Ruthenium-Catalyzed Carbonylative Coupling of Anilines with Organoboranes by the Cleavage of Neutral Aryl C-N Bond

Article abstract of DOI:10.1021/acs.orglett.0c00736

Herein, we report the first ruthenium-catalyzed Suzuki-type carbonylative reaction of electronically neutral anilines via C(aryl)-N bond cleavage. Without any ligand and base, diaryl ketones can be obtained in moderate to high yields by using Ru₃

Full text of DOI:10.1021/acs.orglett.0c00736

pubs.acs.org/OrgLett
Letter
Ruthenium-Catalyzed Carbonylative Coupling of Anilines with
Organoboranes by the Cleavage of Neutral Aryl C−N Bond
Jian-Xing Xu, Fengqian Zhao, Yang Yuan, and Xiao-Feng Wu*
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ABSTRACT: Herein, we report the first ruthenium-catalyzed
Suzuki-type carbonylative reaction of electronically neutral anilines
via C(aryl)−N bond cleavage. Without any ligand and base, diaryl
ketones can be obtained in moderate to high yields by using
Ru3(CO)12 as the catalyst and chelation assisted by pyridine. The
pyridine ring has a significant effect on both high efficiency and high
regioselectivity in the cleavage of the aryl C−N bond in anilines.
In line with the purpose of Green Chemistry, organic
ransition-metal-catalyzed carbonylative reactions are one
Tof the most powerful methodologies for the synthesis of chemistries are committing to minimize the preactivation of
various carbonyl-containing compounds in organic chemistry.1
substrates, alleviate waste production, and shorten the number
of synthetic steps in organic synthesis. Therefore, the catalytic
functionalization of unreactive bonds, such as C−H, C−C, C−
F, C−O, and C−N bonds, which widely exist in natural
products and biomolecules, has become an interesting research
subject in modern organic synthesis.6 And many successful
examples have been reported.6,7 By contrast, their carbon-
ylative transformations still remain a great challenge. Only a
few examples have been reported, except C−H bond activation
carbonylation.8 This is due to the increased difficulty in
oxidative addition in the presence of π-acidic CO, which
decreases the electron density on the metal center.
Anilines, on the other hand, are valuable commodity
chemicals and synthetic building blocks for many organic
molecules and biomolecules.9 The transformation of the aryl
C−N bond is highly desirable. But the aryl C−N bond has
high dissociation energy and is usually chemically inert due to
the p−π conjugation. Typical activation of the aryl C−N bond
includes converting the aryl C−N bond into the corresponding
highly reactive ammonium salts,10 diazonium salts,11 or
pyridinium salts.12 And the direct cleavage of the C−N bond
in electronically neutral molecules by the oxidative addition
pathway has been rarely reported.13 Particularly, there is no
result reported on carbonylative reaction via the cleavage of
aryl C−N bonds in electronically neutral anilines.
It is also very important in the chemical industry, such as the
production of acetic acid (Monsanto process) and the
Fischer−Tropsch synthesis of hydrocarbons from syngas.2
Known as an inexpensive and readily available C1 building
block, carbon monoxide (CO) can be easily produced from
fossil fuels and renewables (the gasification of waste biomass or
the electroreduction of CO2).3 Since the pioneering work of
Heck and co-workers in the 1970s,4 various transition-metal-
catalyzed carbonylative cross-coupling reactions have been
published.1,5 However, most of these reactions employ organic
(pseudo)halides such as aryl halides, aryl triflates as electro-
philic coupling partners (Scheme 1). Besides the preactivation
steps, the formation of a stoichiometric amount of halogen
waste is unavoidable.
