Y. Uozumi and Y. Hirai
FULL PAPERS
Coupling of haloarenes with diarylamines: A typical procedure is given
for the coupling of bromobenzene (3A) with diphenylamine (4) (Table 1,
entry 8).
A mixture of the catalyst (1-Pd complex (P/Pd=2:1),
0.015 mmol of Pd), bromobenzene (0.45 mmol), and diphenylamine
(0.30 mmol) in 20m KOH aqueous solution (0.6 mL) was shaken for 24 h
under reflux conditions in a nitrogen atmosphere. After being cooled, the
mixture was filtered, and the recovered resin beads were extracted with
EtOAc (2 mL, 4 times). The combined extracts were dried over anhy-
drous Na2SO4. The solvent was evaporated to give crude crystals of tri-
phenylamine (5A), which were evaluated for chemical purity and yield
by NMR and GC analysis (Table 2). Analytically pure 5A was obtained
by recrystallization from EtOAc/hexane. Triphenylamine (5A); CAS:
603–34–9; white crystals; 1H NMR (500 MHz, CDCl3, 258C): d=7.23 (t,
J=7.0 Hz, 6H), 7.08 (d, J=8.0 Hz, 6H), 6.99 (t, J=7.0 Hz, 3H);
13C NMR(125 MHz, CDCl3, 258C): d=147.8, 129.2, 124.1 122.6; MS
(EI(+)): m/z 245 (M+).
Scheme 7. Triple amination forming tris(4-diphenylaminophenyl)amine.
view toward using them in water. Aromatic amination of
aryl halides with diphenylamine and N,N-double arylation
of anilines with bromobenzene were found to proceed
smoothly in water with broad substrate tolerance to give tri-
arylamines in high yield with high recyclability of the poly-
meric catalyst beads. Since little palladium leached from the
polymeric catalyst under the water-based reaction condi-
tions, this method provides a green and clean (metal-uncon-
taminated) protocol for the preparation of triarylamines.
The catalytic system was applied to successive amination of
dibromoarenes and N,N,N’N’-quadruple arylation of phenyl-
enediamine producing N,N,N’N’-tetraarylphenylenediamines.
With the heterogeneous catalytic system, electroactive
N,N,N’,N’-tetraaryl-1,1’-biphenyl-4,4’-diamines (TPDs) were
obtained without metal contamination.
Acknowledgements
This work was supported by the Green-Sustainable Chemical Process
project sponsored by the METI/NEDO. We also thank the JSPS, the
MEXT, and the JST for partial financial support of this work.
[2] For reviews on heterogeneous-switching, see: a) D. C. Bailey, S. H.
Organic Synthesis on Solid Phase; Wiley-VCH, Weinheim, 2000;
g) Chiral Catalyst Immobilization and Recycling (Eds.: D. E.
De Vos, I. F. J. Vankelecom, P. A. Jacobs), Wiley-VCH, Weinheim,
2000; h) S. V. Ley, I. R. Baxendale, R. N. Bream, P. S. Jackson, A. G.
Leach, D. A. Longbottom, M. Nesi, J. S. Scott, R. I. Storer, S. J.
Curr. Chem. 2004, 242, 77; k) M. Guino, K. K. M. Hii, Chem. Soc.
[3] For reviews on aqueous-switching, see: a) C.-J. Li, T.-H. Chan, Or-
ganic Reactions in Aqueous Media, Wiley-VCH, New York, 1997;
b) P. A. Grieco, Organic Synthesis in Water, Kluwer Academic Pub-
lishers, Dordrecht, 1997; c) W. A. Herrmann, C. W. Kohlpaintner,
Li, T.-H. Chan, Comprehensive Organic Reactions in Aqueous
Media, Wiley-Interscience, New Jersey, 2007; f) Aqueous-Phase Or-
ganometallic Catalysis (Eds.: B. Cornils, W. A. Herrmann), Wiley-
VCH, Weinheim, 2004.
Experimental Section
Preparation of PS-PEG-P(tert-C4H9)2 (1): n-Butyllithium (2.69 molLÀ1 in
hexane, 0.47 mL, 1.25 mmol) was added to a mixture of di-tert-butylphos-
phine (1.83 g, 1.25 mmol) and THF (10 mL, three freeze–pump–thaw
cycles) over 1 h and the mixture was stirred at À788C for 1 h under a ni-
trogen atmosphere. The reaction mixture was added to the TentaGelꢁ
S
Br (2.01 g, 0.50 mmol of bromine residue) dispersed in THF (20 mL,
three freeze–pump–thaw cycles) at À788C under a nitrogen atmosphere
and the resulting mixture was stirred for 1 h. The reaction mixture was
warmed to room temperature slowly (for 1 h) and stirred for an addition-
al 1 h at ambient temperature. The mixture was filtered and washed with
water (20 mL, 3 times), THF (20 mL, 3 times), and CH2Cl2 (20 mL, 3
times). The residue was dried in vacuo for 18 h to give the polymer-sup-
ported ligand (1). 31P NMR (400 MHz, CDCl3, 258C): d=+19.7.
The loading amount of phosphine was analyzed by ICP-AES. The ligand
(1) (19.7 mg) was treated with HNO3 (20%, 3 mL) at 908C for 21 h and
filtered. The filtrate was filled with pure water up to 50 mL and analyzed
by ICP-AES to determine that the loading value of phosphine was
0.21 mmolgÀ1
.
Preparation of 1-Pd complex (P/Pd=2:1): The polymer-supported ligand
(1) (1.27 g, 0.32 mmol of phosphine residue) was mixed with di(m-
chloro)bis ([PdCl (30.2 mg,
(h3-allyl)dipalladium(II) (h3-C3H5)]2)
0.17 mmol of Pd) in CH2Cl2 (12.7 mL) at ambient temperature and
shaken for 1 h under a nitrogen atmosphere. The mixture was filtered
and the resulting resin beads were washed with CH2Cl2 (12.7 mL, 3
times), dried in vacuo overnight to provide the 1-Pd complex (1.33 g).
31P NMR (400 MHz, CDCl3, 258C): d=+54.4.
[4] For studies on polymer-supported transition metal complex catalysts
from the authorꢂs group, see: a) Y. Uozumi, H. Danjo, T. Hayashi,
lylic substitution); c) Y. Uozumi, H. Danjo, T. Hayashi, J. Org.
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ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Asian J. 2010, 5, 1788 – 1795