A palladium-catalyzed multi-component annulation approach towards the synthesis of phenanthrenes

Article abstract of DOI:10.1039/c9ob00228f

An efficient palladium-catalyzed three-component cascade reaction has been developed for the facile construction of phenanthrene frameworks. The transformation is driven by a controlled reaction sequence of Suzuki-Miyaura coupling followed by the insertion of alkynes, and finally, annulation to yield phenanthrene derivatives via C-H activation. This methodology is able to accommodate a variety of substrates and affords the anticipated products in good to excellent yields.

Full text of DOI:10.1039/c9ob00228f

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Takeharu Haino et al.
Solvent-induced emission of organogels based on tris(phenylisoxazolyl)
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DOI: 10.1039/C9OB00228F
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A Palladium-Catalyzed Multi-component Annulation Approach
towards Synthesis of Phenanthrenes
Juan Song*, Songjiang Wang, Haisen Sun, Yuxuan Fan, Kang Xiao and Yan Qian
Received 00th January 20xx,
Accepted 00th January 20xx
DOI: 10.1039/x0xx00000x
An efficient palladium-catalyzed three-component cascade alkynylbiphenyls (approach A, 1)6-13, 2-formyl-2’-substituted
reaction has been developed for the facile construction of biphenyls (approach A, 2)14-18 or 2,2’-divinylbiphenyls
phenanthrene frameworks. The transformation is driven by a (approach A, 3)2. These pioneering works have great values for
controlled reaction sequence of Suzuki-Miyaura coupling followed the later researches, but most of their starting substrates were
by the insertion of alkynes, and finally, annulation to yield not readily available in the commercial sources. Second, in
phenanthrene derivatives via C-H activation. This methodology is approach B (Scheme 1), there provided three options for the
able to accommodate a variety of substrates and affords the potential disconnection of two bonds in inner ring4, 5, 19-36
,
anticipated products in good to excellent yields.
which indicated more flexible strategies and more expanded
substrate scope. Among them, the annulation of 2-
functionalized biaryl and an alkyne via C-H bond activations
has attracted more attention (Scheme 1, approach B, 1a).
Various biaryls have been served as the substrates applied in
the palladium4, 19-23, rhodium24, iron5, iridium25, and
chromium26 catalysis. However, formation of three new C-C
bonds in one pot (Scheme 1, approach C)37-45 would be more
attractive because of the overwhelming advantages, including
the commercially available or easily accessible substrates, step
economy, increasing of molecular complexity with minimized
isolation, and so on. Thus, it is highly desired that
phenanthrene is synthesized via a multicomponent coupling.
As shown in approach C (Scheme 1), arynes are very reactive
intermediates and have been frequently used to co-trimerize
with internal alkynes under palladium catalysis to afford
Phenanthrenes are one of the most simple and stable fused
aromatics among polycyclic aromatic hydrocarbons (PAHs).
They have attracted much attention because of their
extraordinary physical properties, bioactivities1 and electronic
properties2, 3. Especially, with the development of organic
semi-conductive materials during the last four decades,
phenanthrene is qualified as a highly attractive building block
for conjugated systems owing to its high resonance energy and
high energy gap. A tremendous scientific effort has been
devoted to their potential applications in the field of organic
electronics such as organic field-effect transistors (OFETs)4,
OLED emitter material,5 and so on. Based on these promising
properties, synthetic chemists have figured out various
preparative methods of synthesizing phenanthrenes during
the past century (Scheme 1)2, 4-45 and almost all researches
have focused on the construction of inner ring of
phenanthrene. As described in Scheme 1, those synthetic
strategies could be divided into three categories depending
upon the number of new bonds formed in the reaction. First,
approach A (Scheme 1) showed that only one new C-C bond
was formed in the fuse ring construction, phenanthrenes were
synthesi zed vi a i ntramol ecul ar cycl i zati on of o-
phenanthrene derivatives (Scheme 1, approach C, 1)37-41
.
