A novel palladium catalyst for cross-coupling of allyl acetates with arylboronic acids

Article abstract of DOI:10.1002/1099-0690(200208)2002:15<2445::AID-EJOC2445>3.0.CO;2-S

The palladium-catalyzed coupling reactions of various arylboronic acids and allylic acetates take place readily under mild conditions. The choice of ligand in the palladium catalyst and the solvent are critical to the yields of coupled products. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.

Full text of DOI:10.1002/1099-0690(200208)2002:15<2445::AID-EJOC2445>3.0.CO;2-S

FULL PAPER
A Novel Palladium Catalyst for Cross-Coupling of Allyl Acetates with
Arylboronic Acids
[a]
[b][‡]
and Genevi e` ve Balme*[a]
Didier Bouyssi, Vincent Gerusz,*
Keywords: Palladium / Catalysis / Allylation / Boronic acids / Cross-coupling
The palladium-catalyzed coupling reactions of various aryl-
boronic acids and allylic acetates take place readily under
mild conditions. The choice of ligand in the palladium cata-
lyst and the solvent are critical to the yields of coupled prod-
ucts.
( Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany,
2002)
Introduction
availability of allylic alcohols, we decided to focus our study
on allylic acetates (Scheme 1).
Over the past twenty years, the palladium-catalyzed
coupling of aryl-, vinyl- and alkylboronic acids with aryl
and vinyl bromides, iodides and triflates (Suzuki coup-
[
1]
ling) has gained in popularity due to the broad functional
group tolerance, the availability of boronic acid substrates
and the lack of toxic by-products. On the other hand, palla-
dium() complexes have been shown to catalyze a wide vari-
ety of synthetically useful substitutions of allylic substrates
Scheme 1
We would now like to report a novel palladium catalyst
system which can efficiently cross-couple allylic acetates
with a variety of arylboronic acids at room temperature un-
der neutral conditions.
[2]
with stabilized carbon nucleophiles. Rather surprisingly,
however, few studies[ on the use of boronic acids as nucle-
ophiles in these palladium-catalyzed allylic reactions have
3]
[
3a] Results and Discussion
been reported so far. The first reported low yields (12%),
along with the concern that acetate and phosphane ligands
We first investigated various experimental conditions to
carry out the model reaction of cinnamyl acetate (1) with
phenylboronic acid (2). Since our main objective was to per-
form the reaction under the mildest possible conditions, we
[
4]
could slow down the crucial transmetallation step, might
explain this slow development. However, two recent articles
initiated a breakthrough in this field. The first one by Mor-
[
3b]
eno-Ma n˜ as’ group
reported the coupling of arylboronic
decided to avoid the use of a base, instead we resorted to a
fluoride source to activate the boronic acid reagent as al-
acids with allyl bromides under basic conditions in re-
fluxing benzene (58Ϫ91% yield), while the second one by
[
6]
ready reported for the Suzuki coupling. The fluoride
source indeed proved necessary as stirring equivalent molar
amounts of 1 and 2 with 5 mol % of [Pd (dba) ] in refluxing
Hayashi and co-workers[
3c]
described the reaction of
phenylboronic acid with allylic acetates under basic condi-
tions in water at room temperature using a resin-supported
palladium catalyst (45Ϫ99% yield).[ Due to the ready
2
3
THF for 4 h under argon led to complete recovery of the
starting material, whereas using CsF or KF allowed the re-
5]
action to occur with excellent regio- and stereoselectivity
Laboratoire de Chimie Organique 1, CNRS UMR 5622, yielding 1,3-diphenyl-(E)-propene (3) as the exclusive cross-
[
a]
Universit e´ Claude Bernard, Lyon I, CPE,
coupling product (Table 1). The use of cesium as a coun-
4
3, Bd du 11 Novembre 1918, 69622 Villeurbanne, France
Fax: (internat.) ϩ33-(0)47/2431-214
E-mail: balme@univ-lyon1.fr
Aventis Cropscience,
terion was more beneficial than potassium (entries 1 and 2;
and 4). However, increasing the amount of KF to 2.6
9
[
[
b]
‡]
equivalents led to an increase of yields matching the ones
obtained with more expensive CsF (entries 4,6 and 9; 5 and
1
4 /20 rue Baizet, 69623 Lyon, France
Current address: Bio Numerik Pharmaceuticals Inc.,
8
[
7]
122 Datapoint Drive Suite 400, San Antonio, Texas 78229, 10). [PdCl
(TFP)
]
proved to be the best catalyst (entries
2
2
USA
4,3,7 and 8; 5 and 6; 1 and 9) while methanol was found to
Eur. J. Org. Chem. 2002, 2445Ϫ2448  WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002 1434Ϫ193X/02/0815Ϫ2445 $ 20.00ϩ.50/0
2445

D. Bouyssi, V. Gerusz, G. Balme
FULL PAPER
Table 1. Optimization of reaction conditions
Entry
Catalyst[a]
PhB(OH)
equiv.)
