Decarboxylative Oxyacyloxylation of Propiolic Acids: Construction of Alkynyl-Containing α-Acyloxy Ketones

Article abstract of DOI:10.1021/acs.joc.1c00669

Novel decarboxylative oxyacyloxylation of propiolic acids has been developed. This reaction provides an efficient access to alkynyl-containing α-acyloxy ketones from readily available starting materials and exhibits significant functional group tolerance. Furthermore, oxyacyloxylation of terminal alkynes and aliphatic propiolic acids was also developed. A possible reaction mechanism is proposed based on mechanistic studies.

Full text of DOI:10.1021/acs.joc.1c00669

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Article
Decarboxylative Oxyacyloxylation of Propiolic Acids: Construction
of Alkynyl-Containing α‑Acyloxy Ketones
Xin Chen, Yangchun Xin, Zhi-Wei Zhao, Yu-Jian Hou, Xiang-Xiang Wang, Wen-Jin Xia, and Ya-Min Li*
Cite This: J. Org. Chem. 2021, 86, 8216−8225
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ABSTRACT: Novel decarboxylative oxyacyloxylation of propiolic
acids has been developed. This reaction provides an efficient access to
alkynyl-containing α-acyloxy ketones from readily available starting
materials and exhibits significant functional group tolerance.
Furthermore, oxyacyloxylation of terminal alkynes and aliphatic
propiolic acids was also developed. A possible reaction mechanism
is proposed based on mechanistic studies.
Scheme 1. Constructing α-Substituted Ketones via the
Decarboxylative Difunctionalization of Propiolic Acids
INTRODUCTION
■
α-Acyloxy ketone motifs widely exist in many natural products,
synthetic drugs, and bioactive molecules.1 They also serve as
versatile intermediates in organic synthesis, and widespread
synthetic applications of α-acyloxy ketones in the construction
of hydroxy ketones, diol derivatives, allylic esters, amino
acyloxy compounds, heterocyclic aromatic scaffolds, and others
have been demonstrated.2 In light of their importance,
numerous methods for the synthesis of α-acyloxy ketones
including the acetolysis of α-haloketones, insertion of α-
diazoketones with carboxylic acids, direct oxidative coupling of
ketones, and difunctionalization of alkenes or alkynes have
been developed.3,4 Despite these advances, developing an
efficient method for the construction of α-acyloxy ketones is
still in need.
Decarboxylative coupling is a powerful strategy for the C−C
and C− heteroatom bond construction as such reactions
feature the utilization of readily available and stable carboxylic
acids, less-toxic carbon dioxide as the byproduct, and high
selectivity.5 Because the first example was reported by Lee and
co-workers, who developed a decarboxylative coupling reaction
of aryl halides with propiolic acids using a palladium catalytic
system to form unsymmetric diarylalkynes,6 decarboxylative
coupling of propiolic acids has drawn much attention,7 and
many reactions have been explored for C−C,8 C−N,9 C−B,10
C−P,11 C−S,12 C−Se,13 and C−Si14 bond formation. In this
context, great efforts have been devoted to construct α-
substituted ketones by the decarboxylative difunctionalization
of propiolic acids.15 Hu et al. reported the copper-mediated
decarboxylative oxytrifluoromethylation of propiolic acids with
Togni’s agent to form α-trifluoromethyl ketones (Scheme
1a).15a Zhao and Song independently described the synthesis
of β-ketophosphine oxides and β-ketophosphonates through
copper-catalyzed decarboxylative oxyphosphinations (Scheme
1b).15b,c Copper- and manganese-promoted decarboxylative
oxysulfonylations were also achieved to produce β-ketosulfones
(Scheme 1c).15d,e Feng, Xu, and co-workers reported copper-
catalyzed oxytrifluoromethylthiolation for the synthesis of
trifluoromethylthiolated ketones (Scheme 1d).15f Recently,
copper-catalyzed oxyalkylation of propiolic acids with ketones
and alkylnitriles was also developed to construct γ-diketones
and γ-ketonitriles by our group (Scheme 1e).15g However, to
the best of our knowledge, the decarboxylative oxyacylox-
ylation of propiolic acids remains underexplored until now.
With our growing interest in decarboxylative coupling,15g,16 we
herein present novel decarboxylative oxyacyloxylation of
Received: March 21, 2021
Published: June 4, 2021
https://doi.org/10.1021/acs.joc.1c00669
© 2021 American Chemical Society
J. Org. Chem. 2021, 86, 8216−8225
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a
Table 1. Optimization of the Reaction Conditions
b
c
entry
metal salt (mol %)
PhI(OAc)2 (equiv)
base (equiv)
solvent (v/v)
temp (°C)
yield (%)
2a/3a
1
2
3
4
5
6
7
8
Cu(OAc)2 (10)
Cu(acac)2 (10)
CuCl2 (10)
3
3
3
3
3
3
3
3
3
3
3
3
3
2
2
2
2
2
0
2
2
2
2
DME/H2O (1/2)
DME/H2O (1/2)
DME/H2O (1/2)
DME/H2O (1/2)
DME/H2O (1/2)
DME/H2O (1/2)
DME/H2O (1/2)
DME/H2O (1/2)
DME/H2O (1/2)
DME/H2O (1/2)
CH3CN/H2O (1/2)
PhCl/H2O (1/2)
toluene/H2O (1/2)
toluene/H2O (1/2)
toluene/H2O (3/1)
toluene/H2O (3/1)
toluene/H2O (3/1)
toluene/H2O (3/1)
toluene/H2O (3/1)
toluene/H2O (3/1)
toluene/H2O (3/1)
toluene/H2O (3/1)
toluene/H2O (3/1)
80
80
80
80
80
80
80
80
80
80
80
80
80
80
80
80
70
70
70
70
70
70
70
34
37
22
39
42
37
44
30
33
30
18
56
61
68
71
75
77
79
0
2.9/1
5.2/1
2.7/1
6.6/1
3.4/1
1.7/1
1.5/1
1.3/1
1.4/1
1.4/1
1.2/1
1.8/1
3.4/1
5.4/1
3.3/1
4.7/1
3.7/1
5.6/1
copper quinolate (10)
copper quinolate (5)
copper quinolate (5)
copper quinolate (5)
copper quinolate (5)
copper quinolate (5)
copper quinolate (5)
copper quinolate (5)
copper quinolate (5)
copper quinolate (5)
copper quinolate (5)
copper quinolate (5)
copper quinolate (7.5)
copper quinolate (7.5)
copper quinolate (7.5)
copper quinolate (7.5)
copper quinolate (7.5)
copper quinolate (7.5)
NaHCO3(1)
KHCO3 (1)
t-BuONa (1)
K2CO3
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Et3N
KHCO3 (1)
KHCO3 (1)
KHCO3 (1)
KHCO3 (1)
KHCO3 (1)
KHCO3 (1)
KHCO3 (1)
KHCO3 (1)
KHCO3 (1)
KHCO3 (1)
KHCO3 (1)
KHCO3 (1)
KHCO3 (1)
d
d
de
,
13
46
65
df
,
d
3.2/1
3.7/1
dg
,
copper quinolate (7.5)
74
a
b
Reaction conditions: 1a (0.6 mmol), PhI(OAc)2, metal salt, and base in the solvent (6 mL) at 80 °C for 12 h under air. Isolated yield of 2a.
c
d
e
1
Ratio was determined by H NMR of the crude products. The reaction was carried out for 6 h. PhI(OAc)2 was replaced by PhI(TFA)2.
f
g
PhI(OAc)2 was replaced by PhI(OH)OTs. The reaction was carried out under an Ar atmosphere.
propiolic acids to synthesize alkynyl-containing α-acyloxy
ketones (Scheme 1f).
2a was increased to 77% when performing the reaction at 70
°C (Table 1, entry 17) and further improved to 79% when this
transformation was carried out for 6 h (Table 1, entry 18).
PhI(OAc)2 was important for the reaction, and this
decarboxylative oxyacyloxylation could not take place without
PhI(OAc)2 (Table 1, entry 19). When PhI(OAc)2 was
replaced by PhI(TFA)2 and PhI(OH)OTs, lower yields were
obtained (Table 1, entries 20 and 21). The control experiment
showed that 2a could be isolated in 65% yield in the absence of
copper quinolate, which illustrates that copper salt acts as a
promoter rather than a catalyst in this oxyacyloxylation (Table
1, entry 22). The atmosphere exhibited no effect on the
reaction, and 74% of 2a was obtained when this reaction was
performed under an Ar atmosphere (Table 1, entry 23).
The scope of the oxyacyloxylation of propiolic acids was
investigated under the optimized conditions (Table 1, entry
21), and the results are summarized in Table 2. Both electron-
rich and electron-poor phenylpropiolic acids underwent
smooth conversion when alkyl, halide, trifluoromethoxy,
aldehyde, ketone, cyano, nitro, ester, and trifluoromethyl
groups were present as substituents in the benzene ring,
providing the corresponding α-acyloxy ketones 2a−w in
moderate to good yields. Steric hindrance in ortho-substituted
phenylpropiolic acid has a significant influence on decarbox-
ylative oxyacyloxylation, resulting in moderate yields in all the
cases (2 s−2w). Dimethyl-substituted phenylpropiolic acid was
compatible with the optimized conditions, and the product 2x
was obtained in 56% yield. Naphthyl propiolic acid and
thienylpropiolic acid were also compatible with this system,
RESULTS AND DISCUSSION
■
We initially chose phenylpropiolic acid 1a as the model
substrate for the survey of reaction conditions. When 1a was
treated with 10 mol % of Cu(OAc)2 and 3.0 equiv of
PhI(OAc)2 in DME/H2O at 80 °C, to our delight, the desired
alkynyl-containing α-acyloxy ketone 2a was obtained in 34%
yield, along with α-acetoxy acetophenone 3a as a byproduct
(Table 1, entry 1). Several copper salts, such as Cu(acac)2,
CuCl2, and copper quinolate were tested, and copper quinolate
was found to be more efficient than others (Table 1, entries 2−
4). Using 5 mol % of copper quinolate resulted in a slightly
higher yield (Table 1, entry 5). When KHCO3 was employed
as a base, the yield of 2a improved to 44%, while the addition
of other bases, NaHCO3, NaOAc, t-BuONa, K2CO3, and Et3N,
did not allow further improvements (Table 1, entries 6−10).