Another strategy is that the biaryl motif generated in situ in
the reaction and then, performs the annulation to give the
desired product with the internal alkynes42-45. For example,
Nishihara et al., reported a palladium-catalyzed three-
component reaction using aryl halides coupled with o-
bromobenzyl alcohols (Scheme 1, approach C, 2)4 2
.
Furthermore, palladium-catalyzed norbornene-mediated
arylation is a useful method to generate biaryl motif (Scheme
1, approach C, 3)43-45. Catellani, et al.,44 and Kwong, et al.,45
reported relevant works, respectively. Herein, we disclosed a
novel efficient three-component reaction catalyzed by
palladium to construct phenanthrene derivatives from o-
bromoaryl iodides, aryl boronic acid and alkynes (Scheme 1,
approach C, 4). The transformation is driven by a controlled
Key Laboratory for Organic Electronics and Information Displays & Jiangsu Key
Laboratory for Biosensors, Institute of Advanced Materials (IAM), Jiangsu
National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing
University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, P.
R. China.
* Corresponding author: iamjsong@njupt.edu.cn.
Electronic Supplementary Information (ESI) available: [details of any supplementary
information available should be included here]. See DOI: 10.1039/x0xx00000x
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reaction sequence of Suzuki-Miyaura coupling to form biaryl (Table 1, entry 9) or PdCl2 (Table 1, entry 10) reVsiuewltAerdticlienOntlhinee
DOI: 10.1039/C9OB00228F
m o t i f w h i c h f o l l o w e d b y a w e l l - d o c u m e n t e d identification of Pd(OAc)2 as the optimal palladium precursor.
Approach A: One new bond formed in the reaction2, 6-18
Solvent of the reaction was also screened (Table 1, entries 11-
13), unfortunately, no improved result was obtained.
R
CHO
Delightedly, the yield of 4a was remarkably improved to 84%
or
R1
R2
R
2
3
1
when decreasing the amount of Cs2CO3 from 3 equiv. to 2 equiv.
(Table 1, entry 14 vs 5). Furthermore, increasing the loading of
diphenylacetylene to 2.5 equiv. resulted in a higher yield up to
90% (Table 1, entry 15). However, the reaction was obvious
sluggish at lower temperature (Table 1, entry 16). The optimum
reaction conditions thus far being developed employing 1.0
2
R = COCH3, COOCH3, CONHCH3, CN, SO2Ph
1
R1
R2
3
Approach B: Two new bonds formed in the reaction4, 5, 19-36
X
Y
equiv. of o-bromoiodobenzene,
1
equiv. of 4-
R1
R2
+
methylphenylboronic acid with 2.5 equiv. of diphenylacetylene,
5 mol% of Pd(OAc)2, 10 mol% of DPEphos, 2.0 equiv. of Cs2CO3,
1.0 equiv. of PivOH in toluene (2 mL) at 120 C for 24 h. With
this optimal procedure, phenanthrene 4a was obtained in 92%
of isolated yield (Table 1, entry 15).
X = Br, I, COOH, COCl, B(OH)2, MgBr, H
Y = Br, I, H
R1
R2
1a
1b
H3C
CH3
o
M
R1
R2
+
or
1c
R1
R2
+
With the optimized reaction conditions successfully established,
various arylboronic acids were firstly subjected to the reactions with
o-bromoiodobenzene and diphenylacetylene. As listed in Table 2, the
newly developed method accommodated a variety of 4-substituted
arylboronic acids (4a-4l) and afforded the desired products in good
to excellent yield (71-93%). In general, arylboronic acids bearing
electron-donating substituents at 4 position (4a, 4b, 4c, 4d, 4e, 4f, 4l)
slightly worked better than those with electron-withdrawing
substituents (4g, 4h, 4i, 4j, 4k). These experimental results indicated
a weak electronic effect in this reaction for arylboronic acids.
