One-pot synthesis of benzo[: B] fluorenones via a cobalt-catalyzed MHP-directed [3+2] annulation/ring-opening/dehydration sequence

Article abstract of DOI:10.1039/c9cc00948e

We have developed a one-pot synthesis of benzo[b]fluorenones via a cobalt-catalyzed [3+2] annulation of oxabicyclic alkenes followed by a ring-opening/dehydration sequence in good to excellent yields. With the use of 2-(1-methylhydrazinyl)pyridine (MHP),

Full text of DOI:10.1039/c9cc00948e

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Marilyn M. Olmstead, Alan L. Balch, Josep M. Poblet, Luis Echegoyenet al.
Reactivity differences of Sc3N@C2n (2n 68 and 80). Synthesis of the
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One-pot synthesis of benzo[b]fluorenones via a cobalt-catalyzed
MHP-directed [3+2] annulation/ring-opening/dehydration
sequence
Received 00th January 20xx,
Accepted 00th January 20xx
Shuxian Qiu,a Shengxian Zhai,c Huifei Wang,d Xiaoming Chen,a and Hongbin Zhai*a,b,e
DOI: 10.1039/x0xx00000x
www.rsc.org/
We have developed a one-pot synthesis of benzo[b]fluorenones Rh(III) or Co(III) as the catalyst was described by Bolm and
via a cobalt-catalyzed [3+2] annulation of oxabicyclic alkenes Volla, respectively (Scheme 1b).6b,c Additionally, Volla and
followed by a ring-opening/dehydration sequence in good to coworkers reported a cobalt-catalyzed [4+2] annulation of
excellent yields. With the use of 2-(1-methylhydrazinyl)pyridine phosphinamides with heterobicyclic alkenes using Mn(III) salt
(MHP), first explored by our group as the bidentate directing as the oxidant (Scheme 1b).6d
group in C−H functionalization of benzoic hydrazides, the new
reaction sequence proceeded smoothly and tolerated a wide
Prior work:
a) [3+2] Annulation: Cheng
O
range of functional groups, featuring facile scalability. Notably,
oxygen served as the green oxidant in the reaction system. Careful
tuning of the reaction parameters assured the direct synthesis of
O
O
H
O
Co(II)
Q
Q =
+
N
N
Ag2CO3
H
H
H
b) [4+2] Annulation: Bolm and Volla
O
benzo[b]fluorenones
dihydroepoxybenzofluorenone intermediate.
through
aromatization
of
the
O
NH
O
H
OMe
Rh(III) or Co(III)
+
N
H
H
O
Transition-metal-catalyzed C−H bond functionalization has
been recognized as a powerful tool for rapid construction of
architecturally complex and biologically significant organic
building blocks.1 Recently, C−H bond functionalization with π-
organic components, heterobicyclic alkenes in particular, as
annulation partners has received considerable attention2,3 and
various transformations of heterobicyclic alkenes of this type
have been developed.4,5 In 2016, Cheng and coworkers
developed a Co-catalyzed diastereoselective [3+2] annulation
of amides with bicyclic alkenes directed by 8-aminoquinoline
in the presence of silver oxidant for the synthesis of
dihydroepoxybenzofluorenone derivatives (Scheme 1a).6a
H
R
O
P
Q
H
N
O
R
O
Co(II)
P
Q
N
+
H
Mn(III)
H
O
H
This work:
c) [3+2] Annulation/ring-opening/dehydration
O
O
O
N
Co(II)
O2
+
N
H
N
H
one-pot synthesis
Scheme 1 Overview of the relevant work.
Shortly
thereafter,
a
[4+2]
annulation
of
N-
methoxybenzamides with heterobicyclic alkenes employing
Benzo[b]fluorenones and their corresponding hydrocarbons
are considered as prevalent motifs in bioactive natural
products (Fig. 1). For example, kinafluorenone,7
kinobscurinone,8 stealthins,9 prekinamycin,10 and lomaiviticin
A11 are representative kanamycin-class antibiotics with
intriguing biological activities.12 Typically, classical methods for
the construction of benzo[b]fluorenones featured Friedel–
Crafts-type ring closure of biarylcarboxylic acids and their
derivatives,13 intramolecular cycloaddition,14 or Pd-catalyzed
dehydrogenative cyclization.15 Given the importance of the
benzo[b]fluorenone motifs in pharmaceutics and natural
products, development of a direct and efficient method to
rapidly construct benzo[b]fluorenones remains highly
a. State Key Laboratory of Chemical Oncogenomics and Key Laboratory of Chemical
Genomics, Shenzhen Engineering Laboratory of Nano Drug Slow-Release,
Shenzhen Graduate School of Peking University, Shenzhen 518055, China.
