S1
Supporting Information for the paper:
Formation and Cleavage of C—C and C—O Bonds of ortho-Methyl Substituted
Anisoles by Late Transition Metals.
Patricia Lara,a Margarita Paneque,a Manuel L. Poveda,a Verónica Salazar,b Laura L. Santos,a and
Ernesto Carmonaa
Instituto de Investigaciones Químicas-Departamento de Química Inorgánica, Consejo Superior de
Investigaciones Científicas, Universidad de Sevilla, Avda. Américo Vespucio nº 49, Isla de la
Cartuja, 41092 Sevilla, Spain, and Centro de Investigaciones Químicas, Universidad Autónoma del
Estado de Hidalgo, Pachuca, Hidalgo, México.
Contents:
Synthesis, and spectroscopic and analytical data for new compounds.
S2
Compounds 1a and 1b
HB
HC
[Ir]
H
HA
C2
O
C1
noe
C4
Me C3
R
R = H, 1a; Me, 1b
Synthesis:
The compound TpMe2Ir(C2H4)2 (0.30 g, 0.55 mmol) was dissolved in C6H6 (15 mL) and 2,6dimethylanisole (0.4 mL, 2.75 mmol) was added. The solution was stirred at 60 ºC for 12 h and the
solvent then evaporated under vacuum. NMR monitoring of the crude product revealed the
formation of 1a in almost quantitative yield (> 90%). 1a was purified by column chromatography
on silica gel, using a 5:1 mixture of hexane:CH2Cl2 as eluent. Yield: 49%. It can be crystallized
from pentane:Et2O mixtures (2:1) at -20 ºC.
The use of the corresponding anisole ArO13CH3, with ca. 45% 13C enrichment demonstrates
that the 13C label scrambles between the two olefinic sites of compounds 1a. The distribution
favours the terminal alkene carbon in ca. 70%.
Compound 1b was prepared similarly starting from 0.20 g (0.37 mmol) of TpMe2Ir(C2H4)2
and 0.28 mL (1.83 mmol) of 2,4,6-trimethylanisole in 8 mL of C6H6. The spectroscopic yield was
higher than 90% and the yield of isolated product, following chromatography as above, was 65%.
Use of the 13C enriched anisole ArO13CH3 (ca. 45%) leads to an almost even distribution of
the 13C label across the two olefinic sites of 1b (the terminal alkene carbon keeps 55% of the label).
Spectroscopic and analytical data:
1a:
IR (Nujol): ν(Ir-H) 2180 cm-1.
1
H NMR (CDCl3, 25 ºC): δ 7.11, 6.76, 6.45 (d, d, t, 1 H each, 3JHH ≈ 7.5 Hz, 3 CHar), 6.89 (dd, 1
H, 3JAC = 11.5, 3JAB = 8.2 Hz, HA), 5.95, 5.90, 5.68 (s, 1 H each, 3 CHpz), 4.26 (d, 1 H, HC), 3.28 (d,
1 H, HB), 2.08 (s, 3 H, C3-Me), 2.49, 2.43, 2.43, 2.40, 2.30, 2.00 (s, 3 H each, 6 Mepz), -17.47 (s, 1
H, IrH).
13
C{1H} NMR (CDCl3, 25 ºC): δ 171.7 (C1), 152.6, 151.0, 150.9, 144.1, 144.0, 143.7 (Cqpz), 130.3
(C2), 128.4, 123.6, 114.0 (CHar), 125.2 (C3), 108.2, 107.3, 106.8 (CHpz), 76.7 (1JCH = 164 Hz, CHA),
46.2 (1JCH = 161 Hz, CHBHC), 16.3 (C3-Me), 14.2, 13.7, 13.4, 12.9, 12.5 (1:1:1:1:2, Mepz).
Anal. Calc. for C24H32BIrN6O: C, 46.2; H, 5.1; N, 13.5. Found: C, 45.8; H, 5.1; N, 13.1.
1b:
IR (Nujol): ν(Ir-H) 2189 cm-1.
1
H NMR (CDCl3, 25 ºC): δ 6.89, 6.58 (s, s, 1 H each, 2 CHar), 6.83 (m, 1 H, HA), 5.91, 5.86, 5.64
(s, 1 H each, 3 CHpz), 4.23 (d, 1 H, 3JAC = 11.1 Hz, HC), 3.24 (d, 1 H, 3JAB = 8.2 Hz, HB), 2.45, 2.40,
2.39, 2.36, 2.29, 1.96 (s, 3 H each, 6 Mepz), 2.25 (s, 3 H, C4-Me), 2.02 (s, 3 H, C3-Me), -17.44 (s, 1
H, IrH).
13
C{1H} NMR (CDCl3, 25 ºC): δ 169.3 (C1), 152.6, 151.0, 150.8, 144.0, 143.9, 143.6 (Cqpz), 130.1
(C2), 129.3, 123.8 (CHar), 124.6 (C3), 122.8 (C4), 108.2, 107.2, 106.8 (CHpz), 76.6 (1JCH = 170 Hz,
CHA), 46.1 (1JCH = 161 Hz, CHBHC), 20.3 (C4-Me), 16.2 (C3-Me), 14.2, 13.7, 13.4, 12.8, 12.5
(1:1:1:1:2, Mepz).
