Nickel-catalysed alkylation of C(sp3)-H bonds with alcohols: direct access to functionalised N-heteroaromatics

Article abstract of DOI:10.1039/c8cc06370b

The first base-metal catalysed coupling of primary alcohols with methyl-N-heteroaromatics is reported. The use of an earth abundant and nonprecious NiBr₂/L1 system enables access to a series of C(sp³)-alkylated N-heteroaromatics. Mechanistic studies have established the participation of a hydrogen-borrowing strategy for α-alkylation.

Full text of DOI:10.1039/c8cc06370b

View Article Online
View Journal
ChemComm
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: D. Banerjee, M.
Vellakkaran, J. Das and S. Bera, Chem. Commun., 2018, DOI: 10.1039/C8CC06370B.
This is an Accepted Manuscript, which has been through the
Volume 52 Number
1 4 January 2016 Pages 1–216
Royal Society of Chemistry peer review process and has been
accepted for publication.
ChemComm
Accepted Manuscripts are published online shortly after
Chemical Communications
www.rsc.org/chemcomm
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
author guidelines.
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, outlined
in our author and reviewer resource centre, 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 1359-7345
COMMUNICATION
Marilyn M. Olmstead, Alan L. Balch, Josep M. Poblet, Luis Echegoyenet al.
Reactivity differences of Sc3N@C2n (2n 68 and 80). Synthesis of the
first methanofullerene derivatives of Sc N@D5h-C80
=
3
rsc.li/chemcomm

Please do not adjust margins
ChemComm
Page 1 of 4
View Article Online
DOI: 10.1039/C8CC06370B
COMMUNICATION
Nickel-Catalysed Alkylation of C(sp3)-H Bond with Alcohols: Direct
Access to Functionalised N-Heteroaromatics
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
www.rsc.org/
Mari Vellakkaran,ǂ Jagadish Das,ǂ Sourajit Bera, and Debasis Banerjee
*
The first base-metal catalysed coupling of primary alcohols coupling partner. Notable breakthrough by Kempe,9a on well-
with methyl-N-heteroaromatics is reported. Use of an earth defined Ir-catalysed alkylation of N-heteroaromatics is worth
abundant and nonprecious NiBr2/L1 system enables to access mentioning. Later, Obora and co-workers reported
a series of C(sp3)-alkylated N-heteroaromatics. Mechanistic functionalisation of 2-methyl heteroarenes using Ir-catalyst.9b
studies established the participation of hydrogen-borrowing Recently, Ru-catalysed ligand free alkylation as well as Pt-
strategy for α-alkylation.
supported heterogeneous catalysts has also been developed
for alkylation of methyl N-hetero aromatics using alcohols
Transition metal-catalysed alkylation of C(sp3)-H bond for following HB approach (Scheme 1a).9c,d
construction of carbon-chain elongated products constitutes a
(a) Pr evious W ork
fundamental challenge in organic synthesis. Due to high
C(sp3)-H bond dissociation energy, often an efficient and
selective functionalisation of alkyl chain represents a key issue
in catalysis. Therefore, since last decade significant efforts
have been directed involving C-H bond activation using alkyl
halides,1 directing group assisted functionalisation of C(sp3)-H
bond with olefins,2 reductive alkylation including nucleophilic
Ir, Ru, Pt
Het-Ar
Het-Ar
HO
R
R
(b) This work: Fir st base-metal catalysed C(sp3)-H alkylation
X
Ni
X
Phen
HO
R
N
N
R
H2
O
Aromatic primary alcohols
22 examples
substitutions as well as
α
-alkylation of ketone enolates and
Aliphatic alcohols (including unsaturated)
up to 97% yield
related studies were documented.3-4
(iso)Quinaldine, Pyrazine and Pyridine derivatives
Scheme 1: (a) Precious metal-catalysed alkylation of methyl N-heteroaromatics; (b)
Nickel-catalysed coupling of alcohols with methyl N-heteroaromatics.