However, steric hindrance has a great influence on this reaction,
Bpin Bpin
SiMe3
Br
Br
R1
R2
R1
Br
Bpin
Bpin
R2
2
3
or
or
HO
H3C
+
OTf
X
Y
X
CH3
R1
R2
B(OH)2
+
R1
CHO
X = Br, I
R1 = COCH3, COOCH3, CONHCH3, CN, SO2Ph
Approach C: Three new bonds formed in the reaction37-45
R1
R2
R1
R1
R2
R2
or
Br
COOEt
+
2
I
+
1
2
+
X
+
OH
Table 1. Screen of Reaction Conditions a
3
X = Br, I
H3C CH3
I
I
+
Br
R1
R2
or
+
2
COOH
B(OH)2
R3
R4
I
our design
R1
R2
R3
R4
+
+
4
R2
Br
R1
Scheme 1.Typical synthetic approaches to Phenanthrenes
process of the insertion of alkynes46-49, and finally, annulation
to give phenanthrene derivations via C-H activation.
The reaction conditions were optimized based on the model
transformation of o-bromoiodobenzene, diphenylacetylene
with 4-methylphenylboronic acid. Ligands screening were
initially carried out with Pd(OAc)2 as the catalyst precursor and
K2CO3 / PivOH as the base in toluene at 120 oC for 24 h. The
preliminary results were outlined in Table 1. Only trace of 2-
methyl-9,10-diphenylphenanthrene (4a) was observed for t-
Bu3P.HBF4 as the ligand (Table 1, entry 3). Dppm (Table 1, entry
1) and PPh3 (Table 1, entry 4) gave inferior result in the reaction.
The optimal ligand was DPEphos (Table 1, entry 2) and afforded
the desired product of 4a in 49% yield (determined by 1H NMR
analysis). Then, the influence of base was examined (Table 1,
entry 5-7). The yield was significantly increased to 70% with
Cs2CO3 as base (Table 1, entry 5). t-BuONa and K3PO4 were less
effective (Table 1, entries 6 and 7) for this reaction. Several
palladium sources were investigated for the transformation.
Switching Pd(OAc)2 to Pd(PPh3)4 (Table 1, entry 8 ), Pd(dba)2
2 | J. Name., 2012, 00, 1-3
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Ph
Ph
CH3
Ph
View Article Online
Pd(OAc)2
Br
DOI: 10.1039/C9OB00228F
R1
R2
+
Ph
DPEphos
Cs2CO3, PivOH
120 o
24h
+
CH3
Br
I
Ph
(HO)2B
R2
[Pd], ligand, base
I
+
R1
Ph
3a
+
slovent, 24h, 120 o
C
C
,
4
2
1
(HO)2B
Ph
Ph
3a
Ph
2a
Ph
Ph
1a
Ph
4a
yield (%)
Ph
Ph
Ph
CH3
Ph
entry
ligand
base
[Pd]
solvent
toluene
toluene
1
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(PPh3)4
Pd(dba)2
PdCl2
K2CO3
K2CO3
K2CO3
K2CO3
Cs2CO3
dppm
10
4d
88%
4a
4b
91%
4c
90%
CH3
t-Bu
92%
2
DPEphos
49
CH3
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
t-Bu3P.HBF4 toluene
3
trace
5
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
4
PPh3
toluene
toluene
toluene
toluene
toluene
toluene
toluene
THF
5
DPEphos
DPEphos
DPEphos
DPEphos
DPEphos
DPEphos
DPEphos
DPEphos
DPEphos
DPEphos
DPEphos
DPEphos
70
4e
93%
4f
83%
4h
80%
4g
81%
n-C4H9
Cl
OCH3
F
6
t-BuONa
K3PO4
33
Ph
Ph
7
35
8
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
Cs2CO3
61
4i
4j
71%
4k
82%
4l
87%
9
CF3
58
78%
NO2
Ph
F
CN
Ph
10
11
12
13
14b
15b,c
32
Ph
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
19
+
+
CH3
dioxane
DMF
59
4ma
4mb
4na
4nb
56%
31%
4ma 4mb
trace
84
CH3
Ph
F
4na 4nb
:
= 1.6 : 1
:
= 1 : 1.9
Ph
toluene
toluene
toluene
Ph
Ph
H C
3
H3C
Ph
Ph
Ph
PH
CH3
90/92e
60
16b,c,d Pd(OAc)2
H3C
F
CH3
4r
89%
4o
4p
4q
86%
Ph
a
1a
2a
3a
(0.3 mmol), (0.3 mmol), [Pd]
Reaction Conditions:
(0.3 mmol),
CH3
trace
trace
(0.015 mmol), ligand (0.03 mmol), base (0.9 mmol), PivOH (0.3 mmol) in
solvent (2 mL) at 120 o for 24 h. NMR Yield. b Cs2CO3 (0.6 mmol) was
loaded. c 3a (0.75 mmol) was loaded. d The reaction was carried out at
110o e Isolated yield.
