Aminocarbonylation of (Hetero)aryl bromides with ammonia and amines using a palladium/dalphos catalyst system

Article abstract of DOI:10.1002/adsc.201200580

Variants of the DalPhos [2-aminophenylbisadamantyl)phosphine] ligand family were examined in a palladium-catalyzed carbonylative amination reaction using inexpensive carbon monoxide and ammonia as reagents. As a result of this survey, the Pyr-DalPhos ligand was identified as being effective for the selective aminocarbonylation of aryl bromides with ammonia, as well as primary and secondary alkylamines. A variety of primary aromatic, heteroaromatic and N-substituted benzamides were formed in moderate to good yields. As part of this study, a (Mor-DalPhos)Pd-benzoyl complex was prepared and crystallographically characterized, thereby showing the viability of the carbonyl insertion step. Copyright

Full text of DOI:10.1002/adsc.201200580

FULL PAPERS
DOI: 10.1002/adsc.201200580
Aminocarbonylation of (Hetero)aryl Bromides with Ammonia
and Amines using a Palladium/DalPhos Catalyst System
a
a,
b
Pamela G. Alsabeh, Mark Stradiotto, * Helfried Neumann,
b,
and Matthias Beller *
a
Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J3
Fax : (+1)-902-494-1310; e-mail: mark.stradiotto@dal.ca
Leibniz-Institut fꢀr Katalyse an der Universitꢁt Rostock e.V., Albert-Einstein-Str. 29a, 18059 Rostock, Germany
b
Fax : (+49)-381-1281-5000; e-mail: matthias.beller@catalysis.de
Received: July 3, 2012; Published online: November 4, 2012
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201200580.
Abstract:
aminophenylbis
Variants
of
the
DalPhos
[2- matic, heteroaromatic and N-substituted benzamides
ACHTUNGTRENNUNGa damantyl)phosphine] ligand family were formed in moderate to good yields. As part of
were examined in a palladium-catalyzed carbonyla- this study, a (Mor-DalPhos)Pd-benzoyl complex was
tive amination reaction using inexpensive carbon prepared and crystallographically characterized,
monoxide and ammonia as reagents. As a result of thereby showing the viability of the carbonyl inser-
this survey, the Pyr-DalPhos ligand was identified as tion step.
being effective for the selective aminocarbonylation
of aryl bromides with ammonia, as well as primary Keywords: amides; ammonia; carbonylation; N,P li-
and secondary alkylamines. A variety of primary aro- gands; palladium
[
6]
Introduction
ammonia at mild temperatures, the cross-coupling
[7]
of hydrazine
and the a-arylation of acetone
[
8]
Palladium-catalyzed cross-coupling reactions have (Figure 1).
become an indispensable tool for the synthesis of nat-
Palladium-catalyzed carbonylative couplings of aryl
ural products, pharmaceuticals and conjugated materi- and vinyl halides are gaining increasing interest
[1]
als. Among the most common and efficient of these among synthetic chemists as an important pathway
[9]
reactions is Buchwald–Hartwig amination, a powerful for the construction of carboxylic acid derivatives.
method for the formation of CÀN linkages from Recent contributions from Beller and co-workers in
amines and aryl halides. However, only recently this area include carbonylative Heck, Sonoga-
have these couplings and other transition metal-cata- couplings as well as amino-
lyzed processes been extended to the use of ammonia, carbonylations. Carbonylative amination reactions
[
1c,g,2]
[9a,10]
[
9a,11]
[9a,12]
A
H
U
G
E
N
N
shira
and Suzuki
[9a,13]
an inexpensive and readily available starting material had been restricted to primary and secondary amines
that is ideal for the synthesis of nitrogen-containing until some of us reported for the first time the use of
[3]
molecules. Although palladium-catalyzed ammonia ammonia gas, giving direct access to synthetically
monoarylation has proven challenging for the vast useful primary aromatic and heteroaromatic
[
14]
majority of established catalyst systems used for amides.
Buchwald–Hartwig amination, due to the propensity
for catalyst deactivation and/or uncontrolled polyary-
lation, new DalPhos ligands developed by the Stra-
diotto group have been found to circumvent these
and similar issues pertaining to the functionalization
The straightforward synthesis of primary
[
4]
of small molecules.
