Easily Prepared Mono(N,N-dialkylamino)phosphine Palladium(II) Complexes: Structural and Catalytic Evaluation

Article abstract of DOI:10.1002/ejic.202100232

The search for efficient, active and universal catalyst systems for transition-metal catalyzed cross-coupling reactions, continues to be of interest to researchers world-wide. Herein, we report two new Pd(II) complexes, effortlessly prepared from N,N-dialkylamino-phosphines for Suzuki-Miyaura cross-coupling reactions. These sufficiently hindered (% V_Bur=30.0–31.5 %) and electron rich (v_CO=1947.41–1946.29 cm^?1) aminophosphines formed active catalysts for Suzuki-Miyaura coupling of aryl bromides and chlorides.

Full text of DOI:10.1002/ejic.202100232

European Journal of Inorganic Chemistry
Accepted Article
Title: Easily prepared mono(N,N-dialkylamino)phosphine palladium(II)
complexes: Structural and catalytic evaluation
Authors: Jairus L. Lamola, Joy C. Shilubana, Lonwabo Ngodwana,
Banele Vatsha, Adedapo S. Adeyinka, Munaka C. Maumela,
Cedric H. Holzapfel, and Edwin Mpho Mmutlane
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To be cited as: Eur. J. Inorg. Chem. 10.1002/ejic.202100232
Link to VoR: https://doi.org/10.1002/ejic.202100232
01/2020

10.1002/ejic.202100232
European Journal of Inorganic Chemistry
COMMUNICATION
Easily prepared mono(N,N-dialkylamino)phosphine palladium(II)
complexes: Structural and catalytic evaluation
Jairus L. Lamola,[a] Joy C. Shilubana,[a] Lonwabo Ngodwana,[a] Banele Vatsha,[a] Adedapo S.
Adeyinka,[a] Munaka C. Maumela,[a,b] Cedric W. Holzapfel,[a] and Edwin M. Mmutlane*[a]
[a]
*
Jairus L. Lamola, Joy C. Shilubana, Dr. Lonwabo Ngodwana, Dr. Banele Vatsha, Dr. Adedapo S. Adeyinka, Prof. Dr. Cedric W. Holzapfel,
Dr. Edwin M. Mmutlane
Research Centre for Synthesis and Catalysis
Department of Chemical Sciences
University of Johannesburg, Kingsway Campus
P.O. Box 123, Auckland Park, 2006, South Africa
E-mail: edwinm@uj.ac.za
[b]
Prof. Dr. Munaka C. Maumela
Sasol (Pty) Ltd, Research & Technology (R & T), 1 Klasie Havenga Rd
Sasolburg 1947, South Africa.
Supporting information (SI) for this article is given via a link at the end of the document.
Abstract: The search for efficient, active and universal catalyst
systems for transition-metal catalyzed cross-coupling reactions,
continues to be of interest to researchers world-wide. Herein, we
report two new Pd(II) complexes, effortlessly prepared from N,N-
carbazolyl phosphines which showed a decrease in donor
character with increase in number of N-carbazolyl substituents in
the order [PPh2(NC12H8)] < [PPh(NC12H8)2] < [P(NC12H8)3] (Table
1). Furthermore, Singh and co-workers identified [PPh(NEt2)2)] as
dialkylamino-phosphines for Suzuki-Miyaura cross-coupling reactions. a poor donor than [PPh2(NEt2)], with electron descriptors of vCO
=
1
These sufficiently hindered (% VBur = 30.0 – 31.5%) and electron rich
(vCO = 1947.41 - 1946.29 cm-1) aminophosphines formed active
catalysts for Suzuki-Miyaura coupling of aryl bromides and chlorides.
2007 cm-1 and 1974 cm-1, and JPSe = 761 Hz and 746 Hz,
respectively.[29]
Table 1. Electronic descriptors derived from vCO of trans-[RhCl(CO)L2],
complexes.
Palladium-catalyzed cross-coupling reactions are indispensable
tools in synthesis, providing easy access to C-C and C-X (X = N,
O, S, F, Si, and B) bonds.[1,2] Among them is the Suzuki-Miyaura
reaction, widely used in pharmaceuticals[3], agrochemicals[4],
natural products[5], materials science[6] and process chemistry[7].
