Cp*Co(iii) and Cu(OAc)2bimetallic catalysis for Buchwald-type C-N cross coupling of aryl chlorides and amines under base, inert gas & solvent-free conditions

Article abstract of DOI:10.1039/d0gc02819c

A strategy involving bimetallic catalysis with a combination of Cp?Co(CO)I2 and Cu(OAc)2 was used for performing Buchwald-type C-N coupling reactions of aryl chlorides with amines. The reactions proceeded at 100 °C to produce excellent yields of many of the desired C-N coupled products, in 4 h, under aerobic reaction conditions. The reactions were shown to run under base-free and solvent-free conditions, enabling this strategy to work efficiently for electron-withdrawing and base-sensitive functionalities. The presented methodology was found to be equally efficient for electron-donating functionalities as well as for primary (1°) and secondary (2°) aromatic and aliphatic amines. Moreover, the products were easily separated through the extractions of the organic aqueous layer, with this process chromatographic separations is not required.

Full text of DOI:10.1039/d0gc02819c

View Article Online
View Journal
Green
Chemistry
Cutting-edge research for a greener sustainable future
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: A. K. Srivastava, C.
Sharma and R. K. Joshi, Green Chem., 2020, DOI: 10.1039/D0GC02819C.
Volume 20
This is an Accepted Manuscript, which has been through the
Number
May 2018
Pages 1919-2160
9
7
Royal Society of Chemistry peer review process and has been
accepted for publication.
Green
Chemistry
Cutting-edge research for a greener sustainable future
rsc.li/greenchem
Accepted Manuscripts are published online shortly after acceptance,
before technical editing, formatting and proof reading. Using this free
service, authors can make their results available to the community, in
citable form, before we publish the edited article. We will replace this
Accepted Manuscript with the edited and formatted Advance Article as
soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes to the
text and/or graphics, which may alter content. The journal’s standard
Terms & Conditions and the Ethical guidelines still apply. In no event
shall the Royal Society of Chemistry be held responsible for any errors
or omissions in this Accepted Manuscript or any consequences arising
from the use of any information it contains.
ISSN 1463-9262
PAPER
Paul T. Anastas et al.
The Green ChemisTREE: 20 years after taking root with the 12
principles
rsc.li/greenchem

Please do not adjust margins
Page 1 of 6
Green Chemistry
View Article Online
DOI: 10.1039/D0GC02819C
COMMUNICATION
Cp*Co(III) and Cu(OAc)2 Bimetallic Catalyst for Buchwald type C-N
Cross Coupling of Arylchlorides and Amines under Base, Inert gas
& Solvent-free Conditions
Received 00th January 20xx,
Accepted 00th January 20xx
Avinash K. Srivastava, Charu Sharma, Raj K. Joshi*
DOI: 10.1039/x0xx00000x
This article is dedicated to the 65th birth anniversary of Professor Pradeep Mathur, IIT Bombay, India.
A bimetallic catalytic strategy in the combination of Cp*Co(CO)I2 The single-site approaches include the Buchwald-Hartwig
and Cu(OAc)2 is used for Buchwald type C-N coupling reaction of coupling11 with Pd metal, and various other metal-based
aryl chlorides and amines. The reaction works at 100 °C to produce approaches have been employed for C-N coupling reactions.8
an excellent yield of the desired C-N coupling product, in 4 h, Apart from that, a variety of Cu compounds has been used for
under aerobic reaction conditions. The reactions run under base the Ullmann type coupling reactions.12 However, most of the
free and solvent-free conditions, which enables this strategy to reactions, utilise strong base, most commonly tBuONa or
work efficiently for electron-withdrawing and base sensitive tBuOK and organic solvents. The use of a strong base in a polar
functionalities. The presented methodology is found to be equally aprotic or non-polar solvent is not advisable due to their low
efficient for electron-donating functionalities as well as for the solubility, which directly increases the time of reaction. Also,
primary 1° and 2° aromatic and aliphatic amines. Moreover, the the use of a strong base with aryl halides leads to the
products can be easily separated through the extractions of the formation of Na or K salts as a by-product.13 The low solubility
organic aqueous layer, and this process does not demand of Na or K salts triggers the precipitation, hence, discouraged
chromatographic separations.