Successful lead variants of this new ligand family
include Me-DalPhos, for the cross-coupling of pri-
[
5]
mary and secondary amines as well as ammonia,
and Mor-DalPhos, for the selective monoarylation of (right) ligands used in Pd-catalyzed cross-coupling reactions.
Figure 1. Structures of Me-DalPhos (left) and Mor-DalPhos
Adv. Synth. Catal. 2012, 354, 3065 – 3070
ꢂ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
3065

Pamela G. Alsabeh et al.
FULL PAPERS
aromatic amides via amincarbonylation of (hetero)ar- (220.8 ppm) of the aromatic region in agreement with
yl bromides and chlorides using palladium catalyst a PdÀC(O)Ph interaction and in direct contrast with
systems was developed based on either cataCXiumA typical benzoyl groups found in organic frameworks
(
22 examples, GC yields 30–98%, 3 isolated yields 80– (i.e., benzamide 170 ppm, benzaldehyde 192 ppm,
9
1%) or DPPF (22 examples, GC yields 30–98%, 3 benzoic acid 172 ppm). Single crystal X-ray diffraction
[14]
isolated yields 85–90%).
An important feature of data obtained for crystals of 2·CH Cl support the so-
2 2
this reaction is the dual role of ammonia as both nu- lution NMR analyses; an ORTEP diagram of
cleophile and base. This protocol was later extended 2·CH Cl is shown in Figure 2.
2
2
to phenols through the in situ generation of aryl nona-
Encouraged by the facile formation of 2, we set out
[15]
flates.
While effective approaches using benzoic to screen a range of DalPhos ligands in the bench-
[
16]
acids or acid chlorides, as well as ammonia surro- mark aminocarbonylation of bromobenzene forming
[
17]
gates [NH
these latter approaches lack the atom economy asso- based on those that had previously proven effective
ciated with using ammonia and carbon monoxide di- for such transformations [i.e., Pd(OAc) , ligand, 1,4-
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
(TMS) , t-BuNH ] have been reported,
benzamide (Scheme 1). The choice of conditions was
2
2
AHCTUNGTRENNUNG
2
[18]
[14]
rectly.
dioxane, 1008C, 16 h].
Under the test conditions
Considering the utility of DalPhos ligands in chal- (2 mol% Pd, 6 mol% ligand, 2 bar CO, 2 bar NH ),
3
[
5,6]
lenging ammonia arylations,
and the recent estab- we were surprised to see that most catalysts featuring
lishment of aminocarbonylation protocols employing
[
14]
gaseous ammonia and carbon monoxide,
we
became interested in evaluating the capabilities of
DalPhos ligands in palladium-catalyzed aminocarbo-
nylation. Herein, we describe our results on carbony-
lative amination reactions of (hetero)aryl bromides
featuring ammonia and other amine coupling part-
ners, utilizing a Pd/DalPhos catalyst system.
Results and Discussion
Our interest in palladium-catalyzed carbonylative
amination reactions was initiated upon observation
2
that [(k -Mor-DalPhos)Pd(Ph)Cl] (1) was cleanly
2
transformed into {(k -Mor-DalPhos)Pd[C(O)Ph]Cl}
(
2) upon exposure to an atmosphere of CO [Eq. (1)].
This transformation establishes the validity of carbon-
yl insertion involving the putative oxidative addition
catalytic intermediate 1, and related DalPhos deriva-
tives.
Complex 2·0.5(CH Cl ) was successfully isolated as
2
2
an analytically pure solid in quantitative yield. Solu-
tion NMR characterization data agree with the pro-
posed structure of 2 as being a square planar complex
containing a benzoyl group.
Figure 2. ORTEP diagram of 2·CH Cl shown with 50% dis-
placement ellipsoids. All hydrogen atoms and the dichloro-
methane solvate have been omitted for clarity. Selected in-
2
2
teratomic distances (ꢃ): Pd P, 2.2630(7); Pd N, 2.233(2);
À
À
13
Notably, the C NMR resonance of the carbonyl PdÀCl, 2.3796(7); PÀC , 1.846(3); NÀC , 1.464(3); PdÀ
aryl
aryl
group
appears
significantly
more
downfield C(O)C , 2.055(3); PdC(O)ÀC , 1.553(4).
