Gold-Catalyzed Tandem Oxidative Coupling Reaction between β-Ketoallenes and Electron-Rich Arenes to 2-Furylmethylarenes

Article abstract of DOI:10.1021/acs.orglett.1c02007

A tandem oxidative coupling reaction of β-ketoallenes and arenes was developed, which leads to the formation of 2-furylmethylarenes using AuCl3 and phenyliodine diacetate. The AuIII salt catalyzed the cyclization of β-ketoallenes to form a 2-furylmethyl gold intermediate, and the subsequent C-H functionalization of arenes proceeded smoothly. During the oxidative coupling, nucleophilic additions occurred at the center and terminal carbon atoms of the allene moiety to form C-O and C-C bonds.

Full text of DOI:10.1021/acs.orglett.1c02007

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Letter
Gold-Catalyzed Tandem Oxidative Coupling Reaction between
β‑Ketoallenes and Electron-Rich Arenes to 2‑Furylmethylarenes
Naoki Yasukawa,* Yutaro Yamada, Chikara Furugen, Yuya Miki, Hironao Sajiki, and Yoshinari Sawama*
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sı Supporting Information
ABSTRACT: A tandem oxidative coupling reaction of β-ketoallenes
and arenes was developed, which leads to the formation of 2-
III
furylmethylarenes using AuCl and phenyliodine diacetate. The Au
3
salt catalyzed the cyclization of β-ketoallenes to form a 2-furylmethyl
gold intermediate, and the subsequent C−H functionalization of arenes
proceeded smoothly. During the oxidative coupling, nucleophilic
additions occurred at the center and terminal carbon atoms of the
allene moiety to form C−O and C−C bonds.
11a−c
11d
iarylmethanes are ubiquitous and important chemical
acids
or aryl silanes
using Selectfluor as an oxidant
B
motifs for various functional materials, such as biologically
has been accomplished to afford 2-arylmethyl-substituted
1
active compounds, pharmaceuticals, and polymers. Among
them, 2-furylmethylarenes as furan-based biarylmethane
heterocyclic compounds (Scheme 1C). Photoredox/gold
1
2
I
III
dual catalysis using aryl diazonium salts and a Au /Au
2
−4
13
derivatives also exhibit useful bioactivities (Scheme 1A).
catalytic system with P and N ligands and aryl iodides has
also been applied to the oxi/amino-arylation of alkenes.
Herein, we demonstrate a novel synthetic method for 2-
Gold salt catalysts possessing the π-activation ability of C−C
multiple bonds have emerged as powerful tools for accessing
various heterocyclic skeletons via the intramolecular cyclization
of alkynyl or allenyl substrates bearing heteroatoms (hydroxy
and carbonyl functionalities) within the same molecule.
Ketoallenes also could undergo the gold-catalyzed intra-
furylmethylarenes (2) via the gold (AuCl )-catalyzed cyclo-
3
isomerization of β-ketoallenes (1) and subsequent C−H
functionalization of arenes (benzene and indole derivatives)
in the presence of phenyliodine diacetate (PIDA) as an oxidant
5
−8
β-
6
molecular cyclization to provide multisubstituted furans.
(
Scheme 1D). During the oxidative coupling presented here,
These traditional gold-catalyzed reactions have been applied
to construct complicated 2-furylmethylarenes by using tandem
reactions. Some examples of such reactions are the intra-
molecular cyclization of 1-oxiranyl-2-alkynyl acetates and the
subsequent Friedel−Crafts arylation (Scheme 1B-a), as well
as the cyclization of N-(2-alkynylphenyl)imines accompanied
the allenyl moiety acted as a bis-electrophile. The double
nucleophilic substitutions at the center and terminal carbon
atoms of β-ketoallenes (1) occurred in tandem to form C−O
and C−C bonds.
The reaction conditions for the synthesis of a 2-
furylmethylbenzene derivative (2a) using 1-phenylpenta-3,4-
dien-1-one (1a) as a β-ketoallene substrate and 1,3,5-
trimethoxybenzene (5 equiv) as an arene nucleophile were
7
by the addition of vinyldiazo ketones and the subsequent furan
ring construction via 1,3-group migration (Scheme 1B-b).