Ph
Ph
Ph
C
H3C
CF3
H3C
H3C
Ph
H3C
Ph
Ph
Ph
Ph
Ph
C.
4s
90%
4t
4u
83%
4v
80%
almost no product obtained for o-substituted phenylboronic
acid (4o, 4p). A relatively low yield was obtained for meta-
substituted phenylboronic acids and gave a mixture of two
regio-isomers (4ma and 4mb, 4na and 4nb). The ratio of two
isomers was relied on the electronic effect and steric
hindrance. Successively, Substituted o-bromoiodobenzenes
were examined under the optimized conditions (4q-4x). 2-
Bromo-4-methyliodobenzene reacted smoothly with various
arylboronic acids under the standard conditions to afford the
corresponding products (4q, 4r, 4s, 4t, 4u, 4v) in good to
excellent yields (80-90%). Whereas, for 2-bromo-5-
fluoroiodobenzene, a mixture of two regio-isomers (4na and
4nb, 4wa and 4wb, 4xa and 4xb)
F
CN
t-Bu
86%
Ph
F
Ph
F
Ph
Ph
Ph
Ph
Ph
+
+
F
F
4na
4xa
4wa
4nb
4wb
80%
4wa 4wb
=1 : 2.1
89%
4na 4nb
F
F
:
= 1 : 1.1
F
:
Ph
Ph
+
Ph
F
4xb
t-Bu
t-Bu
84%
4xa 4xb
:
= 1 : 1.3
a
1
2
3a
Reaction Conditions: (0.3 mmol), (0.3 mmol), (0.75 mmol), Pd(OAc)2 (0.015 mmol),
DPEphos (0.03 mmol), Cs2CO3 (0.6 mmol), PivOH (0.3 mmol) in toluene (2 mL) at 120 o
C
for 24 h. isolated yield.
Ph
Ph
PdII
F
Ph
Ph
F
Table 2. Palladium-catalyzed three-component coupling of
diphenylacetylene with various o-bromoiodobenzenes and
arylboronic acids a
Br
Pd0
4na
I
Pd0
Br
F
F
F
F
+
+
B(OH)2
PdII
Ph
Ph
4nb
1,4-palladium migration
Scheme 2. The 1,4-palladium migration in the reaction
were obtained in high yields (80-89%). The generation of isomers of
4nb, 4wb and 4xb could be ascribed to the 1,4-palladium migration
(Scheme 2). The ratio of two isomers indicated that the main
products (4nb, 4wb, 4xb) were generated through 1,4-palladium
migration process for 2-bromo-5-fluoroiodobenzene.