Different solvents were screened, and the results indicated that
toluene/H2O was the most efficient solvent for this reaction
(Table 1, entries 11−13). The amount of PhI(OAc)2 also
exhibited an effect on the yields of decarboxylative oxy-
acyloxylation. When the amount of PhI(OAc)2 was decreased
from 3 equiv to 2 equiv, the yield of 2a increased from 61 to
68% (Table 1, entry 14). The effect of the volume ratios of
toluene to H2O was investigated, and it was found that the
appropriate ratio was 3/1 (Table 1, entry 15). Reoptimizing
the amount of copper salt revealed that 7.5 mol % of copper
quinolate is the best choice (Table 1, entry 16). The yield of
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a b c d
, , ,
isolated. We further investigated the reaction of phenyl-
propiolic acid with benzoic acid, and a series of reaction
conditions including the ratio of substrates, the amount of
PhI(OAc)2, and others were screened for delivering the cross-
coupling product, 2-oxo-2-phenylethyl benzoate. However, the
self-coupling of phenylpropiolic acid was still dominant to form
2a (see the Supporting Information).
Table 2. Substrate Scope
A gram-scale reaction was carried out to demonstrate the
potential applications of this decarboxylative oxyacyloxylation.
When 13.2 mmol of phenylpropiolic acid 1a was employed as
the reactant, 1.38 g of the product 2a was obtained in 79%
yield, which revealed that the transformation could be readily
scaled up without loss of activity (Scheme 3).
Scheme 3. Gram-Scale Synthesis
Although alkylpropiolic acids were of low reactivity and the
reaction of two different propiolic acids provided mixed α-
acyloxy ketones, it was found that α-acyloxy ketone containing
aliphatic alkynyl group (5a) could be obtained in 62% yield
when phenylacetylene was treated with but-2-ynoic acid in the
presence of 7.5 mol % of copper quinolate and 4.0 equiv of
PhI(OAc)2 in toluene/H2O [3/1 (v/v)] at 70 °C for 12 h. The
scope of the oxyacyloxylation of terminal alkynes and aliphatic
propiolic acids was also examined. As shown in Table 3, aside
from but-2-ynoic acid, other aliphatic propiolic acids such as
pent-2-ynoic acid, hex-2-ynoic acid, 4,4-dimethylpent-2-ynoic
acid, and propiolic acid were also suitable substrates, giving α-
acyloxy ketones in moderate yields (5b−5e). With respect to
the alkynes employed, phenylacetylenes bearing electron-
donating or electron-withdrawing groups, including alkyl,
halides, nitrile, and trimethylsilanyl groups, could be trans-
ferred to corresponding products 5f−5l in moderate yields.
Naphthylacetylene showed good efficiency, affording 5m in
57% yields. Aliphatic hex-1-yne was also compatible with this
system, albeit in low yield (5n). This oxyacyloxylation is not
limited to propiolic acids, and the reactions of phenylacetylene
with trans-cinnamic acid and cyclobutanecarboxylic acid
provided 5o and 5p in 36 and 21% yields, respectively.
To gain insights into the mechanism of decarboxylative
oxyacyloxylation, several control experiments were performed
(Scheme 4). Initially, the reaction of slightly excess phenyl-
acetylene 4a with 3-(3-bromophenyl)propiolic acid 1n was
carried out in the absence of copper quinolate; cross-coupling
product 6 was obtained in 22% yield, along with 65% of self-
coupling product 2n (Scheme 4a). When (phenylethynyl)
copper 7 was treated with 3-(3-bromophenyl)propiolic acid 1n
without copper salt, no phenyl ketone 6 was observed, while 3-
bromophenyl ketone 2n was isolated in 18% yield (Scheme
4b). Only trace amounts of α-acetoxy acetophenone 3a were
detected when (phenylethynyl)copper was employed as the
substrate (Scheme 4c). The reaction of α-acetoxy acetophe-
none 3a with propiolic acid 1m was also carried out under the
optimized reaction conditions, and no phenyl ketone 8 was
observed (Scheme 4d). These results indicate that decarbox-
ylation might not be the rate-determining step, and alkynyl
copper and α-acetoxy acetophenone should not be inter-
mediates in this transformation. Furthermore, the Ar
a
Reaction conditions: 1 (0.6 mmol), PhI(OAc)2 (2.0 equiv), copper
quinolate (7.5 mol %), and KHCO3 (1.0 equiv) in 6 mL of toluene/
H2O [3/1 (v/v)] at 70 °C for 6 h under air. Isolated yield. The
reaction was carried out at 80 °C. Reaction conditions: 1aa (0.6
mmol), PhI(OAc)2 (3.0 equiv), copper quinolate (7.5 mol %), and
KHCO3 (1.0 equiv) in 6 mL of toluene/H2O [3/1 (v/v)] at 70 °C for
12 h under air.
b
c
d
giving the desired α-acyloxy ketones 2y and 2z in 20 and 48%
yield, respectively. Aside from arylpropiolic acids, alkenyl
propiolic acid was a suitable substrate for transformation, albeit
in low yield (2aa). However, no product 2bb was observed
when alkylpropiolic acid and oct-2-ynoic acid were subjected
to the reaction conditions probably because of low reactivity.
The reaction of two different propiolic acids was also
investigated. As shown in Scheme 2, when 3-(2-chlorophenyl)-
propiolic acid 1u was treated with 3-(3-(methoxycarbonyl)-
phenyl)propiolic acid 1r under the optimal reaction con-
ditions, four α-acyloxy ketones, 2cc, 2u, 2dd and 2r, were
Scheme 2. Decarboxylative Oxyacyloxylation of Two
Different Propiolic Acids
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Table 3. Substrate Scope of Terminal Alkynes and
Carboxylic Acids
Scheme 4. Mechanistic Studies
a b c
, ,
a
Reaction conditions: 1 (0.6 mmol), 4 (2.0 equiv), PhI(OAc)2 (4.0
equiv), copper quinolate (7.5 mol %), and KHCO3 (1.0 equiv) in 6
Scheme 5. Proposed Mechanism
b
mL of toluene/H2O [3/1 (v/v)] at 70 °C for 12 h under air. Isolated
c
yield. Reaction conditions: 1 (0.6 mmol), 4 (4.0 equiv), PhI(OAc)2
(4.0 equiv), copper quinolate (7.5 mol %), and KHCO3 (1.0 equiv) in
6 mL of toluene/H2O [3/1 (v/v)] at 70 °C for 12 h under air.
atmosphere had no effect on the reaction, implying that the
oxygen atom in the newly formed carbonyl group might not
originate from O2. In order to determine the oxygen source,
the isotopic-labeling experiments were conducted. When the
reaction of 1a was performed under an 18O2 atmosphere, no
18O-labeled product was detected (Scheme 4e). However,
when H216O was replaced by H218O, the 18O-labeled products
were observed (2a-16O3/2a-18O16O2/2a-18O216O/2a-18O3
=
10/67/20/3), and 18O-labeling of ketone carbonyl oxygen was
dominant, indicating that H218O might be the oxygen source
(Scheme 4f and the Supporting Information). Finally, the
reaction of 3-(3-(methoxycarbonyl)phenyl)propiolic acid was
monitored by the mass spectrometry experiment, and the
signal at m/z 380.9954, which was consistent with the mass of
[C′ + H]+, was observed (Scheme 5). This result provides
support for this transformation possibly involving the
intermediate iodonium ylide.
iodonium group of intermediate D is substituted by propiolic
acid to form alkynyl-containing α-acyloxy ketone. Copper salt
probably acts as a Lewis acid to coordinate with the C−C
triple bonds of alkyne to help the attack by H2O.
Although a detailed mechanism is still not clear, a plausible
mechanism for the decarboxylative oxyacyloxylation of
propiolic acids is proposed based on the literature4f,17 and
above experimental results (Scheme 5). Initially, propiolic acid
1 undergoes the reaction with PhI(OAc)2 to generate
alkynyliodonium salt intermediate A, followed by an addition
with H2O leading to intermediate B. Subsequently, the
elimination of acetate anions and keto−enol tautomerism of
intermediate B provides iodonium ylide C, which is further
converted to alkyliodonium salt D. Finally, the phenyl-
CONCLUSIONS
■
In summary, novel, efficient, and practical decarboxylative
oxyacyloxylation of propiolic acids has been successfully
developed. This transformation features good compatibility
with different types of substituents and the use of readily
available and stable reagents, thus providing convenient access
to alkynyl-containing α-acyloxy ketones. In addition, the
oxyacyloxylation of alkynes and aliphatic propiolic acids was
also developed.
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acid (42 mg, 0.60 mmol, 1.0 equiv) and toluene (4.5 mL) was added
slowly to the stirring mixture. The reaction mixture was allowed to stir
at 70 °C (oil bath temperature) under air for 12 h. After cooling to
room temperature, 4 mL of saturated NaHCO3 solution was added
and extracted with ethyl acetate. The organic phase was dried over
anhydrous Na2SO4 and filtered. The filtrate was concentrated by
rotary evaporation and purified by flash chromatography on silica gel
with petroleum ether/dichloromethane as the eluent to afford the
corresponding product 5e.
