Palladium-phosphinous acid catalyzed cross-coupling of aryl halides using a hypervalent phenylsilane in water

Article abstract of DOI:10.1055/s-2005-870013

A palladium-phosphinous acid catalyzed NaOH-promoted cross-coupling methodology that affords biaryls from tetrabutylammonium triphenyldifluorosilicate and aryl halides in good to high yields has been developed. The coupling proceeds in aqueous 0.5 M NaOH solution in the absence of organic co-solvents and does not require inert atmosphere, which greatly facilitates operation and catalyst handling. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2005-870013

PAPER
2287
Palladium–Phosphinous Acid Catalyzed Cross-Coupling of Aryl Halides
Using a Hypervalent Phenylsilane in Water
P
alladium–Phosp
a
hinous
A
ci
c
d
Catalyzed
h
C
ross-Coup
e
ling of
A
ry
l
l
H
alides Lerebours, Christian Wolf*
Department of Chemistry, Georgetown University, Washington, DC 20057, USA
Fax +1(202)6876209; E-mail: cw27@georgetown.edu
Received 28 February 2005
To date, few examples of Suzuki,12 Buchwald–Hartwig,13
Sonogashira,14 Stille,15 and Heck reactions16 that do not
require anhydrous reaction conditions have been report-
ed.17 The use of resin-supported palladium catalysts and
Abstract: A palladium–phosphinous acid catalyzed NaOH-pro-
moted cross-coupling methodology that affords biaryls from tet-
rabutylammonium triphenyldifluorosilicate and aryl halides in good
to high yields has been developed. The coupling proceeds in aque-
ous 0.5 M NaOH solution in the absence of organic co-solvents and the introduction of palladium acetate to microwave-assist-
does not require inert atmosphere, which greatly facilitates opera-
ed Suzuki coupling have provided new venues to high-
throughput C–C bond formation in aqueous solution.18 As
tion and catalyst handling.
Key words: biaryls, cross-coupling, silicon, palladium, catalysis
a consequence of the increasing availability and remark-
able reactivity in conjugate additions to a,b-unsaturated
carbonyl compounds or Hiyama-like coupling reactions,19
organosiloxanes have recently been utilized in aqueous
transition-metal-catalyzed coupling reactions using 10–
40% water in dioxane.20
Transition-metal-catalyzed carbon–carbon bond forming
reactions such as Suzuki,1 Negishi,2 Kumada,3 Heck,4 and
Stille5 couplings utilizing readily available aryl halides
are among the most important fundamental transforma-
tions in synthetic chemistry. Aryl bromides and iodides
are known to be better coupling partners than aryl chlo-
rides because of their weaker carbon–halide bond and
therefore inherently higher reactivity toward oxidative ad-
dition to Pd(0) species.6 However, there has been a grow-
ing interest in developing highly active transition metal
catalysts that allows one to employ aryl chlorides in cross-
coupling reactions.7
Recently, we and others have developed palladium–phos-
phinous acid catalyzed C–C, C–N and C–S bond forma-
tions including Stille and Heck coupling reactions.21
Herein we wish to present the use of palladium–phosphi-
nous acid complexes [(t-Bu)2P(OH)]2PdCl2 (POPd), {[(t-
Bu)2P(OH)(t-Bu)2PO)}PdCl]2
(POPd1)
and
[(t-
Bu)2P(OH)PdCl2]2 (POPd2) in cross-coupling reactions
of aryl halides and tetrabutylammonium triphenyldifluo-
rosilicate, TBAT, in water and under aerobic conditions
(Figure 1).
Siloxanes are easy to handle, environmentally benign and
they provide a non-toxic alternative for coupling reactions
with organostannanes.8 Fu and co-workers reported fluo-
ride-promoted Hiyama cross-couplings of a phenylsilox-
ane with aryl bromides and iodides.9 DeShong employed
various siloxanes such as phenyltrimethoxysilanes and
TBAT in cross-coupling reactions of aryl halides and tri-
flates and obtained good to high yields.10 Lee and co-
workers reported efficient cross-couplings of aryl chlo-
rides and bromides with phenyl- and vinyltrimethoxysi-
lane mediated by palladium acetate in the presence of an
imidazolium chloride.11
Initially, we screened the reaction conditions of the Pd(0)-
catalyzed coupling of 3-bromopyridine (1), and TBAT in
pure water under air (Scheme 1). Comparison of POPd,
POPd1 and POPd2 showed that the latter gave superior re-
sults, providing 3-phenylpyridine (17) in 61% yield
(Table 1, entries 1–3). We found that the reaction requires
at least two equivalents of TBAT and observed that yields
of 17 increased to 70–75% in the presence of TBAF (en-
tries 4–8). Further screening revealed that TBAF can be
replaced by tetraoctylammonium fluoride (TOAF), with-
out compromising yields, whereas CsF and tetraethylam-
monium fluoride (TEAF), provided 17 in small amounts.
