Expedient Synthesis of 1,5-Diketones by Rhodium-Catalyzed Hydroacylation Enabled by C-C Bond Cleavage

Article abstract of DOI:10.1021/jacs.7b05427

A rhodium-catalyzed intermolecular hydroacylation reaction of vinyl cyclobutanols with non-chelating aldehydes has been developed. This reaction offers a new and atom-economical approach for the selective preparation of 1,5-diketones in high yields. Experimental data suggest a sequential ring-opening, transfer hydrogenation, and hydroacylation mechanism. We propose that aldehyde decarbonylation is avoided by the formation of a novel rhodium enolate species that also accounts for the compatibility of a broad range of aldehydes and its anti-Markovnikov selectivity.

Full text of DOI:10.1021/jacs.7b05427

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Communication
Expedient Synthesis of 1, 5-Diketones by Rhodium-
Catalyzed Hydroacylation Enabled by C-C Bond Cleavage
Rui Guo, and Guozhu Zhang
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/jacs.7b05427 • Publication Date (Web): 31 Aug 2017
Downloaded from http://pubs.acs.org on August 31, 2017
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Expedient Synthesis of 1, 5-Diketones by Rhodium-Catalyzed Hy-
droacylation Enabled by C-C Bond Cleavage
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Rui Guo, Guozhu Zhang*
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Acadeꢀ
my of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China
Supporting Information Placeholder
mote binding of the alkene to rhodium; the following hy-
ABSTRACT: A rhodium-catalyzed intermolecular hydroac-
droacylation could occur across the extended carbon chain
after β-carbon elimination leading to 1, 5-diketones. Herein,
we report the successful implementation of this hypothesis
(Eq 4). Other well-established 1,5-diketone syntheses such as
Michael addition of ketones or derivatives with α, β-
unsaturated ketones,15a,15b dimerization of the condensation
products between aryl methyl ketones and aldehydes,15c and
ozonolysis of tetrasubstituted cyclopentenes sometimes suf-
fer from limited substrate scope. On the other hand, our
method has easy availability of starting materials, broad sub-
strate scope, atom economy and excellent regioselectivity.
ylation reaction of vinyl cyclobutanols with non-chelating
aldehydes has been developed. This reaction offers a new and
atom-economical approach for the selective preparation of 1,
5-diketones in high yields. Experimental data suggest a se-
quential ring opening, transfer hydrogenation, and hydroac-
ylation mechanism. We propose that aldehyde decarbonyla-
tion is avoided by the formation of a novel rhodium enolate
species that also accounts for the compatibility of a broad
range of aldehydes and its anti-Markovnikov selectivity.
Transition-metal-catalyzed hydroacylation of alkenes with
aldehydes is a straightforward and atom-economical method
for the synthesis of ketones.1 In 1972, Sakai et al. reported the
first example of rhodium-mediated intramolecular alkene
hydroacylation to form a cyclopentanone. 2 Since then, signif-
icant progress has been made on rhodium-catalyzed intra-
molecular hydroacylation of alkenes.3 Extending hydroacyla-
tion to intermolecular systems has proven to be challenging
because the acyl-rhodium intermediates undergo undesired
decarbonylation. To solve this problem, many elegant chela-
tion strategies to stabilize the key intermediate have been
extensively investigated. Both chelating aldehydes such as
salicylaldehydes,4 2-aminobenzaldehydes,5 sulfur-substituted
aldehydes,6 or (2-pyridyl)aldimines (Eqs 1, 2),7 as well as che-
lating alkene counterparts (Eq 3),4a,4b, 4e, 4d, 8 have been devel-
oped to facilitate C-H bond activation and suppress competi-
tive decarbonylation. This issue has also been addressed by
using cobalt,9 ruthenium,10 or nickel catalysts.11 Despite this
progress, chelation for selective hydroacylation with simple
aldehydes remains challenging.
