Organometallics
Article
residue was purified by flash chromatography first on basic alumina
using a gradient of 0 to 100% ethyl acetate in hexane, followed by a
silica column using a gradient of 0 to 10% methanol in dichloro-
methane. Yield: 1.44 g, 72%. 1H NMR (CDCl3): δ 8.57 (s, 1H), 8.07
40 °C for 2 days. The crude reaction mixture was then purified by air-
free flash chromatography using a gradient of 0 to 100% ethyl acetate
in dichloromethane. Material purified in this manner was pure by
NMR spectroscopy, but catalytic trials were conducted using samples
that were further purified by recrystallization: a solution in
dichloromethane was first layered with a small amount of toluene
and then an excess of pentane. Yield after recrystallization: 374 mg,
3
3
3
(d, JHH = 7.6 Hz, 1H), 7.85 (t, JHH = 7.6 Hz, 2H), 7.50 (d, JHH
=
7.6 Hz, 1H), 7.41−7.32 (m, 3H), 3.81 (s, 2H), 2.63 (q, 3JHH = 7.0 Hz,
3
4H), 1.09 (t, JHH = 7.0 Hz, 6H). 13C{1H} NMR: δ 161.70, 149.09,
1
144.79, 141.53, 139.25, 132.32, 124.15, 123.25, 120.85, 120.70,
112.88, 112.12, 59.16, 47.65, 12.21. HRMS (ESI+): calcd for
C17H21N4 (M + H), 281.1766; found, 281.1767.
56%. H NMR (CD2Cl2, assignments correspond to Figure S37): δ
3
8.03−7.90 (m, 2H, Hn,m), 7.86 (d, JHH = 8.1 Hz, 1H, Hl), 7.61 (t,
3
4
3JHH = 7.8 Hz, 1H, He), 7.49 (dd, JHH = 7.8 Hz, JHH = 1.3 Hz, 1H,
Synthesis of 4-iPr-Et. To a 150 mL glass medium-pressure vessel
in the glovebox were added 5-Et (2.15 g, 7.67 mmol), 2-
bromopropane (18.9 g, 154 mmol), a stir bar, and acetonitrile (10
mL). The vessel was capped, removed from the glovebox, and heated
at 120 °C overnight while stirring. The vessel was opened, and the
solvent was evaporated. The residue was purified by flash
chromatography on silica using a gradient of 0 to 40% methanol in
Hf), 7.39 (dd, JHH = 7.7 Hz, 4JHH = 1.3 Hz, 1H, Hd), 7.31 (t, 3JHH
=
3
8.1 Hz, 1H, Hk), 7.28−7.16 (m, 2H, Hj,o), 6.74 (d, 3JHH = 7.9 Hz, 1H,
Hi), 4.84 (d, 2JHH = 14.9 Hz, 1H, HpCl), 3.95 (d, 2JHH = 14.9 Hz, 1H,
2
3
HpH), 3.60 (dq, JHH = 14.1 Hz, JHH = 7.1 Hz, 1H, Hs), 3.34 (dq,
2JHH = 14.3 Hz, JHH = 7.2 Hz, 1H, Hs), 3.04 (hept, JHH = 6.8 Hz,
3
3
3
1H, Hg), 2.85 (m, 2H, Hq), 2.42−2.31 (m, 1H, Hb), 1.42 (d, JHH
=
6.7 Hz, 3H, Hh), 1.25 (d, 3JHH = 6.8 Hz, 3H, Hc), 1.18 (t, 3JHH = 7.0
Hz, 3H, Hr), 1.11 (t, 3JHH = 7.2 Hz, 3H, Ht), 1.01 (d, 3JHH = 6.9 Hz,
1
dichloromethane. Yield: 2.14 g, 57%. H NMR (CDCl3): δ 11.61 (s,
1H), 10.43 (br, 1H), 8.30 (d, 3JHH = 8.0 Hz, 1H), 8.19 (br, 3H), 7.93
3
3H, Hh), 0.95 (d, JHH = 6.9 Hz, 3H, Hc), −14.58 (s, 1H, Ha).
3
3
(d, JHH = 8.0 Hz, 1H), 7.74−7.65 (m, 2H), 5.21 (hept, JHH = 6.6
13C{1H} NMR: δ 215.70, 205.65, 160.10, 150.92, 148.64, 147.79,
138.95, 138.56, 132.91, 131.52, 130.67, 124.91, 123.72, 122.90,
116.92, 110.55, 110.25, 109.28, 64.35, 54.61, 49.97, 28.81, 28.63,
25.14, 24.81, 23.85, 23.69, 11.34, 8.93. The two meta carbons on the
13C signals at 124.91 ppm, which was verified by COSY experiments.
Anal. Calcd for C30H37N4ClORu: C, 59.44; H, 6.15; N, 9.24. Found:
C, 59.62; H, 6.17; N, 9.17.