t-Bu
O
t-Bu
OH
Pd
t-Bu
t-Bu
Cl
Pd
t-Bu
t-Bu
t-Bu
t-Bu
t-Bu
OH
t-Bu
OH
P
Cl
P
O
P
P
P
Cl
Cl
Cl
P
P
Cl
Cl
P
Pd
H
Pd
Pd
H
Pd
t-Bu
t-Bu
HO
Cl
Cl
O
P
O
P
t-Bu
Cl
t-Bu
t-Bu
t-Bu
HO t-Bu
t-Bu
t-Bu
t-Bu
HO
POPd
POPd1
POPd2
Figure 1 Structure of POPd, POPd1 and POPd2
SYNTHESIS 2005, No. 14, pp 2287–2292
x
x.
x
x
.
2
0
0
5
Advanced online publication: 13.07.2005
DOI: 10.1055/s-2005-870013; Art ID: M01405SS
© Georg Thieme Verlag Stuttgart · New York

2288
R. Lerebours, C. Wolf
PAPER
Table 2 Cross-Coupling of TBAT and Aryl Halides in Watera
More importantly, the yield of 17 can be further increased
to 92% in 0.5 M NaOH at high concentration even in the
absence of TBAF or TOAF (Table 1, entry 9).
Entry Aryl halide
Product
Yield
(%)
1
1
2
3
17 92
N
Br
Br
F
Bu4N Ph Si
F
Ph
Ph
Pd(0)
N
+
N
2
17 56
18 54
Cl
N
N
1
17
N
Scheme 1 Palladium-catalyzed cross-coupling of 3-bromopyridine
and TBAT
3
CN
CN
Br
Table 1 Screening of Cross-Coupling Conditions Using TBAT and
Bromide 1a
4
4
5
6
19 87
19 73
20 90
I
MeO
MeO
Entry Catalyst
Equiv Additive
TBAT
Yield
(%)
OMe
5
Br
1
2
3
4
5
6
7
8
9
POPd (10 mol%)
2
–
20
POPd1 (10 mol%)
POPd2 (10 mol%)
POPd2 (10 mol%)
POPd2 (10 mol%)
POPd2 (10 mol%)
POPd2 (10 mol%)
POPd2 (10 mol%)
POPd2 (10 mol%)
2
–
41
OMe
6
I
2
–
61b
c
1
–
–
c
1
TBAF (2 equiv)
TBAF (2 equiv)
TBAF (2 equiv)
TBAF (2 equiv)
0.5 M NaOH
–
7
7
8
9
21 66
21 87
22 88
Br
t-Bu
t-Bu
t-Bu
2
70
71
75
92
8
2.5
5
t-Bu
I
9
2
Br
Ph
10
10
11
12
13
14
23 85
23 85
24 70
25 73
26 72
a General reaction conditions: Aryl halide (100 mg), POPd2 (10
mol%), TBAT (2.0 equiv) in deionized water (5 mL) at 135–140 °C
for 24 h in a closed vessel if not stated otherwise.
b Only 20% product was obtained after 5 h.
Br
c No product formation was observed.
11
I
Having optimized the POPd2-catalyzed NaOH-promoted
Hiyama cross-coupling procedure in water, we were able
to prepare biaryls 17–28 from various aryl halides and
TBAT in good to high yields (Table 2). Using naphthyl
bromides 9 and 10 we obtained 2-phenylnaphthalene (22),
and 1-phenylnaphthalene (23), in 88% and 85% yields, re-
spectively (entries 9 and 10). Phenylation of 2-bromoben-
zonitrile (3), and 2-bromotoluene (16), with TBAT gave
2-cyanobiphenyl (18), and 2-methylbiphenyl (28) in only
54% and 67% yields, respectively, which is probably a
consequence of steric hindrance (entries 3 and 16). As ex-
pected, aryl iodides afford better results than bromides.
For example, 3-phenylanisole (19) was obtained from 3-
iodoanisole (4) and TBAT in 87% yield, whereas the cor-
responding bromide 5 gave 19 in 73% yield (entries 4 and
5). Biphenyl, 21 was formed in 87% yield from 4-tert-bu-
tyliodobenzene (8) and in 66% yield from the correspond-
ing aryl bromide 7 (entries 7 and 8).
