Ruthenium(II)-NNN-Pincer-Complex-Catalyzed Reactions Between Various Alcohols and Amines for Sustainable C?N and C?C Bond Formation

Article abstract of DOI:10.1002/adsc.201701117

An air and moisture stable 2-hydroxypyridine based bifunctional ruthenium NNN-pincer complex catalyzed efficient (TON=42840) N-alkylation of amines under mild conditions. Surprisingly, with cyclic secondary amines this methodology selectively produced only amides. Notably, N-methylation of several amines was achieved by using methanol as a green methylating agent. Furthermore, with lower catalyst loading (0.2 mol%) and shorter reaction time (6 h) numerous substituted quinolines were synthesized from 2-aminobenzyl alcohols and secondary alcohols. The effectiveness of this protocol was further extended by successfully synthesizing 2-alkylaminoquinolines in a one-pot fashion from amino alcohol, aliphatic nitriles, and alcohols. Gram scale synthesis of various compounds was also investigated to demonstrate the synthetic applicability of this methodology. (Figure presented.).

Full text of DOI:10.1002/adsc.201701117

Title: Ruthenium(II)-NNN-Pincer-Complex-Catalyzed Reactions
Between Various Alcohols and Amines for Sustainable C-N and
C-C Bond Formation
Authors: Milan Maji, Kaushik Chakrabarti, Bhaskar Paul, Bivas
Chandra Roy, and Sabuj Kundu
This manuscript has been accepted after peer review and appears as an
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To be cited as: Adv. Synth. Catal. 10.1002/adsc.201701117
Link to VoR: http://dx.doi.org/10.1002/adsc.201701117

10.1002/adsc.201701117
FULL PAPER
Advanced Synthesis & Catalysis
DOI: 10.1002/adsc.201
Ruthenium(II)-NNN-Pincer-Complex-Catalyzed
Reactions
Between Various Alcohols and Amines for Sustainable C-N and
C-C Bond Formation
Milan Maji,a Kaushik Chakrabarti,a Bhaskar Paul,a Bivas Chandra Roy,a and Sabuj
Kundua,*
a
Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur -208016, India
Email: sabuj@iitk.ac.in
Received:
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201######.
Abstract. An air and moisture stable 2-hydroxypyridine 2-alkylaminoquinolines in a one-pot fashion from amino
based bifunctional ruthenium NNN-pincer complex catalyzed alcohol, aliphatic nitriles, and alcohols. Gram scale synthesis
efficient (TON = 42840) N-alkylation of amines under mild of various compounds was also investigated to demonstrate
conditions. Surprisingly, with cyclic secondary amines this the synthetic applicability of this methodology.
methodology selectively produced only amides. Notably, N-
methylation of several amines was achieved by using
methanol as a green methylating agent. Furthermore, with
lower catalyst loading (0.2 mol%) and shorter reaction time
(6 h) numerous substituted quinolines were synthesized from
2-aminobenzyl alcohols and secondary alcohols. The
effectiveness of this protocol was further extended by
successfully synthesizing
Keywords: Acceptorless dehydrogenative annulation, N-
methylation, quinoline, 2-alkylaminoquinoline, bifunctional
catalyst.
based catalysts are most common.[9c, 10] Recently, few
Fe[11] and Co[5b, 12] based complexes were also reported
for the amine alkylation reaction. However, air and
moisture sensitive phosphine based ligands were
Introduction
The development of atom economical, eco-friendly
and efficient methods for the synthesis of N-alkylated
amines remains a challenge in organic synthesis and is
an active area of research, particularly from the green
chemistry point of view.[1] N-Alkylated amines are
important in the fine-chemical industry and are also
key component for the synthesis of peptides, polymers,
dyes, pharmaceuticals, and pesticides.[2] Among the
numerous processes for the C-N bond forming
reactions the “borrowing hydrogen” methodology has
attracted much attention in recent years.[3] In this
methodology, inexpensive and less toxic alcohols are
transformed as alkylating partners and water is the
only by-product.[1b,4] The catalytic cycle involves
dehydrogenation of alcohols, followed by formation of
imines with the release of water molecule and finally
in-situ hydrogenation of the imines produced the
desired N-alkylated amines.[5]
crucial for many of these homogeneous systems.[9b, 9f,
11d, 12]
Scheme 1. Application of Borrowing Hydrogen and
Acceptorless Dehydrogenative Coupling protocols.
