Pd-Catalysed Decarboxylative Suzuki Reactions and Orthogonal Cu-based O-Arylation of Aromatic ...

99 Pages·2010·1.24 MB·English

Supplementary Material (ESI) for Chemical Communications
This journal is (c) The Royal Society of Chemistry 2011

Pd-Catalysed Decarboxylative Suzuki Reactions and Orthogonal Cu-based
O-Arylation of Aromatic Carboxylic Acids

Jian-Jun Dai, Jing-Hui Liu, Dong-Fen Luo and Lei Liu*
Department of Chemistry, Tsinghua University, Beijing 100084, China
Email: [email protected]

Supporting Information

Table of Contents

1. General Information……………………………………………………………S2
a. Materials
b. Methods
2. Experimental Section………………………………………………………….S2-7
a. Synthesis of the arylboron reagents
b. Preparation of the catalysts
c. Optimization of the reaction conditions
d. General procedures for the Pd-catalysed decarboxylative Suzuki cross-coupling
e. General procedures for the Cu-catalysed O-arylation of aromatic carboxylic acids
3. Characterization of the Products…………………………………………….S8-23
NMR spectra data of compounds
4. Copies of 1H-NMR and 13C-NMR Spectra…………………………………S24-94

S1
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1. General Information………………………………………......................................
a. Materials
All reactions were carried out in oven-dried vials. The solvents, i.e. DMSO, NMP, DMF, DMAc,
diglyme, were bought from Sigma-Aldrich (Sealed under argon) without further purification. All
benzoic acids were purchased from Alfa Aesar, TCI or Sigma-Aldrich. All aryl boronic acids were
purchased from Alfa Aesar, J&K or Sigma-Aldrich and used directly. All Ag and Cu salts were
bought from Sigma-Aldrich, Strem, or Alfa Aesar. All the other reagents and solvents were bought
from Sinopharm Chemical Reagent Co. Ltd or Alfa Aesar and were purified when necessary.

b. Methods
1H-NMR, 13C-NMR, 19F-NMR spectra were recorded on a Bruker Advance 400 spectrometer at
ambient temperature in CDCl unless otherwise noted. Data for 1H-NMR are reported as follows:
3
chemical shift (δ ppm), multiplicity, integration, and coupling constant (Hz). Data for 13C-NMR are
reported in terms of chemical shift (δ ppm). Data for 19F-NMR are reported as follows: chemical
shift (δ ppm), multiplicity, integration, and coupling constant (Hz). Gas chromatographic (GC)
analysis was acquired on a Shimadzu GC-2014 Series GC System equipped with a flame-ionization
detector. GC-MS analysis was performed on Thermo Scientific AS 3000 Series GC-MS System.

High-resolution mass spectra (HRMS) were recorded on a BRUKER VPEXII spectrometer with EI
mode. Elementary analysis was carried out on Elementar Vario EL IIIelemental analyzer. Organic

solutions were concentrated under reduced pressure on a Buchi rotary evaporator. Flash column
chromatographic purification of products was accomplished using forced-flow chromatography on
Silica Gel (200-300 mesh).
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2. Experimental Section……………………………………………………………….
a. Synthesis of the arylboron reagents.
Table S1
Sylvain Darses; Guillaume Michaud; Jean-Pierre Geneˆt
Ar BF3K
Eur. J. Org. Chem., 1999,1875.
Franklin A.Davis; Ignatius J.Turchi; Bruce E.Maryanoff;
Robert O.Hutchins J. Org. Chem., 1972, 37, 1583.

H. G. Kuivila; A. H. Keough, E. J. Soboczenski J. Org.
Chem., 1954, 19, 780.

Eric P. Gillis; Martin D. Burke J. Am. Chem. Soc., 2007,
129, 6716.

Robert L. Letsinger; Ivan Skoog J. Am. Chem. Soc., 1955,
77, 2491.

b. Preparation of the catalyst:

Preparation of palladium (II) trifluoroacetate:

A 50 ml oven-dried flask was charged with Pd(OAc) (1.0 g, 4.46 mmol). 25 ml trifluoroacetatic acid
2
was added. The mixture was stirred and heated to reflux (at 90 °C) in an oil bath. A gray-brown solid
was formed as the mixture was heated. The solid was isolated by filtration and washed with
trifluoroacetic acid (ca. 10 ml). The residue was dried under vacuum at 40°C for 3 h offering a
brownish powder.
Reference: Daniel P. Bancroft; F. Albert Cotton; Mark Verbruggen Acta Cryst. 1989, C45, 1289.

