Angewandte
Chemie
from tetramethylsilane (TMS) referenced to residual solvent 1H
signals. 11B NMR, 19F NMR, and 31P NMR spectra were calibrated
and reported downfield from external BF3·OEt2, CFCCl3,and H3PO4,
respectively. Mass spectrometric analyses were obtained using a
VG70 magnetic sector instrument. Elemental analyses were per-
formed by Analytic Lab, Marine Science Institute, University of
California, Santa Barbara.
4: Compound 2 (52.6 mg, 0.10 mmol) and two equivalents of
B(C6F5)3 (102 mg, 0.20 mmol) were mixed in C6H6 (4.0 g). The color
of the solution changed from orange to red immediately along with
the formation of white precipitate. After stirring for 1 h, hexane
(1.0 g) was added to the mixture and the reaction mixture was filtered
after 15 min. The C6H6 and hexane were removed from the filtrate
under vacuum, which gave a red solid product (91 mg, 94% yield).
1H NMR (400 MHz, C6D6, 258C): d = 7.27 (t, J = 7.6 Hz, 1H; benzyl-
ph-H4), 7.00 (t, J = 7.6 Hz, 1H; imine-ph-H4), 6.96 (d, J = 7.4 Hz, 2H;
imine-ph-H3,5), 6.90 (t, J = 7.6, 2H; benzyl-ph-H3,5), 6.26 (d, J =
7.0 Hz, 2H; benzyl-ph-H2,6), 2.88 (septet, J = 6.8 Hz, 2H; iPr-CH),
2.01 (br s, 3H; CH3 in acetyl), 1.80 (s, 3H; CH3), 1.48 (br s, 3H; CH3-
CO-B(C6F5)3), 1.31 (d, J = 6.8 Hz, 6H; iPr-CH3), 0.96 (s, 2H; benzyl-
CH2), 0.85 ppm (d, J = 6.8 Hz, 6H; iPr-CH3); 13C NMR (50 MHz,
C6D6, 258C): d = 184.93, 174.46, 151.30, 146.48, 140.41, 138.76, 138.05,
135.41, 129.59, 125.05 and 116.25 (carbonyl, imine and ph-C), 107.94
(ethylene), 31.06, 29.27 and 25.07 (CH3 in acetyl, CH3-CO-B(C6F5)3
and CH3), 28.61 (iPr-CH), 24.89 (iPr-CH3), 24.09 (iPr-CH3),
23.46 ppm (benzyl-CH2); 19F NMR (C6D6, 376 MHz, 258C): d =
À133.79, À158.13, À164.29 ppm; 11B NMR (C6D6, 161 MHz, 258C):
d = À13.25 ppm; Elemental analysis calcd (%) for C44H33NO2BF15Ni:
C 54.92, H 3.46, N 1.46; found: C 53.71, H 3.51, N 1.45.
6: Compound 6 was prepared in 90% yield from potassium 4-
(2,6-diisopropylphenylimino)acetylacetonate by the same method for
preparing 2. 1H NMR (400 MHz, C6D6, 258C): d = 7.90 (d, J = 7.2 Hz,
2H; benzyl-ph-H2,6), 7.08–6.97 (m, 6H; imine-ph-H and benzyl-ph-
H3,4,5), 5.13 (s, 1H; CH), 4.07 (septet, J = 6.8 Hz, 2H; iPr-CH), 1.81 (s,
3H; CH3), 1.59 (s, 3H; CH3), 1.40 (d, J = 6.8 Hz, 6H; iPr-CH3), 1.21
(d, J = 7.2 Hz, 6H; iPr-CH3), 0.81 (s, 2H; benzyl-CH2), 0.66 ppm (d,
J = 9.6 Hz, 9H; PCH3); 13C NMR (100 MHz, C6D6, 258C): d = 176.42
(carbonyl), 166.02 (imine), 147.79, 142.16, 130.36, 127.99, 126.01,
124.02, 123.60, 123.60 (ph-C), 98.29 (ethylene), 28.63 (iPr-CH), 26.64
(CH3), 26.02 (CH3), 25.07 (iPr-CH3), 24.86 (iPr-CH3), 12.55 (d, J =
26 Hz, PCH3), 10.04 ppm (d, J = 24 Hz, benzyl-CH2); 31P NMR
(162 MHz, C6D6, 258C): d = À13.26 ppm; Elemental analysis calcd
(%) for C27H40NOPNi: C 66.96, H 8.33, N 2.89; found: C 67.56, H
8.51, N 3.02.
