2-(1-Methylhydrazinyl)pyridine as a reductively removable directing group in a cobalt-catalyzed C(sp2)-H bond alkenylation/annulation cascade

Article abstract of DOI:10.1039/c7cc08533h

We describe a new application of 2-(1-methylhydrazinyl)pyridine as a bidentate directing group to directing cobalt-catalyzed C(sp²)-H alkenylation/annulation of the corresponding benzoic hydrazides to form an isoquinoline backbone, via reacting

Full text of DOI:10.1039/c7cc08533h

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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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2-(1-Methylhydrazinyl)pyridine as a Reductively Removable
Directing Group in Cobalt-Catalyzed C(sp2)-H Bond
Alkenylation/Annulation Cascade
Received 00th January 20xx,
Accepted 00th January 20xx
Shengxian Zhai,a Shuxian Qiu,b Xiaoming Chen,b Jiang Wu,a Hua Zhao,b Cheng Tao,a Yun Li,a Bin
Cheng,a Huifei Wangb and Hongbin Zhai*a,b,c
DOI: 10.1039/x0xx00000x
www.rsc.org/
We describe a new application of 2-(1-methylhydrazinyl)pyridine to
as a bidentate directing group to directing cobalt-catalyzed C(sp2)-
NH2•NHMe
H
alkenylation/annulation of the corresponding benzoic
O
H
Me
N
O
H
hydrazides to form an isoquinoline backbone, via reacting with
either a terminal or an internal alkyne followed by annulation. The
N
Cl
H
Cl
N
N
reaction shows
a broad substrate scope with the products
obtained in good to excellent yields and high regioselectivity.
Moreover, the directing group can be reductively removed in one
step under mild conditions.
Criteria of an ideal ligand:
O
Me
N
*
*
inexpensively accessible
N
highly efficient and versatile in C-H
functionalization as a directing group
conveniently removable
M
N
*
Research on transition metal-catalyzed C-H functionalization
has increased significantly over the past decades1 and
emerged as a powerful strategy for efficient and economic
synthesis of complex natural products.2 Control of the site
selectivity is challenging and use of a directing group has
proven to be a common, practical, and powerful strategy. In
2005, Daugulis and coworkers reported a groundbreaking
palladium-catalyzed C(sp3)-H arylation using 8-aminoquinoline
as a bidentate directing group with excellent regioselectivity.3
It was believed that bidentate auxiliaries could generate stable
metallacycle and promote C-H activation. After their
pioneering work, the 8-aminoquinoline was widespreadly
studied and proved to be the most successful and promising
bidentate directing group,4 which set a stage for further
Me
N
O
O
N-N
cleavage
N
NH
N
FG
FG
Scheme 1 Novel bidentate directing group-assisted C-H activation
be rare,6 although it is well-known that the N-X linkage can be
easily cleaved in a traceless fashion compared to the C-N
counterpart. Therefore, it is essential to develop new N-hetero
bond-containing directing groups that are both easily available
and readily removable.
Prior work
(a) 8-Aminoquinolinedirected formal[4+n] cycloaddition14,15
N
O
N
N
O
developing
novel
approaches
to
selective
C-H
O
[Co]
N
N
functionalization. Various new bidentate auxiliaries have been
disclosed over the past a few years,3,5 but most auxiliaries
incorporate a stable C-N linkage that are relatively difficult to
remove. Thus, developing novel removable bidentate directing
groups remains highly desirable. To the best of our knowledge,
the bidentate auxiliaries containing N-X (X = S, N) linkage seem
or
N
H
Ph
+
Ph
Ph
Daugulis's work
Zhang's work
(b) 2-Pyridyl-N-oxide directed formal [4+n] cycloaddition16,17
O
O
O
O
N
[Co]
N
N
O
N
or
N
H
N
O
Ph
+
Ph
Ph
Song's work
Ackermann's work
This work
(c) 2-(1-Methylhydrazinyl)pyridine directed formal [4+2] cycloaddition
N
O
O
O
Me
N
N
e
NH
[Co]
N
Me
N
H
Ph
+
N
Ph
Ph
containinga reductively
cleavable N-N bond
Scheme 2 Cobalt-catalyzed C-H activation
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Table 2 The scope for the alkynesa
In general, transition metal-catalyzed C-H activation relies
mainly on noble metal (such as Ru,7 Rh,8 or Pd9) catalysts. In
spite of their high catalytic activity, these metals are less
abundant in nature. So, it would be economically
advantageous to achieve catalytic C-H activation using more
abundant and lower atomic weight transition metals with
comparable efficacy. Recently, cobalt-catalyzed C-H activation
has attracted considerable attention in its low valence,10
cationic,11 or other forms.12 Because of its high reactivity, low
cost, low toxicity, and abundant availability from the natural
sources, cobalt was considered as an attractive catalyst for C-H
activation.
