D
B. Shuai et al.
Cluster
Synlett
reactivity with respect to previous work. Preliminary
mechanistic experiments suggest that no radical species are
involved in the product formation.
(a)
N
OR
NiCl2(glyme) (X mol%)
dtbbpy (X mol%)
CN
base (2.0 eq)
DMF (0.2 mL)
rt, 12 h
tBu
tBu
2c
1c
Funding Information
base = (p-MeOC6H4)2Zn, X = 0, NR
LiHMDS, X = 0,
LiHMDS, X = 10,
80% yield
88% yield
This work was financially supported by the Strategic Priority Research
Program of the Chinese Academy of Sciences (Grant XDB20000000),
National Natural Science Foundation of China (Grants 21572245,
21772220, 21821002, and 91956112), and Science and Technology
Commission of Shanghai Municipality (Grant 17JC1401200,
(b)
N
OR
NiCl2(glyme) (0 mol%)
dtbbpy (0 mol%)
CN
tBu
tBu
OR
base (2.0 eq)
DMF (0.2 mL)
rt, 12 h
18JC1415600)
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9
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2)
2n
1n
base = LiHMDS,
NR
Supporting Information
(c)
N
NiCl2(glyme) (0 mol%)
dtbbpy (0 mol%)
Supporting information for this article is available online at
CN
S
u
p
p
orti
n
gInformati
o
n
S
u
p
p
orti
n
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base (2.0 eq)
DMF (0.2 mL)
rt, 12 h
4i
3i
References and Notes
base = LiHMDS,
NR
(1) (a) Kim, D.-S.; Park, W.-J.; Jun, C.-H. Chem. Rev. 2017, 117, 8977.
(b) Souillart, L.; Cramer, N. Chem. Rev. 2015, 115, 9410.
(c) Dermenci, A.; Coe, J. W.; Dong, G. Org. Chem. Front. 2014, 1,
567. (d) Aïssa, C. Synthesis 2011, 3389.
(2) Rubin, M.; Rubina, M.; Gevorgyan, V. Chem. Rev. 2007, 107,
3117.
(d)
N
OR
NiCl2(glyme) (10 mol%)
dtbbpy (10 mol%)
CN
LiHMDS (2.0 eq)
TEMPO (1.0 eq)
DMF (0.2 mL)
rt, 12 h
tBu
tBu
1c
2c, 73%
(3) (a) Boivin, J.; Schiano, A.-M.; Zard, S. Z. Tetrahedron Lett. 1992,
33, 7849. (b) Boivin, J.; Fouquet, E.; Zard, S. Z. J. Am. Chem. Soc.
1991, 113, 1055.
(e)
N
OR
NiCl2(glyme) (10 mol%)
dtbbpy (10 mol%)
CN
LiHMDS (2.0 eq)
TEMPO (1.0 eq)
DMF (0.2 mL)
rt, 12 h
(4) For selected reviews on cycloketone oximes, see: (a) Morcillo, S.
P. Angew. Chem. Int. Ed. 2019, 58, 14044. (b) Stateman, L. M.;
Nakafuku, K. M.; Nagib, D. A. Synthesis 2018, 50, 1569.
(c) Davies, J.; Morcillo, S. P.; Douglas, J. J.; Leonori, D. Chem. Eur.
J. 2018, 24, 12154. (d) Zhao, J.; Duan, X.; Guo, L.-N. Chin. J. Org.
Chem 2017, 37, 2498. (e) Zard, S. Z. Chem. Soc. Rev. 2008, 37,
1603.
(5) For selected examples on ring cleavage of cyclobutanone oximes
via photocatalysis, see: (a) Lu, B.; Cheng, Y.; Chen, L.-Y.; Xiao,
W.-J. ACS Catal. 2019, 9, 8159. (b) He, Y.; Anand, D.; Sun, Z.;
Zhou, L. Org. Lett. 2019, 21, 3769. (c) Xia, P.-J.; Ye, Z.-P.; Hu, Y.-Z.;
Song, D.; Xiang, H.-Y.; Chen, X.-Q.; Yang, H. Org. Lett. 2019, 21,
2658. (d) Zhao, B.; Chen, C.; Lv, J.; Shi, Z. Org. Chem. Front. 2018,
5, 2719. (e) Davies, J.; Sheikh, N. S.; Leonori, D. Angew. Chem. Int.
Ed. 2017, 56, 13361.
(6) For selected examples on ring cleavage of cyclobutanone oximes
via metal catalysis, see: (a) Tang, Y.-Q.; Yang, J.-C.; Wang, L.;
Guo, L.-N. Org. Lett. 2019, 21, 5178. (b) Yang, L.; Zhang, J.-Y.;
Duan, X.-H.; Gao, P.; Jiao, J.; Guo, L.-N. J. Org. Chem. 2019, 84,
8615. (c) Ding, D.; Lan, Y.; Lin, Z.; Wang, C. Org. Lett. 2019, 21,
2723. (d) Liu, Z.; Shen, H.; Xiao, H.; Wang, Z.; Zhu, L.; Li, C. Org.
Lett. 2019, 21, 5201. (e) Ai, W.; Liu, Y.; Wang, Q.; Liu, Q. Org. Lett.
2018, 20, 409. (f) Gu, Y.-R.; Duan, X.-H.; Yang, L.; Guo, L.-N. Org.
Lett. 2017, 19, 5908. (g) Nishimura, T.; Yoshinaka, T.; Nishiguchi,
Y.; Maeda, Y.; Uemura, S. Org. Lett. 2005, 7, 2425.
4a, 69%
3a
Scheme 5 Control experiments
the same time, Pathway A might make a small contribution
to product formation. For 2-alkyl and 3-substituted sub-
strates, the base was not strong enough to remove the -H
atom of the oxime, so the nickel-catalyzed Pathway A is re-
sponsible for product formation.
CN
[Ni]
N
OR
H
Ni
R1
pathway A
R2
R2
R1
Int a'
R2 = Ar
pathway C
base
OR
base
CN
N
CN
Ni
R1
R2
Int b'
R1
R2
R2
R1
Int c
Scheme 6 Proposed reaction mechanism
(7) Nishimura, T.; Uemura, S. J. Am. Chem. Soc. 2000, 122, 12049.
(8) (a) Cao, J.; Chen, L.; Sun, F.-N.; Sun, Y.-L.; Jiang, K.-Z.; Yang, K.-F.;
Xu, Z.; Xu, L.-W. Angew. Chem. Int. Ed. 2019, 58, 897. (b) Zhang,
Z.-Z.; Han, Y.-Q.; Zhan, B.-B.; Wang, S.; Shi, B.-F. Angew. Chem.
Int. Ed. 2017, 56, 13145.
In conclusion, we have developed a nickel-catalyzed Fa-
vorskii-type rearrangement of cyclobutanone oxime es-
ters.14 In the reaction, C−C bond cleavage occurs at the ster-
ically less hindered side, which represents complementary
(9) Murakami, M.; Amii, H.; Ito, Y. Nature 1994, 370, 540.
© 2020. Thieme. All rights reserved. Synlett 2020, 31, A–E