Cobalt-catalyzed electrophilic amination of arylzincs with N-chloroamines

Article abstract of DOI:10.1002/chem.201300229

Roles reversed: An efficient cobalt-catalyzed electrophilic amination of arylzinc reagents has been achieved. A variety of functionalized arylzincs and N-chloroamines were coupled under mild conditions (see scheme). Both secondary and tertiary arylamines were obtained in moderate to excellent yields. Copyright

Full text of DOI:10.1002/chem.201300229

COMMUNICATION
DOI: 10.1002/chem.201300229
Cobalt-Catalyzed Electrophilic Amination of Arylzincs with N-Chloroamines
Xin Qian, Zailu Yu, Audrey Auffrant, and Corinne Gosmini*[a]
À
À
Aromatic C N bond-forming reactions are important for
tion of C N bonds through an electrophilic pathway. We al-
the synthesis of biologically-active substructures and medici-
nal-chemistry targets.[1] Over the past decade, the Buch-
wald–Hartwig amination of electrophilic aromatics involving
Pd,[2] Cu,[3] and Ni[4] centers has become a prominent and el-
ready have some related precedent for the cross-coupling of
cobalt-generated organozincs with a range of electrophiles
that is catalyzed by the residual cobalt salts in the
medium.[13]
À
egant method for creating C N bonds and forming function-
Having recently reported a cross-coupling of aniline deriv-
atives and 2-chloropyrimidines in the presence of tolylzinc
bromide as a base,[14] we can now present a complementary
alized arylamines. More recently, catalytic systems based on
cobalt have also been reported.[5] However, all these reac-
tions require sophisticated and expensive ligands. Moreover,
stoichiometric amounts of base or high reaction tempera-
tures (usually around 1008C) are often necessary to achieve
the reactions. The milder conditions described for N-aryla-
tion reactions employ a Chan–Lam type[6] procedure, which
À
approach to C N bond formation that allows the coupling
of in situ generated arylzinc species with chloroamines,
again using cobalt salts as catalysts (Scheme 1). The trans-
À
involves the oxidative coupling of arylboronic acids with N
H containing compounds in the presence of copper. Never-
theless, this method requires long reaction times (up to
4 days at room temperature) and arylboronic acids that are
generally more expensive than the corresponding aryl hal-
ides. For these reasons, an alternative strategy that uses the
reaction of a nucleophilic organometallic reagent with an
electrophilic nitrogen source has recently started to attract
attention. These umpolung procedures have been reported
with stoichiometric Ti,[7] catalytic Ni[8] or Cu[9], and even
transition-metal free[10] catalytic systems. However, these
methods also suffer from some drawbacks in that they re-
quire either the use of ligands, diorganozinc reagents, more
toxic Ni catalysts,[11] or stoichiometric metal loadings. More-
over, high or very low temperatures are often necessary to
ensure a good yield. Thus, despite impressive recent prog-
ress, the development of a mild, inexpensive, and simple
procedure remains highly desirable. Arylzinc reagents,
whose synthesis is well understood,[12] are good candidates
as reaction partners, but their amination with electrophilic
amines such as chloroamines is underdeveloped. A few
years ago, we described the cobalt-catalyzed formation of
functionalized-arylzinc species from the corresponding hal-
ides or triflates,[12c–f] and it seems likely that the presence of
cobalt salts in these arylzinc solutions might catalyze forma-
Scheme 1. Cobalt-catalyzed electrophilic amination of arylzincs with N-
chloroamines.
formation allows various N-aryl compounds to be synthe-
sized from both a variety of functionalized arylzinc species
and N-chloroamines. The reactions take place at room tem-
perature, do not require supplementary addition of cobalt
À
for the C N bond formation, and work efficiently with two
functionalized partners. The high activity, broad scope, high
functional-group tolerance, and mild reaction conditions of
this catalytic system showcase its value for organic synthesis.