The selective cleavage and functionalization of car-
bon−carbon single bonds by transition-metal catalysts has
become a useful synthetic method.12 Of those, cyclobutanols
are frequently employed as privileged building blocks for the
construction of diverse molecular scaffolds through metal-
mediated β-carbon elimination.13
Inspired by Dong’s work on alcohol-chelation-assisted hy-
droacylations with various aldehydes,4a, 14 we hypothesized
that a hydroxyl group in the vinyl cyclobutanol might pro-
In the initial test of our hypothesis, benzaldehyde was react-
ed with 1-vinyl cyclobutanol in toluene at 110 °C in the pres-
ence of a 2.5 mol % of [Rh(COD)Cl]2 (COD = 1,5-
cyclooctadiene) and 10 mol % of a triphenylphosphine lig-
and. The desired 1,5-diketone 2a was indeed isolated in 73%
yield (Table 1, entry 1). Various types of phosphine ligands
were then evaluated; PPh3 was the best ligand (Table 1, en-
tries 2-7). The reaction is very sensitive to the steric proper-
ties of the ligand.16 Bidentate ligands that are more sterically
congested (e.g., dppm, dppe, and dppp) lead to low yields of
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product, while ligands with a larger bite angle such as dppb
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4
5
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8
9
and dppf gave improved yields. K2CO3 could facilitate the
ring opening of cyclobutanol (Table 1, entry 8).13a, 17 Further
condition optimization showed that higher temperatures
(140 °C) in xylene were beneficial; quantitative yield (98%)
was achieved (Table 1, entry 10). Several other Rh catalysts
were surveyed with no positive effects for this chemistry (Ta-
ble 1, entries 11 and 12).
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Table 1. Evaluation of Reaction Parameters.
entrya catalyst
ligand base solvent temp (°C) time (h) yield (%)b
1
[Rh(COD)Cl]2
[Rh(COD)Cl]2
[Rh(COD)Cl]2
[Rh(COD)Cl]2
[Rh(COD)Cl]2
[Rh(COD)Cl]2
[Rh(COD)Cl]2
[Rh(COD)Cl]2
[Rh(COD)Cl]2
[Rh(COD)Cl]2
[Rh(COD)OH]2
Rh(PPh3)2Cl
PPh3
PCy3
dppm
dppe
dppp
dppb
dppf
PPh3
PPh3
PPh3
PPh3
—
K3PO4
K3PO4
K3PO4
K3PO4
K3PO4
K3PO4
K3PO4
K2CO3
K3PO4
K2CO3
K2CO3
K2CO3
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
xylene
xylene
xylene
xylene
110
110
110
110
110
110
110
110
140
140
140
140
12
12
12
12
12
12
12
12
6
73
36
10
14
10
55
63
83
96
98
56
39
2
3
4
aThe reaction conditions were aldehyde (0.2 mmol), 1a (0.3 mmol), [Rh(COD)Cl]2
(2.5 mol %), PPh3 (10 mol %), K2CO3 (5 mol %), xylene (0.2 M) at 140 °C for 6 h
unless noted otherwise. bIsolated yield. c3.0 equiv. of 1a was used.
5
6
Table 3. Substrate Scope with Respect to Cyclobutanolsa,b
.
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8
9
10
11
12
6
6
6
aThe reaction conditions were benzaldehyde (0.2 mmol), 1a (0.3 mmol), [Rh] cataꢀ
lyst (2.5 mol %), ligand (10 mol %), base (5 mol %), solvent (0.2 M) unless noted
otherwise. bIsolated yield.
Using optimal reaction conditions, we evaluated the coupling
of vinyl cyclobutanol 1a and aldehydes with diverse steric
and electronic properties (Table 2). A variety of electron rich
or electron poor phenyl rings were tolerated on the alde-
hydes furnishing the corresponding 1, 5-diketones in good to
excellent yields (Table 2, 2b-2m). Terephthalaldehyde un-
derwent double hydroacylation smoothly in the presence of
3.0 equiv. of 1a (2n). Beside phenyl, other aromatic groups
including naphthalene, furan, thiophene, pyrrole, and indole
also demonstrated excellent compatibility with current reac-
tion conditions (2o-2t). Traditionally challenging alkenyl
aldehydes that are prone to interfere with the hydroacylation
or deactivate the rhodium catalyst by complexation also
proved to be good substrates (2u-2y). Primary and secondary
aliphatic aldehydes were successfully transformed into
diketones in excellent results (2z-2ad).