Typical Procedure for the Synthesis of α-Acyloxy Ketones
5o. Terminal alkyne 4a (245 mg, 2.4 mmol, 2.0 equiv), PhI(OAc)2
(773 mg, 2.4 mmol, 4.0 equiv), copper quinolate (15.9 mg, 0.045
mmol, 7.5 mol %), KHCO3 (60 mg, 0.6 mmol, 1.0 equiv), cinnamic
acid (73 mg, 0.6 mmol, 1.0 equiv), toluene (4.5 mL), and H2O (1.5
mL) were added in a sealed tube with a Teflon-lined cap. The mixture
was allowed to stir at 70 °C (oil bath temperature) under air for 12 h.
After cooling to room temperature, 4 mL of saturated NaHCO3
solution was added and extracted with ethyl acetate. The organic
phase was dried over anhydrous Na2SO4 and filtered. The filtrate was
concentrated by rotary evaporation and purified by flash chromatog-
raphy on silica gel with petroleum ether/dichloromethane as the
eluent to afford the corresponding product 5o.
EXPERIMENTAL SECTION
■
General Information. Propiolic acids 1a, 1bb, and all terminal
alkynes 4 were obtained from commercial sources. Propiolic acids18
1b−1n, 1p, 1r−1v, 1y, 1z, 1aa, and (phenylethynyl)copper19 were
prepared following literature procedures. Flash chromatography was
1
carried out on silica gel (200−300 mesh). NMR (600 MHz for H;
151 MHz for 13C) spectra were recorded in CDCl3. Chemical shifts
(δ) and coupling constants (J) are reported in ppm and Hz,
respectively, using TMS as the internal standard. High-resolution
mass spectra (HRMS) were measured on Agilent 6530 Accurate-Mass
Q-TOF LC/MS and Thermo LTQ Orbitrap XL spectrometers by
electrospray ionization (ESI).
General Procedure for the Synthesis of α-Acyloxy Ketones
2a−2y and 2bb. Propiolic acid 1 (0.60 mmol, 1.0 equiv),
PhI(OAc)2 (386 mg, 1.2 mmol, 2.0 equiv), copper quinolate (15.9
mg, 0.045 mmol, 0.075 equiv), KHCO3 (60 mg, 0.6 mmol, 1.0 equiv),
toluene (4.5 mL), and H2O (1.5 mL) were added in a sealed tube
with a Teflon-lined cap. The mixture was allowed to stir at 70 °C (oil
bath temperature) under air for 6 h. After cooling to room
temperature, 4 mL of saturated NaHCO3 solution was added and
extracted with ethyl acetate. The organic phase was dried over
anhydrous Na2SO4 and filtered. The filtrate was concentrated by
rotary evaporation and purified by flash chromatography on silica gel
with petroleum ether/ethyl acetate as the eluent to afford the
corresponding product.
Typical Procedure for the Synthesis of α-Acyloxy Ketone
2z. 3-(Thiophen-3-yl)propiolic acid (91 mg, 0.60 mmol, 1.0 equiv),
PhI(OAc)2 (386 mg, 1.2 mmol, 2.0 equiv), copper quinolate (15.9
mg, 0.045 mmol, 0.075 equiv), KHCO3 (60 mg, 0.6 mmol, 1.0 equiv),
toluene (4.5 mL), and H2O (1.5 mL) were added in a sealed tube
with a Teflon-lined cap. The mixture was allowed to stir at 80 °C (oil
bath temperature) under air for 6 h. After cooling to room
temperature, 4 mL of saturated NaHCO3 solution was added and
extracted with ethyl acetate. The organic phase was dried over
anhydrous Na2SO4 and filtered. The filtrate was concentrated by
rotary evaporation and purified by flash chromatography on silica gel
with petroleum ether/ethyl acetate as the eluent to afford the
corresponding product 2z.
Typical Procedure for the Synthesis of α-Acyloxy Ketone
2aa. 3-(Cyclohex-1-en-1-yl)propiolic acid (90 mg, 0.60 mmol, 1.0
equiv), PhI(OAc)2 (580 mg, 1.8 mmol, 3.0 equiv), copper quinolate
(15.9 mg, 0.045 mmol, 0.075 equiv), KHCO3 (60 mg, 0.6 mmol, 1.0
equiv), toluene (4.5 mL), and H2O (1.5 mL) were added in a sealed
tube with a Teflon-lined cap. The mixture was allowed to stir at 70 °C
(oil bath temperature) under air for 12 h. After cooling to room
temperature, 4 mL of saturated NaHCO3 solution was added and
extracted with ethyl acetate. The organic phase was dried over
anhydrous Na2SO4 and filtered. The filtrate was concentrated by
rotary evaporation and purified by flash chromatography on silica gel
with petroleum ether/ethyl acetate as the eluent to afford the
corresponding product 2aa.
2-Oxo-2-phenylethyl 3-phenylpropiolate (2a). Purification was
performed by column chromatography (petroleum ether/ethyl acetate
= 30/1) to afford 63 mg (79%) of 2a. White solid, mp 86−87 °C. 1H
NMR (600 MHz, CDCl3) δ 7.97−7.91 (m, 2H), 7.67−7.59 (m, 3H),
7.51 (t, J = 7.8 Hz, 2H), 7.49−7.45 (m, 1H), 7.40 (t, J = 7.6 Hz, 2H),
5.50 (s, 2H). 13C{1H} NMR (151 MHz, CDCl3) δ 190.9, 153.3,
134.1, 133.9, 133.1, 130.9, 128.9, 128.6, 127.8, 119.3, 88.0, 79.9, 67.0.
+
HRMS (ESI): m/z: [M + Na]+ calc. For C17H12NaO3 , 287.0679;
found, 287.0680.
2-Oxo-2-(p-tolyl)-ethyl 3-(p-tolyl)-propiolate (2b). Purification
was performed by column chromatography (petroleum ether/ethyl
acetate = 15/1) to afford 44 mg (50%) of 2b. White solid, mp 167−
168 °C. 1H NMR (600 MHz, CDCl3) δ 7.84 (d, J = 8.2 Hz, 2H), 7.52
(d, J = 8.1 Hz, 2H), 7.30 (d, J = 8.0 Hz, 2H), 7.20 (d, J = 7.9 Hz, 2H),
5.47 (s, 2H), 2.43 (s, 3H), 2.39 (s, 3H). 13C{1H} NMR (151 MHz,
CDCl3) δ 190.6, 153.4, 145.1, 141.6, 133.1, 131.4, 129.6, 129.4, 127.9,
116.2, 88.5, 79.7, 66.9, 21.79, 21.76. HRMS (ESI): m/z: [M + Na]+
+
calc. For C19H16NaO3 , 315.0992; found, 315.0988.
2-(4-Fluorophenyl)-2-oxoethyl 3-(4-fluorophenyl)-propiolate
(2c). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 10/1) to afford 75 mg (83%) of
2c. White solid, mp 76−77 °C. 1H NMR (600 MHz, CDCl3) δ 8.01−
7.96 (m, 2H), 7.66−7.59 (m, 2H), 7.22−7.16 (m, 2H), 7.13−7.06
(m, 2H), 5.47 (s, 2H). 13C{1H} NMR (151 MHz, CDCl3) δ 189.4,
166.2 (d, JC‑F = 256.6 Hz), 164.0 (d, JC‑F = 253.9 Hz), 153.1, 135.4
(d, JC‑F = 8.9 Hz), 130.5 (d, JC‑F = 9.5 Hz), 130.2 (d, JC‑F = 3.1 Hz),
116.2 (d, JC‑F = 3.3 Hz), 116.1 (d, JC‑F = 3.6 Hz), 115.3 (d, JC‑F = 3.5
Hz), 87.0, 79.7, 66.8. HRMS (ESI): m/z: [M + Na]+ calc. For
+
C17H10F2NaO3 , 323.0490; found, 323.0485.
General Procedure for the Synthesis of α-Acyloxy Ketones
5a−5d, 5f−5n, and 5p. Propiolic acid 1 (0.60 mmol, 1.0 equiv),
terminal alkyne 4 (1.2 mmol, 2.0 equiv), PhI(OAc)2 (773 mg, 2.4
mmol, 4.0 equiv), copper quinolate (15.9 mg, 0.045 mmol, 0.075
equiv), KHCO3 (60 mg, 0.6 mmol, 1.0 equiv), toluene (4.5 mL), and
H2O (1.5 mL) were added in a sealed tube with a Teflon-lined cap.
The mixture was allowed to stir at 70 °C (oil bath temperature) under
air for 12 h. After cooling to room temperature, 4 mL of saturated
NaHCO3 solution was added and extracted with ethyl acetate. The
organic phase was dried over anhydrous Na2SO4 and filtered. The
filtrate was concentrated by rotary evaporation and purified by flash
chromatography on silica gel with petroleum ether/ethyl acetate or
petroleum ether/dichloromethane as the eluent to afford the
corresponding product.
2-(4-Chlorophenyl)-2-oxoethyl 3-(4-chlorophenyl)-propiolate
(2d). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 15/1) to afford 77 mg (77%) of
1
2d. White solid, mp 167−168 °C. H NMR (600 MHz, CDCl3) δ
7.88 (d, J = 8.6 Hz, 2H), 7.56 (d, J = 8.5 Hz, 2H), 7.49 (d, J = 8.6 Hz,
2H), 7.39 (d, J = 8.5 Hz, 2H), 5.46 (s, 2H).13C{1H} NMR (151 MHz,
CDCl3) δ 189.8, 153.0, 140.7, 137.4, 134.3, 132.1, 129.3, 129.2, 129.1,
117.7, 86.8, 80.6, 66.9. HRMS (ESI): m/z: [M + Na]+ calc. For
+
C17H10Cl2NaO3 , 354.9899; found, 354.9896.