First investigations of the Co-catalyzed coupling of 4-fluo-
rophenylzinc bromide with N-chloropiperidine allowed a
preliminary optimization of the procedure (Table 1). The
aryl
ACHTUNGTRENzNGNU inc species is prepared from the corresponding aryl-
AHCTUNGTREGbNNNU romide (ArBr) in the presence of cobalt in acetonitrile, as
previously reported.[12c–f] When this reaction mixture was fil-
tered and added to the chloroamine (0.33 equiv with respect
to ArBr) without further addition of cobalt, 44% of the
cross-coupling product was obtained according to GC
(Table 1, entry 1). Gratifyingly, this GC yield can be im-
proved to 90% by concentrating the medium (Table 1,
entry 2). Decreasing the excess of ArBr to 1.5 equivalents
(instead of 3 equiv) did not affect the yield (Table 1,
entry 3), but an excess of N-chloroamine relative to aryl
bromide was detrimental (Table 1, entry 4). Filtration of the
arylzinc compound was found to be necessary (Table 1,
entry 5). To establish that cobalt plays a crucial role in the
[a] X. Qian, Z. Yu, Dr. A. Auffrant, Dr. C. Gosmini
Laboratoire “Hꢀtꢀroꢀlꢀments et Coordination”
Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex (France)
Fax : (+33)1-6933-4440
E-mail: corinne.gosmini@polytechnique.edu
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201300229.
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Table 1. Initial studies for C N bond formation of p-FC6H4ZnBr.
Table 2. The scope of co-catalyzed electrophilic amination of various
arylzinc bromides.
Yield[a]
[%]
À
FG
ArBr/N Cl
G
FG
ArZnX
[mmol]
T
[8C]
Product
Yield[a]
[%]
G
1
2
3
4
5
6
7
8
p-F
p-F
p-F
p-F
3:1
3:1
0.75
1.2
0.6
0.6
0.6
0.6
0.6
0.6
(44)
(90)
80(91)
(32)
(30)
(5)
1
2
3
4
5
6
7
p-CF3
3.2
3.2
2.8
3.2
3.0
3.0
2.6
0–RT
0–RT
0–50
0–50
0–50
0–50
0–50
1b
1c
1d
1e
1 f
1g
1h
79
55
65
82
m-CF3
p-CO2Et
p-CN
p-OMe
p-Me
1.5:1
1:1.5
1.5:1
1.5:1
1.5:1
1.5:1
p-F[b]
p-F[c]
p-F[d,e,f]
p-F[g]
71
53
o-OMe
42[b]
0
(10)
[a] Isolated yield based on chloroamine; [b] 42% yield as determined by
1
[a] Yields given are for isolated products, (except those in parentheses
that give crude yields as established by GC, with decane as internal
standard); [b] no filtration of ArZnBr; [c] 0.5 mmol (equal to the amount
of CoBr2) of MVK was added to the arylzinc species before injection
into the chloroamine solution; [d] commercial ArZnBr in THF; [e] com-
mercial ArZnBr in THF and subsequent replacement of THF by
CH3CN; [f] electrochemically prepared ArZnBr in CH3CN; [g] formation
of ArZnX in CH3CN (2 mL) and addition of THF (3 mL).
À
À
H NMR spectroscopy of the mixture of Ar N and traces of Ar Ar ob-
tained after chromatography, see Supporting Information for details.
the reaction rate was enhanced in all cases; with all reac-
tions being finished at room temperature after only 2 h
versus 4–6 h without additive (compare Tables 2 and 3).
Having established the general protocol, we explored the
scope of the reaction using various aryl halides and a variety
of N-chloroamines (Table 3). Aryl derivatives bearing many
subsequent coupling reaction, a few experiments were con-
ducted (Table 1, entries 6–8). MVK (methyl vinyl ketone) is
known to bind cobalt and to largely reduce or annihilate its
catalytic activity, while keeping the aryl zinc species
intact.[15] Under the optimized conditions (Table 1, entry 3)
with addition of one equivalent of methyl vinyl ketone
Table 3. The scope of aryl halides and N-chloroamines.
À
(MVK) to the arylzinc solution, only traces of the C N
product was found after 2 h or overnight stirring. Commer-
cial ArZnBr (in THF or after replacing THF by CH3CN) or
electrochemically generated ArZnBr in acetonitrile were
shown to give no coupling product when reacted with N-
chloropiperidine (Table 1, entry 7).[16] Moreover, the addi-
tion of THF in the medium gave poor yield of cross-cou-
pling product (Table 1, entry 8).
