, 1H), 3.80
(s, 3H); 13C NMR (CDCl3): d 152.8, 152.7, 147.7, 141.8,
128.2, 127.1, 125.4, 124.6, 121.0, 121.0, 119.6, 115.8,
105.3, 101.3, 95.0, 56.8; MS m/z (% relative intensity, ion):
270(100, [M]C), 255(5), 227(40), 197(20), 181(50),
169(20), 152(15), 133(20), 115(20), 105(5), 91(10),
77(10), 63(10), 53(2); HRMS (EI) m/z 271.0965 [MC
H]C, calcd for C16H15O4 271.0970.
4.5.5. 1-(3,4-Methylenedioxyphenyl)-2-phenylethene
(8e). IR (CHCl3) nmax: 2900, 1605, 1495, 1450, 1360,
1255, 1100, 1040, 960, 935, 870, 610 cmK1 1H NMR
;
(CDCl3): d 7.46 (dt, JZ7.2, 1.5 Hz; 2H), 7.33 (tt, JZ7.2,
1.5 Hz, 2H), 7.22 (tt, JZ7.2, 1.5 Hz, 1H), 7.05 (d, JZ
1.5 Hz, 1H), 7.01 (d, JZ16.3 Hz, 1H), 6.92 (dd, JZ8.5,
1.5 Hz, 1H), 6.91 (d, JZ16.3 Hz, 1H), 6.78 (d, JZ8.5 Hz,
1H), 5.93 (s, 2H); 13C NMR (CDCl3): d 148.2, 147.3, 137.4,
131.9, 128.7, 128.4, 127.4, 127.0, 126.3, 121.5, 108.4,
105.6, 101.1; MS m/z (% relative intensity, ion): m/z
224(100, [M]C), 193(15), 165(85), 139(13), 115(10),
82(10), 63(10).29
4.5.6. 1-(3,4-Methylenedioxyphenyl)-2-(2-hydroxyphe-
nyl)ethene (8f). 1H NMR (CDCl3): d 7.94 (dd, JZ8.2,
1.5 Hz, 1H,), 7.23 (d, JZ8.2 Hz, 1H), 7.16–7.05 (m, 3H),
6.99–6.90 (m, 2H), 6.79 (d, JZ8.2 Hz, 2H), 5.96 (s, 2H),
1.70 (s, 1H); 13C NMR (CDCl3): d 152.9, 148.1, 147.3,
132.2, 129.8, 128.4, 127.1, 124.8, 121.5, 121.3, 121.1,
115.9, 108.4, 105.7, 101.1; MS m/z (% relative intensity,
ion): 240(100 [M]C), 225(5), 211(7), 193(7), 181(36),
165(18), 152(38), 139(5), 122(7), 105(3), 91(15), 76(16),
63(13), 51(7), 40(1); HRMS (EI) m/z: 240.0852 [M]C
(C15H12O3 requires 240.0786).
4.5.10. 1-(2-Methyl-4,5-methylenedioxyphenyl)-2-(2-
hydroxyphenyl)ethene (8j). To a stirred solution of
2-iodophenol (7b) (6.6 g, 30 mmol) in triethylamine
(50 mL) was added styrene 6c (3.42 g, 21 mmol), palladium
acetate (31 mg, 0.13 mmol) and tri-o-tolylphosphine
(85 mg, 0.27 mmol). The reaction mixture was stirred for
1 h at room temperature and then the temperature increased
to 100 8C. After 4 h of heating, a further equivalent of
2-iodophenol (7b) was added and stirring continued for
16 h. The reaction was monitored by following the
disappearance of styrene (6d) by TLC and GC. After
completion, the reaction was quenched by adding water
(50 mL) and extracted with ethyl acetate (1!50 mL) and
diethyl ether (3!50 mL). The organic extracts were dried
(MgSO4) and concentrated under reduced pressure. The
crude product was then purified by flash chromatography
and stilbene 8j was obtained as a white solid (2.77 g, 54%),
mp 147–149 8C; IR (CHCl3) nmax: 3600, 3300, 3000, 2890,
1610, 1505, 1485, 1460, 1370, 1320, 1255, 1170, 1045, 970,
4.5.7. 1-(3,4-Methylenedioxyphenyl)-2-(2-acetoxyphe-
nyl)ethene (8g). White solid, mp 68–70 8C; IR (nujol
mull) nmax: 1701, 1581, 1460, 1442, 1333, 1210, 1187,
1175,1135, 1045, 1001, 982 cmK1; MS m/z (% relative
intensity, ion): 282(51, [M]C), 265(1), 240(100), 211(4),
181(24), 152(37), 131(53), 103(4), 86(1), 63(20).