to use in flow reactors for bulk synthesis.13 Furthermore, the
use of a strong base in the reaction restricts its application
towards base sensitive functionalities. The Ullmann type C-N
coupling reactions, are considered as an economical alternate
but, the stoichiometric amounts of Cu, long reaction time, high
temperature, presence of a base and limited substrate scope
are some of the associated drawbacks.7 Scheme 1 shows the
earlier methods of amination, the classical methodologies are
multistep and less efficient, Ullman and Chan-Lam coupling
reaction require a long time,14 while the Buchwald-Hartwig
coupling is the latest upgrade in this series, which need Pd
catalyst, base and solvent.7,15 Metal carbonyl complexes are
well-known for various catalytic reactions.16-18 The high valent
[Cp*Co(CO)I2] complex is well established19 for C-C coupling
reactions via C-H activation.20-21 In recent, Matsunaga and co-
workers used Cp*Co(III) for amidations of thioamide,21
moreover, the o-amidations of benzaldehyde has also been
reported by Sundararaju and co-workers.22
Herein, we report Cp*Co(CO)I2 and Cu(OAc)2 as an efficient
bimetallic catalyst for Buchwald type C-N reaction. The
method works under the aerobic, solvent and base free
condition to produces exceptional yields in just 4h. Moreover,
the method is also found suitable for base sensitive functional
groups and show wide functional group tolerance. To the best
of our knowledge, this the first report where the Cp*Co(III) has
been exploited for the CN bond formation between aryl
chloride and amines.
3d-Transition metal catalysts have produced vast opportunities
to perform commercially important reactions economically. In
recent years, the non-noble metals such as cobalt and copper
had marked their presence in catalysis through their
applications in various catalytic reactions.1-3 Since the
pioneering work of Ullmann4a, 1901 and Kharasch4b, 1941
using Cu and Co catalysed aryl homocoupling reactions, these
metals had received remarkable attention for various coupling
reactions. Moreover, the increasingly attractive, distinctive
catalytic and additionally being inexpensive due to abundance
makes these elements more desirable alternative over the
precious metal catalysts.
Presence of heteroatom and strategic position of a carbon-
heteroatom bond is quite crucial to enhance the activity and
various other applications.5 The year 2019 is the silver jubilee
of the Buchwald-Hartwig coupling reaction, indeed, it is one of
the outstanding discovery which enables us to synthesize a
large variety of C-N coupling products with ease from last two
decades.6-9 Recently, the bimetallic catalytic strategies became
an alternate paradigm to perform C-C coupling reactions.10
But, the bimetallic strategies are rarely known for the
heteroatom cross-coupling reactions like C-N bond formations.
a. Department of Chemistry, Malaviya National Institute of Technology, Jaipur –
302017, Rajasthan, INDIA. Email: rkjoshi.chy@mnit.ac.in
† Footnotes relating to the title and/or authors should appear here.
Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI: 10.1039/x0xx00000x
Please do not adjust margins

Please do not adjust margins
Green Chemistry
Page 2 of 6
COMMUNICATION
Journal Name
R1
H
Cu + Base
X
N
R
+
Ullman Coupling
Ar
Ar
Ar
X = Br, I
View Article Online
DOI: 10.1039/D0GC02819C
Aromatic Nucleophilic
Substitiution (SnAr)
R1
H
Ar
R1
Cu + Base
Chan-Evans-Lam
Coupling
B(OH)2
N
R
N
R
+
Multistep Process
1. Nitration
2. NO2 Reduction
3. Alkylation or Arylation
R1
H
Pd + Base
Buchwald - Hartwig
Coupling
X
N
R
+
X = Cl, Br, I
Classical Methadologies
Catalytic Methodologies
Scheme 1. Previous methodologies for C-N coupling reactions
Present work
The performing reaction at low temperature acutely affects
the product yield. Dropping the reaction temperature to 80 °C
in a duration of 4 h reduces the product yield to 55% (Table 1,
Entry 14). While further reducing the reaction temperature to
60 °C, drops down the product yield close to the 1/3rd of the
actually obtained yield (Table 1, Entry 13). No product
formations were detected when the reaction was performed
at room temperature (Table 1, Entry 12). While optimizing the
R1
N
Cp*Co(CO)I2 (1 mol%)
Cu(OAc)2 (10 mol%)
Cl
R1
R
N
H
+
R
100 oC, 4h
R1 - H, Aliphatic
R - Aliphatic, Aromatic
Scheme 2. Co and Cu co-catalysed C-N coupling reaction
In 2008 Lipshutz et al., used Ni/Cu@C with tert-BuOLi as a reaction time, it was experienced that a traceable quantity of
heterogeneous bimetallic catalyst at 200 °C for C-N coupling product was formed in the initial hour of the reaction which
reactions.23 Recently we had also reported a pyrazolated keeps on increasing gradually in subsequent hours.
