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W. Lin et al. / Tetrahedron 63 (2007) 2787–2797
(m), 1584 (w), 1404 (w), 1369 (w), 1278 (s), 1222 (w), 1108
(m), 1078 (w), 1016 (m), 862 (m), 843 (m), 816 (w), 761 (m),
718 (w), 704 (m), 650 (w). HRMS (EI) for C19H17O3N
(307.1208): found 307.1222.
4.6.4. 3-Chloro-5-iodo-11-oxa-4-aza-tricyclo[6.2.1.02,7]-
undeca-2(7),3,5,9-tetraene (4d). Prepared according to
TP 2 from 4-chloro-benzenesulfonic acid 2-chloro-4,6-
diiodo-pyridin-3-yl ester (3d) (556 mg, 1.0 mmol), i-
PrMgCl (1.21 mL, 1.05 mmol, 0.87 M in THF) and furan
(340 mg, 5.0 mmol). Reaction condition: ꢁ78 ꢀC, 0.5 h;
25 ꢀC, 16 h. Purification by flash chromatography (n-
pentane/diethyl ether¼30:1) yielded 4d as a white solid
4.6.1. 11-Oxa-4-aza-tricyclo[6.2.1.02,7]undeca-2(7),3,5,9-
tetraene (4a). Prepared according to TP 2 from 4-iodo-
pyridin-3-yl 4-chlorobenzenesulfonate (3a) (396 mg,
1.0 mmol), i-PrMgCl (1.21 mL, 1.05 mmol, 0.87 M in
THF) and furan (340 mg, 5.0 mmol). Reaction condition:
ꢁ78 ꢀC, 0.5 h; 25 ꢀC, 2.5 h. Purification by flash chromato-
graphy (n-pentane/diethyl ether¼2:1) yielded 4a as a yellow
1
(98 mg, 32%). Mp: 123.1–124.2 ꢀC. H NMR (300 MHz,
3
CDCl3, 25 ꢀC) d/ppm: 7.59 (s, 1H), 7.12 (dd, J¼5.5 Hz,
3J¼1.9 Hz, 1H), 6.99 (dd, 3J¼5.5 Hz, 3J¼1.9 Hz, 1H),
5.80–5.77 (m, 1H), 5.73–5.70 (m, 1H). 13C NMR (75 MHz,
CDCl3, 25 ꢀC) d/ppm: 164.2, 143.9, 142.9, 141.9, 140.7,
126.6, 113.0, 81.9, 80.5. MS (70 eV, EI) m/z (%): 307 (6),
305 (20) [M+], 281 (7), 279 (23), 277 (12), 241 (9), 152
(44), 151 (13), 150 (100), 149 (12), 123 (12), 115 (7), 114
(25). IR (KBr) ~n (cmꢁ1): 1598, 1553, 1402, 1300, 1284,
1204, 1134, 1054, 853, 814, 805, 728, 642. HRMS (EI) for
C9H5ON35ClI (304.9104): found 304.9087.
1
oil (79 mg, 54%). H NMR (300 MHz, CDCl3, 25 ꢀC)
d/ppm: 8.40 (s, 1H), 8.23 (d, 3J¼4.6 Hz, 1H), 7.18 (d,
3J¼4.6 Hz, 1H), 6.99 (dd, 3J¼5.6 Hz, 3J¼1.8 Hz, 1H),
3
3
6.93 (dd, J¼5.6 Hz, J¼1.8 Hz, 1H), 5.77–5.75 (m, 1H),
13
5.68–5.66 (m, 1H). C NMR (75 MHz, CDCl3, 25 ꢀC)
d/ppm: 158.8, 147.2, 144.1, 143.3, 141.8, 139.6, 116.0,
81.5, 80.4. MS (70 eV, EI) m/z (%): 145 (8) [M+], 119
(21), 118 (9), 117 (100), 116 (20), 91 (8), 90 (39), 89 (40),
64 (7), 63 (18). IR (film) ~n (cmꢁ1): 1584 (w), 1414 (w),
1282 (w), 1126 (w), 1019 (w), 995 (w), 876 (w), 850 (s),
836 (m), 705 (m), 645 (w), 592 (w). HRMS (EI) for
C9H7ON (145.0528): found 145.0525.