8
I
III
Meanwhile, the Au /Au catalytic system using additional
oxidants can achieve a remarkable intermolecular cross-
coupling reaction based on the oxidative C−H functionaliza-
optimized (Table 1). The reaction using AuCl (10 mol %) in
3
CH Cl (0.4 M) at room temperature for 24 h afforded the
2
2
desired product (2a) in 38% yield, along with the formation of
-methyl-5-phenylfuran (3a) in 41% yield as a protonated
9
,10
tion of arenes.
Following the pioneering discovery of the
2
2
gold-catalyzed oxidative C(sp )−C(sp) cross-coupling be-
tween arenes and terminal alkynes to ethynylarenes,
C−H alkynylation of furans and various C−H arylations of
arenes with aryl silanes,
halides, aryl germanes, and other arenes to (hetero)-
biaryls have been reported. Additionally, the gold-catalyzed
oxi/amino-arylation of alkenes via the intramolecular cycliza-
tion and subsequent oxidative coupling of aryl boronic
10a
the
10b
Received: June 15, 2021
Published: July 28, 2021
1
0c,d
10e,f
aryl boronic acids,
aryl
1
0g
10h
10i
©
2021 American Chemical Society
https://doi.org/10.1021/acs.orglett.1c02007
5
891
Org. Lett. 2021, 23, 5891−5895

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pubs.acs.org/OrgLett
Letter
a
Scheme 1
Table 1. Optimization of the Reaction Conditions
b
yield (%)
entry
1
oxidant (equiv)
time (h)
1a
2a
3a
−
−
−
24
24
24
1.5
3
12
3
12
1.5
3
1.5
3
1.5
12
3
0
99
0
0
3
22
0
3
0
2
0
0
0
98
4
38
0
0
41
0
85
3
0
0
25
4
5
12
4
5
c
2
c,d
3
4
5
6
7
8
9
1
1
1
1
1
1
PIDA (1.2)
PIFA (1.2)
PhIO (1.2)
Selectfluor (1.2)
t-BuOOH (1.2)
PIDA (1.0)
PIDA (0.75)
PIDA (1.0)
PIDA (1.0)
PIDA (1.0)
PIDA (1.0)
PIDA (1.0)
75
57
55
32
39
73
62
86
87
75
0
0
1
2
3
4
5
e
e
e
e
e
,f
−
g
1
0
5
,
,
h
i
79
a
The reaction was carried out with 1a (0.1 mmol, 1 equiv), 1,3,5-
trimethoxybenzene (5 equiv), and AuCl (10 mol %) in CH Cl (0.4
3
2
2
b
c
M) at room temperature. Isolated yield. Ph PAuCl (10 mol %) was
3
d
e
used instead of AuCl . AgSbF (10 mol %) was added. In 0.1 M
3
6
f
g
CH Cl . AuCl (5 mol %) was used. 1,3,5-Trimethoxybenzene (2
2
2
3
h
i
equiv) was used. Without AuCl . With 1 mmol of 1a. See the
3
Supporting Information for a further detailed optimization.
efficiently underwent oxidative coupling to afford the
corresponding 2-(5-arylfuryl)methylbenzene derivatives (2b−
2f) in good yields. 1-Nonylpenta-3,4-dien-1-one (1g) also
reacted with 1,3,5-trimethoxybenzene to form the desired
product (2g). Furthermore, the reaction allowed the
construction of 2-furylmethylbenzenes (2h and 2i) containing
a trisubstituted furan ring. The oxidative C−H functionaliza-
tion of various (hetero)arene nucleophiles with β-ketoallene
(1a) proceeded to form the corresponding 2-furylmethylarenes
[benzylfurans and indolylmethylfurans (Scheme 2, bottom)].