Based on the considerations mentioned above, we
envisioned that 2-(1-methylhydrazinyl)pyridine might be a
promising bidentate auxiliary candidate,13 since it can be easily
obtained from 2-chloropyridine and methylhydrazine at low
cost. Also, the N-N linkage can be much more easily cleaved
compared to most other bidentate directing groups (Scheme
1). Cobalt-catalyzed C(sp2)-H alkenylation/annulation assisted
by bidentate directing-group was pioneered by Daugulis and
coworkers14, and later flourished by the groups of Zhang15,
Song,16 and Ackermann17 (Schemes 2a, b). Inspired by the
previous studies, we initiated our investigations (Scheme 2c)
on the reaction of N'-methyl-N'-(pyridin-2-yl)benzohydrazide
[a] Reaction conditions:
1
(0.25 mmol), 2n (2.0 equiv),
Co(OAc)2·4H2O (20 mol%), Na2CO3 (2.0 equiv), Mn(OAc)3·2H2O (2.0
equiv), TBAI (2.0 equiv), HFIP (2 mL), 100 oC, air, 24 h. [b] The
reaction performed for 16 h.
either Co(OAc)2·4H2O or Mn(OAc)3·2H2O (entries 6 and 7).
Nevertheless, the reaction could still proceed to some extent
without a base (entry 8).
The scope for the alkynes was next investigated with the
optimal reaction conditions obtained above (see Table 1, entry
5). In general, both electron-rich and electron-deficient alkynes
(
1a) with phenylacetylene (2a), using the catalytic system
reported by Daugulis.14 Gratifyingly, the reaction generated
the desired product 3aa in a moderate yield (Table 1, entry 1),
and the structure of 3aa was determined by an X-ray
diffraction analysis.18 Encouraged by the above results, we
then screened some other bases for the reaction and found
that Na2CO3 and K2CO3 were both slightly better than NaOPiv
(entries 2 and 3). A significant increase of reaction efficiency
was observed when 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP)
was used as the solvent (entry 4). The yield of 3aa was further
increased by incorporation of tetrabutylammonium iodide
(TBAI) as a phase-transfer catalyst into the reaction system
(entry 5).15 In addition, control experiments indicated that the
C-H activation step was completely inhibited in the absence of
were compatible with the reaction (Table 2, 3aa
example, phenylacetylene and 1-ethynyl-4-pentylbenzene
produced nearly equivalent yields (3aa 3af). Phenylacetylenes
with a substituent on the benzene ring such as fluoro (3ag
-3ak). For
,
,
3ah), chloro (3ai), bromo (3aj), and methoxy (3ak) groups
were well tolerated, providing ample opportunities for further
derivatization of the products. 2-Ethynylthiophene (3al) and
ethyl propiolate (3am) were also suitable for this reaction.
Furthermore, internal alkynes such as diphenylacetylene and
its derivatives did not appear to influence the reactions, and
gave the products in moderate to good yields (3an 19
3ao). In
,
the cases of trimethylsilylacetylene (3ap) and cyclopropyl
acetylene (3aq), the corresponding cyclization products were
formed in high yields, yet with relatively low regioselectivities.
Subsequently, a wide range of hydrazides were explored in
the cobalt-catalyzed annulation with alkyne 2n (Table 3).
Benzoic hydrazides containing either an electron-donating or
electron-withdrawing group (e.g., methyl, methoxy, fluoro,
chloro, bromo, or iodo group, in the para-position) on the
Table 1 Substrate scope studiesa
Entry
1
Oxiadnt
Base
NaOPiv
Na2CO3
K2CO3
Na2CO3
Na2CO3
Na2CO3
Na2CO3
/
Solvent
TFE
Yield ( %)b
.
