Ni-catalyzed arylation of bromomagnesium diarylamides with aryl N,N-dimethylsulfamates

Article abstract of DOI:10.1016/j.tetlet.2012.08.015

The combination use of Ni(cod)₂ and N,N-1,3-bis(2,6- diisopropylphenyl)-4-imidazoline-2-ylidene as a catalyst successfully gave unsymmetrical N,N-diaryl-N′,N′-diphenyl-1,1′-biphenyl-4, 4′-diamines through the arylation of bromomagnesium diarylamide with 1-(4′-diphenylamino-1,1′-biphenylyl) N,N-dimethylsulfamate. This Ni catalyst and Grignard reagents of diaryl or monoarylamides were also useful in the syntheses of various triarylamines and diarylamines from corresponding aryl N,N-dimethylsulfamates. 2012 Elsevier Ltd. All rights reserved.

Full text of DOI:10.1016/j.tetlet.2012.08.015

Tetrahedron Letters 53 (2012) 5531–5534
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Ni-catalyzed arylation of bromomagnesium diarylamides with aryl
N,N-dimethylsulfamates
⇑
Hiroshi Tadaoka, Tetsu Yamakawa
Sagami Chemical Research Institute, Catalysis Group, Hayakawa 2743-1, Ayase, Kanagawa 252-1193, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
The combination use of Ni(cod)2 and N,N-1,3-bis(2,6-diisopropylphenyl)-4-imidazoline-2-ylidene as a
catalyst successfully gave unsymmetrical N,N-diaryl-N0,N0-diphenyl-1,10-biphenyl-4,40-diamines through
the arylation of bromomagnesium diarylamide with 1-(40-diphenylamino-1,10-biphenylyl) N,N-dim-
ethylsulfamate. This Ni catalyst and Grignard reagents of diaryl or monoarylamides were also useful in
the syntheses of various triarylamines and diarylamines from corresponding aryl N,N-
dimethylsulfamates.
Received 15 June 2012
Revised 31 July 2012
Accepted 3 August 2012
Available online 10 August 2012
Keywords:
Ó 2012 Elsevier Ltd. All rights reserved.
Unsymmetrical 1,10-biphenyl-4,40-diamine
Ni catalyst
Arylation
Arylamine synthesis
Symmetrical 1,10-biphenyl-4,40-diamine compounds A having
the same diarylamino (NAr2) groups at the 4- and 40-positions such
as N,N0-di(1-naphthyl)-N,N0-diphenyl-1,10-biphenyl-4,40-diamine
routes for a highly selective synthesis of B. Nevertheless, chlorine-
substituted biphenyls cannot be used because of their toxicity.
Recently, Pd- or Ni-catalyzed arylation of H2NAr and HNAr2
through C–O bond cleavage has been reported;7 substrates in this
arylation are readily synthesized from phenols, Ar–OH. Among
them, we were much interested in the arylation using aryl sulfo-
nates or sulfamates Ar–OSO2R,8–15 particularly in the Ni-catalyzed
arylation with aryl N,N-dimethylsulfamates Ar–OSO2NMe2.8,9
Thus, since the Pd-catalyzed arylation with similar substrate, Ar–
OSO2(imidazolyl), requires 2-dicyclohexyl-20,40,60-triisopropylbi-
phenyl (X-Phos) or rac-BINAP as a phosphine ligand,8 –OSO2NMe2
group is considered to remain intact in the arylation using a con-
ventional Pd catalyst. Then, we examined the arylation of HNPh2
with 4-(40-bromo)-1,10-biphenylyl N,N-dimethylsulfamate a,
which was obtained from 40-bromo-1,10-biphenyl-4-ol and N,
N-dimethylsulfamoyl chloride in a satisfactory yield,16 in the pres-
ence of Pd(dba)2 and a conventional phosphine ligand. As a result,
only 4-(40-diphenylamino)-1,10-biphenylyl N,N-dimethylsulfamate
b was obtained as shown in Scheme 2.17 N,N,N0,N0-Tetraphenyl-
1,10-biphenylyl-4,40-diamine was not detected at all even when
2.0 equiv of HNPh2 to a was used. Of the phosphine ligands tested,
(a
