Ruthenium-catalyzed umpolung carboxylation of hydrazones with CO2

Article abstract of DOI:10.1039/c8sc01299g

The first ruthenium-catalyzed umpolung carboxylation of hydrazones with CO₂ to generate important aryl acetic acids is reported. Besides aldehyde hydrazones, a variety of ketone hydrazones, which have not been successfully applied in previous umpolung reactions with other reactive electrophiles, also show high reactivity and selectivity under mild conditions. Moreover, this operationally simple protocol features good functional group tolerance, is readily scalable, and offers easy derivation of important structures, including bioactive felbinac and adiphenine. Computational studies reveal that this umpolung reaction proceeds through the generation of a Ru-nitrenoid followed by concerted [4 + 2] cycloaddition with CO₂.

Full text of DOI:10.1039/c8sc01299g

View Article Online
View Journal
Chemical
Science
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: S. Yan, L. Zhu, J.
Ye, Z. Zhang, H. Huang, H. Zeng, C. Li, Y. Lan and D. Yu, Chem. Sci., 2018, DOI: 10.1039/C8SC01299G.
This is an Accepted Manuscript, which has been through the
Volume
7 Number 1 January 2016 Pages 1–812
Royal Society of Chemistry peer review process and has been
accepted for publication.
Chemical
Science
Accepted Manuscripts are published online shortly after
www.rsc.org/chemicalscience
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 2041-6539
EDGE ARTICLE
Francesco Ricci et al.
Electronic control of DNA-based nanoswitches and nanodevices
rsc.li/chemical-science

Please do not adjust margins
Page 1 of 5
Chemical Science
View Article Online
DOI: 10.1039/C8SC01299G
Journal Name
ARTICLE
Ruthenium-catalyzed umpolung carboxylation of hydrazones with
CO2
Received 00th January 20xx,
Accepted 00th January 20xx
Si-Shun Yan,a Lei Zhu,b Jian-Heng Ye,a Zhen Zhang,a He Huang,a Huiying Zeng,c Chao-Jun Li,*c,d Yu
Lan,*b and Da-Gang Yu*a,e
DOI: 10.1039/x0xx00000x
The first ruthenium-catalyzed umpolung carboxylation of hydrazones with CO2 to generate important aryl acetic acids is
reported. Besides aldehyde hydrazones, a variety of ketone hydrazones, which have not been successfully applied in
previous umpolung reactions with other reactive electrophiles, also show high reactivity and selectivity under mild
conditions. Moreover, this operationally simple protocol features good functional group tolerance, is readily scalable, and
offers easy derivation to important structures, including bioactive Felbinac and Adiphenine. Computational studies reveal
that this umpolung proceeds through generation of Ru-nitrenoid and then concerted [4+2] cycloaddition with CO2.
www.rsc.org/
Introduction
Carbon dioxide (CO2) has attracted significant attention as an
ideal C1 source due to its high abundance, low cost, low
toxicity and renewability.1 In numerous chemical
transformations involving CO2,2 the synthesis of carboxylic
acids through C─C bond formation is highly promising.3-5 Given
that aryl acetic acids are present in myriad natural products,
agrochemicals and drugs (Figure 1),6 great effort has been
devoted to synthesis of this motif following various
strategies.7,8 Notably, the transition metal-catalyzed reductive
carboxylation of benzyl (pseudo)halides with CO2 has been
well documented by Martin and He (Scheme 1a).8 However,
the Ru-catalyzed carboxylation with CO2 has rarely been
investigated and very limited success has been achieved.9
Figure 1 Aryl acetic acid-containing drugs.
Herein, we report
a
novel Ru-catalyzed umpolung
carboxylation of hydrazones with CO2 under mild conditions
(Scheme 1b). This reaction features good functional group
tolerance, high selectivity, broad substrate scope and facile
scalability.
An umpolung strategy creates new reactivity by reversing
the inherent polarity of common functional groups and
consequently allowing for new reactions with distinct bond
Scheme 1 Synthesis of aryl acetic acids with CO2.
formations.10 Recently, transition-metal-free umpolung
carboxylations of imines and derivatives with CO2 have been
well developed by Sato, Radosevich and Zhang to generate α-
amino acids.11 In 2015, an elegant base-promoted Shapiro-
type carboxylation of N-Tosylhydrazones to generate acrylic
acids was reported by Cheng (Scheme 1b).12 However, there is
no report to generate important aryl acetic acids via cleavage
of C=N double bonds with a catalytic system. As part of our
continuing interest in advancing sustainable organic synthesis
with CO2,13 we wondered whether the transiton metal-
catalysis could resolve such a challenge with different reaction
mechanisms. Recently, one of us has developed the Ru-
catalyzed umpolung reactions with carbonyls as carbanion
equivalents.14 Considering that hydrazones are easily prepared
from carbonyl compounds, which are widely existed in nature
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
Chemical Science
Page 2 of 5
ARTICLE
Journal Name
and industry, this new strategy promises to be more electron-donating and electron-withdrawing groups on the
View Article Online
sustainable and efficient for the synthesis of phenylacetic acids, phenyl ring were compatible. Different sDuObIs:t1i0tu.1e03n9t/sCa8tSCv0a1r2i9o9uGs
especially for complex examples. At the outset of our positions on the arenes, including a bulky trifluoromethyl
investigations, however, it was unclear whether such a group at the ortho position (2r), did not hamper the reaction.
procedure could ever be implemented, since Ru-assisted Remarkably, a variety of functional groups, such as fluoro (2b),
Wolff–Kishner reduction15 takes place smoothly under mild chloro (2c and 2l), bromo (2d
,
2m and 2p), iodo (2e and 2q),
2j and 2k), ester (2i), nitro (2n), and cyano (2o),
generated from the hydrazones. Moreover, a possible side were all tolerated, providing possibility for further
reaction of base-promoted Shapiro-type carboxylation of transformations. Moreover, different kinds of fused rings (2s
reaction conditions. Azine byproduct could also be easily ether (2g
,
a
,
ketone hydrazones to acrylic acids may occur to compete with 2t and 2u
)
and heterocycles, such as thiophene,
our designed reactions.12
benzothiophene and indole (2v 2w and 2x), were compatible
,
in this reaction. It is worth noting that pharmaceutical agent
Felbinac (2f) and a known plant growth stimulant (2w) both
were prepared readily and in a good yield with our strategy.
Table 2 Substrate scope of (hetero)arylaldehyde hydrazonesa
Results and discussion
With these challenges in mind, we began our study by
evaluating the reaction of benzaldehyde hydrazone 1a with
CO2 (Table 1). To our delight, we found that many diphosphine
ligands could promote this reaction (entries 1-3) and dppf gave
the best result (entry 3), which might arise from higher
nucleophilicity of the in-situ generated Ru-complex. We also
tested a variety of bases and found that inorganic bases were
superior to organic bases in this reaction (entries 3-6).
Increasing or decreasing the amount of base gave a lower yield
(entries 7-8). CsF served as an efficient additive to enhance
yield (entry 11), which might arise from enhanced
nucleophilicity with fluoride anion as a strong hydrogen bond
acceptor. Control experiment demonstrated that the Ru-
catalyst was vital to this transformation (entry 12) and that
both ligand and base were important (entries 9-10). No
desired product was detected in the absence of CO2 (entry 13).
Table 1 Optimization of the Reaction Conditionsa
a
Reaction conditions:
1 (0.4 mmol), 1 atm of CO2, [Ru(p-cymene)Cl2]2
(0.008 mol), dppf (0.016 mmol), Cs2CO3 (0.52 mmol), CsF (0.16 mmol), DMF
(2 mL), 80 C, 24 h; isolated yields.
Table 3 Substrate scope of ketone hydrazonesa
Entry
Ligand
Base
Yieldb (%)
Cs2CO3
Cs2CO3
Cs2CO3
K3PO4
KOtBu
DBU
44
19
1
2
dppp
dppe
dppf
dppf
dppf
dppf
dppf
dppf
85 (83)
51
3
4
80
5
27
6
7c
8d
9
Cs2CO3
Cs2CO3
Cs2CO3
no
73
72
13
no
dppf
dppf
dppf
dppf
31
10
11e
12f
13g
Cs2CO3
Cs2CO3
Cs2CO3
78
N.D.
N.D.
a Reaction conditions: 1a (0.4 mmol). b Yields were determined by crude H
1
NMR using dibromomethane as an internal standard, and the isolated
c
d
e
yields are given in parentheses. Base (0.4 mmol). Base (0.6 mmol). No
CsF.
f
g
No [Ru(p-cymene)Cl2]2.
N2 instead of CO2. DBU = 1,8-
Diazabicyclo[5.4.0]undec-7-ene. N. D. = not detected.
a
b
The same reaction conditions as Table 2; isolated yields. Using KOtBu
(1.5 equiv) instead of Cs2CO3 (1.3 equiv) as base.
With the optimized reaction conditions in hand, we then
tested the scope of aldehyde hydrazones (Table 2), most of
which were prepared from the corresponding aldehyde in one
step and used without further purification, thus representing a
Given that -substituted phenylacetic acids are present in
a large collection of bioactive molecules, we wondered
whether our procedure could be extended to ketone
hydrazones, which have not been successfully applied in
previous umpolung reactions with other reactive
significant advantage from
a practical standpoint. Both
2 | J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 3 of 5
Chemical Science
Please do not adjust margins
Journal Name
ARTICLE
electrophiles.14 Although Wolff–Kishner reduction was energy barrier of 23.9 kcal/mol, to generate the amino-Ru
View Article Online
DOI: 10.1039/C8SC01299G
anticipated, we were delighted to discover that benzophenone intermediate C. Subsequently, the second step deprotonation
hydrazone reacted smoothly to give the diphenylacetic acid 4a occurs rapidly with the assistance of Cs2CO3, leading to the
in 72% or 86% yield with minor modification of the reaction formation of Ru-nitrenoid intermediate
conditions (Table 3). Furthermore, the substrates with
D.
different substituents, including fluoro, chloro, and methoxyl,
afforded the desired products in moderate to good yields (4b-
4h). Besides the benzophenone hydrazones, readily-available
ketone hydrazones 3i and 3j furnished the corresponding
-
alkylphenylacetic acid products in synthetically useful yields,
showing the further utility of this process.
To further demonstrate the utility of this umpolung
carboxylation, we conducted a gram-scale synthesis of 3-
bromophenylacetic acid 2m in 83% yield (Scheme 2). An
antihyperlipidemic drug, Fenofibrate 3k’, could be subjected to
this method to produce the acid 4k in 60% isolated yield.
Moreover, the product 4a was readily converted in one step to
Adiphenine (
antiproliferative agent
5
), an inhibitor of nicotinic receptor.16a The
and the known histone deacetylase
6
inhibitor
7 were efficiently accessed by respective amidations
in good yields (see ESI for details).16b-d
Figure 2 Proposed mechanism.
After the formation of Ru-nitrenoid
D
, in Path-A (Figure 3),
the six-membered Ru-cycle complex
E was obtained through
an intermolecular hetero-[4+2] cycloaddition with CO2, with a
free energy barrier of 22.4 kcal/mol.19 The subsequent C–N
bond cleavage leads to the generation of benzylruthenium
intermediate F, which is exergonic by 34.1 kcal/mol as a result
of N2 release. The phenylacetate 14 was then released after
following protonation-ligand exchange, and the active catalyst
B
was also concomitantly regenerated. Meanwhile, the
calculation of Path-B has also been conducted. The
isomerization of Ru-nitrenoid intermediate could afford the
diazoalkane-coordinated Ru complex , which is endergonic by
13.0 kcal/mol. The subsequent carbenation could proceeds
rapidly to afford the Ru-carbenoid with an energy barrier of
1.8 kcal/mol. CO2 insertion via transition state 17-ts then
generates the common benzylruthenium intermediate . The
overall activation free energy of Path-B is determined to be
26.6 kcal/mol, which is 4.2 kcal/mol higher than that of [4+2]
cycloaddition step in Path-A. Therefore, the carbenation
pathway (Path-B) turns out to be unfavorable in comparison
with Path-A.
Scheme 2 Gram-scale synthesis and transformations.
On the basis of preliminary mechanistic studies and
previous reports,14 a plausible mechanism is proposed to
account for this transformation. As shown in Figure 2, catalyst
D
G
A
could be generated (see ESI for details) and undergoes ligand
exchange with hydrazone and Cs2CO3 to give complex , which
undergoes two steps deprotonation to generate Ru-nitrenoid
complex D 17
After a concerted hetero-[4+2] cycloaddition with
CO2, a six-membered Ru-cycle can be formed. Then the
H
B
F
.
E
release of N2, a driving force for this reaction, and following
protonation-ligand exchange provide the desired product and
regenerate the active catalyst
B
.
Alternatively, the
via a sequential
intermediate could also be generated from
F
D
Moreover, Figure 4 shows the variation of the natural bond
orbital (NBO)20 atomic charges on benzylic carbon during
catalytic cycle. It demonstrates that the increasing of the
electron density on benzylic carbon is accompanied by the two
steps N-H cleavage, which clearly indicates that umpolung of
isomerization, carbenation, and CO2 insertion (Path-B).
To further identify the proposed mechanism, density
functional theory (DFT) method M06-L was employed to
investigate this reaction.18 The reactant 1a coordinated Ru
carbonate species
B was considered as a starting complex (see
the reactants. Thus, the Ru-nitrenoid
reactivity with CO2.
D exhibits enhanced
the Figure S1 for details). The first N–H bond cleavage
proceeds via transition state 8-ts (Figure S2), with a free
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Chemical Science
Please do not adjust margins
Page 4 of 5
Journal Name
ARTICLE
View Article Online
DOI: 10.1039/C8SC01299G
Figure 3. Free energy profiles of Path-A (plain) and Path-B (dashed) for the ruthenium-catalyzed carboxylation. The distances are in
angstroms.
Acknowledgements
We thank Prof. Xiaofeng Wu and Prof. Chao Liu for
reproducing the results. We thank Prof. Jason J. Chruma and
Prof. Bi-Jie Li for helpful manuscript revisions. We thank the
National Natural Science Foundation of China (21502124,
21772020, and 21372266), the “973” Project from the MOST
of China (2015CB856600), Recruitment Program of Global
Experts (Short-Term B for C.-J. Li and Young Talents for D.-G.
Yu) and the Fundamental Research Funds for the Central
Universities for financial support.
Notes and references
1
(a) M. Aresta, Carbon Dioxide as Chemical Feedstock, Wiley-
VCH, Weinheim, 2010; (b) L. Ackermann, Angew. Chem., Int.
Ed., 2011, 50, 3842.
Figure 4. Calculated NBO atomic charges on benzylic carbon
during catalytic cycle.
2
(a) T. Sakakura, J.-C. Choi and H. Yasuda, Chem. Rev., 2007,
107, 2365; (b) K. Huang, C.-L. Sun and Z.-J. Shi, Chem. Soc.
Rev., 2011, 40, 2435; (c) M. Cokoja, C. Bruckmeier, B. Rieger,
W. A. Herrmann and F. E. Kühn, Angew. Chem., Int. Ed., 2011,
50, 8510; (d) Y. Tsuji and T. Fujihara, Chem. Commun., 2012,
48, 9956; (e) M. He, Y. Sun and B. Han, Angew. Chem., Int.
Ed., 2013, 52, 9620; (f) L. Zhang and Z. Hou, Chem. Sci., 2013,
Conclusions
In summary, we have realized the first Ru-catalyzed umpolung
carboxylation of hydrazones with CO2 for assembling
important aryl acetic acids under mild conditions. The only
byproduct in this reaction is N2 while overall a high atom
efficiency is realized displaying significant advantages in
carboxylations. Besides aldehyde hydrazones, a variety of
ketone hydrazones, which have not been successfully applied
in previous umpolung reactions with other reactive
electrophiles, also show high reactivity and selectivity in this
reaction. This methodology displays broad substrate scope,
functional groups tolerance, scalability and easy derivation to
important structures. With a deeper understanding of this
reaction, DFT calculation reveals the fundament of this
transformation with generation of Ru-nitrenoid and
intermolecular [4+2] cycloaddition with CO2.
4
, 3395; (g) M. Aresta, A. Dibenedetto and A. Angelini, Chem.
Rev., 2014, 114, 1709; (h) C. Maeda, Y. Miyazaki and T. Ema,
Catal. Sci. Technol., 2014, , 1482; (i) C. S. Yeung and V. M.
Dong, Top. Catal., 2014, 57, 1342; (j) Q. Liu, L. Wu, R.
Jackstell and M. Beller, Nat. Commun., 2015, , 5933; (k) Z.
4
6
Zhang, T. Ju, J.-H. Ye and D.-G. Yu, Synlett, 2017, 28, 741.
For reviews, see: (a) M. Börjesson, T. Moragas, D. Gallego
3
and R. Martin, ACS Catal., 2016, 6, 6739; (b) S. Wang, G. Du
and C. Xi, Org. Biomol. Chem., 2016, 14, 3666; (c) Q. Zhu, L.
Wang, C. Xia and C. Liu, Chin. J. Org. Chem., 2016, 36, 2813;
(d) Q.-W. Song, Z.-H. Zhou and L.-N. He, Green Chem., 2017,
19, 3707; (e) W. Zhang, N. Zhang, C. Guo and X. Lu, Chin. J.
Org. Chem., 2017, 37, 1309; (f) X.-F. Wu and F. Zheng, Top.
Curr. Chem., 2017, 375, 4; (g) J. Luo and I. Larrosa,
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 4
Please do not adjust margins

Page 5 of 5
Chemical Science
Please do not adjust margins
Journal Name
ARTICLE
ChemSusChem, 2017, 10, 3317; (h) Y.-Y. Gui, W.-J. Zhou, J.-H. 10 (a) D. Seebach, Angew. Chem., Int. Ed., 1979, 18, 239; (b) N.
View Article Online
Ye and D.-G. Yu, ChemSusChem, 2017, 10, 1337.
Marion, S. Díez-González and S. P. NolDaOn,I:A10n.g10e3w9./CC8hSeCm01.2, 9In9Gt.
Ed., 2007, 46, 2988; (c) X. Bugaut and F. Glorius, Chem. Soc.
Rev., 2012, 41, 3511; (d) D. M. Flanigan, F. Romanov-
4
For selected examples of carboxylation of electrophiles with
CO2, see: (a) A. Correa and R. Martin, J. Am. Chem. Soc., 2009,
131, 15974; (b) T. Fujihara, K. Nogi, T. Xu, J. Terao and Y. Tsuji,
J. Am. Chem. Soc., 2012, 134, 9106; (c) H. Tran-Vu and O.
Michailidis, N. A. White and T. Rovis, Chem. Rev., 2015, 115
,
9307.
Daugulis, ACS Catal., 2013,
3, 2417; (d) T. Moragas, J. 11 (a) T. Mita, J. Chen, M. Sugawara and Y. Sato, Angew. Chem.,
Cornella and R. Martin, J. Am. Chem. Soc., 2014, 136, 17702;
(e) Y. Liu, J. Cornella and R. Martin, J. Am. Chem. Soc., 2014,
136, 11212; (f) K. Nogi, T. Fujihara, J. Terao and Y. Tsuji,
Chem. Commun., 2014, 50, 13052; (g) X. Wang, Y. Liu and R.
Martin, J. Am. Chem. Soc., 2015, 137, 6476; (h) K. Nogi, T.
Fujihara, J. Terao and Y. Tsuji, J. Org. Chem., 2015, 80, 11618;
Int. Ed., 2011, 50, 1393; (b) T. Mita, J. Chen, M. Sugawara
and Y. Sato, Org. Lett., 2012, 14, 6202; (c) T. Mita, M.
Sugawara, H. Hasegawa and Y. Sato, J. Org. Chem., 2012, 77
,
2159; (d) T. Mita, Y. Higuchi and Y. Sato, Chem.-Eur. J., 2013,
19, 1123; (e) A. A. Sathe, D. R. Hartline and A. T. Radosevich,
Chem. Commun., 2013, 49, 5040; (f) T. Mita, Y. Higuchi and Y.
Sato, Org. Lett., 2014, 16, 14; (g) T. Mita, J. Chen and Y. Sato,
Org. Lett., 2014, 16, 2200; (h) T. Mita, M. Sugawara, K. Saito
and Y. Sato, Org. Lett., 2014, 16, 3028; (i) C.-X. Guo, W.-Z.
Zhang, H. Zhou, N. Zhang and X.-B. Lu, Chem.-Eur. J., 2016,
22, 17156.
(i) T. Mita, Y. Higuchi and Y. Sato, Chem.-Eur. J., 2015, 21
,
16391; (j) M. Börjesson, T. Moragas and R. Martin, J. Am.
Chem. Soc., 2016, 138, 7504; (k) F. Juliá-Hernández, T.
Moragas, J. Cornella and R. Martin, Nature, 2017, 545, 84; (l)
K. Shimomaki, K. Murata, R. Martin and N. Iwasawa, J. Am.
Chem. Soc., 2017, 139, 9467; (m) Q.-Y. Meng, S. Wang and B. 12 S. Sun, J. T. Yu, Y. Jiang and J. Cheng, J. Org. Chem., 2015, 80
König, Angew. Chem., Int. Ed., 2017, 56, 13426. 2855.
For selected examples of carboxylation of nucleophiles with 13 (a) W.-J. Yoo and C.-J. Li, Adv. Synth. Catal., 2008, 350
,
5
,
CO2, see: (a) M. Shi and K. M. Nicholas, J. Am. Chem. Soc.,
1997, 119, 5057; (b) K. Ukai, M. Aoki, J. Takaya and N.
Iwasawa, J. Am. Chem. Soc., 2006, 128, 8706; (c) T. Ohishi, M.
Nishiura and Z. Hou, Angew. Chem., Int. Ed., 2008, 47, 5792;
(d) H. Ochiai, M. Jang, K. Hirano, H. Yorimitsu and K. Oshima,
Org. Lett., 2008, 10, 2681; (e) C. S. Yeung and V. M. Dong, J.
Am. Chem. Soc., 2008, 130, 7826; (f) L. Zhang, J. Cheng, T.
Ohishi and Z. Hou, Angew. Chem., Int. Ed., 2010, 49, 8670; (g)
1503; (b) Z. Zhang, L.-L. Liao, S.-S. Yan, L. Wang, Y.-Q. He,
J.-H. Ye, J. Li, Y.-G. Zhi and D.-G. Yu, Angew. Chem., Int.
Ed., 2016, 55, 7068; (c) J.-H. Ye, L. Song, W.-J. Zhou, T. Ju,
Z.-B. Yin, S.-S. Yan, Z. Zhang, J. Li and D.-G. Yu, Angew.
Chem., Int. Ed., 2016, 55, 10022; (d) Z. Zhang, T. Ju, M.
Miao, J.-L. Han, Y.-H. Zhang, X.-Y. Zhu, J.-H. Ye, D.-G. Yu
and Y.-G. Zhi, Org. Lett., 2017, 19, 396; (e) Y.-Y. Gui, N. Hu,
X.-W. Chen, L.-L. Liao, T. Ju, J.-H. Ye, Z. Zhang, J. Li and D.-
G. Yu, J. Am. Chem. Soc., 2017, 139, 17011; (f) J.-H. Ye, M.
Miao, H. Huang, S.-S. Yan, Z.-B. Yin, W.-J. Zhou and D.-G.
Yu, Angew. Chem., Int. Ed., 2017, 56, 15416. (g) J.-H. Ye, L.
Zhu, S.-S. Yan, M. Miao, X.-C. Zhang, W.-J. Zhou, J. Li, Y. Lan
I. I. F. Boogaerts and S. P. Nolan, J. Am. Chem. Soc., 2010, 132
8858; (h) O. Vechorkin, N. Hirt and X. Hu, Org. Lett., 2010, 12
,
,
3567; (i) K. Nemoto, H. Yoshida, N. Egusa, N. Morohashi and
T. Hattori, J. Org. Chem., 2010, 75, 7855; (j) H. Mizuno, J.
Takaya and N. Iwasawa, J. Am. Chem. Soc., 2011, 133, 1251;
(k) Z. Xin, C. Lescot, S. D. Friis, K. Daasbjerg and T. Skrydstrup,
Angew. Chem., Int. Ed., 2015, 54, 6862; (l) W.-Y. Gao, H. Wu,
and D.-G. Yu, ACS Catal., 2017, 7, 8324. (h) Z.-B. Yin, J.-H. Ye,
W.-J. Zhou, Y.-H. Zhang, L. Ding, Y.-Y. Gui, S.-S. Yan, J. Li and
D.-G. Yu, Org. Lett., 2018, 20, 190. (i) L. Zhu, J.-H. Ye, M.
Duan, X. Qi, D.-G. Yu, R. Bai and Y. Lan, Org. Chem. Front.,
K. Leng, Y. Sun and S. Ma, Angew. Chem., Int. Ed., 2016, 55
,
5472; (m) A. Banerjee, G. R. Dick, T. Yoshino and M. W.
Kanan, Nature, 2016, 531, 215; (n) S. Fenner and L.
Ackermann, Green Chem., 2016, 18, 3804; (o) J. Luo, S. 14 (a) H. Wang, X.-J. Dai and C.-J. Li, Nat. Chem., 2016,
Preciado, P. Xie and I. Larrosa, Chem.-Eur. J., 2016, 22, 6798;
(p) K. Michigami, T. Mita and Y. Sato, J. Am. Chem.
Soc., 2017, 139, 6094.
2018,
Song, J.-H. Ye, J. Li and D.-G. Yu, Chin. J. Chem., 2018, 36, 430.
, 374;
(b) N. Chen, X.-J. Dai, H. Wang and C.-J. Li, Angew. Chem.,
5, 633; (j) Z. Zhang, C.-J. Zhu, M. Miao, J.-L. Han, T. Ju, L.
9
Int. Ed., 2017, 56, 6260; (c) X.-J. Dai, H. Wang and C.-J. Li,
Angew. Chem., Int. Ed., 2017, 56, 6302; (d) W. Wei, X.-J.
Dai, H. Wang, C. Li, X. Yang and C.-J. Li, Chem. Sci., 2017, 8,
6
7
(a) A. L. Blobaum and L. J. Marnett, J. Biol. Chem., 2007, 282
,
16379; (b) J. E. Milne, T. Storz, J. T. Colyer, O. R. Thiel, M.
8193.
Dilmeghani Seran, R. D. Larsen and J. A. Murry, J. Org. Chem., 15 M. E. Furrow and A. G. Myers, J. Am. Chem. Soc., 2004, 126
,
2011, 76, 9519; (c) R. D. Grigg, J. W. Rigoli, R. Van Hoveln, S.
Neale and J. M. Schomaker, Chem.-Eur. J., 2012, 18, 9391.
For selected examples, see: (a) H. L. Finkbeiner and G. D.
Cooper, J. Org. Chem., 1962, 27, 3395; (b) C. M. Williams, J. B.
Johnson and T. Rovis, J. Am. Chem. Soc., 2008, 130, 14936; (c)
M. D. Greenhalgh and S. P. Thomas, J. Am. Chem. Soc., 2012,
134, 11900; (d) P. Shao, S. Wang, C. Chen and C. Xi, Org. Lett.,
2016, 18, 2050; (e) S. Kawashima, K. Aikawa and K. Mikami,
Eur. J. Org. Chem., 2016, 2016, 3166; (f) K. Murata, N.
5436 and references therein.
16 (a) G. Spitzmaul, F. Gumilar, J. P. Dilger, C. Bouzat and Br. J.
Pharmacol., 2009, 157, 804; (b) P. Urbani, M. G. Cascio, A.
Ramunno, T. Bisogno, C. Saturnino and V. D. Marzo, Bioorg.
Med. Chem., 2008, 16, 7510; (c) G. Autore, A. Caruso, S.
Marzocco, B. Nicolaus, C. Palladino, A. Pinto, A. Popolo, M. S.
Sinicropi, G. Tommonaro and C. Saturnino, Molecules, 2010,
15, 2028; (d) B. Ma, Z. Chu, B. Huang, Z. Liu, L. Liu and J.
Zhang, Angew. Chem., Int. Ed., 2017, 56, 2749.
Numasawa, K. Shimomaki, J. Takaya and N. Iwasawa, Chem. 17 (a) J. L. Jat, M. P. Paudyal, H. Gao, Q.-L. Xu, M. Yousufuddin,
Commun., 2017, 53, 3098; (g) V. R. Yatham, Y. Shen and R.
Martin, Angew. Chem., Int. Ed., 2017, 56, 10915; (h) M.
Gaydou, T. Moragas, F. Juliá-Hernández and R. Martin, J. Am.
Chem. Soc., 2017, 139, 12161.
D. Devarajan, D. H. Ess, L. Kurti and J. R. Falck, Science, 2014,
343, 61; (b) V. Bizet, L. Buglioni and C. Bolm, Angew. Chem.,
Int. Ed., 2014, 53, 5639; (c) Y. Lin, L. Zhu, Y. Lan and Y. Rao,
Chem.-Eur. J., 2015, 21, 14937.
8
9
(a) T. León, A. Correa and R. Martin, J. Am. Chem. Soc., 2013, 18 The activation free energy of cycloaddition between amino-
135, 1221; (b) A. Correa, T. León and R. Martin, J. Am. Chem.
Soc., 2014, 136, 1062; (c) S. Zhang, W.-Q. Chen, A. Yu and L.-
ruthenium
which suggests that the second N-H bond cleavage would be
preferentially occur from amino-ruthenium
C and CO2 is up to 38.1 kcal/mol (Figure S3),
N. He, ChemCatChem., 2015,
7
, 3972; (d) T. Moragas, M.
C.
Gaydou and R. Martin, Angew. Chem., Int. Ed., 2016, 55
,
19 For more computaional details, please see in supporting
information.
5053.
L. Wu, Q. Liu, I. Fleischer, R. Jackstell and M. Beller, Nat. 20 A. E. Reed, L. A. Curtiss and F. Weinhold, Chem. Rev., 1988,
Commun., 2014,
5
, 3091.
88, 899.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins