N-arylation of heterocycles with chloro- and fluoroarenes using resin-supported sulfonato-Cu(salen) complex

Article abstract of DOI:10.1080/00397910701798218

Sulfonato-Cu(salen) complex immobilized onto a Merrifield's resin was found to be an efficient catalyst for the N-arylation of heterocycles with electron-withdrawing hloro- and fluoroarenes. The reactions were carried out in the presence of an inexpensive mild base, K2CO3, and N-arylated compounds were obtained in good to excellent yields. The catalyst was recovered by simple filtration and reused for three cycles with almost consistent activity. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/00397910701798218

This article was downloaded by: [Istanbul Universitesi Kutuphane ve Dok]
On: 05 June 2013, At: 23:31
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office:
Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Synthetic Communications: An International
Journal for Rapid Communication of
Synthetic Organic Chemistry
Publication details, including instructions for authors and subscription
information:
http://www.tandfonline.com/loi/lsyc20
N‐Arylation of Heterocycles with Chloro‐
and Fluoroarenes using Resin‐Supported
Sulfonato‐Cu(salen) Complex
M. Lakshmi Kantam a , T. Ramani a & L. Chakrapani a
a Inorganic and Physical Chemistry Division, Indian Institute of Chemical
Technology, Hyderabad, India
Published online: 27 Feb 2008.
To cite this article: M. Lakshmi Kantam , T. Ramani & L. Chakrapani (2008): N‐Arylation of Heterocycles with
Chloro‐ and Fluoroarenes using Resin‐Supported Sulfonato‐Cu(salen) Complex, Synthetic Communications: An
International Journal for Rapid Communication of Synthetic Organic Chemistry, 38:4, 626-636
To link to this article: http://dx.doi.org/10.1080/00397910701798218
PLEASE SCROLL DOWN FOR ARTICLE
Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions
This article may be used for research, teaching, and private study purposes. Any substantial
or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or
distribution in any form to anyone is expressly forbidden.
The publisher does not give any warranty express or implied or make any representation that the
contents will be complete or accurate or up to date. The accuracy of any instructions, formulae,
and drug doses should be independently verified with primary sources. The publisher shall not
be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or
howsoever caused arising directly or indirectly in connection with or arising out of the use of this
material.

Synthetic Communicationsw, 38: 626–636, 2008
Copyright # Taylor & Francis Group, LLC
ISSN 0039-7911 print/1532-2432 online
DOI: 10.1080/00397910701798218
N-Arylation of Heterocycles with Chloro-
and Fluoroarenes using Resin-Supported
Sulfonato-Cu(salen) Complex
M. Lakshmi Kantam, T. Ramani, and L. Chakrapani
Inorganic and Physical Chemistry Division, Indian Institute of Chemical
Technology, Hyderabad, India
Abstract: Sulfonato-Cu(salen) complex immobilized onto a Merrifield’s resin was
found to be an efficient catalyst for the N-arylation of heterocycles with electron-
withdrawing chloro- and fluoroarenes. The reactions were carried out in the presence
of an inexpensive mild base, K2CO3, and N-arylated compounds were obtained in
good to excellent yields. The catalyst was recovered by simple filtration and reused
for three cycles with almost consistent activity.
