1H, H3), 2.89–2.78 (m, 1H, H4), 2.28–2.10 (m, 1H, H6),
2.06–1.81 (m, 2H, H5, H6), 1.68–1.75 (m, 1H, H5), 1.09 (s,
21H, H7, H8). 13C NMR (75 MHz, CDCl3): δ 213.3 (Fe(CO)3),
113.9 (C1), 78.1 (C2), 76.0 (C3), 56.7 (C4), 31.0 (C6), 24.6
(C5), 18.0 (C8), 13.2 (C7). LR-MS (DIP-MS, 70 eV): m/z (%) =
392 (1, [M]+), 364 (32, [M − CO]+), 336 (9, [M − 2CO]+),
334 (25), 308 (7, [M − 3CO]+), 306 (95), 290 (15), 265 (17),
264 (100), 252 (16), 248 (21), 222 (33), 207 (15), 179 (15),
164 (11), 151 (20), 137 (17), 121 (5), 100 (5). HR-MS
(DIP-MS, 70 eV): m/z 364.116 (calcd ([M − CO]+): m/z
364.1157).
310 (17), 309 (28), 254 (18), 240 (22), 198 (15), 156 (8), 149
(21), 134 (14), 97 (12), 96 (40), 57 (33), 56 (22, [Fe]+). HR-MS
(DIP-MS, 70 eV): m/z 446.2115 0.0004 (calcd ([M − CO]+):
m/z 446.2119).
(RS)-Tricarbonyl-η4-(1-acetoxy-3,3-dimethyl-1,5-cyclohexadiene)-
iron(0) (rac-12). Yield: 525 mg (1.72 mmol, 57%). mp 54.1 °C
(from DCM). EA: Calcd for C13H14FeO5: C 51.01; H 4.61.
Found: C 51.00; H 4.65. FT-IR (ATR): ν [cm−1] = 2953 (m,
C
sp3–H), 2866 (w, Csp3–H), 2043 (s, Fe(CO)3), 1961 (bs,
1
Fe(CO)3), 1767 (s, CvO). H NMR (600 MHz, CDCl3): δ =
5.62 (d, J = 6.0 Hz, 1H, H6), 3.07 (Ψd, J = 2.0 Hz, 1H, H2),
2.75–2.72 (m, 1H, H5), 2.17 (s, 3H, H8), 1.56–1.41 (m, 2H,
H4), 1.08 (s, 3H, H9/H10), 1.03 (s, 3H, H9/H10). 13C NMR
(150 MHz, CDCl3): δ = 211.0 (Fe(CO)3), 169.7 (C7), 126.6
(C1), 81.1 (C6), 71.1 (C2), 51.4 (C5), 42.1 (C4), 36.1 (C3), 34.6
(C9/C10), 30.8 (C9/C10), 21.2 (C8). LR-MS (DIP-MS, 70 eV):
m/z (%) = 278 (12, [M − CO]+), 250 (26, [M − 2CO]+), 222
(24, [M − 3CO]+), 206 (100), 178 (12), 164 (19), 146 (9), 134
(10), 109 (17), 97 (24), 91 (14), 71 (8), 68 (12), 56 (57, [Fe]+).