-NPD), N,N0-di-m-tolyl-N,N0-diphenyl-1,10-biphenyl-4,40-diamine
(TPD), and 4,40-bis(N-carbazolyl)-1,10-biphenyl (CBP) are widely
used in organic light-emitting diodes (OLEDs).1 The development
in the Pd-2 or Ni-catalyzed3 arylation of amines with aryl halides
(the Buchwald–Hartwig amination) has led to the synthesis of a
wide variety of such symmetrical compounds. On the other hand,
unsymmetrical 1,10-biphenyl-4,40-diamine compounds B that have
different NAr2 group at the 4- and 40-positions would be desirable
candidates for OLEDs’ materials with improved efficiency.4 These
compounds B are possibly synthesized through arylation of one
HNAr2 with a 4,40-dihalo-1,10-biphenyl C to form diaryl(40-halo-
biphenylyl)amine intermediate D followed by arylation of other
HNAr2 with obtained D. Indeed, as depicted in Scheme 1, the synthe-
ses of B from C1 using a Cu catalyst (the Ulmann reaction)5a,5b and
from C2 using a Pd catalyst5c have been already reported; D1 was
obtained as an intermediate in both reactions. Although these re-
ports make no mention of the formation of symmetrical A as by-
products via further arylation at the 40-position of D1, it might be
difficult to control the selectivity in this reaction. The Pd/PtBu3 is a
well-known catalyst for the arylation of HNAr2 with aryl chlorides,6
a chlorine atom in which is generally intact in the arylation with
conventional Pd catalysts. This suggests that successive arylation
of two kinds of HNAr2 with C3 by a conventional Pd catalyst and
Pd/PtBu3 via D2 as an intermediate would be one of the promising
18
P(o-tolyl)3 gave the highest yield of b (Scheme 2). Since a rather
uncommon ligand, (20-isoproxy-1,10-binaphthylenyl-2-yl)-di-tert-
butylphosphine, is necessary in the Pd-catalyzed arylation with
Ar–OSO2(p-tolyl),13 –OSO2(p-tolyl) group can be also intact during
the arylation with a conventional Pd catalyst. However, this type of
substrates were not adopted due to their low reactivity in the Ni-
catalyzed arylation (vide infra).
In this way, we obtained the promising intermediate b for
⇑
Corresponding author. Tel.: +81 467769268; fax: +81 467774113.
E-mail address: t_yamakawa@sagami.or.jp (T. Yamakawa).
the synthesis of unsymmetrical N,N-diaryl-N0,N0-diphenyl-1,
0040-4039/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tetlet.2012.08.015

5532
H. Tadaoka, T. Yamakawa / Tetrahedron Letters 53 (2012) 5531–5534
Ar1
N H
Ar1
Ar2
Ar1
Ar2
Ar1
Ar2
Ar2
X2
N
N
X1
X2
+
N
C1 : X1 = I, X2 = Br
C2 : X1 = X2 = Br
D1 : X2 = Br
D2 : X2 = Cl
A
C3 : X1 = Br or I, X2 = Cl
Ar3
H N
Ar1
Ar2
Ar3
Ar4
N
N
Ar4
B
Scheme 1. Syntheses of unsymmetrical B from C.
Br
Br
OH
ClSO2NMe2
Pd(dba)2 (5 mol%)
ligand (10 mol%)
NaOtBu (1.25 equiv)
+
OSO2NMe2
OSO2NMe2
N
H N
toluene, 100 ഒ, 24 h
a
87%
b
1.25 equiv
ligand = P(o-tolyl)3 : 76%
PCy3 : 49%
PPh3 : 40%
DPPF : 40%
Scheme 2. Pd-catalyzed arylation of HNPh2 with a.
Table 1
Syntheses of (4-biphenylyl)diphenylamine through Ni-catalyzed arylation of HNPh2 or BrMg(NPh2)a
Ni precursor (10 mol%)
ligand
base (1.5 equiv)
+
N
X
N
OSO2NMe2
1,4-dioxane, 150 °C, 24 h
c
Entry
X
Ni precursor
Ligand
Base
Yield/%
1
2
3
4
5
H
H
H
BrMg
BrMg
Ni(cod)2
Ni(cod)2
Ni(cod)2
NiCl2(PPh3)2
Ni(cod)2
DPPF (10 mol%)
IPr (20 mol%)b
SIPr (20 mol%)c
PPh3 (20 mol%)
IPr (20 mol%)
NaOtBu
NaOtBu
NaOtBu
None
0
0.6
0
38
69
None
a
b
c
[Ni precursor] = 9.4 mM.
IPr: N,N-1,3-bis(2,6-diisopropylphenyl)-4-imidazoline-2-ylidene.