The amination of alcohol is challenging particularly
with less nucleophilic amines such as aniline.[6] Grigg
and Watanabe groups were first conveyed alkylation
of amines following the borrowing hydrogen
concept.[7] After that, several homogeneous and
heterogeneous systems were developed for the similar
transformations, among them Ir[4f, 8] and Ru[4e, 9] metal
Similar to the borrowing hydrogen protocol,
acceptorless dehydrogenative coupling reaction is also
highly significant for the sustainable and
environmentally benign synthesis of numerous
valuable complex molecules as in this case only H2 and
H2O were generated as by-products.[1c, 8c, 13] Based on
1
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10.1002/adsc.201701117
Advanced Synthesis & Catalysis
this concept Beller, Milstein, Kempe, and other groups
Various Ru(II) precursors like [RuCl2(p-cymene)]2,
RuHCl(CO)(PPh3)3, RuCl2(PPh3)3 were also tested,
which presented lower activity compared to the
complex 1a (Table 1, entries 3-5). Under similar
reaction conditions, complexes 1b, 1c and 1d with
ortho-OMe, -Me and -H groups respectively in the
pyridine ring displayed poorer catalytic activity (Table
1, entries 6-8). There was no product formation in
absence of the Ru(II) complex (Table 1, entry 10).
reported formation of several heterocyclic
14]
compounds.[13a,
Among them, the syntheses of
biologically active quinoline derivatives are greatly
attractive as they are present in various
pharmacologically important drugs and natural
products.[15] Lately, for the synthesis of quinolines
much effort is focused towards the transition metals[16]
or base[17] catalyzed cyclization of o-aminobenzyl
alcohols with ketones. Compare to this, oxidative
cyclization of o-aminobenzyl alcohols with alcohols is
relatively less explored.[8c, 18] Additionally, most of
these protocols require either large excess of ketones
or alcohols as coupling partner or sacrificial hydrogen
acceptors.[16b, 17c, 19] Hence, the development of new
efficient catalytic system for the synthesis of
quinolines from equimolar amount of amino alcohols
and alcohols under milder conditions is highly
desirable.
Recently, we observed that (2-hydroxy-2-pyridyl)-
1,10-phenanthroline containing Ru(II) complexes
displayed excellent catalytic activity in transfer
hydrogenation, β-alkylation of secondary alcohols and
α-methylation of ketones.[20] In this report, the
potential of this complex was investigated in various
other sustainable borrowing hydrogen and
acceptorless dehydrogenative coupling reactions.
Herein, we report an air and moisture stable
bifunctional ruthenium complex catalyzed efficient
synthesis of N-alkylated amines and quinolines as well
as one-pot synthesis of 2-alkylaminoquinolines under
mild conditions (Scheme 1).
Table 1. Alkylation of aniline with benzyl alcohol catalysed
by different Ru(II) complexes.[a]
Entry
Ru(II) Complex
Base
Conversion
(%)[b]
1
2
3
KOtBu
KOtBu
KOtBu
98 (97)
89 (75)
18 (4)
1a
1a′
[RuCl2(p-
cymene)]2
RuHCl(CO)(PPh3)3
4
5
6
7
8
KOtBu
KOtBu
KOtBu
KOtBu
KOtBu
KOtBu
KOtBu
NaOH
K2CO3
NaOiPr
NaOMe
KOtBu
57 (77)
32 (55)
44 (52)
79 (98)
32 (47)
56 (58)
0
32 (56)
-
21 (38)
-
RuCl2(PPh3)3
1b
1c
1d
1a
-
1a
1a
1a
1a
1a
9[c]
10
11
12
13
14
15[d]
97 (95)
Results and Discussion
[a] Reaction conditions: aniline (0.55 mmol), benzyl alcohol
(0.715 mmol), KOtBu (0.55 mmol), dioxane (2 mL) at
Initially, in order to find the optimum conditions for
the N-alkylation reaction, coupling between aniline
and benzyl alcohol was selected as a model reaction
and a series of Ru(II) NNN-pincer complexes (0.2
mol%) were screened for 12 h (Figure 1). Both
complexes 1a and 1a′ showed excellent conversion of
aniline, however selectivity for the N-benzylaniline
(2a) over N-benzylideneaniline (2a′) was greater with
complex 1a (Table 1, entries 1 and 2).
°
110 C for 12 h. [b] Conversion of aniline was determined
by GC analysis using n-dodecane as an internal standard;
(%) selectivity (2a:2a′) is given in the parenthesis. [c] 0.1
mol% Ru complex. [d] Heated for 16 h with KOtBu (25
mol%).