Anal. Calc. for C25H34BIrN6O: C, 47.1; H, 5.3; N, 13.2. Found: C, 46.6; H, 5.2; N, 12.9.
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Compounds 3a and 4a:
[Ir]
C
Ph
H
Me
C1
[Ir]
H
C
H
O
C2
C1
Me
3a
H
O
C3
Me
4a
Synthesis:
The Ir(I) complex TpMe2Ir(C2H4)2 (0.30 g, 0.55 mmol) dissolved in C6H6 (3 mL) was reacted
with a slight excess of 2,6-dimethylanisole (0.090 mL, 0.66 mmol) at 50 ºC for 3 h. After removal
of the solvent in vacuo, 1H NMR spectroscopy revealed formation of 3a (ca. 26%) and 4a (ca. 5%)
together with 1a (ca. 5%). Two column chromatographic separations, the first with Et2O and the
second with pentane as eluents, followed by another two thin-layer chromatographic procedures,
both employing hexane as the eluent, allowed separation of the desired compounds (yellow solids;
3a, 30 mg, ca. 90% purity; 4a, 25 mg, ca. 96% purity) each slightly impurified by the other. During
the chromatography experiments partial conversion of 3a into 4a takes place.
Studies employing the 13C-enriched (ca. 45%) anisoles ArO13CH3 reveal that the label
appears exclusively at the carbene carbon of 3a and 4a (1JCH values of 154 (3a) and 159 Hz (4a) for
their Ir=CH- functionalities).
Spectroscopic and analytical data:
3a:
IR (Nujol): ν(Ir-H) 2141 cm-1.
1
H NMR (CDCl3, -10 ºC): δ 15.44 (s, 1 H, Ir=CH), 7.83, 6.99, 6.87, 6.67, 6.50 (d, t, t, t, d, 1 H
each, 3JHH ≈ 7.5 Hz, o, m, p, m’, o’-CH(Ir-Ph)), 7.02 (s, 3 H, CH(O-Ar)), 5.80, 5.76, 5.68 (s, 1 H
each, 3 CHpz), 2.48, 2.40, 2.38, 2.19, 1.57, 1.46 (s, 3 H each, 6 Mepz), 2.15 (s, 6 H, 2 Me(O-Ar)),
-14.89 (s, 1 H, IrH).
13
C{1H} NMR (CDCl3, -10 ºC): δ 259.2 (Ir=CH), 158.9 (C1), 151.7, 150.1, 148.6, 143.5, 143.4,
143.1 (Cqpz), 142.6, 139.8, 126.5, 126.0, 120.8 (o, o’, m, m’, p-CH(Ir-Ph)), 136.2 (Cq(Ir-Ph)), 129.3,
125.8 (2:1, CH(O-Ar)), 106.2, 106.0, 105.4 (CHpz), 16.8 (Mear), 15.8, 14.9, 14.5, 13.1, 12.9, 12.9
(Mepz).
4a:
IR (Nujol): ν(Ir-H) 2160 cm-1.
1
H NMR (CDCl3, - 10 ºC): δ 15.70 (s, 1 H, Ir=CH), 7.15, 7.03 (d, m, 1:2, 3JHH = 7.00 Hz, 3 CHar),
5.83, 5.83, 5.73 (s, 1 H each, 3 CHpz), 4.17, 2.48 (d, 1 H each, 2JHH = 13.1 Hz, IrCH2), 2.51, 2.43,
2.38, 2.36, 2.20, 1.93 (s, 3 H each, 6 Mepz), 2.31 (s, 3 H, Ar-Me), -17.04 (s, 1 H, IrH).
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C{1H} NMR (CDCl3, -10 ºC): δ 256.3 (1JCH = 159 Hz, Ir=CH), 157.5 (C1), 152.4, 150.0, 148.8,
144.6, 143.9, 143.3 (Cqpz), 140.9 (C2), 126.8 (C3), 126.4, 124.6, 124.6 (CHar), 106.9, 106.6, 105.4
(CHpz), 16.9, 15.0, 15.0, 14.1, 12.9, 12.8, 12.8 (Mepz + Ar-Me), -13.0 (1JCH = 127 Hz, Ir-CH2).
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OSiEt3
OSiEt3
C1
Me
C3
CH2CH3
C2
C1
Me
C3
CH2CH3
C2
C4
Me
Synthesis:
Compound 1a (0.1 g, 0.16 mmol) was dissolved in C6H12 (6 mL) and triethylsilane (0.8 mL,
0.16 mmol) was added. The solution was placed in a Fischer-Porter vessel and heated with stirring
under 4 atm of H2 (115 ºC for 21 h). After this period of time, the solution turned yellow and the
volatiles were removed under vacuum. The compound was purified by column chromatography on
silica gel, using pentane as eluent. Yield: 60%.
The use of the 13C-enriched compound 1a leads to the 13C-enriched silyl ether. The
distribution of the 13C label is identical to that in 1a.