2-(4-Bromophenyl)-2-oxoethyl 3-(4-bromophenyl)-propiolate
(2e). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 15/1) to afford 82 mg (65%) of
1
2e. White solid, mp 165−167 °C. H NMR (600 MHz, CDCl3) δ
7.80 (d, J = 8.6 Hz, 2H), 7.66 (d, J = 8.6 Hz, 2H), 7.59−7.52 (m,
2H), 7.52−7.44 (m, 2H), 5.45 (s, 2H). 13C{1H} NMR (151 MHz,
CDCl3) δ 189.0, 153.0, 134.4, 132.5, 132.3, 132.1, 129.5, 129.3, 125.8,
118.2, 86.9, 80.7, 66.9. HRMS (ESI): m/z: [M + Na]+ calc. For
Typical Procedure for the Synthesis of α-Acyloxy Ketones
5e. Terminal alkyne 4a (122 mg, 1.2 mmol, 2.0 equiv), PhI(OAc)2
(773 mg, 2.4 mmol, 4.0 equiv), copper quinolate (15.9 mg, 0.045
mmol, 0.075 equiv), KHCO3 (60 mg, 0.6 mmol, 1.0 equiv), and H2O
(1.5 mL) were added in a sealed tube. Then, the solution of propiolic
+
C17H10Br2NaO3 , 442.8889; found, 442.8901.
8220
https://doi.org/10.1021/acs.joc.1c00669
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Article
2-Oxo-2-(4-(trifluoromethoxy)-phenyl)-ethyl 3-(4-(trifluorome-
thoxy)-phenyl)-propiolate (2f). Purification was performed by
column chromatography (petroleum ether/ethyl acetate = 30/1) to
afford 106 mg (82%) of 2f. White solid, mp 101−103 °C. H NMR
22.6 Hz), 86.3 (d, JC‑F = 3.4 Hz), 80.2, 67.0. HRMS (ESI): m/z: [M +
+
Na]+ calc. For C17H10F2NaO3 , 323.0490; found, 323.0488.
2-(3-Chlorophenyl)-2-oxoethyl 3-(3-chlorophenyl)-propiolate
(2m). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 10/1) to afford 82 mg (82%) of
1
(600 MHz, CDCl3) δ 8.05−7.94 (m, 2H), 7.67 (d, J = 8.5 Hz, 2H),
7.35 (d, J = 8.6 Hz, 2H), 7.25 (d, J = 8.3 Hz, 2H), 5.48 (s, 2H).
13C{1H} NMR (151 MHz, CDCl3) δ 189.5, 153.3, 152.9, 150.8,
134.9, 131.9, 130.0, 120.9, 120.7, 120.2 (q, JC‑F = 258.8 Hz), 120.2 (q,
JC‑F = 259.4 Hz), 117.8, 86.4, 80.4, 66.9. HRMS (ESI): m/z: [M +
1
2m. White solid, mp 100−102 °C. H NMR (600 MHz, CDCl3) δ
7.92 (t, J = 1.8 Hz, 1H), 7.83−7.79 (m, 1H), 7.63−7.58 (m, 2H),
7.55−7.50 (m, 1H), 7.49−7.43 (m, 2H), 7.35 (t, J = 7.9 Hz, 1H),
5.46 (s, 2H). 13C{1H} NMR (151 MHz, CDCl3) δ 189.7, 152.8,
135.4, 135.2, 134.5, 134.1, 132.8, 131.3, 131.2, 130.3, 129.9, 128.0,
125.9, 121.0, 86.2, 80.5, 67.0. HRMS (ESI): m/z: [M + Na]+ calc. For
+
Na]+ calc. For C19H10F6NaO5 , 455.0325; found, 455.0319.
2-(4-Formylphenyl)-2-oxoethyl 3-(4-formylphenyl)-propiolate
(2g). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 3/1) to afford 46 mg (48%) of
+
C17H10Cl2NaO3 , 354.9899; found, 354.9906.
2-(3-Bromophenyl)-2-oxoethyl 3-(3-bromophenyl)-propiolate
(2n). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 10/1) to afford 88 mg (70%) of
1
2g. White solid, mp 159−160 °C. H NMR (600 MHz, CDCl3) δ
10.14 (s, 1H), 10.07 (s, 1H), 8.11 (d, J = 7.8 Hz, 2H), 8.04 (d, J = 8.0
Hz, 2H), 7.93 (d, J = 7.8 Hz, 2H), 7.79 (d, J = 7.8 Hz, 2H), 5.54 (s,
2H). 13C{1H} NMR (151 MHz, CDCl3) δ 191.3, 191.2, 190.3, 152.7,
139.7, 137.8, 137.2, 133.6, 130.1, 129.6, 128.4, 125.1, 86.2, 82.2, 67.3.
1
2n. White solid, mp 110−112 °C. H NMR (600 MHz, CDCl3) δ
8.07 (t, J = 1.7 Hz, 1H), 7.88−7.83 (m, 1H), 7.79−7.73 (m, 2H),
7.64−7.58 (m, 1H), 7.58−7.53 (m, 1H), 7.40 (t, J = 7.9 Hz, 1H),
7.29 (d, J = 8.0 Hz, 1H), 5.46 (s, 2H). 13C{1H} NMR (151 MHz,
CDCl3) δ 189.6, 152.8, 137.0, 135.6, 135.4, 134.1, 131.6, 130.9, 130.5,
130.1, 126.3, 123.3, 122.3, 121.2, 86.0, 80.5, 66.9. HRMS (ESI): m/z:
+
HRMS (ESI): m/z: [M + Na]+ calc. For C19H12NaO5 , 343.0577;
found, 343.0587.
2-(4-Acetylphenyl)-2-oxoethyl 3-(4-acetylphenyl)-propiolate
(2h). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 2.5/1) to afford 55 mg (53%) of
+
[M + Na]+ calc. For C17H10Br2NaO3 , 442.8889; found, 442.8899.
2-Oxo-2-(3-(trifluoromethoxy)-phenyl)-ethyl 3-(3-(trifluorome-
thoxy)-phenyl)-propiolate (2o). Purification was performed by
column chromatography (petroleum ether/ethyl acetate = 20/1) to
1
2h. White solid, mp 154−156 °C. H NMR (600 MHz, CDCl3) δ
8.09 (d, J = 8.5 Hz, 2H), 8.03 (d, J = 8.4 Hz, 2H), 7.99 (d, J = 8.4 Hz,
2H), 7.73 (d, J = 8.4 Hz, 2H), 5.53 (s, 2H), 2.67 (s, 3H), 2.64 (s,
3H). 13C{1H} NMR (151 MHz, CDCl3) δ 197.2, 197.1, 190.4, 152.8,
140.9, 138.2, 136.8, 133.2, 128.8, 128.3, 128.1, 123.8, 86.5, 81.8, 67.2,
1
afford 100 mg (77%) of 2o. White solid, mp 59−60 °C. H NMR
(600 MHz, CDCl3) δ 7.86 (d, J = 7.8 Hz, 1H), 7.80 (s, 1H), 7.60−
7.54 (m, 2H), 7.52−7.47 (m, 2H), 7.45 (t, J = 8.0 Hz, 1H), 7.37−
7.32 (m, 1H), 5.49 (s, 2H). 13C{1H} NMR (151 MHz, CDCl3) δ
189.5, 152.8, 149.6 (d, JC‑F = 1.7 Hz), 149.0 (d, JC‑F = 1.8 Hz), 135.5,
+
26.9, 26.8. HRMS (ESI): m/z: [M + Na]+ calc. For C21H16NaO5 ,
371.0890; found, 371.0883.
131.4, 130.6, 130.3, 126.5, 126.1, 125.2, 123.7, 121.1, 120.29 (q, JC‑F
=
2-(4-Cyanophenyl)-2-oxoethyl 3-(4-cyanophenyl)-propiolate
(2i). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 3/1) to afford 41 mg (43%) of 2i.
258.6 Hz), 120.26 (q, JC‑F = 258.4 Hz), 117.7, 85.9, 80.5, 67.0. HRMS
+
(ESI): m/z: [M + Na]+ calc. For C19H10F6NaO5 , 455.0325; found,
1
White solid, mp 168−170 °C. H NMR (600 MHz, CDCl3) δ 8.04
455.0322.
(d, J = 8.4 Hz, 2H), 7.84 (d, J = 8.4 Hz, 2H), 7.75−7.68 (m, 4H),
5.50 (s, 2H). 13C{1H} NMR (151 MHz, CDCl3) δ 189.6, 152.5,
136.6, 133.4, 132.8, 132.3, 128.3, 123.9, 117.7, 117.52, 117.48, 114.4,
85.4, 82.4, 67.1. HRMS (ESI): m/z: [M + Na]+ calc. For
2-(3-Nitrophenyl)-2-oxoethyl 3-(3-nitrophenyl)-propiolate (2p).