With the optimized conditions in hand, the generality
of the reaction was tested using different aniline
derivatives and primary alcohols as presented in Table
2. A number of aniline derivatives with both the
electron donating and withdrawing substituents at the
ortho, meta and para positions were selectively
converted to the corresponding N-alkylated anilines
with excellent yields (Table 2, entries 2a-g). The
presence of bulky substituent in the ortho position was
well tolerated (Table 2, entry 2g). The scope of various
aromatic alcohols were inspected by reacting different
substituted benzylic alcohols with aniline and they also
acted as an effective alkylating agents (Table 2, entries
2h-k). Additionally, 1-naphthylmethanol, cyclic and
acyclic aliphatic alcohols, heteroatom containing
alcohols such as furfuryl alcohol and 2-
thiophenemethanol were smoothly converted to the
desired products with slightly higher catalyst loading
(0.5 mol%) within 24 h (Table 2, entries 2l-q). To our
Figure 1. NNN-Ru(II) complexes screened in this work.
2
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10.1002/adsc.201701117
Advanced Synthesis & Catalysis
delight, this system displayed superior catalytic
activity compared to the other reported Ru(II) catalysts
and exhibited TON of 42840 for the coupling of
aniline and benzyl alcohol after 60 h using 0.001 mol%
catalyst loading. Although, Li et al. reported N-
alkylation of aromatic amines using 0.1 mol% Ru(II)
catalyst (TON up to 9500), however excess of alcohols
(2 equiv.) and prolonged reaction time (48 h) was
essential for their system.[9d]
[a] Reaction conditions: aniline (0.5 mmol), Cat. 1a (1.0
mol%), NaOMe (0.5 mmol), MeOH (1 mL) at 110 °C for 24
h, isolated yields.
Notably, complex 1a selectively provided several
mono-N-methylated amines in excellent yields using
methanol as an eco-friendly methylating reagent
following the borrowing hydrogen strategy (Table 3).
This catalytic system also tolerated challenging
substrates such as 3-aminopyridine and hexyl amine
(Table 3, entries 3e and 3f).
Table 2. Substrate scopes for the N-alkylation of amines.[a]
Surprisingly, reaction between piperidine and benzyl
alcohol under the optimized N-alkylation reaction
conditions yielded only N-benzoylpiperidine (11%)
and no N-alkylated amine product was detected. To the
best of our knowledge, there is no report of N-
alkylation as well as amidation of amines using same
catalytic condition. A mixed NHC/phosphine Ru(II)
complex mediated both these reactions were observed
by Huynh group.[24] However, the reaction conditions
for the N-alkylation and amidation were entirely
different.
Table 4. Synthesis of amides from alcohols and cyclic
amines.[a]
[a] Reaction conditions: aniline (0.55 mmol), alcohol (0.715
mmol), Cat. 1a (0.2 mol%), KOtBu (25 mol%), dioxane (2
°
mL) at 110 C for 16 h, isolated yields. [b] Cat. 1a (0.5
mol%), 24 h.
[a] Reaction conditions: amine (0.5 mmol), alcohol (0.5
N-methylated amines are vital class of compounds in
medicinal chemistry and fine chemical industries.[21]
Hence, to synthesize these molecules using methanol
as a green methylating agent has significant
importance compared to the conventional methods
which require toxic methyl halides or other strong
reagents.[22] The use of methanol in selective
monoalkylation reactions are relatively rare in the
literature due to the higher dehydrogenation energy
compare to the long chain alcohols.[1b, 4a, 8e, 23]
mmol), cat. 1a (1.0 mol%), KOtBu (0.5 mmol), dioxane (2
°
mL) at 110 C for 24 h, isolated yields. [b] Cat. 1a (2.0
mol%), 24 h.
Synthesis of amides is of great importance owing to
their high abundance in proteins, natural products,
pharmaceuticals and therapeutic drugs.[25] Piperidinyl
and morpholinyl based amides were found as potent
drugs for orexin receptor antagonist, antibiotics, and
they also showed cytotoxic activity towards certain
Table 3. N-methylation of amines using methanol.[a]
cancer
cells
and
insecticides.[26]
Direct
dehydrogenative synthesis of tertiary amides from
secondary amines and primary alcohols is an atom
economical method over the traditional amide
synthesis protocol.[27] Hence, we explored this reaction
further. Following this protocol, different tertiary
amides were obtained from piperidine and morpholine
in good to excellent yields by reacting with various
substituted benzyl alcohols, 1-naphthylmethanol and
1-butanol (Table 4). However, with N-methyl aniline
no amide product was observed (Table 4, entry 4h).