E-mail: zhaihb@pku.edu.cn
b. State Key Laboratory of Applied Organic Chemistry, College of Chemistry and
Chemical Engineering, Lanzhou University, Lanzhou 730000, China.
c. College of Chemistry & Environmental Engineering, Anyang Institute of
Technology, Anyang 455000, China.
d. School of Materials Science and Chemical Engineering, Ningbo University, Ningbo
315211, China.
e. Collaborative Innovation Center of Chemical Science and Engineering, Tianjin
300071, China.
†
Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI: 10.1039/x0xx00000x
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
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conducted under an atmosphere of Ar instead of O2. f ThVeierweaAcrttiicolenOtnimlinee
desirable. As part of our continuing efforts on cobalt-catalyzed
C(sp2)−H annulation reactions of benzoyl hydrazides with π-
was 24 h. g Co(OAc)2 (20 mol %) was added. ND = not detectable.
DOI: 10.1039/C9CC00948E
organic
components
assisted
by
the
2-(1-
yield of 3aa was significantly enhanced to 56% with higher
loading of K2CO3 (4.0 equiv, entry 5). Increasing the amount of
substrate 1a to 2.0 equiv or 2.5 equiv further improved the
yield of 3aa to 72% and 77%, respectively (entries 6 and 7).
Additionally, replacement of K2CO3 with Cs2CO3 further
increased the yield of 3aa to 80% (entry 8). The yield of 3aa
decreased slightly upon lowering the loading of the Co(OAc)2
catalyst to 30 mol % (entry 9). However, increasing the amount
of Cs2CO3 to 5.0 equiv while maintaining Co(OAc)2 at 30 mol %
gave the aromatization product 3aa in 81% yield (entry 10).
Note that the yield of 3aa dropped greatly when Ag2CO3 was
used instead of oxygen as the oxidant (entry 11). And neither
3aa nor 4aa was detected under an atmosphere of Ar (entry
12). Shortening the reaction time to 24 h or lowering the
catalyst loading to 20 mol %6a,18 resulted in lower yields
(entries 13 and 14).
methylhydrazinyl)pyridine (MHP),16 herein we describe a
cobalt-catalyzed C(sp2)–H [3+2] annulation of benzoyl
hydrazides with oxabicyclic alkenes for the one-pot synthesis
of benzo[b]fluorenones (Scheme 1c).17
HO
HO
HO
OH
OH
O
Me
R
Me
O
NH2
N
OR OH
OH
O
OH
O
N
R = CH2OH, stealthin A
R = CHO, stealthin B
R = Me, stealthin C
R = Me, kinafluorenone
R = H, kinobscurinone
prekinamycin
OR1
HO
N2
OR2
O
O
O
H
HO
OH
H
O
O
R2O
O
OR1
N2
OH
O
OH
OMe
O
NMe2
R2
:
R1
:
OH
O
()-lomaiviticin A
O
Co(OAc)2 (30 mol %)
Cs2CO3 (5.0 equiv)
Fig. 1 Representative kanamycin-class antibiotics.
N
R
+
O
N
R
H
TFE (0.1 M), O2
140 °C, 36 h
sealed tube
N
We commenced our investigations on the reaction of N'-
methyl-N'-(2-pyridinyl)benzohydrazide (1a) with 1,4-
1
2a
3
O
3ea
3fa
, R = OCF3, 78%
3aa
3ba
3ca
3da
3ia
3ja
, R =H, 81%
, R = Cl, 84%
, R = Br, 57%
, R = tBu, 67%
epoxydihydronaphthalene (2a), using Co(OAc)2 (40 mol %) as a
catalyst and K2CO3 (2.0 equiv) as a base under oxygen in TFE at
80 °C for 36 h. The reaction generated the desired
benzo[b]fluorenone 3aa in only 4% yield along with
dihydroepoxybenzofluorenone 4aa in 40% yield (Table 1, entry
1). Raising the reaction temperature to up to 140 °C increased
the yield of 3aa to 6~20% (entries 2-4). To our delight, the
, R = Me, 82%
, R = OMe, 56%
, R = OPh, 59%
3ka
, R = I, 75%
3ga
, R = SMe, 72%
, R = Ph, 76%
R
3la
, R = CF3, 76%
3ha
R
O
O
O
O
I
MeO
3ma
3na
3oa
3pa
3qa
3ra
, 78%
O
, R = Me, 63%
, R = OMe, 69%
, R = Cl, 67%
, 63%
, 88%
Table 1 Screening of reaction conditionsa
O
O
O
Cl
MeO
MeO
O
O
N
Co(OAc)2
base
O
H
H
N
Cl
OMe
+
O
N
H
O2, T, 36 h
O
N
H
3sa
3ta
, 88%
, 93%
3va
, 35%
3ua
, 62%
H
4aa
1a
2a
3aa
Scheme 2 Scope of the benzoyl hydrazides.a a Reaction conditions: 1 (0.4 mmol),
2a (0.2 mmol), Co(OAc)2 (30 mol %), Cs2CO3 (5.0 equiv), TFE (2.0 mL), O2 (1 atm),
140 ℃, 36 h, sealed tube.
Entry
1a (equiv)
1.5
Base (equiv)
K2CO3 (2.0)
K2CO3 (2.0)
K2CO3 (2.0)
K2CO3 (2.0)
K2CO3 (4.0)
K2CO3 (4.0)
K2CO3 (4.0)
Cs2CO3 (4.0)
Cs2CO3 (4.0)
Cs2CO3 (5.0)
Cs2CO3 (5.0)
Cs2CO3 (5.0)
Cs2CO3 (5.0)
Cs2CO3 (5.0)
T (ºC) 3aa (%)b 4aa (%)b
1
80
4
40
49
47
48
16
12
4
2
1.5
100
120
140
140
140
140
140
140
140
140
140
140
140
6
With the optimized conditions secured (Table 1, entry 10),
we explored the scope of hydrazides (Scheme 2). Much to our
delight, a range of benzoyl hydrazides bearing either an
3
1.5
9
4
1.5
20
56
72
77
80
74
81
18
ND
63
70
5
1.5
t
electron-donating group (e.g., Me, OMe, OPh, OCF3, Bu, SMe,
6
2.0
Ph) or an electron-withdrawing group (e.g., Cl, Br, I, CF3) at the
para-position of the benzene ring reacted smoothly with 7-
oxabenzonorbornadiene (2a) to form the corresponding
products 3ba-3la in 56-84% yields. meta-Methyl substituted
benzoyl hydrazide afforded benzo[b]fluorenone 3ma in 78%
yield with high regioselectivity. Also, ortho-substituted
hydrazides were competent substrates, providing the desired
products in 63-69% yields (3na-3pa). Multisubstitution (1q-1t)
and more conjugation (1u) of the aryl moiety in the hydrazide
were all well-tolerated, giving the products in good to
excellent yields. Particularly, 3qa was obtained as a single
regioisomer. In addition, heteroaromatic substrate (1v) was
examined, although the desired aromatization product 3va
7
2.5
8
2.0
ND
5
9c
10c
11cd
12ce
13cf
14g
a
2.0
2.0
ND
ND
ND
5
2.0
2.0
2.0
2.0
ND
The reaction was carried out on 0.2 mmol scale, Co(OAc)2 (40
mol %), K2CO3, TFE (2.0 mL), O2, 36 h, sealed tube. b Isolated yield. c
Co(OAc)2 (30 mol %) was added. d Ag2CO3 (2.0 equiv) was used as the
e
oxidant under an atmosphere of N2 rather than O2. The reaction was
2 | J. Name., 2012, 00, 1-3
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was obtained in 35% yield. For the reaction of 2-thiophenyl could be scaled up with comparable yield (75%) under the
View Article Online
DOI: 10.1039/C9CC00948E
hydrazide and that of 3-thiophenyl hydrazide, neither standard conditions (Scheme 4a). To gain more detailed insight
aromatization product 3 nor dihydroepoxy product 4 was into the reaction, relevant experiments were performed
obtained, probably due to potential coordination of the (Schemes 4b/4c). Treating isotopically labelled substrate [D5]-
thiophene sulfur atom with the cobalt that interfered with the 1a with 2a under the standard conditions, no D/H exchange
desired reaction. Note that both of the starting materials was observed, presumably indicating the irreversibility of the
decomposed in these cases.
