Visible light photoredox-catalyzed alkylation/ring expansion sequences of 1-(1-arylvinyl)cyclobutanol derivatives

Article abstract of DOI:10.1016/j.tetlet.2016.08.047

A visible light-mediated photocatalytic bis(alkoxycarbonyl)methylation/ring expansion of alkenyl cyclobutanols is described. This approach provides a mild and operationally simple access to the synthesis of bis(alkoxycarbonyl)methyl-substituted cyclic ketones from the coupling reaction of 1-(1-arylvinyl)cyclobutanols with aryl bromomalonates.

Full text of DOI:10.1016/j.tetlet.2016.08.047

Accepted Manuscript
Visible light photoredox-catalyzed alkylation/ring expansion sequences of 1-(1-
arylvinyl)cyclobutanol derivatives
Su Jin Kwon, Yeon Joo Kim, Dae Young Kim
PII:
S0040-4039(16)31047-4
DOI:
http://dx.doi.org/10.1016/j.tetlet.2016.08.047
TETL 48018
Reference:
Tetrahedron Letters
To appear in:
Received Date:
Revised Date:
Accepted Date:
6 July 2016
12 August 2016
17 August 2016
Please cite this article as: Kwon, S.J., Kim, Y.J., Kim, D.Y., Visible light photoredox-catalyzed alkylation/ring
expansion sequences of 1-(1-arylvinyl)cyclobutanol derivatives, Tetrahedron Letters (2016), doi: http://dx.doi.org/
10.1016/j.tetlet.2016.08.047
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers
we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and
review of the resulting proof before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Graphical Abstract
To create your abstract, type over the instructions in the template box below.
Fonts or abstract dimensions should not be changed or altered.
Leave this area blank for abstract info.
Visible light photoredox-catalyzed alkylation/
ring expansion sequences of 1-(1-arylvinyl)cyclobutanol derivatives
Su Jin Kwon, Yeon Joo Kim, and Dae Young Kim*

1
Tetrahedron Letters
Visible light photoredox-catalyzed alkylation/ring expansion sequences of 1-(1-
arylvinyl)cyclobutanol derivatives
Su Jin Kwon, Yeon Joo Kim, and Dae Young Kim*
Department of Chemistry, Soonchunhyang University, Asan, Chungnam 336-745, Republic of Korea
ARTICLE INFO
ABSTRACT
A visible light-mediated photocatalytic bis(alkoxycarbonyl)methylation/ring expansion of
alkenyl cyclobutanols is described. This approach provides a mild and operationally simple
access to the synthesis of bis(alkoxycarbonyl)methyl-substituted cyclic ketones from the
coupling reaction of 1-(1-arylvinyl)cyclobutanols with aryl bromomalonates.
Article history:
Received
Received in revised form
Accepted
Available online
2009 Elsevier Ltd. All rights reserved.
Keywords:
Bromomalonates,
Photocatalysis,
Radical reaction,
1,2-Carbon migration
The difunctionalization of alkenes has become a powerful
strategy for the synthesis of useful building blocks of natural
products and biologically active compounds through introduction
of two functional groups across double bond.1 Until now,
considerable studies have been conducted on the
difunctionalization of alkenes with the aim of developing novel
and efficient methods.2 Recently, a novel application of visible
light-mediated photoredox catalysis was described for chemical
transformations in synthetic organic chemistry and has proven to
be a powerful tool with a host of attractive features such as mild
reaction condition, excellent functional group tolerance, and high
reactivity.3 With the use of suitable radical sources, the visible
light-mediated photocatalytic difunctionalization of alkenes
mediated by visible light offers a viable option for obtaining
functionalized molecules.4 Since the pioneer work on the visible
light-induced difunctionalization of alkenes with alkyl radical
species generated from bromomalonates disclosed by Stephenson
As part of a research program related to redox reaction and
cyclization sequences, we recently reported the internal redox
reaction via C-H bond functionalization10 and photoredox-
catalytic
fluoroalkylation/ring
expansion.11
In
this
communication, we wish to describe visible light-mediated
photocatalytic bis(alkoxycarbonyl)methylation/ring expansion
via 1,2-carbon migration of 1-(1-arylvinyl)cyclobutanol
derivatives.