Keywords: heterocycles, Merrifield’s resin, N-arylation, reusability, sulfonato-
Cu(salen) complex
INTRODUCTION
C(aryl)-N bond formation plays an important role in organic synthesis because
the resultant N-arylated products have widespread use in pharmaceutical and
agrochemical industries.[1,2] Traditionally N-arylated heterocycles have been
prepared either by nucleophilic aromatic substitution[3] or by Ullmann-type
coupling reactions.[4] The former method requires substrates bearing electron-
withdrawing substituents (EW), and the latter coupling requires harsh reaction
conditions and the use of stochiometric amounts of copper. Milder methods
involving various arylating agents have also been reported,[5] but only few
Received in India August 22, 2007
Address correspondence to M. Lakshmi Kantam, Inorganic and Physical Chemistry
Division, Indian Institute of Chemical Technology, Hyderabad 500 007, India. E-mail:
mlakshmi@iict.res.in
626

N-Arylation of Heterocycles
627
were with aryl halides as arylating agents.[6] Antilla et al. employed
copper(I)–iodide and trans-N,N-dimethyl-1,2-cyclohexanediamine in the
N-arylation of indoles with bromo- and iodoarenes.[6f] Ma et al.[7] and Deng
et al.[8] reported amino-acid-promoted CuI-catalyzed C-N bond formation of
amines or N-containing heterocycles and sulfonamides with bromo- and iodoar-
enes. Cristau et al. reported N-arylation of azoles using cuprous oxide and oxime
ligandsundermild conditions.[6g] Although considerable advancesintheN-aryla-
tions using copper catalysts have been achieved, generally the coupling partners
of azoles were confined to aryl iodides or aryl bromides. There are only a few
reports of the coupling reaction using aryl chlorides and fluorides as coupling
partners. Copper-oxide-coated copper nanoparticles catalyzed N-arylation of het-
erocycles with chloroarenes containing EW groups and electron-donating groups
(ED) by Pd catalysts in the presence of strong bases are reported.[9] Although C-N
and C-C coupling reactions with fluoroarenes (EW) are realized using Pd(0)
catalysts, the scope is severely restricted to fluoroarenetricarbonylchromium(0)
or 2-nitrofluoroarene only.[10] Most of these methodologies are homogeneous
in nature, where recyclability of the catalyst could not be achieved. Hetero-
geneous catalysis is particularly attractive because it allows the production and
ready separation of large quantities of products with the use of a small amount
of catalyst. Recently, our group reported that copper-basic apatites are
potential catalysts for N-arylation of fluoro and chloroarenes.[11]
Salen ligands are recognized as efficient auxillaries, and many metallosalen
complexes have been found to serve as excellent catalysts for various organic
transformations.[12] Phan et al. reported the Suzuki–Miyaura cross-coupling
reaction using a polymer-supported salen-type palladium complex.[13] Cristau
et al. examined the efficiency of salen ligands in the N-arylation of imidazole
with bromobenzene but the yields were low.[6g] We herein report the
N-arylation of heterocycles with chloro-and fluoroarenes by using recyclable
resin-supported sulfonato-Cu(salen) catalyst in the presence of an inexpensive
and mild base K2CO3 (Scheme 1). The catalyst is recovered after the reaction
by simple filtration and reused for three cycles with consistent activity.
RESULTS AND DISCUSSIONS
The catalysts 1a–f were screened for the N-arylation of imidazole with
1-chloro-4-nitrobenzene, and the catalyst 1f was found to be an efficient one
(Scheme 2).[14] Catalysts 1c–f are more efficient than 1a and 1b because of
Scheme 1. N-Arylation of heterocycles with chloro- and fluoroarenes.

628
M. L. Kantam, T. Ramani, and L. Chakrapani
Scheme 2. Schematic representation of catalysts 1a–f.
the presence of strong EW sulfonated groups at 5,51 positions, which increase
their reactivity.[15] Similarly, catalysts containing trans-cyclohexylamine
ligands 1b, 1d, and 1f were much more efficient (Table 1, entries 2, 4, and
6) than ethylenediamine ligands 1a, 1c, and 1e (Table 1, entries 1, 3, and 5)
in promoting the arylation reaction.[6b,6f]
To identify the best system for N-arylation of imidazole with 1-chloro-4-
nitrobenzene, a variety of bases were screened (Table 2). The organic amine
bases, triethylamine and 1,4,-diazabicyclo [2.2.2]octane (DABCO) (Table 2,
entries 5 and 6), gave no arylated product. The stronger inorganic bases
(Table 2, entries 1–4) all resulted in high conversions. Though Cs2CO3 and
Table 1. Screening of catalysts for the N-arylation of imidazole
with 1-chloro-4-nitrobenzenea
Entry
Catalyst
Yield (%)b
1
2
3
4
5
6
1a
1b
1c
1d
1e
1f
5
12
30
62
55
95
aReaction conditions: catalyst (1 mol%), ArCl (1 mmol),
imidazole (1.2 mmol), K2CO3 (2 mmol), DMF (3 mL), 1108C, 2 h.
bIsolated yields.