3
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10.1002/adsc.201701117
Advanced Synthesis & Catalysis
After observing the superior activity of the complex
reaction. To our delight, complex 1a efficiently
delivered the N-benzyl-3-phenylquinolin-2-amine by
coupling of 2-aminobenzyl alcohol with benzyl
cyanide followed by N-alkylation with benzyl alcohol.
Compare to the Zhang group’s work, present catalytic
system provided the desired product smoothly at lower
1a in alcohol amine coupling reaction, we explored the
sustainable synthesis of substituted quinolines by
acceptorless dehydrogenative coupling reaction of
alcohols and amino alcohols. Similar to the prior
reaction, several experiments were carried out to
establish the most suitable reaction conditions for the
dehydrogenative cross coupling reaction. Reaction of
2-aminobenzyl alcohol with 1-phenylethanol in
presence of complex 1a (0.2 mol%) and KOtBu at
120 °C in dioxane for 6 h delivered the best result (see
the supporting information). Gratifyingly, among the
Ru(II) catalyst reported till date, complex 1a exhibited
the superior reactivity in this reaction with TON up to
2000 (0.01 mol% the catalyst loading, 60 h).[18a, 19b, 28]
°
°
temperature (125 C instead of 140 C) in absence of
any expensive phosphine ligand like BINAP.
Table 6. One-pot synthesis of 2-alkylaminoquinolines.[a]
Table 5. Substrate scopes for the synthesis of quinolines.[a]
[a] Reaction conditions: amino alcohol (0.5 mmol), nitrile
(0.5 mmol), Cat. 1a (3.5 mol%), and KOtBu (0.5 mmol) at
125 °C for 0.5 h followed by addition of alcohol (1.0 mmol)
and heated for another 24 h, isolated yields.
Next, this protocol was extended to different
substrates to show the competence of the reaction. The
one-pot three component coupling of 2-aminobenzyl
[a] Reaction Conditions: 2-aminobenzyl alcohol (0.40
mmol), alcohol (0.48 mmol), cat. 1a (0.2 mol%), KOtBu
alcohol with
a
number of substituted 2-
°
(0.20 mmol), dioxane (2 mL) at 120 C for 6 h, isolated
arylacetonitriles and alcohols were tested which
provided the desired products in moderate to excellent
yields (Table 6, entries 6a-c). Acyclic aliphatic alcohol
was also used as a coupling partner although, the yield
of the product was relatively lower. Following the
optimized conditions reactions using chloro-
substituted 2-aminobenzyl alcohol also progressed
smoothly to give the desired products in moderate to
good yields (Table 6, entries 6e-f).
yields. [b] Reaction for 24 h.
Next, coupling of 2-aminobenzyl alcohol with
various substituted 1-phenylethanol, α-methyl-2-
naphthalenemethanol were carried out which
produced the desired products in good to excellent
yields (Table 5, entries 5a-g). Additionally, under the
optimized conditions aliphatic alcohols such as
1,2,3,4-tetrahydro-1-naphthol, cyclohexanol and 1-
cyclopropylethanol showed excellent results.
However, 1-phenylpropan-1-ol and 2-heptanol
presented lower yields (Table 5, entry 5h and 5k). To
expand the scope of amino alcohols, reaction of 2-
amino-5-chlorobenzyl alcohol with three different
type of alcohols were studied which also proceeded
smoothly (Table 5, entries 5m-o).
Figure 2. Gram scale synthesis.[a]
2-Alkylaminoquinolines are important structural
motifs present in several biologically active
compounds and therapeutic drugs.[29] Owing to their
high importance and motivated by Zhang groups
finding,[30] we were interested to examine potential of
complex 1a further in one-pot synthesis of 2-
alkylaminoquinolines
via
acceptorless
dehydrogenative annulation followed by N-alkylation
4
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10.1002/adsc.201701117
Advanced Synthesis & Catalysis
Agilent 7890 A Gas Chromatograph equipped with Agilent
5890 triple-quadrupole mass system.
[a] Compounds were synthesized following the respective
optimized conditions mentioned in Tables 2-5, isolated
yields. [b] Cat 1a (0.001 mol%, 60 h). [c] Cat 1a (0.01
mol%, 60 h).