Scheme 1. Transition-Metal Catalyzed Carbonylative Cross-
Couplings with Organoboranes
Received: February 26, 2020
https://dx.doi.org/10.1021/acs.orglett.0c00736
© XXXX American Chemical Society
Org. Lett. XXXX, XXX, XXX−XXX
A

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Letter
a
Recently, under the assistant of directing groups, many
transition-metal catalyzed cross-coupling reactions involving
inert C-X bonds cleavage have been published.13−16 Inspired
by these works, we think the presence of a directing group at
an appropriate position of aniline is effective, to position the
metal close to the C−N bond, stable the cyclic organometallic
intermediate so that increasing the possibility and rate of
reaction. Moreover, ruthenium plays an important role in the
chelation-assisted inert C-X bond activation cross-coupling
transformations.13a−c,15,16
Based on the above discussions, here we developed an
efficient method on Ru3(CO)12-catalyzed carbonylation of
anilines with arylboronates by the cleavage of neutral aryl C−N
bond (Scheme 1). The pyridine ring has a potent effect on
both reactivity and selectivity on the carbonylation at the C−N
bond in the benzene ring. The present reaction represents the
first, effective catalytic carbonylation reaction of anilines via
cleavage of the neutral aryl C−N bond.
It is known, RuH2(CO)(PPh3)3 is an efficient catalyst for
the cleavage of the inert C(aryl)-O and C(aryl)-N
bonds.13a,15e,f Thus, we first tried the aniline containing
different directing groups, which have been found to promote
C−C bond formation with the regioselective cleavage of the
C−H bond and C−N bond such as ketones (DG 1 and 2),
pyridine (DG 3), pyrazole (DG 4), 2-hydroxypyridine (DG 5),
and oxazole (DG 6), with phenylboronic acid neopentylglycol
esters in the presence of CO atmosphere, using 5 mol %
RuH2(CO)(PPh3)3 as catalyst and o-Xylene as solvent at 140
°C for 20 h. Only pyridine is an efficient directing group gave
the desired ketone in 14% yield by cleavage of the C−N bond.
No byproduct from C−H bond activation could be detected
(Scheme 2).
Table 1. Optimization of the Reaction Conditions
b
Entry
Catalyst
T (°C)
CO (bar)
Yield (%)
1
2
3
4
5
6
7
8
9
[Ru(p-cymene)Cl2]2
RuH2(CO)(PPh3)3
Ru3(CO)12
RuCl3·xH2O
[Rh(cod)Cl]2
[RhCp*Cl2]2
[IrCp*Cl2]2
[PdCp*(cinnamyl)]
Ni(PCy3)2Cl2
Co2(CO)8
Rh6(CO)16
Re2(CO)10
Ru3(CO)12
Ru3(CO)12
Ru3(CO)12
Ru3(CO)12
Ru3(CO)12
140
140
140
140
140
140
140
140
140
140
140
140
140
150
160
160
160
1
1
1
1
1
1
1
1
1
1
1
1
5
5
5
10
10
33
14
44
0
0
0
0
0
0
0
0
0
18
65
61
77(74)
72
c
10
11
12
13
14
15
16
d
17
a
Reaction conditions: 1a (0.20 mmol), boronic ester 2a (0.22 mmol,
1.1 equiv),catalyst (5 mol %), o-Xylene (2 mL), CO, T, 20h. Yield
was determined by gas chromatography(GC) using hexadecane as the
internal standard. 10 mol % Co2(CO)8. 2.5 mol % Ru3(CO)12.
b
c
d
in these cases. We also investigated the solvent effect on the
Ru3(CO)12-catalyzed aryl C−N bond cleavage carbonylation,
and we were pleased to find that the o-Xylene was adequate for
this transformation (see Supporting Information). As we all
know, ligands commonly could enhance the efficiency of the
transition metal catalyst, promoting the conversion of the
reaction. But it is unfavorable in this case (see Supporting
Information). Moreover, under the conditions of 1 bar CO at
140 °C, we find the conversion of 1a is absolutely 100%, and
the main byproduct is the classic cross-coupling product
without CO insertion (Table 1, entry 3). Increasing the CO
pressure could enhance the chemoselectivity of carbonylative
product but inhibit the oxidative addition of 1a, whereas high
temperature can increase the reactivity but not the chemo-
selectivity. Therefore, we studied the reaction at different
temperatures and pressures (Table 1, entries 13−16). Finally,
3a can be obtained in 77% yield at 160 °C under 10 bar of CO
pressure (Table 1, entry 16). In addition, when decreasing the
Ru3(CO)12 to 2.5 mol %, the yield of 3a was also decreased
(Table 1, entry 17).
We also tested various phenylboronic acid derivatives
(Scheme 3). Phenylboroic ester (2a and 2ab) showed better
results than boronic acid (2ac). For the borates, potassium
phenyl trifluoroborate (2ad) produced 3a in 69% yield while
sodium tetraphenylborate (2ae) gave a moderate yield.