Preparation of bis(acetonitrile) palladium (II) p-toluenesulfonate:

To a clear dark orange solution of Pd(OAc) (0.33 g, 1.47 mmol) in acetonitrile (30 ml) a solution of
2
p-toluenesulfonic acid (1.5 g, 7.9 mmol) in acetonitrile (40 ml) was added dropwise with stirring.
The color gradually changed to pale yellow. Subsequently diethyl ether (50 ml) was added, and this
resulted in precipitation of fine pale yellow microcrystals. The suspension was set aside over night
and the supematent liquid was decanted. The crystals were washed with diethyl ether, dried under a
slight vacuum, and shown to be Pd(MeCN) (OTs) .
2 2
Reference: E. Drent; J. A. M. van Broekhoven; M. J. Doyle J. Organomet. Chem., 1991, 417, 235.

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Preparation of bis(acetonitrile)dichloropalladium(II):

A suspension of PdCl (1.00 g, 5.65 mmol) was heated to reflux in CH CN (50 ml) with vigorous
2 3
stirring for 10 h under N . Hot filtration of the resultant wine-red coloured solution through a ceolite
2
pad into stirred petroleum spirit (40–60 oC) at room temperature afforded a yellow-orange solid.
Recrystallisation from CH CN (100 ml), DCM (150 ml) and hexane (50 ml) gave (CH CN) PdCl as
3 3 2 2
a bright yellow powdery solid.
Reference: Mathews, Christopher J.; Smith, Paul J.; Welton, Tom J. Mol. Catal. A Chem., 2003, 206,
77.

c. Optimization of the reaction conditions:

General Procedure:

A 10ml oven-dried vial was charged with Pd(TFA) (0.04 mmol), Ag CO (0.6 mmol),
2 2 3
2,4,6-trimethoxybenzoic acid (0.2 mmol), benzeneboronic acid (0.4 mmol). DMSO (1.0 ml) was
added by syringe at room temperature. The vial was then sealed and the mixture was allowed to stir
at the appointed temperature (120 ± 5 °C) for 2 h. Upon completion of the reaction, the mixture was
cooled to room temperature and diluted with ethyl acetate, and analyzed by gas chromatography.

STable2
Decarboxylative Suzuki coupling between 2,4,6-trimethoxybenzoic acidand organoboron reagents[a].

Table S2

PhBM PhB(OH) PhBF K
2 3

Yield[%][b] 96 95 86 60 6 10

[a] Condition for this transformation: 0.2 mmol of, 0.4 mmol of benzeneboronic acid, 20% mol of
catalyst, 3.0 equiv.Ag CO , 1ml DMSO, 120°C, 2 h. GC yields were determined with the use of
2 3
benzophenone as an internal standard. [b]Yields were based on 2,4,5-trimethoxybenzoic acid.
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STable 3
Various conditions towards the decarboxylative cross-coupling between 2,4,6-trimethoxybenzoic
acidand benzeneboronic acid[a]

Table S3
Entry Pd Source Ag Source Solvent Yield [%][b]
1 Pd(TFA) Ag CO DMF 10
2 2 3
2 Pd(TFA) Ag CO NMP trace
2 2 3
3 Pd(TFA) Ag CO DMSO:DMF=1:9 69
2 2 3
4 Pd(TFA) Ag CO DMSO:NMP=1:9 80
2 2 3
5 Pd(OAc) Ag CO DMSO 51
2 2 3
6 PdCl Ag CO DMSO 53
2 2 3
7 Pd(CH CN) Cl Ag CO DMSO 54
3 2 2 2 3
8 Pd(TFA) Ag CO DMSO 96
2 2 3
9[c] Pd(TFA) Ag CO DMSO 95
2 2 3
10[d] Pd(TFA) Ag CO DMSO 61
2 2 3
11[e] Pd(TFA) Ag CO DMSO 35
2 2 3
12 / Ag CO DMSO 0
2 3
13 Pd(TFA) / DMSO trace
2
14 Pd(CH CN) (BF4) Ag CO DMSO 74
3 4 2 2 3
15 Pd(CH CN) (OTS) Ag CO DMSO 61
3 2 2 2 3
16 Pd(TFA) Ag PO DMSO 36
2 3 4
17 Pd(TFA) Ag O DMSO 79
2 2
18 Pd(TFA) AgOAc DMSO 22
2
19 Pd(TFA) AgTFA DMSO 7
2
20 Pd(TFA) AgF DMSO 53
2 2
21 Pd(TFA) AgOTs DMSO 5
2
22 Pd(TFA) AgOMs DMSO 4
2
23 Pd(TFA) Ag SO DMSO 6
2 2 4
24 Pd(TFA) AgBF DMSO 26
2 4
25 Pd(TFA) AgNO DMSO 16
2 3
[a]Condition for this transformation: 0.2 mmol of 2,4,6-trimethoxybenzoic acid, 0.4 mmol of
benzeneboronic acid, 20% mol of catalyst, 3.0 equiv. [Ag], 1ml of solvent, 120°C, 30 min. GC
yields were determined with the use of benzophenone as an internal standard. [b]Yields were
based on 2,4,5-trimethoxybenzoic acid. [c] 10min. [d] 10 mol% Pd(TFA) [e] 5 mol%
2.
Pd(TFA) .
2