Mn(OAc)3 2H2O
51
61
benzene ring
(3bn-3gn) worked well in this reaction.
.
2
Mn(OAc)3 2H2O
TFE
Moreover, the hydrazide with a para trifluoromethyl group
furnished the product in 72% yield (3hn), indicating that the
reaction might not be very sensitive to the electronic effect. A
single product was generated in an excellent yield of 90% with
the meta-methyl-substituted benzoic hydrazide 3in used as
the substrate, therefore the current reaction might have a
strong steric effect. Indeed, ortho-substituted benzoic
hydrazides with either an electron-donating or an electron-
withdrawing group, gave the corresponding annulation
products in only
.
3
Mn(OAc)3 2H2O
TFE
61
.
4
Mn(OAc)3 2H2O
HFIP
HFIP
HFIP
HFIP
HFIP
84
.
5c
6cd
7c
8c
Mn(OAc)3 2H2O
90
.
Mn(OAc)3 2H2O
N.D.
N.D.
44
/
.
Mn(OAc)3 2H2O
[a] Reaction conditions: 1a (0.25 mmol), 2a (2.0 equiv),
o
Co(OAc)2.4H2O (20 mol%), air, 100 C, 24 h. [b] Isolated yield. [c]
TBAI (2.0 equiv) was added. [d] No cobalt was added.
2 | J. Name., 2012, 00, 1-3
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Table 3 The scope for the hydrazidesa
Co(OAc)2•4H2
O (20 mol%)
O
Me
N
O
Me
N
Mn(OAc)3•2H2O (2.0 equiv)
Na2CO3 (2.0 equiv)
TBAI (2.0 equiv)
N
N
N
+
H
N
HFIP, 100 oC, air, 24 h
Ph
R
R
Ph
2n
1
3
[a] Reaction conditions:
1
(0.25 mmol), 2n (2.0 equiv), Scheme 5 Proposed reaction mechanism
Co(OAc)2·4H2O (20 mol%), Na2CO3 (2.0 equiv), Mn(OAc)3·2H2O (2.0
equiv), TBAI (2.0 equiv), HFIP (2 mL), 100 oC, air, 24 h. [b] The
reaction performed for 16 h.
kinetic isotope effect (KIE) experiment was carried out
between hydrazide 1a and isotopically labelled substrate [D5]-
1a under standard reaction conditions (Scheme 4a), resulting
moderate yields (3jn, 3kn, 3ln). Moreover, for the hydrazide
in a
(for the formation of A) in the catalytic cycle was only slightly
affected by the H/D isotope Furthermore, no H/D exchange
K value of approximately 1.5, suggesting that the first step
with a heteroaromatic moiety 1m, no desired product (3mn
)
was formed at all, even at an elevated reaction temperature.
.
One of the significant merits of the current strategy lies in
the reductive removal of the methylaminopyridine moiety
(originated from the ligand) under mild conditions. For
could be detected in both the reaction of isotopically labelled
substrate [D5]-1a with 2n, and that of 1a with 2n with CD3OD
added as a co-solvent, indicating presumable irreversibility of
the C-H cobaltlation step (Scheme 4b).
instance, upon the N-N bond cleavage through treatment with
o
SmI2 at 0 C to room temperature overnight, compounds 3an
,
3en, and 3fn were transformed smoothly into amides 5–7 in
Based upon our preliminary mechanistic studies and the
relevant literature reports,17,22 we proposed a mechanism for
the cascade reaction sequence (Scheme 5). First, Co(II) is
oxidized to Co(III) by Mn(OAc)3·2H2O. Chelation of Co(III) to
88-94% yields (Scheme 3).20,21
In order to gain further insight into the nature of the present
reaction, the following experiments were performed to
probethe reaction mechanism (Scheme 4). An intermolecular
hydrazide
produces intermediate
Co(III) center within intermediate
1 followed by and subsequent C-H activation
A
. Alkyne
2
is then coordinated to the
to provide intermediate B.
A
Coordinative insertion of the carbon-carbon triple bond into
the C-Co bond of intermediate results in the seven
B
membered intermediate
gives the desired product
C
, reductive elimination of which
3
as well as the low valent Co(I). The
active Co(III) species was regenerated through oxidation of
Co(I) with Mn(OAc)3·2H2O and O2, and the regenerated Co(III)
species enters the next catalytic cycle.