To determine suitable reaction conditions for the visible light-
mediated photocatalytic bis(alkoxycarbonyl)methylation/ring
expansion of 1-(1-arylvinyl)cyclobutanols, we examined the
visible light-mediated photocatalytic reaction of (1-(1-
phenylvinyl)cyclobutoxy)trimethylsilane (1a) with diethyl
bromomalonate (2a) in the presence of 5 mol % of fac-Ir(ppy)3
under visible light irradiation with blue LEDs (5 W, max = 455
nm) in DMF at room temperature (Table 1). By screening
photocatalysts in DMF (entries 1-5), we found that fac-Ir(ppy)3
in 2010,5
a number of photocatalytic systems for the
was
the
best
photocatalyst
for
this
difunctionalization of alkenes with electron-deficient alkyl
bromides have been reported.6 Among the known alkylation
reactions, the introduction of a bis(alkoxycarbonyl)methyl group
(-CH(COOEt)2) is a highly appealing topic owing to the high
possibility for post-functionalization of ester groups.7 Recently,
several groups reported the radical addition and 1,2-aryl
migration sequences of α,α-diaryl allylic alcohol derivatives with
various radicals including phophoryl, sulfonyl, trifluoromethyl,
and alkyl radicals using metal-free oxidation and metal- or photo-
mediated oxidation.8 Quite recently, the Xia group has reported
visible light mediated arylalkylation of α,α-diaryl allylic alcohols
through concomitant 1,2-aryl migration.9 However, to the best of
our knowledge, visible light-mediated photoredox alkylation and
1,2-carbon migration sequences of 1-(1-arylvinyl)cyclobutanols
with bromomalonate derivatives has not been reported.
bis(alkoxycarbonyl)methylation/1,2-carbon migration, affording
the corresponding product 3a in 64% yield (Table 1, entry 1).
Among the solvents evaluated (Table 1, entries 1 and 6-9), the
best result was achieved when the reaction was conducted in
DMSO (Table 1, entry 9). Next, we examined effect of bases in
DMSO (Table 1, entries 9-14). A survey of different bases
indicates that 2,6-lutidine gave the highest yield (Table 1, entry
9). The present catalytic system tolerates photocatalyst loading
down to 3 mol % without compromising the yield. However,
reducing the photocatalyst loading to 1 mol % slightly reduced
the product yield (Table 1, entries 15-16). When a 1-(1-
phenylvinyl)cyclobutanol was utilized as the substrate instead of
1a, reduced yield was obtained (Table 1, entry 17). Without 2,6-
lutidine, a longer reaction time was needed for the complete

2
Tetrahedron
Table 1. Optimization of the reaction conditions a
Table 2. Variation of substrates 1a,b
_____________________________________________________
time
(h)
1
yield
(%)b
64
entry
photocatalyst
base
solvent
1
2
3
4
5
6
7
8
fac-Ir(ppy)3
Ru(bpy)3Cl2∙6H2O
Ru(Phen)3Cl2∙H2O
Fluorecein
2,6-lutidine
2,6-lutidine
2,6-lutidine
2,6-lutidine
DMF
DMF
5
5
n.r.
n.r.
n.r.
n.r.
48
DMF
DMF
5
Eosin Y
2,6-lutidine
2,6-lutidine
DMF
5
fac-Ir(ppy)3
CH2Cl2
CH3CN
THF
1
2,6-lutidine
2,6-lutidine
fac-Ir(ppy)3
12
12
42
fac-Ir(ppy)3
34
9
fac-Ir(ppy)3
fac-Ir(ppy)3
2,6-lutidine
DIPEA
DMSO
DMF
1
9
2
5
5
5
1
3
1
3
3
3
66
n.r.