Spectroscopic and analytical data:
1
H NMR (CDCl3, 25 ºC): δ 7.00 (m, 2 H, 2 CHar), 6.85 (t, 1 H, 3JHH = 7.5 Hz), 2.63 (q, 2 H, 3JHH =
7.5 Hz, C2CH2CH3), 2.25 (s, 3 H, C3Me), 1.22 (t, 3 H, 3JHH = 7.5 Hz, C2CH2CH3), 1.00 (t, 9 H, 3JHH
= 8.0 Hz, Si(CH2CH3)3), 0.79 (q, 6 H, 3JHH = 8.0 Hz, Si(CH2CH3)3).
13
C{1H} NMR (CDCl3, 25 ºC): δ 152.4 (C1), 134.3 (C2), 128.5, 126.5, 121.3 (CHar), 128.6 (C3),
23.8 (1JCH = 126 Hz, C2CH2CH3), 17.8 (1JCH = 126 Hz, C3Me), 14.3 (1JCH = 126 Hz, C2CH2CH3),
6.9 (1JCH = 125 Hz, Si(CH2CH3)3), 5.8 (1JCH = 117 Hz, Si(CH2CH3)3).
HRMS m/z calcd. for C15H26OSi (found): 250.175294 (250.175488).
The related silyl ether derived from 2,4,6-trimethylanisole was prepared similarly.
1
H NMR (CDCl3, 25 ºC): δ 6.76, 6.74 (s, 1 H each, 2 CHar), 2.54 (q, 2 H, 3JHH = 7.5 Hz,
C2CH2CH3), 2.21, 2.17 (s, 3 H each, C3Me and C4Me), 1.16 (t, 3 H, 3JHH = 7.5 Hz, C2CH2CH3),
0.96 (t, 9 H, 3JHH = 8.0 Hz, Si(CH2CH3)3), 0.73 (q, 6 H, 3JHH = 8.0 Hz, Si(CH2CH3)3).
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C{1H} NMR (CDCl3, 25 ºC): δ 150.0 (C1), 133.9 (C2), 129.1, 127.1 ( CHar), 130.3, 127.9 (C3 and
C4), 23.7 (C2CH2CH3), 20.6, 17.7 (1JCH = 126 Hz, C3Me and C4Me), 14.3 (1JCH = 126 Hz,
C2CH2CH3), 6.8 (1JCH = 126 Hz, Si(CH2CH3)3), 5.8 (1JCH = 118 Hz, Si(CH2CH3)3).
HRMS m/z calcd. for C16H28OSi (found): 264.190944 (264.190159).
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Compounds 2a and 2b:
OH
C1
Me
C3
CH2CH3
C2
C4
R
R = H, 2a; Me, 2b
Synthesis:
The compound triethyl(2-ethyl-6-methylphenoxy)silane (0.06 g, 0.24 mmol) was dissolved
in THF (3 mL) and tetrabutylammonium fluoride (1M in THF; 0.26 mL, 0.260 mmol) was added.
The solution was stirred for 2 h at room temperature. After this period of time, a saturated solution
of NH4Cl (3 mL) was added and compound 2a was extracted with ethyl acetate (3 x 3 mL). The
combined organic solvents were dried over Na2SO4 and evaporated. Quantitative conversion into
the product 2a was ascertained by 1H NMR and the pure product characterized by comparison with
literature data.1
2a:
H NMR (CDCl3, 25 ºC): δ 6.95, 6.94, 6.74 (d, d, t, 1 H each, 3JHH = 7.5 Hz, 3 CHar), 5.00 (s, 1 H,
-OH), 2.62 (q, 2 H, 3JHH = 7.5 Hz, -CH2CH3), 2.24 (s, 3 H, Mear), 1.21 (t, 3 H, 3JHH = 7.5 Hz,
-CH2CH3).
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C{1H} NMR (CDCl3, 25 ºC): δ 151.9, 129.4, 123.2 (Cqar), 128.4, 126.8, 120.2 (1JCH = 155 Hz,
CHar), 23.1 (1JCH = 126 Hz, -CH2CH3), 16.1 (Mear), 14.0 (1JCH = 126 Hz, -CH2CH3).
1
The phenol 2b was produced similarly.2
2b:
1
H NMR (CDCl3, 25 ºC): δ 6.75 (s, 2 H, 2 CHar), 4.87 (s, 1 H, -OH), 2.57 (q, 2 H, 3JHH = 7.5 Hz,
C2CH2CH3), 2.20 (s, 6 H, 2 Mear), 1.19 (t, 3 H, 3JHH = 7.5 Hz, -CH2CH3).
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C{1H} NMR (CDCl3, 25 ºC): δ 149.6, 129.3, 129.2, 123.1 (Cqar), 129.0, 127.3 (1JCH = 155 Hz,
CHar), 23.2 (1JCH = 128 Hz, -CH2CH3), 20.5, 16.0 (Mear), 14.2 (-CH2CH3).
1
2
Gassman, P. G.; Amick, D. R. J. Am. Chem. Soc. 1978, 100, 7611.
v.Auwers; Bundesmann; Wieners; JLACBF; Justus Liebigs Ann. Chem. 1926, 447, 180.