The Journal of Organic Chemistry
Page 12 of 14
(m, 6H); (Z) 7.66 (d, J = 8.5 Hz, 2H), 7.41 (d, J = 7.5 Hz, 1H),
1460, 1348, 1095, 971; HRMS (DART) m/z: [M + H]+ Calcd for
C23H29Co2O8 551.0521; Found 551.0501.
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2
3
4
5
6
7
8
7.30-7.19 (m, 5H), 5.47-5.42 (m, 1H), 5.33 (td, J = 10.8, 6.8 Hz,
1H), 4.70 (s, 2H), 4.92 (s, 2H), 4.45 (s, 2H), 3.711 (s, 6H), 3.454
(t, J = 6.5 Hz, 2H), 3.450 (s, 2H), 2.55 (d, J = 8.0 Hz, 2H), 2.42 (s,
3H), 1.98-1.92 (m, 2H), 1.56-1.51 (m, 2H), 1.40-1.25 (m, 6H);
13C NMR (125 MHz, CDCl3, ppm) δ (E) 170.6, 143.6, 137.5,
136.4, 135.5 132.8, 129.6, 128.6, 128.0, 127.8, 127.63, 127.61,
123.5, 122.0, 119.6, 70.2, 69.8, 57.4, 53.9, 52.8, 49.5, 41.5,
35.3, 31.4, 28.8, 27.5, 27.0, 25.1, 21.6; (Z) 170.8, 143.4, 137.4,
136.3, 134.7, 133.2, 129.4, 128.4, 127.5, 127.4, 122.7, 123.9,
119.1, 71.1, 70.4, 57.0, 54.2, 52.7, 49.6, 44.1, 30.2, 29.3, 28.1,
27.7, 26.3, 24.9 (3 C’s, absent); IR (neat, ATR, cm-1): 3027,
2926, 2855, 1735, 1437, 1156, 1089; HRMS (ESI) m/z: [M +
Na]+ Calcd for C33H41Br2NNaO7S 776.0868, found 776.0882.
Complex 50. A flame dried flask with dicobalt octacarbonyl
(236 mg, 0.690 mmol) and 64 (316 mg, 0.530 mmol), was
flushed with nitrogen, then DCM (22 mL) was added. The mix-
ture was stirred at rt 16 h. Solvent was removed in vacuo.
Chromatography with 3:1 hexanes/EtOAc gave 327 mg (80%
yield, E:Z ratio 3:1) of a red viscous oil. 1H NMR (500 MHz,
CDCl3, ppm) δ (E) 7.45 (d, J = 8.5 Hz, 2H), 7.19-7.04 (m, 4H),
7.12 (d, J = 8.0 Hz, 2H), 5.48 (dt, J = 14.5, 7.1 Hz, 1H), 5.24 (dt, J
= 15.3, 7.6 Hz, 1H), 4.74 (s, 2H), 4.64 (s, 2H), 4.39 (s, 2H), 3.73
(s, 6H), 4.47 (t, J = 6.5 Hz, 2H), 3.40 (s, 2H), 2.82 (d, J = 7.5 Hz
2H), 2.36 (s, 3H), 2.01 (td, J = 5.8, 5.8 Hz, 2H), 1.56 (p, J = 6.6
Hz, 2H), 1.43-1.29 (m, 6H); (Z) 7.27-7.26 (m, 2H), 7.19-7.04
(m, 6H), 5.51-5.45 (m, 1H), 5.33 (dt, J = 11.0, 6.8 Hz, 1H), 4.73
(s, 2H), 4.60 (s, 2H), 4.22 (s, 2H), 3.75 (s, 6H), 3.68 (s, 2H), 3.33
(t, J = 6.0 Hz, 2H), 2.70 (d, J = 7.0 Hz, 2H), 2.33 (s, 3H), 2.04
(td, J = 7.0 Hz, 2H), 1.58-1.29 (m, 8H); 13C NMR (125 MHz,
CDCl3, ppm) δ (E) 199.2, 170.7, 143.0, 137.1, 136.8, 135.7,
133.9, 129.6, 129.4, 129.3, 127.8, 127.6, 127.2, 123.5, 90.5,
90.3, 71.0, 70.2, 58.7, 53.0, 52.5, 50.5, 35.7, 34.7, 31.1, 29.0,
27.0, 26.5, 24.7, 21.4; (Z) 199.2, 170.7, 142.7, 137.3, 136.7,
134.0, 131.6, 129.7, 129.1, 128.0, 126.9, 122.8, 94.7, 90.4, 71.4,
70.4, 58.2, 54.2, 52.7, 51.7, 39.0, 32.0, 30.9, 27.7, 27.1, 25.7,
24.8 (3 C’s, absent); IR (neat, ATR, cm-1): 3031, 2934, 2093,
2051, 2018, 1735, 1437, 1207, 1160, 1092; HRMS (ESI) m/z:
[M + Na]+ Calcd for C39H41Co2NNaO13S 904.0855; Found
904.0874.