2
Fluoride source
(equiv.)
Solvent
[temp. (°C)]
Yield (%)[b]
time (h)
(
1
2
3
4
5
6
7
8
9
[Pd
2
2
dba
dba
3
3
]
]
1.1
1.1
1.1
1.1
1.3
1.3
1.1
1.1
1.3
1.1
1.3
1.3
1.3
1.3
1.3
CsF (1.1)
KF (1.1)
KF (2.2)
KF (2.2)
KF (2.6)
KF (2.6)
KF (2.2)
KF (2.2)
CsF (1.3)
CsF (2.2)
KF (2.6)
KF (2.6)
KF (2.6)
KF (2.6)
KF (2.6)
THF
52 (4 h)
(
60 °C)
THF
60 °C)
THF
60 °C)
THF
room temp.)
THF
room temp.)
THF
room temp.)
THF
room temp.)
THF
60 °C)
THF
room temp.)
THF
room temp.)
acetone
room temp.)
MeOH
room temp.)
MeOH
room temp.)
MeOH
room temp.)
MeOH
room temp.)
[Pd
low (10 h)
low (4 h)
52 (22 h)
72 (22 h)
76 (22 h)
52 (24 h)
Ͻ 5 (7 h)
75 (8 h)
(
2
[Pd(OAc) ]
(
[PdCl
[PdCl
[PdCl
[PdCl
[PdCl
[PdCl
[PdCl
[PdCl
[PdCl
2
2
2
2
2
2
2
2
2
(TFP)
(PPh
(TFP)
(o-tol)
(PhCN)
(TFP)
(PPh
2
]
(
3 2
) ]
(
2
]
(
2
]
(
2
]
(
2
]
(
10
11
12
13
14
15
3
)
2
]
74 (16 h)
75 (19 h)[c]
87 (4 h)
(
(TFP)
(TFP)
2
2
]
(
] (1.25%)
(
[Pd(OAc)
2
]
low (24 h)
98 (3 h)
(
[PdCl
[PdCl
2
2
(TFP)
(TFP)
2
2
]( 0.7%)
] (0.1%)
(
86 (24 h)
(
[
a]
All reactions were performed with 2.5 mol % of catalyst except when mentioned otherwise. [b] Isolated yield. [c] Accompanied by 15%
of allyl acetate dimerization product.[
8]
be the solvent of choice (entries 6,11 and 14). Interestingly was extended to cyclic and acyclic secondary allyl acetates.
the catalyst concentration could be lowered to 0.1 mol % (entries 12, 13 and 14)
with increased reaction times and slightly decreasing yields
entries 14 and 15).