We then extended the scope of the reaction to various
aryl bromides (Table 2) using the optimized conditions
(Table 1, entry 3). Moderate to excellent yields were ob-
tained. However, the initial conditions were not satisfactory
for all substrates. For example, only traces of cross-coupling
product were observed when coupling N-chloropiperidine
and p-MeCOC6H4ZnBr or PhZnBr. Moreover, with other
N-chloroamines such as the N-chloropyrrolidine, the major
products resulted from chlorination or protonation of the
arylzincs.
Amines were found to circumvent this problem efficiently
and prevent side reactions,[10b] so triethylamine was added to
the reaction medium. We found that the optimal ratio is
1:0.4 for chloroamine/triethylamine (Table S1 in the Sup-
porting Information). With this modification, we were
pleased to observe the disappearance of the side products
and the successful formation of arylamines for cases in
which previously no reaction occurred. More importantly,
FG
ArZnX
[mmol]
Product
Yield[a]
[%]
AHCTUNGTRENNUNG
1
2
p-CO2Et
H
2.8
3.0
1d 75
1i
82
3
p-COMe
2.8
1j 81
4
5
6
o-OMe
p-OCOMe
p-Cl
2.6
3.2
3.4
1h 39
1k 71
1l
80
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Cobalt-Catalyzed Electrophilic Amination
Table 3. (Continued)
COMMUNICATION
was also successfully extended to acyclic functionalized
amines (Table 3, entries 15–18).
FG
ArZnX
[mmol]
Product
Yield[a]
[%]
We then tried to extend with methodology to arylchloride
derivatives. We have previously established that cobalt catal-
ysis allows the simple and high-yielding preparation of a
broad range of functionalized arylzinc species from readily
available aryl chlorides,[12e,f] nevertheless, this step requires
the presence of pyridine, which hampers the amination.
AHCTUNGTRENNUNG
7
8
p-SO2Me
p-F
3.0
3.2
1m 64[b]
2a 53
2b 88
À
Therefore, only traces of C N product were observed with
aryl chlorides after several attempts. Amination of hetero-
AHCTUNGTRENNUNG
9
m-OMe
3.2
some N-chloroamines[16] can be difficult to isolate, especially
those prepared from primary amines. Thus, we developed a
protocol that avoids the isolation of the N-chloroamine.[7,8b]
The key lies in eliminating the succinimide coproduct that
would otherwise consume a large excess of the arylzinc spe-
cies. Therefore the preparation of the N-chloroamine was
achieved in toluene, which allowed the expedient removal
of the insoluble succinimide by filtration using a syringe
filter (see Supporting Information for details). The succini-
mide-free chloroamine solution was then added to the aryl-
10 o-Cl
2.8
3.0
2c 51
3a 67
11 p-SMe
12 m-CN
3.0
3b 72
À
zinc solution. Under these conditions, the C N bond forma-
tion was observed even from primary amines (Table 4).
Both linear (Table 4, entries 1 and 2) and branched
amines (Table 4, entries 3 and 4) yielded the desired prod-
ucts. More importantly, the introduction of the primary ben-
zylamine fragment worked well (Table 4, entry 5), which is
unusual for electrophilic amination procedures. Allyl sub-
stituents are also compatible (Table 4, entry 6). An N-Boc
group (Boc=tert-butyloxycarbonyl) and an aryl-Cl moiety
tolerated the amination conditions, which opens up potential
for further functionalization by traditional cross coupling
methods (Table 4, entry 7). The cross-coupling reaction also
worked well with only one sterically-hindered substituent on
the nitrogen (Table 4, entry 8), whereas no coupling product
was obtained with two bulky groups on the nitrogen atom.
