Palladium(II) catalyzed oxidative functionalization of c h bonds using alkyne as building block

PALLADIUM(II)-CATALYZED
OXIDATIVE FUNCTIONALIZATION OF C-H BONDS
USING ALKYNE AS BUILDING BLOCK




PENG SHI-YONG
（B. Sc. Nankai University）





A THESIS SUBMITTED
FOR THE DEGREE OF DOCTOR OF PHILOSOPHY
DEPARTMENT OF CHEMISTRY
NATIONAL UNIVERSITY OF SINGAPORE



2014

I

Declaration
I hereby declare that this thesis is my original work and it has been written by me in
its entirety, under the supervision of Dr. Wang Jian, Chemistry Department, National
University of Singapore, between Aug. 2010 and Aug. 2014.

I have duly acknowledged all the sources of information which have been used in the
thesis.
This thesis has also not been submitted for any degree in any university previously.
The content of the thesis has been published in:
1) S. Y. Peng, T. Gao, S. F. Sun, Y. H. Peng, M. H. Wu, H. B. Guo, J. Wang*, Adv.
Synth. Catal. 2014, 356, 319.
2) S. Y. Peng, L. Wang, J. Wang*, Chem. Eur. J. 2013, 19, 13322.
3) S. Y. Pe ng , L. Wang, J. Y. Huang, S. F. Sun, H. B. Guo, J. Wang*, Adv. Synth.
Catal. 2013, 355, 2550.
4) S. Y. Peng, L. Wang, H. B. Guo, S, F. Sun, J. Wang*, Org. Biomol. Chem.
2012, 10, 2537.
5) S. Y. Peng, L. Wang, J. Wang*, Org. Biomol. Chem. 2012, 10, 225.


Name Signature Date

II

Acknowledgements
It is my great pleasure to take this opportunity to express my gratitude and thanks
to all the people who have helped and encouraged me during my Ph.D. studies. Noth-
ing in this thesis would have been possible without each and every one of you. Thank
you!
First and foremost, I want to express my deepest respect and most sincere grati-
tude to my supervisor, Prof. Dr. Wang Jian, for offering me the great opportunity to
be his Ph.D. student and guiding me to the intriguing and challenging field of palla-
dium chemistry. Dr. Wang is a great supervisor to me. He has great passion and en-
thusiasm for chemistry, even when it did not want to cooperate. I would like to thank
him for supporting me, teaching me and guiding me within the chemistry community,
and thanks for encouraging me in my ambitions. His broad knowledge, enthusiasm,

inspiration and dedication to science will with no doubt benefit me through all my life.
His believing in me as a chemist gives me the confidence to go forward to further
pursue my research career.
Next, I wish to express my warm and sincere thanks to my senior, Dr. Wang Lei,
who has helped me enormously with my research projects in National University of
Singapore. Our extensive discussion has been very helpful for me to understand what
the problem was and how to solve it. This thesis would be impossible without his
generous help. Besides, I also want to give my great appreciation to another senior,
Miss Ren Q iao, for her valuable advice and friendly help, although we have focused

III

on different research fields.
I would like to thank all my lab mates in Dr. Wang’s lab, past and present, our
postdoctors: Dr. Gao Yao-Jun, Dr. Xue Fei and Dr. Li Wen-Jun, our Masters: Huang
Yuan, Wang Peng-Cheng, Lu Xian, Xiao Dan and Xue Cheng-Wen, our lovely and
active Honours: N g Hui-Fen, Siaw Woon-Ye w etc., whose effective collaboration,
helpful discussion and friendship have greatly helped me during my four years’ life
and studies.
I also want to thank the research scholarship provided by National University of
Singapore. In addition, I want to extend my gratitude to all the laboratory staff of our
chemistry department, particularly Madam Ta n Geok-Kheng and Madam Hong
Yi-Mian for X-ray crystallography analysis, Madam Han Yan-Hui and Dr. Wu Ji-En
for NMR training and testing, Madam Wong Lai-Kwai and Madam Liu Q i-Ping for
mass analysis. Thanks also go to the administrative and technical staff, especially
Mada m Suriawati Binte Sa’Ad in our department administrative office, Mr. Lee
Yoo n-Kuang, Mr. Phua Wei-De Victor and Mr.
Soffiyan Bin Hamzah in our lab supply
store.
I would also like to express my sincere thanks to all my friends in Singapore for

their help during the past four years. I will definitely miss and treasure their friend-
ships.
Finally, my deepest gratitude goes to my family for their unflagging love and
support throughout my life. THANK YOU!