As the application of this versatile reaction broadens, the need for
robust, highly active catalyst systems increases. Pioneering
contributions in this regard have been trialkyl-, biaryl-, ferrocenyl-
and adamantyl-based phosphines developed by Fu[8], Buchwald[9],
Hartwig[10] and Beller[11], respectively. Notable contributions have
Entry
1
Ligand
vCO (cm-1)
2016
2012
2012
2009
2000
1997
1990
1965
1951
1949
1947
1946
Ref
[34]
a
P(OPh)3
a
2
P(Pyrrolyl)3
[31]
b
3
P(Carbazolyl)3
[33]
a
4
PhP(Pyrrolyl)2
[31]
5
Ph2P(Pyrrolyl)a
[31]
subsequently been made by Kwong[12], Verkade[13], Reetz[14]
Stradiotto[15], Hong[16], and many more.
,
b
6
PPh(Carbazolyl)2
[33]
Our focus is on aminophosphines,[17,18] pioneered as ligands
in Suzuki-Miyaura coupling by Woolins[19] and now applicable in
other catalyst systems such as intermolecular hydroamination of
alkenes[20], alkylation of amines by alcohols[21], and amination of
aryl-substituted allylic alcohols[22]. This class of ligands allows for
easy tuning of donor and steric capacities by varying substituents
on the N-(abundance of amines, including easily accessible
imidazol-2-ylidene- and pyridinylide amines), the P-center or
both.[23–29] Arylamino groups attenuate the basicity of the P-donor
atom through resonance and σ-electron withdrawal, while
aliphatic amino groups increase the basicity due to the absence
of the π-system.[30] This was idependently demonstrated by
Ziółkowski[31] and Woollins[32], studying the electronic properties
of N-pyrrolyl- and N-pyrrolidinyl-phosphines employing vCO of
trans-[RhCl(CO)L2], respectively. Their studies also revealed the
alkyl-based [P(NC4H8)3] (1951 cm-1) as a better donor compared
to its aromatic counterpart [P(NC4H4)3] (2012 cm-1) (Table 1,
entries 9 and 2). Most notable was the finding that P-basicity
increases with decrease of amino-substituents, Ph2P(NR2) >
PhP(NR2)2 > P(NR2)3. This trend was further confirmed by
Burrows and co-workers[33], in their parameterization studies of N-
7
PPh2(Carbazolyl)b
[33]
a
8
PPh3
[34]
a
9
P(Pyrrolidinyl)3
[32]
a
10
11
12
PhP(Pyrrolidinyl)2
[32]
Ph2P(di-n-butylamino)c
Ph2P(di-iso-butylamino)c
this work
this work
aKBr. bCH2Cl2. cWB97XD/LANL2DZ.
Following these precedents, we report the use of novel Pd(II)
complexes comprising strongly basic mono-(N,N-
dialkylamino)diphenylphosphines of general formular PPh2(NR2)
(Scheme 1), for Suzuki-Miyaura cross-coupling. Previously
demonstrated to be good donors, the catalytic efficiency of this
family of aminophosphine ligands was evaluated parallel to
triphenylphosphine (PPh3) and 2-dicyclohexylphosphino-2’,6’-
dimethoxybiphenyl (SPhos) as the benchmark and gold standard,
respectively.
1
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10.1002/ejic.202100232
European Journal of Inorganic Chemistry
COMMUNICATION
Diphenylphosphino-N,N-di-n-butylamine (L1) and diphenyl-
phosphino-N,N-di-isobutylamine (L2) were prepared by condensation
of chlorodiphenylphosphine with the corresponding secondary amine
in anhydrous diethyl ether or THF at room temperature (Scheme 1
(i)).[30]
(particularly L2), and full oxidation in 48 h. Additional stability tests
included base and elevated temperature exposure, to which they
were relatively stable (SI). Trace amounts of other phosphine
oxides were noticeable on the NMR spectra suggesting some
decomposition
or
possibly
the
oxide
of
1,1,2,2-
tetraphenyldiphosphine, the insidious homo-coupling product of
diphenylchlorophosphine[35–37] which would have escaped
recrystallization after the ligand synthesis. This we are currently
investigating further.