N-Heteroaromatics and their derivatives are important
targets in medicines, pharmaceuticals, material chemistry and
significantly used as intermediates in natural products and
ligands in catalysis.5 Thus, functionalisation of C(sp3)-H bond in
methylazaarenes provides direct access to chain-elongated
N-heteroaromatics with valuable applications. However, such
transformations often limited with pre-functionalised alkyl
halides, carbonates or esters and often required harsh reaction
conditions involving generation of stoichiometric equivalents
of waste.6 Therefore, development of environmentally benign,
sustainable and atom-economic alkylation technology for
C(sp3)-H bond in N-heteroaromatics is still a demand goal.7
Notably, direct application of highly abundant and renewable
alcohols would be a promising alternative to the above
process.6b Nevertheless, currently, metal-catalysed borrowing
hydrogen (HB) approach has been identified as an elegant tool
to construct C-X (X = C, N etc.) bonds.8 In this direction, only
handful examples are known based on precious metal-
catalysts (Ir-, Ru-, and Pt) for such C(sp3)-H bond
functionalisation in N-heteroaromatics using alcohol as
However, recent trends in catalysis is to replace the precious
and expensive metal-catalysts with earth abundant and rare-
noble metal-catalysts for such key catalytic conversions.10a,b
Therefore, development of sustainable catalytic protocol
involving renewable resources in combination with non-
precious metal catalysts is in demand. For instance, recently
Mn-catalysed α-olefination of N-heteroaromatics are reported
using alcohols.10c,d Nevertheless, to the best of our knowledge,
till date, no nickel catalysed protocol for coupling of primary
alcohols with methyl-N-heteroaromatics is known.11 Herein,
we report the first example of an earth-abundant base metal
catalysed route for alkylation of C(sp3)-H bond in N-hetero
aromatics, such as, quinolines, pyridines and pyrazines
(Scheme 1, b).
In our continuous efforts for Ni-catalysed sustainable
transformations using renewable alcohols, recently we
developed the amination and amidation of primary alcohols
including the construction of N-heterocycles.12 Further to
explore the direct functionalisation of C(sp3)-H bond using
alcohols to chain-elongated methyl-N-heteroaromatics, we
realised the potential role of diversely available nitrogen
ligands for nickel to forge the new C-C bond. Hence, to
optimised the efficient catalytic protocol initially, five different
nickel pre-catalysts having oxidation state of Ni(0) and Ni(II)
Department of Chemistry, Laboratory of Catalysis and Organic Synthesis, Indian
Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India.
E-mail: dbane.fcy@iitr.ac.in
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Please do not adjust margins
ChemComm
Page 2 of 4
View Article Online
DOI: 10.1039/C8CC06370B
COMMUNICATION
Journal Name
were examined with the model reaction of quinaldine 1a and Quantitative product yield of 3e was achieved when sterically
benzyl alcohol 2a (Table 1, entries 1-5). Gratifyingly, we hindered
2-methyl benzyl alcohol was used. To our
4-methoxybenzyl alcohol as well as 1-
observed 70% isolated yield of α-alkylated product 3a, when, a delight,
combination of 10 mol % NiBr2, 20 mol % 1,10- naphthalenemethanol furnished the desired alkylated product
phenthroline L1 in combination with 0.25 mmol of t-BuOK at with excellent isolated yield, 84-96% respectively (Table 2, 3f
130 °C in toluene were used (entry 2).
and 3g).
Gratifyingly, more challenging long chain C8-C12 renewable
alkyl alcohols, efficiently participated in C(sp3)-H bond
functionalisation with 1a under standard conditions and
resulted chain-elongated C2-alkylated N-heteroaromatics in up
Table 1: Optimisation of the reaction conditionsa
to 60% yield 3h
-3j. To our delight, renewable terpenoid
intermediate citronellol could be employed for the
α
-
alkylation and afford 47% isolated yield of 3k. It is noteworthy
to mention that, this chemo-selective transformation of
unsaturated alcohol represents a rare instance under Ni-
catalysis.10-11 To our delight, we witnessed an excellent
reactivity profile of various alkyl and benzyl alcohols using
inexpensive nickel-catalysts.