Subsequently, a series of phenyl boronic acid neo-
pentylglycol esters were tested under our standard conditions
(Scheme 4). Phenylboronates with alkyl substitutions at ortho-,
para-positions were all well tolerated (3b−3d). 3,5-Disub-
stituted phenylboronate was also transformed into the desired
product in good yield (3e), whereas 2,4,6-trisubstituted
substrate gave a very poor yield (3f, <10% yield) in this case
a
Scheme 2. Directing Groups Effect
a
Reaction conditions: RuH2(CO)(PPh3)3 (5 mol %), 1 (0.2 mmol),
2a (0.22 mmol), o-Xylene (2 mL), CO (1 bar), 140 °C, 20 h,
determined by GC-MS and GC.
Then we selected N,N-dimethyl-2-(pyridin-2-yl) aniline 1a
and phenylboronic acid neopentylglycol ester 2a as the model
substrates, and various commercialized ruthenium catalysts
were tested. With the exception of RuH2(CO)(PPh3)3, [Ru(p-
cymene)Cl2]2 and Ru3(CO)12 could also facilitate this
reaction, and Ru3(CO)12 showed the best result with a 44%
yield (Table 1, entry 3). Some direct coupling (non-
carbonylation) product was formed in these testings as well.
Furthermore, catalytic experiments were carried out using
[Rh(cod)Cl]2, [RhCp*Cl2]2, [IrCp*Cl2]2, [PdCp*-
(cinnamyl)], Ni(PCy3)2Cl2 (entries 5−9), and other carbonyl
metals such as Co2(CO)8, Rh6(CO)16, and Re2(CO)10 (Table
1, entries 10−12); no carbonylation product could be obtained
B
https://dx.doi.org/10.1021/acs.orglett.0c00736
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Scheme 3. Screening of Various Phenylboronic Acid
Derivatives
Scheme 4. Substrate Scope for the Aryl C−N Bond Cleavage
a
a
Carbonylation
a
Reaction conditions: 1a (0.20 mmol), boronic compounds 2 (0.22
mmol, 1.1 equiv), catalyst (5 mol %), o-Xylene (2 mL), CO (10 bar),
160 °C, 20 h, yield was determined by gas chromatography (GC)
using hexadecane as the internal standard.
due to the steric hindrance. The phenylboronates bearing
halogen such as fluoro- (3g), chloro- (3h), and bromo- (3i and
3j) at 3, 4-positions can obtain the desired ketones in good
yields. Similarly, because of the steric hindrance, the phenyl-
boronate with 2-bromo (3k) gave the corresponding ketone in
very poor yield. A range of functionalization groups, such as
TMS (3l), SCH3 (3m), OPh (3n), and trifluoromethyl (3o),
were found to be compatible, as the desired ketones were
obtained in high yields. However, other functional groups like
OMe (3p), CN (3q), ester (3r), and vinyl (3s) only gave the
corresponding ketones in moderate yields. That may be caused
by the coordination properties with metals of these functional
groups. 3-Thiopheneboronic acid neopentyl glycol ester (3t),
as an example of heteroaromatic boronates, with high reactivity
compared to other arylboronates, cannot give the carbonylative
product but obtained the classic C−C coupling product
quantitatively. In addition, naphthalene-2-boronic acid neo-
pentylglycol ester (3u) can give the desired ketone in good
yield as well. The reactivity of other N,N-dimethyl amines were
also investigated. Both alkyl- and halogen-substituted at the 4
or 5 position (3v−3z) reacted with 2a to give the
corresponding ketones in moderate to good yields. Naph-
thalene-2-amine (3ab) showed higher reactivity than aniline,
and the desired ketone was obtained in good yield. Pyrimidine,
frequently replaced with pyridine in catalytic C−H activation
reactions which is also well tolerated (3ac), gave the desired
product in good yield.
Moreover, we examined the influence of various neutral
anilines with different substituents on the N atom under the
optimized conditions (Scheme 5). The anilines bearing a
hydrogen atom is not tolerated in this case, such as
unprotected −NH2 (1ab) and monoalkyl −NHMe (1ac).