N-Arylation of Heterocycles
629
Table 2. N-Arylation of imidazole with 1-chloro-4-nitrobenzene
using a series of basesa
Entry
Base
Yield (%)b
1
2
3
4
5
K2CO3
Cs2CO3
K3PO4
t-BuOK
Et3N
95
99
90
99
0
aReaction conditions: catalyst 1f (1 mol%), ArCl (1 mmol),
imidazole (1.2 mmol), base (2 mmol), DMF (3 mL), 1108C, 2 h.
bIsolated yields.
t-BuOK gave excellent yields, K2CO3, an inexpensive mild base, was used in
this study.
We have screened the influence of different solvents in the N-arylation of
imidazole with 1-chloro-4-nitrobenzene (Table 3). N,N-dimethylformamide
(DMF) and dimethylsulfoxide (DMSO) gave the best results (Table 3,
entries 1 and 2), N-methyl-2-pyrrolidone (NMP) gave slightly lower yield
(Table 3, entry 3), and poor yields were obtained in toluene and acetonitrile
(Table 3, entries 4 and 5). In water and methanol, no product was formed
(Table 3, entries 6 and 7). These results indicate that N-heterocycles can be
prepared in the presence of cheap and mild base K2CO3 in DMF solvent.
Table 3. Influence of solvent in the N-arylation of imidazole with 1-chloro-4-
nitrobenzenea
Entry
Solvent
T (8C)
Yield (%)b
1
2
3
4
5
6
7
DMF
110
120
110
120
82
95
85
20
80
5
DMSO
Toluene
NMP
MeCN
Water
MeOH
100
65
0
0
aReaction conditions: catalyst 1f (1 mol%), ArCl (1 mmol), imidazole (1.2 mmol),
K2CO3 (2 mmol), 2 h.
bIsolated yields.

630
M. L. Kantam, T. Ramani, and L. Chakrapani
Scheme 3. Schematic representation of resin-supported 1f preparation.
The Merrifield resin-supported catalyst 1f was prepared according to the
procedure reported previously (Scheme 3).[11] The Cu content was found to be
21
0.1 mmol g by atomic absorption spectroscopy (AAS).
.
After optimizing the reaction conditions, the reaction scope was
extended with various aryl halides and azoles. We chose a variety of sub-
stituted chloro-and fluoroarenes possessing a wide range of functional
Table 4. N-Arylation of imidazole with chloroarenes
Homogeneousa
Heterogeneousc
Entry
Ar-Cl
Time (h)
Yield (%)b
Time (h)
Yield (%)d
1
2
1.5
3
94
91
4
5
91 (87)a
90
3
4
6
5
90
88
12
12
87
85
5
2
95
5
92
6
7
10
7
88
92
16
12
85
90
8
5
88
10
85
9
1
87
0
3
85
0
10
24
48
aReaction conditions: catalyst 1f (1 mol%), ArX (1 mmol), imidazole (1.2 mmol),
K2CO3 (2 mmol), DMF (3 mL), 1108C.
bIsolated yields.
cReaction conditions: catalyst resin 1f (1 mol%), ArX (1 mmol), imidazole
(1.2 mmol), K2CO3 (2 mmol), DMF (4 mL), 1108C.
dYield after third cycle.

N-Arylation of Heterocycles
631
Table 5. N-Arylation of imidazole using different fluoroarenes
Homogeneousa
Heterogeneousc
Entry
Ar-X
Time (h)
Yield (%)b
Time (h)
Yield (%)b
1
2
1
95
93
3
4
92
90
1.5
3
4
1
96
92
2.5
3
91
90
1.5
5
6
1.5
1.5
93
92
3
3
91
90
aReaction conditions: catalyst 1f (1 mol%), ArF (1 mmol), imidazole (1.2 mmol),
K2CO3 (2 mmol), DMF (3 mL), 1108C.
bIsolated yields.
cReaction conditions: catalyst resin 1f (1 mol%), ArF (1 mmol), imidazole
(1.2 mmol), K2CO3 (2 mmol), DMF (4 mL), 1108C.
Table 6. N-Arylation of various nitrogen heterocyclesa
X ¼ F
Yield (%)b
X ¼ Cl
Yield (%)b
Entry
1
Het-NH
Time (h)
1 (3)c
Time (h)
3 (7)
92 (85)
90 (87)
2
1.5 (4)
90 (82)
4 (10)
87 (80)
3
4
5 (12)
1 (3)
85 (80)
90 (87)
10 (18)
5 (12)
85 (82)
87 (83)
aReaction conditions: catalyst 1f (1 mol%) or catalyst resin 1f (1 mol%), ArX
(1 mmol), Het-NH (1.2 mmol), K2CO3 (2 mmol), DMF (3 mL), 1108C.
bIsolated yields.
cValues in parentheses correspond to the heterogeneous catalyst.

632
M. L. Kantam, T. Ramani, and L. Chakrapani
groups for our study. As illustrated in Table 4, when o- and p-chloro-
nitrobenzenes were used, the corresponding N-arylated products were
obtained in excellent yields (entries 1 and 2). Cyano, nitro, and aldehyde
groups are well tolerated. 2-Chloropyridine and 2-chloropyrimidine also
provided excellent yields as can be seen from Table 4 (entries 7 and 9).
The sterically bulky 4-chlorobenzophenone was converted to the corre-
sponding N-arylated product (entry 8) with excellent yields. In the case
of unactivated chloroarene such as chlorobenzene, this catalytic system is
completely inactive (entry 10).
Particularly noteworthy is that fluoroarenes composed of several o- or
p-EW groups are also coupled with imidazole to afford the corresponding
N-arylated products in excellent yields. Faster reactivity over the chloroarenes
(Tables 4 and 5) and selective coupling involving C-F activation only in
chlorofluoroarene (Table 5, entry 6) are other attributes of this coupling
reaction.
As can be seen from Table 6, other nitrogen-containing heterocycles,
such as pyrrole, pyrazole, benzimidazole, and piperidine, gave the corre-
sponding N-arylated products with 1-chloro-4-nitrobenzene and 1-fluoro-
4-nitrobenzene in excellent yields. We observed lower reaction rates
with resin-supported 1f compared to its homogeneous counterpart, but
comparable yields were obtained. The resin supported 1f can be
recovered by simple filtration and reused for three cycles with consistent
activity.
CONCLUSION
In conclusion, the resin-supported sulfonato-Cu(salen) complex was found
to be an efficient and reusable catalyst for the N-arylation of hetero-
cycles with both EW chloro- and fluoroarenes using K2CO3 as base.
The resin catalyst was reused for three cycles with almost consistent
activity.
EXPERIMENTAL
Synthesis of Catalyst 1f
A mixture of disodium 3-tert-butyl-salicylaldehyde 5-sulfonate[11] (0.600 g,
2 mmol) and trans-1,2-diaminocyclohexane (0.114 g, 1 mmol) in methanol
(50 mL) was stirred at room temperature for 17 h. To this reaction mixture,
.
