Organometallics
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0.5%) for 1 h at room temperature. Thereafter, the blot was incubated
TLC: Rf (CyHex/EtOAc 1/1) = 0.74. 1H NMR (400 MHz,
CDCl3): δ 7.41−7.33 (m, 5H, CHAr), 7.28−7.19 (m, 5H, CHAr), 5.52
(d, J = 4.4 Hz, 1H, H2), 5.13−4.97 (m, 1H, H3), 3.14−3.00 (m, 1H,
H4), 2.37−2.23 (m, 1H, H6), 2.23−2.10 (m, 1H, H6), 1.90 (Ψddt, J =
15.2, 11.7, 3.5 Hz, 1H, H5), 1.75−1.65 (m, 1H, H5). 13C NMR (101
MHz, CDCl3): δ 210.7 (Fe(CO)3), 150.5 (CqAr), 129.8 (CHAr), 125.6
(CHAr), 120.2 (CHAr), 106.7 (C1), 79.6 (C2), 79.3 (C3), 59.6 (C4),
29.2 (C6), 24.2 (C5). 31P NMR (162 MHz, CDCl3): δ −16.73. FT-IR
overnight at 4 °C, either with polyclonal anti-VCAM-1 (R&D Systems,
Wiesbaden, Germany) or anti-HO-1 (Enzo Life Sciences, Lorrach,
̈
Germany). Subsequently the membrane was thoroughly washed with
TBS-Tween and incubated for 1 h at room temperature with the
appropriate horseradish peroxidase conjugated secondary antibody
(Jackson ImmunoResearch, Baltimore, MD). Proteins were visualized
using enhanced chemoluminescence technology according to the
manufacturer’s instructions (Pierce, Rockford, IL). To confirm equal
protein loading, membranes were reprobed with monoclonal anti-
GAPDH antibody (Abcam, Cambridge, U.K.).
(ATR): ν
̃
(cm−1) 3074 (w), 2946 (w), 2853 (w), 2045 (s, ν
(Fe(CO)3)), 1961 (bs, ν (Fe(CO)3)), 1588 (m), 1486 (s), 1380 (m),
1294 (m), 1216 (m), 1183 (s), 1163 (s), 1140 (m), 1104 (s), 1065
(m), 1007 (s), 945 (s), 896 (s), 752 (s) 686 (s). LR-MS (DIP-MS, 70
eV): m/z (%) 412 (3, [M − 2CO]+), 384 (5, [M − 3CO]+), 326 (8),
305 (10), 212 (13), 169 (10), 119 (12), 94 (37), 77 (100), 65 (66), 56
(13), 51 (43). HR-MS (DIP-MS, 70 eV): m/z 384.020 (calcd ([M −
3CO]+) m/z 384.021).
Syntheses. Synthesis of Phosphate Complexes of type rac-6 and
rac-7. General Procedures for the Desilylation/Phosphorylation
Sequence. Procedure A (Starting from TMS-Protected Dienol 11). A
solution of the silyloxydiene 11 (1.0 equiv) and Fe2(CO)9 (2.0 equiv)
in Et2O (concentration of the diene approximately 0.1 M) was heated
to reflux for 16 h. After evaporation of the solvent, the residue was
dissolved in THF (concentration of the theoretical amount of complex
approximately 0.2 M) and NaH (1.3 equiv) was added. The mixture
was cooled to 0 °C before a solution of TBAF in THF (1.3 equiv, 1.0
M in THF) was added. The reaction mixture was then stirred at 0 °C
for approximately 10 min until deprotection was complete (TLC
control). Subsequently, the chlorophosphate reagent (3.0 equiv) was
added and the reaction mixture was warmed to room temperature and
stirred for approximately 15 min (TLC control). Workup was initiated
by addition of aqueous saturated NH4Cl solution (20 mL), and the
mixture was extracted with MtBE (3 × 30 mL). The combined organic
phases were dried over MgSO4, and the solvent was evaporated. The
crude product was purified by column chromatography (CyHex/
EtOAc) to yield the desired complex.
(RS)-Tricarbonyl(η4 -1-dibenzylphosphoryloxy-1,3-
cyclohexadiene)iron(0) (rac-6d). Following general procedure B
(chromatography with CyHex/EtOAc 2/1), complex rac-6d (377
mg, 60%) was obtained as a yellow oil.