3
Hz, 1H), 4.84 (br, 2H), 3.32 (br, 4H), 1.85 (d, JHH = 6.6 Hz, 6H),
1.39 (br t, 6H). 13C{1H} NMR: δ 151.93 (br), 145.96, 142.19,
140.92, 131.00, 129.26, 128.83, 127.93, 126.73, 116.90, 115.13,
114.10, 55.53, 52.97, 48.55, 22.28, 9.41. HRMS (ESI+): calcd for
C20H27N4 (M − H − 2Br), 323.2236; found, 323.2233.
Synthesis of Ru-dipp-iPr. In the glovebox, the trihydrochloride
salt 4-dipp-iPr (300 mg, 0.519 mmol), a stir bar, 3.5 Å molecular
sieves (1.2 g), Ag2O (601 mg, 2.59 mmol), and THF (10 mL) were
added to a vial, and the mixture was stirred at room temperature for
1.5 h in the dark. The mixture was filtered through a PTFE filter disk
into a vial containing RuHCl(CO)(PPh3)3 (494 mg, 0.519 mmol)
and AgCl (2.23 g, 15.6 mmol). The reaction mixture was stirred and
heated at 50 °C overnight. The crude reaction mixture was then
purified by air-free flash chromatography using a gradient of 0 to
100% ethyl acetate in dichloromethane. Material purified in this
manner was pure by NMR spectroscopy, but catalytic trials were
conducted using samples that were further purified by recrystalliza-
tion: a solution in dichloromethane was first layered with a small
amount of toluene and then an excess of pentane. Yield after
recrystallization: 156 mg, 47%. 1H NMR (CD2Cl2, assignments
Synthesis of Ru-dipp-Me. The synthesis, chromatographic
purification, and recrystallization of Ru-dipp-Me were performed in
an analogous fashion to Ru-dipp-Et, starting with 4-dipp-Me (200
mg, 0.383 mmol). Yield after recrystallization: 110 mg, 50%. 1H NMR
(CD2Cl2, assignments correspond to Figure S39): δ 7.93−7.80 (m,
2H, Hn,m), 7.75 (d, 3JHH = 8.1 Hz, 1H, Hl), 7.49 (t, 3JHH = 7.8 Hz, 1H,
He), 7.36 (dd, 3JHH = 7.8 Hz, 4JHH = 1.4 Hz, 1H, Hf), 7.27 (dd, 3JHH
=
4
3
4
7.8 Hz, JHH = 1.4 Hz, 1H, Hd), 7.20 (td, JHH = 7.9 Hz, JHH = 1.1
Hz, 1H, Hk), 7.10 (m, 2H, Hj,o), 6.62 (d, 3JHH = 7.7 Hz, 1H, Hi), 4.81
2
2
(d, JHH = 14.8 Hz, 1H, HpCl), 3.46 (d, JHH = 14.8 Hz, 1H, HpH),
2.97−2.84 (m, 4H, Hg,r), 2.66 (s, 3H, Hq), 2.23 (hept, 3JHH = 6.8 Hz,
1H, Hb), 1.29 (d, 3JHH = 6.7 Hz, 3H, Hh), 1.11 (d, 3JHH = 6.8 Hz, 3H,
Hc), 0.86 (d, 3JHH = 6.9 Hz, 3H, Hc), 0.84 (d, 3JHH = 6.9 Hz, 3H, Hc),
−14.58 (s, 1H, Ha). Residual CH2Cl2 was observed, integrating to 0.5
molar equiv. 13C{1H} NMR: δ 215.39, 204.88, 159.18, 150.67,
148.21, 147.32, 138.56, 138.13, 132.48, 131.17, 130.27, 124.50,
124.48, 123.37, 122.53, 116.47, 110.20, 109.86, 109.15, 68.86, 58.27,
51.43, 28.41, 28.21, 24.78, 24.38, 23.41, 23.35. Recrystallized samples
retained dichloromethane upon drying, as verified by 1H NMR
analysis. Anal. Calcd for C28H33ClN4ORu·0.5(CH2Cl2): C, 55.15; H,
5.52; N, 9.03. Found: C, 55.05; H, 5.72; N, 8.87.