In summary, we have devised a novel catalyst system gen-
erally applicable to cross-coupling of a wide variety of
(
The best experimental conditions (entry 14, Table 1) were boronic acids and allylic acetates under extremely mild,
then applied to the cross-coupling reaction of different neutral conditions.
boronic acids and various allyl acetates (Table 2). Again,
the reaction displayed excellent regio- and stereoselectivity
since only one coupling product of exclusive (E) double Experimental Section
bond geometry was observed, in which the aromatic moiety
of the boronic acid reagent had displaced the less hindered General Remarks: Unless otherwise noted, all reactions were car-
site of the putative π-allyl complex intermediate[ (entries ried out under a nitrogen atmosphere using standard syringe, can-
nula, and septum techniques. Commercially available reagents were
9]
1
1
Ϫ9 and 14). Electron-rich boronic acids (entries 6,9 and
1) and, more remarkably, sterically hindered substrates
used as purchased. Tetrahydrofuran was dried by distillation over
sodium/benzophenone ketyl. Other solvents were commercial an-
hydrous grades and were used without further drying. Thin-layer
chromatography was carried out on Merck silica 60/F-254 alumi-
nium-backed plates. Flash chromatography was performed using
Merck silica gel 60 (40Ϫ63 µm). NMR spectra were recorded in
(entry 7) as well as electron-deficient aromatic rings (entries
2,3,4,5, 10 and 13) are well tolerated. In the case of 2-furyl-
boronic acid (entry 8) the reaction was too slow or did not
proceed in methanol, yielding instead (3-methoxy-1-pro-
penyl)benzene.
[
10]
However, switching to THF as solvent
3
CDCl . Chemical shifts (δ) are quoted in parts per million and
solved this problem, allowing the heterocyclic boronic acid coupling constants in Hz. Melting points were measured with a
to form in the desired fashion (entry 9). Finally, the reaction Büchi apparatus and are uncorrected.
2446
Eur. J. Org. Chem. 2002, 2445Ϫ2448

Cross-Coupling of Allyl Acetates with Arylboronic Acids
Table 2. Cross-coupling of allyl acetates with arylboronic acids
FULL PAPER
[
a]
[b]
All reactions were run at room temperature in MeOH using 0.7 mol % of [PdCl
2
(TFP)
2
] as catalyst.
The reaction was carried out
[
c]
[d]
at 40 °C. The isolated product resulted from attack of MeOH onto π-allyl palladium complex. THF was used instead of MeOH.
General Procedure for the Reaction of Boronic Acids and Allylic
Acetates: The allylic acetate (1 mmol) and [PdCl (TFP)
0.007 mmol) were added successively to a solution of KF
2.6 mmol) and boronic acid (1.3 mmol) in 5 mL of MeOH. The
resulting mixture was stirred for the appropriate time (see Table 2)
until completion (TLC monitoring). The reaction was then
quenched with water and extracted with diethyl ether. The organic
2
2
]
(
(
layer was washed with brine, dried over MgSO
4
and concentrated
Eur. J. Org. Chem. 2002, 2445Ϫ2448
2447

D. Bouyssi, V. Gerusz, G. Balme
FULL PAPER
11, 513Ϫ520. [1b] Y. Hoshino, N. Miyaura, A. Suzuki, Bull.
Chem. Soc. Jpn. 1988, 61, 3008Ϫ3010. [ N. Miyaura, T. Ishi-
yama, H. Sasaki, M. Ishikawa, M. Satoh, A. Suzuki, J. Am.
in vacuo. The residue was purified by column chromatography on
silica gel with diethyl ether/petroleum ether as the eluent to afford
the coupling product.
1c]
[1d]
Chem. Soc. 1989, 111, 314Ϫ321. For reviews see:
A. Suzuki,
A. R. Martin, Y.
1
13
[3b]
3c,[11a] 3f,[3b]
[1e]
The H and C NMR spectra of compounds 3a,
Pure Appl. Chem. 1991, 63, 419Ϫ422.
Yang, Acta Chem. Scand. 1993, 47, 221Ϫ230. [ N. Miyaura,
A. Suzuki, Chem. Rev. 1995, 95, 2457Ϫ2483.
2] [2a]
1f]
[
11b]
[11c]
[11d]
[11e]
[11f]
3g,
3h,
3i,
3j,
3k
were as previously reported.