12
Ph
Cl
N
N
13
Cl
Ph
N
N
14
Ph
Cl
Ph
N
Ph
N
15
16
15
16
27 66
28 67
S
S
Cl
Br
a All reactions were carried out with aryl halide (100 mg), TBAT (2.0
equiv), and POPd2 (10 mol%) in 0.5 M NaOH (1 mL) at 135–140 °C
for 24 h in a closed vessel.
Synthesis 2005, No. 14, 2287–2292 © Thieme Stuttgart · New York

PAPER
Palladium–Phosphinous Acid Catalyzed Cross-Coupling of Aryl Halides
2289
Our method is also applicable to aryl chlorides albeit low- cedure requires aryl halide, two equivalents of TBAT, and
er yields are observed. Employing 3-bromopyridine (1) in POPd2 in 0.5 M aqueous NaOH solution while avoiding
the coupling reaction with TBAT provided 3-phenylpyri- the use of surfactants and organic co-solvents. We have
dine (17) in 92% yield, whereas 3-chloropyridine (7) gave thus developed a cross-coupling method that utilizes an
biaryl 17 in only 56% (Table 2, entries 1 and 2). Electron- air-stable palladium phosphinous acid in water while
deficient quinolyl chlorides 12–14 undergo cross-cou- avoiding toxic reagents such as stannanes and the use of
pling in 70–73% yields (entries 12–14). Notably, coupling hazardous organic solvents.
of electron-rich 2-chlorothiophene, 15, and TBAT affords
2-phenylthiophene (27) in 66% yield (entry 15).
All chemicals were of reagent grade. Reactions were carried out us-
ing a high pressure vessel (i.d. 31.7 cm) made of 4.0 mm Pyrex 7740
heavy wall glass and equipped with a 4 mm bore valve and Aegis
backing o-ring. Flash chromatography was carried out on Kieselgel
60 (particle size 0.032–0.063 mm). NMR spectra were obtained on
a Varian FT-NMR spectrometer at 300 MHz (1H NMR) and 75
MHz (13C NMR) using CDCl3 as the solvent. Chemical shifts are re-
ported in ppm relative to TMS. GC–MS was performed on a Fison
Although the mechanism of the palladium–phosphinous
acid catalyzed Hiyama-type coupling reaction is still un-
der investigation, we assume that the generation of a cat-
alytically active Pd(0) species proceeds via reductive
cleavage and deprotonolysis of POPd2 in the presence of
NaOH (Scheme 2). The deprotonated electron-rich Pd
catalyst undergoes oxidative addition to the aryl halide Instruments MD800 mass spectrometer equipped with a gas chro-
matograph.
followed by transmetalation and reductive elimination to
afford the desired coupling product and the regenerated
Pd(0) species. Arylsiloxanes are less reactive than their
corresponding boronic acids and organostannanes and
Coupling Procedure
A mixture of aryl halide (100 mg), POPd2 (10 mol%), and TBAT
(2 equiv) was stirred in 0.5 M NaOH (5 mL) at 135 °C for 24 h. The
usually need to be activated for transmetalation. This can
be accomplished through the formation of sp3d- or sp3d2-
hybridized silicate species using CsF or ammonium fluo-
ride additives. Accordingly, the presence of TBAF or
NaOH is expected to enhance the reactivity of hypervalent
TBAT. In addition, NaOH activates the palladium-phos-
phinous acid catalyst through deprotonation thus provid-
ing an electron-rich Pd(0) species that rapidly undergoes
oxidative addition with aryl halides.
reaction mixture was allowed to cool to r.t., quenched with water,
and extracted with Et2O. The combined organic layers were washed
with brine, dried over MgSO4, and the solvents were removed under
vacuum. The residue was purified by flash chromatography on sili-
ca gel, vide infra.
3-Phenylpyridine (17)22
Purification by chromatography on silica gel using hexanes–EtOAc
(5:1) gave 17 (90.9 mg, 92% using 1) as a colorless oil.