20
25
22
22
66
62
59
10
11
12
13
14
15c
16d
17e
18
19
20f
fac-Ir(ppy)3
fac-Ir(ppy)3
Et3N
DMF
K2CO3
DMF
fac-Ir(ppy)3
fac-Ir(ppy)3
K2HPO4
DTBMP
2,6-lutidine
2,6-lutidine
2,6-lutidine
-
DMF
___________________________________________________
DMF
a Reaction conditions: (1-(1-arylvinyl)cyclobutoxy)trimethylsilane 1 (0.3
mmol), BrCH2CO2Et (2, 0.6 mmol), 2,6-lutidine (0.6 mmol), fac-Ir(ppy)3
(0.009 mmol), DMSO (5.0 mL) at room temperature under visible light
irradiation. b Isolated yield.
fac-Ir(ppy)3
fac-Ir(ppy)3
fac-Ir(ppy)3
fac-Ir(ppy)3
-
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
In addition to ethyl bromomalonate (4) and ethyl
bromopropionate (6) could undergo photoredox-catalytic
alkylation/ring expansion under optimum reaction conditions.
Furthermore, (1-(1H-inden-3-yl)cyclobutoxy)trimethylsilane (8)
was used as a substrate in this visible light-mediated photoredox
reaction. It was found that the corresponding product 9 was
obtained in 39% yield with 2.6:1 dr (Scheme 1).
58
n.r.
2,6-lutidine
2,6-lutidine
n.r.
fac-Ir(ppy)3
a Reaction conditions: (1-(1-phenylvinyl)cyclobutoxy)trimethylsilane (1a, 0.3
mmol), Br-CH(CO2Et)2 (2, 0.6 mmol), base (0.6 mmol), photocatalyst (0.015
mmol), solvent (5.0 mL) at room temperature under visible light irradiation. b
Isolated yield. 3 mol % photocatalyst loading. 1 mol % photocatalyst
loading. e 1-(1-phenylvinyl)cyclobutanol was utilized as the substrate instead
of 1a. f The reaction was performed in the dark.
c
d
reaction with a slight decrease in yield (Table 1, entry 18). The
control experiment showed that the reaction could not proceeded
in the absence of a photocatalyst and visible light (Table 1,
entries 19-20).
With the optimal reaction conditions in hand, we investigated
the scope of this visible light-mediated photocatalytic
bis(alkoxycarbonyl)methylation/ring expansion via the 1,2-
carbon
migration
sequence
of
(1-(1-
arylvinyl)cyclobutoxy)trimethyl-silanes
1
with
dialkyl
bromomalonate (2) in the presence of 3 mol % of fac-Ir(ppy)3
under light irradiation with blue LEDs in DMSO at room
temperature for 1 h.12 As shown in Table 2, various (1-(1-
arylvinyl)cyclobutoxy)trimethylsilanes
1
with
electron-
withdrawing or electron-donating aryl groups furnished the
corresponding migration products with moderate to good yields
(Table 2, 3a–3g). Additionally, dimethyl malonate (2b) and
diisopropyl malonate (2c) were found to be effective for this
process (Table 2, 3h-3i).
(1-(3-Phenylprop-1-en-2-
Scheme 1. Visible light-mediated photoredox alkylation/ring
expansion of ethyl bromoesters (4 and 6) and cyclobutoxy
trimethylsilane derivatives (1h and 8).
yl)cyclobutoxy)trimethylsilane (1h) as an aliphatic alkene
substrate provided the desired product 3j with 34% yield under
the same reaction conditions (Scheme 1).

3
presence of 3 mol % of fac-Ir(ppy)3. The proposed technique is
To illustrated synthetic utility, we further conducted some
functional group transformation. The cyclopentanone derivative
3i was reduced the corresponding cyclopentanol 10 with 81%
yield and 4:1 diastereoselectivity. Ttreatment of the
cyclopentanone 3b with the N-fluorobenzensulfonimide at the
base conditions led to the formation of the fluorinated ketone 11
in 54% yield (Scheme 2).
an efficient option for synthesizing bis(alkoxycarbonyl)methyl-
substituted cyclic ketone derivatives. A follow-up study is
ongoing involving the asymmetric version of the visible light-
mediated photoredox-catalyzed bis(alkoxycarbonyl)methylation
/ring expansion.
Acknowledgments
This research was supported by the Soonchunhyang
University Research Fund and Basic Science Research Program
through the National Research Foundation of Korea (NRF)
funded by the Ministry of Science, ICT and Future Planning
(2014006224).
References and notes
1.