940, 875 cmK1 1H NMR (CDCl3): d 7.48 (dd, JZ7.9,
;
4.5.8. 1-(3,4-Methylenedioxyphenyl)-2-(4-methoxyphe-
nyl)ethene (8h). White solid, mp 139–141 8C; IR (CHCl3)
nmax: 2900, 2840, 1610, 1510, 1590, 1450, 1360, 1310,
1285, 1255, 1180, 1040, 960, 935, 850, 825, 610 cmK1; 1H
NMR (CDCl3): d 7.41 (dt, JZ8.9, 2.0 Hz, 2H), 7.03 (d, JZ
1.5 Hz, 1H), 6.92–6.82 (m, 5H), 6.81 (d, JZ8.2 Hz, 1H),
5.94 (s, 2H), 3.81 (s, 3H); 13C NMR (CDCl3): d 159.2,
148.3, 147.2, 132.4, 130.2, 127.5, 126.6, 126.3, 121.0,
114.1, 108.4, 105.4, 101.1, 55.3; MS m/z (% relative
intensity, ion): 254(100, [M]C), 223(5), 181(20), 152(50),
127(50), 98(10), 76(10), 51(10).30
1.7 Hz, 1H), 7.26 (d, JZ16.3 Hz, 1H), 7.13 (td, JZ7.9, 1.7,
1H), 7.12 (s, 1H), 7.08 (d, JZ16.3 Hz, 1H), 6.94 (td, JZ7.9,
0.7 Hz, 1H), 6.81 (dd, JZ7.9, 1.5 Hz, 1H), 6.66 (s, 1H),
5.94 (s, 2H), 2.33 (s, 3H), 1.58 (br s, 1H,); 13C NMR
(CDCl3): d 152.9, 146.9, 130.9, 129.9, 129.9, 128.4, 127.9,
127.3, 125.1, 122.4, 121.1, 115.9, 110.4, 105.2, 100.9,
19.8; MS m/z (% relative intensity, ion): 254(100, [M]C),
239(27), 225(7), 209(8), 195(13), 181(15), 165(27),
152(33), 135(13), 115(13), 102(8), 89(15), 77(13), 63(12),
51(14), 40(5); HRMS (EI) m/z 254.0937 [M]C, calcd for
C16H14O3 254.0943.
4.5.9. 1-(2-Methoxy-4,5-methylenedioxyphenyl)-2-(2-
hydroxyphenyl)ethene (8i). To a stirred solution of
2-iodophenol (7b) (0.99 g, 4.5 mmol) in triethylamine
(10 mL) was added styrene 6b (0.8 g, 4.5 mmol), palladium
acetate (28 mg, 0.12 mmol) and tri-o-tolylphosphine
(80 mg, 0.26 mmol). The reaction mixture was stirred at
room temperature for 1 h and then the temperature was
increased to 100 8C. After 4 h of heating, a further
equivalent of 7b (0.99 g, 4.5 mmol) was added and stirring
was continued for a further 16 h. The reaction was
monitored by following the disappearance of styrene 6b
by TLC and GC. On completion, the reaction was quenched
by addition of water (50 mL) and extracted with ethyl
acetate (50 mL) and diethyl ether (3!50 mL). The organic
extracts were dried (MgSO4) and concentrated under
reduced pressure. The crude product was purified by flash
4.6. Epoxidation and acid-catalysed cyclisation of
stilbenes
4.6.1. 1-(2-Methoxy-4,5-methylenedioxyphenyl)-2-(2-
hydroxyphenyl)ethene oxide (9a). 3-Chloroperbenzoic
acid (276 mg, 2 equiv) was added stepwise to a stirred
solution of stilbene 8i (220 mg, 0.8 mmol) in DCM (10 mL)
at 0 8C. After addition, the reaction mixture was warmed to
35 8C and stirring continued for 2 h. The reaction was
quenched by the addition of water (50 mL) and extracted
with DCM. The combined organic extracts were dried and
concentrated under vacuum and purified by flash chroma-
tography. The epoxide 9a was obtained as a yellow solid
(150 mg, 67%), mp 118–122 8C; IR (CHCl3) nmax: 3520,
3080, 2900, 1580, 1490, 1430, 1280, 1260, 1170, 1080,