Next, the scope of 7-oxabenzonorbornadienes was ex- dihydroepoxybenzofluorenone 4aa was subjected to the
amined for the reaction (Scheme 3). 7- standard reaction conditions, ring-opening/dehydration
C–H cobaltation step (Scheme 4b). Furthermore, when
Oxabenzonorbornadienes with electron-donating groups product 3aa was formed in 97% (Scheme 4c-1), suggesting
(methyl or methoxyl) at different positions of the arene all epoxy 4aa might be the precursor of 3aa. Treatment of 4aa
proved to be suitable for the reaction, affording with 2.0 equiv of Cs2CO3 in TFE at 140 °C afforded 3aa in 89%
benzo[b]fluorenones 3bb-3bd in good yields (73–81%). yield (Scheme 4c-2). However, the yield of 3aa dropped at
Alkenes 2e (bearing a 1,3-dioxo unit) and 2f (bearing a lower temperatures. Note that no 3aa was detected in the
naphthyl moiety) were also compatible for this transformation absence of Cs2CO3. These results implied that both the base
and furnished 3be and 3bf in 65 and 68 % yields, respectively. and the reaction temperature were crucial for the ring-
1,4-Dimethyl-1,4-dihydro-1,4-epoxynaphthalene (2g) showed opening/dehydration sequence.
good tolerance and produced 3bg in a comparable yield.
N
O
O
O
N
MHP
R3 R2
O
Co(OAc)2 (30 mol %)
Cs2CO3 (5.0 equiv)
R3
CoII
O2
OH
H
H
O
N
HN
O
R1
R1
N
H
R2
N
N
+
N
TFE (0.1 M), O2
140 °C, 36 h
sealed tube
1a
H
H
R1
O
N
R3
CoIII
H
R3 R2
4aa
R2
R1
D
1b
2
3
Cs2CO3
O
O
O
O
N
O
N
OMe
OCoIII
O
N
HN
N
III
Co
A
OMe
N
H
HO
MeO
E
OMe
C
O
3bb
, 73%
O
3bc
, 73%
3bd
, 81%
O
- H2O
O
O
O
N
III
N
N
2a
Co
O
O
B
O
3bg
3aa
, 65%
3be
, 65%
3bf
, 68%
a
Scheme 3 Scope of the 7-oxabenzonorbornadienes.a Reaction conditions: 1b
(0.4 mmol), 2 (0.2 mmol), Co(OAc)2 (30 mol %), Cs2CO3 (5.0 equiv), TFE (2.0 mL),
O2 (1 atm), 140 ℃, 36 h, sealed tube.
Scheme 5 Proposed mechanism.
Based on our preliminary mechanistic experiments and the
previous reports,6a,19 we proposed a plausible mechanism for
the present reaction (Scheme 5). The reaction is likely to begin
with the oxidation of Co(II) to Co(III) by O2. Chelation of Co(III)
with hydrazide 1a followed by C–H activation produces
intermediate A. Coordination of bicyclic alkene 2a to the Co(III)
center of A from the exo face and the subsequent migratory
insertion of the carbon-carbon double bond into the C–Co
bond furnishes B with a Co-containing seven-membered ring,
which undergoes intramolecular nucleophilic addition followed
by proto-demetalation and elimination of MHP to give
dihydroepoxybenzofluorenone 4aa with simultaneous
regeneration of the Co(III) species. Ring opening occurs in the
presence of Cs2CO3, generating alcohol E, which leads to 3aa
via dehydration.