Scheme 3 Reductive removal of the directing group
In conclusion, we have developed an efficient cobalt-
catalyzed C(sp2)-H bond alkenylation
/annulation cascade
reaction of benzoic hydrazides with various terminal or
internal alkynes via a novel 2-(1-methylhydrazinyl)pyridine-
assisted C-H activation, providing a new rapid access to a
series of isoquinoline derivatives. Moreover, the
methylaminopyridine moiety originated from the ligand can be
reductively removed under mild conditions. Further
applications of 2-(1-methylhydrazinyl)pyridine as a bidentate
directing group in other related types of C-H functionalization
and detailed understanding of the mechanisms are currently
being investigated in our laboratory.
We thank the NSFC (21732001, 21672017, 21472072,
21290183), Shenzhen Science and Technology Innovation
Committee
(JCYJ20150529153646078,
JSGG20160229150510483), Program for Changjiang Scholars
Scheme 4 Preliminary mechanistic studies
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2687-2690. (d) K. Muralirajan, K. Parthasarathy and C.-H.
Cheng, Org. Lett., 2012, 14, 4262-4265.
and Innovative Research Team in University (PCSIRT:
IRT_15R28), and “111” Program of MOE for financial support.
8
For selected reviews on Rh-catalyzed C-H activations, see: (a)
G. Song and X. Li, Acc. Chem. Res., 2015, 48, 1007-1020. (b)
B. Ye and N. Cramer, Acc. Chem. Res., 2015, 48, 1308-1318.
(c) D. Colby, A. Tsai, R. Bergman and J. Ellman, Acc. Chem.
Res., 2012, 45, 814-825. (d) J. Lewis, R. Bergman and J.
Ellman, Acc. Chem. Res., 2008, 41, 1013-1025. (e) G. Song, F.
Wang and X. Li, Chem. Soc. Rev., 2012, 41, 3651-3678. (f) D.
Colby, R. Bergman and J. Ellman, Chem. Rev., 2010, 110, 624-
655.
For selected reviews, see: (a) Y. Minami and T. Hiyama, Acc.
Chem. Res., 2016, 49, 67-77. (b) N. Ca’, M. Fontana, E. Motti
and M. Catellani, Acc. Chem. Res., 2016, 49, 1389-1400. (c)
O. Baudoin, Acc. Chem. Res., 2017, 50, 1114-1123. (d) O.
Notes and references
1
For selected reviews on C-H activation, see: (a) K. M. Engle,
T.-S. Mei, M. Wasa and J.-Q. Yu, Acc. Chem. Res., 2012, 45,
788-802. (b) B. Su, Z.-C. Cao and Z.-j. Shi, Acc. Chem. Res.,
2015, 48, 886-896. (c) V. Ritleng, C. Sirlin and M. Pfeffer,
Chem. Rev., 2002, 102, 1731-1769. (d) I. Mkhalid, J. Barnard,
T. Marder, J. Murphy and J. Hartwig, Chem. Rev., 2010, 110,
890-931. For selected examples on C-H activation, see: (a) C.-
Z. Luo, P. Gandeepan, Y.-C. Wu, C.-H. Tsai and C.-H. Cheng,
ACS Catal., 2015, 5, 4837-4841. (b) W. Liu and L. Ackermann,
ACS Catal., 2016, 6, 3743-3752. (c) L.-C. Liang, P.-S. Chien and
Y.-L. Huang, J. Am. Chem. Soc., 2016, 128, 15562-15563. (d) J.
Norinder, A. Matsumoto, N. Yoshikai and E. Nakamura, J.
Am. Chem. Soc., 2008, 130, 5858-5859. (e) J. Park, J. Lee and
S. Chang, Angew. Chem. Int. Ed., 2017, 56, 4256-4260.
For selected examples, see: (a) J. Johnson, N. Li and D.
Sames, J. Am. Chem. Soc., 2002, 124, 6900-6903. (b) S.
O’Malley, K. Tan, A. Watzke, R. Bergman and J. Ellman, J. Am.