entry catalyst (mol %)
ligand
(mol %)
L1 (20)
L1 (20)
L1 (20)
L1 (20)
L1 (20)
L1 (50)
L1 (50)
L1 (12.5)
L1 (25)
-
base
conv (%)
3a
3a’
47
25
34
48
22
0
1
2
NiCl2 (10)
NiBr2 (10)
Ni(acac)2 (10)
NiCl2(DME) (10)
Ni(cod)2 (10)
NiBr2 (10)
NiBr2 (10)
NiBr2 (2.5)
NiBr2 (5.0)
-
t-BuOK
t-BuOK
t-BuOK
t-BuOK
t-BuOK
t-BuOK 100 (96)b
t-BuOK 100 (97)b
53
73 (70)b
30
3
Table 2: Ni-catalysed
α
-alkylation of methyl N-heteroaromaticsa
4
13
5
8
X
X
NiBr2 (10 mol %)
6
7 c
Phen (50 mol %)
HO
R
t-BuOK (1.0 equiv)
toluene, 140 °C, 24 h
N
N
3a-3v
R
0
1a-1i
2a-2k
8
t-BuOK
t-BuOK
t-BuOK
-
8
13
0
36
18
0
Scope of Alcohols:
9
10
11
N
N
N
NiBr2 (10)
L1 (50)
0
0
3b, 95%b
3a, 97%b
3c, 78%
Reaction conditions: aUnless otherwise specified, quinaldine 1a (0.25 mmol),
benzyl alcohol 2a (0.50 mmol), NiBr2 (10 mol %), phen (X mol %), t-BuOK (0.25
mmol), toluene (2.0 mL), Schenk tube under nitrogen atmosphere, 130 °C oil
bath, 24 h reaction time. bIsolated yield (average of two run). c140 °C oil bath, 24
h reaction time. L1 = 1,10-phenanthroline. L2 = 2,9-dimethyl 1,10-phenanthroline. L3
= bipyridine. L4 = 4,4’- dimethylbipyridine. L5 = 2,2'-biquinoline.
N
N
N
3d, 95%
3e,
94%
3f, 96%
OMe
N
N
N
Further, application of a variety of nitrogen ligands L2-L5 did
not result any product 3a, instead we observed up to 47%
3g, 84%
3h, 60%
3i, 48%
Scope of Aliphatic Alcohols:
MeO
conversion of
α-olefinated product 3a’ using GC-MS analysis
(SI, Table S2). This results evident the significant role of ligands
to achieve higher product yields. At this point, we envisioned
that, ligands might be playing a crucial role for hydrogenation
N
N
N
3l, 62%c
3j, 38%
3k, 47%
Scope of Quinaldine derivatives:
of the inadequate amount of α-olefinated product 3a’ present
N
in the reaction mixture. Therefore, we examined the role of
additional ligands and to our delight, almost quantitative yield
of product 3a was observed with 99% selectivity (entries 6-7
and SI Table S6). Next, application of different bases, solvents
as well as control experiments resulted only moderate product
yield (SI, Table S3-S6). As expected, product yield suppress
significantly when, a lower catalyst/ligand combination was
employed (entries 8-9). Control experiments in absence of
catalyst, ligand and base shows their potential role as
individual catalytic component (Table 1, entries 10-11 and SI
Table S1-S6).
N
N
O
OMe
3m, 92%c
60%c
3n,
3o, 80%
Scope of Pyrazine and Pyridine derivatives:
N
N
N
N
N
N
3q, 71%c
3p, 92%
3r, 55%c
OMe
Et
N
Ph
Ph
N
N
N
N
Ph
3u, R = H 38%d
3v, R = Me 30%d
3s, 28%e
R
R
3t, 52%
Reaction conditions: aQuinaldine
NiBr2 (10 mol %), phen (50 mol %), t-BuOK (0.25 mmol), toluene (2.0 mL),
1
(0.25 mmol), alcohol
2
(0.50 mmol),
After having identified the optimum conditions, nickel-
catalysed functionalisation of C(sp3)-H bond of 2-methyl
quinoline was performed using a series of electronically
different benzyl alcohols (Table 2). Pleasingly, irrespective of
the electronic nature, almost quantitative yields of C2-alkylated
Schenk tube under nitrogen atmosphere, 140 oC oil bath, 24 h reaction
time. b130 oC, 24 h. ct-BuOK (0.375 mmol) was used. d
1
(0.25 mmol), alcohol
(1.0 mmol), NiBr2 (20 mol%), phen (100 mol%), t-BuOK (0.50 mmol) were
used. eGC-MS conversion.
2
Next, functionalisation of C(sp3)-H bond of various methyl
N-heteroaromatics 3b-3d were obtained (Table 2).