correspond to Figure S35): δ 7.88−7.80 (m, 1H, Hn), 7.77 (d, 3JHH
8.2 Hz, 1H, Hm), 7.74 (d, 3JHH = 8.2 Hz, 1H, Hl), 7.49 (t, 3JHH = 7.8
=
3
4
Hz, 1H, He), 7.36 (dd, JHH = 7.8 Hz, JHH = 1.4 Hz, 1H, Hf), 7.27
(dd, 3JHH = 7.8 Hz, 4JHH = 1.4 Hz, 1H, Hd), 7.23−7.15 (m, 1H, Hk),
3
7.14−7.06 (m, 1H, Hj), 7.02 (d, JHH = 7.5 Hz, 1H, Ho), 6.64−6.58
(d, 3JHH = 7.7 Hz, 1H, Hi), 4.65 (d, 2JHH = 15.6 Hz, 1H, HpCl), 4.19−
4.11 (m, 1H, Hs), 4.03 (d, 2JHH = 15.6 Hz, 1H, HpH), 3.09 (hept, 3JHH
3
= 6.4 Hz, 1H, Hq), 2.91 (hept, JHH = 6.8 Hz, 1H, Hg), 2.29 (hept,
3JHH = 6.8 Hz, 1H, Hb), 1.41 (d, 3JHH = 6.9 Hz, 3H, Ht), 1.32 (d, 3JHH
= 6.7 Hz, 3H, Hh), 1.18 (d, 3JHH = 6.8 Hz, 3H, Ht), 1.16 (d, 3JHH = 6.8
Hz, 3H, Hc), 1.09 (d, 3JHH = 6.3 Hz, 3H, Hr), 1.01 (d, 3JHH = 6.5 Hz,
3H, Hr), 0.89 (d, 3JHH = 6.9 Hz, 3H, Hh), 0.84 (d, 3JHH = 6.9 Hz, 3H,
Hc), −14.31 (s, 1H, Ha). Residual CH2Cl2 was observed, integrating
to 0.5 molar equiv. 13C{1H} NMR: δ 215.12, 206.27, 163.22, 150.43,
148.75, 147.90, 139.21, 138.61, 132.86, 131.48, 130.74, 124.95,
123.70, 122.87, 115.60, 110.48, 110.22, 108.59, 63.29, 59.62, 57.38,
28.82, 28.66, 26.00, 25.15, 24.89, 23.95, 23.66, 23.44, 22.99, 18.44.
The two meta hydrogens on the dipp group (d and e in the
which was verified by HMQC experiments. Recrystallized samples
retained dichloromethane upon drying, as verified by 1H NMR
analysis. Anal. Calcd for C32H41N4ClORu·0.5(CH2Cl2): C, 57.68; H,
6.26; N, 8.28. Found: C, 57.78; H, 6.45; N, 8.32.
Synthesis of Ru-Mes-iPr. The synthesis, chromatographic
purification, and recrystallization of Ru-Mes-iPr were performed in
an analogous fashion to Ru-dipp-Et, starting with 4-Mes-iPr (300 mg,
0.560 mmol), except that the transmetalation step was carried out at
room temperature instead of 40 °C. Yield after recrystallization: 171
mg, 52%. 1H NMR (CD2Cl2, assignments correspond to Figure S41):
δ 8.00 (t, 3JHH = 7.8 Hz, 1H, Hl), 7.91−7.80 (m, 2H, Hk,j), 7.38−7.28
(t, 3JHH = 7.7 Hz, 1H, Hi), 7.27−7.20 (m, 2H, Hh,m), 7.18 (s, 1H, He),
7.11 (s, 1H, Hc), 6.80−6.69 (d, 3JHH3 = 7.2 Hz, 1H, Hg), 4.72 (d, 2JHH
= 15.6 Hz, 1H, HnCl), 4.31 (hept, JHH = 6.5 Hz, 1H, Hq), 4.17 (d,
2JHH = 15.6 Hz, 1H, HnH), 3.24 (hept, 3JHH = 6.5 Hz, 1H, Ho), 2.44 (s,
3
3H, Hd), 2.24 (s, 3H, Hf), 2.00 (s, 3H, Hb), 1.54 (d, JHH = 6.9 Hz,
3H, Hr), 1.30 (d, 3JHH = 6.9 Hz, 3H, Hr), 1.22 (d, 3JHH = 6.3 Hz, 3H,
3
Hp), 1.14 (d, JHH = 6.5 Hz, 3H, Hp), −14.31 (s, 1H, Ha). Residual
Synthesis of Ru-dipp-Et. In the glovebox, the trihydrochloride
salt 4-dipp-Et (600 mg, 1.09 mmol), a stir bar, 3.5 Å molecular sieves
(2.0 g), Ag2O (1.26 g, 5.45 mmol), and CH2Cl2 (20 mL) were added
to a vial, and the mixture was stirred at room temperature for 2 h in
the dark. The mixture was filtered through a PTFE filter disk into a
vial containing RuHCl(CO)(PPh3)3 (1.04 g, 1.09 mmol) and AgCl
(1.56 g, 10.9 mmol). The reaction mixture was stirred and heated at
CH2Cl2 was observed, integrating to 1.0 molar equiv. 13C{1H} NMR:
δ 215.70, 205.65, 160.10, 150.92, 148.64, 147.79, 138.95, 138.56,
132.91, 131.52, 130.67, 124.91, 123.72, 122.90, 116.92, 110.55,
110.25, 109.28, 64.35, 54.61, 49.97, 28.81, 28.63, 25.14, 24.81, 23.85,
23.69, 11.34, 8.93. Recrystallized samples retained dichloromethane
1
upon drying, as verified by H NMR analysis. The peak for CH2Cl2
H
Organometallics XXXX, XXX, XXX−XXX