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d. General Procedure for Pd-catalysed decarboxylative Suzuki cross-coupling:

General procedure :

Palladium(II) trifluoroacetate (0.04 mmol), Ag CO (0.6 mmol), benzoic acid (0.2 mmol) and the
2 3
aryl boronic reagent (0.4 mmol) were placed in an oven-dried 10 ml vial. Then DMSO (1 ml) was
added with a syringe. The vial was sealed and stirred at 120±5°C for the appointed time. Upon
completion of the reaction, the mixture was cooled to room temperature and diluted with diethyl
ether (30 ml). It was then filtered through a short silica column to remove the deposition. The
organic layers were washed with water (50 ml×2), and then with brine, dried over MgSO , and
4
filtered. The solvents were removed. Purification of the residue by column chromatography (silica
gel, ethyl acetate/petroleum ether) yielded the desired product.

STable 4
Various conditions towards the Cu-catalysed cross-coupling between 2,4,6-trimethoxybenzoic acid

and benzeneboronic acid[a]
OMe OMe
20mol%[Cu] O
MeO COOH + PhB(OH)2 MeO
base,Solvent O
1a OMe 120oC,2h 6a OMe

Table S4
Entry Cu Source Base Solvent Yield [%][b]
1[c] CuF Ag CO DMSO 87
2 2 3
2 CuF Ag CO DMSO 35
2 2 3
3 Cu(OAc) Ag CO DMSO 78
2 2 3
4 CuCl Ag CO DMSO 82
2 2 3
5 CuI Ag CO DMSO 85
2 3
6 Cu(OTf) Ag CO DMSO 93
2 2 3
7 / Ag CO DMSO 0
2 3
8 Cu(OTf) / DMSO trace
2
9 Cu(OTf) AgOAc DMSO 16
2
10 Cu(OTf) AgOTs DMSO trace
2
11 Cu(OTf) Ag O DMSO 77
2 2
12 Cu(OTf) Ag CO DMF 74
2 2 3
13 Cu(OTf) Ag CO NMP 61
2 2 3
14 Cu(OTf) Ag CO Toluene 10
2 2 3
15 Cu(OTf) Ag CO Diglyme 0
2 2 3
16 Cu(OTf) Ag CO DMAc 75
2 2 3
17[d] Cu(OTf) K CO DMSO trace
2 2 3
18[d] Cu(OTf) Na CO DMSO trace
2 2 3
19[d] Cu(OTf) Prydine DMSO 36
2
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[a] Condition for this transformation: 0.2 mmol of 2,4,6-trimethoxybenzoic acid, 0.4 mmol of
benzeneboronic acid, 20% mol of catalyst, 2.0 equiv. base, 1ml of solvent, 120°C, 2 h. GC
yields were determined with the use of benzophenone as an internal standard. [b] Yields
were based on 2,4,5-trimethoxybenzoic acid. [c] 1.0 eq. CuF2. [d] 200 mg 4Å MS,1 atm O
2
as the oxidant.

e. General procedure for the Cu-catalysed O-arylation of aromatic carboxylic acids
General procedure :
Copper(II) trifluoromethanesulfonate (0.04 mmol), Ag CO (0.4 mmol), benzoic acid (0.2 mmol)
2 3
and the aryl boronic acid (0.4 mmol) were placed in an oven-dried 10 ml vial. Then DMSO (1 ml)
was added with a syringe. The vial was sealed and stirred at 120±5°C for the appointed time. Upon
completion of the reaction, the mixture was cooled to room temperature and diluted with diethyl
ether (30 ml). It was then filtered through a short silica column to remove the deposition. The
organic layers were washed with water (50 ml×2), and then with brine, dried over MgSO , and
4
filtered. The solvents were removed. Purification of the residue by column chromatography (silica
gel, ethyl acetate/petroleum ether) yielded the desired product.
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3. Characterization of the Products………………………………………………….