SIPr: N,N-1,3-bis(2,6-diisopropylphenyl)-4-imidazolidine-2-ylidene.
10-biphenyl-4,40-diamines from 40-bromo-1,10-biphenyl-4-ol. Next
challenge is the arylation of HNAr2 with thus obtained sulfamate
b. To the best of our knowledge, the Ni-catalyzed arylation with
aryl sulfonates was exclusively carried out using aniline or N-
monoalkylated aniline derivatives to produce HNAr2 or NAr2R
(R = alkyl).8–14 Thus, the Ni-catalyzed arylation of HNAr2 with aryl
sulfonates is considered rather difficult.19 Indeed, the Ni catalysts
that catalyze the arylation of aniline or N-monoalkylated aniline
derivatives with aryl sulfonates8,9 afforded virtually no product
in the arylation of HNPh2 with 4-biphenylyl N,N-dimethylsulfa-
mate (entries 1–3 in Table 1). Recently, Yang and co-worker re-
ported that the NiCl2(PPh3)2/PPh3-catalyzed arylation with aryl
iodides or bromides proceeded smoothly to give NAr3 when using
bromomagnesium diarylamides, BrMg(NAr2).20 However, this
method exhibited low reactivity in this arylation (entry 4). In
contrast, the combination use of Ni(cod)2 and N,N-1,3-bis(2,6-
diisopropylphenyl)-4-imidazoline-2-ylidene (IPr) catalyst pro-
vided the satisfactory yield (entry 5).
Then we performed the arylation of several BrMg(NAr2) with b
by the use of the Ni(cod)2/IPr catalyst. The results are listed in Ta-
ble 2.17 The arylation successfully proceeded, but the yields were
unsatisfactory. Nevertheless, the syntheses of the unsymmetrical
products, e and f, would be the first example of Ni-catalyzed aryla-
tion. The ability of the compound f to function as a hole-transport
material in OLEDs has been investigated and reported in a recent
patent.4 In that study, since the test sample was synthesized
through Pd(OAc)2/PtBu3/NaOtBu-catalyzed arylation of HNPh2 and
HN(p-tolyl)2 with 4,40-diiodo-1,10-biphenyl,
a mixture of e,
N,N,N0,N0-tetra-p-tolyl-1,10-biphenyl-4,40-diamine, and N,N,N0,N0-
tetraphenyl-1,10-biphenyl-4,40-diamine was obtained. Therefore,

H. Tadaoka, T. Yamakawa / Tetrahedron Letters 53 (2012) 5531–5534
5533
Table 2
Syntheses of N,N-diaryl-N0,N0-diphenyl-1,10-biphenyl-4,40-diamines through Ni(cod)2/IPr-catalyzed arylation of BrMg(NAr2) with ba
Ni(cod)2 (10 mol%)
IPr (20 mol%)
Ar
Ar
Ar
Ar
N
+
N
OSO2NMe2
N
BrMg N
1,4-dioxane, 150 ഒ
b
Entry
Ar
Reaction time/h
Yield/%
1
2
3
43
24
24
55 (d)
30 (e)
51 (f)
Me
MeO
a
[Ni(cod)2] = 9.4 mM.
it does not mean that the hole-transport ability of e was indepen-
dently examined. The other synthetic method of unsymmetrical B
including e involves three steps;21 (i) bromination of two kinds of
NAr2Ph to NAr2(C6H4-4-Br), (ii) preparation of the Grignard reagent
of one NAr2(C6H4-4-Br), and (iii) the Kumada coupling of resulting
Grignard reagent and the other NAr2(C6H4-4-Br). In this method,
the selective bromination only at the para-position of phenyl group
in NAr2Ph is required in the step (i). Our method is superior to
these reported methods in terms of its simplicity and selectivity.
Next, we carried out the arylation using the Ni(cod)2/IPr catalyst
to synthesize NAr3 and HNAr2 from various BrMg(NAr2) or
BrMg(HNAr) and aryl N,N-dimethylsulfamates. The sulfamates
were also readily obtained from the corresponding phenols and
N,N-dimethylsulfamoyl chloride.16 The results are listed in
Table 3.17,22 Triarylamines having phenyl, 1-naphthyl, 2-naphthyl
or 4-biphenylyl groups were obtained in moderate yields except
g and m which have three different aryl groups (entries 1–8). In
the case of 2-biphenylyl N,N-dimethylsulfamate, the bulkiness of
2-biphenylyl group probably caused the low yield (entry 9, n).