General procedure for catalytic N-alkylation of amines
The stock solution of catalyst was prepared by dissolving
complex 1a in dry CH3CN. Then an aliquot of catalyst
solution (0.2 mol%) was taken into a Schlenk tube and
solvent was removed under reduced pressure. After that
amine (0.55 mmol), primary alcohol (0.715 mmol), KOtBu
(25 mol%) and 2.0 mL dioxane were added under argon
atmosphere. Then, the tube was sealed and dipped in a
The synthetic applicability of this methodology was
further established by gram scale synthesis of various
compounds which showed moderate to good yields of
the desired products (Figure 2). These results
indicates the high efficacy and potential of the present
catalytic system towards the practical application.
°
preheated oil bath at 110 C and heated for 16 h. After the
reaction, it was allowed to cool at room temperature and the
reaction mixture was passed through a small pad of neutral
alumina and directly subjected for GC analysis for
calculating conversion and product selectivity of the
reaction. The reaction mixture was concentrated under
reduced pressure and final products were isolated and
purified by column chromatography using silica gel and
hexane-ethyl acetate as eluent.
Conclusion
In conclusion, 2-hydroxypyridine based bifunctional
ruthenium NNN-pincer complex demonstrated
excellent catalytic activity in N-alkylation of various
amines under mild conditions following the borrowing
hydrogen strategy. A remarkably high TON of 42840
was achieved using 0.001 mol% complex 1a.
Surprisingly, with cyclic secondary amines this
protocol selectively produced only amides. To the best
of our knowledge, there is no report of N-alkylation as
well as amidation of amines using same catalytic
condition. Notably, selective mono-N-methylation
was achieved using methanol as an alkylating partner
which presented a greener route towards the synthesis
of N-methylated amines. Additionally, under mild
conditions with lower catalyst loading and shorter
reaction time several quinolines were synthesized
from 2-aminobenzyl alcohols and secondary alcohols.
High atom efficiency, wide substrate scope and broad
functional group tolerance makes this synthetic
process more practically applicable. The effectiveness
of this protocol was further extended by successfully
producing 2-alkylaminoquinolines in one-pot fashion.
The practical synthetic aspects were also demonstrated
by gram scale synthesis of various compounds.
Finally, bifunctional catalyst (1a) was found to be
highly efficient in both hydrogen borrowing as well as
acceptorless dehydrogenative coupling reactions.
General procedure for catalytic N-methylation of
amines
Catalyst 1a (1.0 mol%), amine (0.5 mmol) and NaOMe (0.5
mmol) were taken in an oven dried screw cap tube and 1.0
mL methanol was added. Then the tube was sealed under
argon atmosphere and dipped in a preheated oil bath at
110 °C and heated for 24 h. After completion of the reaction,
it was allowed to cool at room temperature, filtered through
a small plug of neutral alumina and directly subjected for
GC analysis for calculating conversion and product
selectivity of the reaction. Finally, the reaction mixture was
concentrated under reduced pressure the desired N-
methylated amine products were purified by column
chromatography using silica gel and hexane-ethyl acetate as
eluent.
General procedure for synthesis of cyclic amides from
alcohols and cyclic amines
Catalyst 1a (1.0 mol%) was taken into a Schlenk tube from
a freshly prepared stock solution in dry acetonitrile and
solvent was removed under reduced pressure. After that
amine (0.5 mmol), 1-phenylethanol (0.5 mmol), KOtBu (0.5
mmol) and 2.0 mL dioxane were added under argon
atmosphere. Then, the tube was sealed and dipped in a
°
preheated oil bath at 110 C and heated for 24 h. After the
reaction, it was allowed to cool at room temperature and the
reaction mixture was passed through a small pad of neutral
alumina and directly subjected for GC analysis for
calculating conversion and product selectivity of the
reaction. The reaction mixture was concentrated under
reduced pressure and final products were isolated and
purified by column chromatography using silica gel and
hexane-ethyl acetate as eluent.
Experimental Section
General procedure and materials
General procedure for quinolines synthesis
All the manipulations were carried out under argon
atmosphere either inside the argon filled glove box or by
using standard Schlenk line technique. Glasswares were
oven dried prior to use. Solvents were dried according to
literature methods. All solvents were distilled under argon
atmosphere and deoxygenated prior to use. All the
commertial reagents and metal precursors were purchased
from Sigma-Aldrich, Alfa-Aesar, Spectrochem, Avra,
SDFCL and Arora Matthey India. The metal complexes
were synthesized according to our previous work.[20, 31] 1H,
13C and 31P NMR spectra were recorded in JEOL
Spectrometer. ESI-MS were recorded on a Waters
Micromass Quattro Micro triple-quadrupole mass
spectrometer. All the GC analysis were performed using
Perkein Elmer Clarus 600 and Agilent 7890 B Gas
Chromatograph, where as GC-MS were measured using
From a freshly prepared stock solution of catalyst 1a in dry
CH3CN, an aliquot of catalyst solution (0.2 mol%) was
taken into a Schlenk tube and solvent was removed under
reduced pressure. After that 2-aminobenzyl alcohol (0.4
mmol), 1-phenylethanol (0.48 mmol), KOtBu (0.20 mmol)
and 2.0 mL dioxane were added under argon atmosphere.
Then, the tube was sealed and dipped in a preheated oil bath
°
at 120 C and heated for 6 h. After the reaction, it was
allowed to cool at room temperature and the reaction
mixture was passed through a small pad of neutral alumina
and directly subjected for GC analysis for calculating
conversion and product selectivity of the reaction. The
reaction mixture was concentrated under reduced pressure
and final products were isolated and purified by column
chromatography using silica gel and hexane-ethyl acetate as
eluent.
5
This article is protected by copyright. All rights reserved.

10.1002/adsc.201701117
Advanced Synthesis & Catalysis
General
procedure
for
synthesis
of
2-
Blacker, M. M. Farah, S. P. Marsden, J. M. J. Williams,
Angew. Chem., Int. Ed. 2009, 48, 7375-7378; i) G.
Guillena, D. J. Ramón, M. Yus, Angew. Chem., Int. Ed.
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B. M. Paine, D. J. Shermer, M. K. Whittlesey, J. M. J.
Williams, D. D. Edney, Chem. Commun. 2004, 90-91.
alkylaminoquinolines
Catalyst 1a (3.5 mol%) was taken into an oven dried
Schlenk tube and then 2-aminobenzyl alcohol (0.5 mmol),
nitrile (0.5 mmol), KOtBu (0.5 mmol) and 2.0 mL dioxane
were added under argon atmosphere. Then, the tube was
°
sealed and dipped in a preheated oil bath at 125 C and
heated for 0.5 h. Then, after cooling the reaction mixture to
room temperature under argon atmosphere, alcohol (1.0
mmol) was added and the reaction mixture was heated for
another 24 h. After the reaction, it was allowed to cool at
room temperature and the reaction mixture was passed
through a small pad of neutral alumina and directly
subjected for GC analysis for calculating conversion and
product selectivity of the reaction. The reaction mixture was
concentrated under reduced pressure and final products
were isolated and purified by column chromatography using
silica gel and hexane-ethyl acetate as eluent.
[5] a) Y. Zhang, C.-S. Lim, D. S. B. Sim, H.-J. Pan, Y. Zhao,
Angew. Chem., Int. Ed. 2014, 53, 1399-1403; b) G.
Zhang, Z. Yin, S. Zheng, Org. Lett. 2016, 18, 300-303.
[6] T. T. Nguyen, K. L. Hull, ACS Catal. 2016, 6, 8214-
8218.
[7] a) R. Grigg, T. R. B. Mitchell, S. Sutthivaiyakit, N.
Tongpenyai, J. Chem. Soc., Chem. Commun. 1981, 0
611-612; b) Y. Watanabe, Y. Tsuji, Y. Ohsugi,
Tetrahedron Lett. 1981, 22, 2667-2670.
[8] a) O. Saidi, A. J. Blacker, M. M. Farah, S. P. Marsden,
J. M. J. Williams, Chem. Commun. 2010, 46, 1541-1543;
b) A. Prades, R. Corberán, M. Poyatos, E. Peris, Chem.
Eur. J. 2008, 14, 11474-11479; c) S. Ruch, T. Irrgang,
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C. Wang, J. Smith, D. Xue, J. Xiao, Chem. Eur. J. 2015,
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Acknowledgements
We are grateful to the Science and Engineering Research Board
(SERB), India, Council of Scientific and Industrial Research
(CSIR), India, and Indian Institute of Technology Kanpur for
financial support. M.M. and B.C.R. thank the CSIR and K.C. and
B.P. thank the UGC, India, for fellowships.
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FULL PAPER
Ruthenium(II)-NNN-Pincer-Complex-Catalyzed
Reactions Between Various Alcohols and Amines
for Sustainable C-N and C-C Bond Formation
Adv. Synth. Catal. Year, Volume, Page – Page
Milan Maji,a Kaushik Chakrabarti,a Bhaskar Paul,a
Bivas Chandra Roy,a and Sabuj Kundua,*
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