Scheme 1. Synthesis of mono-(N,N-dialkylamino)phosphine ligands through
condensation and complexation to Pd(II); (i) 1 equiv. NR2, 1 equiv. Et3N, and
0.5 equiv. PPh2Cl, rt, 3 h, N2, THF (L1, 88%) or Et2O (L2, 90%); (ii) 1 equiv.
(CH3CN)PdCl2, 2 equiv. L, rt, 24 h, N2, DCM, affording C1 (92%) and C2 (89%).
Table 3: Selected bond lengths and angles of complexes C1 and C2.a
Complex
Bond
Length
Bond
Angle
91.07(6)
88.23(6)
89.41(6)
91.25(6)
117.73(15)
93.92(2)
86.08(2)
86.08(2)
93.92(2)
113.83(8)
2.2774(15)
2.2989(16)
2.2907(15)
2.2737(15)
1.640(4)
The desired aminophosphine products were isolated in yields of
88% (L1, viscous oil) and 90% (L2, white powdery solid, after
recrytallization from absolute ethanol) in 3 h. The novel Pd(II)
complexes C1 and C2 were prepared through the reaction of the free
ligands with bis(acetonitrile)dichloropalladium(II) in CH2Cl2 for 24 h at
25 °C (Scheme 1 (ii) and Table 2). 31P NMR showed shifts 61.9 to
70.1 ppm (L1 → C1) and 64.3 – 68.7 ppm (L2 → C2).
C1
2.3084(7)
2.3084(7)
2.3533(6)
2.3533(6)
1.690(2)
C2
Table 2: Selected crystallographic and refinement parameters of C1 and C2.a
aThe complete list of bond lengths and angles can be retrieved in the SI. Both
complexes share similar bond lengths and angles around the Pd center, i.e.,
Pd-Cl (2.2774 and 2.3089 Å); Pd-P (2.2989 and 2.3533 Å); and Pd-P-N (113.09
and 113.83°), for C1 and C2, respectively. These are comparable to those
previously reported by Jin[38] (Pd-Cl = 2.2772 Å) and Jambor[39] (Pd-P = 2.3124
Å and P-N = 1.6901 Å).
Crystal
structure
Though not ideal substrates to model Suzuki-Miyaura
coupling, we could easily access 4-chlorobenzonitrile and
phenylboronic acid and used them to screen suitable reaction
conditions using C2 (Table 4). Optimal conditions were found to
be 3 mol % C2 and 3 equiv. of K3PO4 in toluene at 100 °C for 5 h,
affording the biaryl product in 82% yield (entry 10, Table 4). Yields
with K2CO3 (entries 1 – 4) and Cs2CO3 (entry 5) were poor
(Table 4). Similarly, the use of conventional solvents THF, DMF,
and CH2Cl2 gave poor yields (Table S3). With optimum conditions
determined[42–44], the catalytic efficacies of C1 and C2 were
compared using electronically
CCDC #
Complex
Empirical
formula
Formula
weight
Temperat
ure/K
2064686
2064689
C1
C2
C40H56Cl2N2P2Pd
804.10
C40H56Cl2N2P2Pd
804.10
[40]
[41]
100
100
Crystal
system
Space
group, Z
a/Å
Monoclinic
P21/c, 4
Triclinic
P-1, 1
Table 4: Optimization of Suzuki-Miyaura cross-coupling using C2.a
14.952(8)
9.929(5)
26.495(14)
90
8.9283(10)
8.9344(9)
b/Å
c/Å
13.2260(14)
109.168(2)
103.863(3)
90.467(3)
α/°
Entry
Solvent
Base
Catalyst
mol %
Temperature
(°C)
Time
(h)
GC
yield
(%)
9
β/°
103.283(14)
90
γ/°
Volume/Å
1
THF
K2CO3
K2CO3
K2CO3
K2CO3
Cs2CO3
K3PO4
K3PO4
K3PO4
K3PO4
K3PO4
K3PO4
1
1
1
1
1
1
2
3
3
3
3
reflux
reflux
140
100
100
100
100
100
100
100
100
24
24
24
24
24
24
24
24
12
5
3828(3)
963.16(18)
3
2
DCM
11
34
43
54
59
70
83
81
82
51
Final R
indexes
3
DMF
R1 = 0.0542, wR2 = 0.1361
R1 = 0.0365, wR2 = 0.1002
4
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
Toluene
[I>=2σ (I)]
5
aComplete crystal data can be retrieved from Table S1 and S2. Selected bond
lengths and angles are included in Table 3.