Ph
Ph
3066
asc.wiley-vch.de
ꢂ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2012, 354, 3065 – 3070

Aminocarbonylation of (Hetero)aryl Bromides with Ammonia and Amines
tive L2 afforded only poor conversions with no prod-
uct, while Me-DalPhos (L3), benzyl (L5) and pyrrole
L6) variants gave both little conversion and product.
Interestingly, the diphenylphosphino-substituted
(
ligand L7 was more effective than Mor-DalPhos
under these test conditions, affording modest conver-
sion and yield. On the basis of the results obtained
with L4, optimization was continued with this ligand
in an effort to achieve full conversion (Table 1).
The use of increased pressures of CO and NH was
3
first examined in an attempt to push the reaction to-
wards full consumption of bromobenzene. However,
this change in pressure was not beneficial for the L4
catalyst system (Table 1, entry 1). At a higher temper-
ature (1208C), conversion was greatly improved, af-
fording a significant increase in yield (Table 1,
entry 2). A modest decrease in the conversion was ob-
served when less ligand was used (Table 1, entry 3),
although the yield did not suffer (68 vs. 62%). When
the Pd loading was doubled (4 mol%), near complete
conversion was obtained; however, similar results
Scheme 1. Ligand screening for the palladium-catalyzed
aminocarbonylation of bromobenzene. General conditions:
bromobenzene (1 mmol), PdACHTGNUTERNUNNG
(OAc) (0.02 mmol), ligand were obtained when using standard loading (2 mol%)
2
(
1
0.06 mmol), CO (2 bar), NH (2 bar), 1,4-dioxane (2 mL), and 1M concentration of bromobenzene in 1,4-diox-
3
008C, 16 h; Ad =adamantyl. Conversion and yield (indicat- ane (Table 1, entries 4 and 5). Continuing at the
ed in parentheses) determined by GC based on bromoben-
zene using hexadecane as an internal standard.
higher concentration, good conversion but only mod-
erate yield resulted when using a decreased Pd:L
ratio (Table 1, entry 6), while an increase to 3 mol%
Pd gave access to the best yields (Table 1, entries 7
phenylene P,N ligands achieved little to no conversion and 8). Thus, isolated yields (72 vs. 79%) determined
of the starting material and/or poor yield of benz- the optimal Pd:L ratio (1:3).
A
C
H
T
U
N
G
T
R
E
N
N
U
N
G
amide. Among the ligands surveyed, the pyridine-de-
Once Pd/L4 catalyst mixtures had been identified
rived ligand L4 (Pyr-DalPhos) proved most effective, as being effective for the standard aminocarbonyla-
affording nearly 50% conversion and a promising tion of bromobenzene, we then proceeded to survey
yield. Although they both perform well in ammonia the scope of reactivity with CO and NH (Table 2). It
3
[6]
arylation, Mor-DalPhos (L1) and the related deriva- is worth mentioning that in order to fully establish
[a]
Table 1. Optimization of reaction conditions: variation of pressure, temperature, palladium loading and concentration.
[b]
[c]
Entry
Variations from the initial conditions
Conv. [%]
Yield [%]
1
2
Increase pressure to 10 bar CO, 4 bar NH3
1208C instead of 1008C
Pd:L=1:2
7
5
62
68
87
85
78
98
99
93
97
97
[
[
[
[
[
[
c]
3
4
5
6
7
8
c]
4 mol% Pd, 12 mol% L
c]
A
H
U
G
R
N
U
G
83
61
>99 (72)
>99 (79)
c]
Pd:L=1:2, 1M
3 mol% Pd, 6 mol% L
3 mol% Pd, 9 mol% L
c,d]
c,d]
[
a]
Initial reaction conditions: bromobenzene (1 mmol), Pd
,4-dioxane (2 mL), 1008C, 16 h.
Conversion and yield were determined by GC based on bromobenzene using hexadecane as an internal standard.
208C.
PhBr]=1M (isolated yield in parentheses).
ACHTUNGTNERNU(GN OAc) (0.02 mmol), L4 (0.06 mmol), CO (2 bar), NH (2 bar),
2
3
1
[
[
[
b]
c]
d]
1
[
Adv. Synth. Catal. 2012, 354, 3065 – 3070
ꢂ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
3067

Pamela G. Alsabeh et al.
