Prostanes B1 by Intermolecular Pauson–Khand Reaction
CH), 6.80 (d, J = 15.8 Hz, 1 H, CH) ppm. 13C NMR (100 MHz, 29.7 (CH2), 34.2 (CH2), 35.8 (CH2), 39.2 (CH2), 51.6 (CH3), 70.0
CDCl3): δ = 13.7 (CH3), 16.5 (CH2), 25.0 (CH2), 25.4 (CH2), 25.8 (CH), 74.4 (C), 121.1 (CH), 121.5 (CH), 124.2 (CH), 126.1 (CH),
(CH2), 29.2 (CH2), 29.3 (CH2), 29.4 (CH2), 34.0 (CH2), 34.2 (CH2), 135.5 (C), 153.4 (C), 167.5 (C), 174.4 (C) ppm. MS (ESI+; H2O/
37.4 (CH2), 51.7 (CH3), 72.6 (CH), 124.0 (CH), 140.1 (CH), 143.0 CH3CN): m/z (%) = 424 (100) [M + H]+. HRMS (ESI+; H2O/
(C), 162.7 (C), 174.4 (C), 209.6 (C) ppm.
CH3CN, 1:1): calcd. for C22H34NO3S2 [M + H]+ 424.19746; found
424.19751.
(S)-2-[(2-tert-Butoxybutyl)thio]benzo[d]thiazole (17a): A catalytic
amount of Mg(ClO4)2 (158 mg, 10 mol-%) and β-hydroxythioether
(S)-2-[(2-tert-Butoxy)butyl]sulfonylbenzo[d]thiazole (18a): A solu-
9a (1.7 g, 7.1 mmol) were dissolved in CH2Cl2 (20 mL) in a flame- tion of ammonium molybdate tetrahydrate (1.10 g, 15 mol-%) in
dried two-necked flask equipped with a condenser. Then, Boc2O
(1.5 g, 7.1 mmol) was added, and bubbling was observed. The mix-
ture was stirred at reflux, and once the bubbling had stopped, an
excess of Boc2O (13.5 g, 36.9 mmol) was added in portions until
the starting material had been consumed. The mixture was diluted
with water and extracted with CH2Cl2. The organic phase was sep-
arated, dried with MgSO4, and filtered, and the solvent was re-
moved. The crude product was purified by flash chromatography,
using hexanes/ethyl acetate mixtures with increasing polarity, to
yield tert-butyl ether 17a (1.9 g, 90%) as a slightly yellow oil. [α]D
H2O2 (30% aq.; 7.5 mL) was added by cannula under nitrogen to
a solution of sulfide 17a (1.77 g, 6.0 mmol) in ethanol (200 mL) at
0 °C. The resulting mixture was stirred at room temperature for 6 h
and was then quenched by the addition of water. The ethanol was
evaporated, and ethyl acetate was added. The aqueous phase was
extracted with ethyl acetate, and the combined organic extracts
were washed with water and brine and dried with anhydrous
MgSO4. Evaporation of the solvent gave a crude residue, which was
purified by flash chromatography, eluting with hexanes/ethyl ether
mixtures, to yield sulfone 18a (1.87 g, 95%) as a slightly yellow oil.
= –21 (c = 0.94, CHCl ). IR (film): ν = 2962, 2930, 1463, 1188, [α]D = –35 (c = 1.58, CHCl ). IR (film): ν = 2974, 1466, 1329,
˜
˜
3
3
996 cm–1. H NMR (400 MHz, CDCl3): δ = 0.96 (t, J = 8.0 Hz, 3
1149 cm–1. H NMR (400 MHz, CDCl3): δ = 0.95 (t, J = 7.6 Hz,
1
1
H, CH3), 1.26 (s, 9 H, CH3), 1.54–1.65 (m, 1 H, CH2), 1.67–1.78
3 H, CH3), 1.14 (s, 9 H, CH3), 1.58–1.68 (m, 1 H, CH2), 1.78–1.90
(m, 1 H, CH2), 3.37 (dd, J = 13.2, 6.8 Hz, 1 H, CH2), 3.57 (dd, J (m, 1 H, CH2), 3.66 (dd, J = 14.4, 7.6 Hz, 1 H, CH2), 3.74 (dd, J
= 13.2, 4.8 Hz, 1 H, CH2), 3.80 (q, J = 6.0 Hz, 1 H, CH), 7.31 = 14.4, 4.0 Hz, 1 H, CH2), 4.17–4.24 (m, 1 H, CH), 7.59 (td, J =
(ddd, J = 8.4, 7.2, 1.2 Hz, 1 H, CH), 7.43 (ddd, J = 8.4, 7.2, 1.3 Hz,