6
7
To get an indication of the robustness of the free ligands,
simple stability tests were conducted, where the rate of their
oxidation was monitored in isolated forms and solution (SI). 31P
NMR experiments revealed that in their isolated forms, L1 and L2
are stable to atmospheric air and moisture for the duration of the
study (6 days). Exposed to air and moisture whilst in solution, they
are only stable for 12 h, with increased oxidation over 24 h
8
9
10
11
1
aReaction conditions: ArCl, 1.2 equiv. PhB(OH)2, 3 equiv. base, 1 – 3 mol % C2,
solvent, 1 – 24 h, N2. GC yield (%) as an average of two experiments. Full
optimization table given in the SI.
2
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10.1002/ejic.202100232
European Journal of Inorganic Chemistry
COMMUNICATION
diverse aryl bromides and chlorides (entries 1 – 6. Table 5).
Catalytic efficacies of C1 and C2 were comparable in the parallel
screening of aryl bromides (entries 1 – 3, Table 5), with average
product yields of 76 and 78%, respectively. Differences were
observed in couplings of aryl chlorides (entries 4 – 6), with C2
marginally superior to C1, giving average yields of 74 and 68%,
respectively. The efficiency of C2 prompted its benchmarking
against SPhos and PPh3 (entry 7 – 14, Table 5). Prior to this, a
comparison between in-situ and pre-formed complexes of L2,
permitted the subsequent examination of L2 as a free ligand
(entries 6 – 7, Table 5). L2 and SPhos formed effective catalysts
for cross-coupling of activated aryl chlorides (7 – 11), with
average yields of 83 and 89%, respectively.
For deactivated chlorides (entries 12-14), SPhos gave
consistently high yields whilst yields with L2 were moderate. PPh3
gave no product at all, which is consistent with reports by Beller[11]
and Fu[8]. The superiority of SPhos, able to provide a catalyst
system that effects Suzuki-Miyaura coupling of even sterically
demanding aryl chlorides and boronic acids at room temperature
using 0.05-0.1% Pd, has been ascribed to the hemilabile methoxy
group(s) on a phenyl ring bearing these.[45] Besides the Buchwald
ligands,[9,43,46] other highly efficient catalyst systems for coupling
of deactivated aryl chlorides include those reported by Beller[11]
,
Fu[8] and Hartwig[10]. The group of Frech showed that palladium
nanoparticles are the catalytically active form when using
dichloro-bis(aminophosphine) complexes.[27] In our case, adding
excess elemental mercury at the beginning of the reaction (4-
chlorotoluene and phenylboronic acid) did not retard the reaction
at all; the same result as in Table 5, entry 5, was obtained,
indicative of the homogeneity of the reaction.
Table 5: Suzuki-Miyaura cross-coupling of aryl bromides and chlorides using
C1, C2, PPh3 and SPhos.a
A study to quantify the ligand electronic and steric
descriptors was also performed (Table 6). The carbonyl strecthing
frequencies (vCO) were accessed from computational models of
trans-RhCOCl(L)2. This study revealed the strong donor character
of the described P-N ligands compared to PPh3, due to the
strongly basic amine groups, as previously demonstrated by
Ziółkowski[31] and Woollins[32]. However, SPhos, comprising two
Cy groups, proved to be the best donor (Table 6).