1H NMR (300 MHz, CDCl3): d = 7.33–7.51 (m, 4 H), 7.56–7.61 (m,
2 H), 7.88 (ddd, J = 0.6, 1.7, 7.8 Hz, 1 H), 8.59 (dd, J = 1.7, 4.7 Hz,
1 H), 8.85 (dd, J = 0.9, 2.5 Hz, 1 H).
In summary, a variety of aryl chlorides and bromides have
successfully been employed in NaOH-promoted POPd2-
catalyzed cross-coupling reactions using TBAT. This pro-
t-Bu t-Bu
Cl
Cl
HO
P
Cl
Pd
Pd
Cl
P
OH
t-Bu t-Bu
reduction,
deprotonolysis
L
O
Ph
Br
Pd
P
t-Bu
t-Bu
L
N
N
Br
L
N
L
Ph
N
Pd
Pd
L
P
L
t-Bu
P
O
t-Bu
t-Bu
O
t-Bu
F
F
Ph Si
F
Ph
Ph
Si
+
Br
Ph
Ph
F
Scheme 2 Proposed catalytic cycle of the POPd2-catalyzed cross-coupling with TBAT
Synthesis 2005, No. 14, 2287–2292 © Thieme Stuttgart · New York

2290
R. Lerebours, C. Wolf
PAPER
13C NMR (75 MHz, CDCl3): d = 123.7, 127.3, 128.3, 129.3, 134.5,
1H NMR (300 MHz, CDCl3): d = 7.26–7.45 (m, 9 H), 7.79–7.86 (m,
136.8, 138.1, 148.5, 148.6.
3 H).
EI–MS (70 eV): m/z (%) = 155 (100) [M+], 78 (5) [M+ – Ph], 77 (10)
13C NMR (75 MHz, CDCl3): d = 125.57, 125.96, 126.01, 126.22,
127.11, 127.42, 127.82, 128.07, 128.45, 130.64.
[M+ – py].
EI–MS (70 eV): m/z (%) = 204 (100) [M+], 127 (10) [M+ – Ph], 77
(20) [Ph].
2-Cyanobiphenyl (18)23
Purification by chromatography on silica gel using hexanes–Et2O
(5:1) gave 18 (53 mg, 54%) as a colorless oil.
1H NMR (300 MHz, CDCl3): d = 7.42–7.59 (m, 7 H), 7.65 (ddd,
J = 1.4, 7.7, 7.7 Hz, 1 H), 7.77 (dd, J = 0.8, 7.7 Hz, 1 H).
4-Phenylquinoline (24)29
Purification by chromatography on silica gel using hexanes–
EtOAc–Et3N (100:10:1) gave 24 (88.2 mg, 70%) as a yellow oil.
13C NMR (75 MHz, CDCl3): d = 111.5, 118.9, 127.7, 128.9, 130.3,
133.0, 133.9, 138.3, 145.7.
1H NMR (300 MHz, CDCl3): d = 7.34 (d, J = 4.4 Hz, 1 H), 7.50–
7.52 (m, 6 H), 7.73 (dd, J = 7.0, 8.2 Hz, 1 H), 7.92 (d, J = 7.0 Hz, 1
H), 8.18 (d, J = 8.2 Hz, 1 H), 8.95 (d, J = 4.4 Hz, 1 H).
EI–MS (70 eV): m/z (%) = 179 (100) [M+], 153 (25) [M+ – CN], 76
(37) [M+ – CN – Ph].
13C NMR (75 MHz, CDCl3): d = 121.5, 126.1, 126.8, 128.6, 128.8,
129.5, 129.7, 130.0, 138.2, 148.7, 148.8, 150.0.
EI–MS (70 eV): m/z (%) = 205 (85) [M+], 204 (100) [M+ – H], 77
(10) [Ph].
3-Phenylanisole (19)24
Flash Chromatography using hexanes–EtOAc (5:1) gave 19 (67.2
mg, 87% from 4) as a clear oil.
1H NMR (300 MHz, CDCl3): d = 3.87 (s, 3 H) 6.91 (dd, J = 2.1, 8.6
Hz, 1 H), 7.14 (m, 2 H), 7.36 (m, 2 H), 7.44 (d, J = 7.4 Hz, 2 H),
7.60 (dd, J = 1.4, 7.2 Hz, 2 H).
2-Methyl-4-phenylquinoline (25)
Purification by chromatography on silica gel using hexanes–Et2O–
Et3N (50:50:1) gave 25 (84 mg, 73%) as a colorless oil.
13C NMR (75 MHz, CDCl3): d = 55.60, 112.87, 113.10, 113.14,
119.86, 127.49, 127.36, 127.56, 128.88, 129.89, 138.08.
EI–MS (70 eV): m/z (%) = 184 (40) [M+], 153 (100) [M+ – Me], 77
(10) [Ph].