Purification was performed by column chromatography (petroleum
ether/ethyl acetate = 3/1) to afford 79 mg (74%) of 2p. Yellow solid,
mp 105−107 °C. 1H NMR (600 MHz, CDCl3) δ 8.77 (t, J = 1.8 Hz,
1H), 8.56−8.47 (m, 2H), 8.38−8.33 (m, 1H), 8.32−8.27 (m, 1H),
7.98−7.93 (m, 1H), 7.78 (t, J = 8.0 Hz, 1H), 7.65 (t, J = 8.0 Hz, 1H),
5.56 (s, 2H). 13C{1H} NMR (151 MHz, CDCl3) δ 188.9, 152.4,
148.4, 148.1, 138.5, 134.9, 133.4, 130.4, 129.9, 128.4, 127.9, 125.6,
122.8, 121.0, 84.8, 81.2, 67.1. HRMS (ESI): m/z: [M + Na]+ calc. For
+
C19H10N2NaO3 , 337.0584; found, 337.0593.
2-Oxo-2-(4-(trifluoromethyl)-phenyl)-ethyl 3-(4-(trifluorometh-
yl)-phenyl)-propiolate (2j). Purification was performed by column
chromatography (petroleum ether/ethyl acetate = 20/1) to afford 97
1
mg (81%) of 2j. White solid, mp 156−158 °C. H NMR (600 MHz,
+
CDCl3) δ 8.06 (d, J = 8.1 Hz, 2H), 7.80 (d, J = 8.2 Hz, 2H), 7.75 (d, J
= 8.1 Hz, 2H), 7.68 (d, J = 8.2 Hz, 2H), 5.52 (s, 2H). 13C{1H} NMR
(151 MHz, CDCl3) δ 190.0, 152.7, 136.4, 135.4 (q, JC‑F = 33.0 Hz),
133.3, 132.5 (q, JC‑F = 33.1 Hz), 128.2, 126.1 (q, JC‑F = 3.6 Hz), 125.6
(q, JC‑F = 3.7 Hz), 123.4 (q, JC‑F = 272.6 Hz), 123.3 (q, JC‑F = 272.9
Hz), 123.0, 86.0, 81.2, 67.1. HRMS (ESI): m/z: [M + Na]+ calc. For
C17H10N2NaO7 , 377.0380; found, 377.0390.
2-Oxo-2-(3-(trifluoromethyl)-phenyl)-ethyl 3-(3-(trifluorometh-
yl)-phenyl)-propiolate (2q). Purification was performed by column
chromatography (petroleum ether/ethyl acetate = 20/1) to afford 109
1
mg (91%) of 2q. White solid, mp 58−60 °C. H NMR (600 MHz,
CDCl3) δ 8.19 (s, 1H), 8.13 (d, J = 7.8 Hz, 1H), 7.90 (d, J = 8.5 Hz,
2H), 7.81 (d, J = 7.7 Hz, 1H), 7.74 (d, J = 7.9 Hz, 1H), 7.69 (t, J = 7.8
Hz, 1H), 7.56 (t, J = 7.8 Hz, 1H), 5.53 (s, 2H). 13C{1H} NMR (151
MHz, CDCl3) δ 189.7, 152.7, 136.1, 134.3, 131.6 (q, JC‑F = 33.2 Hz),
131.3 (q, JC‑F = 33.2 Hz), 131.0, 130.6 (q, JC‑F = 3.5 Hz), 129.9 (q,
+
C19H10F6NaO3 , 423.0426; found, 423.0443.
2-Oxo-2-(m-tolyl)-ethyl 3-(m-tolyl)-propiolate (2k). Purification
was performed by column chromatography (petroleum ether/ethyl
acetate = 15/1) to afford 65 mg (74%) of 2k. Yellow solid, mp 60−62
1
°C. H NMR (600 MHz, CDCl3) δ 7.79−7.69 (m, 2H), 7.47−7.41
JC‑F = 3.8 Hz), 129.7, 129.3, 127.5 (q, JC‑F = 3.5 Hz), 124.7 (q, JC‑F =
(m, 3H), 7.39 (t, J = 7.6 Hz, 1H), 7.32−7.26 (m, 2H), 5.48 (s, 2H),
2.43 (s, 3H), 2.36 (s, 3H). 13C{1H} NMR (151 MHz, CDCl3) δ
191.1, 153.3, 138.8, 138.4, 134.9, 133.9, 133.6, 131.8, 130.2, 128.8,
128.5, 128.3, 124.9, 119.1, 88.3, 79.7, 67.0, 21.3, 21.2. HRMS (ESI):
3.7 Hz), 123.4 (q, JC‑F = 272.6 Hz), 123.3 (q, JC‑F = 272.6 Hz), 120.2,
85.9, 80.7, 67.0. HRMS (ESI): m/z: [M + Na]+ calc. For
+
C19H10F6NaO3 , 423.0426; found, 423.0420.
Methyl-3-(3-(2-(3-(methoxycarbonyl)-phenyl)-2-oxoethoxy)-3-
oxoprop-1-yn-1-yl)-benzoate (2r). Purification was performed by
column chromatography (petroleum ether/ethyl acetate = 5/1) to
+
m/z: [M + Na]+ calc. For C19H16NaO3 , 315.0992; found, 315.0987.
2-(3-Fluorophenyl)-2-oxoethyl 3-(3-fluorophenyl)-propiolate
(2l). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 8/1) to afford 79 mg (88%) of 2l.
Yellow solid, mp 58−59 °C. 1H NMR (600 MHz, CDCl3) δ 7.71 (d, J
= 7.7 Hz, 1H), 7.67−7.61 (m, 1H), 7.54−7.47 (m, 1H), 7.43−7.29
(m, 4H), 7.22−7.17 (m, 1H), 5.48 (s, 2H). 13C{1H} NMR (151
MHz, CDCl3) δ 189.7 (d, JC‑F = 2.1 Hz), 163.3 (d, JC‑F = 108.1 Hz),
161.6 (d, JC‑F = 107.2 Hz), 152.8, 135.6 (d, JC‑F = 6.3 Hz), 130.7 (d,
1
afford 80 mg (70%) of 2r. White solid, mp 117−119 °C. H NMR
(600 MHz, CDCl3) δ 8.56 (d, J = 1.4 Hz, 1H), 8.36−8.24 (m, 2H),
8.16 (m, 2H), 7.81 (d, J = 7.7 Hz, 1H), 7.63 (t, J = 7.8 Hz, 1H), 7.51
(t, J = 7.8 Hz, 1H), 5.55 (s, 2H), 3.98 (s, 3H), 3.95 (s, 3H). 13C{1H}
NMR (151 MHz, CDCl3) δ 190.1, 165.8, 165.7, 152.9, 137.0, 134.8,
134.2, 134.0, 132.0, 131.8, 130.9, 130.7, 129.3, 128.9, 128.8, 119.8,
86.6, 80.3, 67.1, 52.54, 52.46. HRMS (ESI): m/z: [M + Na]+ calc. For
+
J
C‑F = 7.7 Hz), 130.4 (d, JC‑F = 8.5 Hz), 129.0 (d, JC‑F = 3.2 Hz), 123.5
(d, JC‑F = 3.1 Hz), 121.2 (d, JC‑F = 21.4 Hz), 121.0 (d, JC‑F = 9.4 Hz),
119.7 (d, JC‑F = 23.4 Hz), 118.4 (d, JC‑F = 21.2 Hz), 114.6 (d, JC‑F
C21H16NaO7 , 403.0788; found, 403.0798.
2-Oxo-2-(o-tolyl)-ethyl 3-(o-tolyl)-propiolate (2s). Purification
was performed by column chromatography (petroleum ether/ethyl
=
8221
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Article
acetate = 25/1) to afford 28 mg (32%) of 2s. Yellow solid, mp 58−59
°C. 1H NMR (600 MHz, CDCl3) δ 7.67−7.63 (m, 1H), 7.58 (dd, J =
7.7, 0.9 Hz, 1H), 7.45 (td, J = 7.6, 1.2 Hz, 1H), 7.36 (td, J = 7.6, 1.2
Hz, 1H), 7.33−7.28 (m, 2H), 7.25 (d, 1H), 7.20 (t, J = 7.6 Hz, 1H),
5.35 (s, 2H), 2.55 (s, 3H), 2.52 (s, 3H). 13C{1H} NMR (151 MHz,
CDCl3) δ 194.3, 153.4, 142.5, 139.4, 133.8, 133.6, 132.4, 132.4, 130.8,
129.8, 128.1, 125.82, 125.79, 119.2, 87.0, 83.6, 68.1, 21.3, 20.6.
7.51 (m, 5H), 5.66 (s, 2H). 13C{1H} NMR (151 MHz, CDCl3) δ
190.9, 153.4, 135.9, 134.6, 133.9, 132.5, 132.3, 131.2, 129.62, 129.58,
129.0, 128.9, 128.4, 128.3, 128.2, 128.0, 127.89, 127.86, 127.1, 127.0,
123.2, 116.5, 88.5, 80.1, 67.1. HRMS (ESI): m/z: [M + Na]+ calc. For
+
C25H16NaO3 , 387.0992; found, 387.1008.
2-Oxo-2-(thiophen-3-yl)-ethyl 3-(thiophen-3-yl)-propiolate (2z).
Purification was performed by column chromatography (petroleum
ether/ethyl acetate = 10/1) to afford 40 mg (48%) of 2z. Yellow solid,
mp 110−113 °C. 1H NMR (600 MHz, CDCl3) δ 8.16−8.14 (m, 1H),
7.82−7.79 (m, 1H), 7.58 (dd, J = 5.1, 1.2 Hz, 1H), 7.41−7.38 (m,
1H), 7.36−7.33 (m, 1H), 7.27 (d, J = 1.1 Hz, 1H), 5.35 (s,
2H).13C{1H} NMR (151 MHz, CDCl3) δ 185.5, 153.3, 138.3, 134.4,
132.5, 130.2, 127.0, 126.4, 126.2, 118.6, 83.6, 79.9, 67.1. HRMS
+
HRMS (ESI): m/z: [M + Na]+ calc. For C19H16NaO3 , 315.0992;
found, 315.0989.
2-(2-Fluorophenyl)-2-oxoethyl 3-(2-fluorophenyl)-propiolate
(2t). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 20/1) to afford 63 mg (70%) of
1
2t. White solid, mp 74−75 °C. H NMR (600 MHz, CDCl3) δ 8.02
+
(ESI): m/z: [M + Na]+ calc. For C13H8NaO3S2 , 298.9807; found,
(td, J = 7.7, 1.8 Hz, 1H), 7.66−7.56 (m, 2H), 7.52−7.42 (m, 1H),
7.35−7.28 (m, 1H), 7.24−7.17 (m, 2H), 7.14 (t, J = 8.8 Hz, 1H),
5.40 (d, J = 3.8 Hz, 2H). 13C{1H} NMR (151 MHz, CDCl3) δ 189.0
(d, JC‑F = 5.0 Hz), 163.9 (d, JC‑F = 200.6 Hz), 162.2 (d, JC‑F = 198.4
Hz), 152.9, 135.9 (d, JC‑F = 9.2 Hz), 134.7, 132.9 (d, JC‑F = 8.2 Hz),
130.8 (d, JC‑F = 2.9 Hz), 125.0 (d, JC‑F = 3.1 Hz), 124.3 (d, JC‑F = 3.7
Hz), 122.0 (d, JC‑F = 14.5 Hz), 116.6 (d, JC‑F = 23.5 Hz), 115.9 (d,
JC‑F = 20.3 Hz), 108.3 (d, JC‑F = 15.3 Hz), 84.4 (d, JC‑F = 3.2 Hz),
81.2, 70.1 (d, JC‑F = 15.2 Hz). HRMS (ESI): m/z: [M + Na]+ calc.
298.9816.
2-(Cyclohex-1-en-1-yl)-2-oxoethyl 3-(cyclohex-1-en-1-yl)-propio-
late (2aa). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 20/1) to afford 20 mg (24%) of 2aa.
White solid, mp 53−55 °C. 1H NMR (600 MHz, CDCl3) δ 6.86 (dd,
J = 4.7, 3.0 Hz, 1H), 6.49 (td, J = 3.9, 1.9 Hz, 1H), 5.14 (s, 2H),
2.30−2.21 (m, 4H), 2.21−2.12 (m, 4H), 1.69−1.60 (m, 8H).
13C{1H} NMR (151 MHz, CDCl3) δ 191.4, 153.7, 142.7, 141.0,
+
For C17H10F2NaO3 , 323.0490; found, 323.0499.
137.1, 118.4, 90.0, 78.0, 66.0, 27.9, 26.0, 22.7, 21.8, 21.6, 21.4, 21.0.
+
2-(2-Chlorophenyl)-2-oxoethyl 3-(2-chlorophenyl)-propiolate
(2u). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 15/1) to afford 41 mg (41%) of
HRMS (ESI): m/z: [M + Na]+ calc. For C17H20NaO3 , 295.1305;
found, 295.1300.
Methyl 3-(2-((3-(2-chlorophenyl)-propioloyl)-oxy)-acetyl)-ben-
zoate (2cc). Purification was performed by column chromatography
(petroleum ether/dichloromethane = 1/2) to afford 34 mg (16%) of
2cc. White solid, mp 92−94 °C. 1H NMR (600 MHz, CDCl3) δ 8.56
(t, J = 1.5 Hz, 1H), 8.32−8.28 (m, 1H), 8.18−8.14 (m, 1H), 7.66 (dd,
J = 7.7, 1.5 Hz, 1H), 7.62 (t, J = 7.8 Hz, 1H), 7.46 (dd, J = 8.1, 0.9 Hz,
1H), 7.41 (td, J = 7.8, 1.6 Hz, 1H), 7.30 (td, J = 7.6, 1.2 Hz, 1H), 5.55
(s, 2H), 3.98 (s, 3H). 13C{1H} NMR (151 MHz, CDCl3) δ 190.1,
165.9, 152.9, 137.5, 134.9, 134.8, 134.0, 132.0, 131.9, 130.9, 129.6,
129.3, 128.8, 126.7, 119.6, 84.3, 83.9, 67.1, 52.6. HRMS (ESI): m/z:
1
2u. Yellow solid, mp 47−49 °C. H NMR (600 MHz, CDCl3) δ
7.71−7.67 (m, 1H), 7.63 (dd, J = 7.7, 1.4 Hz, 1H), 7.51−7.43 (m,
3H), 7.43−7.36 (m, 2H), 7.29 (td, J = 7.6, 1.2 Hz, 1H), 5.40 (s, 2H).
13C{1H} NMR (151 MHz, CDCl3) δ 193.7, 152.9, 137.5, 135.3,
134.8, 133.2, 131.9, 131.7, 130.7, 130.3, 129.6, 127.2, 126.7, 119.6,
84.2, 83.9, 69.3. HRMS (ESI): m/z: [M + Na]+ calc. For
+
C17H10Cl2NaO3 , 354.9899; found, 354.9913.
2-(2-Bromophenyl)-2-oxoethyl 3-(2-bromophenyl)-propiolate
(2v). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 10/1) to afford 45 mg (35%) of
+
[M + Na]+ calc. For C19H13ClNaO5 , 379.0344; found, 379.0359.
1
Methyl 3-(3-(2-(2-chlorophenyl)-2-oxoethoxy)-3-oxoprop-1-yn-
1-yl)-benzoate (2dd). Purification was performed by column
chromatography (petroleum ether/dichloromethane = 1/2.5) to
2v. Yellow solid, mp 41−42 °C. H NMR (600 MHz, CDCl3) δ
7.68−7.59 (m, 3H), 7.55 (dd, J = 7.6, 1.7 Hz, 1H), 7.43 (td, J = 7.5,
1.1 Hz, 1H), 7.38 (td, J = 7.7, 1.7 Hz, 1H), 7.36−7.30 (m, 2H), 5.35
(s, 2H).13C{1H} NMR (151 MHz, CDCl3) δ 194.9, 152.8, 137.7,
135.0, 133.9, 132.8, 132.0, 129.6, 127.6, 127.2, 126.6, 121.8, 119.3,
85.8, 83.2, 68.6. HRMS (ESI): m/z: [M + Na]+ calc. For
1
afford 20 mg (9%) of 2dd. White solid, mp 124−126 °C. H NMR
(600 MHz, CDCl3) δ 8.30 (t, J = 1.4 Hz, 1H), 8.16−8.12 (m, 1H),
7.81−7.78 (m, 1H), 7.71−7.68 (m, 1H), 7.51−7.46 (m, 3H), 7.42−
7.38 (m, 1H), 5.40 (s, 2H), 3.95 (s, 3H). 13C{1H} NMR (151 MHz,
CDCl3) δ 193.7, 165.8, 152.9, 137.0, 135.3, 134.2, 133.2, 131.81,
131.78, 130.8, 130.7, 130.4, 128.9, 127.3, 119.8, 86.6, 80.3, 69.3, 52.5.
+
C17H10Br2NaO3 , 442.8889; found, 442.8884.
2-Oxo-2-(2-(trifluoromethoxy)-phenyl)-ethyl 3-(2-(trifluorome-
thoxy)-phenyl)-propiolate (2w). Purification was performed by
column chromatography (petroleum ether/ethyl acetate = 15/1) to
afford 93 mg (72%) of 2w. Colorless oil. 1H NMR (600 MHz,
CDCl3) δ 7.94 (d, J = 7.8 Hz, 1H), 7.68 (d, J = 7.8 Hz, 1H), 7.66−
7.59 (m, 1H), 7.52 (dd, J = 11.1, 4.8 Hz, 1H), 7.43 (t, J = 7.6 Hz,
1H), 7.39−7.30 (m, 3H), 5.33 (s, 2H).13C{1H} NMR (151 MHz,
CDCl3) δ 190.9, 152.7, 150.4 (d, JC‑F = 1.8 Hz), 147.7 (d, JC‑F = 1.6
+
HRMS (ESI): m/z: [M + Na]+ calc. For C19H13ClNaO5 , 379.0344;
found, 379.0356.
2-Oxo-2-phenylethyl but-2-ynoate (5a). Purification was per-
formed by column chromatography (petroleum ether/dichloro-
methane = 1/1) to afford 75 mg (62%) of 5a. White solid, mp
70−71 °C. 1H NMR (600 MHz, CDCl3) δ 7.91 (dd, J = 8.3, 1.2 Hz,
2H), 7.62 (t, J = 7.4 Hz, 1H), 7.50 (t, J = 7.8 Hz, 2H), 5.42 (s, 2H),
2.04 (s, 3H). 13C{1H} NMR (151 MHz, CDCl3) δ 190.9, 152.9,
134.0, 133.8, 128.9, 127.8, 87.5, 71.7, 66.8, 3.9. HRMS (ESI): m/z:
Hz), 135.0, 134.6, 132.2, 131.3, 128.0, 127.1, 126.8, 121.1 (d, JC‑F
=
1.6 Hz), 120.33 (q, JC‑F = 259.5 Hz) , 120.25 (q, JC‑F = 260.4 Hz),
120.0 (d, JC‑F = 1.6 Hz), 114.1, 84.1, 81.6, 69.6. HRMS (ESI): m/z:
+
[M + Na]+ calc. For C12H10NaO3 , 225.0522; found, 225.0522.
+
[M + Na]+ calc. For C19H10F6NaO5 , 455.0325; found, 455.0345.
2-Oxo-2-phenylethyl pent-2-ynoate (5b). Purification was per-
2-(3,5-Dimethylphenyl)-2-oxoethyl 3-(3,5-dimethylphenyl)-pro-
piolate (2x). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 20/1) to afford 54 mg (56%) of 2x.
formed by column chromatography (petroleum ether/ethyl acetate =
1
10/1) to afford 69 mg (53%) of 5b. White solid, mp 31−32 °C. H
1
NMR (600 MHz, CDCl3) δ 7.96−7.87 (m, 2H), 7.66−7.58 (m, 1H),
7.50 (t, J = 7.8 Hz, 2H), 5.43 (s, 2H), 2.40 (q, J = 7.5 Hz, 2H), 1.24
(t, J = 7.5 Hz, 3H). 13C{1H} NMR (151 MHz, CDCl3) δ 190.9,
153.0, 134.0, 133.8, 128.9, 127.7, 92.6, 71.7, 66.8, 12.5, 12.4. HRMS
Yellow solid, mp 86−87 °C. H NMR (600 MHz, CDCl3) δ 7.54 (s,
2H), 7.24 (s, 3H), 7.09 (s, 1H), 5.46 (s, 2H), 2.37 (s, 6H), 2.31 (s,
6H). 13C{1H} NMR (151 MHz, CDCl3) δ 191.2, 153.3, 138.6, 138.2,
135.7, 133.9, 132.8, 130.7, 125.5, 118.9, 88.5, 79.4, 67.0, 21.2, 21.0.
+
(ESI): m/z: [M + Na]+ calc. For C13H12NaO3 , 239.0679; found,
+
HRMS (ESI): m/z: [M + Na]+ calc. For C21H20NaO3 , 343.1305;
239.0686.
found, 343.1300.
2-Oxo-2-phenylethyl hex-2-ynoate (5c). Purification was per-
2-(Naphthalen-2-yl)-2-oxoethyl 3-(naphthalen-2-yl)-propiolate
(2y). Purification was performed by column chromatography
(petroleum ether/ethyl acetate = 10/1) to afford 22 mg (20%) of
formed by column chromatography (petroleum ether/ethyl acetate =
1
10/1) to afford 83 mg (60%) of 5c. Colorless oil. H NMR (600
1
2y. Yellow solid, mp 135−137 °C. H NMR (600 MHz, CDCl3) δ
MHz, CDCl3) δ 7.92 (dd, J = 8.3, 1.2 Hz, 2H), 7.65−7.59 (m, 1H),
7.50 (dd, J = 10.8, 4.9 Hz, 2H), 5.42 (s, 2H), 2.36 (t, J = 7.1 Hz, 2H),
1.69−1.60 (m, 2H), 1.04 (t, J = 7.4 Hz, 3H). 13C{1H} NMR (151
8.46 (s, 1H), 8.20 (s, 1H), 8.03−7.96 (m, 2H), 7.94 (d, J = 8.6 Hz,
1H), 7.90 (d, J = 8.1 Hz, 1H), 7.85 (dd, J = 8.2, 2.8 Hz, 3H), 7.67−
8222
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Article
MHz, CDCl3) δ 191.0, 153.0, 134.0, 133.8, 128.9, 127.7, 91.4, 72.4,
66.8, 20.9, 20.7, 13.5. HRMS (ESI): m/z: [M + Na]+ calc. For
C14H14NaO3 , 253.0835; found, 253.0844.
2-Oxo-2-(4-(trimethylsilyl)phenyl)ethyl but-2-ynoate (5l). Purifi-
cation was performed by column chromatography (petroleum ether/
dichloromethane = 3/2) to afford 79 mg (49%) of 5l. White solid, mp
54−56 °C. 1H NMR (600 MHz, CDCl3) δ 7.86 (d, J = 8.0 Hz, 2H),
7.64 (d, J = 8.0 Hz, 2H), 5.42 (s, 2H), 2.04 (s, 3H), 0.30 (s, 9H).
13C{1H} NMR (151 MHz, CDCl3) δ 191.2, 152.9, 148.6, 133.9,
133.7, 126.6, 87.5, 71.7, 66.8, 3.9, −1.4. HRMS (ESI): m/z: [M +
Na]+ calc. For C15H18NaO3Si+, 297.0917; found, 297.0919.
+
2-Oxo-2-phenylethyl 4,4-dimethylpent-2-ynoate (5d). Purifica-
tion was performed by column chromatography (petroleum ether/
ethyl acetate = 10/1) to afford 82 mg (56%) of 5d. White solid, mp
79−81 °C. 1H NMR (600 MHz, CDCl3) δ 7.91 (d, J = 7.8 Hz, 2H),
7.62 (t, J = 7.4 Hz, 1H), 7.49 (t, J = 7.7 Hz, 2H), 5.42 (s, 2H), 1.31 (s,
9H). 13C{1H} NMR (151 MHz, CDCl3) δ 191.0, 153.1, 134.0, 133.8,
128.8, 127.7, 98.3, 71.0, 66.7, 29.8, 27.6. HRMS (ESI): m/z: [M +
2-(Naphthalen-2-yl)-2-oxoethyl but-2-ynoate (5m). Purification
was performed by column chromatography (petroleum ether/
dichloromethane = 20/1) to afford 86 mg (57%) of 5m. Yellow
solid, mp 113−114 °C. 1H NMR (600 MHz, CDCl3) δ 8.40 (s, 1H),
7.99−7.92 (m, 2H), 7.89 (dd, J = 18.0, 8.4 Hz, 2H), 7.65−7.59 (m,
1H), 7.56 (t, J = 7.5 Hz, 1H), 5.55 (s, 2H), 2.03 (s, 3H). 13C{1H}
NMR (151 MHz, CDCl3) δ 190.9, 152.9, 135.8, 132.2, 131.1, 129.5,
128.9, 128.8, 127.8, 127.0, 123.1, 87.5, 71.7, 66.9, 3.9. HRMS (ESI):
+
Na]+ calc. For C15H16NaO3 , 267.0992; found, 267.0993.
2-oxo-2-phenylethyl propiolate (5e). Purification was performed
by column chromatography (petroleum ether/dichloromethane = 1/
1) to afford 51 mg (46%) of 5e. White solid, mp 73−74 °C. 1H NMR
(600 MHz, CDCl3) δ 7.94−7.88 (m, 2H), 7.66−7.60 (m, 1H), 7.51
(t, J = 7.8 Hz, 2H), 5.46 (s, 2H), 3.04 (s, 1H). 13C{1H} NMR (151
MHz, CDCl3) δ 190.4, 151.9, 134.2, 133.6, 128.9, 127.7, 76.4, 73.9,
+
m/z: [M + Na]+ calc. For C16H12NaO3 , 275.0679; found, 275.0685.
+
67.1. HRMS (ESI): m/z: [M + Na]+ calc. For C11H8NaO3 ,
2-Oxohexyl but-2-ynoate (5n). Purification was performed by
211.0366; found, 211.0363.
column chromatography (petroleum ether/dichloromethane = 20/1)
to afford 23 mg (21%) of 5n. Colorless oil. H NMR (600 MHz,
1
2-(3-Chlorophenyl)-2-oxoethyl but-2-ynoate (5f). Purification
was performed by column chromatography (petroleum ether/
dichloromethane = 3/2) to afford 70 mg (50%) of 5f. White solid,
CDCl3) δ 4.72 (s, 2H), 2.43 (t, J = 7.5 Hz, 2H), 2.03 (s, 3H), 1.64−
1.54 (m, 2H), 1.37−1.30 (m, 2H), 0.91 (t, J = 7.4 Hz, 3H). 13C{1H}
NMR (151 MHz, CDCl3) δ 203.0, 152.8, 87.5, 71.6, 68.6, 38.5, 25.2,
22.2, 13.8, 3.9. HRMS (ESI): m/z: [M + Na]+ calc. For
1
mp 93−95 °C. H NMR (600 MHz, CDCl3) δ 7.88 (t, J = 1.7 Hz,
1H), 7.78 (d, J = 7.8 Hz, 1H), 7.61−7.57 (m, 1H), 7.45 (t, J = 7.9 Hz,
1H), 5.38 (s, 2H), 2.04 (s, 3H). 13C{1H} NMR (151 MHz, CDCl3) δ
189.9, 152.7, 135.3, 135.2, 133.9, 130.2, 127.8, 125.8, 87.8, 71.5, 66.6,
+
C10H14NaO3 , 205.0835; found, 205.0835.
2-oxo-2-phenylethyl cinnamate (5o). Purification was performed
3.9. HRMS (ESI): m/z: [M + Na]+ calc. For C12H9ClNaO3 ,
+
by column chromatography (petroleum ether/dichloromethane = 1/
1
1) to afford 58 mg (36%) of 5o. White solid, mp 116−117 °C. H
259.0132; found, 259.0135.
NMR (600 MHz, CDCl3) δ 7.96 (d, J = 7.6 Hz, 2H), 7.82 (d, J = 16.0
Hz, 1H), 7.62 (t, J = 7.3 Hz, 1H), 7.60−7.54 (m, 2H), 7.51 (t, J = 7.7
Hz, 2H), 7.45−7.37 (m, 3H), 6.61 (d, J = 16.0 Hz, 1H), 5.49 (s, 2H).
13C{1H} NMR (151 MHz, CDCl3) δ 192.2, 166.3, 146.2, 134.2,
133.9, 130.5, 128.88, 128.85, 128.2, 127.8, 116.9, 66.1. HRMS (ESI):
2-Oxo-2-(p-tolyl)ethyl but-2-ynoate (5g). Purification was per-
formed by column chromatography (petroleum ether/dichloro-
methane = 3/2) to afford 63 mg (49%) of 5g. White solid, mp
78−80 °C. 1H NMR (600 MHz, CDCl3) δ 7.81 (d, J = 8.2 Hz, 2H),
7.30−7.25 (m, 2H), 5.39 (s, 2H), 2.42 (s, 3H), 2.03 (s, 3H). 13C{1H}
NMR (151 MHz, CDCl3) δ 190.5, 152.8, 145.0, 131.3, 129.5, 127.8,
87.3, 71.7, 66.7, 21.7, 3.9. HRMS (ESI): m/z: [M + Na]+ calc. For
+
m/z: [M + Na]+ calc. For C17H14NaO3 , 289.0835; found, 289.0835.