IV

Table of Contents
Declaration I
Acknowledge ments II
Table of Contents IV
Summary IX
List of Tables XI
List of Figures XIII
List of Schemes XIV
List of Abbreviations XIX
List of Publications XXIII
Chapter 1 Introduction 1
1.1 Transition-Metal-Catalyzed C-H Bond Functionalization 1
1.2 Traditional Pd(0)-Catalyzed Cross-Coupling Reactions 7
1.3 Modern Pd-Catalyzed C-H Functionalization Reactions 12
1.3.1 C-H Bond Functionalization via Pd(0)/Pd(II) Catalysis 13
1.3.2 C-H Bond Functionalization via Pd(II)/Pd(IV) Catalysis 15
1.3.3 C-H Bond Functionalization via Pd(0)/Pd(II)/Pd(IV) Catalysis 18
1.3.4 C-H Bond Functionalization via Pd(II)/Pd(0) Catalysis 20
1.4 Pd-Catalyzed Alkyne Transformation via C-H Functionalization 27
1.4.1 Pd-Catalyzed Alkynylation Reactions 28
1.4.2 Pd-Catalyzed Alkyne Cycloaromatization Reactions 39
1.5 Project Objectives 49

V

Chapter 2 Palladium-Catalyzed [2+2+1] Oxidative Annulation of
4-Hydroxycoumarins with Unactivated Internal Alkynes: Access to Spiro
Cyclopentadiene-chroman-2,4-dione Complexes 52
2.1 Introduction 53
2.2 Results and Discussion 54
2.3 Conclusion 60
2.4 Experimental Section 61
2.4.1 General Information 61
2.4.2 Preparation and Characterization of Compounds 2-3 62
2.4.3 Preparation and Characterization of Compounds 2-4 74
2.4.4 Preparation and Characterization of Compound 2-5 79
2.4.5 Preparation and Characterization of Compound 2-6 80
2.4.6 X-ray Crystallographic Analysis 80
Chapter 3 Palladium-Catalyzed Oxidative Annulation via C–H/N–H
Functionalization: Access to Substituted Pyrroles 84
3.1 Introduction 85
3.2 Results and Discussion 87
3.3 Conclusion 93
3.4 Experimental Section 94
3.4.1 General Information 94
3.4.2 Preparation and Characterization of Compounds 3-3 95
3.4.3 Preparation and Characterization of Compound 3-4 110

VI

3.4.4 Preparation and Characterization of Compound 3-5 110
3.4.5 X-ray Crystallographic Analysis 111
Chapter 4 Direct Access to Highly Substituted 1-Naphthols through

Palladium-Catalyzed Oxidative Annulation of Benzoylacetates and Internal
Alkynes 115
4.1 Introduction 116
4.2 Results and Discussion 118
4.2.1 Reaction Optimization 118
4.2.2 Substrate Scope 119
4.2.3 Competition Experiments 122
4.2.4 Synthetic Transformations 123
4.2.5 Mechanistic Investigation 126
4.3 Conclusion 127
4.4 Experimental Section 128
4.4.1 General information 128
4.4.2 Preparation and Characterization of Compounds 4-3 129
4.4.3 Intermolecular Competition Experiments 148
4.4.4. Kinetic Study 150
4.4.5 Large Scale Application 151
4.4.6 Preparation and Characterization of Compound 4-4 152
4.4.7 Preparation and Characterization of Compound 4-5 153
4.4.8 Preparation and Characterization of Compound 4-6 154

VII

4.4.9 Preparation and Characterization of Compound 4-7 155
4.4.10 Preparation and Characterization of Compound 4-8 156
4.4.11 Preparation and Characterization of Compound 4-9 157
4.4.12 Preparation and Characterization of Compound 4-10 158
4.4.13 Preparation and Characterization of Compound 4-11 159
4.4.14 Preparation and Characterization of Compound 4-12 160
4.4.15 Preparation and Characterization of Compound 4-13 161
4.4.16 X-ray Crystallographic Analysis 162

Chapter 5 Iron-catalyze d Ene-type Propargylation of Diarylethylenes with
Propargyl Alcohols 164
5.1 Introduction 165
5.2 Results and Discussion 166
5.3 Conclusion 172
5.4 Experimental Section 172
5.4.1 General Information 172
5.4.2 Preparation and Characterization of Compounds 5-3 173
5.4.3 X-ray Crystallographic Analysis 187
Chapter 6 Facile Synthesis of 4-Substituted 3,4-Dihydrocoumarins via an
Organocatalytic Double Decarboxylation Process 189
6.1 Introduction 190
6.2 Results and Discussion 192
6.3 Conclusion 198