1,3-Dimethoxybenzene, 2,6-dimethoxytoluene, 1-bromo-3,5-
dimethoxybenzene, and 3-methoxy-N,N-dimethylaniline com-
bined with 1a to form the corresponding products (2j−2m) in
moderate to high yields and with good regioselectivities. 5-
Methoxycarbazole was also applicable to the present reaction
as an arene nucleophile to afford the desired bisheteroaryl-
methane (2n). Simple indole and N-Me-, N-Ph-, or N-Bn-
indole derivatives smoothly coupled with 1a at position 3 of
the indole nucleus (2o−2r), and the yield of the reaction using
N-Me indole was higher. Therefore, the scope of the N-Me
indole derivative bearing the various substituents was
investigated to give the desired product (2s−2aa) without
the effect of electronic or steric influences based on various
substitutions. Notably, the aromatic halides (2u and 2v) and
boryl groups (2w), which can be transformed into various
functional groups, were tolerant under the reaction conditions
presented here. Meanwhile, reactions using 3-substituted
indoles provided 2-adducts (2ab and 2ac). These regiose-
lectivities are consistent with the properties of electrophilic
byproduct (entry 1). In contrast, Ph PAuCl and Ph PAuCl/
3
3
AgSbF as catalysts were ineffective for producing 2a (entries 2
6
and 3, respectively). The C−H functionalization of arene was
III
reported to be performed by the interaction with the Au
I
III
species. The generated Au needed to be oxidized to Au to
9
−11,14
promote the catalytic cycle (Scheme 3).
The addition of
PIDA, phenyliodine bistrifluoroacetate (PIFA), or iodosoben-
zene as a hypervalent iodine oxidant (1.2 equiv) improved the
yields of 2a (entry 1 vs entries 4−6), while Selectfluor and tert-
butyl hydroperoxide were ineffective as additives (entries 7 and
8
, respectively). Decreasing the PIDA load to 1.0 equiv was
also found to be effective (entry 9), and a further decrease in
the amount of PIDA to 0.75 equiv caused the slight increase in
the amount of 3a as a byproduct (entry 10). A lower
concentration of 1a (0.1 M in CH Cl ) improved the reaction
2
2
efficiency to afford 2a in 86% yield (entry 9 vs entry 11), and
decreasing the amount of AuCl added to 5 mol % maintained
3
the catalytic efficiency and afforded 87% 2a (entry 12). The
use of 2 equiv of 1,3,5-trimethoxybenzene also provided 2a in
7
5% yield (entry 13). The reaction without AuCl in the
3
presence of PIDA did not afford 2a, and 1a was quantitatively
recovered (entry 14). The scale-up reaction of 1a (1 mmol)
with 2a could be successfully performed to afford 2a in 79%
yield (entry 15).
The scope of β-ketoallenes [penta-3,4-dien-1-one (1)] with
,3,5-trimethoxybenzene was investigated next (Scheme 2,
1
top). Various 1-arylpenta-3,4-dien-1-one derivatives (1b−1f)
bearing electron-donating and electron-withdrawing groups at
the para, meta, or ortho position of each aromatic nucleus
15
aromatic substitution.
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Org. Lett. 2021, 23, 5891−5895

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pubs.acs.org/OrgLett
Letter
a
Scheme 2. Scope of Substrates
a
The reaction was carried out with 1a (0.1 mmol, 1 equiv), an arene nucleophile (5 equiv), PIDA (1 equiv), and AuCl (5 mol %) in CH Cl (0.1
3
2
2
b
M) at room temperature. AuCl (10 mol %) was used.
3
Scheme 3. Mechanistic Studies and Proposed Reaction Mechanism
a
The reaction was carried out with 1a (0.1 mmol, 1 equiv), 1,3,5-trimethoxybenzene (5 equiv), PIDA (1 equiv), and AuCl (5 mol %) in CH Cl
2
3
2
b
(
0.1 M) at room temperature. The reaction was carried out with 1,3,5-trimethoxybenzene (0.2 mmol), PIDA (0.1 mmol), and AuCl (0.1 mmol)
3
in CH Cl (0.1 M) at room temperature to give 5 (0.077 mmol).