Cu(OAc)2 H2O (0.200 g, 1 mmol) was added, and the mixture was stirred
at reflux temperature for 12 h. Then the reaction mixture was filtered, and
the precipitate was washed with dichloromethane (50 mL) to remove
.
unreacted Cu(OAc)2 H2O. Thereafter, the solid was collected and dried

N-Arylation of Heterocycles
633
under vacuum to afford the catalyst 1f (yield 80%). ESI-MS (negative): m/z
654 [M 2 2Na]2; IR (KBr) 3454, 2941, 1636, 1602, 1532, 1114, 1037,
836 cm21
.
Typical Experimental Procedure of N-Arylation Under
Homogeneous Conditions
Catalyst 1f (0.007 g, 1 mol%), K2CO3 (0.276 g, 2 mmol) were added to a
mixture of 1-chloro-4-nitrobenzene (0.158 g, 1 mmol) and imidazole
(0.081 g, 1.2 mmol) in 3 mL of DMF. The reaction mixture was heated at
1108C under stirring for 1.5 h. After cooling to ambient temperature, the
resulting mixture was added with 4 mL of ethyl acetate and 10 mL of
water. The organic layer was separated, and the aqueous layer was further
extracted with ethyl acetate (10 mL). The combined organic phase was
washed with brine and dried over Na2SO4. The solvent was removed under
vacuum, and the residue was further purified by flash-column chromatography
on silica gel to afford the product 1-(4-nitrophenyl)-1H-imidazole in 94%
yield.
Typical Experimental Procedure of N-Arylation under
Heterogeneous Conditions
Catalyst 1f (0.050 g, 1 mol%) and K2CO3 (0.276 g, 2 mmol) were added to a
mixture of 1-chloro-4-nitrobenzene (0.158 g, 1 mmol) and imidazole (0.081 g,
1.2 mmol) in 4 mL of DMF. The reaction mixture was heated at 1108C under
stirring for 4 h. After cooling to ambient temperature, the resulting mixture
was filtered off, and the catalyst was washed several times with water and
ethyl acetate to remove any excess reagents and reused for the other cycle.
The filtrate was extracted with water, and the organic layer was dried over
Na2SO4. This was concentrated under vacuum, and the residue was purified
by column chromatography on silica gel to afford the product 1-(4-nitro-
phenyl)-1H-imidazole in 91% yield.
1-(4-Nitrophenyl)-1H-imidazole
Mp 2038C; 1H NMR (300 MHz, CDCl3) d 8.37 (d, J ¼ 9.0 Hz, 2H), 7.93 (br s,
1H), 7.58 (d, J ¼ 9.0 Hz, 2H), 7.32 (br s, 1H), 7.24 (br s, 1H); EI-MS: 189
(100%), 159, 141, 116, 89, 50; HRMS m/z 189.053 (calcd, for C9H7N3O2:
189.053); IR (KBr): 3130.96, 1599.57, 1528.72, 1340.33, 1052.66,
854.85 cm21
.

634
M. L. Kantam, T. Ramani, and L. Chakrapani
ACKNOWLEDGMENTS
We thank the CSIR for financial support under the Task Force Project
CMM-0005. T. Ramani thanks the University Grants Commission (UGC),
and L. C. thanks the Council of Scientific and Industrial Research (CSIR),
India, for providing senior research fellowships.
REFERENCES
1. (a) Ley, S. V.; Thomas, A. W. Modern synthetic methods for copper-mediated C
(aryl)-O, C (aryl)-N, and C (aryl)-S bond formation. Angew. Chem. Int. Ed. 2003,
42, 5400–5449; (b) Negwer, W. Organic Drugs and Their Synonyms: An Inter-
national Survey, 7th edn.; Akademie Verlag GmbH: Berlin, 1994;
(c) Martinez, G. R.; Walker, K. A. M.; Hirschfield, D. R.; Bruno, J. J.; Yang, D. S.;
Moloney, P. J. 3,4-Dihydroquinolin-2(1H)-ones as combined inhibitors of thrombox-
ane A2 synthase and cAMP phosphodiesterase. J. Med. Chem. 1992, 35, 620–628.