VIII

6.4 Experimental Section 198
6.4.1 General Information 198
6.4.2 Preparation and Characterization of Compounds 6-3 199
References 208
1
H NMR and
13
C NMR Spectra of Major Compounds………………………….228



IX

Summary
One of the over-arching goals of the research in Dr. Wang’s lab is to develop
methodologies for the regioselective and diverse functionalization of C–H bonds. The
Pd(II)-catalyzed C-H activation/functionalization organic transformations have be-
come a practical and powerful tool in organic chemistry. This thesis describes my ef-
forts during my Ph.D. research for Pd(II)-catalyzed C–H functionalization reactions
that result in the formation of many biologically and pharmaceutically important
molecules utilizing alkyne as a universal building block.
Chapter 1 gave a brief introduction of transition metal catalysis, followed by a
general evaluation of the research progress of Pd-chemistry, particularly Pd-mediated
alkyne transformations, which were elucidated with selected examples.
Chapter 2 described an efficient synthesis of an interesting spiro cyclopentadi-
ene-chroman-2,4-dione heterocycles. The method employed a direct Pd(II)-catalyzed
oxidative [2+2+1] cycloaddition of readily available starting materials:
4-hydroxycoumarins and unactivated internal alkynes. Various substituents were well
tolerated in the reaction, which led to a number of unique molecular structures.
Chapter 3 developed an efficient synthesis of highly substituted pyrroles. The
method utilized simple and readily available enamines and alkynes, and employed
direct Pd(II)-catalyzed oxidative annulation procedure. A mechanistic investigation of
pyrro le-forming reaction established a viable catalytic cycle. The mild nature of the
reaction and the significance of the pyrrole scaffold as structural element should ren-

X

der this method attractive for both synthetic and medicinal chemistry.
Chapter 4 disclosed an efficient synthesis of highly substituted 1-naphthols. The
method utilized simple and readily available benzoylacetates and unactivated internal
alkynes as starting materials, and employed a direct Pd(II)-catalyzed oxidative annu-
lation procedure involving C-H activation. The mild nature of the reaction, functional
group compatibility and the significance of the 1-naphthol scaffold as structural ele-

ment should render this method attractive in different disciplines.
The diarylalkenyl propargylic complex framework has been found in many nat-
ural products and medicinal regents. In chapter 5, an unprecedented Fe-catalyzed
ene-type reaction of propargylic alcohols with 1,1-diaryl alkenes was developed,
which enabled us to furnish a diarylalkenyl propargylic complex in moderate to high
chemical yields.
3,4-Dihydrocoumarins have attracted considerable attention due to their various
biological activities. In chapter 6, we have documented an efficient and convenient
double decarboxylation process for the synthesis of 4-substituted
3,4-dihydrocoumarins in moderate to excellent yields under metal-free reaction con-
ditions.


XI

List of Tables
Table 1.1 Traditional Pd(0)-catalyzed cross-coupling reactions
Table 2.1 Optimization of reaction conditions
Table 2.2 Substrate scope of 4-hydroxycoumarins
Table 2.3 Substrate scope of alkynes
Table 2.4 Synthesis of furo[3,2-c]coumarins
Table 2.5 Crystal data and structure refinement for 2-3aa
Table 2.6 Crystal data and structure refinement for 2-4aa
Table 3.1 Optimization of reaction conditions
Table 3.2 Substrate scope of 4-aminocoumarins
Table 3.3 Substrate scope of symmetric alkynes
Table 3.4 Substrate scope of asymmetric alkynes
Table 3.5 Crystal data and structure refinement for 3-3da
Table 3.6 Crystal data and structure refinement for 3-5
Table 4.1 Optimization of the reaction conditions

Table 4.2 Substrate scope of β-ketoesters
Table 4.3 Substrate scope of internal alkynes
Table 4.4 Crystal data and structure refinement for 4-3oa
Table 5.1 Investigation of ene-type reactions
Table 5.2 Investigation of catalysts
Table 5.3 Optimization of other parameters
Table 5.4 Substrate scope of propargylic alcohols

XI I

Table 5.5 Substrate scope of diarylethylenes
Table 5.6 Crystal data and structure refinement for 5-3ap
Table 6.1 Investigation of catalysts
Table 6.2 Optimization of reaction conditions
Table 6.3 Substrate scope of coumarin-3-carboxylic acids
Table 6.4 Substrate scope of malonic acid half-thioesters
Table 6.5 Substrate scope of α-functionalized carboxylic acids