chalcogenide (η5-Cp*)Rh(III) catalyst for the base and solvent-
free C-N coupling under aerobic conditions.24 Despite of
exceptional catalytic activity of the complex, Rh is an
expensive metal. Hence, to find an alternate, an experiment
was executed with chlorobenzene and pyrrolidine in presence
of Cp*Co(CO)I2 and Cu(OAc)2 at 100 °C for 6 h in solvent and
base free conditions. The initial reaction worked very well and
resulted in 92% yield of desired C-N coupling product (Scheme
2). To explore the necessary insights of the reaction, the
mixture of pyrrolidine and chlorobenzene was heated with a
10 mol% of Cu(OAc)2 and in absence of Cp*Co(III), the yield of
desire product was drastically reduced and it took more than
36h to give 38% transformations (Table 1, Entry 1). In contrast,
the Cp*Co(III) failed to mimic the reaction in the absence of
Cu(OAc)2 (Table 1, Entry 2). The reaction produces a maximum
transformation (93%) when a mixture of Cp*Co(III) (1 mol%)
catalyst and Cu(OAc)2 (10 mol%) was considered (Table 1,
Entry 3). Reducing the quantity of Cu(OAc)2 significantly
reduced the present transformation, as 54, 38 and 31%
coupling product was obtained with 5, 2 and 1 mol% of
Cu(OAc)2 respectively, (Table 1, Entry 4-6). Moreover, reducing
the quantity of the Cp*Co(CO)I2 from 1 mol% to 0.25 mol%
severely affects the yield of the product (Table 1, Entry 7 and
8). The continuous reaction monitoring up to 24 h at 0.5 mol%
and 0.25 mol% catalyst loading shows the average yield of 45%
and 38% respectively, the prolong heating also failed to scale
up the transformations and resulted in the decomposition of
catalyst. Further optimisation of the identified reaction
encompasses the scope of other Copper salts, CuCl2, CuSO4
and CuI but, no catalytic activity was detected (Table 1, Entry
9-11). During the temperature optimizations, 100 °C was found
to be efficient for the reaction, hence, most of the reactions
were performed at 100 °C.
Table 1. Optimisation of various reactions parameters
Co(III) Cat.
mol%
--
Cu(OAc)2 Temp Time Yielda
S.No
mol%
10
[°C]
100
100
100
100
100
100
100
100
100
100
100
RT
[h]
36
24
4
%
36
--
1.
2.
1
--
3.
1
10
1b
93
31
38
54
45
38
--
4.
1
4
5.
1
2
4
6.
1
0.5b
0.25b
5
4
7.
10
24
24
8
8.
10
10 (CuCl2)
10 (CuSO4)
10 (CuI)
10
9.
1
1
1
1
1
1
1
1
1
10.
11.
12.
13.
14.
15.
16.
17.
8
--
8
--
12
4
--
10
60
28
55
20
48
76
10
80
4
10
100
100
100
1
10
2
10
3
aIsolated Yields, bgram scale reaction, Pyrrolidine (1mmol),
Chlorobenzene (1mmol)
Using the optimized conditions, the substrate scope of the
reaction was explored, it was started with aliphatic amines
(Table 2, 1a – 1k) which includes cyclic aliphatic amines,
aliphatic primary and secondary amines. In general, the
significant transformation was observed with the electron-
withdrawing functionalities as compared to donor groups. The
presence of withdrawing group at the ortho- position shows a
slight decrease in the product yield.
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
Page 3 of 6
Green Chemistry
Journal Name
COMMUNICATION
Table 2. Substrate Scope of reaction aliphatic amines and triflouromethyl and para-cyano-chlorobenzenesViwewitAhrticbleeOnnzlinyel
DOI: 10.1039/D0GC02819C
arylchlorides
amine yields of 86% (2b), 90% (2c) and 89% (2d), respectively.