2
2
The reaction of 1a with a combination of Ph PAuCl as a
one-valent gold catalyst and PIDA afforded 2a in 73% yield
Scheme 3A), while 1a was not converted to 2a without the
addition of PIDA (Table 1, entry 2). Moreover, 2-methyl-5-
optimized AuCl -catalyzed reaction conditions, and 89% of 3a
3
3
was recovered (Scheme 3B). Although electron-rich arenes
have been reported to react with PIDA to form a diary-
(
16
liodonium salt, the diaryliodonium salts (4) derived from
phenylfuran (3a) was not transformed to 2a under the
1,3,5-trimethoxybenzene and PIDA in the presence of AuCl3
5
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Org. Lett. 2021, 23, 5891−5895

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Letter
(
100 mol %) could not be detected during this reaction in the
General information, preparation of substrates, typical
procedures in gold-catalyzed 2-furylmethylarene syn-
thesis, optimization of gold-catalyzed 2-furylmethylarene
synthesis, spectroscopic data of the synthesized prod-
ucts, mechanistic studies and the proposed reaction
mechanism, kinetic isotope effect (KIE) experiments,
limitation of substrates, scale-up reaction, references, and
absence of 1a and 2,4,6-trimethoxychlorobenzene (5) was
obtained in 77% yield (Scheme 3C) However, during the key
reaction of β-ketoallene (1) and 1,3,5-trimethoxybenzene
presented here, 5 or 2-furylmethylarene derived from 5
could not be detected, which indicates that gold species
preferentially activated β-ketoallenes rather than arene
nucleophiles under the optimized reaction conditions. These
results also confirm that PIDA acts as an oxidant to convert the
1
13
H and C NMR spectra of the newly synthesized
substrates and products (PDF)
I
III
Au species to a Au species, thereby promoting the oxidative
coupling of β-ketoallenes and arenes. The addition of
AUTHOR INFORMATION
Corresponding Authors
■
deuterium oxide (D O) under the optimized conditions
2
without arene and PIDA provided a deuterium-incorporated
product (3a-d ) generated after deuterodeauration of the 2-
furylmethyl gold intermediate (A), which was formed by the
gold-catalyzed intramolecular 5-exocyclization of 1a (Scheme
Naoki Yasukawa − Laboratory of Organic Chemistry, Gifu
Pharmaceutical University, Gifu 501-1196, Japan; Present
Address: Department of Life Science and Applied
Chemistry, Graduate School of Engineering, Nagoya
Institute of Technology, Gokiso, Showa-ku, Nagoya 466-
8555, Japan; Email: yasukawa.naoki@nitech.ac.jp
Yoshinari Sawama − Laboratory of Organic Chemistry, Gifu
Pharmaceutical University, Gifu 501-1196, Japan; Present
Address: Graduate School of Pharmaceutical Sciences,
Osaka University, 1-6, Yamada-oka, Suita, Osaka 565-
0871, Japan.; orcid.org/0000-0002-9923-2412;
Email: sawama@phs.osaka-u.ac.jp
1
3
D). Because the reaction rates using nonlabeled and
17
deuterium-labeled 1,3,5-trimethoxybenzene were quite sim-
ilar [H/D kinetic isotope effect (KIE, k /k ) of 1.0] (Scheme
H
D
3
E), C−H functionalization of arene would not be the rate-
determining step.
The possible catalytic cycles based on these experiments are
18
shown in Scheme 3F. The β-ketoallene (1) is converted into
6
the enol intermediate (1′). Then, coordination of AuCl with
3
1
′ forms a gold−allene complex (I), which undergoes
intramolecular 5-exocyclization to form II, and the subsequent
III
Authors
olefin isomerization to afford a 2-furylmethyl Au intermediate
A). C(sp )−H auration of arene proceeds via electrophilic
aromatic substitution (S Ar) on the gold species to afford
complex III, and subsequent reductive elimination produces
together with the Au species. PIDA oxidizes the Au species
to regenerate the Au species (route A). Alternatively, in situ-
2
(
Yutaro Yamada − Laboratory of Organic Chemistry, Gifu
Pharmaceutical University, Gifu 501-1196, Japan
Chikara Furugen − Laboratory of Organic Chemistry, Gifu
Pharmaceutical University, Gifu 501-1196, Japan
Yuya Miki − Laboratory of Organic Chemistry, Gifu
Pharmaceutical University, Gifu 501-1196, Japan
Hironao Sajiki − Laboratory of Organic Chemistry, Gifu
Pharmaceutical University, Gifu 501-1196, Japan;
orcid.org/0000-0003-2792-6826
E
1
0
I
I
2
III
I
generated Au species can also coordinate with 1′ to form
gold−allene complex IV, and subsequent intramolecular 5-
I
exocycloisomerization produces Au intermediate V. Subse-
I
III
quent oxidation of Au intermediate V by PIDA affords Au
intermediate A in a manner similar to that shown in ref 18
route B). As the result of PIDA-mediated oxidation of
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.orglett.1c02007
(
I
Ph PAuCl as a Au species, iodobenzene as a reduced form of
3
PIDA was obtained in <10% yield (see the Supporting
Information). Therefore, route B might be the major route;
however, route A cannot be completely ruled out. In contrast,
Notes
The authors declare no competing financial interest.
the AuCl (10 mol %)-catalyzed reaction of 1 with 1,3,5-
3
ACKNOWLEDGMENTS
trimethoxybenzene in the absence of PIDA afforded 2 in 38%
yield (Table 1, entry 1). The reason is unclear (the proposed
reaction mechanism is described in the Supporting Informa-
tion).
In conclusion, we have developed an efficient synthesis of 2-
furylmethylarene derivatives via the gold-catalyzed oxidative
coupling of β-ketoallenes and arenes (benzene and indole
derivatives). Highly functionalized furan derivatives were
efficiently constructed in good to excellent yields in the
■
This study was partially supported by a Grant-in-Aid for JSPS
Research Fellows from the Japan Society for the Promotion of
Science (JSPS, 18J14010 for N.Y.), MEXT KAKENHI Grant
20H05738 (for Y.S.), and the Takeda Science Foundation (for
Y.S.). The authors appreciate Dr. Koji Morimoto in
Ritsumeikan University for the fruitful discussion. The authors
thank Editage (www.editage.com) for English language editing.
REFERENCES
presence of catalytic AuCl and PIDA at room temperature.
3
■
This novel synthetic method can be efficiently applied to
synthesize various furan-based biarylmethanes by choosing the
appropriate arene nucleophiles, such as electron-rich benzene,
indole, or carbazole nucleophiles.
(1) (a) Chiellini, G.; Nesi, G.; Sestito, S.; Chiarugi, S.; Runfola, M.;
Espinoza, S.; Sabatini, M.; Bellusci, L.; Laurino, A.; Cichero, E.;
Gainetdinov, R. R.; Fossa, P.; Raimondi, L.; Zucchi, R.; Rapposelli, S.
Hit-to-Lead Optimization of Mouse Trace Amine Associated
Receptor 1 (mTAAR1) Agonists with a Diphenylmethane-Scaffold:
Design, Synthesis, and Biological Study. J. Med. Chem. 2016, 59,
9825−9836. (b) Messaoudi, S.; Hamze, A.; Provot, O.; Treguier, B.;
Rodrigo De Losada, J.; Bignon, J.; Liu, J.-M.; Wdzieczak-Bakala, J.;
Thoret, S.; Dubois, J.; Brion, J.-D.; Alami, M. Discovery of Isoerianin
Analogues as Promising Anticancer Agents. ChemMedChem 2011, 6,
488−497.
ASSOCIATED CONTENT
■
*
sı Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.orglett.1c02007.
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(
2) (a) Shimizu, S.; Endo, T.; Izumi, K.; Mikamiyama, H.
Arylsilanes and Arenes: Origin of Selectivity and Improved
Precatalyst. J. Am. Chem. Soc. 2014, 136, 254−264. (e) Wu, Q.;
Du, C.; Huang, Y.; Liu, X.; Long, Z.; Song, F.; You, J. Stoichiometric
to catalytic reactivity of the aryl cycloaurated species with arylboronic
Development of HIV-Integrase Inhibitor S-1360: Selection of the
Protecting Group on the 1,2,4-Triazole Ring. Org. Process Res. Dev.
2
007, 11, 1055−1058. (b) Sun, Y.; Tabata, K.; Matsubara, H.;
2
Kitanaka, S.; Suzuki, T.; Yasukawa, K. New Cytotoxic Diary-
acids: insight into the mechanism of gold-catalyzed oxidative C(sp )−
lheptanoids from the Rhizomes of Alpinia officinarum. Planta Med.
H arylation. Chem. Sci. 2015, 6, 288−293. (f) Hofer, M.; Genoux, A.;
Kumar, R.; Nevado, C. Gold-Catalyzed Direct Oxidative Arylation
with Boron Coupling Partners. Angew. Chem., Int. Ed. 2017, 56,
1021−1025. (g) Zeineddine, A.; Estévez, L.; Mallet-Ladeira, S.;
Miqueu, K.; Amgoune, A.; Bourissou, D. Rational development of
catalytic Au(I)/Au(III) arylation involving mild oxidative addition of
aryl halides. Nat. Commun. 2017, 8, 565. (h) Fricke, C.; Dahiya, A.;
Reid, W. B.; Schoenebeck, F. Gold-Catalyzed C−H Functionalization
with Aryl Germanes. ACS Catal. 2019, 9, 9231−9236. (i) Cambeiro,
X. C.; Ahlsten, N.; Larrosa, I. Au-Catalyzed Cross-Coupling of Arenes
via Double C−H Activation. J. Am. Chem. Soc. 2015, 137, 15636−
15639.
2
008, 74, 427−431. (c) Yoo, G.; Ahn, S.; Joe, T.; Kim, J.; Lee, D.-C.
Inhibitory Effects of 1-(5-Benzyl-4-(4-chlorophenyl)-2-methylfuran-3-
yl)ethan-1-one on Allergic Inflammatory Responses in Rat Basophilic
Leukemia Cells. Bull. Korean Chem. Soc. 2015, 36, 2166−2169.
(
d) Frias, M.; Padron, J. M.; Aleman, J. Dienamine and Friedel-Crafts
One-Pot Synthesis, and Antitumor Evaluation of Diheteroarylalkanals.
Chem. - Eur. J. 2015, 21, 8237−8241.
(
Suzuki−Miyaura coupling, see: (a) Kuriyama, M.; Shinozawa, M.;
Hamaguchi, N.; Matsuo, S.; Onomura, O. Palladium-Catalyzed
Synthesis of Heterocycle-Containing Diarylmethanes through Suzu-
ki−Miyaura Cross-Coupling. J. Org. Chem. 2014, 79, 5921−5928.
3) For selected examples of 2-furylmethylarene synthesis based on
(11) (a) Zhang, G.; Cui, L.; Wang, Y.; Zhang, L. Homogeneous
Gold-Catalyzed Oxidative Carboheterofunctionalization of Alkenes. J.
Am. Chem. Soc. 2010, 132, 1474−1475. (b) Brenzovich, W. E., Jr.;
Benitez, D.; Lackner, A. D.; Shunatona, H. P.; Tkatchouk, E.;
Goddard, W. A., III; Toste, F. D. Gold-Catalyzed Intramolecular
Aminoarylation of Alkenes: C-C Bond Formation through Bimo-
lecular Reductive Elimination. Angew. Chem., Int. Ed. 2010, 49, 5519−
(
b) Ohsumi, M.; Ito, A.; Nishiwaki, N. Substrate switchable Suzuki−
Miyaura coupling for benzyl ester vs. benzyl halide. RSC Adv. 2018, 8,
5056−35061.
4) For selected examples of 2-furylmethylarene synthesis based on
3
(
Friedel−Crafts reaction, see: (a) Wu, H.-J.; Lin, C.-C. First Exclusive
Regioselective Fragmentation of Primary Ozonides Controlled by
Remote Carbonyl Groups and a New Method for Determining the
Regiochemistry of Carbonyl Oxide Formation. J. Org. Chem. 1996, 61,
5
522. (c) Tkatchouk, E.; Mankad, N. P.; Benitez, D.; Goddard, W. A.,
III; Toste, F. D. Two Metals Are Better Than One in the Gold
Catalyzed Oxidative Heteroarylation of Alkenes. J. Am. Chem. Soc.
3820−3828. (b) Asao, N.; Aikawa, H.; Tago, S.; Umetsu, K. Gold-
2
011, 133, 14293−14300. (d) Ball, L. T.; Green, M.; Lloyd-Jones, G.
Catalyzed Etherification and Friedel−Crafts Alkylation Using ortho-
Alkynylbenzoic Acid Alkyl Ester as an Efficient Alkylating Agent. Org.
Lett. 2007, 9, 4299−4302.
C.; Russell, C. A. Arylsilanes: Application to Gold-Catalyzed
Oxyarylation of Alkenes. Org. Lett. 2010, 12, 4724−4727.
(12) (a) Sahoo, B.; Hopkinson, M. N.; Glorius, F. Combining Gold
(
5) Reviews: (a) Hashmi, A. S. K. Gold-Catalyzed Organic
and Photoredox Catalysis: Visible Light-Mediated Oxy- and Amino-
arylation of Alkenes. J. Am. Chem. Soc. 2013, 135, 5505−5508.
Reactions. Chem. Rev. 2007, 107, 3180−3211. (b) Gorin, D. J.;
Sherry, B. D.; Toste, F. D. Ligand Effects in Homogeneous Au
Catalysis. Chem. Rev. 2008, 108, 3351−3378. (c) Li, Z. G.; Brouwer,
C.; He, C. Gold-Catalyzed Organic Transformations. Chem. Rev.
(
b) Hopkinson, M. N.; Tlahuext-Aca, A.; Glorius, F. Merging Visible
Light Photoredox and Gold Catalysis. Acc. Chem. Res. 2016, 49,
261−2272.
13) Rigoulet, M.; Thillaye du Boullay, O.; Amgoune, A.; Bourissou,
2
2
008, 108, 3239−3265. (d) Krause, N.; Winter, C. Gold-Catalyzed
(
Nucleophilic Cyclization of Functionalized Allenes: A Powerful
D. Gold(I)/Gold(III) Catalysis that Merges Oxidative Addition and
Access to Carbo- and Heterocycles. Chem. Rev. 2011, 111, 1994−
π-Alkene Activation. Angew. Chem., Int. Ed. 2020, 59, 16625−16630.
2
(
009.
(14) (a) Iglesias, A.; Muniz, K. Oxidative Interception of the
6) Hosseyni, S.; Su, Y.; Shi, X. Gold Catalyzed Synthesis of
Hydroamination Pathway: A Gold-Catalyzed Diamination of Alkenes.
Chem. - Eur. J. 2009, 15, 10563−10569. (b) Wegner, H. A.; Ahles, S.;
Neuburger, M. A New Gold-Catalyzed Domino Cyclization and
Oxidative Coupling Reaction. Chem. - Eur. J. 2008, 14, 11310−11313.
Substituted Furan by Intermolecular Cascade Reaction of Propargyl
Alcohol and Alkyne. Org. Lett. 2015, 17, 6010−6013.
(7) Ji, K.-G.; Shu, X.-Z.; Chen, J.; Zhao, S.-C.; Zheng, Z.-J.; Liu, X.-
Y.; Liang, Y.-M. Gold-catalyzed tandem cyclization/Friedel−Crafts
type reactions toward furan derivatives. Org. Biomol. Chem. 2009, 7,
(15) (a) Jackson, A. H.; Lynch, P. P. Electrophilic substitution in
indoles. Part 12. Kinetic studies of the rearrangement of 3,3-
disubstituted indolenines to 2,3-disubstituted indoles. J. Chem. Soc.,
Perkin Trans. 2 1987, 1215−1219. (b) Rodriguez, J.; Zeineddine, A.;
Sosa Carrizo, E. D.; Miqueu, K.; Saffon-Merceron, N.; Amgoune, A.;
Bourissou, D. Catalytic Au(i)/Au(iii) arylation with the hemilabile
MeDalphos ligand: unusual selectivity for electron-rich iodoarenes
and efficient application to indoles. Chem. Sci. 2019, 10, 7183−7192.
2
(
501−2505.
8) Kulandai Raj, A. S.; Narode, A. S.; Liu, R.-S. Gold(I)-Catalyzed
Reactions between N-(o-Alkynylphenyl)imines and Vinyldiazo
Ketones to Form 3-(Furan-2-ylmethyl)-1H-indoles via Postulated
Azallyl Gold and Allylic Cation Intermediates. Org. Lett. 2021, 23,
1
(
378−1382.
9) Reviews: (a) Wegner, H. A.; Auzias, M. Gold for C−C Coupling
Reactions: A Swiss-Army-Knife Catalyst? Angew. Chem., Int. Ed. 2011,
0, 8236−8247. (b) Hopkinson, M. N.; Gee, A. D.; Gouverneur, V.
(16) Seidl, T. L.; Sundalam, S. K.; McCullough, B.; Stuart, D. R.
Unsymmetrical Aryl(2,4,6-trimethoxyphenyl)iodonium Salts: One-
Pot Synthesis, Scope, Stability, and Synthetic Studies. J. Org. Chem.
5
AuI/AuIII Catalysis: An Alternative Approach for C−C Oxidative
Coupling. Chem. - Eur. J. 2011, 17, 8248−8262. (c) Nijamudheen, A.;
Datta, A. Gold-Catalyzed Cross-Coupling Reactions: An Overview of
Design Strategies, Mechanistic Studies, and Applications. Chem. - Eur.
J. 2020, 26, 1442−1487. (d) Fricke, C.; Reid, W. B.; Schoenebeck, F.
A Review on Oxidative Gold-Catalyzed C-H Arylation of Arenes -
Challenges and Opportunities. Eur. J. Org. Chem. 2020, 2020, 7119−
2
(
016, 81, 1998−2009.
17) Deuterium-labeled 1,3,5-trimethoxybenzene was prepared by
the Ir/C-catalyzed hydrogen (H)−deuterium (D) exchange deutera-
tion of aromatic nuclei in 2-PrOH and D O according to the
2
following: Sawama, Y.; Nakano, A.; Matsuda, T.; Kawajiri, T.;
Yamada, T.; Sajiki, H. H−D. Exchange Deuteration of Arenes at
Room Temperature. Org. Process Res. Dev. 2019, 23, 648−653.
detailed procedure is shown in the Supporting Information.
A
7
(
130.
10) (a) de Haro, T.; Nevado, C. Gold-Catalyzed Ethynylation of
(18) Hofer, M.; de Haro, T.; Gómez-Bengoa, E.; Genoux, A.;
Arenes. J. Am. Chem. Soc. 2010, 132, 1512−1513. (b) Li, Y.; Brand, J.
P.; Waser, J. Gold-Catalyzed Regioselective Synthesis of 2- and 3-
Alkynyl Furans. Angew. Chem., Int. Ed. 2013, 52, 6743−6747. (c) Ball,
L. T.; Lloyd-Jones, G. C.; Russell, C. A. Gold-Catalyzed Direct
Arylation. Science 2012, 337, 1644−1648. (d) Ball, L. T.; Lloyd-Jones,
G. C.; Russell, C. A. Gold-Catalyzed Oxidative Coupling of
Nevado, C. Oxidant speciation and anionic ligand effects in the gold-
catalyzed oxidative coupling of arenes and alkynes. Chem. Sci. 2019,
10, 8411−8420.
5
895
https://doi.org/10.1021/acs.orglett.1c02007
Org. Lett. 2021, 23, 5891−5895