We then turned our attention to the variation on the vinyl
part (Table 3). Vinyl cyclobutanol with different substitutions
on the carbon-carbon double bond underwent expected hy-
droacylation to give the corresponding 1, 5-diketones in fair
to good yields (2ae-2ah). Allyl cyclobutanol was a suitable
substrate for this reaction—albeit with a slightly decreased
yield (2ai).
a
The reaction conditions were benzaldehyde (0.2 mmol),
1 (0.3 mmol),
[Rh(COD)Cl]2 (2.5 mol %), PPh3 (10 mol %), K2CO3 (5 mol %), and xylene (0.2 M)
at 140°C for 6 h. bIsolated yield.
To our surprise, internal substitution of the olefin bond (1g,
1h) reversed the site selectivity (2aj, 2ak) and an inferior
yield was attained with bulkier phenyl substitution. Interest-
ingly, the reaction of 4-butenyl cyclobutanol 1i yielded 2al in
46% yield indicating a distinct hydroacylation following the
Markovnikov rule.18 Monosubstitutions of cyclobutanol could
be allowed at the 2 or 3 position giving 2am~2ao in low to
moderate yields. For 1l, ring opening occurred on the non-
substituted side.
Table 2. Substrate Scope with Respect to Aldehydesa, b
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membered metal complex G is more favorable leading to
anti-Markovnikov products via H. 4a, 4b, 4e, 4d, 14
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8
Compound 2a could be made at the gram scale (Scheme 2)
and could be used to prepare various cyclic molecules. For
example, treatment of 2a with Et3SiH and TMSOTf resulted
in the 2,6-disubstituted tetrahydropyran 3. The 2a could then
undergo double reductive amination to afford perperidine 4.
Furthermore, 1,2-cyclopentanediol 5 could be readily ac-
cessed in the presence of TiCl4 and Zn in one step. Under
basic conditions, an intramolecular Claisen condensation
provided 6 in quantitative yield. Norlobelane could be ac-
cessed through 7. Moreover, an aldehyde derived from natu-
rally occurring lithocholic acid reacted smoothly to give 8.
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To investigate the reaction mechanism, we probed the reac-
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tion by tracking the deuterium label for hydroacylation with
deuterated benzaldehyde. NMR analysis revealed that deu-
terium was only incorporated into the methylene carbon at
the β-position of the resulting diketone d-2a (Eq 5). To fur-
ther probe the mechanism, we synthesized a dienone and
deuterated benzylic alcohol. A deuterated rhodium hydride
and benzaldehyde should form by dehydration that was ena-
bled by a rhodium catalyst. Indeed, about 14% of the desired
diketone d2-2a was isolated under standard conditions.19
NMR analysis of the product revealed that over 80% deuteri-
um was incorporated into the same methylene carbon and
about 50% of deuterium incorporation was at the terminal
methyl group (Eq 6). These two experiments suggest the
involvement of hydrometallation and hydroacylation. In an-
other control experiment, 1d reacted under standard condi-
tions without an aldehyde to form a linear enone with a
swapped double bond indicating an intramolecular transfer
hydrogenation pathway (Eq 7).20 The kinetic isotope effect
(KIE) and Hammett studies further suggest that the oxidative
addition of the rhodium to the aldehyde is the rate-limiting
step.21
Scheme 2. Synthetic Utilities of 1, 5ꢀDiketone and Application
of the Method.
In summary, we developed a highly selective rhodium-
catalyzed hydroacylation reaction of alkenyl cyclobutanols
with non-chelating aldehydes. This reaction offers a new
approach for the selective preparation of 1, 5-diketones in an
atom-economical fashion. The experimental and deuterium-
labeling studies show that the reaction proceeds through a
sequential ring-opening, transfer hydrogenation, and hy-
droacylation process. These results also highlight the special
role of rhodium enolate species for the broad substrate scope
and excellent regioselectivity of this chemistry. Our future
work will focus on developing new intermolecular hydroac-
ylation reactions and realizing appropriate asymmetric con-
trol.