1H NMR (300 MHz, CDCl3): d = 2.78 (s, 3 H), 7.23 (s, 1 H), 7.43
(ddd, J = 1.4, 7.6, 8.5 Hz, 1 H), 7.47–7.51 (m, 5 H), 7.69 (ddd, J =
1.4, 7.6, 8.4 Hz, 1 H), 7.86 (dd, J = 1.4, 8.4 Hz, 1 H), 8.08 (dd, J =
1.4, 8.5 Hz, 1 H).
13C NMR (75 MHz, CDCl3): d = 25.4, 122.1, 125.0, 125.5, 125.6,
128.2, 128.5, 128.9, 129.2, 129.5, 138.0, 148.2, 148.3, 158.3.
3,5-Dimethylbiphenyl (20)25
Flash chromatography using hexanes gave 20 (70.5 mg, 90%) as a
white oil.
1H NMR (300 MHz, CDCl3): d = 2.37 (s, 6 H), 6.99 (s, 1 H), 7.29
(s, 2 H), 7.35 (d, J = 7.5 Hz, 1 H), 7.47 (d, J = 7.5 Hz, 2 H), 7.64 (d,
J = 7.5 Hz, 2 H).
EI–MS (70 eV): m/z (%) = 219 (100) [M+], 204 (50) [M+ – Me], 142
(2) [M+ – Ph], 127 (10) [M+ – Me – Ph].
Anal. Calcd for C16H13N: C, 87.64; H, 5.98; N, 6.39. Found: C,
87.52; H, 5.82; N, 6.35.
13C NMR (75 MHz, CDCl3): d = 21.4, 125.1, 127.0, 127.2, 128.6,
2,4-Diphenylquinoline (26)30
128.9, 138.2, 141.3, 141.5.
Purification by chromatography on silica gel using hexanes–
EtOAc–Et3N (100:20:1) gave 26 (90.6 mg, 72%) as colorless crys-
tals; mp 109–111 °C.
1H NMR (300 MHz, CDCl3): d = 7.43–7.58 (m, 9 H), 7.70–7.76 (dd,
J = 7.1, 8.2 Hz, 1 H), 7.82 (s, 1 H), 7.90 (d, J = 8.2 Hz, 1 H), 8.17–
8.22 (m, 3 H).
13C NMR (75 MHz, CDCl3): d = 119.67, 126.02, 126.68, 127.98,
128.76, 128.97, 129.19, 129.69, 129.84, 129.96, 130.60, 138.90,
140.12, 149.29, 149.55, 157.27.
EI–MS (70 eV): m/z (%) = 182 (70) [M+], 167 (10) [M+ – Me], 152
(100) [M+ – 2 × Me], 77 (10, Ph).
4-tert-Butylbiphenyl (21)26
Purification by chromatography on silica gel using hexanes provid-
ed 21 (68.3 mg, 87%) as a yellow oil.
1H NMR (300 MHz, CDCl3): d = 1.36 (s, 9 H), 7.32 (t, J = 7.5 Hz,
1 H), 7.39–7.49 (m, 4 H), 7.53–7.61 (m, 4 H).
13C NMR (75 MHz, CDCl3): d = 31.74, 34.88, 125.81, 126.83,
126.96, 127.29, 127.35, 128.92, 138.60, 141.42, 150.67.
EI–MS (70 eV): m/z (%) = 280 (100) [M+], 204 (80) [M+ – Ph], 127
(10) [M+ – 2 × Ph].
EI–MS (70 eV): m/z (%) = 210 (60) [M+], 195 (100) [M+ – Me], 153
2-Phenylthiophene (27)31
Flash chromatography (hexanes) gave 27 (90.1 mg, 66%) as a col-
(35) [M+ – t-Bu].
orless oil.
2-Phenylnaphthalene (22)27
Purification by chromatography on silica gel using hexanes–CH2Cl2
(10:1) afforded 22 (87.3 mg, 88%) as white crystals; mp 97–100 °C.
1H NMR (300 MHz, CDCl3): d = 7.37 (m, 1 H), 7.45–7.50 (m, 4 H),
1H NMR (300 MHz, CDCl3): d = 7.09 (dd, J = 5.0, 3.8 Hz 1 H), 7.27
(d, J = 5.0 Hz, 1 H), 7.32 (d, J = 3.8 Hz, 1 H), 7.39 (dd, J = 7.8 Hz,
J = 7.2 Hz, 2 H), 7.44 (d, J = 7.8 Hz, 1 H), 7.62 (d, J = 7.2 Hz, 2 H).