Computational calculations of the overall electronic density
(ρ) donated by the P-ligands to the Rh-center further confirmed
the observed vCO (cm-1) trend (Table 6). Thus, the poor catalytic
performance of PPh3 based catalysts is ascribed to the overall
poor donor character of PPh3, in contrast to the more electron rich
SPhos and aminophosphines L1 and L2. The inherent role of
electron rich ligands towards facile oxidative addition is well
known.[43,47]
En
try
%: GC/
(isolated)
71 (68)
73 (69)
81 (79)
84 (81)
75 (70)
78 (73)
56 (51)
64 (60)
53 (50)
61 (58)
69 (65)
82 (79)
84 (80)
50
Ar1X
Ar2B(OH)2
PhB(OH)2
PhB(OH)2
Catalyst
C1
C2
1
2
3
4
5
6
4-MeOC6H4Br
4-CNC6H4Br
C6H5Br
C1
C2
C1
4-
MeC6H4B(OH)2
C2
C1
4-
C6H5Cl
MeC6H4B(OH)2
C2
C1
4-MeC6H4Cl
4-CNC6H4Cl
PhB(OH)2
PhB(OH)2
C2
C1
C2
L2/Pd
PPh3/Pd
SPhos/Pd
L2/Pd
PPh3/Pd
SPhos/Pd
L2/Pd
PPh3/Pd
SPhos/Pd
L2/Pd
PPh3/Pd
SPhos/Pd
L2/Pd
PPh3/Pd
SPhos/Pd
L2/Pd
PPh3/Pd
SPhos/Pd
L2/Pd
PPh3/Pd
SPhos/Pd
L2/Pd
PPh3/Pd
SPhos/Pd
7
8
4-CNC6H4Cl
4-CNC6H4Cl
4-CF3C6H4Cl
4-CF3C6H4Cl
4-NO2C6H4Cl
4-MeC6H4Cl
PhB(OH)2
Table 6: Parameterization of ligands.
90
b
Entry
Ligand
PPh3
L1
vCO (cm-1)a
1952.69c
1947.41
1946.29
1937.83
Electron density, ρ (a.u.)a
% VBur
29.2
30.0
31.5
32.7
86 (82)
56
1
2
3
4
0.0008
0.0012
0.0015
0.0030
4-
MeC6H4B(OH)2
91
L2
77 (71)
42
SPhos
aDetermined from WB97XD/LANL2DZ trans-RhCOCl(L)2 at DFT. bDetermined
from crystallographic data of PdCl2L2 (Table S1 and S4). cWith a 0.66%
deviation, which is within 0.05 and 3.71% deviation reported by Kohls and
Stein[48], at BP86/def2-TZVP and B3LYP/def2-TZVP, respevtively.
9
PhB(OH)2
89
79 (73)
44
2,5-
10
11
Me2C6H3B(OH)2
81
Steric effects, also important for efficient catalytic activity,
were quantified from the percent buried volume (% VBur) of
PdCl2L2 complexes (Table 6). Clavier and Nolan[49] found the %
VBur of SPhos and PPh3 to be 29.3- and 32.7%, and ours are
almost the same (29.2 and 32.7%, Table 6). Steric bulk is believed
to facilitate reductive elimination[43,47] which also explains the
catalytic outcomes of the more hindered L1, L2, and SPhos,
contrary to PPh3.
In conclusion, Pd(II) monoaminophosphine complexes
assembled from inexpensive and easily prepared air and moisture
stable ligands, formed promising catalyst systems for Suzuki-
Miyaura coupling of aryl bromides and chlorides. Through ligand
parameterization, we found sufficient steric bulk and electronic
density, vCO ≤ 1947.41 cm-1 and % VBur ≥ 30.0 % (L1 and L2), to
yield active catalysts for the described substrate scope. Whilst
88 (82)
71
PhB(OH)2
PhB(OH)2
PhB(OH)2
PhB(OH)2
95
80 (71)
0
12
b
90
59 (51)
0
13
b
1,2-
Me2C6H4Cl
79
69 (60)
0
14
b
4-MeOC6H4Cl
88
aReaction conditions: ArX, 1.2 equiv. ArB(OH)2, 3 equiv. K3PO4, 3 mol %
catalyst, Toluene, 5 h, N2. GC yield (%) as average of two experiments,
(isolated yields). bReaction ran for 24 h.
3
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10.1002/ejic.202100232
European Journal of Inorganic Chemistry
COMMUNICATION
SPhos and other literature reported ligands are, on the basis of
our small data set far superior, we are currently exploring the
utility of the aminophosphine ligands [PAr2(NR2, with R = alkyl or
aryl)] in terms of substrate scope and optimal catalyst loading and
reaction conditions in Suzuki-Miyaura and other cross coupling
reactions. The results will be disclosed in due course.
Soc. Dalton Trans. 2001, 2721–2723.
[20]
[21]
Z. Liu, J. F. Hartwig, J. Am. Chem. Soc. 2008, 23, 1–7.
L. M. Broomfield, Y. Wu, E. Martin, A. Shafir, Adv. Synth.
Catal. 2015, 357, 3538–3548.