A slightly decreased yield was recorded when benzyl amine
was reacted with para-methylchlorobenzene, it produces 83%
(2e) yield of the desired product. The further loss in the
transformation was observed during the reaction of 2-
nitrochlorobenzene and benzylamine, 69% (2f), presumably
steric hindrances and electronic interactions are the possible
factors. Furthermore, heterocyclic substrates were also
explored and the significant transformation was obtained, the
2-chloropyridine reacts well with benzyl amine to yield 77%
(2g) of the product. The Para-methyl substitution over
benzylamine shows a slightly less transformation 73% (2i),
while, an appreciable transformation of 76% (2h) was recorded
for para-nitrochlorobenzene and 2-chloropyridine coupling
product.
Cp*Co(CO)I2 (1 mol%)
Cu(OAc)2 (10 mol%)
R1
N
Cl
R1
R
N
H
+
R
R
100 oC, 4h
R
R = EWG, Me
R1 - H, Aliphatic
R - Aliphatic
N
N
N
F3C
O2N
1a, 91%
1b, 82%
1c, 87%
NO2
N
N
N
O2N
F3C
1d, 83%
1e, 89%
1f, 80%
NO2
N
Table 3. Scope of reaction for benzylamine and arylchlorides
N
N
Cp*Co(CO)I2(1 mol%)
Cu(OAc)2 (10 mol%)
X
Cl
R
NH2
R1
+
R
N
100 oC, 4 h
X
R1
H
R = EWG, p-Me
X = CH, N
R1 = H, Me
1g, 82%
1h, 75%
1i, 67%
H
N
H
H
H
N
Ph
N
Ph
N
Ph
N
O2N
F3C
NC
O2N
2a, 89%
2b, 86%
2c, 90%
1j, 78%
1k, 71%
H
N
NO2
H
Reaction conditions: Amines (1mmol), Arylcholoride (1mmol),
H
Ph
N
Ph
N
Ph
Cp*Co(CO)I2 (1 mol%), Cu(OAc)2 (10 mol%), 100 °C, 4 h.
CN
The very first reaction while exploring the substrate scope was
the chlorobenzene and pyrrolidine which exceptionally yields
91% (1a). The coupling of para-nitrochlorobenzene and para-
triflouromethylchlorobenzene with pyrrolidine shows the
sizeable transformation of 82% (1b) and 87% (1c) respectively.
Similar reactions when repeated with piperidine produces the
desire products with the marginal deviation compared to
pyrrolidine, 83% (1d) and 89% (1e) yields were recorded
respectively. The substantial transformation was observed
with the ortho- substitutions. The reactions of 2-
nitrochlorobenzene with pyrrolidine and piperidine yields 80%
(1f) and 82% (1g) coupling products. Further reactions of para-
and meta- substitutions of methylchlorobenzene and
pyrrolidine show a slight decrease in the yield. The para-
methylchlorobenzene produces 75% (1h) yield, while reaction
with 3-methylchlorobenzene shows further decrease and 67%
(1i) of the desired transformation was obtained. Apart from
that, reactions with diethylamine (a non-cyclic aliphatic amine)
and para-nitrochlorobenzene produce 78% (1j), while propyl
amine and para-cyanochlorobenzene produced 71% (1k)
transformation to the desired coupling product.
2d, 89%
2e, 83%
2f, 69%
H
H
N
H
N
N
p-MePh
p-MePh
N
N
Ph
O2N
2g, 77%
2h, 76%
2i, 73%
Reaction conditions: Amines (1mmol), arylhalide (1mmol),
Cp*Co(CO)I2 (1 mol%), Cu(OAc)2 (10 mol%), 100 °C, 4 h.
The scope of the reaction was also investigated for aromatic
amines (Table 4). The reaction of aniline with chlorobenzene
was found to be quite efficient, and a 86% (3a) yield was
afforded from the reaction. Para-nitro and para-
triflouromethylchlorobenzenes produce excellent yields of
88% (3b) and 85% (3c) respectively. The reaction of para-
methylchlorobenzene
affords 73% (3d) and 80% (3e) yield respectively. 2-
Chloropyridine and aniline exhibited considerable
transformation of 76% (3f). 2-Nitro and 2-
methylchlorobenzene reacts with aniline to produces 70% (3g)
and 68% (3h) of corresponding amine products. Halide
substituted anilines and other withdrawing functionalities like
NO2 (ortho- and para-) failed to transform the desire products.