Concerning the mechanism, some previous work on the
cobalt catalyzed formation of the arylzinc species in acetoni-
trile allows a pathway to be proposed.[10a,17] The in situ
formed CoI catalyzes the formation of the arylzinc com-
pounds in acetonitrile. It was also shown that cobalt remains
in the solution after filtration of the zinc dust which allows
further reactivity.[18] 1) The CoI center undergoes an oxida-
tive addition with the electrophilic N-chloroamine to afford
a CoIII species. 2) This CoIII species is transmetalated with
13 1,2-(methylenedioxy) 3.0
4a 68
14 p-F
3.2
3.4
3.2
4b 52
5a 61
5b 71[c]
15 3,5-diCF3
16 m-OMe
17 p-OMe
18 p-F
3.0
3.2
6a 80
6b 53
[a] Isolated yield based on chloroamine; [b] 64% yield as determined by
1
À
À
H NMR spectroscopy of the mixture of Ar N and traces of Ar Ar ob-
tained after chromatography, see Supporting Information for details;
[c] 71% yield as determined by 1H NMR spectroscopy of the mixture of
À
À
Ar N and traces of Ar Ar obtained after chromatography, see Support-
ing Information for details.
1
2
III
À
the arylzinc halides to furnish R R N Co -Ar. 3) The cycle
is completed by a reductive elimination (3), which produces
I
À
functional groups such as ketone, acetate, sulfone, chlorine,
fluorine, nitrile, trifluoromethyl, methoxy, thioether or diox-
ane groups in ortho, meta, or para positions were all success-
fully coupled at room temperature (Table 3). Furthermore
cyclic N-chloroamines, such as N-chloromorpholine, N-chlo-
the C N product and regenerates Co . This putative mecha-
nism is presented in Scheme 2.
In summary, we have developed a mild and highly effi-
cient procedure for the amination of functionalized arylzinc
reagents by secondary and tertiary N-chloroamines using
cobalt catalysis. This simple and convenient protocol dis-
plays a wide substrate scope, and a tolerance to a large
number of important functional groups. In some cases, tri-
ACHTUNGTRENNUNGropyrrolidine, and N-chloropiperidine bearing an ester
group, provide good to excellent yields when treated with
various arylzinc species bearing either electron-donating or
withdrawing groups (Table 3, entries 1–14). The reaction
AHCTUNGTREGeNNNU thylamine dramatically improved the reaction of the aryl-
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C. Gosmini et al.
Table 4. Amination with non-isolated N-chloroamines.
Experimental Section
General procedures for amination of arylzinc reagents: To a solution of
CoBr2 (0.5 mmol, 0.13 equiv, 110 mg) and zinc powder (10 mmol,
2.67 equiv, 0.65 g) in acetonitrile (4 mL) at room temperature were suc-
cessively added allylchloride (1.5 mmol, 125 mL) and trifluoroacetic acid
(50 mL), causing an immediate rise in temperature and color change to
dark gray. After stirring the resulting mixture for 3 min, aryl bromide
(3.75 mmol, 1.0 equiv) was added. The reaction was followed by GC on
iodolyzed aliquots. Once all the starting bromide was consumed (30–
60 min), stirring was interrupted; the reaction medium was taken in a
10 mL syringe, and the zinc dust filtered through a syringe filter. The fil-
tered arylzinc solution was injected into a solution of freshly prepared N-
chloroamine (2.5 mmol, 0.67 equiv) and triethylamine (1 mmol,
0.27 equiv) in acetonitrile (1 mL), which was placed in an oven-dried
Schlenk flask under N2 and cooled to 08C. The ice bath was allowed to
melt, allowing the reaction to slowly warm to room temperature. After
2 h, the reaction was quenched with a saturated solution of NH4Cl. The
aqueous layer was extracted with diethylether or ethylacetate (3ꢂ20 mL)
and the combined organic layers were dried over MgSO4, filtered and
concentrated under vacuum. Purification was performed using silica gel
column chromatography, with a gradient from 99:1 to 8:2 petroleum
ether/diethylether and several drops of NEt3, affording the corresponding
arylamine cross-coupling product.
FG
ArZnX
[mmol]
Product
Yield[a]
[%]
ACHTUNGTRENNUNG
1
3,5-dimethyl
3.0
7a
70[b]
2
3
4
o-OMe
p-OMe
p-F
2.8
2.8
3.2
7b
8a
8b
80
78
58
5
p-CF3
3.2
9
78
6
7
8
p-OCOMe
p-Cl
3.0
3.0
3.2
10
11
12
39
58
58
Acknowledgements
We gratefully acknowledge M. Flaus and L. Delvos for initial experi-
ments, and the team of Dr. E. Magnier who allowed us to record the
19F NMR spectra.