7: B(C6F5)3 (153 mg, 0.30 mmol) in toluene (2 g) was added to 6
(145 mg, 0.30 mmol) in toluene (2 g). The color of solution changed
from orange to dark red, and a white precipitate formed after several
minutes. After stirring for 1 h, 1 g hexane was added to the mixture
and the reaction mixture was filtered after 15 min. Solvents were
removed from the filtrate under vacuum and the residue was
extracted with hexane (1 g). The hexane was removed under
vacuum to afford 114 mg of 7 in 93% yield. 1H NMR (400 MHz,
C6D6, 258C): d = 7.46 (tt, J = 7.6 Hz, 1H; benzyl-ph-H4), 7.08–7.05 (m,
5H; imine-ph-H and benzyl-ph-H3,5), 6.68 (dd, J = 8.0 Hz, 2H;
benzyl-ph-H2,6), 4.85 (s, 1H; CH), 3.85 (septet, J = 6.8 Hz, 2H; iPr-
CH), 1.70 (s, 3H; CH3), 1.42 (d, J = 6.8 Hz, 6H; iPr-CH3), 1.41 (s, 3H;
CH3), 1.13 (d, J = 6.8 Hz, 6H; iPr-CH3), 0.70 ppm (s, 2H; benzyl-
CH2); 13C NMR (100 MHz, C6D6, 258C): d = 178.30 (carbonyl),
165.22 (imine), 151.91, 140.10, 134.91, 127.62, 125.67, 124.05, 116.92,
107.65 (ph-C), 97.71 (ethylene), 28.88 (CH3), 28.56 (iPr-CH), 27.09
(CH3), 24.68 (iPr-CH3), 24.53 (iPr-CH3), 23.06 ppm (benzyl-CH2);
Elemental analysis calcd (%) for C24H31NONi: C 70.62, H 7.65, N
3.43; found: C 70.42, H 7.53, N 3.48.
Typical reaction with ethylene: Compound 4 (5 mmol) in toluene
(0.50 g) was added to a 70-mL glass reactor charged with toluene
(27.50 g). The reactor was assembled and brought out of the glove
box. After stirring the solution at 308C for 2 min, ethylene was fed
continuously for 20 min under a pressure of 100 psi (689.476 kPa).
The reaction was quenched by release of ethylene pressure and
addition of acetone (1 mL). The solvent was removed to afford a
viscous oil, which was further dried under high vacuum overnight. The
yield was measured by weighing the viscous oil or by weighing the
1: 3-(1-hydroxyethylidene)-2,4-pentanedione (1.02 g, 7.2 mmol),
2,6-diisopropylaniline (1.06 g. 6.0 mmol), p-toluenesulfonic acid
monohydrate (200 mg), and toluene (25 mL) were placed in a 50-
mL flask equipped with Dean–Stark apparatus. After refluxing
overnight, the solvent was removed under vacuum, and the residue
was extracted with hexane (60 mL). The volume of the solution was
then concentrated to approximately 5 mL, and cooled to À208C to
give a white solid (0.95 g, 53% yield, m.p. 1038C); 1H NMR
(200 MHz, C6D6, 258C): d = 14.23 (br s, 1H; NH), 7.15–6.95 (m,
3H; imine-ph-H), 2.98 (septet, J = 6.8 Hz, 2H; iPr-CH), 2.19 (br s,
3H; CH3 in acetyl), 2.10 (br s, 3H; CH3 in acetyl), 1.75 (s, 3H; CH3),
1.01 (d, J = 6.6 Hz, 6H; iPr-CH3), 0.99 ppm (d, J = 6.6 Hz, 6H; iPr-
CH3); 13C NMR (100 MHz, CDCl3, 258C): d = 199.59 (br s, carbonyl),
166.21 (imine), 145.67, 132.77, 128.87, 123.98 (ph-C), 114.57 (ethyl-
ene), 31.67 (br s, CH3 in acetyl), 28.77 (iPr-CH), 24.66 (iPr-CH3), 22.75
(iPr-CH3), 18.06 ppm (CH3); HRMS (EI): m/z calcd for C19H27NO2,
301.2042; found, 301.2047; Elemental analysis calcd (%) for
C19H27NO2: C 75.71, H 9.03, N 4.65; found: C 75.60, H 8.87, N, 4.79.