However, the donor group functionalised aniline were
identified as active substrates for the coupling reaction. Para-
methylaniline and para-methoxyaniline produces 67% (3i) and
72% (3j) yield of their respective coupling products
and
para-methoxychlorobenzene
a
Furthermore, the substrate scope was extended to benzylic
amine and excellent results were obtained in most of the
reactions (Table 3). The excellent yield of 89% (2a) was
afforded in the reaction of benzyl amine and chlorobenzene.
Electron withdrawing groups such as NO2, CF3 and C-N were
found to be well tolerated. The reactions of para-nitro, para-
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Please do not adjust margins
Green Chemistry
Page 4 of 6
COMMUNICATION
Journal Name
respectively. 2-methylaniline also produces 63% (3k) yield of exclusively produces the diphenylamine (Scheme 4). Another
View Article Online
DOI: 10.1039/D0GC02819C
desire coupling product.
Table 4. Scope reaction of anilines and aryl chlorides
reaction using a mixture of benzylamine and aniline with
chlorobenzene produces a comparative yield in the ratio of
1.4: 1. The reaction between benzyl amine and chlorobenzene
was dominant (Scheme 5).
Cp*Co(CO)I2 (1 mol%)
H
Cl
NH2
N
X
Cu(OAc)2 (10 mol%)
100 oC, 4 h
+
R1
R
R
R1
X
NH2
R
= H, Me, OMe
R1 = H, EWG, Me, OMe
X = CH, N
Cp*Co(CO)I2 (1 mol%)
Cl
Cu(OAc)2 (10 mol%)
+
+
N
Reactions of substituted arylchlorides and aniline
100 C, 4h
H
H
N
NH2
H
N
H
H
N
1.4 : 1
N
Scheme 5. Competitive reaction of 1° amines & chlorobenzene
O2N
F3C
3a, 86%
3b, 88%
3c, 85%
Another competitive trail includes a comparison between
primary and secondary aliphatic amines. In this trial, two
individual reactions of chlorobenzene, one with propylamine
and pyrrolidine (scheme 6), and another with propylamine and
diethylamine (Scheme 6 and 7) were studied. In both
reactions, coupling was dominated with secondary amine.
H
N
H
N
H
N
N
O
3d, 73%
3e, 80%
3f, 76%
NO2
H
N
H
N
NH2
Cp*Co(CO)I2 (1 mol%)
Cl
Cu(OAc)2 (10 mol%)
N
+
H
100 C, 4h
3h, 68%
N
3g, 70%
Reaction of substituted anilines and chlorobenzene
Scheme 6. Competitive reaction of 1° and 2° aliphatic amines
H
N
H
N
H
N
NH2
Cp*Co(CO)I2 (1 mol%)
Cu(OAc)2 (10 mol%)
Cl
O
N
+
100 C, 4h
3i, 67%
3k, 63%
3j, 72%
NH
Reaction conditions: Amine (1mmol), Arylhalide (1mmol),
Scheme 7. Competitive reaction of 1° and 2° aliphatic amines
Cp*Co(CO)I2 (1 mol%), Cu(OAc)2 (10 mol%), 100 °C, 4 h,
Furthermore, comparing the secondary aliphatic amines (cyclic
and acyclic amines, produces the product with only with cyclic
amine (Scheme 8). Also, the experiments comparing secondary
aromatic amine i.e. diphenylamine with pyrrolidine and
diethylamine yield products only with aliphatic amines
(Scheme 9).
To study the selectivity trend of present coupling towards
varies amines and arylhalides, some intermolecular
competitive experiments were performed. A reaction of para-
nitrochloro benzene and para-methylchlorobenzene with
pyrrolidine shows a complete selectivity towards the electron-
withdrawing functionality. These results indicate the faster
coupling of the reaction for electron-withdrawing
functionalized aryl halide.