In summary, we have established a protocol for the one-pot
assembly of benzo[b]fluorenone derivatives through a cobalt-
catalyzed MHP-assisted [3+2] annulation of oxabicyclic alkenes
followed by a ring-opening/dehydration sequence. Careful
tuning of the reaction parameters assured the direct synthesis
of benzo[b]fluorenones through aromatization of the
dihydroepoxybenzofluorenone intermediate. The reaction
features broad substrate scope of both hydrazides and 7-
a) Scalability experiment:
O
O
N
standard conditions
+
O
N
H
N
2a
5 mmol, 721 mg
3aa
862 mg, 75%
1a
b) D/H exchange:
D
O
D
O
D
D
D
D
N
N
H
standard conditions
+
O
N
D
D
3aa
D
1a
2a
[D5]-
[D4]-
(>98% D)
c) Ring-opening/dehydration:
1)
O
O
H
H
standard conditions
O
H
H
4aa
3aa
, 97%
2)
O
O
Cs2CO3 (equiv)
3aa
(%)
T (°C)
H
H
Cs2CO3
89
140
130
120
140
2.0
2.0
2.0
/
72
30
0
TFE, Ar, T, 36 h
sealed tube
O
H
H
4aa
3aa
Scheme 4 Scalability experiment and mechanistic studies.
To demonstrate the synthetic utility of this method, we
carried out the scalability experiment and found the reaction
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5, 2770; (c) S. Prakash, Y.-C. Chang and C.-H. Cheng, Chem.
oxabenzonorbornadienes, and the products were obtained in
good to excellent yields with high regioselectivity. The
methodology allows for rapid access to polynuclear aromatics
with pharmaceutical relevance.
We thank the State Key Basic Research Program of the PRC
(2018YFC0310900), NSFC (21732001, 21871018, 21672017),
Shenzhen Science and Technology Innovation Committee
(JCYJ20150529153646078), Program for Changjiang Scholars
and Innovative Research Team in University (PCSIRT:
IRT_15R28), and “111” Program of MOE for financial support.
View Article Online
Asian J., 2018, 13, 1664.
5
6
(a) Z. Qi and X. Li, Angew. Chem., Int. DEdO.I,: 1200.11033,95/C29,C8C909059;4(8bE)
Y. Unoh, T. Satoh, K. Hirano and M. Miura, ACS Catal., 2015,
5, 6634; (c) L. Kong, S. Yu, G. Tang, H. Wang, X. Zhou and X. Li,
Org. Lett., 2016, 18, 3802; (d) K. Muralirajan, S. Prakash and
C.-H. Cheng, Adv. Synth. Catal., 2017, 359, 513.
(a) P. Gandeepan, P. Rajamalli and C.-H. Cheng, Angew.
Chem., Int. Ed., 2016, 55, 4308; (b) Y. Cheng, K.
Parthasarathy and C. Bolm, Eur. J. Org. Chem., 2017, 2017,
1203; (c) A. Dey, A. Rathi and C. M. R. Volla, Asian J. Org.
Chem., 2018, 7, 1362; (d) R. Nallagonda, N. Thrimurtulu and
C. M. R. Volla, Adv. Synth. Catal., 2018, 360, 255.
M. C. Cone, C. R. Melville, M. P. Gore and S. J. Gould, J. Org.
Chem., 1993, 58, 1058.
S. J. Gould and C. R. Melville, Bioorg. Med. Chem. Lett., 1995,
5, 51.
(a) K. Shin-ya, K. Furihata, Y. Teshima, Y. Hayakawa and H.
Seto, Tetrahedron Lett., 1992, 33, 7025; (b) S. J. Gould, C. R.
Melville, M. C. Cone, J. Chen and J. R. Carney, J. Org. Chem.,
1997, 62, 320.
7
8
9
Conflicts of interest
There are no conflicts to declare.
Notes and references
1
For selected recent reviews on transition-metal-catalyzed C–
H functionalization, see: (a) G. Rouquet and N. Chatani,
Angew. Chem., Int. Ed., 2013, 52, 11726; (b) M. Zhang, Y.