FULL PAPERS
Table 2. Palladium-catalyzed aminocarbonylation of aryl naphthalene resulted in poor yield, 2-bromo-N-meth-
[a]
bromides.
ylaniline afforded only low conversion and 2-bromo-
mesitylene did not form any desired product under
these reaction conditions. Furthermore, aryl chlorides
proved to be unreactive substrates using either the
optimized conditions or with increased temperature
and time (i.e., 1408C/20 h). When compared to the
previously published reports of such aminocarbonyla-
tions using either Pd/cataCXiumA or Pd/DPPF cata-
[b]
Entry
Product
Yield [%]
[
14]
lysts, this current system provides similar efficiency
for those substrates previously reported (Table 2, en-
tries 1–6, 9 and 10). New examples applied herein to
this aminocarbonylation method include heterocyclic
aryl amides obtained in high isolated yields (Table 2,
entries 8 and 11), a potentially competitive aniline de-
rivative (Table 2, entry 7) and also N-alkyl (di)substi-
tuted amides (Scheme 2).
Having screened a variety of aryl bromides, we
then turned our attention to the use of different
amines, in place of ammonia, to form N-substituted
amides using the Pd/L4 catalyst system. Electron-rich
amines were successfully coupled to afford both sec-
ondary and tertiary amides. The secondary amines
1
2
3
4
5
6
R=H
79
89
70
96
76
40
56
R=4-Me
R=2-Me
R=4-OMe
R=4-CF3
R=4-CN
R=4-NHMe
[
c]
7
8
84
76
9
required
N,N,N,N-tetramethylethylenediamine
(
TMEDA) as the base in order to achieve good con-
versions for these reactions.
1
1
0
1
59
76
For the primary amines, n-butyl and 1-adamantyl
groups gave moderate yields of the corresponding
amides, where the amines acted as both nucleophile
[
a]
General reaction conditions: aryl bromide (1 mmol),
Pd(OAc) (0.03 mmol), L4 (0.09 mmol), CO (2 bar), NH
(2 bar), 1,4-dioxane (1 mL), 1208C, 16 h.
b]
ACHTUNGTRENNUNG
2
3
[
[
Isolated yield.
c]
Heated at 1408C.
the practical synthetic utility of this process, isolated
yields were obtained for all examples. We were
pleased to find that the reaction was tolerant of acti-
vated and deactivated bromoarenes, ortho-substitu-
tion as well as some heterocycles. Electron-donating
substituents such as Me and OMe (Table 2, entries 2
and 4) gave the best yields (89 and 96%, respective-
ly), while electron-deficient ring systems were also
coupled successfully (Table 2, entries 5 and 6). Nitro-
gen-containing heterocycles 6-quinoline (Table 2,
entry 8) and 3-pyridine (Table 2, entry 9) worked well
in the reaction, as did 2- and 3-substituted thiophene
derivatives (Table 2, entries 10 and 11). Notably, an
NH-containing substrate (Table 2, entry 7) was ac-
commodated under the reaction conditions, displaying
the chemoselective capabilities of the reaction.
Scheme 2. Palladium-catalyzed aminocarbonylation of bro-
mobenzene with alkylamines. Reaction conditions: bromo-
benzene (1 mmol), amine (2 mmol if solid or 0.4–0.9 mL if
Other sterically congested bromide substrates were
not as well-tolerated in aminocarbonylation as was 2- 1,4-dioxane (0.6–1 mL), 1208C, 16 h; isolated yields provid-
liquid), Pd ACHTGNUTERNN(UNG OAc) (0.03 mmol), L4 (0.09 mmol), CO (2 bar),
2
bromotoluene (Table 2, entry 3; 70% yield). 1-Bromo- ed.