For selected reviews on the alkene difunctionalization, see: (a)
Yudin, A. K. in Catalyzed Carbon-Heteroatom Bond Formation,
Wiley-VCH, Weinheim, 2010, pp. 119–135; (b) McDonald, R. I. ;
Liu, G.; Stahl, S. S. Chem. Rev. 2011, 111, 2981; (c) Wolfe, J. P.
Angew. Chem. Int. Ed. 2012, 51, 10224; (d) Shimizu, Y. ; Kanai,
M. Tetrahedron Lett. 2014, 55, 3727; (e) Liu, G. Org. Biomol.
Chem. 2012, 10, 6243; (f) Chen, P.; Liu, G. Synthesis 2013, 45,
2919; (g) Chemler, S. R.; Bovino, M. T. ACS Catal. 2013, 3, 1076.
For recent alkene difunctionalization examples, see: (a) Tang, Y.;
Fan, Y.; Gao, H.; Li, X.; Hemric, X. X. Tetrahedron Lett. 2015, 56,
56; (b) Zhang, Z.; Tang, X.; Thomoson, C. S.; Dolbier, W. R. Org.
Lett. 2015, 17, 3528; (c) Thomoson, C. S.; Tang, X.-J.; Dolbier, W.
R. J. Org. Chem. 2015, 80, 1264; (d) Zheng, Y.; He, Y.; Rong, G.;
Zhang, X.; Weng, Y.; Dong, K.; Xu, X.; Mao, J. Org. Lett. 2015,
17, 5444; (e) Lan, X.–W.; Wang, N.–X.; Zhang, W.; Wen, J.-L.;
Bai, C.–B.; Xing, Y.; Li. Y.-H. Org. Lett. 2015, 17, 4460; (f) Sun,
X.; Li, X.; Song, S.; Zhu, Y.; Liang, Y.-F.; Jiao, N. J. Am. Chem.
Soc. 2015, 137, 6059; (g) Zhu, R.; Buchwald, S. L. J. Am. Chem.
Soc. 2015, 137, 8069; (h) Yang, Y.; Liu, Y.; Jiang, Y.; Zhang, Y.;
Vicic, D. A. J. Org. Chem. 2015, 80, 6639; (i) Zhou, S.-F.; Pan, X.;
Zhou, Z.–H.; Shoberu, A.; Zou, J.–P. J. Org. Chem. 2015, 80,
3682; (j) Hemric, B. N.; Shen, K.; Wang, Q. J. Am. Chem. Soc.
2016, 138, 5813; (k) Egami, H.; Yoneda, T.; Uku, M.; Ide, T.;
Kawato, Y.; Hamashima, Y. J. Org. Chem. 2016, 81, 4020; (l)
Banik, S. M.; Medley, J. W.; Jacobsen, E. N. J. Am. Chem. Soc.
2016, 138, 5000; (m) Fu, M.; Chen, L.; Jiang, Y.; Jiang, Z.-X.;
Yang, Z. Org. Lett. 2016, 18, 348; (n) Huo, C.; Wang, Y.; Yuan,
Y.; Chena, F.; Tanga, J. Chem. Commun. 2016, 52, 7233.
Scheme 2. Transformation of cyclopentanone derivatives 3.
To obtain mechanistic insights into this transformation, some
preliminary experiments were performed. The absence of either
the photocatalyst fac-Ir3+(ppy)3 or visible light shut down the
reactivity completely, thus suggesting a crucial role for both of
these elements in the transformation (Table 1, entries 17-18). A
trace of the product was detected in the presence of a radical
scavenger 2,2,6,6-tetramethylpiperidin-1-yloxyl (TEMPO). We
propose the reaction mechanism shown in Figure 1 based on the
results. The presence of visible light induces a metal to ligand
charge transfer in the photocatalyst fac-Ir3+(ppy)3, resulting in the
2.
*
excited state fac-Ir3+(ppy)3 . Afterward, a single electron transfer
to ethyl bromomalonate (2) generates fac-Ir4+(ppy)3 and a
bis(alkoxycarbonyl)methyl radical I. Radical I then reacts with
(1-(1-arylvinyl)cyclobutoxy)trimethylsilanes
1,
yielding
intermediate II, which undergoes single electron transfer from
fac-Ir4+(ppy)3 to generate cation III. 1,2-carbon migration of
cation III leads to a ring expansion that yields the product 3.