Zhang, X. Jie, H. Zhao, G. Li and W. Su, Org. Chem. Front.,
2014, 1, 843; (c) K. Gao and N. Yoshikai, Acc. Chem. Res.,
2014, 47, 1208. (d) Z. Chen, B. Wang, J. Zhang, W. Yu, Z. Liu
and Y. Zhang, Org. Chem. Front., 2015, 2, 1107; (e) C. Liu, J.
Yuan, M. Gao, S. Tang, W. Li, R. Shi and A. Lei, Chem. Rev.,
2015, 115, 12138; (f) B. Su, Z.-C. Cao and Z.-J. Shi, Acc. Chem.
Res., 2015, 48, 886; (g) L. Yang and H. Huang, Chem. Rev.,
2015, 115, 3468; (h) M. Moselage, J. Li and L. Ackermann,
ACS Catal., 2015, 6, 498. (i) T. Gensch, M. N. Hopkinson and F.
Glorius, Chem. Soc. Rev., 2016, 45, 2900; (j) G. Pototschnig, N.
Maulide and M. Schnürch, Chem. Eur. J., 2017, 23, 9206. (k)
T. Yoshino and S. Matsunaga, Adv. Synth. Catal., 2017, 359,
1245. (l) P. Gandeepan, T. Müller, D. Zell, G. Cera, S. Warratz
and L. Ackermann, Chem. Rev., 2018, 119, 2192.
For selected recent reviews, see: (a) J. Ye and S. Ma, Acc.
Chem. Res., 2014, 47, 989; (b) P. Gandeepan and C.-H. Cheng,
Chem. Asian J., 2015, 10, 824; (c) V. P. Boyarskiy, D. S.
Ryabukhin, N. A. Bokach and A. V. Vasilyev, Chem. Rev., 2016,
116, 5894; (d) P. Gandeepan and C.-H. Cheng, Chem. Asian J.,
2016, 11, 448; (e) M. Gulías and J. L. Mascareñas, Angew.
Chem., Int. Ed., 2016, 55, 11000; (f) W. Ma, P. Gandeepan, J.
Li and L. Ackermann, Org. Chem. Front., 2017, 4, 1435; (g) S.
Prakash, R. Kuppusamy and C.-H. Cheng, ChemCatChem,
2018, 10, 683.
For selected recent reviews, see: (a) M. Lautens, K. Fagnou
and S. Hiebert, Acc. Chem. Res., 2003, 36, 48; (b) D. K.
Rayabarapu and C.-H. Cheng, Acc. Chem. Res., 2007, 40, 971;
(c) F. Wang, S. Yu and X. Li, Chem. Soc. Rev., 2016, 45, 6462.
For selected examples, see: (d) G. C. Tsui, N. M. Ninnemann,
A. Hosotani and M. Lautens, Org. Lett., 2013, 15, 1064; (e) T.
Yang, T. Zhang, S. Yang, S. Chen and X. Li, Org. Biomol.
Chem., 2014, 12, 4290; (f) L. Zhang, C. M. Le and M. Lautens,
Angew. Chem., Int. Ed., 2014, 53, 5951; (g) D. Y. Li, L. L. Jiang,
S. Chen, Z. L. Huang, L. Dang, X. Y. Wu and P. N. Liu, Org.
Lett., 2016, 18, 5134; (h) C. C. J. Loh, M. Schmid, B. Peters, X.
Fang and M. Lautens, Angew. Chem., Int. Ed., 2016, 55, 4600;
(i) Z. Jin, Y. C. Teo, N. G. Zulaybar, M. D. Smith and Y. Xia, J.
Am. Chem. Soc., 2017, 139, 1806; (j) X. Wang, A. Lerchen, T.
Gensch, T. Knecht, C. G. Daniliuc and F. Glorius, Angew.
Chem., Int. Ed., 2017, 56, 1381; (k) X. Wang, Y. Li, T. Knecht,
C. G. Daniliuc, K. N. Houk and F. Glorius, Angew. Chem., Int.
Ed., 2018, 57, 5520.
10 (a) K. S. Feldman and K. J. Eastman, J. Am. Chem. Soc., 2006,
128, 12562; (b) O. Khdour and E. B. Skibo, Org. Biomol.
Chem., 2009, 7, 2140.