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J. Name., 2013, 00, 1-3 | 3
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Having established the scope of o-bromoiodobenzenes and The substitution of OCH3 and CF3 at 2-position gave trace or no
View Article Online
DOI: 10.1039/C9OB00228F
arylboronic acids, various alkynes were explored successively (Table product at all. In the annulation of diarylacetylenes bearing CH3 (5k)
3). Under the identical reaction conditions, treatment of o-bromo- and CF3 (5l) substituents at 3-position, 9,10-diarylphenanthrenes 6k
iodobenzene (1a), phenylboronic acid (2b) with diarylacetylenes and 6l were formed in 78% and 62% yield, respectively, which were
bearing electron-donating or electron-withdrawing substituents at lower than those 4-substituted analogs (6i and 6c), and confusingly,
the para positions (5a-5i) provided the expected phenanthrenes (6a- no product found for di(3-methoxyphenyl)acetylene. We repeated
the experiments and observed the same results. Only 2-bromo-1,1'-
Table 3. Palladium-catalyzed three-component coupling of biphenyl and the substrate of di(3-methoxyphenyl)acetylene found
various diarylacetylenes with o-bromoiodobenzene and in crude NMR spectrum which indicated that, at second stage, the
phenylboronic acid a
insertion of alkynes was failed. Notably, the dialkylacetylene 2-
heptyne was applicable to the procedure, providing the annulation
product 6m in good yield (76%), and the alkylarylacetylene, 1-
phenylpropyne, was converted to the phenanthrene 6n in the lower
yield of 57%. Unfortunately, only 30% yield of product 6o obtained
in this reaction when using methyl but-2-ynoate as the substrate and,
trace or no product found for the annulation of methyl 3-
phenylpropiolate and dimethyl but-2-ynedioate.
R3
R3
R4
Pd(OAc)2
DPEphos
Br
+
+
Cs2CO3, PivOH
R4
5
(HO)2B
I
120 o
24h
C,
1a
2b
6
t-Bu
t-Bu
H3CO
OCH3
F3C
CF3
F
F
This transformation is driven by a controlled reaction sequence
of Suzuki-Miyaura coupling followed by the insertion of alkynes,
and finally, annulation to give phenanthrene derivatives via C-H
activation. The conclusive evidence for the suggested sequence was
provided by the annulation of 2-bromo-4’-methyl-1,1'-biphenyl
under the standard condition leading to the product of 4a in 92%
yield (Scheme 3).
6d
83%
6b
86%
6c
80%
6a
88%
H3C
t-Bu H3C
OCH3 H3C
CF3H3C
F
6g
81%
6h
85%
6f
87%
6e
88%
H3C
CH3
Conclusions
H3C
CH
3 F3C
CF
3 H3CO
OCH3
In summary, we have successfully developed a direct and
highly efficient approach for the construction of phenanthrenes
via a Pd-catalyzed cascade process. The reactions occurred
smoothly to convert into the corresponding products in
moderate to excellent yields. Though the formation of regio-
isomers is unavoidable due to 1,4-palladium migration for the
substrates of 4-substituted o-bromoiodobenzenes, this one-pot,
multistep reaction is still an appealing strategy and might find
application in the synthesis of polycyclic aromatic hydrocarbons
(PAHs) because of its straightforward, practical and step
economy.
6j
64%.
6i
83%
n.d.
trace
H3C
CH
3 H3CO
OCH
3 F3C
CF3
6k
6l
n.d.
CH3 H3COOC
78%.
62%
O
O
H3COOC
Ph
n-C4H9
CH3
Ph
CH3
O
O
6o
30%
6m
76%
6n
57%
n.d.
trace
a
1a
2b 5
(0.3 mmol), (0.75 mmol), Pd(OAc)2 (0.015 mmol),
Reaction Conditions:
(0.3 mmol),
oC
DPEphos (0.03 mmol), Cs2CO3 (0.6 mmol), PivOH (0.3 mmol) in toluene (2 mL) at 120
for 24 h. isolated yield.
Acknowledgements
This work was supported by the National Natural Science
Foundation of China (21673261, 21603245, 21703265 and
21573111), Key Laboratory of Organic Synthesis of Jiangsu
Province (KJS1747), the Funding from Nanjing University of Posts
and Telecommunications (NY217072, NY215016, NY215079).
Br
Pd(OAc)2
DPEphos
+
Ph
Ph
Cs2CO3, PivOH
120 o
24h
C
,
4a
92%
Scheme 3. The annulation reaction of 2-bromo-4‘-methyl-1,1'-
biphenyl under the standard condition
Conflicts of interest
There are no conflicts to declare.
