Organometallics
Article
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MHz, CDCl3) δ 10.23 (s, 1H), 7.74−7.68 (m, 4H), 7.65 (d, 3JHH = 8.6
30 v/v) to give the product as a colorless oil (0.35 g, 90%). H NMR
Hz, 1H), 7.48−7.43 (m, 2H), 7.42−7.36 (m, 4H), 6.47 (ddd, JHH
=
=
(601 MHz, CDCl3) δ 7.20−7.13 (m, 1H), 6.50−6.38 (m, 3H), 5.74−
4
3
3
3
8.6, 2.2, 0.7 Hz, 1H), 6.18 (d, JHH = 2.1 Hz, 1H), 4.08 (sept, JHH
5.63 (m, 1H), 4.47 (sept, JHH = 6.0 Hz, 1H), 3.93 (t, JHH = 6.5 Hz,
2H), 2.75−2.46 (bs, 6H), 2.45−2.39 (m, 2H), 2.35 (s, 3H), 1.87−1.79
(dd, JHH = 7.1, 1.8 Hz, 3H), 1.79−1.69 (m, 2H), 1.59−1.50 (m, 2H),
1.48−1.39 (m, 2H), 1.35−1.24 (m, 16H). 13C NMR (126 MHz,
CDCl3) δ 159.2, 156.7, 130.6, 125.3, 124.9, 120.5, 105.0, 102.0, 71.0,
68.2, 58.9, 55.1, 53.2, 46.1, 29.6, 29.5, 29.5, 27.7, 26.9, 26.2, 22.3, 14.9.
HRMS (ESI - TOF) m/z: [M + H]+ Calculated for C26H45N2O2
417.3481; Found 417.3478.
6.1 Hz, 1H), 1.12 (s, 9H), 1.12 (d, 3JHH = 6.0 Hz, 6H). 13C NMR (126
MHz, CDCl3) δ 188.9, 162.6, 162.1, 135.5, 132.3, 130.4, 129.9, 128.2,
120.1, 112.9, 105.2, 71.0, 26.6, 21.8. HRMS (ESI - TOF) m/z: [M +
Na]+ Calculated for C26H30O3NaSi 441.1862; Found 441.1851.
tert-Butyl(3-isopropoxy-4-(prop-1-en-1-yl)phenoxy)diphenylsi-
lane 9. Potassium tert-pentoxide solution in toluene (35.3 mL, 1.7 M,
59.9 mmol, 1.3 equiv) was added dropwise to a mixture of 4-((tert-
butyldiphenylsilyl)oxy)-2-isopropoxybenzaldehyde (19.3 g, 46.1 mmol,
1 equiv) and ethyltriphenylphosphonium bromide (23.1 g, 62.2 mmol,
1.3 equiv) in toluene (230 mL) at −20 °C over 30 min. The mixture
was brought to rt and stirred for an additional 30 min. After removal of
the solvents in vacuo, water was added (100 mL) and the mixture was
extracted with cyclohexane (3 × 60 mL). Combined organic phases
were dried over sodium sulfate, filtered, and concentrated in vacuo.
The product was isolated by chromatography on silica gel with
cyclohexane/ethyl acetate (95/5 v/v) as eluent (white solid, 11.1 g,
56% yield). 1H NMR (500 MHz, CDCl3) δ 7.77−7.71 (m, 4H), 7.60−
Complex 15. Potassium tert-pentoxide solution in toluene (1.7 M,
1.4 mL, 1.1 equiv) was added to a suspension of 1,3-bis(2,6-
diisopropylphenyl)-4-((4-ethylpiperazin-1-yl)methyl)-4,5-dihydro-1H-
imidazol-3-ium tetrafluoroborate salt (1.5 g, 2.48 mmol, 1.15 equiv) in
toluene (27 mL) and stirred for 30 min at rt under argon. The
suspension was heated up to 80 °C and stirred for 10 min. Umicore
M10TM (1.91 g, 2.15 mmol, 1 equiv) was added, and the reaction
mixture was stirred at 80 °C for an additional 20 min. Then the
mixture was cooled down to 60 °C and 1-(9-(3-isopropoxy-4-(prop-1-
en-1-yl)phenoxy)nonyl)-4-methylpiperazine (0.81 g, 1.9 mmol, 0.9
equiv) was added, followed by addition of copper(I) chloride (0.53 g,
5.4 mmol, 2.5 equiv). The resulting mixture was stirred for an
additional 20 min at 60 °C. The mixture was cooled to room
temperature and filtered through silica gel with cyclohexane/ethyl
acetate (80:20 v/v), followed by ethyl acetate/trimethylamine (98:2 v/
v). The green filtrate was concentrated in vacuo to yield 0.49 g of the
product (green solid, 21% yield). Due to its limited stability, the
product was used immediately in the following step. TLC (SiO2) Rf =
0.25, AcOEt/TEA 98:2 v/v. 1H NMR (500 MHz, CD2Cl2) δ 15.92 (s,