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15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
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42
43
44
45
46
47
48
49
50
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54
55
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58
59
60
Dimethyl
14,15-dehydro-17-tosyl-
4,5,6,7,8,11,13,16,17,18-decahydro-1H-
benzo[c][1]oxa[6]azacycloicosine-12,12(3H)-
dicarboxylate (64). A flame dried flask equipped with a re-
flux condenser was charged with zinc dust (339 mg, 5.19
mmol). The zinc dust was stirred with 1M HCl, rinsed with
water, and flame dried in a flask prior to use. A solution of 63
(654 mg, 0.866 mmol) in THF (43 mL) was added. The mix-
ture was heated at reflux and stirred 16 h. The mixture was
diluted with EtOAc and filtered over Celite. Solvent was re-
moved in vacuo. Chromatography with 3:1 hexanes/EtOAc
gave 452 mg (88% yield, E:Z ratio 3:1) of a white solid. 1H
NMR (500 MHz, CDCl3, ppm) δ (E) 7.81 (d, J = 8.5 Hz, 2H), 7.59
(d, J = 8.0 Hz, 1H), 7.37 (d, J = 8.5 Hz, 2H), 7.34-7.24 (m, 3H),
5.07 (dt, J = 14.7, 7.1 Hz), 4.92 (dt, J = 14.8, 7.4 Hz, 1H), 4.49 (s,
2H), 4.48 (s, 2H), 3.98 (s, 2H), 3.72 (s, 6H), 3.45 (t, J = 6.0 Hz,
2H), 2.63 (s, 2H), 2.52 (d, J = 7.5 Hz, 2H), 2.42 (s, 3H), 1.96 (td,
J = 6.0, 6.0 Hz, 2H), 1.58 (p, J = 6.3 Hz, 2H), 1.39-1.27 (m, 4H),
1.22-1.16 (m, 2H); (Z) 7.75 (d, J = 8.0 Hz, 2H), 7.54 (d, J = 7.5
Hz, 1H), 7.34-7.24 (m, 5H), 5.46 (dt, J = 11.0, 7.5 Hz, 1H), 4.95-
4.89 (m, 1H), 4.55 (s, 2H), 4.48 (s, 2H), 4.07 (s, 2H), 3.72 (s,
6H), 3.40 (t, J = 5.7 Hz, 2H), 2.60 (d, J = 8.0 Hz, 2H), 2.59 (s,
2H), 2.43 (s, 3H), 1.88 (td, J = 7.2Hz, 2H), 1.52 (p, J = 6.4 Hz,
2H), 1.39-1.27 (m, 4H), 1.22-1.16 (m, 2H); 13C NMR (125 MHz,
CDCl3, ppm) δ (E) 170.23, 143.45, 137.1, 136.50, 135.2, 129.8,
129.6, 129.1, 128.8 127.6, 127.50, 122.7, 80.7, 76.7, 71.67,
69.4, 56.4, 52.82, 45.0, 36.2, 35.3, 31.9, 28.4, 27.9, 26.6, 24.9,
22.5, 21.5 (one C, absent); (Z) 170.19, 143.36, 136.48, 135.3,
134.8, 130.2, 129.5, 129.3, 128.6, 127.8, 127.52, 122.2, 80.8,
76.6, 71.73, 69.2, 56.8, 52.79, 46.5, 37.4, 30.2, 29.0, 28.6, 27.6,
26.5, 25.1, 23.1, 21.6 (one C, absent); IR (neat, ATR, cm-1):
3027, 2926, 2858, 2359, 1735, 1437, 1347, 1210, 1160, 1089,
1066; HRMS (DART) m/z: [M + H]+ Calcd for C33H42NO7S
596.2677; Found 596.2675.
Cyclopentenone 65. A flame-dried flask was charged with
complex 49 (115 mg, 0.21 mmol) and acetonitrile (20 mL).