7.71–7.76 (m, 3 H), 7.81–7.91 (m, 3 H), 8.03 (s, 1 H).
13C NMR (75 MHz, CDCl3): d = 123.0, 124.7, 125.9, 127.4, 128.0,
128.8, 134.3, 144.4.
EI–MS (70 eV): m/z (%) = 160 (100) [M+], 77 (10) [Ph].
13C NMR (75 MHz, CDCl3): d = 126.0, 126.2, 126.4, 126.7, 127.8,
127.9, 128.1, 128.7, 128.9, 129.3, 133.1, 134.1, 138.9, 141.5.
EI–MS (70 eV): m/z (%) = 204 (100) [M+], 127 (5) [M+ – Ph], 77
(3) [Ph].
2-Methylbiphenyl (28)24
Flash chromatography (hexanes) gave 28 (66.2 mg, 67%) as a clear
oil.
1-Phenylnaphthalene (23)28
Flash chromatography (hexanes) gave 23 (84.3 mg, 85% from 10)
as a white oil.
1H NMR (300 MHz, CDCl3): d = 2.28 (s, 3 H), 7.22–7.44 (m, 9 H).
13C NMR (75 MHz, CDCl3): d = 14.49, 125.93, 126.92, 127.41,
128.22, 128.73, 129.36, 129.96, 130.46, 136.01, 136.42.
Synthesis 2005, No. 14, 2287–2292 © Thieme Stuttgart · New York

PAPER
Palladium–Phosphinous Acid Catalyzed Cross-Coupling of Aryl Halides
2291
EI–MS (70 eV): m/z (%) = 168 (10) [M+], 153 (100) [M+ – Me], 77
(12) (a) Badone, D.; Baroni, M.; Cardamone, R.; Ielmini, A.;
(10) [Ph].
Guzzi, U. J. Org. Chem. 1997, 62, 7170. (b) Uozomi, Y.;
Danjo, H.; Hayashi, T. J. Org. Chem. 1999, 64, 3384.
(c) Gelpke, A. E. S.; Veerman, J. J. N.; Goedheijt, M. S.;
Kamer, P. C. J.; van Leeuwen, P. W. N. M.; Hiemstra, H.
Tetrahedron 1999, 55, 6657. (d) Paetzold, E.; Oehme, G. J.
Mol. Catal. A: Chem. 2000, 152, 69. (e) LeBlond, C. R.;
Andrews, A. T.; Sun, Y.; Sowa, J. R. Org. Lett. 2001, 3,
1555. (f) Shaughnessy, K. H.; Booth, R. S. Org. Lett. 2001,
3, 2757. (g) Dupuis, C.; Adiey, K.; Charruault, L.; Michelet,
V.; Savignac, M.; Genet, J.-P. Tetrahedron Lett. 2001, 42,
6523. (h) Ueda, M.; Nishimura, M.; Miyaura, N. Synlett
2000, 856. (i) Botella, L.; Nájera, C. Angew. Chem. Int. Ed.
2002, 41, 179. (j) Botella, L.; Nájera, C. J. Organomet.
Chem. 2002, 663, 46. (k) Alonso, D. A.; Nájera, C.;
Pacheco, M. A. J. Org. Chem. 2002, 67, 5588. (l) Bedford,
R. B.; Blake, M. E.; Butts, C. P.; Holder, D. Chem. Commun.
2003, 466. (m) Li, C.-J. Angew. Chem. Int. Ed. 2003, 42,
4856.
Acknowledgment
We thank Combiphos Catalysts, Inc., New Jersey (www.combi-
phos.com) for POPd, POPd1 and POPd2.
References
(1) (a) Suzuki, A. J. Organomet. Chem. 1999, 576, 147.
(b) Grushin, V. V.; Alper, H. Top. Organomet. Chem. 1999,
3, 193. (c) Firooznia, F.; Gude, C.; Chan, K.; Satoh, Y.
Tetrahedron Lett. 1998, 39, 3985. (d) Littke, A. F.; Dai, C.;
Fu, G. C. J. Am. Chem. Soc. 2000, 122, 4020.
(e) Tsukamoto, H.; Sato, M.; Kondo, Y. Chem. Commun.
2004, 1200.
(2) (a) Dai, C.; Fu, G. J. Am. Chem. Soc. 2001, 123, 2719.
(b) Wolfe, J. P.; Singer, R. A.; Yang, B. H.; Buchwald, S. L.