2. (a) Lopez-Alvarado, P.; Avendano, C.; Menendez, J. C. New synthetic appli-
cations of aryllead triacetates: N-Arylation of amides. J. Org. Chem. 1996, 61,
5865–5870; (b) Lee, H. M.; Nolan, S. P. Efficient cross-coupling reactions of
aryl chlorides and bromides with phenyl- or vinyltrimethoxysilane mediated by
a palladium/imidazolium chloride system. Org. Lett. 2000, 2, 2053–2055;
(c) Herrman, W. A.; Kocher, C. N-Heterocyclic carbenes. Angew. Chem. Int.
Ed. 1997, 36, 2162–2187.
3. (a) Ohmori, J.; Shimizu-Sasamata, M.; Okada, M.; Sakamoto, S. Novel AMPA
receptor antagonists: synthesis and structure–activity relationships of
1-hydroxy-7-(1-H-imidazol-1-yl)-6-nitro-2,3(1H,4H)-quinoxalinedione
and
related compounds. J. Med. Chem. 1996, 39, 3971–3979; (b) Antonini, I.;
Cristalli, G.; Franchetti, P.; Grifantini, M.; Martelli, S. Nickel complex-
catalyzed methyl ketone synthesis via carbonylation of organic halides with tetra-
methyltin. Synthesis 1983, 47–48.
4. (a) Lindley, J. Copper-assisted nucleophilic substitution of aryl halogen. Tetrahe-
dron 1984, 40, 1433–1456; (b) Kiyomori, A.; Marcoux, J. F.; Buchwald, S. L. An
efficient copper-catalyzed coupling of aryl halides with imidazoles. Tetrahedron
Lett. 1999, 40, 2657–2660; (c) Hassan, J.; Sevignon, M.; Gozzi, C.; Schulz, E.;
Lemaire, M. Aryl-aryl bond formation one century after the discovery of the
Ullmann reaction. Chem. Rev. 2002, 102, 1359–1469.
5. (a) Elliott, G. I.; Konopelski, J. P. Complete N-1 regiocontrol in the formation of
N-arylimidazoles: synthesis of the active site His-Tyr side chain coupled dipeptide
of cytochrome c oxidase. Org. Lett. 2000, 2, 3055–3057; (b) Lam, P. Y. S.;
Clark, C. G.; Saubern, S.; Adams, J.; Winters, M. P.; Chan, D. M. T.;
Combs, A. New aryl/heteroaryl C-N bond cross-coupling reactions via arylboro-
nic acid/cupric acetate arylation. Tetrahedron Lett. 1998, 39, 2941–2944;
(c) Mederski, W. W. K. R.; Lefort, M.; Germann, M.; Kux, D. Tetrahedron
1999, 55, 12757–12770; (d) Collman, J. P.; Zhong, M. An efficient diamine-
copper complex–catalyzed coupling of arylboronic acids with imidazoles. Org.
Lett. 2000, 2, 1233–1236; (e) Lam, P. Y. S.; Deudon, S.; Averill, K. M.; Li, R.;
He, M. Y.; DeShong, P.; Clark, C. G. Copper-promoted C-N bond cross-

N-Arylation of Heterocycles
635
coupling with hypervalent aryl siloxanes and room-temperature N-arylation with
aryl iodide. J. Am. Chem. Soc. 2000, 122, 7600–7601.
6. (a) Gujadhur, R. K.; Bates, C. G.; Venkataraman, D. Formation of aryl-nitrogen,
aryl-oxygen, and aryl-carbon bonds using well-defined copper(I)-based catalysts.
Org. Lett. 2001, 3, 4315–4317; (b) Klapars, A.; Huang, X.; Buchwald, S. L. A
general and efficient copper catalyst for the amidation of aryl halides. J. Am.