4.6.5. 5-Bromo-3-methoxy-11-oxa-4-aza-tricyclo-
[6.2.1.02,7]undeca-2(7),3,5,9-tetraene
(4e).
Prepared
according to TP 2 from 4-chloro-benzenesulfonic acid 4,6-
dibromo-2-methoxy-pyridin-3-yl ester (3e) (229 mg,
0.5 mmol), i-PrMgCl$LiCl (0.51 mL, 0.51 mmol, 1.00 M
in THF) and furan (170 mg, 2.5 mmol). Reaction condition:
ꢁ78 ꢀC, 0.5 h; 25 ꢀC, 4 h. Purification by flash chromato-
graphy (n-pentane/diethyl ether¼100:1) yielded 4e as a col-
4.6.2. 3-Iodo-11-oxa-4-aza-tricyclo[6.2.1.02,7]undeca-
2(7),3,5,9-tetraene (4b). Prepared according to TP 2 from
2,4-diiodo-pyridin-3-yl 4-chlorobenzenesulfonate (3b)
(522 mg, 1.0 mmol), i-PrMgCl (1.21 mL, 1.05 mmol,
0.87 M in THF) and furan (340 mg, 5.0 mmol). Reaction
condition: ꢁ78 ꢀC, 0.5 h; 25 ꢀC, 1.5 h. Purification by flash
chromatography (n-pentane/diethyl ether¼10:1) yielded 4b
as a white solid (123 mg, 45%). Mp: 91.8–93.8 ꢀC. 1H NMR
(300 MHz, CDCl3, 25 ꢀC) d/ppm: 8.03 (d, 3J¼4.7 Hz, 1H),
1
ourless oil (100 mg, 78%). H NMR (300 MHz, CDCl3,
25 ꢀC) d/ppm: 7.12–7.08 (m, 2H), 6.97 (dd, 3J¼5.5 Hz,
3J¼1.9 Hz, 1H), 5.84–5.81 (m, 1H), 5.67–5.64 (m, 1H),
13
3.93 (s, 3H). C NMR (75 MHz, CDCl3, 25 ꢀC) d/ppm:
166.2, 155.9, 143.6, 141.7, 135.7, 129.3, 115.0, 81.9, 79.3,
54.1. MS (70 eV, EI) m/z (%): 255 (15), 253 (17) [M+],
229 (29), 227 (52), 226 (99), 225 (34), 224 (100), 212
(15), 210 (17), 198 (29), 197 (18), 196 (23), 195 (13), 185
(29), 183 (27), 148 (26), 146 (20), 145 (19), 131 (21), 130
(41), 116 (19), 115 (17), 103 (15), 102 (13), 76 (19). IR
(neat) ~n (cmꢁ1): 2950 (w), 1600 (m), 1572 (s), 1458 (m),
1411 (w), 1354 (vs), 1279 (m), 1079 (m), 1060 (m), 994
(m), 864 (m), 842 (m), 728 (w), 649 (w). HRMS (EI) for
C10H8O2N79Br (252.9738): found 252.9716.
3
3
3
7.16 (d, J¼4.7 Hz, 1H), 7.14 (dd, J¼5.6 Hz, J¼1.8 Hz,
3
3
1H), 7.03 (dd, J¼5.6 Hz, J¼1.8 Hz, 1H), 5.85–5.82 (m,
1H), 5.61–5.58 (m, 1H). 13C NMR (75 MHz, CDCl3,
25 ꢀC) d/ppm: 160.4, 152.0, 148.8, 143.0, 142.5, 115.7,
107.1, 84.0, 83.0. MS (70 eV, EI) m/z (%): 271 (22) [M+],
245 (11), 243 (29), 144 (14), 118 (20), 117 (10), 116
(100), 115 (35), 89 (28), 63 (11). IR (KBr) ~n (cmꢁ1): 1560,
1410, 1396, 1270, 1116, 856, 832, 731, 654. HRMS (EI)
for C9H6ONI (270.9494): found 270.9507.