H
N
Cp*Co(CO)I2 (1 mol%)
Cl
Cu(OAc)2 (10 mol%)
100 C, 4h
N
+
Cp*Co(CO)I2 (1 mol%)
Cu(OAc)2 (10 mol%)
Cl
Cl
N
NH
+
+
100 C, 4h
N
O2N
H
O2N
Scheme 8. Competitive reaction of 2° amines & chlorobenzene
Scheme 3. A competitive reaction of pyrrolidine with a mixture
of p-nitrochlorobenzene and p-methylchlorobenzene
NH
Cp*Co(CO)I2 (1 mol%)
NH2
Cl
N
Cu(OAc)2 (10 mol%)
100 C, 4h
Cp*Co(CO)I2 (1 mol%)
Cu(OAc)2 (10 mol%)
+
H
Cl
N
H
+
N
100 C, 4h
NH2
Scheme 9. competitive reaction of 2° amines & chlorobenzene
Scheme 4. competitive reaction of 1° amines (aromatic and
aliphatic) with chlorobenzene
Based on the literature evidences, a plausible mechanism is
drawn (Scheme 10). Probably, the catalytic cycle initiates with
the reduction of Cp*Co(III) complex (1) to Cp*Co(I)
intermediate (2). However, the source of this reduction
Several other control experiments justifying the selectivity
towards various amines are also performed. A reaction using a
mixture of propylamine and aniline with chlorobenzene
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Please do not adjust margins
Page 5 of 6
Green Chemistry
Journal Name
COMMUNICATION
Jaipur for the research fellowships. Authors also acknowledge the
process is not confirmed, but it might be probably obtained by
the reduction of cationic intermediate25 [Cp*CoOAc]+, which
can be formed by the interaction of 1 and Cu(OAc)2. However,
there is possibility that amine may be involve in this reduction
process.26 Intermediate (2) undergoes oxidative addition with
arylchloride to give adduct (3). This interact with amine and
produce an intermediate (4) and eliminate an ammonium salt,
formed by interactions of HCl and available amine.
Intermediate (4) undergoes reductive elimination and
ultimately produces the desired product and regenerates the
Cp*Co(I) complex for the next catalytic cycle.
View Article Online
MRC, MNIT Jaipur for providing characterisation facilities.
DOI: 10.1039/D0GC02819C
Notes and references
1
2
3
4
W. Liu, B. Sahoo, K. Junge, M. Beller, Acc. Chem. Res. 2018,
51, 1858−1869
W. Ai, R. Zhong, X. Liu, Q. Liu, Chem. Rev. 2019, 119, 2876-
2953
S. Bhunia, G. G. Pawar, S. V. Kumar, Y. Jiang, D. Ma, Angew.
Chem. Int. Ed. 2017, 56, 16136–16179
(a) F. Ullmann, J. Bielecki, Berichte der deutschen chemischen
Gesellschaft 1901, 34, 2174 – 3185; (b) M. S. Kharascah, E. K.
Fields, J. Am. Chem. Soc. 1941, 63, 2316-2320
R. Hili, A. K. Yudin, Nature Chemical Biology 2006, 2, 284–287
P. A. Forero-Cortés, A. M. Haydl, Org. Process Res. Dev. 2019,
238, 1478-1483
5
6
7
8
9
R. W. Dugger, J. A. Ragan, D. H. B. Ripin, Org. Process Res.
Dev. 2005, 9, 253 - 258
J. Bariwal, E. Van der Eycken, Chem. Soc. Rev. 2013, 42, 9283
- 9283
G. C. Fortman, S. P. Nolan, Chem. Soc. Rev. 2011, 40, 5151 -
5169
10 D. R. Pye, N. P. Mankad, Chem. Sci. 2017, 8, 1705 – 1718.
11 M. M. Heravi, Z. Kheilkordi, V. Zadsirjan, M. Heydari, M. J.
Malmir, Organomet. Chem. 2018, 861, 17 - 104
12 C. Sambiagio, S. P. Marsden, A. J. Blacker, P. C. McGowan,
Chem. Soc. Rev. 2014, 43, 3525-3550
13 Y. Sunesson, E. Limé, S. O. N. Lill, R. E. Meadows, P. J. Norrby,
Org. Chem. 2014, 79, 11961−11969
14 J. C. Vantourout, H. N. Miras, A. I. Llobet, S. Sproules, A. J. B.
Watson, J. Am. Chem. Soc. 2017, 139, 4769-4779
15 R. Dorel, C. P. Grugel, A. M. Haydl, Angew. Chem. Int. Ed.
2019, 58, 17118 - 17129
16 (a) Y. Sunada, H. Kawakami, T. Imaoka, Y. Motoyama, H.