The solution was heated to 50 °C and NMO (147 mg, 1.25
mmol in 10 mL MeCN) was added dropwise over 14 h. Upon
completion, the reaction was cooled to rt, solvent was re-
moved in vacuo and chromatography with 1:1 hexanes/Et2O
1
gave 27 mg (44% yield) of a colorless oil. H NMR (400 MHz,
CDCl3, ppm) δ (Major) 4.70 (d, J = 16.4 Hz, 1H), 4.53 (d, J =
16.0 Hz, 1H), 4.34 (dd, J = 14.0, 14.0 Hz, 1H), 4.24 (d, J = 12.8
Hz, 1H), 4.04 (d, J = 12.8 Hz, 1H), 3.50-3.44 (m, 1H), 3.42-3.36
(m, 1H), 3.24-3.18 (m, 2H), 2.26 (bt, J = 2.6 Hz, 1H), 2.19-2.11
(m, 1H), 1.76-1.64 (m, 1H), 1.65-1.50 (m, 2H), 1.47-1.14 (m,
14H), (Minor) 4.66 (d, J = 16.8 Hz, 1H), 4.60 (d, J = 16.4 Hz,
1H), 4.19 (dt, J = 11.6, 0.8 Hz, 1H), 4.15 (dd, J = 8.4, 8.4 Hz, 1H),
3.96 (d, J = 11.6 Hz, 1H), 3.56 (dd, J = 11.2, 8.4 Hz, 1H), 3.50-
3.44 (m, 1H), 3.36-3.18 (m, 2H), 2.72-2.67 (m, 1H), 1.76-1.64
(m, 2H), 1.47-1.14 (m, 16H); 13C NMR (100 MHz, CDCl3, ppm)
δ (Major) 209.7, 180.2, 133.9, 71.4, 69.5, 64.9, 61.4, 49.2, 47.5,
28.1, 27.7, 27.3, 26.7, 26.6, 26.4, 26.0, 25.61, 24.5; (Minor)
210.4, 177.4, 130.9, 70.7, 67.3, 65.3, 61.8, 49.7, 47.7, 28.7,
27.8, 27.6, 26.9, 25.59, 25.2, 24.2, 23.7 (1 C signal overlaps
around 27.0 ppm); IR (neat ATR): 2925, 2855, 1712, 1676,
1094, 1025, 986, 889, 733; HRMS (DART) m/z: [M + H]+ Calcd
for C18H29O3 293.2111; Found 293.2101.
Cyclopentenone 66. Prior to reaction, glassware was
soaked in concentrated nitric acid for 24 h, then
KOH/iPrOH/H2O for 24 h.53 Acetonitrile was submitted to 3
freeze/pump/thaw cycles prior to use. A flame dried flask
with complex 50 (100 mg, 0.113 mmol) was flushed with ni-
trogen, then acetonitrile (11 mL) was added. An acetonitrile
(5.0 mL) solution of NMO (80 mg, 0.681 mmol) was added
dropwise with stirring at 50 °C over 14 h. The mixture was
stirred at 50 °C for another 4 h. Solvent was removed in vacuo.
Chromatography with 3:1 hexanes/EtOAc gave 28 mg (40%
yield, 5.5:1 diastereomeric ratio, trans major) of a clear color-
less oil. Further chromatography was repeated with prepara-
Complex 49. To a solution of 1,6-dioxacyclononadec-8-en-
3-yne (132 mg, 0.50 mmol)36 in DCM (10 mL) Co2(CO)8 (171
mg, 0.50 mmol) was added. The mixture was stirred at rt for 9
h. The solvent was removed in vacuo. Chromatography with
19:1 petroleum ether/Et2O gave 242 mg (88% yield, E:Z ratio
1
2.5:1) of a red oil. H NMR (400 MHz, CDCl3, ppm) δ (E) 5.71-
5.51 (m, 2H), 4.64 (s, 2H), 4.61 (s, 2H), 4.14 (d, J = 5.6 Hz, 2H),
3.58 (t, J = 5.8 Hz, 2H), 2.08 (bd, J = 6.0 Hz, 2H), 1.59-1.55 (m,
2H), 1.40-1.28 (m, 14H), (Z) 5.71-5.51 (m, 2H), 4.67 (s, 2H),
4.64 (s, 2H), 4.23 (d, J = 6.0 Hz, 2H), 3.58 (t, J = 5.8 Hz, 2H),
2.08 (bd, J = 6.0 Hz, 2H), 1.59-1.55 (m, 2H), 1.40-1.28 (m,
14H); 13C NMR (100 MHz, CDCl3, ppm) δ (E) 199.5, 193.2,
135.1, 126.8, 94.23, 94.22, 71.33, 71.29, 71.0, 68.8, 31.6, 28.9,
27.9, 27.48, 27.39, 27.13, 27.09, 27.04, 24.7; (Z) 199.5, 193.2,
133.9, 126.3, 94.26, 94.19, 71.6, 70.9, 69.8, 66.4, 29.0, 28.3,
27.66, 27.59, 27.57, 27.26, 27.1 (2 C signals overlap), 26.9,
25.0; IR (neat ATR): 2928, 2857, 2092, 2049, 2013, 1622,
12
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