The Journal of Organic Chemistry
Page 14 of 21
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(
m, 7H), 3.91 (dd, J = 10.2, 5.4 Hz, 1H), 3.83 (t, J = 10.2 Hz, 1H), 3.79 (d, J = 1.8 Hz, 1H), 3.17–
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.14 (m, 3H), 2.67–2.62 (m, 1H), 2.36 (dd, J = 14.4, 7.2 Hz, 1H), 2.15–2.10 (m, 1H), 1.89 (dd, J =
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3
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10.8, 6.0 Hz, 1H), 1.78–1.71 (m, 3H), 1.55 (m, 1H); C{ H} NMR (150 MHz, CDCl ): δ 140.5,
3
1
28.3, 128.2, 127.0, 101.9, 90.6, 69.4, 69.2, 62.6, 61.1, 59.0, 57.8, 45.4, 40.2, 39.8, 23.8, 22.5; IR
−
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(film): 3422, 3084, 2953, 2936, 2851, 1447, 1312, 1288, 1175, 1105, 1030, 1001, 818, 704 cm ;
+
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HRMS (ESI-TOF) m/z: [M + H] Calcd for C H FeNO 402.1520; Found 402.1514; m.p. 134.6–
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1
36.0 °C.
N-((R)-2-Hydroxy-1-phenethyl)-(S ,1S,R )-spiro[cyclopentadienyl tetrahydropentalenyl iron
p
a
(II)-1,2ʹ-pyrrolidine] (5b)
2
0
1
TLC (hexanes/ethyl acetate, 6:1 v/v): R = 0.13; [α] −214 (c 1.01, CHCl ); H NMR (600 MHz,
f
D
3
CDCl ): δ 7.48 (d, J = 7.8 Hz, 2H), 7.39 (t, J = 7.2 Hz, 2H), 7.29 (t, J = 7.2 Hz, 1H), 5.54 (dd, J =
3
9
.3, 5.7 Hz, 1H), 4.10–4.06 (m, 8H), 3.80 (t, J = 9.9 Hz, 1H), 3.63 (d, J = 1.8 Hz, 1H), 3.12–3.08
(m, 1H), 2.97 (td, J = 8.7, 4.2 Hz, 1H), 2.94 (s, 1H), 2.59 (dd, J = 14.4, 7.8 Hz, 1H), 2.40 (dd, J =
13
1
1
4.4, 7.8 Hz, 1H), 2.17–2.06 (m, 2H), 1.87–1.71 (m, 3H), 1.55 (m, 1H); C{ H} NMR (100 MHz,
CDCl ): δ 140.5, 128.3, 128.0, 126.8, 98.9, 91.9, 70.6, 69.6, 69.5, 62.7, 61.1, 59.6, 59.3, 45.3, 43.3,
3
38.8, 23.6, 22.9; IR (film) vmax 3422, 3088, 2953, 2940, 2851, 1491, 1447, 1375, 1306, 1288, 1229,
−1
+
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207, 1180, 1142, 1105, 1030, 883, 818, 746, 702, 459 cm ; HRMS (ESI-TOF) m/z: [M + H]
Calcd for C H FeNO 402.1520; Found 402.1514; m.p. 105.0–106.1 °C.
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Reduction of 3 by LiAlH4
A Schlenk tube was charged with 3 (1.02 g, 2 mmol) and anhydrous THF (20 mL). The mixture
was cooled to 0 °C. LiAlH (456 mg, 12.0 mmol) was added in portions at 0 °C. After that, the
4
mixture was stirred at 40 °C for 12 h. The mixture was cooled to 0 °C. 1 N NaOH (12 mL) was
added dropwise at 0 °C to quench the reaction. AcOEt was added and the mixture well stirred for
4
0 min. The mixture was filtered through Celite, and the filter cake washed with AcOEt. The filtrate
was dried over Na SO and concentrated. The residue was purified by column chromatography
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(20:1 hexanes/AcOEt) to afford 6 as orange solids (480 mg, 60% yield), 5a as a yellow liquid (128
mg, 16% yield) and 5b as an orange solid (132 mg, 16% yield).
Orange single crystals of 6a were obtained from a solution of 6a and 6b, which were inseparable
by silica gel chromatography.
(R ,1R,3ʹR,4ʹR,7ʹaS)-3ʹ-Phenyl-spiro[cyclopentadienyl tetrahydropentalenyl iron (II)-1,5ʹ-
p
hexahydropyrrolo[2,1-b]oxazole] (6a)
2
0
1
TLC (hexanes/ethyl acetate, 6:1 v/v): R = 0.60; [α] +105 (c 1.03, CHCl ); H NMR (600 MHz,
f
D
3
CDCl ): δ 7.54 (d, J = 7.8 Hz, 2H), 7.36 (t, J = 8.1 Hz, 2H), 7.23 (t, J = 7.5 Hz, 1H), 6.07 (t, J = 6.3
3
Hz, 1H), 4.98 (d, J = 4.2 Hz, 1H), 4.41 (t, J = 7.8 Hz, 1H), 4.18 (t, J = 1.8 Hz, 1H), 4.06 (d, J = 1.8
Hz, 1H), 3.98 (s, 5H), 3.83 (d, J = 1.8 Hz, 1H), 3.72 (dd, J = 8.4, 6.0 Hz, 1H), 2.63–2.58 (m, 1H),
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2.35–2.31 (m, 1H), 2.17–2.05 (m, 3H), 1.95–1.87 (m, 2H), 1.70–1.65 (m, 1H); C{ H} NMR (150
MHz, CDCl ): δ 144.9, 128.5, 126.5,125.7, 98.6, 97.1, 92.8, 74.3, 71.4, 70.3, 69.4, 62.6, 61.3, 60.1,
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4.3, 37.5, 29.0, 23.5; IR (film) vmax 3084, 3023, 2937, 2853, 1719, 1601, 1493, 1449, 1373, 1308,
−
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287, 1163, 1132, 1105, 1074, 1043, 1024, 1001, 820, 806, 735, 702, 662, 505, 478, 461 cm ;
+
HRMS (ESI-TOF) m/z: [M + H] Calcd for C H FeNO 400.1364; Found 400.1358; m.p. 117.8–
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1
19.5 °C.
Sp,1S,3ʹR,4ʹR,7ʹaS)-3ʹ-Phenyl-spiro[cyclopentadienyl tetrahydropentalenyl iron (II)-1,5ʹ-
hexahydropyrrolo[2,1-b]oxazole] (6b)
TLC (hexanes/ethyl acetate, 6:1 v/v): R = 0.60; [α] −180 (c 1.00, CHCl ); H NMR (400 MHz,
(
20
1
f
D
3
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