À
Keywords: amination · anilines · C N coupling · cobalt ·
p-F
zinc
[a] Isolated yield based on amine; [b] 70% yield as determined by
1
À
À
H NMR of the mixture of Ar N and traces of Ar Ar obtained after
chromatography, see Supporting Information for details.
[1] a) K. Weissermel, H. J. Arpe, Industrial Organic Chemistry, Wiley-
VCH, Weinheim, 1997; b) S. A. Lawrence, Amines: Synthesis Prop-
erties and Applications, University Press, Cambridge, 2004; c) R.
Hili, A. K. Yudin, Nat. Chem. Biol. 2006, 2, 284–287; d) T. J.
Barker, E. R. Jarvo, Synthesis 2011, 3954–3964.
[2] a) J. F. Hartwig, Acc. Chem. Res. 2008, 41, 1534–1544; b) D. S. Surry,
S. L. Buchwald, Chem. Sci. 2011, 2, 27–50.
[3] a) A. Shafir, S. L. Buchwald, J. Am. Chem. Soc. 2006, 128, 8742–
8743; b) S. Guo, B. Qian, Y. Xie, C. Xia, H. Huang, Org. Lett. 2010,
13, 522–525; c) X. Diao, L. Xu, W. Zhu, Y. Jiang, H. Wang, Y. Guo,
D. Ma, Org. Lett. 2011, 13, 6422–6425.
[4] a) J. P. Wolfe, S. L. Buchwald, J. Am. Chem. Soc. 1997, 119, 6054–
6058; b) J. Pawlas, Y. Nakao, M. Kawatsura, J. F. Hartwig, J. Am.
Chem. Soc. 2002, 124, 3669–3679; c) S. Tasler, B. H. Lipshutz, J.
Org. Chem. 2003, 68, 1190–1199; d) B. M. Rosen, K. W. Quasdorf,
D. A. Wilson, N. Zhang, A.-M. Resmerita, N. K. Garg, V. Percec,
Chem. Rev. 2011, 111, 1346–1416; e) L. Hie, S. D. Ramgren, T. Mes-
ganaw, N. K. Garg, Org. Lett. 2012, 14, 4182–4185.
Scheme 2. Postulated catalytic cycle.
[5] a) Y. C. Teo, G. L. Chua, Chem. Eur. J. 2009, 15, 3072–3075; b) G.
Toma, K.-I. Fujita, R. Yamaguchi, Eur. J. Org. Chem. 2009, 4586–
4588.
[6] a) S. V. Ley, A. W. Thomas, Angew. Chem. 2003, 115, 5558–5607;
Angew. Chem. Int. Ed. 2003, 42, 5400–5449; b) J. X. Qiao, P. Y. S.
Lam, Synthesis 2011, 2011, 829–856; c) N. Matsuda, K. Hirano, T.
Satoh, M. Miura, Angew. Chem. 2012, 124, 3702–3705; Angew.
Chem. Int. Ed. 2012, 51, 3642–3645; d) R. P. Rucker, A. M. Whittak-
er, H. Dang, G. Lalic, Angew. Chem. 2012, 124, 4019–4022; Angew.
Chem. Int. Ed. 2012, 51, 3953–3956.
zinc species with the N-chloroamine and prevents the for-
mation of byproducts. This method is attractive for the
streamlined synthesis of functional molecules. Further stud-
ies to extend the scope of this methodology and to gain de-
tailed mechanistic insight are currently underway in our
laboratory.
&
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Chem. Eur. J. 0000, 00, 0 – 0
ÝÝ
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Cobalt-Catalyzed Electrophilic Amination
COMMUNICATION
[7] T. J. Barker, E. R. Jarvo, Angew. Chem. 2011, 123, 8475–8478;
Angew. Chem. Int. Ed. 2011, 50, 8325–8328.
[8] a) A. M. Berman, J. S. Johnson, Synlett 2005, 2005, 1799–1801;
b) T. J. Barker, E. R. Jarvo, J. Am. Chem. Soc. 2009, 131, 15598–
15599.