N-heteroaromatics using benzyl alcohols were demonstrated
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
ChemComm
Page 3 of 4
View Article Online
DOI: 10.1039/C8CC06370B
Journal Name
COMMUNICATION
under standard conditions (Table 2). For instance, 2-methyl in 39% yield along with 55% conversion to 3a’ (Scheme 3a).
quinoline substituted with methoxy or alkoxy groups at However, when using 40% L1 with NiBr2.Phen, 85% yield of 3a
different position of the aryl ring (C6 or C8 position) furnished was obtained. These experimental results provide evidences
the desired products 3l
(Table 2). Importantly, 2-methyl isoquinoline also participated 3a).
in the -alkylation process and efficiently transformed into the
-3n in up to 60-92% isolated yield for the role of excess ligand in the hydrogenation step (Scheme
α
excellent product yield (Table 2, 3o). Further, scope of the
alcohols alkylation were directed using C2-alkylated pyrazines,
moderate to excellent isolated yield of 3p-3r were obtained
(Table 2). Notably, reaction with 2-methyl pyridine was
sluggish under the optimised conditions and observed
diminished product yield of 3s. The catalytic protocol could be
applied for the synthesis of symmetric pyrazine derivatives.
Gratifyingly, when 2,5-dimethyl as well as 2,6-dimethyl
pyrazine were employed with benzyl alcohols, moderate yield
of bis-alkylated pyrazines 3t-3v were obtained (Table 2).
Notably, the catalytic protocol is tolerant to nitrogen
heterocycles (pyridine, pyrazine, quinolines etc.), allylic ethers,
including alkene and alkoxy moieties. Remarkable
transformations in the presence of reducible groups, such as,
terminal alkene evident the synthetic potential of the
established protocol.
Scheme 3: Preliminary mechanistic studies.
Scheme 2: Proposed mechanism for C2-alkylated N-heteroaromatics with alcohols
Additionally, we made an attempt to prepare the Ni-H
species of NiBr2.Phen and was not successful (SI, Scheme S7,
i).13 At that point, when, electron rich tri-cyclohexyl phosphine
was used, defined complex (Cy)3PNiBr2 and the Ni-hydride
species (Cy)3PNiBrH, were readily prepared,12 and employed in
Next, we studied the preliminary mechanistic insight for such
C(sp3)-H bond functionalisation of methyl N-heteroaromatics
using Ni-catalyst. To date, there is no such mechanistic study
is reported for α-alkylation of C2-alkylated N-heteroaromatics
with primary alcohols. During the progress of the reaction we
realised that, such Ni-catalysed α-alkylation, consisting of
multi-step process, such as, dehydrogenation of alcohol 2a to
aldehyde 2a’, where transient Ni-H species is generated
(Scheme 2). Thereafter, base mediated isomerisation of 1a to
1a’ followed by reaction with aldehyde 2a’ resulted the
stoichiometric equiv. with
α-olefinated product 3a’ under
standard conditions. Pleasingly, 3a was detected in the GC-MS
analysis of the crude reaction mixture (Scheme 3d and SI,
Scheme S7, ii). These experimental outcomes are in strong
agreement with the participation of Ni-H species for C(sp3)-H
bond functionalisation of methyl N-heteroaromatics.
Further, we performed
a series of deuterium-labeling
α
-olefinated product 3a’. At this point, hydrogenation of 3a’ by
experiments for α-alkylation process (Scheme 3, 3b-3c).
Ni-H species resulted the desired product 3a. However, we
realised that, nitrogen ligands plays a key role to achieve
selective hydrogenation of 3a’ (Scheme 2).
Initially,
α
-olefinated product 3a’ was employed with 2a and
2a-d2
(92% D) under standard conditions, and resulted 3a
and 3a-d2 were obtained in moderate yields and exhibited
56% and 61% incorporation of deuterium in -and -position
Further, to confirm the participation of 1a’
,
deuterium
d1 and
α
of 3a-d2 (Scheme 3c and SI Scheme S3). Afterward, α-
β
labeling experiments using 2a-d2 (92% D), resulted 1a
-
1
alkylation of 1a with 2a-d1 (98% D) was performed, H-NMR
detected using GC-MS analysis of the crude reaction mixture
(Schemes 2 and 3b). Next, to understand the participation of
key Ni-intermediate species, NiBr2.Phen was prepared,12 and
independently employed in catalytic (10 mol %) amount in the
model reaction. Under optimised conditions, 3a was obtained
and GC-MS analysis detected the formation of 3a-d2 along
with deuterium incorporation at variable ratio in α-and β-
position (Scheme 3b and SI Scheme S1). In addition, a
crossover experiment using 1:1 mixture of 2a and 2a-d2 under
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
ChemComm
Page 4 of 4
View Article Online
DOI: 10.1039/C8CC06370B
COMMUNICATION
Journal Name
C. MacMillan, Science, 2015, 349, 1532; (c) B. Li, C. Darcel
and P. H. Dixneuf, Chem. Commun., 2014, 50, 5970.