6i) in high yield (80-88%), which revealed that the electronic
properties of substituents at the para positions had marginal
influence on the transformation efficiency. However, the steric and
electronic nature of the substituents at ortho position on the phenyl
ring had a great influence on the reaction and only CH3 group at 2-
position afforded the corresponding phenanthrene (6j) in 64% yield.
Notes and references
1. R. Mitsuhashi, Y. Suzuki, Y. Yamanari, H. Mitamura, T. Kambe, N.
Ikeda, H. Okamoto, A. Fujiwara, M. Yamaji, N. Kawasaki, Y.
Maniwa and Y. Kubozono, Nature, 2010, 464, 76-79.
4 | J. Name., 2012, 00, 1-3
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2. M. G. Banwell, A. Bezos, C. Burns, I. Kruszelnicki, C. R. Parish, S.
Su and M. O. Sydnes, Bioorg Med Chem Lett, 2006, 16, 181-185.
3. Z. Xi, R. Zhang, Z. Yu, D. Ouyang and R. Huang, Bioorg Med Chem
Lett, 2005, 15, 2673-2677.
4. F. Xu, G. Li, J. Ma, Y. Qiao, J. Tu and S. Liu, Synlett, 2015, 26, 1991-
1996.
5. A. Matsumoto, L. Ilies and E. Nakamura, Journal of the American
Chemical Society, 2011, 133, 6557-6559.
6. T. Shibata, Y. Ueno and K. Kanda, Synlett, 2006, 2006, 0411-0414.
Chemistry, an Asian journal, 2012, 7, 1644-1651.
View Article Online
35. S. A. Worlikar and R. C. Larock, The Journal of organic chemistry,
DOI: 10.1039/C9OB00228F
2009, 74, 9132-9139.
36. Y. H. Kim, H. Lee, Y. J. Kim, B. T. Kim and J. N. Heo, The Journal of
organic chemistry, 2008, 73, 495-501.
37. D. Peña, D. Pérez, E. Guitián and L. Castedo, Journal of the
American Chemical Society, 1999, 121, 5827-5828.
38. K. V. Radhakrishnan, E. Yoshikawa and Y. Yamamoto,
ChemInform, 2010, 31.
7. Y. Yamamoto, K. Matsui and M. Shibuya, Chemistry, 2015, 21, 39. E. Yoshikawa and Y. Yamamoto, ChemInform, 2010, 31, no-no.
7245-7255.
40. A. A. Cant, L. Roberts and M. F. Greaney, Chemical
communications, 2010, 46, 8671-8673.
8. Y. Kwon, H. Cho and S. Kim, Org Lett, 2013, 15, 920-923.
9. H. C. Shen, J. M. Tang, H. K. Chang, C. W. Yang and R. S. Liu, The 41. Z. Liu and R. C. Larock, Angewandte Chemie, 2007, 46, 2535-2538.
Journal of organic chemistry, 2005, 70, 10113-10116.
10. R. Jin, Y. Chen, W. Liu, D. Xu, Y. Li, A. Ding and H. Guo, Chemical
communications, 2016, 52, 9909-9912.
11. V. Mamane, P. Hannen and A. Furstner, Chemistry, 2004, 10,
4556-4575.
42. M. Iwasaki, Y. Araki and Y. Nishihara, The Journal of organic
chemistry, 2017, 82, 6242-6258.
43. G. Dyker and A. Kellner, Tetrahedron Letters, 1994, 35, 7633-
7636.
44. M. Catellani, E. Motti and S. Baratta, Org Lett, 2001, 3, 3611-3614.
12. A. Fürstner and V. Mamane, The Journal of organic chemistry, 45. Q. Zhao, W. C. Fu and F. Y. Kwong, Angewandte Chemie, 2018,
2002, 67, 6264-6267. 57, 3381-3385.