4.6.6. 3-(4-Chloro-phenylsulfanyl)-5-methyl-11-oxa-4-
aza-tricyclo[6.2.1.02,7]undeca-2(7),3,5,9-tetraene (4f).
Prepared according to TP 2 from 4-chloro-benzenesulfonic
acid 4-bromo-2-(4-chloro-phenylsulfanyl)-6-methylpyri-
din-3-yl ester (3f) (253 mg, 0.5 mmol), i-PrMgCl$LiCl
(0.51 mL, 0.51 mmol, 1.00 M in THF) and furan (170 mg,
2.5 mmol). Reaction condition: ꢁ78 ꢀC, 0.5 h; 25 ꢀC, 1 h.
Purification by flash chromatography (n-pentane/diethyl
ether¼3:1) yielded 4f as a yellow solid (134 mg, 88%).
4.6.3. 3-Iodo-5-methyl-11-oxa-4-aza-tricyclo[6.2.1.02,7]-
undeca-2(7),3,5,9-tetraene (4c). Prepared according to TP
2 from 2,4-diiodo-6-methylpyridin-3-yl 4-chlorobenzene-
sulfonate (3c) (536 mg, 1.0 mmol), i-PrMgCl (1.21 mL,
1.05 mmol, 0.87 M in THF) and furan (340 mg,
5.0 mmol). Reaction condition: ꢁ78 ꢀC, 0.5 h; 25 ꢀC, 6 h.
Purification by flash chromatography (n-pentane/diethyl
1
ether¼2:1) yielded 4c as a yellow oil (214 mg, 75%). H
NMR (300 MHz, CDCl3, 25 ꢀC) d/ppm: 7.09 (dd, 3J¼
Mp: 98.1–101.2 ꢀC. H NMR (300 MHz, CDCl3, 25 ꢀC)
1
3
3
5.6 Hz, J¼1.9 Hz, 1H), 7.00 (s, 1H), 6.96 (dd, J¼5.6 Hz,
3J¼1.9 Hz, 1H), 5.77–5.75 (m, 1H), 5.54–5.52 (m, 1H),
d/ppm: 7.29–7.20 (m, 4H), 6.92 (s, 1H), 6.82 (dd, 3J¼
3
3
3
5.5 Hz, J¼1.9 Hz, 1H), 6.57 (dd, J¼5.5 Hz, J¼1.9 Hz,
1H), 5.57–5.54 (m, 1H), 5.34–5.31 (m, 1H), 2.41 (s, 3H).
13C NMR (75 MHz, CDCl3, 25 ꢀC) d/ppm: 160.7, 157.2,
146.4, 143.0, 142.7, 141.7, 133.8, 133.1, 132.4, 129.4,
114.9, 81.7, 80.5, 24.5. MS (70 eV, EI) m/z (%): 303 (35),
302 (23), 301 (88) [M+], 300 (20), 275 (43), 274 (63), 273
(70), 272 (100), 257 (24), 247 (29), 240 (34), 237 (31),
236 (23), 108 (29), 103 (31), 77 (42), 63 (20). IR (neat)
~n (cmꢁ1): 3077 (w), 2612 (w), 1558 (m), 1476 (s), 1443
13
2.44 (s, 3H). C NMR (75 MHz, CDCl3, 25 ꢀC) d/ppm:
160.6, 158.6, 148.7, 143.0, 142.0, 115.8, 105.8, 83.8, 82.9,
24.2. MS (70 eV, EI) m/z (%): 285 (12) [M+], 257 (20),
132 (14), 130 (100), 129 (28), 103 (35), 77 (13). IR (neat)
~n (cmꢁ1): 1613 (w), 1549 (s), 1428 (m), 1322 (m), 1280
(m), 1180 (s), 1080 (s), 1004 (w), 910 (w), 865 (w), 851
(vs), 838 (s), 795 (m), 727 (m), 702 (s), 646 (m). HRMS
(EI) for C10H8ONI (284.9651): found 284.9633.