Other anilines such as −NEt2 (1ad) and cyclic-pyrrolidine
(1ae) are successful to synthesize the desired ketones. We
investigated the 1-methyl-7-phenylindoline (1af) containing
the cyclo-C(aryl)−N bond as well, and no desired or byproduct
can be found. This may be caused by the effect of the rigid and
planar indoline structure.13b
A plausible reaction pathway is proposed based on the above
results and previous studies (Scheme 6).13b,e First, the
ruthenium catalyst coordinates with 1a. B can be generated
from A through oxidative addition. Meanwhile, the −NMe2
a
Reaction conditions: 1 (0.20 mmol), 2 (0.22 mmol, 1.1 equiv),
Ru3(CO)12 (5 mol %), o-Xylene (2 mL), CO (10 bar), 160 °C, 20 h,
isolated yield.
C
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Scheme 5. Scope of Various C−N Bonds
AUTHOR INFORMATION
Corresponding Author
■
Xiao-Feng Wu − Leibniz-Institut fur Katalyse e.V. an der
̈
̈
Universitat Rostock 18059 Rostock, Germany; orcid.org/
0000-0001-6622-3328; Email: Xiao-Feng.Wu@catalysis.de
Authors
Jian-Xing Xu − Leibniz-Institut fu
̈
r Katalyse e.V. an der
Universitat Rostock 18059 Rostock, Germany
Fengqian Zhao − Leibniz-Institut fur Katalyse e.V. an der
Universitat Rostock 18059 Rostock, Germany
r Katalyse e.V. an der Universitat
̈
̈
̈
̈
̈
Yang Yuan − Leibniz-Institut fu
Rostock 18059 Rostock, Germany
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.orglett.0c00736
Scheme 6. Proposed Mechanism
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We thank the Chinese Scholarship Council for financial
support. We also thank the analytical department of Leibniz-
Institute for Catalysis at the University of Rostock for their
excellent analytical service here.
DEDICATION
■
Dedicated to Professor Pierre H. Dixneuf for his excellent
scientific contributions.
REFERENCES
■
(1) (a) Beller, M. Catalytic Carbonylation Reactions; Springer:
Heidelberg, 2006. (b) Ma, K.; Martin, B. S.; Yin, X.; Dai, M. Natural
product syntheses via carbonylative cyclizations. Nat. Prod. Rep. 2019,
36, 174−219. (c) Peng, J.-B.; Geng, H.-Q.; Wu, X.-F. The Chemistry
of CO: Carbonylation. Chem. 2019, 5, 526−552.
group could coordinate to the boronic compounds which may
further activate the aryl C−N bond.13e After the trans-
metalation and CO insertion, the intermediate D or D′ was
generated. Under the action of CO gas, the final product can
be eliminated and the carbonyl ruthenium will be regenerated
to finish the catalytic cycle.
In summary, an efficient ruthenium(0)-catalyzed carbon-
ylation of neutral anilines through the cleavage of an unreactive
aryl C−N bond has been developed. In the absence of any
ligands and bases, the desired diarylketone can be generated in
moderate to good yields by the cleavage of the neural aryl C−
N bond. And the pyridine ring has a potent effect on both
reactivity and selectivity on the carbonylation at the C−N
bond. Notably, this also represents the first example of
carbonylative coupling of electronically neutral anilines via
C(aryl)−N bond cleavage.
(2) (a) Colquhoun, H. M.; Thompson, D. J.; Twigg, M. V.
Carbonylation; Springer, Boston, MA, 1991. (b) Bertleff, W.; Roeper,
M.; Sava, X. Carbonylation. Ullmann’s Encyclopedia of Industrial
Chemistry; Wiley-VCH: 2007. (c) Arpe, H.-J. Industrial organic
chemistry; Wiley-VCH: Weinheim, 2016.
(3) Nielsen, D. U.; Hu, X.-M.; Daasbjerg, K.; Skrydstrup, T.
Chemically and electrochemically catalysed conversion of CO2 to CO
with follow-up utilization to value-added chemicals. Nat. Catal. 2018,
1, 244−254.
(4) Schoenberg, A.; Heck, R. F. Palladium-catalyzed amidation of
aryl, heterocyclic, and vinylic halides. J. Org. Chem. 1974, 39, 3327−
3331.