3068
asc.wiley-vch.de
ꢂ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2012, 354, 3065 – 3070

Aminocarbonylation of (Hetero)aryl Bromides with Ammonia and Amines
and base. It should be noted that this lower reactivity times, followed by addition of NH
(2 bar) and CO (2 bar)
3
at room temperature. The autoclave was heated at 1208C
for 16 h, at which point the autoclave was cooled and the
pressure slowly released at room temperature. All reaction
vials were removed from the autoclave, the contents of each
were filtered over Celite, the filter was washed with a suffi-
cient amount of EtOAc and CH Cl (10–20 mL of each) and
of the primary and secondary amines compared to
ammonia provides the basis to perform selective
monoarylation reactions.
2
2
Conclusions
the resulting filtrate concentrated to dryness on silica
powder. The crude material was then purified by column
In summary, a palladium catalyst system featuring the chromatography (heptane/ethyl acetate) to afford the de-
ligand L4 (Pyr-DalPhos) was successfully employed sired aryl amide as a solid.
for the aminocarbonylation of (hetero)aryl bromides
with ammonia, as well as primary and secondary alkyl Preparation of Benzamide
amines as reactive partners. It is important to note
Bromobenzene was used as the aryl bromide and the crude
the dual role of ammonia in these reactions as both
material was purified with 0–50% ethyl acetate/heptane to
a nucleophile and base. In view of the successful re-
afford the desired product as an off-white solid; yield:
1
sults shown here and the promising conversions ob-
tained with other ligands in the initial ligand screen, (br s, 1H), 7.89–7.85 (m, 2H), 7.55–7.41 (m, 3H), 7.37 (br s,
we will continue to investigate related catalyst sys- 1H); C{ H} NMR (DMSO-d ): d=168.0 (C=O), 134.3
tems for this and other carbonylative cross-coupling (Cquat), 131.3, 128.3, 127.5, in agreement with that previously
9
5.5 mg (0.788 mmol, 79%). H NMR (DMSO-d ): d=7.98
6
1
3
1
6
[14a]
reported in the literature.
processes.
Experimental Section
Acknowledgements
General Information
We thank the State of Mecklenburg-Vorpommern and the
Bundesministerium fꢀr Bildung und Forschung (BMBF) for
financial support. We also thank Dr. W. Baumann, Dr. C.
Fischer and S. Buchholz (LIKAT) for analytical support.
P.G.A and M.S. also thank the NSERC of Canada (including
a Discovery Grant for M.S. and a Postgraduate Scholarship
for P.G.A), the Killam Trusts, and Dalhousie University for
their generous support of this work.
Unless otherwise stated, all reactions were set up using stan-
dard Schlenk techniques under argon. Chemicals were pur-
chased from Fluka, Aldrich, Alfa Aesar and Strem and used
as received. 1,4-Dioxane was distilled over CaH and stored
2
under
argon,
N,N,N’,N’-tetramethylethylenediamine
(
TMEDA) was distilled/stored under air, and n-butylamine
and morpholine were distilled/stored under argon. Gas chro-
matography was performed on a Hewlett Packard HP
1
6
890N chromatograph with an HP5 column.
H and
1
3
References
C NMR characterization data were collected at 300 K on
Bruker AV-300 and AV-400 spectrometers operating at
00.1 and 75.5 MHz or 400.1 and 100.6 MHz (respectively)
[
1] For some recent reviews and relevant book sections
3
see: a) R. J. Lundgren, M. Stradiotto, Chem. Eur. J.
and with chemical shifts reported in parts per million down-
field relative to the internal standard solvent peak. Mass
spectra were in general recorded on an AMD 402/3 or an
HP 5989A mass selective detector. CCDC 877542 contains
the supplementary crystallographic data for this paper (for
2
012, 18, 9758–9769; b) J. Magano, J. R. Dunetz, Chem.
Rev. 2011, 111, 2177–2250; c) J. F. Hartwig, Organotran-
sition Metal Chemistry, University Science Books, Sau-
salito, California, 2010, pp 877–966; d) L. F. Tietze, A.
Duefert, Pure Appl. Chem. 2010, 82, 1375–1392; e) S.
Brꢁse, A. de Meijere, in: Metal-Catalyzed Cross-Cou-
pling Reactions, (Eds.: A. de Meijere, F. Diederich),
Wiley-VCH, Weinheim, 2008, pp 217–315; f) N.
Miyaura, in: Metal-Catalyzed Cross-Coupling Reac-
tions, (Eds.: A. de Meijere, F. Diederich), Wiley-VCH,
Weinheim, 2008, pp 41–123; g) L. Jiang, S. L. Buch-
wald, in: Metal-Catalyzed Cross-Coupling Reactions,
(Eds.: A. de Meijere, F. Diederich), Wiley-VCH, Wein-
heim, 2008, pp 699–760; h) K. C. Nicolaou, P. G.
Bulger, D. Sarlah, Angew. Chem. 2005, 117, 4516–4563;
K. C. Nicolaou, P. G. Bulger, D. Sarlah, Angew. Chem.
2005, 117, 4516–4563; Angew. Chem. Int. Ed. 2005, 44,
4442–4489.
2
·CH Cl ). These data can be obtained free of charge from
2 2
The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
General Procedure
To six 4-mL glass vials were added Pd
.7 mg), Pyr-DalPhos (L4; 9 mol%, 41.0 mg), aryl bromide
1.00 mmol, if solid) and a magnetic stir bar. All vials were
ACHTUNGTNERNGNU( OAc) (3 mol%,
2
6
(
placed in a metal alloy plate, sealed with a cap containing
a Teflon-rubber faced septum and an inlet needle, and then
the vials were evacuated/backfilled with argon three times.
1,4-Dioxane (1.00 mL) and aryl bromide (1.00 mmol, if
liquid) were injected into each vial, stirred briefly and the
alloy plate with vials was transferred into a 300-mL auto-
clave (Parr Instruments 4560 series) under an atmosphere of
argon. The autoclave was then flushed with NH3 three
[2] a) D. S. Surry, S. L. Buchwald, Chem. Sci. 2011, 2, 27–
50; b) B. Schlummer, U. Scholz, in: Modern Arylation
Methods, (Ed.: L. Ackermann), Wiley-VCH Verlag,
Weinheim, 2009, pp 69–120; c) J. F. Hartwig, Acc.
Adv. Synth. Catal. 2012, 354, 3065 – 3070
ꢂ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
3069

Pamela G. Alsabeh et al.
FULL PAPERS
Chem. Res. 2008, 41, 1534–1544; d) D. S. Surry, S. L.
Buchwald, Angew. Chem. 2008, 120, 6438–6461; D. S.
Surry, S. L. Buchwald, Angew. Chem. 2008, 120, 6438–
[11] a) X.-F. Wu, H. Neumann, M. Beller, Angew. Chem.
2011, 123, 11338–11342; X.-F. Wu, H. Neumann, M.
Beller, Angew. Chem. 2011, 123, 11338–11342; Angew.
Chem. Int. Ed. 2011, 50, 11142–11146; b) X.-F. Wu, B.
Sundararaju, H. Neumann, P. H. Dixneuf, M. Beller,
Chem. Eur. J. 2011, 17, 106–110.
6
461; Angew. Chem. Int. Ed. 2008, 47, 6338–6361.
[
3] For reviews on the use of ammonia in transition-metal
catalysis see: a) J. L. Klinkenberg, J. F. Hartwig, Angew.
Chem. 2011, 123, 88–98; J. L. Klinkenberg, J. F. Hart-
wig, Angew. Chem. 2011, 123, 88–98; Angew. Chem.
Int. Ed. 2011, 50, 86–95; b) J. I. van der Vlugt, Chem.
Soc. Rev. 2010, 39, 2302–2322; c) Y. Aubin, C. Fisch-
meister, C. M. Thomas, J.-L. Renaud, Chem. Soc. Rev.
[
12] X.-F. Wu, H. Neumann, M. Beller, Adv. Synth. Catal.
2
011, 353, 788–792.
[
13] a) X.-F. Wu, J. Schranck, H. Neumann, M. Beller,
ChemCatChem 2012, 4, 69–71; b) X.-F. Wu, J. Schranck,
H. Neumann, M. Beller, Tetrahedron Lett. 2011, 52,
3
702–3704.
14] a) X.-F. Wu, H. Neumann, M. Beller, Chem. Eur. J.
010, 16, 9750–9753; b) X.-F. Wu, H. Neumann, M.
2
010, 39, 4130–4145.
[
[
4] For a review on the use of DalPhos ligands in transition
metal-catalyzed reactions see: R. J. Lundgren, K. D.
Hesp, M. Stradiotto, Synlett 2011, 2443–2458.
2
Beller, Chem. Asian J. 2010, 5, 2168–2172.
15] X.-F. Wu, H. Neumann, M. Beller, Chem. Eur. J. 2012,
[
[
[
5] R. J. Lundgren, A. Sappong-Kumankumah, M. Stra-
1
8, 419–422.
16] a) C. L. Allen, J. M. J. Williams, Chem. Soc. Rev. 2011,
0, 3405–3415; b) T. Zweifel, J.-V. Naubron, H. Grꢀtz-
diotto, Chem. Eur. J. 2010, 16, 1983–1991.
[
6] R. J. Lundgren, B. D. Peters, P. G. Alsabeh, M. Stradiot-
to, Angew. Chem. 2010, 122, 4165–4168; R. J. Lundgren,
B. D. Peters, P. G. Alsabeh, M. Stradiotto, Angew.
Chem. 2010, 122, 4165–4168; Angew. Chem. Int. Ed.
4
macher, Angew. Chem. 2009, 121, 567–571; T. Zweifel,
J.-V. Naubron, H. Grꢀtzmacher, Angew. Chem. 2009,
1
21, 567–571; Angew. Chem. Int. Ed. 2009, 48, 559–563;
c) J. W. Kim, K. Yamaguchi, N. Mizuno, Angew. Chem.
008, 120, 9389–9391; J. W. Kim, K. Yamaguchi, N.
2
010, 49, 4071–4074.
7] R. J. Lundgren, M. Stradiotto, Angew. Chem. 2010, 122,
868–8872; R. J. Lundgren, M. Stradiotto, Angew.
Chem. 2010, 122, 8868–8872; Angew. Chem. Int. Ed.
010, 49, 8686–8690.
[
2
8
Mizuno, Angew. Chem. 2008, 120, 9389–9391; Angew.
Chem. Int. Ed. 2008, 47, 9249–9251; d) H. Fujiwara, Y.
Ogasawara, M. Kotani, K. Yamaguchi, N. Mizuno,
Chem. Asian J. 2008, 3, 1715–1721; e) H. Fujiwara, Y.
Ogasawara, K. Yamaguchi, N. Mizuno, Angew. Chem.
2
[
[
8] K. D. Hesp, R. J. Lundgren, M. Stradiotto, J. Am.
Chem. Soc. 2011, 133, 5194–5197.
9] For recent reviews see: a) X.-F. Wu, H. Neumann, M.
Beller, Chem. Soc. Rev. 2011, 40, 4986–5009; b) A.
Brennfꢀhrer, H. Neumann, M. Beller, Angew. Chem.
2
007, 119, 5294–5297; H. Fujiwara, Y. Ogasawara, K.
Yamaguchi, N. Mizuno, Angew. Chem. 2007, 119, 5294–
297; Angew. Chem. Int. Ed. 2007, 46, 5202–5205.
5
2
009, 121, 4176–4196; A. Brennfꢀhrer, H. Neumann,
[
17] a) E. Takꢄcs, C. Varga, R. Skoda-Fçldes, L. Kollꢄr, Tet-
rahedron Lett. 2007, 48, 2453–2456; b) E. Morera, G.
Ortar, Tetrahedron Lett. 1998, 39, 2835–2838.
M. Beller, Angew. Chem. 2009, 121, 4176–4196; Angew.
Chem. Int. Ed. 2009, 48, 4114–4133; c) C. F. J. Barnard,
Organometallics 2008, 27, 5402–5422.
[18] For a recent report on the use of in situ generated am-
monia and CO for the Pd-catalyzed synthesis of aryl
amides see: D. U. Nielsen, R. H. Taaning, A. T. Lind-
hardt, T. M. Gøgsig, T. Skrydstrup, Org. Lett. 2011, 13,
4454–4457.
[
10] a) J. Schranck, X.-F. Wu, H. Neumann, M. Beller,
Chem. Eur. J. 2012, 18, 4827–4831; b) X.-F. Wu, H.
Jiao, H. Neumann, M. Beller, ChemCatChem 2011, 3,
7
26–733.
3070
asc.wiley-vch.de
ꢂ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2012, 354, 3065 – 3070