K1: KH (64 mg, 1.6 mmol) was added to 3-[1-(2,6-diisopropyl-
phenylamino)ethylidene]pentane-2,4-dione (452 mg, 1.5 mmol) in
THF (5 g). After stirring for 3 h at room temperature, the reaction
mixture was filtered, and the solvent was removed under vacuum.
Trituration with pentane for 1 h gave the potassium salt (K1) as a
1
white solid (441 mg, in 87% yield). H NMR (200 MHz, C6D6/THF
(10/1), 258C): d = 7.13–6.98 (m, 3H; imine-ph-H), 2.22 (s, 6H; CH3 in
acetyl), 1.98 (s, 3H; CH3), 1.80 (septet, J = 7.2 Hz, 2H; iPr-CH), 1.24
(d, J = 6.8 Hz, 6H; iPr-CH3), 1.13 ppm (d, J = 6.8 Hz, 6H; iPr-CH3).
2: K1 (290 mg, 0.85 mmol) and [Ni(h1-CH2C6H5)Cl(PMe3)2]
(288 mg, 0.85 mmol) were stirred in THF (5 g) for 3 h at room
temperature. The reaction mixture was then filtered, the filtrate
collected, and the THF removed under vacuum. The residue was
extracted with pentane (25 g). The solution was concentrated to
approximately 4 mL and cooled to À358C to yield a yellow solid
1
(360 mg, 80% yield). H NMR (400 MHz, C6D6, 258C): d = 7.68 (d,
J = 7.2 Hz, 2H; benzyl-ph-H2,6), 7.25–7.11 (m, 6H; imine-ph-H and
benzyl-ph-H3,4,5), 3.06 (septet, J = 6.8 Hz, 2H; iPr-CH), 2.18 (s, 3H;
CH3 in acetyl), 2.07 (d, J = 6.8 Hz, 2H; benzyl-CH2), 1.92 (s, 3H; CH3
in acetyl), 1.62 (s, 3H; CH3), 1.16 (d, J = 6.8 Hz, 6H; iPr-CH3), 1.15 (d,
J = 6.8 Hz, 6H; iPr-CH3), 0.76 ppm (d, J = 10.0 Hz, 9H; PCH3);
13C NMR (100 MHz, C6D6, 258C): d = 184.96, 183.98 (carbonyl),
169.87 (imine), 149.97, 147.14, 136.89, 129.13, 128.82, 124.41, 123.97,
123.44 (ph-C), 118.63 (ethylene), 28.46 (iPr-CH), 27.88 (CH3 in
acetyl), 27.25 (CH3 in acetyl), 24.56 (CH3), 24.45 (iPr-CH3), 23.79 (iPr-
CH3), 12.92 (d, J = 28 Hz, PCH3), 12.28 ppm (d, J = 26 Hz, benzyl-
CH2); 31P NMR (162 MHz, C6D6, 258C): d = À6.79 ppm; Elemental
analysis calcd (%) for C29H42NO2PNi: C 66.18, H 8.04, N, 2.66; found:
C 66.11, H 7.40, N, 2.82.
3: Compound 2 (10.5 mg, 0.02 mmol) and one equivalent of
B(C6F5)3 (10.2 mg, 0.02 mmol) were mixed in C6D6 (0.9 mL). After
1 h, the solution was filtered, and 1H, 19F, 11B and 31P NMR spectra of
the filtrate were recorded. The spectra indicated the nearly quanti-
tative formation of complex 3. 1H NMR (400 MHz, C6D6, 258C): d =
7.40 (d, J = 8.0 Hz, 2H; benzyl-ph-H2,6), 7.18–7.05 (m, 6H; imine-ph-
H and benzyl-ph-H3,4,5), 2.46 (s, 3H; CH3 in acetyl), 2.12 (s, 3H; CH3),
1.47 (s, 3H; CH3-CO-B(C6F5)3), 0.94 (br d, J = 4.8 Hz, 6H; iPr-CH3),
0.46 ppm (d, J = 10.0 Hz, 9H; PCH3), iPr-CH, benzyl-CH2 and one of
iPr-CH3 not observed; 19F NMR (376 MHz, C6D6, 258C): d = À133.83,
À157.97, À163.91 ppm; 31P NMR (162 MHz, C6D6, 258C): d =
À7.92 ppm; 11B NMR (161 MHz, C6D6, 258C): d = À12.55 ppm.
Single crystals suitable for X-ray analysis formed after three days.
Angew. Chem. Int. Ed. 2005, 44, 1108 –1112
ꢀ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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