3.
For selected reviews of visible-light photoredox catalysis, see: (a)
Narayanam, J. M. R.; Stephenson, C. R. J. Chem. Soc. Rev. 2011,
40, 102; (b) Tucker, J. W.; Stephenson, C. R. J. J. Org. Chem.
2012, 77, 1617; (c) Xuan, J.; Xiao, W-J. Angew. Chem. Int. Ed.
2012, 51, 6828; (d) Maity, S.; Zheng, N. Synlett 2012, 23, 1851; (e)
Xi, Y-M.; Yi, H.; Lei, A-W. Org. Biomol. Chem. 2013, 11, 2387;
(f) Prier, C. K.; Rankic, D.A.; MacMillan, D.W. Chem. Rev. 2013,
113, 5322; (g) Koike, T.; Akita, M. Top. Catal. 2014, 57, 967; (h)
Schultz, D. M.; Yoon, T. P. Science, 2014, 343, 985; (i) Hopkinson,
M. N.; Sahoo, B.; Li, J-L.; Glorius, F. Chem. Eur. J. 2014, 20,
3874; (j) Koike, T.; Akita, M. Inorg. Chem. Front. 2014, 1, 562; (k)
Ravelli, D.; Protti, S.; Fagnoni, M. Chem. Rev. 2016, doi:
10.1021/acs.chemrev.5b00662.
4.
For recent alkene difunctionalization examples with photoredox
catalysis, see: (a) Yasu, Y.; Arai, Y.; Tomita, R.; Koike, T.; Akita,
M. Org. Lett. 2014, 16, 780; (b) Oh, S. H.; Malpani, Y. R.; Ha, N.;
Jung, Y. S.; Han, S. B. Org. Lett. 2014, 16, 1310; (c) Dagousset,
G.; Carboni, A.; Magnier, E.; Masson, G. Org. Lett. 2014, 16,
4340; (d) Guo, W.; Cheng, H-G.; Chen, L-Y.; Xuan, J.; Feng, Z-J.;
Chen, J.-R.; Lu, L-Q.; Xiao, W-J. Adv. Synth. Catal. 2014, 356,
2787; (e) Keshari, T.; Yadav, V. K.; Srivastava, V. P.; Yadav, L. D.
S. Green Chem. 2014, 16, 3986; (f) Tomita, R.; Yasu, Y.; Koike,
T.; Akita, M. Angew. Chem. Int. Ed. 2014, 53, 7144; (g)
Figure 1. Proposed reaction mechanism.
Musacchio, A. J.; Nguyen, L.Q.; Beard, G.H.; Knowles, R. R. J.
Am. Chem. Soc. 2014, 136, 12217; (h) Li, L.; Chen, Q-Y.; Guo, Y.
J. Fluorine Chem. 2014, 167, 79; (i) Carboni, A. Dagousset, G.
Magnier, E. Masson, G. Synthesis 2015, 47, 2439; (j) Noto, N.;
Miyazawa, K.; Koike, T.; Akita, M. Org. Lett. 2015, 17, 3710; (k)
Tang, X.-J.; Zhang, Z.; Dolbier, W. R., Jr. Chem. Eur. J. 2015, 21,
In conclusion, we achieved visible light-mediated
photoredox-catalyzed
expansion through
bis(alkoxycarbonyl)methylation/ring
1,2-carbon migration of (1-(1-
arylvinyl)cyclobutoxy)trimethylsilanes 1 with bromomalonate
(2). The reaction was completed after a short period in the

4
Tetrahedron
18961; (l) Tang, X.-J.; Dolbier, W. R. Angew. Chem. Int. Ed. 2015,
674; (o) Xu, P. Hu, K. Gu, Z. Cheng, Y. Zhu, C. Chem. Commun.
2015, 51, 7222; (p) Sahoo, B.; Li, J.-L.; Glorius, F. Angew. Chem.