[
3-(4-Acetylphenyl)-1-phenyl-1-propene (3b): Colorless oil (210 mg,
B. M. Trost, P. E. Strege, J. Am. Chem. Soc. 1975, 97,
2534Ϫ2535. [ B. M. Trost, T. R. Verhoeven, J. Am. Chem.
2b]
8
9%) (diethyl ether/petroleum ether, 4:1). IR (NaCl): ν˜ ϭ 3080
cm , 3026, 2918, 2918, 1682, 1605, 1571, 1411, 1356, 1266, 965,
[
2c]
Ϫ1
Soc. 1980, 102, 4730Ϫ4743. For reviews see:
B. M. Trost,
Acc. Chem. Res. 1980, 13, 385Ϫ393. [ T. Yamamoto, O. Saito,
2d]
1
8
(
28, 749, 694. H NMR (300 MHz, CDCl
d, J ϭ 6.8 Hz, 2 H), 6.37 (dt, J ϭ 15.8, 6.8 Hz, 1 H), 6.51 (d, J ϭ
5.8 Hz, 1 H), 7.22Ϫ7.43 (m, 7 H), 7.95 (d, J ϭ 8.3 Hz, 2 H) ppm.
3
): δ ϭ 2.62 (s, 3 H), 3.63
[
2e]
A. Yamamoto, J. Am. Chem. Soc. 1981, 103, 5600Ϫ5602.
G. Consiglio, R. M. Waymouth, Chem. Rev. 1989, 89,
1
[2f]
257Ϫ276.
B. M. Trost, D. L. Van Vranken, Chem. Rev. 1996,
1
3
C NMR (CDCl
3
, 75 MHz): δ ϭ 26.6, 39.3, 126.2, 127.4, 127.9,
9
6, 395Ϫ422.
1
28.6, 128.7, 128.9, 131.9, 135.4, 137.2, 145.9, 197.8. CI-HRMS
[3] [3a]
N. Miyaura, K. Yamada, H. Suginome, A. Suzuki, J. Am.
ϩ
[3b]
(for [MH ]) calcd. for C17
H16O: 237.12794; found 237.12744.
Chem. Soc. 1985, 107, 972Ϫ980.
M. Moreno-Ma n˜ as, F. Pa-
[
3c]
juelo, R. Pleixats, J. Org. Chem. 1995, 60, 2396Ϫ2397.
Y.
3-(3-Nitrophenyl)-1-phenyl-1-propene (3d): White solid (203 mg,
Uozumi, H. Danjo, T. Hayashi, J. Org. Chem. 1999, 64,
8
5%) (diethyl ether/petroleum ether, 9:1), m.p. 50Ϫ51 °C. IR (KBr):
[3d]
3384Ϫ3388.
A palladium-catalyzed phenylation of allylic
Ϫ1
ν˜ ϭ 3025 cm , 2907, 1560, 1534, 1347, 971, 746, 734, 694, 686.
acetates using tetraphenylborate anion has also been reported:
J-Y. Legros, J-C. Fiaud, Tetrahedron Lett. 1990, 31,
7453Ϫ7456.
1
3
H NMR (CDCl , 300 MHz): δ ϭ 3.68 (d, J ϭ 6.8 Hz, 2 H), 6.35
(
(
dt, J ϭ 15.8, 6.8 Hz, 1 H), 6.53 (d, J ϭ 15.8 Hz, 1 H), 7.24Ϫ7.42
m, 5 H), 7.50 (dd, J ϭ 7.8, 7.8 Hz, 1 H), 7.61 (d, J ϭ 7.5 Hz, 1
[
[
4]
L. S. Hegedus, in Organometallic Synthesis (Ed.: M. Schlosser),
Wiley 1994, p.434.