1H, Ru = CH), 7.60−7.57 (m, 1H), 7.48−7.45 (m, 1H), 7.41−7.39
(m, 2H), 7.35−7.32 (m, 2H), 6.71 (d, 3JHH = 8.0 Hz, 1H), 6.40−6.37
(m, 2H), 4.84 (sept, 3JHH = 6.0 Hz, 1H, (CH3)2CH-O), 4.47−4.37 (m,
1H, ArNCH), 4.32−4.28 (m, 1H, ArNCH), 4.19−4.15 (m, 1H,
3
3
7.20 (m, 6H), 7.15 (d, JHH = 8.5 Hz, 0.4H), 7.05 (d, JHH = 8.3 Hz,
0.6H), 6.59−6.52 (m, 0.3H), 6.44−6.36 (m, 1.6H), 6.28−6.17 (m,
3
1H), 6.11−5.95 (m, 0.4H), 5.71−5.63 (m, 0.6H), 4.04 (sept, JHH
=
6.0 Hz, 1H), 1.84 (dd, JHH = 6.6, 1.7 Hz, 1H), 1.79 (dd, JHH = 7.1, 1.8
Hz, 2H), 1.14−1.09 (m, 15H). 13C NMR (126 MHz, CDCl3) δ 156.2,
155.5, 135.8, 135.7, 135.7, 135.4, 133.3, 130.4, 130.0, 130.0, 129.4,
127.9, 127.4, 125.2, 124.9, 120.7, 111.3, 106.3, 70.6, 26.7, 22.1, 14.9.
HRMS (ESI - TOF) m/z: [M + H]+ Calculated for C28H35O2Si
431.2406; Found 431.2395.
3-Isopropoxy-4-(prop-1-en-1-yl)phenol 10. Potassium carbonate
(7.1 g, 51.6 mmol, 2 equiv) was added to a solution of tert-butyl(3-
isopropoxy-4-(prop-1-en-1-yl)phenoxy)diphenylsilane (11.1 g, 25.8
mmol, 1 equiv) in acetonitrile/water (115 mL, 10% water), and the
mixture was stirred at 70 °C for 4 h. The suspension was diluted with
water, and acidified with 5% HCl, and the mixture was extracted with
dichloromethane (3 × 50 mL). Combined organic phases were dried
over sodium sulfate, filtered, and concentrated in vacuo. The product
(3.0 g, yellow oil, 61% yield, unstable) was purified by chromatography
on silica gel with cyclohexane/ethyl acetate (10−30%) as eluent and
used immediately in the following step.
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ArNCH), 3.91 (t, JHH = 6.5 Hz, 2H, CHCH2N), 3.81−3.69 (bs, 1H,
(CH3)2CHAr), 3.68−3.57 (bs, 1H, (CH3)2CHAr), 3.53−3.38 (m, 1H,
3
(CH3)2CHAr), 3.29 (sept, JHH = 6.5 Hz, 1H(CH3)2CHAr), 2.71 (t,
3JHH = 11.5 Hz, 1H), 2.60−2.25 (m, 20H), 2.21 (s, 3H), 1.76−1.71
(m, 2H), 1.48- 1.38 (m, 10H), 1.35−1.20 (m, 30H), 1.12−1.04 (m,
2H), 0.98 (t, JHH = 6.5, 3H), 0.92−0.86 (m, 2H). 13C NMR (126
3
MHz, CD2Cl2) δ 288.5, 217.1, 161.8, 154.7, 150.0, 139.7, 130.2, 130.0,
125.5, 123.9, 107.3, 101.5, 75.7, 69.2, 61.3, 60.5, 59.2, 55.8, 53.8, 53.3,
52.7, 46.4, 30.1, 29.8, 29.7, 28.4, 28.1, 27.5, 26.5, 25.9, 22.2, 22.0, 12.4.
HRMS: two independent, specialized laboratories were not able to
measure the molecular ion for complex 15. The best attempt allowed
for measurement of a complex with a partially fragmented piperazine
ring.
4-((9-Bromononyl)oxy)-2-isopropoxy-1-(prop-1-en-1-yl)benzene
11. Diisopropyl azodicarboxylate (3.72 mL, 18.9 mmol, 1.1 equiv) was
added dropwise at −20 °C to a mixture of 3-isopropoxy-4-(prop-1-en-
1-yl)phenol (3.30 g, 17.2 mmol, 1.0 equiv), 9-bromo-1-nonanol (4.02
g, 18.0 mmol, 1.05 equiv), and triphenylphosphine (4.95 g, 18.9 mmol,
1.1 equiv) in dry dichloromethane (80 mL). After 1 h, the reaction
mixture was allowed to warm up to room temperature and stirred for 1
h, then concentrated. Water (50 mL) was added, and the mixture was
extracted with cyclohexane (3 × 50 mL). Combined organic phases
were dried over sodium sulfate and filtered. After evaporation of the
solvents, the crude product was purified by column chromatography
(silica gel, cyclohexane/ethyl acetate, 98/2 v/v) to give the product as
IR (film, cm−1) 2962, 2922, 2853, 2812, 2768, 1677, 1597, 1463,
1441, 1382, 1323, 1256, 1187, 1611, 1103, 1014, 803.