The reactivity of phenyl or substituted-phenyl N,N-dimethylsulfa-
mates was very low. The yields of the product o and p were barely
exceeded 10% (entries 10 and 11); phenyl or 4-methoxyphenyl
N,N-dimethylsulfamates did not afford the product at all. In con-
trast to the arylation of BrMg(NAr2), the arylation of BrMg(HNAr)
smoothly progressed. Particularly, the yields of s (entry 14) and t
(entry 15) were much improved compared with entries 9 and 4.
Table 3
Syntheses of NAr3 and HNAr2 through Ni(cod)2/IPr-catalyzed arylationa
Ni(cod)2 (10 mol%)
IPr (20 mol%)
Ar2
Ar2
Ar1 OSOMe2
Ar1
N
+
BrMg N
1,4-dioxane, 150 °C, 24 h
Ar3
Ar1
Ar3
Entry
1b
Ar1
Ar2
Ar3
Yield/%
Entry
12
Ar2
Ar3
H
Yield/%
76 (c)
70 (q)
2c
3
78 (g)
84 (h)
13
14
H
H
75 (r)
67 (s)
4
5
16 (i)
59 (j)
15
16
H
H
58 (t)
76 (u)
Me
Me
6
44 (k)
17
H
26 (v)
OMe
OMe
7
8
55 (l)
22 (m)
9
27 (n)
10
11
17 (o)
10 (p)
F
CH2O
a
b
c
[Ni(cod)2] = 9.4 mM.
The reaction time was 43 h. The yield obtained in 24 h reaction was 69% (see Table 1).
The reaction temperature was 110 °C.

5534
H. Tadaoka, T. Yamakawa / Tetrahedron Letters 53 (2012) 5531–5534
10. Huang, X.; Anderson, K. W.; Zim, D.; Jiang, L.; Klapars, A.; Buchwald, S. L. J. Am.
Chem. Soc. 2003, 125, 6653–6655.
11. Anderson, K. W.; Mendez-Perez, M.; Priego, J.; Buchwald, S. L. J. Org. Chem.
2003, 68, 9563–9573; (b) Tundel, R. E.; Anderson, K. W.; Buchwald, S. L. J. Org.
Chem. 2006, 71, 430–433.
12. Gao, C.-Y.; Yang, L.-M. J. Org. Chem. 2008, 73, 1624–1627.
13. Xie, X.; Ni, G.; Ma, F.; Ding, L.; Xu, S.; Zhang, Z. Synlett 2011, 955–958.
14. (a) Wolfe, J. P.; Buchwald, S. L. J. Org. Chem. 1997, 62, 1264–1267; (b) Wolfe, J.
P.; Tomori, H.; Sadighi, J. P.; Yin, J.; Buchwald, S. L. J. Org. Chem. 2000, 65, 1158–
1174.
On the other hand, the yield of (2-biphenylyl)(1-naphthyl)amine v
was low presumably due to the repulsion between 2-biphenylyl
and 1-naphthyl groups.
The reaction of 2-naphthyl tosylate and BrMg(NPh2) under the
same condition as entry 1 afforded the product g in 46% yield. In
addition, the yield of g was 47% when using sodium diphenylam-
ide. These results indicate the advantage of the combination use
8,9
of Ar–SO2NMe2 and BrMg(NAr2) for the present arylation just
15. So, C. M.; Zhou, Z.; Lau, C. P.; Kwong, F. Y. Angew. Chem., Int. Ed. 2008, 47, 6402–
6406.
like the results in Table 1.
In conclusion, we presented a new route to unsymmetrical 1,10-
biphenyl-4,40-diamine compounds from 40-bromo-1,10-biphenyl-4-
ol through reaction with ClSO2NMe2 and successive arylation with
a conventional Pd catalyst and Ni(cod)2/IPr catalyst. The latter Ni-
catalyzed arylation was applicable to the synthesis of a wide range
of NAr3 and HNAr2 which will be promising raw materials in vari-
ous fields. The development of more active Ni catalysts is currently
under investigation.
16. (a) Wolfe, J. P.; Wagaw, S.; Buchwald, S. L. J. Am. Chem. Soc. 1996, 118, 7215–
7216; (b) Driver, M. S.; Hartwig, J. F. J. Am. Chem. Soc. 1996, 118, 7217–7218.