1 H, CH), 7.75 (ddd, J = 9.0, 1.2, 0.6 Hz, 1 H, CH), 7.84 (ddd, J
= 8.4, 1.2, 0.6 Hz, 1 H, CH) ppm. 13C NMR (100 MHz, CDCl3):
8.0, 1.6 Hz, 1 H, CH), 7.64 (td, J = 7.2, 1.4 Hz, 1 H, CH), 8.02
(dd, J = 8.0, 1.8 Hz, 1 H, CH), 8.22 (dd, J = 8.0, 1.2 Hz, 1 H, CH)
ppm. 13C NMR (100 MHz, CDCl3): δ = 9.5 (CH3), 28.5 (CH3),
δ = 9.2 (CH3), 28.0 (CH2), 28.5 (3 C, CH3), 38.9 (CH2), 71.1 (CH), 29.8 (CH2), 60.4 (CH2), 67.1 (CH), 75.2 (C), 122.5 (CH), 125.6
74.4 (C), 121.1 (CH), 121.5 (CH), 124.3 (CH), 126.1 (CH), 135.5
(C), 153.4 (C), 167.6 (C) ppm. MS (ESI+; H2O/CH3CN): m/z (%)
= 296 (3) [M + H]+. HRMS (ESI+; H2O/CH3CN, 1:1): calcd. for
C15H22NOS2 [M + H]+ 296.1143; found 296.1140.
(CH), 127.8 (CH), 128.2 (CH), 136.9 (C), 152.9 (C), 167.1 (C) ppm.
MS (ESI+; H2O/CH3CN): m/z (%) = 350 (95) [M + Na]+, 677 (100)
[2M + Na]+. HRMS (ESI+; H2O/CH3CN, 1:1): calcd. for
C
15H22NO3S2 [M + H]+ 328.1041; found 328.1045; calcd. for
C15H21NO3S2Na [M + Na]+ 350.0861; found 350.0869.
(S)-2-[(2-tert-Butoxyheptyl)thio]benzo[d]thiazole (17b): According
to the procedure described for 17a, 9b (850 mg, 3.02 mmol), Boc2O
(S)-2-[(2-tert-Butoxy)heptyl]sulfonylbenzo[d]thiazole (18b): Accord-
(5.93 g, 27.2 mmol), and Mg(ClO)4 (68 mg, 10 mol-%) were heated ing to the procedure described for 18a, 17b (855 mg, 2.53 mmol),
in refluxing anhydrous dichloromethane (15 mL) and gave 17b
(887 mg, 87%) as a slightly yellow oil. [α]D = –29 (c = 0.60, CHCl3).
Mo7O4(NH3)6·4H2O (470 mg, 15 mol-%), and H2O2 (30% aq.;
3.1 mL, 30.4 mmol) reacted in EtOH (84 mL) to give sulfone 18b
IR (film): ν = 2949, 2922, 1459 cm–1. 1H NMR (400 MHz, CDCl ): (815.1 mg, 87 %) as a slightly yellow oil. [α]D = –22 (c = 0.68,
˜
3
δ = 0.88 (t, J = 7.2 Hz, 3 H, CH3), 1.25 (s, 9 H, CH3), 1.27–1.61 CHCl ). IR (film): ν = 2907, 1475, 1334 cm–1. 1H NMR (400 MHz,
˜
3
(m, 6 H, CH2), 1.63–1.72 (m, 2 H, CH2), 3.38 (dd, J = 13.6, 7.2 Hz, CDCl3): δ = 0.86 (t, J = 7.2 Hz, 3 H, CH3), 1.13 (s, 9 H, CH3),
1 H, CH2), 3.55 (dd, J = 12.8, 5.2 Hz, 1 H, CH2), 3.90 (q, J = 1.19–1.43 (m, 6 H, CH2), 1.53–1.63 (m, 1 H, CH2), 1.70–1.80 (m,
5.6 Hz, 1 H, CH), 7.26–7.31 (m, 1 H, CH), 7.40 (td, J = 7.2, 1.2 Hz,
1 H, CH), 7.75 (dd, J = 8.0, 0.7 Hz, 1 H, CH), 7.83 (d, J = 8.0 Hz, 14.8, 3.2 Hz, 1 H, CH2), 4.19–4.27 (m, 1 H, CH), 7.59 (ddd, J =
1 H, CH) ppm. 13C NMR (100 MHz, CDCl3): δ = 14.3 (CH3), 22.8
7.8, 7.2, 1.2 Hz, 1 H, CH), 7.64 (ddd, J = 8.0, 7.2, 1.2 Hz, 1 H,
(CH2), 25.3 (CH2), 28.9 (CH3), 32.2 (CH2), 35.9 (CH2), 39.5 (CH2), CH), 8.02 (dd, J = 8.0, 2.2 Hz, 1 H, CH), 8.22 (d, J = 8.2 Hz, 1
70.1 (CH), 74.6 (C), 121.2 (CH), 121.5 (CH), 124.3 (CH), 126.2
H, CH) ppm. 13C NMR (100 MHz, CDCl3): δ = 14.2 (CH3), 22.7
1 H, CH2), 3.66 (dd, J = 14.6, 7.2 Hz, 1 H, CH2), 3.74 (dd, J =
(CH), 135.5 (C), 153.2 (C), 168 (C) ppm. MS (ESI+; H2O/CH3CN): (CH2), 24.8 (CH2), 28.5 (CH3), 31.9 (CH2), 37.0 (CH2), 60.8 (CH2),
m/z (%) = 338 (25) [M + H]+, 761 (100) [2M + Na]+. HRMS (ESI+;
H2O/CH3CN, 1:1): calcd. for C18H28NOS2 [M + H]+ 338.1612;
found 338.1607.