Catalyst 1. Ruthenium complex 15 (450 mg, 0,42 mmol, 1 equiv)
was placed in a pressure reactor and dissolved in dry isopropanol (10
mL). Cooled −30 °C liquid chloromethane (4.21 g, 84.0 mmol, 200
equiv) was added, the tube was sealed, and the mixture was stirred at
50 °C for 48 h. The reaction mixture was concentrated in vacuo, and
the crude residue was purified by filtration through neutral aluminum
oxide with dichloromethane/methanol (90:10 v/v) as eluent. The
product (green solid) was obtained in 61% yield. TLC (Al2O3) Rf =
0.2, DCM/MeOH 9:1 v/v.1H NMR (500 MHz, CD2Cl2) δ 15.86 (s,
1H, RuCH), 7.62−7.59 (m, 1H), 7.49−7.46 (m, 1H), 7.42−7.40
(m, 2H), 7.35−7.32 (m, 2H), 6.71 (d, 3JHH = 8.0 Hz, 1H), 6.40−6.37
(m, 2H), 4.84 (sept, 3JHH = 6.0 Hz, 1H, (CH3)2CH-O), 4.43−4.30 (m,
2H, ArNCH2), 4.18 (t, 3JHH = 9.0 Hz, 1H, ArNCH), 3.91 (t, 3JHH = 6.5
Hz, 2H,CHCH2N), 3.84 (sept, 3JHH = 6.5 Hz, 2H, 2 × (CH3)2CHAr),
3.78−3.71 (m, 2H), 3.67−3.56 (m, 6H), 3,46 (s, 6H, N+(CH3)2), 3.37
(d, 3JHH = 5.0 Hz, 1 H), 3.32 (s, 3H, N+CH3), 3.26 (quint, 3JHH = 6.5
Hz, 1H), 2.84−2.59 (m, 10H), 2.43−2.40 (m, 2H), 1.76−1.70 (m,
2H), 1.47−1.39 (m, 7H), 1.37−1.17 (m, 35H), 1.11−1.01 (m, 3H),
0.93−0.75 (m, 2H). 13C NMR (126 MHz, CD2Cl2) δ 288.7, 218.2,
161.8, 154.7, 149.7, 139.6, 130.3, 130.2, 125.6, 123.9, 107.3, 101.5,
75.8, 69.1, 62.6, 60.0, 57.9, 47.4, 29.9, 29.8, 29.7, 29.6, 28.3, 27.6, 27.1,
26.4, 25.9, 22.2, 21.9, 8.1.
a colorless oil (3.9 g, 57%). 1H NMR (500 MHz, CDCl3) δ 7.21−7.17
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(m, 1H), 6.51−6.36 (m, 3H), 5.76−5.62 (m, 1H), 4.48 (sept, JHH
=
6.0 Hz, 1H), 4.02−3.85 (m, 2H), 3.44−3.37 (m, 2H), 1.91−1.81 (m,
5H), 1.81−1.71 (m, 2H), 1.49−1.41 (m, 4H), 1.38−1.30 (m, 12H).
13C NMR (126 MHz, CDCl3) δ 159.2, 156.7, 130.6, 125.3, 124.9,
120.5, 105.0, 102.0, 71.0, 68.1, 34.1, 33.0, 29.5, 29.5, 29.4, 28.8, 28.3,
26.2, 22.4, 14.9. HRMS (ESI - TOF) m/z: [M + H]+ Calculated for
C21H34O2Br 397.1742; Found 397.1729.
1-(9-(3-Isopropoxy-4-(prop-1-en-1-yl)phenoxy)nonyl)-4-methyl-
piperazine 12. Potassium carbonate (0.142 g, 1.02 mmol, 1.1 equiv)
and 1-methylpiperazine (0.187 g, 1.86 mmol, 2.0 equiv) were added to
a solution of 4-((9-bromononyl)oxy)-2-isopropoxy-1-(prop-1-en-1-
yl)benzene (0.370 g, 0.93 mmol, 1.0 equiv) in acetonitrile (4.8 mL).
The suspension was stirred at 80 °C for 4 h, then cooled to rt. The
solvents were removed in vacuo, and the residue was resuspended in
dichloromethane (10 mL) and filtered through a Schott funnel. The
mixture was concentrated in a rotary evaporator and purified by
column chromatography (silica gel, DCM/MeOH gradient up to 70/
F
Organometallics XXXX, XXX, XXX−XXX