TLC: Rf (CyHex/EtOAc 1/1) = 0.63. 1H NMR (400 MHz,
CDCl3): δ 7.42−7.30 (m, 10H, CHAr), 5.52 (d, J = 4.1 Hz, 1H, H2),
5.16−4.98 (m, 5H, H7, H3), 3.04 (Ψs, 1H, H4), 2.24 (Ψdd, J = 18.8,
7.3 Hz, 1H, H6), 2.17−1.97 (m, 1H, H6), 1.87 (Ψtd, J = 11.8, 3.4 Hz,
1H, H5), 1.76−1.59 (m, 1H, H5). 13C NMR (101 MHz, CDCl3): δ
211.1 (Fe(CO)3), 135.6 (CqAr), 135.5 (CqAr), 128.5 (CHAr), 128.0
(CHAr), 127.9 (CHAr), 106.4 (C1), 79.4 (C2/C3), 79.2 (C2/C3), 69.6
(C7), 69.4 (C7), 59.5 (C4), 29.1 (C6), 24.1 (C5). 31P NMR (162
MHz, CDCl3): δ −5.86. FT-IR (ATR): ν
̃
(cm−1): 3020 (w), 2940 (w),
2884 (w), 2843 (w), 2043 (s, ν (Fe(CO)3)), 1960 (bs, ν (Fe(CO)3)),
1500 (w), 1454 (m), 1376 (m), 1325 (m), 1280 (m), 1213 (m), 1180
(w), 1141 (m), 1120 (m), 998 (s), 930 (m), 893 (s), 737 (m), 695 (s).
LR-MS (DIP-MS, 70 eV): m/z (%) 440 (<1, [M − 2CO]+), 412 (3,
[M − 3CO]+), 321 (8), 229 (3), 211 (2), 179 (3), 165 (3), 149 (5),
92 (8), 91 (100), 77 (12), 65 (21), 51 (11). HR-MS (DIP-MS, 70
eV): m/z 412.051 (calcd ([M − 3CO]+) m/z 412.0527).
Procedure B (Starting from rac-14 or rac-16). The reactions were
performed on a 1.0−2.5 mmol scale. A flask was charged with NaH
(1.3 equiv), and a solution of the (siloxydiene)Fe(CO)3 complex (rac-
14 or rac-16) in THF (1.0 equiv, approximately 0.06 M) was added.
The mixture was cooled to 0 °C before a solution of TBAF in THF
(1.3 equiv, 1.0 M in THF) was added. The mixture was stirred at 0 °C
for approximately 10 min until deprotection was complete (TLC
control). Subsequently, the chlorophosphate reagent (3.0 equiv) was
added and the mixture was warmed to room temperature and stirred
for approximately 15 min (TLC control). Workup was initiated by
addition of aqueous saturated NH4Cl solution (20 mL), and the
mixture was extracted with MtBE (3 × 30 mL). The combined organic
phases were dried over MgSO4, and the solvent was evaporated. The
crude product was purified by column chromatography (CyHex/
EtOAc) to yield the desired complex.
(RS)-Tricarbonyl(η4-1-bis(dimethylamino)phosphoryloxy-1,3-
cyclohexadiene)iron(0) (rac-6e). Following general procedure B
(chromatography with CyHex/EtOAc 2/1), complex rac-6e (120
mg, 51%) was obtained as a yellow oil that crystallized in the
refrigerator after some days.
TLC: Rf (EtOAc) = 0.18. 1H NMR (400 MHz, CDCl3): δ 5.55 (d, J
= 4.4 Hz, 1H, H2), 5.12−4.98 (m, 1H, H3), 2.99 (Ψdd, J = 3.9, 2.6
Hz, 1H, H4), 2.67, 2.65, 2.64, 2.63 (4 × s, 12H, H7), 2.19−2.08 (m,
2H, H6), 1.95−1.79 (m, 1H, H5), 1.77−1.63 (m, 1H, H5). 13C NMR
(101 MHz, CDCl3): δ 211.8 (Fe(CO)3), 107.0 (C1), 80.5 (C2), 78.9
(C3), 59.2 (C4), 36.4 (C7), 36.3 (C7), 36.3 (C7), 36.3 (C7), 29.5
(C6), 24.5 (C5). 31P NMR (162 MHz, CDCl3): δ 16.22. FT-IR
(RS)-Tricarbonyl(η4 -1-dimethylphosphoryloxy-1,3-
cyclohexadiene)iron(0) (rac-6b). Following general procedure B
(chromatography with CyHex/EtOAc 2/1), complex rac-6b (759
mg, 87%) was obtained as a yellow oil that crystallized in the
refrigerator after some days.