J. Am. Chem. Soc. 1999, 121, 9550.
(13) Wuellner, G.; Jaensch, H.; Kannenberg, S.; Schubert, F.;
Boche, G. Chem. Commun. 1998, 1509.
(3) (a) Huang, J.; Nolan, S. P. J. Am. Chem. Soc. 1999, 121,
9889. (b) Yamamura, M.; Moritani, I.; Murahashi, S. I. J.
Organomet. Chem. 1975, 91, C39. (c) Megishi, E. Metal
Catalyzed Cross-Coupling Reactions; Wiley-VCH:
Weinheim, 1998, 13–65.
(14) (a) Amatore, C.; Blart, E.; Genet, J. P.; Jutand, A.; Lemaire-
Audoire, S.; Savignac, M. J. Org. Chem. 1995, 60, 6829.
(b) Hessler, A.; Stelzer, O.; Dibowski, H.; Worm, K.;
Schmidtchen, F. P. J. Org. Chem. 1997, 62, 2362.
(c) Lopez-Deber, M. P.; Castedo, L.; Granja, J. R. Org. Lett.
2001, 3, 2823.
(15) (a) Roshchin, A. I.; Bumagin, N. A.; Beletskaya, I. P.
Tetrahedron Lett. 1995, 36, 125. (b) Rai, R.; Aubrecht, K.
B.; Collum, D. B. Tetrahedron Lett. 1995, 36, 3111.
(c) Kang, S.-K.; Baik, T.-G.; Song, S.-Y. Synlett 1999, 327.
(16) Genet, J. P.; Blart, E.; Savignac, M. Synlett 1992, 715.
(17) (a) Genet, P. J.; Savignac, M. J. Organomet. Chem. 1999,
576, 305. (b) Takami, K.; Yorimitsu, H.; Shinokubo, H.;
Matsubara, S.; Oshima, K. Org. Lett. 2001, 3, 1997.
(c) Najera, C.; Gil-Molto, J.; Karlstrom, S.; Falvello, L. R.
Org. Lett. 2003, 5, 1451.
(4) (a) Littke, A. F.; Fu, G. C. J. Org. Chem. 1999, 64, 10.
(b) Heck, R. F. Palladium Reagents in Organic Synthesis;
Academic Press: London, 1990. (c) Beletskaya, I. P.;
Cheprakov, A. V. Chem. Rev. 2000, 100, 3009. (d) de
Meijere, A.; Meyer, F. E. Angew. Chem., Int. Ed. Engl. 1995,
33, 2379. (e) Schnyder, A.; Aemmer, T.; Indolese, A. F.;
Pittlekow, U.; Studer, M. Adv. Synth. Catal. 2002, 344, 495.
(5) (a) Casado, A. L.; Espinet, P. J. Am. Chem. Soc. 1998, 120,
8978. (b) Stille, J. K. Angew. Chem., Int. Ed. Engl. 1986, 25,
508. (c) Farina, V.; Krishnamurthy, V.; Scott, W. J. Org.
React. (N. Y.) 1997, 50, 1. (d) Bedford, R. B.; Cazin, C. S.
J.; Hazalwood, S. M. Chem. Commun. 2002, 32, 2608.
(6) Bond dissociation energies for PhX; X = Cl: 96 kcal/mol,
X = Br: 81 kcal/mol, X = I: 65 kcal/mol.
(18) (a) Uozomi, Y.; Nakai, Y. Org. Lett. 2002, 4, 2997.
(b) Leadbeater, N. E.; Marco, M. J. Org. Chem. 2003, 68,
888.
(7) (a) Andrus, M. B.; Song, C. Org. Lett. 2001, 3, 3761.
(b) Littke, A. F.; Dai, C.; Fu, G. C. J. Am. Chem. Soc. 2000,
122, 4020. (c) Fu, G. C.; Littke, A. F. Angew. Chem. Int. Ed.
2002, 41, 4176. (d) Littke, A. F.; Schwarz, L.; Fu, G. C. J.
Am. Chem. Soc. 2002, 124, 6343. (e) Su, W.; Urgaonkar, S.;
Verkade, J. G. Org. Lett. 2004, 6, 1421. (f) Walker, S. D.;
Barder, T. E.; Martinelli, J. R.; Buchwald, S. L. Angew.
Chem. Int. Ed. 2004, 43, 1871. (g) Schnyder, A.; Indolese,
A. F.; Studer, M.; Blaser, H. U. Angew. Chem. Int. Ed. 2002,
41, 3668.