13
H), 8.12 (m, 2 H) ppm. C NMR (CDCl
3
, 75 MHz): δ ϭ 39.3,
5] [5a]
Also related is the nickel-catalyzed asymmetric cross-coup-
1
1
2
21.9, 123.9, 126.6, 127.6, 128.0, 129.0, 129.8, 132.9, 135.3, 137.3,
ling reaction of allylic carbonates with lithium arylborates: Y.
42.7, 148.8. EI-HRMS calcd. for C15
39.0948.
2
H13NO : 239.0946; found
Kobayashi, R. Mizojiri, E. Ikeda, J. Org. Chem. 1996, 61,
5391Ϫ5499, as well as the nickel-catalyzed reaction of allyl
acetates with arylboronic acids with DIBAL-H under basic
conditions at THF reflux: [ K-G. Chung, Y. Miyake, S. Ue-
mura, J. Chem. Soc., Perkin Trans. 1 2000, 15Ϫ18.
3
-(3,5-Ditrifluoromethylphenyl)-1-phenyl-1-propene (3e): White
5b]
solid (166 mg, 66%) (petroleum ether), m.p. 64.5Ϫ65.5 °C. IR
Ϫ1
(
KBr): ν˜ ϭ 3022 cm , 1622, 1376, 1277, 1170, 1116, 971, 889, 757.
H NMR (300 MHz, CDCl
[6]
S. W. Wright, D. L. Hageman, L. D. McClure, J. Org. Chem.
1
3
): δ ϭ 3.71 (d, J ϭ 6.8 Hz, 2 H), 6.35
1994, 59, 6095Ϫ6097.
[
7] [7a]
(
(
dd, J ϭ 15.8, 6.8 Hz, 1 H), 6.53 (d, J ϭ 15.8 Hz, 1 H), 7.27Ϫ7.46
m, 5 H), 7.75 (s, 2 H), 7.81 (s, 1 H) ppm. C NMR (CDCl
Dichlorobis(tri-2-furylphosphane)palladium() was pre-
pared from K PdCl and tri-2-furylphosphane: C. M. Hettrick,
13
3
,
2
4
7
1
1
5 MHz): δ ϭ 39.3, 120.8 (q, J ϭ 3.7 Hz), 123.8 (q, J ϭ 273 Hz),
26.7, 127.0, 128.1, 129.1 (q, J ϭ 1.3 Hz), 132.2 (q, J ϭ 3 3.0 Hz),
33.3, 137.2, 143.1. EI-HRMS calcd. for C17 : 330.08453;
W. J. Scott, J. Am. Chem. Soc. 1991, 113, 4903Ϫ4910. For re-
ports on the use of tri-2-furylphosphane as a stabilizing ligand
in palladium-catalyzed coupling reactions, see: [ V. Farina, S.
7b]
12 6
H F
R. Baker, D. A. Benigni, C. Sapino, Tetrahedron Lett. 1988, 29,
found 330.08452.
5
739Ϫ5742. [ S. Decortiat, M. Cavicchioli, D. Bouyssi, J.
7c]
[
7d]
Gore, G. Balme, Tetrahedron 1996, 52, 11463Ϫ11478.
H.
3-(4-Acetylphenyl)cyclohexene (3l): Colorless oil (106 mg, 53%) (di-
Ϫ1
Nüske, M. Noltemeyer, A. de Meijere, Angew. Chem. Int. Ed.
2001, 40, 3411Ϫ3413.
8]
ethyl ether/petroleum ether, 9:1). IR (NaCl): ν˜ ϭ 3019 cm , 2929,
857, 1682, 1605, 1357, 1267, 956, 828. 1H NMR (300 MHz,
CDCl ): δ ϭ 1.5Ϫ1.8 (m, 3 H), 2.0Ϫ2.1 (m, 3 H), 2.6 (s, 3 H),
.45Ϫ3.5 (m, 1 H), 5.7 (dd, J ϭ 10.2, 2.1 Hz, 1 H), 5.9Ϫ6.0 (m, 1
2
[
Such a dimer has already been observed in the phenoxycarbon-
ylation of allylic carbonates: C. Goux, P. Lhoste, D. Sinou, A.