(RS)-Tricarbonyl-η4-(1-triisopropylsiloxy-1,5-cyclohexadiene)-
iron(0) (rac-35). Yield: 2.85 g (7.28 mmol, 92%). FT-IR (ATR):
ν [cm−1] = 2944 (s, Csp3–H), 2889 (m, Csp3–H), 2865 (s, Csp3
–
H), 2040 (s, Fe(CO)3), 1960 (bs, Fe(CO)3). 1H NMR (300 MHz,
CDCl3): δ = 5.28 (d, J = 6.5 Hz, 1H, H6), 3.39 (Ψs, 1H, H2),
2.70 (d, J = 2.7 Hz, 1H, H6), 1.84–1.62 (m, 2H, H3),
1.48 (Ψddd, J = 19.3, 14.4, 9.0 Hz, 2H, H4), 1.22 (Ψdd, J =
14.4, 6.9 Hz, 3H, H7), 1.11 (s, 18H, H8). 13C NMR (75 MHz,
CDCl3): δ = 211.6 (Fe(CO)3), 136.5 (C1), 76.7 (C6), 58.6 (C2),
50.5 (C5), 25.4 (C3), 23.1 (C4), 17.7 (C8), 12.4 (C7). LR-MS
(DIP-MS, 70 eV): m/z (%) = 392 (2, [M]+), 364 (31, [M −
CO]+), 336 (9, [M − 2CO]+), 334 (30), 308 (14, [M − 3CO]+),
306 (100), 290 (30), 265 (17), 264 (98), 252 (5), 248 (19), 222
(45), 207 (15), 179 (15), 164 (25), 151 (10), 137 (15), 121 (9),
100 (5). HR-MS (DIP-MS, 70 eV): m/z 364.115 0.0004 (calcd
([M − CO]+): m/z 364.1157).
HR-MS (DIP-MS, 70 eV): m/z 278.0145
0.0004 (calcd
([M − CO]+): m/z 278.0241).
(RS)-Tricarbonyl-η4-(1-acetoxy-4,4-dimethyl-1,5-cyclohexadiene)-
iron(0) (rac-11). Yield: 659 mg (2.15 mmol, 72%). mp 44.7 °C
(from DCM). EA: Calcd for C13H14FeO5: C 51.01; H 4.61.
Found: C 51.27; H 4.69. FT-IR (ATR): ν [cm−1] = 2995 (m,
C
sp3–H), 2859 (w, Csp3–H), 2043 (s, (Fe(CO)3), 1967 (bs,
1
Fe(CO)3), 1762 (s, CvO). H NMR (500 MHz, CDCl3): δ =
5.45 (Ψdd, J = 1.9, 6.6 Hz, 1H, H6), 3.20 (dd, J = 2.7, 4.9 Hz,
1H, H2), 2.50 (d, J = 6.3 Hz, 1H, H5), 2.18 (s, 3H, H10),
1.78 (dd, J = 2.8, 14.9 Hz, 1H, H3), 1.6 (dd, J = 3.0, 14.9 Hz,
1H, H3), 1.00 (s, 3H, H7/H8), 0.96 (s, 3H, H7/H8). 13C NMR
(125 MHz, CDCl3): δ = 210.9 (Fe(CO)3), 170.2 (C9), 128.8
(C1), 76.7 (C6), 65.1 (C5), 58.2 (C2), 43.0 (C3), 34.7 (C4),
34.2 (C7/C8), 30.7 (C7/C8), 21.0 (C9). LR-MS (DIP-MS,
70 eV): m/z (%) = 278 (5, [M − CO]+), 250 (15, [M − 2CO]+),
222 (3, [M − 3CO]+), 206 (100), 178 (12), 164 (20), 146 (11),
134 (9), 119 (10), 109 (17), 97 (24), 91 (20), 83 (28), 71 (43),
69 (43), 57 (81), 56 (57, [Fe]+). HR-MS (DIP-MS, 70 eV): m/z
278.024 0.0011 (calcd ([M − CO]+): m/z 278.0241).
(RS)-Tricarbonyl-η4-(1-hexadecanoyloxy-1,3-cyclohexadiene)-
iron(0) (rac-18). A solution of TBAF (2.5 mL, 3.00 mmol,
1.2 M in THF, 3.5 equiv.) was added to a solution of complex
rac-38 (333 mg, 0.85 mmol, 1 equiv.) in DMF (10 mL) and the
mixture was stirred (10 min, TLC). Afterwards DIPEA
(0.51 mL, 3.0 mmol, 3.5 equiv.) was added, followed by the
addition of palmitoyl chloride (0.91 mL, 3.0 mmol, 3.5 equiv.).