Nagashima, Angew. Chem. Int. Ed. 2009, 48, 9511 –9514. (b)
P. Mathur, R. K. Joshi, B. Jha, A. K. Singh, S. M. Mobin, J.
Organomet. Chem. 2010, 695, 2687 – 2694. (c) M. Bourrez, F.
Molton, S. Chardon-Noblat, A. Deronzier, Angew. Chem. Int.
Ed. 2011, 50, 9903-9906. (d) P. Mathur, R. K. Joshi, D. K. Rai,
B. Jha, S. M. Mobin, Dalton Trans. 2012, 41, 5045 - 5054.
17 (a) P. Mathur, B. Jha, R. Raghuvanshi, R. K. Joshi, S. M.
Mobin, J. Organomet. Chem. 2012, 712, 7 – 14. (b) T.
Dombray, C. Helleu, C. Darcel, J.-B. Sortais, Adv. Synth. Catal.
2013, 355, 3358-3362. (c) P. Mathur, D. K. Rai, R. K. Joshi, B.
Jha, S. M. Mobin, Organometallics 2014, 33, 3857 – 3866. (d)
Z. Maeno, T. Mitsudome, T. Mizugaki, K. Jitsukawa, K.
Kaneda, Chem. Commun. 2014, 50, 6526
18 (a) P. Mathur, D. K. Rai, R. K. Joshi, B. Jha, S. M. Mobin,
Organometallics 2014, 33, 3857 – 3866. (b) R. K. Joshi, N.
Satrawala, Tetrahedron Lett. 2017, 58, 2931 – 2935. (c) S.
Pandey, K. V. Raj, D. R. Shinde, K. Vanka, V. Kashyap, S.
Kurungot, C. P. Vinod, S. H. Chikkali, J. Am. Chem. Soc. 2018,
140, 4430–4439
19 P. G. Chirila, C. J. Whiteoak, Dalton Trans. 2017, 46, 9721-
9739
20 A. K. Srivastava, N. Satrawala, M. Ali, Charu Sharma, R. K.
Joshi, Tetrahedron Lett. 2019, 60, 151283
21 S. Fukagawa, Y. Kato, R. Tanaka, M. Kojima, T. Yoshino, S.
Matsunaga, Angew. Chem. Int. Ed. 2019, 58, 1153 – 1157.
22 B. Khan, V. Dwivedi, B. Sundararaju, Adv. Synth. Catal. 2020,
362, 1195 - 1200
23 B. H. Lipshutz, D. M. Nihan, E. Vinogradova, B. R. Taft, Z. V.
Boskovic, Organic Lett. 2008, 10, 4279 – 4282
Scheme 10. The plausible mechanism for the catalytic reaction
Conclusions
A bimetallic catalytic system consisting of Cp*Co(CO)I2 and
Cu(OAc)2 complexes catalytically coupled the aryl chloride and
amines and established a strongly feasible strategy for the C-N
coupling reactions. The present method demands very less
amount of inexpensive Co and Cu metal catalyst and works
efficiently in base free and solvent-free conditions. The
present strategy is also found to be highly suitable for the
primary and secondary aliphatic amines, benzylic amines and
aniline. Moreover, the reaction has a bit advantages for the
electron-withdrawing functionalized aryl halides, moreover,
this is the first report of Cp*Co(III) catalysed cross-coupling of
aryl chloride and amines.
Conflicts of interest
“There are no conflicts to declare”.
24 C. Sharma, A. K. Srivastava, K. N. Sharma, R. K. Joshi, Org.
Biomol. Chem. Org. Biomol. Chem., 2020, 18, 3599-3606
25 J. Ghorai, A. C. S. Reddy, P. Anbarasan Chem. Eur. J. 2016, 22,
16042 – 16046.
26 J. D. S. Newman, G. J. Blanchard Langmuir 2006, 22, 5882-
5887.
Acknowledgements
Raj K. Joshi, thanks to CSIR (01(2996)/19/EMR-II) for financial
assistance. Avinash K. Srivastava and Charu Sharma thanks to MNIT
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins

Green Chemistry
Page 6 of 6
View Article Online
DOI: 10.1039/D0GC02819C