(8) (a) Freeman, G. G. Silicones: An Introduction to Their
Chemistry and Applications; Chapel River Press: UK, 1962,
99–104. (b) Hatanaka, Y.; Hiyama, T. Synlett 1991, 845.
(9) (a) Lee, J.-Y.; Fu, G. C. J. Am. Chem. Soc. 2003, 125, 5616.
(b) Nishihara, Y.; Ando, J.; Kato, T.; Mori, A.; Hiyama, T.
Macromolecules 2000, 33, 2779.
(10) (a) DeShong, P.; Mowery, M. J. J. Org. Chem. 1999, 64,
1684. (b) Mowery, M. E.; DeShong, P. Org. Lett. 1999, 1,
2137. (c) Lee, H. M.; Nolan, S. P. Org. Lett. 2000, 2, 2053.
(d) Mowery, M. J.; DeShong, P. J. Org. Chem. 1999, 64,
3266.
(11) (a) Lee, H. M.; Nolan, S. P. Org. Lett. 2000, 2, 2053.
(b) DeShong, P.; Handy, C. J.; Mowery, M. Pure Appl.
Chem. 2000, 72, 1655. (c) Riggleman, S.; DeShong, P. J.
Org. Chem. 2003, 68, 8106.
(19) (a) Murata, M.; Suzuki, K.; Watanabe, S.; Masuda, Y. J.
Org. Chem. 1997, 62, 8569. (b) Murata, S.; Watanabe, S.;
Masuda, Y. Tetrahedron Lett. 1999, 40, 9255. (c)Denmark,
S. E.; Amishiro, N. J. Org. Chem. 2003, 68, 6997.
(20) (a) Oi, S.; Honma, Y.; Inoue, Y. Org. Lett. 2002, 4, 667.
(b) Huang, T. S.; Li, C. J. Chem. Commun. 2001, 2348.
(c) Murata, M.; Shimazaki, R.; Watanabe, S.; Masuda, Y.
Synthesis 2001, 2231.
(21) (a) Li, G. Y. Angew. Chem. Int. Ed. 2001, 40, 1513. (b) Li,
G. Y.; Zheng, G.; Noonan, A. F. J. Org. Chem. 2001, 66,
8677. (c) Li, G. Y. J. Org. Chem. 2002, 67, 3643. (d) Wolf,
C.; Lerebours, R. J. Org. Chem. 2003, 68, 7077. (e) Wolf,
C.; Lerebours, R.; Tanzini, E. H. Synthesis 2003, 2069.
(f) Yang, W.; Wang, Y.; Corte, J. R. Org. Lett. 2003, 5,
3131. (g) Wolf, C.; Lerebours, R. J. Org. Chem. 2003, 68,
7551. (h) Wolf, C.; Lerebours, R. Org. Lett. 2004, 6, 1147.
(i) Wolf, C.; Lerebours, R. Org. Biomol. Chem. 2004, 2,
2161.
(22) Littke, A. F.; Schwarz, L.; Fu, G. C. J. Am. Chem. Soc. 2002,
124, 6343.
(23) Riguet, E.; Alami, M.; Cahiez, G. J. Organomet. Chem.
2001, 624, 376.
(24) Navarro, O.; Kelly, R. A.; Nolan, S. P. J. Am. Chem. Soc.
2003, 125, 16194.
(25) Bei, X.; Turner, H. W.; Weinberg, W. H.; Guram, A. S. J.
Org. Chem. 1999, 64, 6797.
Synthesis 2005, No. 14, 2287–2292 © Thieme Stuttgart · New York

2292
R. Lerebours, C. Wolf
PAPER
(26) Mino, T.; Shirae, Y.; Sakamoto, M.; Fujita, T. Synlett 2003,
882.
(29) Karikomi, M.; Tsukada, H.; Toda, T. Heterocycles 2001, 55,
1249.
(27) Choudary, B. M.; Madhi, S.; Chowdari, N. S.; Kantam, M.
L.; Sreedhar, B. J. Am. Chem. Soc. 2002, 124, 14127.
(28) Molander, G. A.; Biolatto, B. Org. Lett. 2002, 4, 1867.
(30) Song, S. J.; Cho, S. J.; Park, D. K.; Kwon, T. W.; Jenekhe,
S. A. Tetrahedron Lett. 2003, 44, 255.
(31) Demir, A. S.; Reis, O.; Emrullahoglu, M. J. Org. Chem.
2004, 68, 578.
Synthesis 2005, No. 14, 2287–2292 © Thieme Stuttgart · New York