Int. Ed. 2015, 54, 11577; (q) Chu, X.-Q.; Meng, H.; Xu, X.-P.; Ji,
S.-J. Chem. Eur. J. 2015, 21, 11359; (r) Yu, J. –T.; Jiang, Y.;
Cheng, J. Org. Biomol. Chem. 2015, 13, 10299; (s) Xu, P. Hu, K.
Gu, Z. Cheng, Y. Zhu, C. Chem. Commun. 2015, 51, 7222; (t)
Bergonzini, G.; Cassani, C.; Lorimer-Olsson, H.; Hörberg, J.;
Wallentin, C.–J. Chem. Eur. J. 2016, 22, 3292; (u) Hu, W.; Sun, S.;
Cheng, J. J. Org. Chem. 2016, 81, 4399.
54, 4246; (m) Li, L.; Huang, M.; Liu, C.; Xiao, J.-C.; Chen, Q.-Y.;
Guo, Y.; Zhao. Z.-G. Org. Lett. 2015, 17, 4714; (n) Wei, Q.; Chen,
J.–R.; Hu, X.–Q.; Yang, X.-C.; Lu, B.; Xiao, W.-J. Org. Lett. 2015,
17, 4464; (o) Arai, Y.; Tomita, R.; Ando, G.; Koike, T.; Akita, M.
Chem. Eur. J. 2016, 22, 1262; (p) Zhang, Q.; Zhang, Z.-Q.; Fu, Y.;
Yu, H.–Z. ACS Catal. 2016, 6, 798; (q) Zhang, M.; Duan, Y.; Li,
W.; Chenga, Y.; Zhu, C. Chem. Commun. 2016, 52, 4761; (r)
Honeker, R.; Garza-Sanchez, A.; Hopkinson, M. N.; Glorius, F.
Chem. Eur. J. 2016, 22, 4395.
9.
Huang, H.-H.; Yan, H.; Yang, C.; Xia, W. Chem. Commun. 2015,
51, 4910.
5.
(a) Tucker, J. W.; Nguyen, J. D.; Narayanam, J. M. R.; Krabbe, S.
W.; Stephenson, C. R. J. Chem. Commun. 2010, 46, 4985; (b)
Tucker, J. W.; Narayanam, J. M. R.; Krabbe, S. W.; Stephenson, C.
R. J. Org. Lett. 2010, 12, 368; (c) Furst, L.; Matsuura, B. S.;
Narayanam, J. M. R.; Tucker, J. W.;Stephenson, C. R. J. Org. Lett.
2010, 12, 3104; (d) Condie, A. G. ; Gonzelez-Gomez, J. C. ;
Stephenson, C. R. J. J. Am. Chem. Soc. 2010, 132, 1464; (e) Furst,
L.; Narayanam, J. M. R.; Stephenson, C. R. J. Angew. Chem. Int.
Ed. 2011, 50, 9655; (f) Tucker, J. W.; Narayanam, J. M. R.; Shah,
P. S.; Stephenson, C. R. J. Chem. Commun. 2011, 47, 5040; (g)
Nguyen, J. D.; Tucker, J. W.; Konieczynska, M. D.; Stephenson, C.
R. J. J. Am. Chem. Soc. 2011, 133, 4160; (h) Dai, C.; Narayanam, J.
M. R.; Stephenson, C. R. J. Nat. Chem. 2011, 3, 140.
(a) Jiang, H.; Huang, C.; Guo, J.; Zeng, C.; Zhang, Y.; Yu, S.
Chem. Eur. J. 2012, 18, 15158; (b) Pirtsch, M.Paris, S.; Matsuno,
T.; Isobe, H.; Reiser, O. Chem. Eur. J. 2012, 18, 7336; (c) Lin, R.;
Sun, H.; Yang, C.; Shenand, W.; Xia, W. Chem. Commun. 2014,
51, 399; (d) Deng, Q-H.; Chen, J-R.; Wei, Q.; Zhao, Q-Q.; Lu, L-
Q.; Xiao, W-J. Chem. Commun. 2015, 51, 3537; (e) Silvi, M.;
Arceo, E.; Jurberg, I. D.; Cassani, C.; Melchiorre, P. J. Am. Chem.