[22]
[23]
R. Ghosh, A. Sarkar, J. Org. Chem. 2011, 76, 8508–8512.
P. Rotering, L. F. B. Wilm, J. A. Werra, F. Dielmann, Chem.
Eur. J. 2020, 26, 406–411.
Acknowledgements
[24]
[25]
M. A. Wünsche, P. Mehlmann, T. Witteler, F. Buß, P.
Rathmann, F. Dielmann, Angew. Chem. Int. Ed. 2015, 54,
11857–11860.
This work was funded through the NRF’s Thuthuka Program
(EMM, Grant no 107406: 2017-2019). Jairus Lamola is grateful
for a scholarship by SASOL. We thank Mr Mutsinyalo Nwamadi
(SPECTRUM) for assistance with NMR analyses. The authors
acknowledge the Centre for High Performance Computing
(CHPC), South Africa for providing computational resources to
this research project.
A. P. Mehlmann, C. Mück-lichtenfeld, T. Y. Tristan, F.
Dielmann, P. Mehlmann, C. Mück-lichtenfeld, T. T. Y. Tan,
F. Dielmann, Chem. Eur. J. 2016.
[26]
[27]
[28]
[29]
J. L. Bolliger, O. Blacque, C. M. Frech, Angew. Chem. Int.
Ed. 2007, 46, 6514–6517.
M. Oberholzer, C. M. Frech, Green Chem. 2013, 15, 1678–
1686.
Keywords: aminophosphines • biaryl • cross-coupling • ligand
parameters • Suzuki-Miyaura
J. Cheng, F. Wang, J. H. Xu, Y. Pan, Z. Zhang,
Tetrahedron Lett. 2003, 44, 7095–7098.
P. W. Dyer, J. Fawcett, M. J. Hanton, R. D. W. Kemmitt, R.
Padda, N. Singh, J. Chem. Soc., Dalton Trans. 2003, 104–
113.
[1]
T. J. Colacot, New Trends in Cross-Coupling Theory and
Applications., The Royal Society Of Chemistry, Cambridge,
2015.
[30]
[31]
[32]
[33]
[34]
[35]
[36]
[37]
J. Gopalakrishnan, Appl. Organomet. Chem. 2009, 23,
291–318.
[2]
A. Biffis, P. Centomo, A. Del Zotto, M. Zecca, Chem. Rev.
2018, 118, 2249–2295.
A. M. Trzeciak, T. Głowiak, J. J. Ziółkowski, J. Chem. Soc.,
Dalton. Trans. 1997, 1831–1837.
[3]
C. Torborg, M. Beller, Adv. Synth. Catal. 2009, 351, 3027–
3043.
M. L. Clarke, G. L. Holliday, A. M. Z. Slawin, J. D. Woollins,
J. Chem. Soc., Dalton Trans. 2002, 1093–1103.
A. D. Burrows, M. F. Mahon, M. Varrone, J. Chem. Soc.,
Dalton Trans. 2004, 3321–3330.
[4]
P. Devendar, R. Qu, W. Kang, B. He, G. Yang, J. Agric.
Food Chem. 2018, 66, 8914–8934.
[5]
A. Taheri Kal Koshvandi, M. M. Heravi, T. Momeni, Appl.
Organomet. Chem. 2018, 32, 1–59.
K. G. Moloy, J. L. Petersen, W. Virginia, W. V. Unigersity, J.
Am. Chem. Soc. 1995, 117, 7696–7710.
[6]
S. Xu, E. H. Kim, A. Wei, E. Negishi, Sci. Technol. Adv.
Mater. 2014, 15, 1–23.
L. Wu, V. T. Annibale, H. Jiao, A. Brookfield, D. Collison, I.
Manners, Nat. Commun. 2019, 10, 1–10.
Y. Sato, S. ichi Kawaguchi, A. Nomoto, A. Ogawa, Chem.
Eur. J. 2019, 25, 2295–2302.
[7]
B. J. Reizman, Y. M. Wang, S. L. Buchwald, K. F. Jensen,
React. Chem. Eng. 2016, 1, 658–666.
A. F. Littke, G. C. Fu, Angew. Chem. Int. Ed. 1999, 37,
3387–3388.