2,4,6-trimethoxybiphenyl (3a). Spectral data corresponds to that previously reported. Colorless
solid (45 mg, 92% yield). 1H-NMR (400 MHz, CDCl ) δ 3.71 (s, 6H), 3.86 (s, 3H), 6.23 (s, 2H), 7.33
3
(m, 5H). 13C-NMR (100 MHz, CDCl ) δ 55.39, 55.90, 90.99, 112.62, 126.49, 127.63, 131.22, 134.14,
3
158.39, 160.53.
Reference: Ikuya Ban; Tomoko Sudo; Tadashi Taniguchi; Kenichiro Itami Org. Lett. 2008, 10,
3607.
OMe
MeO OMe
3b
2,4,6-trimethoxy-4'-methylbiphenyl (3b). Spectral data corresponds to that previously reported.
Colorless solid (45 mg, 87% yield). 1H-NMR (400 MHz, CDCl ) δ 2.36 (s, 3H), 3.69 (s, 6H), 3.84 (s,
3
3H), 6.22 (s, 2H), 7.17-7.23 (m, 4H). 13C-NMR (100 MHz, CDCl ) δ 21.39, 55.41, 55.92, 91.00,
3
112.54, 128.54, 128.91, 131.07, 136.04, 158.49, 160.45.
Reference: Ikuya Ban; Tomoko Sudo; Tadashi Taniguchi; Kenichiro Itami Org. Lett. 2008, 10,
3607.

4'-bromo-2,4,6-trimethoxybiphenyl (3c). Spectral data corresponds to that previously reported.
Colorless solid (61 mg, 95% yield). 1H-NMR (400 MHz, CDCl ) δ 3.72 (s, 6H), 3.86 (s, 3H), 6.22 (s,
3
2H), 7.20 (d, 2H, J=8.0 Hz), 7.48 (d, 2H, J=8.0 Hz). 13C-NMR (100 MHz, CDCl ): δ 55.40, 55.85,
3
90.94, 111.21, 120.50, 130.79, 133.00, 133.06, 158.22, 160.82.
Reference: Ikuya Ban; Tomoko Sudo; Tadashi Taniguchi; Kenichiro Itami Org. Lett. 2008, 10,
3607.

4'-phenyl-2,4,6-trimethoxybiphenyl (3d). Colorless solid (64 mg, 94% yield). 1H-NMR (400 MHz,
CDCl ) δ 3.74 (s, 6H), 3.87 (s, 3H), 6.25 (s, 2H), 7.32 (m, 1H), 7.43 (m, 4H), 7.62 (m, 4H).
3
13C-NMR (100 MHz, CDCl ): δ 55.42, 55.95, 91.02, 112.07, 126.45, 126.98, 127.18, 128.67, 131.64,
3
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133.17, 139.18, 141.39, 158.46, 160.63. HRMS (EI) calcd for C H O : 320.1412; found: 320.1407.
21 20 3

2,4,6-trimethoxy-4'-(trifluoromethyl)biphenyl (3e). Colorless solid (56 mg, 89% yield). 1H-NMR
(400 MHz, CDCl ) δ 3.71 (s, 6H), 3.85 (s, 3H), 6.23 (s, 2H), 7.44 (d, 2H, J=8.0 Hz), 7.60 (d, 2H,
3
J=8.0 Hz). 13C-NMR(100 MHz, CDCl ) δ 55.40, 55.83, 90.96, 111.05, 124.47(q, J=3.5 Hz),
3
124.57(q, J=271 Hz, CF ), 128.32(q, J=32.1 Hz), 131.67, 138.20(d, J=1.4 Hz), 158.30, 161.17.
3
19F-NMR(377 MHz, CDCl ): δ -62.29 (s). HRMS (EI) m/z calcd for C H F O : 312.0973; found:
3 16 15 3 3
312.0914.

2,4,4',6-tetramethoxybiphenyl (3f). Spectral data corresponds to that previously reported. Colorless
solid (40 mg, 72% yield). 1H-NMR (400 MHz, CDCl ) δ 3.72 (s, 6H), 3.83 (s, 3H), 3.86 (s, 3H), 6.22
3
(S, 2H), 6.93 (d, 2H, J=8.8Hz), 7.26 (d, 2H, J=8.8Hz). 13C-NMR(100 MHz, CDCl ) δ 55.13, 55.39,
3
55.91, 90.89, 112.05, 113.25, 126.14, 132.20, 158.12, 158.43, 160.28.
Reference: Jean-Michel Becht; Cedric Catala; Claude Le Drian; Alain Wagner Org. Lett. 2007, 9,
1781.
O
OMe
MeO OMe
3g