Scheme 1. Proposed Reaction Mechanism
Previous studies22, 23 and our own observations suggest the
mechanism proposed in Scheme 1. First, there is a rhodium-
mediated ring opening through β-carbon cleavage followed
by β-hydride elimination via intermediates A, B that leads to
dienone C. Next, ketone-assisted selective hydrometallation
occurs on the electron-deficient and vicinal double bond (D)
followed by migration leading to the Rh enolate species E.
Hydroacylation then occurs on the distal double bond to
afford the final 1, 5-diketone. Of note, the acyl rhodium (III)
hydride F is coordinatively saturated and stable toward de-
carbonylation. Furthermore, the formation of the 6-
ASSOCIATED CONTENT
Supporting Information
This material is available free of charge via the Internet at
http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*guozhuzhang@sioc.ac.cn
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(9) (a) Chen, Q.ꢀA.; Kim, D. K.; Dong, V. M. J. Am. Chem. Soc. 2014,
136, 3772. (b) Lenges, C. P.; White, P. S.; Brookhart, M. J. Am.
Chem. Soc. 1998, 120, 6965.
Notes
The authors declare no competing financial interests.
(10) (a) Kim, J.; Yi, C. S. ACS Catal. 2016, 6, 3336. (b) Li, B.; Park, Y.;
Chang, S. J. Am. Chem. Soc. 2014, 136, 1125. (c) Omura, S.; Fukuꢀ
yama, T.; Horiguchi, J.; Murakami, Y.; Ryu, I. J. Am. Chem. Soc.
2008, 130, 14094. (d) Shibahara, F.; Bower, J. F.; Krische, M. J. J.
Am. Chem. Soc. 2008, 130, 14120. (e) Hong, Y.ꢀT.; Barchuk, A.;
Krische, M. J. Angew. Chem., Int. Ed. 2006, 45, 6885. (f) Kondo, T.;
Hiraishi, N.; Morisaki, Y.; Wada, K.; Watanabe, Y.; Mitsudo, T. Or-
ganometallics 1998, 17, 2131. (g) Kondo, T.; Akazome, M.; Tsuji,
Y.; Watanabe, Y. J. Org. Chem. 1990, 55, 1286. (h) Kondo, T.; Tanꢀ
tayanon, S.; Tsuji, Y.; Watanabe, Y. Tetrahedron Lett. 1989, 30,
4137.
ACKNOWLEDGMENTS
We are grateful to NSFCꢀ21421091, XDB20000000, the “Thouꢀ
sand Plan” Youth Program, the State Key Laboratory of Organoꢀ
metallic Chemistry, the Shanghai Institute of Organic Chemistry,
and the Chinese Academy of Sciences. We thank professor Guoꢀ
sheng Liu (SIOC) for helpful suggestions on this project and Dr.
Xiaoyong Li (DOW Chemical) for proofreading the manuscript.
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53
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(11) Xiao, L.ꢀJ.; Fu, X.ꢀN.; Zhou, M.ꢀJ.; Xie, J.ꢀH.; Wang, L.ꢀX.; Xu, X.ꢀ
F.; Zhou, Q.ꢀL. J. Am. Chem. Soc. 2016, 138, 2957.
REFERENCES
(1) For reviews, see: (a) Park, J. W.; Kou, K. G. M.; Kim, D. K.; Dong,
V. M. Chem. Sci. 2015, 6, 4479. (b) Willis, M. C. Chem. Rev. 2010,
110, 725. (c) Park, Y. J.; Park, J.ꢀW.; Jun, C.ꢀH. Acc. Chem. Res.
2008, 41, 222. (d) Fu, G. C. In Modern Rhodium Catalyzed Organic
Reactions; Evans, P. A., Ed.; WileyꢀVCH: New York, 2005; pp 79ꢀ
91, and references therein.
(12) For reviews, see: (a) Souillart, L.; Cramer, N. Chem. Rev. 2015, 115,
9410. (b) Marek, I.; Masarwa, A.; Delaye, P.ꢀO.; Leibeling, M. An-
gew. Chem., Int. Ed. 2015, 54, 414. (c) Chen, F.; Wang, T.; Jiao, N.