standard conditions of Table 2, afford the formation of H/D-
scrambled product 3a-d2 (Scheme 3b and SI Scheme S2).14
These deuterium labelling experiments strongly support the
micro-reversible transformation for the alkylation process
under nickel-catalysis and the formation of H/D-scrambled
products provide evidences for the participation of the
hydrogen borrowing strategy. 12,14 Notably, when the reaction
of 1a was performed with benzyl alcohol 2a-d1, we did not
observe any deuterated labeling product and only, 3a was
obtained in 84% yield, suggests that, hydrogen in hydroxyl
group, does not participate in the hydrogen shuffling involving
Ni-H species (Scheme 3b). Further, we studied the progress of
the alkylation reaction and monitored using gas-
chromatography over time (SI, Scheme S5). The reaction was
interrupted after five hour and the reaction profile indicating
the formation of intermediate 3a’ in faster rate, whereas,
hydrogenation to 3a are quite slow. These kinetic experiments
revealed the crucial role of excess ligand and another
equivalent of alcohol to achieve higher product yield. Finally,
to determine the rate and order of the reaction, we performed
two sets of kinetic studies (SI, Scheme S6). First order kinetics
3
For selected examples, see: (a) K. Yuan, F. Jiang, Z. Sahli, M.
Achard, T. Roisnel and C. Bruneau, Angew. Chem., Int. Ed.,
2012, 51, 8876; (b) B. Sundararaju, M. Achard, G. V. Sharma
and C. Bruneau, J. Am. Chem. Soc., 2011, 133, 10340; (c) B.
Sundararaju, Z. Tang, M. Achard, G. V. M. Sharma, L. Toupet
and C. Bruneau, Adv. Synth. Catal., 2010, 352, 3141; (d) F.
Jiang, M. Achard and C. Bruneau, Chem.-Eur. J., 2015, 21
,
14319; (e) Z. Sahli, B. Sundararaju, M. Achard and C.
Bruneau, Green Chem., 2013, 15, 775.
For selected examples, see: (a) G. Casiraghi, L. Battistini, C.
Curti, G. Rassu and F. Zanardi, Chem. Rev., 2011, 111, 3076;
(b) C. Palomo, M. Oiarbide and J. M. Garcia, Chem. Soc. Rev.,
2004, 33, 65.
4
5
(a) L. C. Campeau and K. Fagnou, Chem. Soc. Rev., 2007, 36
,
1058; (b) E. Vitaku, D. T. Smith and J. T. Njardarson, J. Med.
Chem., 2014, 57, 10257.
(a) B. M. Trost, Science, 1991, 254, 147; (b) K. Barta and P. C.
Ford, Acc. Chem. Res., 2014, 47, 1503.
(a) E. Pasquinet, P. Rocca, F. Marsais, A. Godard and G.
Quéguiner, Tetrahedron, 1998, 54, 8771; (b) B. M. Trost and
D. A. Thaisrivongs, J. Am. Chem. Soc., 2008, 130, 14092; (c) B.
6
7
M. Trost and D. A. Thaisrivongs, J. Am. Chem. Soc., 2009, 131
,
12056; (d) B. M. Trost, D. A. Thaisrivongs and J. Hartwig, J.
Am. Chem. Soc., 2011, 133, 12439.
with respect to quinaldine 1a was observed for α-alkylation of
N-heteroaromatics considering a steady state approximation
8
9
(a) G. E. Dobereiner and R. H. Crabtree, Chem. Rev., 2010,
110, 681; (b) G. Guillena, D. J. Ramon and M. Yus, Chem.
Rev., 2010, 110, 1611; (c) A. J. A. Watson and J. M. J.
Williams, Science, 2010, 329, 635; (d) S. Bähn, I. Sebastian, L.
Neubert, M. Zhang, H. Neumann and M. Beller,
for benzyl alcohol.
In conclusion, we reported the first Ni-catalysed
functionalisation of C(sp3)-H bond of methyl N-
heteroaromatics using primary alcohols. Easily available,
inexpensive Ni-catalyst and 1,10-phenthroline ligand enables
ChemCatChem., 2011, 3, 1853; (e) J. Moran, M. J. Krische,
Pure Appl. Chem., 2012, 84, 1729.