1-(2',4',6'-trimethoxybiphenyl-4-yl)ethanone (3g). Colorless solid (48 mg, 84% yield). 1H-NMR
(400 MHz, CDCl ) δ 2.61 (s, 3H), 3.72 (s, 6H), 3.87 (s, 3H), 6.23 (s, 2H), 7.44 (m, 2H, J=8.4 Hz),
3
7.97 (m, 2H, J=8.4Hz). 13C-NMR(100 MHz, CDCl ) δ 26.57, 55.42, 55.87, 90.95, 111.32, 127.69,
3
131.56, 135.14, 139.78, 158.27, 161.14, 197.98. HRMS (EI) m/z calcd for C H O : 286.1205;
17 18 4
found: 286.1198.

2-(2,4,6-trimethoxyphenyl)naphthalene (3h). Spectral data corresponds to that previously reported.
Colorless solid (54 mg, 92% yield). 1H-NMR (400 MHz, CDCl ) δ 3.78 (s, 6H), 3.94 (s, 3H), 6.34 (s,
3
2H), 7.53 (m, 3H), 7.90 (m, 4H). 13C-NMR(100 MHz, CDCl ) δ 55.44, 55.96, 91.15, 112.57, 125.48,
3
125.53, 126.86, 127.68, 128.10, 128.90, 129.84, 129.99, 130.96, 131.80, 132.40, 133.43, 158.62,
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160.74. HRMS (EI) m/z calcd for C H O : 294.1256; found: 294.1263.
17 18 4
Reference: Ikuya Ban; Tomoko Sudo; Tadashi Taniguchi; Kenichiro Itami Org. Lett. 2008, 10,
3607.

2',4',6'-trimethoxybiphenyl-4-carbonitrile (3i). Colorless solid (39 mg, 72% yield). 1H-NMR (400
MHz, CDCl ) δ 3.72 (s, 6H), 3.86 (s, 3H), 6.22 (S, 2H), 7.44 (m, 2H, J=8.8 Hz), 7.63 (m, 2H, J=8.8
3
Hz). 13C-NMR(100 MHz, CDCl ) δ 55.45, 55.82, 90.93, 109.82, 110.50, 119.49, 131.29, 132.20,
3
139.61, 158.15, 161.47. HRMS (EI) m/z calcd for C H NO : 269.1052; found: 269.1021.
16 15 3

Ethyl 2',4',6'-trimethoxybiphenyl-4-carboxylate (3j). Colorless solid (51 mg, 81% yield).
1H-NMR (400 MHz, CDCl ) δ 1.39 (t, 3H, J=7.2 Hz), 3.72 (s, 6H), 3.86 (s, 3H), 4.38 (q, 2H, J=7.2
3
Hz), 6.23 (S, 2H), 7.40 (d, 2H, J=8.4 Hz), 8.05 (d, 2H, J=8.4 Hz). 13C-NMR(100 MHz, CDCl ) δ
3
14.40, 55.40, 55.85, 60.68, 90.96, 111.55, 128.40, 128.83, 131.31, 139.34, 158.28, 161.03, 166.80.
HRMS (EI) m/z calcd for C H O : 316.1311; found: 316.1292.
18 20 5

3'-chloro-2,4,6-trimethoxybiphenyl (3k). Spectral data corresponds to that previously reported.
Colorless solid (47 mg, 85% yield). 1H-NMR (400 MHz, CDCl ): δ 3.72 (s, 6H), 3.86 (s, 3H), 6.21 (s,
3
2H), 7.26 (m, 4H). 13C-NMR(100 MHz, CDCl ) δ 55.41, 55.87, 90.81, 111.04, 126.58, 128.78,
3
129.53, 131.35, 133.34, 136.0, 158.27, 160.92.
Reference: Ikuya Ban; Tomoko Sudo; Tadashi Taniguchi; Kenichiro Itami Org. Lett. 2008, 10,
3607.

3'-fluoro-2,4,6-trimethoxybiphenyl (3l). Spectral data corresponds to that previously reported.
Colorless solid (51 mg, 97% yield). 1H-NMR (400 MHz, CDCl ) δ 3.73 (s, 6H), 3.86 (s, 3H), 6.22 (s,
3
2H), 6.97 (t, 1H, J=8.4Hz), 7.05 (d, 1H, J=10.0Hz), 7.10 (d, 1H, J=7.6Hz), 7.32 (m, 1H).
13C-NMR(100 MHz, CDCl ) δ 55.41, 55.87, 90.82, 111.19, 113.33 (d, J=21 Hz), 118.22 (d, J=21
3
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