Chem. Rev. 2014, 114, 8613. (d) Dermenci, A.; Coe, J. W.; Dong, G.
Org. Chem. Front. 2014, 1, 567. (e) FloresꢀGaspar, A.; Martin, R.
Synthesis 2013, 45, 563. (f) Park, Y. J.; Park, J.ꢀW.; Jun, C.ꢀH. Acc.
Chem. Res. 2008, 41, 222. (g) Murakami, M.; Ito, Y. Top. Organ-
omet. Chem. 1999, 3, 97. (h) Dong, G. Topics in Current Chemistry
346, SpringerꢀVerlag Berlin Heidelberg, 2014.
(13) For reviews, see: (a) Guo, R.; Zheng, X.; Zhang, D.; Zhang, G.
Chem. Sci. 2017, 8, 3002. (b) Zhao, H.; Fan, X.; Yu, J.; Zhu, C. J.
Am. Chem. Soc. 2015, 137, 3490. (c) Ishida, N.; Shimamoto, Y.;
Yano, T.; Murakami, M. J. Am. Chem. Soc. 2013, 135, 19103. (d)
Ishida, N.; Sawano, S.; Masuda, Y.; Murakami, M. J. Am. Chem. Soc.
2012, 134, 17502. (e) Seiser, T.; Cramer, N. J. Am. Chem. Soc. 2010,
132, 5340. (f) ÁlvarezꢀBercedo, P.; FloresꢀGaspar, A.; Correa, A.;
Martin, R. J. Am. Chem. Soc. 2010, 132, 466. (g) Matsumura, S.;
Maeda, Y.; Nishimura, T.; Uemura, S. J. Am. Chem. Soc. 2003, 125,
8862.
(14) Murphy, S. K.; Bruch, A.; Dong, V. M. Chem. Sci. 2015, 6, 174.
(15) For selected examples, see: (a) Marx, A.; Yamamoto, H. Angew.
Chem., Int. Ed. 2000 ，39 ，178. (b) Onishi, Y.; Yoneda, Y.;
Nishimoto, Y.; Yasuda, M.; Baba, A. Org. Lett. 2012, 14, 5788. (c)
Takahashi, H.; Arai, T.; Yanagisawa, A. Synlett 2006, 17, 2833.
(16) See the Supporting Information for the detailed ligands screening.
(17) Souillart, L.; Cramer, N. Chem. Sci. 2014, 5, 837.
(18) See the Supporting Information for rational analysis for the reversed
selectivity observed.
(19) Low yield of product is probably due to the slow dehydration of
aldehyde and quick isomerization of dienone.
(2) Sakai, K.; Ide, J.; Oda, O.; Nakamura, N. Tetrahedron Lett. 1972,
13, 1287.
(3) (a) Crépin, D.; Dawick, J.; Aïssa, C. Angew. Chem., Int. Ed. 2010,
49, 620. (b) Aïssa, C.; Fürstner, A. J. Am. Chem. Soc. 2007, 129,
14836. (c) Aloise, A. D.; Layton, M. E.; Shair, M. D. J. Am. Chem.
Soc. 2000, 122, 12610. (d) Sato, Y.; Oonishi, Y.; Mori, M. Angew.
Chem. Int. Ed. 2002, 41, 1218. (e) Barnhart, R. W.; Wang, X.;
Noheda, P.; Bergens, S. H.; Whelan, J.; Bosnich, B. J. Am. Chem.
Soc. 1994, 116, 1821. (f) Wu, X.ꢀM.; Funakoshi, K.; Sakai, K. Tet-
rahedron Lett. 1992, 33, 6331. (g) James, B. R.; Young, C. G. J.
Chem. Soc. Chem. Commun. 1983, 1215. (h) Lochow, C. F.; Miller,
R. G. J. Am. Chem. Soc. 1976, 98, 1281. (i) Milstein, D. Organome-
tallics 1982, 1, 1549.
(4) (a) Murphy, S. K.; Bruch, A.; Dong, V. M. Angew. Chem., Int. Ed.