(a) B. Blank and R. Kempe, J. Am. Chem. Soc., 2010, 132, 924;
(b) Y. Obora, S. Ogawa and N. Yamamoto, J. Org. Chem.,
2012, 77, 9429; (c) C. Chaudhari, S. M. A. H. Siddiki and K.
Shimizu, Tetrahedron Letters, 2013, 54, 6490; (d) T. Feng, H.
Li, D. Young and J. Lang, J. Org. Chem., 2017, 82, 4113. For
recent selected examples, see: (a) Z. Tan, H. Jiang and M.
Zhang, Chem. Commun., 2016, 52, 9359; (b) C.-S. Wang, T.
the long chain
C2-alkylated N-heteroaromatics in
up to quantitative yields. The catalytic system allow the
transformations in the presence of reducible functional
moieties, such as, allylic ether and alkenes including
unsaturated alcohols. Initial mechanistic studies strongly
support the participation Ni-H species and bifunctional nature
of the Ni-catalyst. A series of deuterium labeling experiments
revealed the involvement of the H/D exchange during the
progress of the reaction.
Roisnel, P. H. Dixneuf, and J.-F. Soulé, Org. Lett., 2017, 19
,
6720; (c) M. Xiao, D. Ren, L. Xu, S.-S. Li, L. Yu, and J. Xiao,
Org. Lett., 2017, 19, 5724; (d) Y. Fukumoto, M. Hirano, N.
Matsubara, and N. Chatani, J. Org. Chem., 2017, 82, 13649.
10 (a) R. M. Bullock, Catalysis Without Precious Metals, Eds.:
Wiley-VCH, Weinheim, 2010; (b) B. Su, Z.-C. Cao and Z.-J. Shi,
Acc. Chem. Res., 2015, 48, 886; (c) G. Zhang, T. Irrgang, T.
Dietel, F. Kallmeier, and R. Kempe, Angew. Chem. Int. Ed.
2018, 57, 9131; (d) M. K. Barman, S. Waiba, B. Maji, Angew.
Chem. Int. Ed. 2018, 57, 9126.
11 For selected reviews, see: (a) S. Z. Tasker, E. A. Standley, T. F.
Jamison, Nature, 2014, 509, 299; (b) A. Valentine and P.
Ananikov, ACS Catal., 2015, 5, 1964; (c) J. E. Dander and N. K.
Conflicts of interest
There are no conflicts to declare.
The authors thank DAE-BRNS, India (Young Scientist Research
Award to D. B., 37(2)/20/33/2016-BRNS) and IIT Roorkee (SMILE-
32). M. V. Thank SERB-NPDF (SERB-PDF/2017/002784), India for a
fellowship. J. D. and S. B. thank IIT-R and INSPIRE (DST) for
financial support.
Garg, ACS Catal., 2017, , 1413 and references cited therein;
7
(d) F. Alonso, P. Riente and M. Yus, Acc. Chem. Res., 2011,
44, 379.
12 (a) M. Vellakkaran, K. Singh and D. Banerjee, ACS Catal.,
Notes and references
2017, 7, 8152; (b) J. Das and D. Banerjee, J. Org. Chem.,
2018, 83, 3378; (c) K. Singh, M. Vellakkaran and D. Banerjee,
Green Chem., 2018, 20, 2250.
1
For selected examples, see: (a) D. Shabashov and O.
Daugulis, J. Am. Chem. Soc., 2010, 132, 3965; (b) S. Y. Zhang,
G. He, W. A. Nack, Y. S. Zhao, Q. Li and G. Chen, J. Am. Chem.
Soc., 2013, 135, 2124; (c) J. Pedroni, M. Boghi, T. Saget and
N. Cramer, Angew. Chem., Int. Ed., 2014, 53, 9064; (d) Z. Y.
Zhu, J. He, X. C. Wang and J. Q. Yu, J. Am. Chem. Soc., 2014,
136, 13194.
13 S. Chakraborty, P. E. Piszel, W. W. Brennessel and W. D.
Jones, Organometallics, 2015, 34, 5203.
14 M. H. S. A. Hamid, C. L. Allen, G.W. Lamb, A. C. Maxwell, H. C.
Maytum, A. J. A. Watsom and J. M. J. Williams, J. Am. Chem.
Soc., 2009, 131, 1766.
2
For selected examples, see: (a) F. Y. Mo and G. B. Dong,
Science, 2014, 345, 68; (b) J. L. Jeffrey, J. A. Terrett and D. W.
4 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins