N. Ortega et al. / Tetrahedron 68 (2012) 5185e5192
5191
ESI-MS: calculated [C15H14O2þNa]þ: 249.0886, found: 249.0884;
GCeMS: Rt (50_40): 9.3 min; EI: 153 (10), 165 (24), 211 (24), 225
(12), 226 (100), 227 (17); ATR-FTIR (cmꢁ1): 3049, 3016, 2971,
2910, 2845, 1609, 1514, 1477, 1455, 1328, 1301, 1283, 1247, 1228,
1187, 1173, 1102, 1027, 1012, 1102, 1027, 1012, 973, 926, 863, 824,
741, 712, 659, 625, 586; HPLC (AD-H, elute: hexane/i-PrOH¼99/1,
detector: 230 nm, flowrate: 0.5 mL/min), t1(minor)¼26.6 min,
t2(major)¼28.7 min.
1H), 5.73 (dd, J¼8.9, 8.9 Hz,1H), 3.82 (s, 3H), 3.59e3.53 (m, 1H), 3.21
(ddd, J¼15.9, 8.4, 1.1 Hz, 1H); 13C NMR (75 MHz, CDCl3): 159.7, 158.8,
156.5, 155.7, 155.6, 133.6, 128.2, 128.1, 127.4, 114.4, 114.2, 114.2, 112.2,
111.9,109.5,109.4, 84.7, 55.4, 38.6, 38.5; GCeMS: Rt (50_40): 9.2 min;
EI: 44 (36), 207 (40), 229 (17), 243 (10), 244 (100), 245 (16); ATR-FTIR
(cmꢁ1): 3019, 2968, 2904, 2842, 1611, 1583, 1512, 1475, 1438, 1355,
1305, 1288, 1247, 1223, 1180, 1123, 1031, 986, 922, 871, 812, 772, 744,
711, 638, 619, 577, 555, 518; HPLC (AD-H, elute: hexane/i-PrOH¼97/
3, detector: 230 nm, flowrate: 1.0 mL/min), t1(major)¼10.8 min,
t2(minor)¼11.3 min.
4.3.2.6. (S)-5-Methoxy-2-(4-methoxyphenyl)-2,3-dihydrobenzo-
furan: (þ)-Corsifuran A (3f). Following the general procedure, the
hydrogenation reaction was carried out for 16 h (in this case,
hydrogenation was performed at 60 bar (H2) and 40 ꢀC using 20%
catalyst loading). The product was obtained as white solid
4.3.2.10. (S)-5-Fluoro-2-phenyl-2,3-dihydrobenzofuran (3j). Follo-
wing the general procedure, the hydrogenation reaction was
carried out for 16 h (in this case, hydrogenation was performed at
60 bar (H2) and 40 ꢀC). The product was obtained as white solid
(61.5 mg, 0.24 mmol, 80% yield). 99:1 e.r. ½a D24
ꢃ ¼þ12.7 (c 0.55,
CHCl3), RF (pentane/EtOAc 99:1): 0.21; 1H NMR (300 MHz, CDCl3):
(64.2 mg, 0.30 mmol, quantitative). 98:2 e.r. ½a D24
ꢃ ¼ꢁ37.6 (c 0.88,
d
¼7.34 (m, 2H), 6.91e6.88 (m, 2H), 6.79e6.70 (m, 3H), 5.68 (dd,
CH2Cl2), RF (pentane/EtOAc 99:1): 0.36; 1H NMR (300 MHz,
J¼8.8, 8.8 Hz, 1H), 3.81 (s, 3H), 3.77 (s, 3H), 3.55 (dd, J¼15.8, 9.2 Hz,
1H), 3.24e3.15 (m, 1H); 13C NMR (75 MHz, CDCl3): 159.4, 154.2,
153.7, 133.9, 127.7, 127.3, 113.9, 112.9, 111.1, 109.2, 84.2, 56.0, 55.3,
38.7; GCeMS: Rt (50_40): 9.9 min; EI: 152 (8), 241 (9), 254 (11),
256 (100), 257 (18); ATR-FTIR (cmꢁ1); ATR-FTIR (cmꢁ1): 3304,
2966, 2840, 1610, 1586, 1505, 1470, 1436, 1307, 1246, 1206, 1180,
1142, 1112, 1018, 941, 916, 831, 789, 758, 737, 634; HPLC (AD-H,
elute: hexane/i-PrOH¼97/3, detector: 230 nm, flowrate: 1.0 mL/
min), t1(major)¼15.5 min, t2(minor)¼17.9 min.