Chem. Soc. 2002, 124, 7421–7428; (c) Klapars, A.; Antilla, J. C.; Huang, X.;
Buchwald, S. L. A general and efficient copper catalyst for the amidation of aryl
halides and the N-arylation of nitrogen heterocycles. J. Am. Chem. Soc. 2001,
123, 7727–7729; (d) Antilla, J. C.; Klapars, A.; Buchwald, S. L. The copper-
catalyzed N-arylation of indoles. J. Am. Chem. Soc. 2002, 124, 11684–11688;
(e) Klapars, A.; Parris, S.; Anderson, K. W.; Buchwald, S. L. Synthesis of
medium ring nitrogen heterocycles via a tandem copper-catalyzed C-N bond
formation–ringexpansion process. J. Am. Chem. Soc. 2004, 126, 3529–3533;
(f) Antilla, J. C.; Baskin, J. M.; Barder, T. E.; Buchwald, S. L. Copper-diamine-
catalyzed N-arylation of pyrroles, pyrazoles, indazoles, imidazoles, and
triazoles. J. Org. Chem. 2004, 69, 5578–5587; (g) Cristau, H.-J.; Cellier, P. P.;
Spindler, J.-F.; Taillefer, M. Highly efficient and mild copper-catalyzed N- and
C-arylations with aryl bromides and iodides. Chem. Eur. J. 2004, 10, 5607–5622.
7. (a) Ma, D.; Zhang, Y.; Yao, J.; Wu, S.; Tao, F. Accelerating effect induced by the
structure of a-amino acid in the copper-catalyzed coupling reaction of aryl halides
with a-amino acids: synthesis of benzolactam-V8. J. Am. Chem. Soc. 1998, 120,
12459–12467; (b) Ma, D.; Xia, C. CuI-catalyzed coupling reaction of b-amino
acids or esters with aryl halides at temperature lower than that employed in the
normal Ullmann reaction: facile synthesis of SB-214857. Org. Lett. 2001, 3,
2583–2586; (c) Ma, D.; Xia, C.; Jiang, J.; Zhang, J.; Tang, W. Aromatic nucleo-
philic substitution or CuI-catalyzed coupling route to martinellic acid. J. Org.
Chem. 2003, 68, 442–451; (d) Ma, D.; Cai, Q.; Zhang, H. Mild method for
Ullmann coupling reaction of amines and aryl halides. Org. Lett. 2003, 5,
2453–2455; (e) Ma, D.; Cai, Q. N,N-Dimethyl glycine-promoted Ullmann
coupling reaction of phenols and aryl halides. Org. Lett. 2003, 5, 3799–3802;
(f) Pan, X.; Cai, Q.; Ma, D. CuI/N,N-dimethylglycine-catalyzed coupling of
vinyl halides with amides or carbamates. Org. Lett. 2004, 6, 1809–1812;
(h) Ma, D.; Liu, F. CuI-catalyzed coupling reaction of aryl halides with terminal
alkynes in the absence of palladium and phosphine. Chem. Commun. 2004,
1934–1935; (i) Zhu, W.; Ma, D. Synthesis of aryl azides and vinyl azides via
proline-promoted CuI-catalyzed coupling reactions. Chem. Commun. 2004,
888–889; (j) Zhu, W.; Ma, D. Synthesis of aryl sulfones via L-proline-promoted
cui-catalyzed coupling reaction of aryl halides with sulfinic acid salts. J. Org.
Chem. 2005, 70, 2696–2700; (k) Zhang, H.; Cai, Q.; Ma, D. Amino acid
promoted CuI-catalyzed C-N bond formation between aryl halides and amines
or N-containing heterocycles. J. Org. Chem. 2005, 70, 5164–5173; (l) Cai, Q.;
Zhu, W.; Zhang, H.; Zhang, Y.; Ma, D. Preparation of N-aryl compounds by
amino acid–promoted Ullmann-type coupling reactions. Synthesis 2005,
496–499.
8. (a) Deng, W.; Zou, Y.; Wang, Y.-F.; Liu, L.; Guo, Q.-X. CuI-catalyzed coupling
reactions of aryl iodides and bromides with thiols promoted by amino acid ligands.
Synlett 2004, 1254–1258; (b) Deng, W.; Wang, Y.-F.; Zou, Y.; Liu, L.; Guo, Q.-X.
Amino acid–mediated Goldberg reactions between amides and aryl iodides. Tetra-
hedron Lett. 2004, 45, 2311–2315.

636
M. L. Kantam, T. Ramani, and L. Chakrapani
9. (a) Son, S. U.; Park, I. K.; Park, J.; Hyeon, T. Synthesis of Cu2O-coated Cu nano-
particles and their successful applications to Ullmann-type amination coupling
reactions of aryl chlorides. Chem. Commun. 2004, 778–779; (b) Amrani, R. O.;
Schneider, R.; Fort, Y. Novel synthetic strategy of N-arylated heterocycles via
sequential palladium-catalyzed intra- and inter-arylamination reactions.
Synthesis 2004, 15, 2527–2534.
10. (a) Kim, Y. M.; Yu, S. Palladium(0)-catalyzed amination, Stille coupling, and
Suzuki coupling of electron-deficient aryl fluorides. J. Am. Chem. Soc. 2003,
125, 1696–1697; (b) Widdowson, D. A.; Wilhelm, R. Palladium-catalyzed
Suzuki reactions of fluoroarenes. Chem. Commun. 2003, 578–579;
(c) Widdowson, D. A.; Wilhelm, R. Palladium-catalyzed cross-coupling of (fluor-
oarene) tricarbonyl chromium(0) complexes. Chem. Commun. 1999, 2211–2212;
(d) Wilhelm, R.; Widdowson, D. A. Palladium catalyzed cross-coupling of (fluoro-
arene) tricarbonylchromimum(O) complexes. J. Chem. Soc., Perkin Trans. 1 2000,
22, 3808–3813.
11. Choudary, B. M.; Sridhar, C.; Kantham, M. L.; Venkanna, G. T.; Sreedhar, B.
Design and evolution of copper apatite catalysts for N-arylation of heterocycles
with chloro- and fluoroarenes. J. Am. Chem. Soc. 2005, 127, 9948–9949.
12. Larrow, J. F.; Jacobsen, E. N. Asymmetric processes catalyzed by chiral (salen)
metal complexes. Topics Organomet. Chem. 2004, 6, 123–152.
13. (a) Phan, N. T. S.; Brown, D. H.; Styring, P. A poymer-supported salen-type
palladium complex as a catalyst for the Suzuki–Miyaura cross-coupling
reaction. Tetrahedron Lett. 2004, 45, 7915–7919; (b) Phan, N. T. S.; Khan, J.;
Styring, P. Polymer-supported palladium catalyzed Suzuki–Miyaura reactions in
batch and a mini-continuous flow reactor system. Tetrahedron 2005, 61,
12065–12073.
14. (a) Berry, K. J.; Moya, F.; Murray, K. S.; Bergen, A. M. B. V.; West, B. O. Water-
soluble cobalt(II) complexes of NN0-substituted bis(salicylaldimine-5-sulfonic
acids): oxygen-carrying properties and conversion into cobalt (III) organometallic
compounds. J. Chem. Soc., Dalton. Trans. 1982, 109–116; (b) Chen, D.;
Martell, A. E.; Sun, Y. New synthetic cobalt Schiff base complexes as oxygen
carriers. Inorg. Chem. 1989, 2647–2652.
15. (a) Srinivasan, K.; Michaud, P.; Kochi, J. K. Epoxidation of olefins with cationic
(salen)manganese(III) complexes: the modulation of catalytic activity by substitu-
ents. J. Am. Chem. Soc. 1986, 108, 2309–2320; (b) Silva, A. R.; Freire, C.;
Castro, B. Modulation of the catalytic activity of manganese(III) salen
complexes in the epoxidation of styrene: influence of the oxygen source. New.
J. Chem. 2004, 253–260.