17. Characterization of new compounds: 4-(40-bromo)-1,10-biphenylyl N,N-
dimethylsulfamate (a): white solid. Mp: 110.9–111.6 °C. 1H NMR (CDCl3,
400 MHz): d 3.01 (6H, s), 7.35 (2H, d, J = 8.5 Hz), 7.41 (2H, d, J = 8.5 Hz), 7.55
(2H, d, J = 8.5 Hz), 7.56 (2H, d, J = 8.5 Hz). 13C NMR (CDCl3, 100 MHz): d 38.8,
121.9, 122.2, 128.3, 128.7, 132.0, 138.6, 138.9, 149.9. IR (neat): 2366, 1479,
1358, 1173, 1151, 960, 854, 816, 769, 729, 698 cmꢀ1
14H14NO3SBr: 354.9878. Found: 354.9873. 4-(40-diphenylamino)-1,1-
. HRMS: Calcd for
C
biphenylyl N,N-dimethylsulfamate (b): white solid. Mp: 129.4–132.8 °C. 1H
NMR (CDCl3, 400 MHz): d 2.99 (6H, s), 7.04 (2H, t, J = 7.4 Hz), 7.11–7.14 (6H,
m), 7.24–7.34 (6H, m), 7.40–7.43 (2H, m), 7.54–7.57 (2H, m). 13C NMR (CDCl3,
100 MHz): d 55.5, 114.7, 120.9, 122.7, 124.2, 126.5, 127.06, 127.11, 129.2,
132.7, 135.1, 141.0, 146.4, 147.7, 147.8, 155.8. IR (neat): 2925, 1730, 1585,
1485, 1362, 1273, 1147, 978, 866, 852, 827, 721, 692 cmꢀ1. HRMS: Calcd for
C26H24N2O3S: 444.1508. Found: 444.1507. N,N-bis(4-methoxyphenyl)-N0,N0-
diphenyl-1,10-bipheny-4,40-diamine (d): yellow solid. Mp: 128.8–131.8 °C. 1H
NMR (CDCl3, 400 MHz): d 3.80 (6H, s), 6.81–6.85 (4H, m), 6.95–7.03 (4H, m),
7.05–7.13 (10H, m), 7.23–7.27 (4H, m), 7.36–7.44 (4H, m). 13C NMR (CDCl3,
100 MHz): d 38.8, 122.0, 123.1, 123.7, 124.6, 127.8, 127.9, 129.3, 133.6, 139.4,
147.5, 147.6, 149.2. IR (neat): 3032, 2954, 2360, 1587, 1489, 1273, 1236, 1034,
818, 754, 694 cmꢀ1. HRMS: Calcd for C38H32N2O2: 548.2464. Found: 548.2455.
(1-naphthyl)(2-naphthyl)phenylamine (i): yellow solid. Mp: 67.2–70.0 °C. 1H
NMR (CDCl3, 400 MHz): d 6.96 (1H, tt, J = 7.2 Hz, 1.1 Hz), 7.06–7.09 (2H, m),
7.19–7.24 (2H, m), 7.27–7.36 (6H, m), 7.42–7.51 (3H, m), 7.67 (1H, d,
J = 9.5 Hz), 7.72 (1H, d, J = 7.4 Hz), 7.79 (1H, d, J = 8.2 Hz), 7.89 (1H, d,
J = 8.4 Hz), 7.96 (1H, d, J = 8.5 Hz). 13C NMR (CDCl3, 100 MHz): d 117.6, 122.0,
122.2, 122.9, 124.1, 124.3, 126.19, 126.24, 126.4, 126.47, 126.54, 126.9, 127.3,
127.5, 128.4, 128.8, 129.2, 129.5, 131.2, 134.4, 135.3, 143.6, 146.2, 148.5. IR
(neat): 3055, 2360, 2332, 1589, 1489, 1466, 1392, 1290, 1271, 771, 742,
694 cmꢀ1. HRMS: Calcd for C26H19N: 345.1517. Found: 345.1513.
Acknowledgment
We thank the associate professor Hirokazu Horino at University
of Toyama for HRMS characterization.
References and notes
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0.30 mmol), Ni(cod)2 (7.8 mg, 0.030 mmol), and 1,4-dioxane solution of IPr
(23.5 mM, 2.6 mL) were charged in a two-neck flask in Ar atmosphere. To the
resulting mixture, THF solution of bromomagnesium diphenylamide (1.0 M,
0.6 mL) was added dropwise. After stirring for 24 h at 110 °C, the product was
isolated using silica gel chromatography.
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