(5) (a) Zhao, S.; Mankad, N. P. Metal-catalysed radical carbon-
ylation reactions. Catal. Sci. Technol. 2019, 9, 3603−3613.
̈
(b) Brennfuhrer, A.; Neumann, H.; Beller, M. Palladium-Catalyzed
Carbonylation Reactions of Aryl Halides and Related Compounds.
Angew. Chem., Int. Ed. 2009, 48, 4114−4133. (c) Sumino, S.; Fusano,
A.; Fukuyama, T.; Ryu, I. Carbonylation Reactions of Alkyl Iodides
through the Interplay of Carbon Radicals and Pd Catalysts. Acc. Chem.
Res. 2014, 47, 1563−1574. (d) Friis, S. D.; Lindhardt, A. T.;
Skrydstrup, T. The Development and Application of Two-Chamber
Reactors and Carbon Monoxide Precursors for Safe Carbonylation
Reactions. Acc. Chem. Res. 2016, 49, 594−605. (e) Peng, J.-B.; Wu, F.-
P.; Wu, X.-F. First-Row Transition-Metal-Catalyzed Carbonylative
Transformations of Carbon Electrophiles. Chem. Rev. 2019, 119,
2090−2127.
ASSOCIATED CONTENT
■
sı
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.orglett.0c00736.
(6) (a) Shi, Z.-J. Homogeneous Catalysis for Unreactive Bond
Activation; Wiley: New York, 2014. (b) Ouyang, K.; Hao, W.;
Zhang, W.-X.; Xi, Z. Transition-Metal-Catalyzed Cleavage of C−N
Single Bonds. Chem. Rev. 2015, 115, 12045−12090. (c) Wang, Q.; Su,
General comments, general procedures, analytical data,
and NMR spectra for products (PDF)
D
https://dx.doi.org/10.1021/acs.orglett.0c00736
Org. Lett. XXXX, XXX, XXX−XXX

Organic Letters
pubs.acs.org/OrgLett
Letter
Y.; Li, L.; Huang, H. Transition-metal catalysed C−N bond activation.
Chem. Soc. Rev. 2016, 45, 1257−1272. (d) Tobisu, M.; Chatani, N. In
Inventing Reactions; Gooßen, L. J., Ed.; Springer Berlin Heidelberg:
Berlin, Heidelberg, 2013; pp 35−53. (e) Tobisu, M.; Chatani, N.
Cross-Couplings Using Aryl Ethers via C−O Bond Activation
Enabled by Nickel Catalysts. Acc. Chem. Res. 2015, 48, 1717−1726.
(f) Wencel-Delord, J.; Glorius, F. C−H. bond activation enables the
rapid construction and late-stage diversification of functional
molecules. Nat. Chem. 2013, 5, 369−375. (g) Fujita, T.; Fuchibe,
K.; Ichikawa, J. Transition-Metal-Mediated and -Catalyzed C−F Bond
Activation by Fluorine Elimination. Angew. Chem., Int. Ed. 2019, 58,
390−402.
(7) (a) Rogge, T.; Ackermann, L. Arene-Free Ruthenium(II/IV)-
Catalyzed Bifurcated Arylation for Oxidative C−H/C−H Function-
alizations. Angew. Chem., Int. Ed. 2019, 58, 15640−15645. (b) Shi, H.;
Herron, A. N.; Shao, Y.; Shao, Q.; Yu, J.-Q. Enantioselective remote
meta-C−H arylation and alkylation via a chiral transient mediator.
Nature 2018, 558, 581−585. (c) Lin, Z.; Lan, Y.; Wang, C. Synthesis
of gem-Difluoroalkenes via Nickel-Catalyzed Reductive C−F and C−
O Bond Cleavage. ACS Catal. 2019, 9, 775−780. (d) Fujita, T.;
Fuchibe, K.; Ichikawa, J. Transition-Metal-Mediated and -Catalyzed
C−F Bond Activation by Fluorine Elimination. Angew. Chem., Int. Ed.
2019, 58, 390−402. (e) Tobisu, M.; Xu, T.; Shimasaki, T.; Chatani,
N. Nickel-Catalyzed Suzuki−Miyaura Reaction of Aryl Fluorides. J.
Am. Chem. Soc. 2011, 133, 19505−19511. (f) Shi, S.; Lalancette, R.;
Szostak, R.; Szostak, M. Triflamides: Highly Reactive, Electronically
Activated N-Sulfonyl Amides in Catalytic N−C(O) Amide Cross-
Coupling. Org. Lett. 2019, 21, 1253−1257.
Cleavage. ACS Catal. 2019, 9, 8171−8177. (d) Cao, Z.-C.; Xie, S.-
J.; Fang, H.; Shi, Z.-J. Ni-Catalyzed Cross-Coupling of Dimethyl Aryl
Amines with Arylboronic Esters under Reductive Conditions. J. Am.
Chem. Soc. 2018, 140, 13575−13579. (e) Cao, Z.-C.; Li, X.-L.; Luo,
Q.-Y.; Fang, H.; Shi, Z.-J. Direct Borylation of Tertiary Anilines via
C−N Bond Activation. Org. Lett. 2018, 20, 1995−1998. (f) Zhang, Z.-
B.; Ji, C.-L.; Yang, C.; Chen, J.; Hong, X.; Xia, J.-B. Nickel-Catalyzed
Kumada Coupling of Boc-Activated Aromatic Amines via Non-
directed Selective Aryl C−N Bond Cleavage. Org. Lett. 2019, 21,
1226−1231.
(14) (a) Kakiuchi, F.; Kochi, T.; Murai, S. Chelation-Assisted
Regioselective Catalytic Functionalization of C−H, C−O, C−N and
C−F Bonds. Synlett 2014, 25, 2390−2414. (b) De Sarkar, S.; Liu, W.;
Kozhushkov, S. I.; Ackermann, L. Weakly Coordinating Directing
Groups for Ruthenium(II)-Catalyzed C-H Activation. Adv. Synth.
Catal. 2014, 356, 1461−1479.
(15) (a) Arockiam, P. B.; Bruneau, C.; Dixneuf, P. H. Ruthenium-
(II)-Catalyzed C−H Bond Activation and Functionalization. Chem.
Rev. 2012, 112, 5879−5918. (b) Nareddy, P.; Jordan, F.; Szostak, M.
Recent Developments in Ruthenium-Catalyzed C−H Arylation: Array
of Mechanistic Manifolds. ACS Catal. 2017, 7, 5721−5745. (c) Haito,
A.; Yamaguchi, M.; Chatani, N. Ru3(CO)12-Catalyzed Carbonylation
of C−H Bonds by Triazole-Directed C−H Activation. Asian J. Org.
Chem. 2018, 7, 1315−1318. (d) Ueno, S.; Mizushima, E.; Chatani,
N.; Kakiuchi, F. Direct Observation of the Oxidative Addition of the
Aryl Carbon-Oxygen Bond to a Ruthenium Complex and
Consideration of the Relative Reactivity between Aryl Carbon-
Oxygen and Aryl Carbon-Hydrogen Bonds. J. Am. Chem. Soc. 2006,
128, 16516−16517. (e) Kakiuchi, F.; Usui, M.; Ueno, S.; Chatani, N.;
Murai, S. Ruthenium-Catalyzed Functionalization of Aryl Carbon-
Oxygen Bonds in Aromatic Ethers with Organoboron Compounds. J.
Am. Chem. Soc. 2004, 126, 2706−2707. (f) Zhu, J.; Chen, P.-h.; Lu,
G.; Liu, P.; Dong, G. Ruthenium-Catalyzed Reductive Cleavage of
Unstrained Aryl−Aryl Bonds: Reaction Development and Mecha-
nistic Study. J. Am. Chem. Soc. 2019, 141, 18630−18640. (g) Hu, F.;
Szostak, M. Ruthenium(0)-Catalyzed C−H Arylation of Aromatic
Imines under Neutral Conditions: Access to Biaryl Aldehydes. Org.
Lett. 2016, 18, 4186−4189.
(8) Beller, M.; Wu, X.-F. Transition metal catalyzed carbonylation
reactions; Springer: Heidelberg, 2013.
(9) Ricci, A. Amino Group Chemistry: From Synthesis to the Life
Sciences; John Wiley & Sons: 2008.
(10) (a) Wenkert, E.; Han, A.-L.; Jenny, C.-J. Nickel-induced
Conversion of Carbon-Nitrogen into Carbon-Carbon Bonds. One-
step Transformations of Aryl, Quaternary Ammonium Salts into
Alkylarenes and Biaryls. J. Chem. Soc., Chem. Commun. 1988, 975−
976. (b) Wang, D.-Y.; Kawahata, M.; Yang, Z.-K.; Miyamoto, K.;
Komagawa, S.; Yamaguchi, K.; Wang, C.; Uchiyama, M. Stille
coupling via C−N bond cleavage. Nat. Commun. 2016, 7, 12937.
(16) (a) Koreeda, T.; Kochi, T.; Kakiuchi, F. Cleavage of C−N
Bonds in Aniline Derivatives on a Ruthenium Center and Its
Relevance to Catalytic C-C Bond Formation. J. Am. Chem. Soc. 2009,
131, 7238−7239. (b) Koreeda, T.; Kochi, T.; Kakiuchi, F. Substituent
Effects on Stoichiometric and Catalytic Cleavage of Carbon−
Nitrogen Bonds in Aniline Derivatives by Ruthenium−Phosphine
Complexes. Organometallics 2013, 32, 682−690.
(11) (a) Roglans, A.; Pla-Quintana, A.; Moreno-Manas, M.
̃
Diazonium Salts as Substrates in Palladium-Catalyzed Cross-Coupling
Reactions. Chem. Rev. 2006, 106, 4622−4643. (b) Mo, F.; Dong, G.;
Zhang, Y.; Wang, J. Recent applications of arene diazonium salts in
organic synthesis. Org. Biomol. Chem. 2013, 11, 1582−1593. (c) Saeki,
T.; Son, E.-C.; Tamao, K. Boron Trifluoride Induced Palladium-
Catalyzed Cross-Coupling Reaction of 1-Aryltriazenes with Arenebor-
onic Acids. Org. Lett. 2004, 6, 617−619. (d) Li, W.; Wu, X.-F. N2
Extrusion and CO Insertion: A Novel Palladium-Catalyzed Carbon-
ylative Transformation of Aryltriazenes. Org. Lett. 2015, 17, 1910−
1913.
(12) (a) Basch, C. H.; Liao, J.; Xu, J.; Piane, J. J.; Watson, M. P.
Harnessing Alkyl Amines as Electrophiles for Nickel-Catalyzed Cross
Couplings via C−N Bond Activation. J. Am. Chem. Soc. 2017, 139,
5313−5316. (b) Li, C.-L.; Jiang, X.; Lu, L.-Q.; Xiao, W.-J.; Wu, X.-F.
Cobalt(II)-Catalyzed Alkoxycarbonylation of Aliphatic Amines via
C−N Bond Activation. Org. Lett. 2019, 21, 6919−6923. (c) Jiang, X.;
Zhang, M.-M.; Xiong, W.; Lu, L.-Q.; Xiao, W.-J. Deaminative
(Carbonylative) Alkyl-Heck-type Reactions Enabled by Photocatalytic
C−N Bond Activation. Angew. Chem., Int. Ed. 2019, 58, 2402−2406.
(13) (a) Ueno, S.; Chatani, N.; Kakiuchi, F. Ruthenium-Catalyzed
Carbon−Carbon Bond Formation via the Cleavage of an Unreactive
Aryl Carbon−Nitrogen Bond in Aniline Derivatives with Organo-
boronates. J. Am. Chem. Soc. 2007, 129, 6098−6099. (b) Cong, X.;
Fan, F.; Ma, P.; Luo, M.; Chen, H.; Zeng, X. Low-Valent, High-Spin
Chromium-Catalyzed Cleavage of Aromatic Carbon−Nitrogen Bonds
at Room Temperature: A Combined Experimental and Theoretical
Study. J. Am. Chem. Soc. 2017, 139, 15182−15190. (c) Zhao, Q.;
Zhang, J.; Szostak, M. Ruthenium(0)-Catalyzed Cross-Coupling of
Anilines with Organoboranes by Selective Carbon−Nitrogen
E
https://dx.doi.org/10.1021/acs.orglett.0c00736
Org. Lett. XXXX, XXX, XXX−XXX