11 L. C. Colis, C. M. Woo, D. C. Hegan, Z. Li, P. M. Glazer and S.
B. Herzon, Nat. Chem., 2014, 6, 504.
12 (a) S. J. Gould, Chem. Rev., 1997, 97, 2499; (b) S. B. Herzon
and C. M. Woo, Nat. Prod. Rep., 2012, 29, 87; (c) B. Wang, F.
Guo, J. Ren, G. Ai, B. Aigle, K. Fan and K. Yang, Nat. Commun.,
2015, 6. 7674.
13 (a) H. Koyama and T. Kamikawa, Tetrahedron Lett., 1997, 38,
3973; (b) G. A. Olah, T. Mathew, M. Farnia and G. K. S.
Prakash, Synlett, 1999, 1999, 1067; (c) K.-H. Kim, S.-H. Kim,
K.-Y. Lee and J.-N. Kim, Bull. Korean Chem. Soc., 2011, 32,
1387; (d) D. Sun, B. Li, J. Lan, Q. Huang and J. You, Chem.
Commun., 2016, 52, 3635.
14 (a) Ó. de Frutos and A. M. Echavarren, Tetrahedron Lett.,
1997, 38, 7941; (b) E. González-Cantalapiedra, Ó. de Frutos,
C. Atienza, C. Mateo and A. M. Echavarren, Eur. J. Org.
Chem., 2006, 2006, 1430; (c) J. Zhang, H. Zhang, D. Shi, H. Jin
and Y. Liu, Eur. J. Org. Chem., 2016, 2016, 5545.
2
15 (a) H. Li, R.-Y. Zhu, W.-J. Shi, K.-H. He and Z.-J. Shi, Org. Lett.,
2012, 14, 4850; (b) P. Gandeepan, C.-H. Hung and C.-H.
Cheng, Chem. Commun., 2012, 48, 9379; (c) R. Kishore, S.
Shanthi Priya, M. Sudhakar, B. Venu, A. Venugopal, J. Yadav
and M. L. Kantam, Catal. Sci. Technol., 2015, 5, 3363.
16 (a) S. Zhai, S. Qiu, X. Chen, J. Wu, H. Zhao, C. Tao, Y. Li, B.
Cheng, H. Wang and H. Zhai, Chem. Commun., 2018, 54, 98;
(b) S. Zhai, S. Qiu, X. Chen, C. Tao, Y. Li, B. Cheng, H. Wang
and H. Zhai, ACS Catal., 2018, 8, 6645; (c) H. Zhao, X. Shao, T.
Wang, S. Zhai, S. Qiu, C. Tao, H. Wang and H. Zhai, Chem.
Commun., 2018, 54, 4927; (d) S. Qiu, S. Zhai, H. Wang, C.
Tao, H. Zhao and H. Zhai, Adv. Synth. Catal., 2018, 360, 3271.
(e) R. Mei, N. Sauermann, J. C. A. Oliveira and L. Ackermann,
J. Am. Chem. Soc., 2018, 140, 7913.
17 During the review of this manuscript, Chatani and co-
workers reported a related work on nickle-catalyzed [3+2]
annulation of benzamides with bicylic alkenes assisted by 8-
aminoquinoline, see: A. Skhiri and N. Chatani, Org. Lett.,
2019, DOI: 10.1021/acs.orglett.9b00351.
18 As for the lower yield of 20 mol % of catalyst loading, we
speculate that the 2-(1-methylhydrazinyl)pyridine (MHP)
released from the reaction would reduce the activity of the
Co catalyst by coordination. And both of the starting
materials decomposed under the reaction conditions.
19 (a) X. Wu, K. Yang, Y. Zhao, H. Sun, G. Li and H. Ge, Nat.
Commun., 2015, 6, 6462; (b) J. Zhang, H. Chen, C. Lin, Z. Liu,
C. Wang and Y. Zhang, J. Am. Chem. Soc., 2015, 137, 12990.
3
4
(a) W. Dong, K. Parthasarathy, Y. Cheng, F. Pan and C. Bolm,
Chem. Eur. J., 2014, 20, 15732; (b) H. Cheng, W. Dong, C. A.
Dannenberg, S. Dong, Q. Guo and C. Bolm, ACS Catal., 2015,
4 | J. Name., 2012, 00, 1-3
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