[8]
Y. Yamamoto, R. Tanaka, M. Ota, M. Nishimura, C. C.
Tran, S. I. Kawaguchi, S. Kodama, A. Nomoto, A. Ogawa,
J. Org. Chem. 2020, 85, 14708–14719.
[9]
D. W. Old, J. P. Wolfe, S. L. Buchwald, J. Am. Chem. Soc.
1998, 120, 9722–9723.
[10]
[11]
[12]
N. Kataoka, Q. Shelby, J. P. Stambuli, J. F. Hartwig, J. Org.
Chem. 2002, 8107, 5553–5566.
[38]
Y. Lai, Z. Zong, Y. Tang, W. Mo, N. Sun, B. Hu, Z. Shen, L.
Jin, W. H. Sun, X. Hu, Beilstein J. Org. Chem. 2017, 13,
213–221.
A. Zapf, A. Ehrentraut, M. Beller, Angew. Chem. Int. Ed.
2000, 39, 4153–4155.
[39]
[40]
[41]
[42]
[43]
[44]
[45]
[46]
J. Jansa, T. Řezníček, L. Dostál, Z. Růžičková, F. Bureš, R.
Jambor, Appl. Organomet. Chem. 2016, 30, 1036–1042.
S. Vuoti, J. Autio, M. Laitila, M. Haukka, J. Pursiainen, Eur.
J. Inorg. Chem. 2008, 1, 397–407.
K. H. Chung, C. M. So, S. M. Wong, C. H. Luk, Z. Zhou, C.
P. Lau, F. Y. Kwong, Chem. Commun. 2012, 48, 1967–
1969.
[13]
[14]
[15]
J. V Kingston, J. G. Verkade, J. Org. Chem. 2007, 72,
2816–2822.
R. Rabie, M. M. Hammouda, K. M. Elattar, Res. Chem.
Intermed. 2017, 43, 1979–2015.
G. D. Roiban, G. Mehler, M. T. Reetz, Eur. J. Org. Chem.
2014, 2070–2076.
S. Kotha, K. Lahiri, D. Kashinath, Tetrahedron 2002, 58,
9633–9695.
C. A. Wheaton, J. P. J. Bow, M. Stradiotto, Organometallics
2013, 32, 6148–6161.
R. Martin, S. L. Buchwald, Acc. Chem. Res. 2008, 41,
1461–1473.
[16]
[17]
Y. Chang, F. Hong, Tetrahedron 2013, 69, 2327–2335.
C. Kayan, N. Biricik, M. Aydemir, Transit. Met. Chem. 2011,
36, 513–520.
J. El-maiss, T. Mohy, E. Dine, C. Lu, I. Karam, A. Kanj, K.
Polychronopoulou, J. Shaya, Catalysts 2020, 10, 296.
K. L. Billingsley, K. W. Anderson, S. L. Buchwald, Angew.
Chem. Int. Ed. 2006, 45, 3484–3488.
[18]
[19]
M. Aydemir, A. Baysal, E. Sahin, B. Gumgum, S. Ozkar,
Inorganica Chim. Acta 2011, 378, 10–18.
M. L. Clarke, D. J. Cole-Hamilton, J. D. Woollins, J. Chem.
S. D. Walker, T. E. Barder, J. R. Martinelli, S. L. Buchwald,
4
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10.1002/ejic.202100232
European Journal of Inorganic Chemistry
COMMUNICATION
Angew. Chem. Int. Ed. 2004, 43, 1871–1876.
[47]
[48]
M. L. Clarke, J. J. R. Frew, Organomet. Chem. 2009, 44,
19–46, and references therein.
E. Kohls, M. Stein, Contrib. Sect. Nat. Math. Biotech. Sci.
2017, 38, 43–56.
[49]
H. Clavier, S. P. Nolan, Chem. Commun. 2010, 46, 841–
861.
…
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10.1002/ejic.202100232
European Journal of Inorganic Chemistry
COMMUNICATION
TOC
New mono-(N,N-dialkylamino)phosphine based palladium (II) complexes were successfully prepared and their crystal
structures determined. The complexes showed moderate to high catalytic performance in Suzuki-Miyaura cross-coupling of
aryl-bromides and chlorides which could be ascribed to their structural features.
6
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