2014, 53, 2455. (b) Murphy, S. K.; Coulter, M. M.; Dong, V. M.
Chem. Sci. 2012, 3, 355. (c) Delius, M.; Le, C. M.; Dong, V. M. J.
Am. Chem. Soc. 2012, 134, 15022. (d) Murphy, S. K.; Petrone, D. A.;
Coulter, M. M.; Dong, V. M. Org. Lett. 2011, 13, 6216. (e) Coulter,
M. M.; Kou, K. G. M.; Galligan, B.; Dong, V. M. J. Am. Chem.
Soc. 2010, 132, 16330. (f) Coulter, M. M.; Dornan, P. K.; Dong, V.
M. J. Am. Chem. Soc. 2009, 131, 6932. (g) Stemmler, R. T.; Bolm, C.
Adv. Synth. Catal. 2007, 349, 1185. (h) Tanaka, K.; Tanaka, M.;
Suemune, H. Tetrahedron Lett. 2005, 46, 6053. (i) Kokubo, K.; Matꢀ
sumasa, K.; Nishinaka, Y.; Miura, M.; Nomura, M. Bull. Chem. Soc.
Jpn. 1999, 72, 303.
(5) Bendorf, H. D.; Ruhl, K. E.; Shurer, A. J.; Shaffer, J. B.; Duffin, T.
O.; LaBarte, T. L.; Maddock, M. L.; Wheeler, O. W. Tetrahedron
Lett. 2012, 53, 1275.
(6) (a) Prades, A.; Fernández, M.; Pike, S. D.; Willis, M. C.; Weller, A.
S. Angew. Chem., Int. Ed. 2015, 54, 8520. (b) Chaplin, A. B.; Hoopꢀ
er, J. F.; Weller, A. S.; Willis, M. C. J. Am. Chem.
Soc. 2012, 134, 4885. (c) Moxham, G. L.; RandellꢀSly, H. E.; Brayꢀ
shaw, S. K.; Woodward, R. L.; Weller, A. S.; Willis, M. C. Angew.
Chem., Int. Ed. 2006, 45, 7618. (d) Willis, M. C.; McNally, S. J.;
Beswick, P. J. Angew. Chem., Int. Ed. 2004, 43, 340.
(20) For example of Rhꢀcatalyzed isomerization of β, γꢀunsaturated
ketone to conjugated enone, see: Zhuo, L.ꢀG.; Yao, Z.ꢀK.; Yu, Z.ꢀX.
Org. Lett. 2013, 15, 4634.
(21) See the Supporting Information for the detailed experimental inforꢀ
mation.
(22) Matsuda, T.; Makino, M.; Murakami, M. Org. Lett. 2004, 6, 1257.
(23) For transitionꢀmetal hydride elimination followed by readdition with
opposite regiochemistry, see: (a) Yoshida, K.; Hayashi, T. J. Am.
Chem. Soc. 2003, 125, 2872. (b) Gagnier, S. V.; Larock, R. C. J. Am.
Chem. Soc. 2003, 125, 4804. (c) Suginome, M.; Matsuda, T.; Ito, Y.
J. Am. Chem. Soc. 2000, 122, 11015. (d) Ittel, S. D.; Johnson, L. K.
Chem. Rev. 2000, 100, 1169.
(7) (a) Vautravers, N. R.; Regent, D. D.; Breit, B. Chem. Com-
mun. 2011, 47, 6635. (b) Jo, E.ꢀA.; Jun, C.ꢀH. Tetrahedron
Lett. 2009, 50, 3338. (c) Jo, E.ꢀA.; Jun, C.ꢀH. Eur. J. Org.
Chem. 2006, 2504. (d) Jun, C.ꢀH.; Lee, D.ꢀY.; Lee, H.; Hong, J.ꢀ
B. Angew. Chem., Int. Ed. 2000, 39, 3070.
(8) Shibata, Y.; Tanaka, K. J. Am. Chem. Soc. 2009, 131, 12552. (b)
Tanaka, K.; Shibata, Y.; Suda, T.; Hagiwara, Y.; Hirano, M. Org.
Lett. 2007, 9, 1215.
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