Chem. Soc., 2005, 127, 13496-13497. (c) H. Davies, X. Dai and
M. Long, J. Am. Chem. Soc., 2006, 128, 2485-2490. (d) W.
Gutekunst and P. Baran, J. Am. Chem. Soc., 2011, 133,
19076-19079. (e) D.-H. Wang and J.-Q. Yu, J. Am. Chem. Soc.,
2011, 133, 5767-5769. (f) B. Wang, Y. Liu, R. Jiao, Y. Feng, Q.
Li, C. Chen, L. Liu, G. He and G. Chen, J. Am. Chem. Soc.,
2016, 138, 3926-3932.
9
Daugulis, H.-Q. Do and D. Shabashov, Acc. Chem. Res., 2009
42, 1074-1086.
,
10 (a) K. Gao and N. Yoshikai, Acc. Chem. Res., 2014, 47, 1208-
1219. (b) P. Gandeepan and C.-H. Cheng, Acc. Chem. Res.,
2015, 48, 1194-1206. (c) W. Song and L. Ackermann, Angew.
Chem. Int. Ed., 2012, 51, 8251-8254. (d) X. Cong, S. Zhai and
X. Zeng, Org. Chem. Front., 2016, 3, 673-677.
11 (a) J. Hummel and J. Ellman, J. Am. Chem. Soc., 2015, 137,
490-498. (b) Y. Suzuki, B. Sun, K. Sakata, T. Yoshino, S.
Matsunaga and M. Kanai, Angew. Chem. Int. Ed., 2015, 54,
9944-9947. (c) R. Mei, J. Loup and L. Ackermann, ACS. Catal.,
2016, 6, 793-797. (d) Q. Lu, S. Vásquez-Céspedes, T. Gensch
and F. Glorius, ACS. Catal., 2016, 6, 2352-2356.
12 For selected examples, see: (a) P. Gandeepan, P. Rajamalli
and C.-H. Cheng, Angew. Chem. Int. Ed., 2016, 55, 4308-4311.
(b) W. Ma and L. Ackermann, ACS. Catal., 2015, 5, 2822-
2825. (c) D. Kalsi and B. Sundararaju, Org. Lett., 2015, 17,
6118-6121. (d) O. Planas, C. Whiteoak, A. Company and X.
Ribas, Adv. Synth. Catal., 2015, 357, 4003-4012.
13 For 2-hydrazinylpyridine applied to direct C-H activation in
hydrazones, see: (a) S. Zhou, M. Wang, L. Wang, K. Chen, J.
Wang, C. Song and J. Zhu, Org. Lett., 2016, 18, 5632-5635. (b)
Y. Xu, M. Young and G. Dong, J. Am. Chem. Soc., 2017, 139,
5716-5719.
14 (a) L. Grigorjeva and O. Daugulis, Angew. Chem. Int. Ed.,
2014, 53, 10209-10212. (b) T. Nguyen, L. Grigorjeva and O.
Daugulis, ACS. Catal., 2016, 6, 551-554.
15 J. Zhang, H. Chen, C. Lin, Z. Liu, C. Wang and Y. Zhang, J. Am.
Chem. Soc., 2015, 137, 12990-12996.
16 L.-B. Zhang, X.-Q. Hao, Z.-J. Liu, X.-X. Zheng, S.-K. Zhang, J.-L.
Niu and M.-P. Song, Angew. Chem. Int. Ed., 2015, 54, 10012-
10015.
17 R. Mei, H. Wang, S. Warratz, S. Macgregor and L. Ackermann,
Chem. Eur. J., 2016, 22, 6759-6763.
18 The structure of compound 3aa was confirmed by X-ray
crystallography. The CCDC number is: 1547832. Data can be
obtained free of charge from the Cambridge Crystallographic
Data Centre.
19 The structure of compound 3an was confirmed by X-ray
crystallography. The CCDC number is: 1548078. Data can be
obtained free of charge from the Cambridge Crystallographic
Data Centre.
20 C.-Q. Wang, L. Ye, C. Feng and T.-P. Loh, J. Am. Chem. Soc.,
2017, 139, 1762-1765.
21 Application of a lower amount of SmI2 resulted in much
lower yield of the product although the unreacted starting
material could be recovered.
2
3
4
V. Zaitsev, D. Shabashov and O. Daugulis, J. Am. Chem. Soc.,
2005, 127, 13154-13155.
For selected examples, see: (a) Z. Liu, Y. Wang, Z. Wang, T.