Masdeu, J. Organometallic Chem. 1996, 511, 139Ϫ143.
[9]
3
3
1
3
H), 7.3 (d, J ϭ 8.3 Hz, 2 H), 7.9 (d, J ϭ 8.3 Hz, 2 H) ppm.
NMR (CDCl , 75 MHz): δ ϭ 21.1, 25.0, 26.7, 32.4, 42.0, 128.0,
C
2 2
One possible mechanistic hypothesis is that [PdCl (TFP) ] acts
0
3
as a precatalyst to generate Pd in situ. This can displace the
ϩ
128.6, 129.1, 129.2, 135.3, 152.2, 198.0. CI-HRMS (for [MH ])
acetate leaving group to form a π-allyl complex intermediate
[2]
calcd. for C14
H16O: 201.12794; found 201.12777.
(see ref. ). Fluoride ion activates the aromatic moiety of the
[6]
boronic acid partner towards transmetallation (ref. ) which is
followed by reductive elimination at the less hindered site of
the π-allyl complex, yielding the coupling product regio- and
stereoselectively. An interesting evidence that the attack at the
π-allyl complex occurs from the same face of palladium has
1,3-Diphenyl-1-heptene (3m): Colorless liquid (147 mg, 59%). (pet-
Ϫ1
roleum ether). IR (NaCl): ν˜ ϭ 3024 cm , 2927, 1646, 1599, 1493,
1
1
682, 1605, 1451, 1465, 1377, 962, 743, 698. H NMR (300 MHz,
CDCl ): δ ϭ 1.0 (t, J ϭ 7.0 Hz, 3 H), 1.30Ϫ1.45 (m, 4 H), 1.9Ϫ1.95
m, 2 H), 3.50Ϫ3.55 (m, 1 H), 6.40Ϫ6.55 (m, 2 H), 7.25Ϫ7.45 (m,
3
[
3c]
been provided on chiral cyclic acetates by Hayashi (ref. ).
Methanol is known to displace allylic acetates under palladium
catalysis: Y. Hamada, N. Seto, Y. Takayanagi, T. Nakano, O.
Hara, Tetrahedron Lett. 1999, 40, 7791Ϫ7794.
[11] [11a]
(
[10]
0 H) ppm. 13C NMR (CDCl
1
4
3
, 75 MHz): δ ϭ 14.5, 23.2, 30.3, 36.1,
9.7, 126.6, 126.65, 127.5, 128.1, 128.9, 129.7, 135.0, 138.1, 145.2.
ϩ
CI-HRMS (for [MH ]) calcd. for C19
51.17995.
H22: 251.17997; found
R. J. Bushby, G. J. Ferber, J. Chem. Soc., Perkin Trans. 2
2
[11b]
1
976, 1683Ϫ1688.
M. Mahindaratne, K. Wimalasena, J.
[11c]
Org. Chem. 1998, 63, 2858Ϫ2866.
S. Zhang, D. Marshall,
L. Liebeskind, J. Org. Chem. 1999, 64, 2796Ϫ2804. [
11d]
A. M.
Acknowledgments
The authors wish to thank Dr. Jean-Pierre Vors from Aventis Crop-
science Lyon for his interest in this work.
Echavarren, J. K. Stille, J. Am. Chem. Soc. 1987, 109,
5
478Ϫ5486. [
Chem. 1993, 58, 7688Ϫ7693.
J. Org. Chem. 1999, 64, 1684Ϫ1688.
11e]
P. H. Espeel, B. Janssens, P. A. Jacobs, J. Org.
[11f]
M. E. Mowery, P. De Shong,
Received January 18, 2002
[O02025]
[
1] [1a]
A. Suzuki, T. Yanagi, N. Miyaura, Synth. Commun. 1981,
2448
Eur. J. Org. Chem. 2002, 2445Ϫ2448