Soc. 2015, 137, 6120; (f) Zhang, Y.; An, Y.; Sun, J.; Ding, A.;
Wang, Y.; Rios, R.; Lin, H. G. Tetrahedron Lett. 2015, 56, 6499;
(g) Xu, X.-H.; Zhang, K.; Qing, F.-L. Angew. Chem., Int. Ed. 2016,
55, 1479; (h) Yuan, Z.-G.; Wang, Q.; Zheng, A.; Zhang, K.; Lu, L.-
Q.; Tang, Z.; Xiao. W.–J. Chem. Commun. 2016, 52, 5128; (i)
Ding, R.; Huang, Z.–D.; Liu, Z.–L.; Wang, T.–X.; Xu, Y.–H.; Loh,
T. P. Chem. Commun. 2016, 52, 5617.
10. For selected examples of our work on internal redox reaction and
cyclization sequences, see: (a) Kang, Y. K.; Kim, S. M.; Kim, D. Y.
J. Am. Chem. Soc. 2010, 132, 11847; (b) Kwon, Y. K.; Kang, Y.
K.; Kim, D. Y. Bull. Korean Chem. Soc. 2011, 32, 1773; (c) Kim,
D. Y. Bull. Korean Chem. Soc. 2013, 34, 3463; (d) Kim, M. H.;
Kim, D. Y. Bull. Korean Chem. Soc. 2013, 34, 3891; (e) Kang, Y.
K.; Kim, D. Y. Adv. Synth. Catal. 2013, 355, 3131; (f) Suh, C. W.;
Kim, D. Y. Bull. Korean Chem. Soc. 2014, 35, 98; (g) Kang, Y. K.;
Kim, D. Y. Chem. Commun. 2014, 50, 222; (h) Suh, C. W.; Woo,
S. B.; Kim, D. Y. Asian J. Org. Chem. 2014, 3, 399; (i) Suh, C. W.;
Kim, D. Y. Org. Lett. 2014, 16, 5374; (j) Suh, C. W.; Jeong, H. J.;
Kim, D. Y. Bull. Korean Chem. Soc. 2015, 36, 406; (k) Kim, M.
H.; Jeong, H. J.; Kim, D. Y. Bull. Korean Chem. Soc. 2015, 36,
1155; (l) Kwon, S. J.; Kim, D. Y. Chem. Rec. 2016, 16, 1191.
11. (a) Woo, S. B.; Kim, D. Y. J. Fluorine Chem. 2015, 178, 214; (b)
Suh, C. W.; Kim, D. Y. Tetrahedron Lett. 2015, 56, 5661.
12. General procedure for the visible-light-induced photocatalytic
alkylation/1,2-carbon migration sequences for the synthesis of
bis(alkoxycarbonyl)methyl-substituted cyclic ketones:
6.
An oven-dried Schlenk tube was equipped with a magnetic stir bar,
trimethyl(1-(1-arylvinyl)cyclobutoxy)silane 1 (0.3 mmol), fac-
Ir(ppy)3 (0.009 mmol), BrCH(CO2Et)2 (2, 0.6 mmol), 2,6-lutidine
(0.6 mmol) and DMSO (5 mL). The mixture was degassed by the
freeze-pump-thaw procedure. The reaction mixture was allowed to
stir for 1 h under irradiation of blue LEDs (5 W). After the reaction
was finished, the mixture was added ammonium chloride and
extracted with ethyl acetate. The organic layers were dried over
Na2SO4, concentrated in vacuum and purified by chromatography
on silica gel (ethyl acetate:n-hexane = 1:20) to afford the
7.
8.
(a) Weaver, J. D.; Recio, A.; Grenning, A. J.; Tunge, J. A. Chem.
Rev. 2011, 111, 1846; (b) Sun, X-Y.; Yu, S. Y. Org. Lett. 2014, 16,
2938; (c) Belhomme, M.-C.; Poisson, T.; Pannecoucke, X. J. Org.
Chem. 2014, 79, 7205; (d) Levin, V. V.; Trifonov, A. L.; Zemtsov,
A. A.; Struchkova, M. I.; Arkhipov, D. E.; Dilman, A. D. Org. Lett.
2014, 16, 6259; (e) Liu, Y.; Han, S.-J.; Liu, W.-B.; Stoltz, B. M.