XIII

List of Figures
Figure 2.1 X-ray structure of 2-3aa
Figure 2.2 X-ray structure of 2-4aa
Figure 3.1 Examples of pyrrole pharmaceuticals
Figure 3.2 X-ray structure of 3-3da
Figure 3.3 X-ray structure of 3-5
Figure 4.1 Important examples of substituted 1-naphthols
Figure 4.2 X-ray structure of 4-3oa
Figure 5.1 X-ray structure of 5-3ap

Figure 6.1 Examples of 3,4-dihydrocoumarin based natural products



XI V

List of Schemes
Scheme 1.1 Traditional functional-group-based transformatio n vs transi-
tion-metal -catalyzed C-H bond functionalization
Scheme 1.2 C-H bond functionalization of azobenzene by stoichiometric transi-
tion metal complex Cp
2
Ni
Scheme 1.3 C-H bond functionalization by catalytic transition metal complexes
Scheme 1.4 ‘Inner-sphere’ mechanism of C-H activation
Scheme 1.5 ‘Outer-sphere’ mechanism of C-H activation
Scheme 1.6 Gaunt’s iterative Cu-catalyzed arylation methodology of anilines
Scheme 1.7 Yu’s end-on-template-directed meta-selective C-H functionalizaiton
Scheme 1.8 Mechanisms for Pd(0)-catalyzed cross-coupling reactions
Scheme 1.9 C-H bond cleavage of electron-rich heterocycles via Pd(0)/Pd(II)
catalysis
Scheme 1.10 C-H bond activation of non-heterocycles via Pd(0)/Pd(II) catalysis
Scheme 1.11 Pd(0)/Pd(II) catalytic cycle
Scheme 1.12 ortho-Methylation of anilide via Pd(II)/Pd(IV) catalytic cycle
Scheme 1.13 X-ray structures of Pd(IV) complexes
Scheme 1.14 Pd(II)/Pd(IV) catalytic cycle
Scheme 1.15 C-H bond arylation via Pd(II)/Pd(IV) catalytic cycle
Scheme 1.16 C-H bond activation via Pd(II)/Pd(IV) catalytic cycle by Sanford
Scheme 1.17 C-H bond arylation using ArI via Pd(II)/Pd(IV) catalytic cycle by
Daugulis

XV

Scheme 1.18 Catellani reaction: Pd(0)/Pd(II)/Pd(IV) catalysis
Scheme 1.19 Pd(0)/Pd(II)/Pd(IV) catalysis without norbornene by Dyker
Scheme 1.20 Three types of mechanisms of C-H bond activation via Pd(II)/Pd(0)
catalysis
Scheme 1.21 Initial report of oxidative olefination via Pd(II)/Pd(0) catalysis
Scheme 1.22 Directed ortho-olefination via Pd(II)/Pd(0) catalysis
Scheme 1.23 Selective olefination strategies via Pd(II)/Pd(0) catalysis
Scheme 1.24 meta-Olefination strategy via Pd(II)/Pd(0) catalysis
Scheme 1.25 Oxazoline-directed ortho-C-H activation via Pd(II)/Pd(0) catalysis
Scheme 1.26 Directed ortho-C-H activation via Pd(II)/Pd(0) catalysis
Scheme 1.27 C-H Activation of active olefins and (hetero)arenes via Pd(II)/Pd(0)
catalysis
Scheme 1.28 Oxidative homocoupling of thiophenes via Pd(II)/Pd(0) catalysis
Scheme 1.29 Oxidative arene-arene cross-coupling via Pd(II)/Pd(0) catalysis
Scheme 1.30 Pd-Catalyzed symmetrical 1,3-diyne formation
Scheme 1.31 Pd-Catalyzed unsymmetrical 1,3-diyne formatio n
Scheme 1.32 Pd-Catalyzed 1,3-enyne formation via Sonogashira reaction
Scheme 1.33 Pd-Catalyzed 1,3-enyne formatio n via alkyne dimerization
Scheme 1.34 Pd-Catalyzed 1,3-enyne formation via oxidative coupling of alkynes
and alkenes
Scheme 1.35 Pd-Catalyzed 1,3-enyne formation via other strategies
Scheme 1.36 Pd-Catalyzed direct alkynylation of heteroaromatic compounds

XVI

Scheme 1.37 Pd-Catalyzed oxidative alkynylation of heterocycles
Scheme 1.38 Pd-Catalyzed direct alkynylation of arenes

Scheme 1.39 Pd-Catalyzed oxidative alkynylation of arenes
Scheme 1.40 Pd-Catalyzed alkynylation of alkanes
Scheme 1.41 Naphthalene and phenanthrene formation via Pd(0)-catalyzed cyclo-
aromatization of alkynes and iodobenzenes
Scheme 1.42 Phenanthrene formation via Pd(0)-catalyzed cycloaromatization of
alkynes
Scheme 1.43 Benz[a]anthracene formation via Pd(0)-catalyzed cycloaromatiza-
tion of alkynes
Scheme 1.44 Benzene formation via Pd(II)-catalyzed oxidative cycloaromatiza-
tion of alkynes and alkenes
Scheme 1.45 Naphthalene formation via Pd(II)-catalyzed oxidative cycloaromati-
zation of alkynes
Scheme 1.46 PAHs via Pd(II)-catalyzed oxidative cycloaromatization of alkynes
Scheme 1.47 Traditional Pd(0)-catalyzed heterocarbocycle formation
Scheme 1.48 Indole synthesis via Pd(II)-catalyzed oxidative cycloaromatization
of alkynes
Scheme 1.49 Indole-fused carbocycles via Pd(II)-catalyzed oxidative cycloaroma-
tizatio n of alkynes by Jiao
Scheme 1.50 Carbazole formation via Pd(II)-catalyzed oxidative cycloaromatiza-
tion of alkynes by Miura

XVI I

Scheme 1.51 Heteroaromatic hydrocarbon formation via Pd(II)-catalyzed oxida-
tive cycloaromatization of alkynes
Scheme 1.52 Polyarylated (hetero)aromatic compounds formation via
Pd(II)-catalyzed oxidative annulation of alkynes
Scheme 1.53 Initia l try for Fe-catalyzed and metal-free reactions
Scheme 2.1 Pd-catalyzed cascade reactions of 4-hydroxycoumarins with internal
alkynes

Scheme 2.2 Cyclic ketone as substrate
Scheme 2.3 Plausible mechanism
Scheme 2.4 Plausible mechanism
Scheme 2.5 Transformations of compound 2-4aa
Scheme 3.1 Transitio n-metal-catalyzed pyrrole synthesis
Scheme 3.2 Initial try
Scheme 3.3 Substrate scope of N-protected 4-aminocoumarin and β-enaminones
Scheme 3.4 Synthetic transformations of compound 3-3aa
Scheme 3.5 Plausible mechanism
Scheme 4.1 Challenges in the synthesis of 1-naphthols
Scheme 4.2 Competition experiments
Scheme 4.3 Synthetic transformations of compound 4-3aa
Scheme 4.4 Synthetic transformations of compound 4-4
Scheme 4.5 Gram-scale synthesis of 4-3aa
Scheme 4.6 Kinetic study

XVIII

Scheme 4.7 Plausible mechanism
Scheme 5.1 Propargylation methods
Scheme 5.2 Proposed catalytic cycle
Scheme 6.1 Approaches to 3,4-dihydrocoumarins
Scheme 6.2 Control experiments



XI X

List of Abbreviations
Ac Acetyl

Ac
2
O Acetic anhydride
4Å MS 4Å molecula r seives
Ar Aryl
Boc tert-Butyloxycarbonyl
Bz Benzoyl
Bn Benzyl
Bu Butyl
BQ Benzoquinone
BINAP 2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl
CH
3
CN Acetonitrile
CH
3
NO
2
Nitromethane
Cp
2
Ni Nickelocene
CO Carbon monoxide
DG Directing group
DCE 1,2-Dichloroethane
DMSO Dimethyl sulfoxide
DMA Dimethylacetamide
DMF Dimethylformamide
DME Dimethoxyethane
DCM Dichloro metha ne

XX

DIPEA N,N-Diisopropylethylamine
DMAP 4-Dimethylaminopyridine
dppp 1,3-Bis(diphenylphosphino)propane
DTPF 1,1′-Bis[di(p-tolyl)phosphino]ferrocene
d-i-Prpf 1,1′-Bis(diisopropylphosphino)ferrocene
DDQ 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone
Et Ethyl
Et
2
O Diethyl ether
EtOAc or EA Ethyl acetate
EWG Electron withdrawing group
EDG Electron donating group
EI Electron ioniztio n
ESI Electrospray ionization
FG Functional group
HOAc Acetic acid
HMPT Hexamethylphosphorous triamide
HRMS High resolutio n mass spectrometry
KIE Kinetic isotope effect
LiHMDS Lithium bis(trimethylsilyl)amide
Me Methyl
Mes Mesitylene
MW Microwave

XXI

N
2
Nitrogen

Nu Nucleophile
NMP N-Methyl-2-pyrrolidone
NHC N-Heterocyclic carbene
NMR Nuclear magnetic resonance
O
2
Oxygen
Pr Propyl
Piv Pivaloyl
PMP p-Methoxyphenyl
PPh
3
Triphenylphosphine
PCy
3
Tricyclohexylphosphine
PivOH Pivalic acid
r.t. or R. T. Room temperature
Tf Triflyl
OTf Triflate
Ts p-Tosyl
OTs p-Tosylate
TFA Trifluoroacetic acid
TASF Tris(dimethylamino)sulfonium difluorotrimethylsilicate
TDMPP Tris(2,6-dimethoxyphenyl)phosphine
TBAF Tetra-n-butylammonium fluoride

TBAC Tetra-n-butylammo nium chloride

XXI I

TBAB Tetra-n-butylammonium bromide
TEA Triethyl amine
TMS Trimethylsilyl
TIPS Triisopropylsilyl
THF Tetrahydrofuran
TLC Thin layer chromatography
UV Ultraviolet


XXI II

List of Publications
1. “Palladium-Catalyzed [2+2+1] Oxidative Dearomatizative Annulation of Ani-
soles with Unactivated Internal Alkynes”, S. Y. Peng, L. Wang, J. Wang*, Man-
uscript in preparation.
2. “Palladium-Catalyzed [2+2+1] Decarboxylative Annulation of Cinnamic acids
with Unactivated Internal Alkynes: Access to Pentafulvene Derivatives”, S. Y.
Peng, L. Wang, J. Wang*, Manuscript in preparation.
3. “Palladium-Catalyzed [2+2+1] Oxidative Annulation of 4-Hydroxycoumarins
with Unactivated Internal Alkynes: Access to Spiro Cyclopentadi-
ene-Chroman-2,4-dione Complexes”, S. Y. Peng, T. Gao, S. F. Sun, Y. H. Peng,
M. H. Wu, H. B. Guo, J. Wang*, Adv. Synth. Catal. 2014, 356, 319.
4. “Direct Access to Highly Substituted 1-Naphthols through Palladium-Catalyzed
Oxidative Annulation of Benzoylacetates and Internal Alkynes”, S. Y. Peng, L.
Wang, J. Wang*, Chem. Eur. J. 2013, 19, 13322.
5. “Palladium-Catalyzed Oxidative Annulation via C-H/N-H Functionalization:

Access to Substituted Pyrroles”, S. Y. Peng, L. Wang, J. Y. Huang, S. F. Sun, H.
B. Guo, J. Wang*, Adv. Synth. Catal. 2013, 355, 2550.
6. “Facile Synthesis of 4-Substituted 3,4-Dihydrocoumarins via an Organocatalytic
Double Decarboxylation Process”, S. Y. Peng, L. Wang, H. B. Guo, S, F. Sun, J.
Wang*, Org. Biomol. Chem. 2012, 10, 2537.
7. “Iron-Catalyzed Ene-type Propargylation of Diarylethylenes with Propargyl Al-
cohols”, S. Y. Peng, L. Wang, J. Wang*, Org. Biomol. Chem. 2012, 10, 225.

XXI V

8. “Palladium-Catalyzed Cascade Reactions of Coumarins with Alkynes: Synthesis
of Highly Substituted Cyclopentadiene Fused Chromones”, L. Wang, S. Y. Peng,
J. Wang*, Chem. Commun. 2011, 47, 5422. (Back Cover)
9. “Amine-Catalyzed [3+2] Huisgen Cycloaddition Strategy for the Efficient As-
sembly of Highly Substituted 1,2,3-Triazoles”, L. Wang, S. Y. Peng, J. T. Lee
Danence, Y. J. Gao, J. Wang*, Chem. Eur. J. 2012, 18, 6088. (Highlight in
SYNFACT)
10. “Palladium-Catalyzed Oxidative Cycloaddition through C-H/N-H Activation:
Access to Benzazepines”, L. Wang, J. Y. Huang, S. Y. Peng, H. Liu, X. F. Jiang*,
J. Wang*, Angew. Chem. Int. Ed. 2013, 52, 1768.