13. J. Carreras, G. Gopakumar, L. Gu, A. Gimeno, P. Linowski, J. 46. J. Zhao, N. Asao, Y. Yamamoto and T. Jin, Journal of the American
Petuskova, W. Thiel and M. Alcarazo, Journal of the American
Chemical Society, 2013, 135, 18815-18823.
14. Y. Xia, Z. Liu, Q. Xiao, P. Qu, R. Ge, Y. Zhang and J. Wang,
Angewandte Chemie, 2012, 51, 5714-5717.
Chemical Society, 2014, 136, 9540-9543.
47. H. E. Ho, T. C. Stephens, T. J. Payne, P. O’Brien, R. J. K. Taylor and
W. P. Unsworth, ACS Catalysis, 2018, 9, 504-510.
48. G. Liu and X. Lu, Tetrahedron Letters, 2002, 43, 6791-6794.
15. T. Matsuda, K. Kato, T. Goya, S. Shimada and M. Murakami, 49. L. Bai, J. Liu, W. Hu, K. Li, Y. Wang and X. Luan, Angewandte
Chemistry, 2016, 22, 1941-1943.
Chemie, 2018, 57, 5151-5155.
16. A. Iuliano, P. Piccioli and D. Fabbri, Org Lett, 2004, 6, 3711-3714.
17. K. Bera, S. Sarkar, S. Jalal and U. Jana, The Journal of organic
chemistry, 2012, 77, 8780-8786.
18. C. C. McAtee, P. S. Riehl and C. S. Schindler, Journal of the
American Chemical Society, 2017, 139, 2960-2963.
19. C. Wang, S. Rakshit and F. Glorius, Journal of the American
Chemical Society, 2010, 132, 14006-14008.
20. Y. D. Lin, C. L. Cho, C. W. Ko, A. Pulte and Y. T. Wu, The Journal of
organic chemistry, 2012, 77, 9979-9988.
21. W. Matsuoka, H. Ito and K. Itami, Angewandte Chemie, 2017, 56,
12224-12228.
22. D. Wan, X. Li, R. Jiang, B. Feng, J. Lan, R. Wang and J. You, Org
Lett, 2016, 18, 2876-2879.
23. R. C. Larock, M. J. Doty, Q. P. Tian and J. M. Zenner, Journal of
Organic Chemistry, 1997, 62, 7536-7537.
24. M. Miura, T. Satoh, T. Nagata and Y. Nishii, Synlett, 2016, 27,
1707-1710.
25. T. Nagata, K. Hirano, T. Satoh and M. Miura, The Journal of
organic chemistry, 2014, 79, 8960-8967.
26. J. Yan and N. Yoshikai, Org Lett, 2017, 19, 6630-6633.
27. K. Ozaki, W. Matsuoka, H. Ito and K. Itami, Org Lett, 2017, 19,
1930-1933.
28. Y. Wu, F. Wu, D. Zhu, B. Luo, H. Wang, Y. Hu, S. Wen and P. Huang,
Organic & biomolecular chemistry, 2015, 13, 10386-10391.
29. K. Ozaki, K. Murai, W. Matsuoka, K. Kawasumi, H. Ito and K. Itami,
Angewandte Chemie, 2017, 56, 1361-1364.
30. A. Korotvicka, I. Cisarova, J. Roithova and M. Kotora, Chemistry,
2012, 18, 4200-4207.
31. M. Shimizu, I. Nagao, Y. Tomioka and T. Hiyama, Angewandte
Chemie, 2008, 47, 8096-8099.
32. M. Shimizu and T. Hiyama, European Journal of Organic
Chemistry, 2013, 2013, 8069-8081.
33. M. Shimizu, I. Nagao, Y. Tomioka, T. Kadowaki and T. Hiyama,
Tetrahedron, 2011, 67, 8014-8026.
34. M. Shimizu, Y. Tomioka, I. Nagao, T. Kadowaki and T. Hiyama,
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DOI: 10.1039/C9OB00228F
A Palladium-Catalyzed Multi-Component Annulation Approach towards
Synthesis of Phenanthrenes
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DPEphos
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+
+
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24h
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