Acc. Chem. Res. 2015, 48, 740.
alkylation-substituted cyclic ketones 3. Diethyl 2-((2-oxo-1-
phenylcyclopentyl)methyl)malonate (3a): 1H NMR (400 MHz,
CDCl3) 7.39-7.31 (m, 4 H), 7.25-7.23 (m, 1 H), 4.17-4.04 (m,
2H), 3.98 (q, J = 7.2 Hz, 2 H), 3.17 (dd, J = 7.2 Hz, 6.0 Hz, 1 H),
2.68 (dd, J = 14.6 Hz, 6.0 Hz, 1H), 2.62-2.58 (m, 1H), 2.31-2.26
(m, 3H), 2.01-1.91 (m, 2H), 1.83-1.71 (m, 1H), 1.23 (t, J = 7.0 Hz,
3H), 1.16 (t, J = 7.0 Hz, 3H) ; 13C NMR (100 MHz, CDCl3)
, 169.7, 169.1, 137.3, 128.7, 127.3, 127.2, 61.5, 61.4, 55.7,
48.6, 36.9, 36.
(a) Liu, X.; Xiong, F.; Huang, X.; Xu, L.; Li, P.; Wu, X. Angew.
Chem. Int. Ed. 2013, 52, 6962; (b) Chen, Z. M.; Bai, W.; Wang, S.
H.; Yang, B. M.; Tu, Y.Q.; Zhang, F. M. Angew. Chem. Int. Ed.
2013, 52, 9781; (c) Egami, H.; Shimizu, R.; Usui, Y.; Sodeoka, M.
Chem. Commun. 2013, 49, 7346; (d) Chen, Z-M.; Bai, W.; Wang,
S-H.; Yang, B-M.; Zhang, F-M.; Tu, Y-Q. Angew. Chem. Int. Ed.
2013, 52, 9781; (e) Ji, S-J.; Xu, X-P.; Zi, Y.; Meng, H.; Chu, X-Q.;
Chem. Eur. J. 2014, 20, 17198; (f) Chen, Z-M.; Zhang, Z.; Tu, Y-
Q.; Xu, M-H.; Zhang, F-M.; Li, C-C.; Wang, S-H. Chem. Commun.
2014, 50, 10805; (g) Ma, G.; Wan, W.; Li, J.; Hu, Q.; Jiang, H.;
Zhu, S.; Wang, J.; Hao, J. Chem. Commun. 2014, 50, 9749; (h) Shu,
X.–Z.; Zhang, M.; He, Y.; Frei, H.; Toste, F. D. J. Am. Chem. Soc.
2014, 136, 5844; (i) Li, Y.; Liu, B.; Ouyang, X.–H.; Song, R.–J.;
Li, J.–H.; Org. Chem. Front. 2015, 2, 1457; (j) Bunescu, A.; Wang,
Q.; Zhu, J. Angew. Chem. Int. Ed. 2015, 54, 3132; (k) Li, Y.; Liu,
B.; Li, H-B.; Wang, Q.; Li, J-H. Chem. Commun. 2015, 51, 1024;
(l) Song, R. J.; Tu, Y.–Q.; Zhu, D.–Y.; Zhang, F.–M.; Wang, S.–H.
Chem. Commun. 2015, 51, 749; (m) Huang, H. –L.; Yan, H.; Yang,
C.; Xia, W. Chem. Commun. 2015, 51, 4910; (n) Huang, H-L.; Yan,
H.; Gao, G-L.; Yang, C.; Xia, W. Asian J. Org. Chem. 2015, 4,
8, 34.4, 18.5, 14.0, 13.9; R (film) 1727 cm-1;
Supplementary Material
Supplementary data associated with this article can be found,
in the online version, at http://dx.doi.org
Click here to remove instruction text...

5
Highlight
1. We have developed the photocatalyzed alkylati
on/ring expansion of 1-(1-arylvinyl)cyclobutano
l derivatives.
2. Moderate to high yields (3a-3i, 56-77%) observ
ed.
3. This reaction requires short reaction time and ha
s broad substrate scope.