CDCl3):
d
¼7.42e7.32 (m, 5H), 6.91e6.76 (m, 3H), 5.78 (dd, J¼9.3,
8.3 Hz, 1H), 3.62 (dd, J¼15.9, 9.4 Hz, 1H), 3.25e3.17 (m, 1H); 13C
NMR (75 MHz, CDCl3): 159.3, 156.2, 155.7, 141.7, 128.8, 128.3,
127.9, 125.8, 114.5, 114.2, 112.3, 111.9, 109.6, 109.4, 84.7, 38.7, 38.7;
Rt (50_40): 8.5 min; EI: 165 (24), 183 (23), 197 (14), 199 (15), 212
(16), 213 (44), 214 (100), 215 (16); ATR-FTIR (cmꢁ1): 3062, 2924,
2850, 1738, 1618, 1482, 1456, 1439, 1368, 1328, 1315, 1255, 1221,
1193, 1154, 1121, 1094, 1077, 1024, 968, 922, 910, 872, 811, 761, 743,
698, 662, 594, 539; HPLC (AD-H, elute: hexane/i-PrOH¼99/1,
detector: 210 nm, flowrate: 0.5 mL/min), t1(major)¼17.6 min,
t2(minor)¼18.9 min.
4.3.2.7. (S)-5-Methoxy-2-phenyl-2,3-dihydrobenzofuran (3g). Foll-
owing the general procedure, the hydrogenation reaction was carried
out for 16 h (in this case, hydrogenation was performed at 60 bar (H2)
and 40 ꢀC). The product was obtained as white solid (67.8 mg,
4.3.2.11. (S)-5-Fluoro-2-(4-fluorophenyl)-2,3-dihydrobenzofuran
(3k). Following the general procedure, the hydrogenation re-
action was carried out for 16 h. The product was obtained as
white solid (69.7 mg, 0.30 mmol, quantitative). 98:2 e.r.
0.30 mmol, quantitative). 99:1 e.r. ½a D24
ꢃ
¼ꢁ12.9 (c 1.00, CH2Cl2), RF
(pentane/EtOAc 99:1): 0.32; 1H NMR (300 MHz, CDCl3):
d
¼7.45e7.33
(m, 5H), 6.82 (m, 2H), 6.73 (dd, J¼8.7, 2.6 Hz, 1H), 5.76 (dd, J¼8.7,
8.7 Hz, 1H), 3.79 (s, 3H), 3.64 (dd, J¼15.7, 9.3 Hz, 1H), 3.22 (dd, J¼15.7,
8.2 Hz, 1H); 13C NMR (75 MHz, CDCl3): 154.4, 153.9, 142.1, 128.7, 128.1,
127.6, 125.9, 113.1, 111.3, 109.3, 84.3, 56.1, 38.9; GCeMS: Rt (50_40):
9.2 min; EI: 152 (10), 165 (39), 225 (14), 226 (100), 227 (17); ATR-FTIR
(cmꢁ1): 3038, 2995, 2958, 2917, 2834, 1603, 1485, 1469, 1434, 1363,
1306, 1251, 1230,1196,1184,1133,1113, 1080,1034,1002, 961, 936, 916,
874, 806, 764, 735, 702, 627, 566, 546, 482; HPLC (AD-H, elute: hex-
ane/i-PrOH¼99/1, detector: 230 nm, flowrate: 0.5 mL/min),
t1(minor)¼26.6 min, t2(major)¼28.7 min.
½
a 2D4
ꢃ
¼ꢁ95.4 (c 1.00, CH2Cl2), RF (pentane/EtOAc 99:1): 0.33; 1H
NMR (300 MHz, CDCl3):
d
¼7.40e7.35 (m, 2H), 7.07 (dd, J¼8.7,
8.7 Hz, 2H), 6.92e6.83 (m, 2H), 6.76 (dd, J¼8.6, 4.3 Hz, 1H), 5.75
(dd, J¼8.8, 8.8 Hz, 1H), 3.65e3.56 (m, 1H), 3.17 (ddd, J¼15.9, 8.3,
1.1 Hz, 1H); 13C NMR (75 MHz, CDCl3): 164.3, 161.0, 159.3, 156.2,
155.5, 155.5, 137.5, 137.4, 127.8, 127.7, 127.7, 127.6, 115.9, 115.6,
114.6, 114.3, 112.3, 111.9, 109.6, 109.5, 84.1, 38.8, 38.7, 38.7;
GCeMS: Rt (50_40): 8.5 min; EI: 107 (17), 183 (30), 201 (19), 230
(12), 231 (33), 232 (100), 233 (15); ATR-FTIR (cmꢁ1): 2905, 1681,
1605, 1512, 1477, 1439, 1222, 1191, 1118, 1095, 1014, 974, 921, 864,
834, 819, 778, 740, 712, 615, 541; HPLC (OD-H, elute: hexane/i-
PrOH¼97/3, detector: 230 nm, flowrate: 1.0 mL/min),
t1(major)¼6.8 min, t2(minor)¼7.5 min.