66.2 (CH), 75.2 (C), 122.5 (CH), 125.6 (CH), 127.8 (CH), 128.2
(CH), 136.9 (C), 152.9 (C), 167.1 (C) ppm. MS (ESI+; H2O/
CH3CN): m/z (%) = 392 (10) [M + Na]+, 761 (100) [2 M + Na]+.
HRMS (ESI+; H2O/CH3CN, 1:1): calcd. C18H27NO3S2Na [M +
Na]+ 392.1330; found 392.1337.
Methyl (S)-10-(Benzo[d]thiazol-2-ylthio)-9-tert-butoxydecanoate
(17c): According to the procedure described for 17a, 9c (552 mg,
1.50 mmol), Boc2O (3.27 g, 15.0 mmol), and Mg(ClO)4 (34 mg,
10 mol-%) were heated in refluxing anhydrous dichloromethane
Methyl (S)-10-(Benzo[d]thiazol-2-ylsulfonyl)-9-tert-butoxydecanoate
(18c): According to the procedure described for 18a, 17c (300 mg,
0.71 mmol), Mo7O4(NH3)6·4H2O (44 mg, 5 mol-%), and H2O2
(0.66 mL, 7.1 mmol) reacted in EtOH (25 mL) to give sulfone 18c
(8 mL) and gave 17c (460 mg, 72%) as a slightly yellow oil. [α]D
=
–19 (c = 0.15, CHCl ). IR (film): ν = 2943, 2923, 1726, 1464 cm–1.
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3
1H NMR (400 MHz, CDCl3): δ = 1.25 (s, 9 H, CH3), 1.26–1.50 (m, (204 mg, 63 %) as a slightly yellow oil. [α]D = –12.0 (c = 0.32,
8H CH2), 1.51–1.71 (m, 4 H, CH2), 2.29 (t, J = 7.8 Hz, 2 H, CH2), CHCl ). IR (film): ν = 2965, 2929, 1731, 1471 cm–1
.
1H NMR
˜
3
3.35 (dd, J = 12.2, 8.0 Hz, 1 H, CH2), 3.55 (dd, J = 12.2, 3.6 Hz, (400 MHz, CDCl3): δ = 1.13 (s, 9 H, CH3), 1.20–1.43 (m, 8 H, 4
1 H, CH2), 3.66 (s, 3 H, CH3), 3.89 (q, J = 7.8 Hz, 1 H, CH), 7.26–
CH2), 1.58–1.65 (m, 2 H, CH2), 1.69–1.81 (m, 1 H, CH2), 2.29 (t,
7.31 (m, 1 H, CH), 7.38–7.43 (m, 1 H, CH), 7.73–7.76 (m,1 H,
J = 7.8 Hz, 2 H, CH2), 3.61–3.78 (m, 5 H, CH3, CH2), 4.19–4.28
CH), 7.81–7.84 (m, 1 H, CH) ppm. 13C NMR (100 MHz, CDCl3): (m, 1 H, CH), 7.57–7.68 (m, 2 H, CH), 8.01–8.04 (m, 1 H, CH),
δ = 25.1 (CH2), 25.5 (CH2), 28.9 (CH3), 29.3 (CH2), 29.4 (CH2),
8.21–8.24 (m, 1 H, CH) ppm. 13C NMR (100 MHz, CDCl3): δ =
Eur. J. Org. Chem. 2013, 1716–1725
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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