[9] a) A. M. Berman, J. S. Johnson, J. Am. Chem. Soc. 2004, 126,
56805681; b) A. M. Berman, J. S. Johnson, J. Org. Chem. 2006, 71,
219–224; c) M. J. Campbell, J. S. Johnson, Org. Lett. 2007, 9, 1521–
1524; d) C. He, C. Chen, J. Cheng, C. Liu, W. Liu, Q. Li, A. Lei,
Angew. Chem. 2008, 120, 6514–6517; Angew. Chem. Int. Ed. 2008,
47, 6414–6417; e) T. Kawano, K. Hirano, T. Satoh, M. Miura, J. Am.
Chem. Soc. 2010, 132, 6900–6901.
[10] a) P. Sinha, P. Knochel, Synlett 2006, 3304–3308; b) T. Hatakeyama,
Y. Yoshimoto, S. K. Ghorai, M. Nakamura, Org. Lett. 2010, 12,
1516–1519; c) Q. Xiao, L. Tian, R. Tan, Y. Xia, D. Qiu, Y. Zhang, J.
Wang, Org. Lett. 2012, 14, 4230–4233.
[11] a) Handbook on the Toxicology of Metals (Eds.: L. Friberg, G. F.
Nordberg, V. B. Vouk), Elsevier, Amsterdam, 1986; b) M. N.
Hughes, in Comprehensive Coordination Chemistry Vol. 6 (Eds: G.
Wilkinson, R. D. Gillard, J. A. McCleverty, Pergamon, Oxford, 1987,
pp. 643–648; c) Nickel and the Skin: Absorption, Immunology, Epi-
demiology, and Metallurgy (Eds.: J. J. Hostynek, H. I. Maibach),
CRC, Boca Raton, 2002.
[12] a) C. I. Stathakis, S. Bernhardt, V. Quint, P. Knochel, Angew. Chem.
2012, 124, 9563–9567; Angew. Chem. Int. Ed. 2012, 51, 9428–9432;
b) P. Knochel, H. Leuser, L.-Z. Gong, S. Perrone, F. F. Kneisel, in
Handbook of Functionalized Organometallics (Ed.: P. Knochel),
Wiley-VCH, Weinheim, 2005, pp 251–333; c) H. Fillon, C. Gosmini,
J. Pꢀrichon, J. Am. Chem. Soc. 2003, 125, 3867–3870; d) I. Kazmier-
ski, C. Gosmini, J. M. Paris, J. Pꢀrichon, Tetrahedron Lett. 2003, 44,
6417–6420; e) C. Gosmini, M. Amatore, S. Claudel, J. Pꢀrichon,
Synlett 2005, 2171–2174; f) I. Kazmierski, C. Gosmini, J. M. Paris, J.
Pꢀrichon, Synlett 2006, 881–884.
[13] a) C. Gosmini, J. M. Bꢀgouin, A. Moncomble, Chem. Commun.
2008, 3221–3233; b) C. Gosmini, A. Moncomble, Isr. J. Chem. 2010,
50, 568–576.
[14] L. B. Delvos, J. M. Begouin, C. Gosmini, Synlett 2011, 2325–2328.
[15] M. Amatore, C. Gosmini, Synlett 2009, 1073–1076.
[16] J. C. Guillemin, J. M. Denis, Synthesis 1985, 1985, 1131–1133.
[17] S. Seka, O. Buriez, J.-Y. Nꢀdꢀlec, J. Pꢀrichon, Chem. Eur. J. 2002, 8,
2534–2538.
[18] M. Amatore, C. Gosmini, Chem. Commun. 2008, 5019–5021.
Received: January 21, 2013
Published online: && &&, 0000
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C. Gosmini et al.
Synthetic Methods
X. Qian, Z. Yu, A. Auffrant,
C. Gosmini* ................... &&&& — &&&&
Roles reversed: An efficient cobalt-
catalyzed electrophilic amination of
arylzinc reagents reaction has been
achieved. A variety of functionalized
arylzincs and N-chloroamines were
coupled under mild conditions (see
Cobalt-Catalyzed Electrophilic Amina-
tion of Arylzincs with N-Chloroamines
scheme). Both secondary and tertiary
arylamines were obtained in moderate
to excellent yields.
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Chem. Eur. J. 0000, 00, 0 – 0
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These are not the final page numbers!