2-oxo-2-phenylethyl cyclobutanecarboxylate (5p). Purification
was performed by column chromatography (petroleum ether/
dichloromethane = 1/1) to afford 28 mg (21%) of 5p. Colorless
+
C13H12NaO3 , 239.0679; found, 239.0679.
2-(4-Fluorophenyl)-2-oxoethyl but-2-ynoate (5h). Purification
was performed by column chromatography (petroleum ether/
dichloromethane = 3/2) to afford 74 mg (56%) of 5h. White solid,
1
oil. H NMR (600 MHz, CDCl3) δ 7.92 (dd, J = 8.3, 1.2 Hz, 2H),
7.64−7.59 (m, 1H), 7.52−7.46 (m, 2H), 5.35 (s, 2H), 3.42−3.28 (m,
1H), 2.48−2.35 (m, 2H), 2.34−2.23 (m, 2H), 2.07−1.91 (m, 2H).
13C{1H} NMR (151 MHz, CDCl3) δ 192.4, 174.9, 134.2, 133.8,
128.8, 127.7, 65.8, 37.7, 25.2, 18.4. HRMS (ESI): m/z: [M + Na]+
1
mp 73−74 °C. H NMR (600 MHz, CDCl3) δ 8.00−7.91 (m, 2H),
7.18 (t, J = 8.6 Hz, 2H), 5.39 (s, 2H), 2.04 (s, 3H). 13C{1H} NMR
(151 MHz, CDCl3) δ 189.5, 166.1 (d, JC‑F = 256.3 Hz), 152.8, 130.5
(d, JC‑F = 9.5 Hz), 130.3 (d, JC‑F = 3.0 Hz), 116.1 (d, JC‑F = 22.0 Hz),
87.7, 71.6, 66.6, 3.9. HRMS (ESI): m/z: [M + Na]+ calc. For
+
calc. For C13H14NaO3 , 241.0835; found, 241.0837.
+
C12H9FNaO3 , 243.0428; found, 243.0431.
ASSOCIATED CONTENT
* Supporting Information
■
2-(4-Fluorophenyl)-2-oxoethyl 4,4-dimethylpent-2-ynoate (5i).
Purification was performed by column chromatography (petroleum
ether/dichloromethane = 20/1) to afford 101 mg (64%) of 5i. White
sı
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.joc.1c00669.
1
solid, mp 81−83 °C. H NMR (600 MHz, CDCl3) δ 7.99−7.92 (m,
2H), 7.17 (t, J = 8.6 Hz, 2H), 5.38 (s, 2H), 1.31 (s, 9H). 13C{1H}
NMR (151 MHz, CDCl3) δ 189.6, 166.1 (d, JC‑F = 256.3 Hz), 153.1,
130.5 (d, JC‑F = 9.5 Hz), 130.3 (d, JC‑F = 3.1 Hz), 116.1 (d, JC‑F = 22.1
Hz), 98.5, 70.9, 66.5, 29.8, 27.6. HRMS (ESI): m/z: [M + Na]+ calc.
Optimization of the reaction conditions; experimental
1
procedures; and H NMR and 13C NMR spectra of
compounds (PDF).
+
For C15H15FNaO3 , 285.0897; found, 285.0899.
2-(4-Cyanophenyl)-2-oxoethyl but-2-ynoate (5j). Purification was
performed by column chromatography (petroleum ether/dichloro-
methane = 1/2) to afford 54 mg (39%) of 5j. White solid, mp 132−
134 °C. 1H NMR (600 MHz, CDCl3) δ 8.01 (d, J = 8.2 Hz, 2H), 7.82
(d, J = 8.2 Hz, 2H), 5.39 (s, 2H), 2.05 (s, 3H). 13C{1H} NMR (151
MHz, CDCl3) δ 190.1, 152.7, 136.8, 132.7, 128.3, 117.6, 117.2, 88.1,
71.4, 66.7, 4.0. HRMS (ESI): m/z: [M + Na]+ calc. For
AUTHOR INFORMATION
Corresponding Author
■
Ya-Min Li − Faculty of Life Science and Technology, Kunming
University of Science and Technology, Kunming 650500, P.
R. China; orcid.org/0000-0003-4233-5274;
Email: liym@kust.edu.cn
+
C13H9NNaO3 , 250.0475; found, 250.0475.
2-(4-(tert-Butyl)phenyl)-2-oxoethyl but-2-ynoate (5k). Purifica-
tion was performed by column chromatography (petroleum ether/
dichloromethane = 3/2) to afford 73 mg (47%) of 5k. White solid,
Authors
Xin Chen − Faculty of Life Science and Technology, Kunming
University of Science and Technology, Kunming 650500, P.
R. China
Yangchun Xin − Katzin Diagnostic & Research PET/MR
Center, Nemours/Alfred I. DuPont Hospital for Children,
Wilmington, Delaware 19803, United States
1
mp 85−86 °C. H NMR (600 MHz, CDCl3) δ 7.86 (d, J = 8.4 Hz,
2H), 7.50 (d, J = 8.4 Hz, 2H), 5.41 (s, 2H), 2.03 (s, 3H), 1.34 (s,
9H). 13C{1H} NMR (151 MHz, CDCl3) δ 190.5, 157.8, 152.8, 131.2,
127.7, 125.8, 87.3, 71.7, 66.7, 35.2, 30.9, 3.9. HRMS (ESI): m/z: [M
+
+ Na]+ calc. For C16H18NaO3 , 281.1148; found, 281.1149.
8223
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J. Org. Chem. 2021, 86, 8216−8225

The Journal of Organic Chemistry
pubs.acs.org/joc
Article
Acids. Angew. Chem., Int. Ed. 2011, 50, 5331−5334. (e) Zhang, Q.-B.;
Ban, Y.-L.; Zhou, D.-G.; Zhou, P.-P.; Wu, L.-Z.; Liu, Q. Preparation of
α-Acyloxy Ketones via Visible-Light-Driven Aerobic Oxo-Acyloxyla-
tion of Olefins with Carboxylic Acids. Org. Lett. 2016, 18, 5256−
5259. (f) Mo, D.-L.; Dai, L.-X.; Hou, X.-L. The Reaction of Terminal
Alkynes with PhI(OAc)2: A Convenient Procedure for the
Preparation of α-Acyloxy Ketones. Tetrahedron Lett. 2009, 50,
3039−5259. (g) Liu, Q.-R.; Pan, C.-X.; Ma, X.-P.; Mo, D.-L.; Su,
G.-F. (Diacetoxyiodo)benzene-Mediated Reaction of Ethynylcarbi-
nols: Entry to α,α′-Diacetoxy Ketones and Glycerol Derivatives. J.
Org. Chem. 2015, 80, 6496−6501. (h) Srinivas, B. T. V.; Rawat, V. S.;
Sreedhar, B. Iron-Catalyzed Dioxygenation of Alkenes and Terminal
Alkynes by Using (Diacetoxyiodo)benzene as Oxidant. Adv. Synth.
Catal. 2015, 357, 3587−3596.
Zhi-Wei Zhao − Faculty of Life Science and Technology,
Kunming University of Science and Technology, Kunming
650500, P. R. China
Yu-Jian Hou − Faculty of Life Science and Technology,
Kunming University of Science and Technology, Kunming
650500, P. R. China
Xiang-Xiang Wang − Faculty of Life Science and Technology,
Kunming University of Science and Technology, Kunming
650500, P. R. China
Wen-Jin Xia − Faculty of Life Science and Technology,
Kunming University of Science and Technology, Kunming
650500, P. R. China
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.joc.1c00669
(5) For recent reviews on decarboxylation, see (a) Baudoin, O. New
Approaches for Decarboxylative Biaryl Coupling. Angew. Chem., Int.
Ed. 2007, 46, 1373−1375. (b) Satoh, T.; Miura, M. Transition-Metal-
Catalyzed Regioselective Arylation and Vinylation of Carboxylic
Acids. Synthesis 2010, 42, 3395−1375. (c) Rodriguez, N.; Gooßen, L.
J. Decarboxylative Coupling Reactions: A Modern Strategy for C−C
Bond Formation. Chem. Soc. Rev. 2011, 40, 5030. (d) Li, Z.; Jiang, Y.-
Y.; Yeagley, A. A.; Bour, J. P.; Liu, L.; Chruma, J. J.; Fu, Y. Mechanism
of the Pd-Catalyzed Decarboxylative Allylation of α-Imino Esters:
Decarboxylation via Free Carboxylate Ion. Chem.−Eur. J. 2012, 18,
14527−14538. (e) Wei, Y.; Hu, P.; Zhang, M.; Su, W. Metal-
Catalyzed Decarboxylative C−H Functionalization. Chem. Rev. 2017,
117, 8864−8907. (f) Penteado, F.; Lopes, E. F.; Alves, D.; Perin, G.;
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We gratefully acknowledge financial support from the National
Natural Science Foundation of China (21871114), Ronald J
Quinn AM Academician Workstation (2019IC003), and the
Program for Innovative Research Team (in Science and
Technology) in the Universities of Yunnan Province.
Jacob, R. G.; Lenardao, E. J. α-Keto Acids: Acylating Agents in
̃
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