After stirring at 20 °C to completion (10 min, TLC), the reaction
was quenched by the addition of water and extracted with
hexane and MtBE. The combined organic solvents were dried
over MgSO4 and evaporated. After purification by column
chromatography (DCM–CyHex = 1 : 3), 393 mg (0.83 mmol,
97%) of complex rac-18 were isolated as a yellow solid. mp
29.5 °C (from DCM). EA: Calcd for C25H38FeO5: C 63.29;
H 8.07. Found: C 63.45; H 8.08. FT-IR (ATR): ν [cm−1] = 2920
(s, Csp3–H), 2850 (s, Csp3–H), 2046 (s, Fe(CO)3), 1962 (bs,
(RS)-Tricarbonyl-η4-(1-acetoxy-5,5-dimethyl-1,3-cyclohexadiene)-
iron(0) (rac-13). Yield: 525 mg (1.72 mmol, 57%). EA: Calcd
for C13H14FeO5: C 51.01; H 4.61. Found: C 50.81; H 4.94.
FT-IR (ATR): ν [cm−1] = 2957 (m, Csp3–H), 2860 (w, Csp3–H),
2044 (s, Fe(CO)3), 1962 (bs, Fe(CO)3), 1752 (s, CvO).
1H NMR (500 MHz, CDCl3): δ = 5.40–5.35 (m, 1H, H2),
5.07 (dd, J = 4.5, 6.5 Hz, 1H, H3), 2.76 (Ψdd, J = 1.0, 6.5 Hz,
1H, H4), 2.20–2.10 (m, 1H, H6), 2.02 (s, 3H, H8), 1.76–1.70
(m, 1H, H6), 1.09 (s, 3H, H9/H10), 0.96 (s, 3H, H9/H10).
13C NMR (125 MHz, CDCl3): δ = 169.7 (C7), 101.9 (C1), 81.3
(C2), 77.4 (C3), 72.6 (C4), 44.9 (C6), 34.9 (C9/C10), 30.9
(C9/C10), 20.9 (C8). LR-MS (DIP-MS, 70 eV): m/z (%) = 306
(1, [M]+), 278 (12, [M − CO]+), 250 (36, [M − 2CO]+), 222
(29, [M − 3CO]+), 206 (100), 178 (12), 164 (15), 146 (11), 134
(9), 119 (10), 91 (11), 83 (28), 71 (9), 56 (26, [Fe]+). HR-MS
(DIP-MS, 70 eV): m/z 278.021 0.0001 (calcd ([M − CO]+):
m/z 278.0241).
1
Fe(CO)3), 1748 (s, CvO). H NMR (500 MHz, CDCl3): δ =
5.39 (d, J = 4.3 Hz, 1H, H2), 5.21–5.06 (m, 1H, H3), 3.11 (ddd,
J = 5.5, 3.8, 1.8 Hz, 1H, H4), 2.32 (t, J = 7.6 Hz, 2H, H8), 2.17
(ddd, J = 12.6, 3.0, 1.6 Hz, 1H, H6), 1.89 (ddt, J = 15.0, 11.6,
3.4 Hz, 1H, H5), 1.84–1.75 (m, 1H, H6), 1.75–1.66 (m, 1H,
H6), 1.63 (dd, J = 14.2, 7.3 Hz, 2H, H21), 1.36–1.23 (m, 24H,
H9–H20), 0.90 (t, J = 6.9 Hz, 3H, H22). 13C NMR (126 MHz,
CDCl3): δ = 211.3 (Fe(CO)3), 172.0 (C7), 103.2 (C1), 80.5
(C3), 80.3 (C2), 60.2 (C4), 34.5 (C8), 31.9 (C9–C20), 29.7 (C9–
C20), 29.7 (C9–C20), 29.6 (C9–C20), 29.6 (C9–C20), 29.4
(C9–C20), 29.4 (C9–C20), 29.2 (C9–C20), 29.0 (C9–C20), 26.7
(C6), 24.8 (C21), 24.0 (C5), 22.7 (C9–C20), 14.1 (C22).
LR-MS (DIP-MS, 70 eV): m/z (%) = 446 (2, [M − CO]+),
418 (6, [M − 2CO]+), 390 (100, [M − 3CO]+), 362 (4), 334 (6),
This journal is © The Royal Society of Chemistry 2012
Dalton Trans., 2012, 41, 13862–13875 | 13873