Zeng, P. Liu and K. M. Engle, J. Am. Chem. Soc., 2017, 139,
11261-11270. (b) H. M. Omer and P. Liu, J. Am. Chem. Soc.,
2017, 139, 9909-9920. (c) K. Shibata, S. Natsui and N. Chatani,
Org. Lett., 2017, 19, 2234-2237. (d) L. Ilies, Y. Itabashi, R.
Shang and E. Nakamura, ACS. Catal., 2017, 7, 89-92. (e) B.
Wang, C. Lu, S.-Y. Zhang, G. He, W. A. Nack and G. Chen, Org.
Lett., 2014, 16, 6260-6263. (f) K. Takamatsu, K. Hirano and M.
Miura, Angew. Chem. Int. Ed., 2017, 56, 5353-5357. (g) N.
THrimurtulu, A. Dey, D. Maiti and C. M. R. Volla, Angew.
Chem. Int. Ed., 2016, 55, 12361-12365.
5
For selected examples, see: (a) D. Shabashov and O.
Daugulis, J. Am. Chem. Soc., 2010, 132, 3965-3972. (b) N.
Hasegawa, V. Charra, S. Inoue, Y. Fukumoto and N. Chatani,
J. Am. Chem. Soc., 2011, 133, 8070-8073. (c) M. Fan and D.
Ma, Angew. Chem. Int. Ed., 2013, 52, 12152-12155. (d) F.-J.
Chen, S. Zhao, F. Hu, K. Chen, Q. Zhang, S.-Q. Zhang and B.-F.
Shi, Chem. Sci., 2013, 4, 4187-4192. (e) Q. Gu, H. H. Al
Mamari, K. Graczyk, E. Diers and L. Ackermann, Angew.
Chem. Int. Ed., 2014, 53, 3868-3871. (f) M. Shang, S.-Z. Sun,
H.-X. Dai and J.-Q. Yu, J. Am. Chem. Soc., 2014, 136, 3354-
3357. (g) Y.-F. Zhang, H.-W. Zhao, H. Wang, J.-B. Wei and Z.-J.
Shi, Angew. Chem. Int. Ed., 2015, 54, 13686-13690. (h) L.-B.
Zhang, X.-Q. Hao, S.-K. Zhang, Z.-J. Liu, X.-X. Zheng, J.-F. Gong,
J.-L. Niu and M.-P. Song, Angew. Chem. Int. Ed., 2015, 54,
272-275. (i) H. M.-F. Viart, A. Bachmann, W. Kayitare and R.
Sarpong, J. Am. Chem. Soc., 2017, 139, 1325-1329. (j) T. Liu, J.
X. Qiao, M. A. Poss and J.-Q. Yu, Angew. Chem. Int. Ed., 2017
56, 10924-10927. (k) R.-Y. Zhu, L.-Y. Liu and J.-Q. Yu, J. Am.
Chem. Soc., 2017, 139, 12394-12397
,
.
22 (a) N. Thrimurtulu, A. Dey, D. Maiti and C. Volla, Angew.
Chem. Int. Ed., 2016, 55, 12361-12365. (b) W. Ma and L.
Ackermann, ACS. Catal., 2015, 5, 2822-2825. (c) C. Kuai, L.
Wang, B. Li, Z. Yang and X. Cui, Org. Lett., 2017, 19, 2102-
2105.
6
7
(a) N. Rodríguez, J. Romero-Revilla, M. Fernández-Ibáñez and
J. Carretero, Chem. Sci., 2013, 4, 175-179. (b) R. Rit, R. Yadav
and A. Sahoo, Org. Lett., 2012, 14, 3724-3727.
(a) L. Ackermann, Acc. Chem. Res., 2014, 47, 281-295. (b) P.
Arockiam, C. Bruneau and P. Dixneuf, Chem. Rev., 2012, 112,
5879-5918. (c) S. Ko, H. Han and S. Chang, Org. Lett., 2003, 5,
4 | J. Name., 2012, 00, 1-3
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DOI: 10.1039/C7CC08533H
A new application of 2-(1-methylhydrazinyl)pyridine as a reductively bidentate directing group to
directing cobalt-catalyzed C(sp2)-H alkenylation/annulation to form isoquinoline backbones.
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