4.3.2.8. (S)-2-(4-Fluorophenyl)-5-methoxy-2,3-dihydrobenzofuran
(3h). Following the general procedure, the hydrogenation reaction
was carried out for 16 h. The product was obtained as white solid
(73.2 mg, 0.30 mmol, quantitative). 99:1 e.r. ½a D24
ꢃ
¼ꢁ15.9 (c 1.00,
4.3.2.12. 1-Methyl-2,3-dihydroindene (8). Following the general
procedure, the hydrogenation reaction was carried out for 16 h. The
product was obtained as colourless oil (39.6 mg, 0.30 mmol,
CH2Cl2), RF (pentane/EtOAc 99:1): 0.29; 1H NMR (300 MHz, CDCl3):
d¼7.18(m,2H), 7.01(m, 2H),6.75e6.68(m, 4H),5.54(dd, J¼8.9,8.9Hz,
1H), 3.63 (s, 3H), 3.41 (dd, J¼15.7, 9.3 Hz, 1H), 3.05 (dd, J¼15.7, 8.4 Hz,
1H); 13C NMR (75 MHz, CDCl3): 163.8, 161.3, 154.5, 153.7, 137.9, 127.7,
127.7,127.6,127.6,127.4,115.7,115.5,113.2,111.3,109.3, 83.7, 56.1, 39.0;
GCeMS: Rt (50_40):9.1 min; EI:109(10),183(37), 244 (100), 245(16);
ATR-FTIR (cmꢁ1): 3000, 2956, 2848,1603,1511,1481,1224,1202,1132,
1032, 973, 929, 879, 836, 807, 767, 737, 625, 566, 542, 523; HPLC (AD-
H, elute: hexane/i-PrOH¼99/1, detector: 210 nm, flowrate: 0.5 mL/
min), t1(major)¼36.2 min, t2(minor)¼38.9 min.
quantitative). 58:42 e.r. ½a D24
ꢃ ¼ꢁ2.1 (c 0.62, CH2Cl2), RF (pentane):
0.64; 1H NMR (300 MHz, CDCl3): 7.23e7.13 (m, 4H), 3.25e3.13 (m,
1H), 2.91e2.83 (m, 2H), 2.33e2.28 (m, 1H), 1.61e1.53 (m, 1H), 1.29
(d, J¼6.9 Hz, 3H); 13C NMR (75 MHz, CDCl3): 126.2, 124.5, 123.3,
39.5, 34.9, 31.6, 20.0; GCeMS: Rt (50_40): 7.5 min; EI: 91 (13), 115
(33), 116 (10), 117 (100), 118 (11), 131 (9), 132 (29); ATR-FTIR (cmꢁ1):
3039, 2954, 2862, 1717, 1607, 1478, 1456, 1226, 752; HPLC (OJ-H,
elute: hexane/i-PrOH¼95/5, detector: 230 nm, flowrate: 0.5 mL/
min), t1(minor)¼7.6 min, t2(major)¼7.8 min.
4.3.2.9. (S)-5-Fluoro-2-(4-methoxyphenyl)-2,3-dihydrobenzofuran
(3i). Following the general procedure, the hydrogenation reaction
was carried out for 16 h (in this case, hydrogenation was performed
at 60 bar (H2) and 40 ꢀC). The product was obtained as white solid
4.3.2.13. 3-Methyl-2,3-dihydrobenzofuran (9). Following the
general procedure, the hydrogenation reaction was carried out for
16 h. The product was obtained as colourless oil (40.2 mg mg,
(73.2 mg, 0.30 mmol, quantitative). 96:4 e.r. ½a D24
ꢃ
¼þ1.5 (c 0.65,
0.30 mmol, quantitative). 97:3 e.r. ½a D24
ꢃ
¼þ10.2 (c 0.50, CH2Cl2), RF
CH2Cl2), RF (pentane/EtOAc 99:1): 0.25; 1H NMR (300 MHz, CDCl3):
(pentane): 0.76; 1H NMR (300 MHz, CDCl3):
d
¼7.16 (m, 2H), 6.84
d¼7.33 (m, 2H), 6.91 (m, 3H), 6.85 (m, 1H), 6.74 (dd, J¼8.7, 4.2 Hz,
(ddd, J¼7.4, 7.4, 0.9 Hz, 1H), 6.78 (d, J¼8.0 Hz, 1H), 4.94 (ddd, J¼8.8,