(ATR): ν
̃
(cm−1) 3446 (b w), 2943 (m), 2887 (m), 2841 (m), 2796
(w), 2036 (s, ν (Fe(CO)3)), 1948 (bs, ν (Fe(CO)3)), 1454 (m), 1382
(m), 1305 (m), 1224 (s), 1183 (m), 1138 (s), 1117 (s), 1066 (m), 977
(s), 851 (s), 754 (s), 708 (m), 608 (m). LR-MS (DIP-MS, 70 eV): m/
z (%) 314 (7, [M − 2CO]+), 286 (8, [M − 3CO]+), 284 (20), 269
(5), 241 (7), 229 (10), 184 (12), 163 (15), 149 (17), 135 (100), 121
(21), 94 (25), 92 (33), 77 (55), 65 (28), 56 (25), 51 (27). HR-MS
(DIP-MS, 70 eV): m/z 314.047 (calcd ([M − 2CO]+) m/z 314.0482).
Tm (CH2Cl2) = 43.7 °C.
TLC: Rf (CyHex/EtOAc 1/1) = 0.25. 1H NMR (600 MHz,
CDCl3): δ 5.46 (d, J = 4.3 Hz, 1H, H2), 4.98 (Ψt, J = 5.5 Hz, 1H, H3),
3.78−3.68 (m, 6H, H7), 3.01−2.89 (m, 1H, H4), 2.24−2.11 (m, 1H,
H6), 2.08−1.97 (m, 1H, H6), 1.86−1.74 (m, 1H, H5), 1.66−1.60 (m,
1H, H5). 13C NMR (126 MHz, CDCl3): δ 211.1 (Fe(CO)3), 106.1
(C1), 79.4 (C2), 79.2 (C3), 59.5 (C4), 54.5 (C7), 29.0 (C6), 24.1
̃
(C5). 31P NMR (202 MHz, CDCl3): δ −3.65. FT-IR (ATR): ν (cm−1)
(RS)-Tricarbonyl(η4 -1-dimethylphosphoryloxy-1,5-
cyclohexadiene)iron(0) (rac-7b). Following general procedure B
(chromatography with CyHex/EtOAc 2/1) complex rac-7b (792
mg, 91%) was obtained as a yellow oil (procedure A afforded the same
product in 43% yield).
3003 (w), 2954 (m), 2853 (m), 2042 (s, ν (Fe(CO)3)), 1961 (bs, ν
(Fe(CO)3)), 1456 (m), 1383 (m), 1329 (m), 1279 (s), 1183 (m),
1141 (s), 1122 (s), 1039 (s), 1003 (s), 929 (s), 893 (s), 849 (s), 776
(s), 698 (m), 642 (m), 611 (s). LR-MS (DIP-MS, 70 eV): m/z (%)
316 (3, [M − CO]+), 288 (8, [M − 2CO]+), 260 (18, [M − 3CO]+),
258 (45), 228 (15), 203 (100), 181 (13), 167 (32), 151 (25), 134
(27), 127 (54), 109 (85), 94 (33), 84 (30), 79 (52), 78 (63), 77 (70),
56 (45). HR-MS (DIP-MS, 70 eV): m/z 315.978 (calcd ([M − CO]+)
m/z 315.9799). Tm (CH2Cl2) = 29.3 °C.
TLC: Rf (CyHex/EtOAc 1/1) = 0.34. 1H NMR (400 MHz,
CDCl3): δ 5.65 (d, J = 6.6 Hz, 1H, H6), 4.02−3.78 (m, 6H, H7), 3.58
(dd, J = 5.1, 2.7 Hz, 1H, H2), 2.93−2.73 (m, 1H, H5), 1.86−1.67 (m,
2H, H3), 1.63−1.41 (m, 2H, H4). 13C NMR (101 MHz, CDCl3): δ
210.4 (Fe(CO)3), 129.8 (C1), 77.8 (C6), 56.9 (C2), 54.9 (C7), 51.2
(C5), 24.7 (C3), 23.1 (C4). 31P NMR (162 MHz, CDCl3): δ −3.64.
(RS)-Tricarbonyl(η4 -1-diphenylphosphoryloxy-1,3-
cyclohexadiene)iron(0) (rac-6c). Following general procedure A
(chromatography with CyHex/EtOAc 5/1), complex rac-6c (489
mg, 83%) was obtained as a yellow oil.
FT-IR (ATR): ν
̃
(cm−1): 3494 (b w), 3009 (w), 2956 (m), 2855 (m),
2042 (s, ν (Fe(CO)3)), 1960 (bs, ν (Fe(CO)3)), 1457 (s), 1427 (m),
5807
dx.doi.org/10.1021/om300359a | Organometallics 2012, 31, 5800−5809