Synthesis of functionalized oxazoles via silver-catalyzed cyclization of propargylamides and allenylamides

Article abstract of DOI:10.1021/jo401330t

Silver(I)-catalyzed [3,3] rearrangement of N-sulfonyl propargylamides affords functionalized oxazoles with highly regioselective migration of the sulfonyl group by the introduction of acyloxy groups. The allenylamides, generated from the corresponding propargylamides, can also undergo the silver-catalyzed cyclization to give various 5-vinyloxazoles.

Full text of DOI:10.1021/jo401330t

Article
pubs.acs.org/joc
Synthesis of Functionalized Oxazoles via Silver-Catalyzed Cyclization
of Propargylamides and Allenylamides
Yancheng Hu, Ruxia Yi, Fan Wu, and Boshun Wan*
Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
S
* Supporting Information
ABSTRACT: Silver(I)-catalyzed [3,3] rearrangement of N-
sulfonyl propargylamides affords functionalized oxazoles with
highly regioselective migration of the sulfonyl group by the
introduction of acyloxy groups. The allenylamides, generated
from the corresponding propargylamides, can also undergo the
silver-catalyzed cyclization to give various 5-vinyloxazoles.
sulfonyl propargylamides, which could undergo the silver-
catalyzed cyclization smoothly via sulfonyl migration (Scheme
1, eq 3).
INTRODUCTION
■
Oxazoles are regarded as privileged heterocyclic motifs in
numerous bioactive natural products, synthetic intermediates,
and pharmaceuticals.1 Consequently, many new methods,
including the intramolecular cyclization of preformed pre-
cursors,2 the oxidative coupling of amines and ketone
derivatives,3 and one-step bimolecular annulation,4 have been
widely developed to form oxazoles. Of note, the cyclization of
propargylamides to the corresponding oxazole derivatives has
been a focus of interest. These transformations have been
achieved with transition metal,2e−l acid,2m,n and base2o−r
catalysts. According to these previous works, it is well-known
that the transition-metal-catalyzed cyclization of propargyla-
mides generally proceeds through 5-exo-dig mode to give
oxazole derivatives. Despite the impressive achievements made
in this area, it is still highly desirable to explore more efficient
and practical alternatives for the synthesis of functionalized
oxazoles. Recently, the synthesis of heterocycles accompanied
with sulfonyl migration has gained much attention, and much
progress has been achieved.5 We have previously reported the
base-catalyzed cyclization of 3-aza-1,5-enynes and N-sulfonyl
propargylamides into pyrroles and oxazoles via sulfonyl
migration, respectively (Scheme 1, eqs 1 and 2, left).6 However,
during further investigations of N-sulfonyl propargylamides (a),
attempts to obtain 4-sulfonylmethyloxazoles (c) under the
previous optimized condition (140 °C in DMF) did not
succeed (Scheme 1, eq 2, right). The major reason is attributed
to the failure in the [3,3] rearrangement of a under thermal
conditions. To overcome this problem, we reasoned that
activation of the alkyne moiety by some transition-metal
catalysts might promote the rearrangement of a. On the other
hand, directing groups such as amide, acyloxy, and carboxylic
groups, for their potential ability to coordinate with transition-
metal catalysts, have been widely used in modern organic
synthesis.7 On the basis of these precedents, we envisioned that
the introduction of directing groups to propargylamides may
facilitate the metal-alkyne coordination. Herein, we successfully
realized this goal by introducing the acyloxy group to N-
RESULTS AND DISCUSSION
■
We initiated our studies with the screening of the conditions for
the cyclization of N-sulfonyl propargylamides 1a. Substrate 1a
was first performed under thermal and basic conditions (Table
1, entries 1−3) to investigate whether our previous reported
conditions6 were also suitable for this reaction. Unfortunately,
we did not obtain the desired product regardless which
condition was used. However, treatment of 1a with the catalyst
[Rh(COD)2]BF4 in DCE at 80 °C fortunately obtained the
desired sulfonyl-functionalized oxazole 2a just as we antici-
pated, albeit with low yield (Table 1, entry 4). The formation of
2a was confirmed by X-ray crystallography.8 Then we focused
on various transition-metal catalysts, which were frequently
used to activate triple bonds (Table 1, entries 4−8). The results
indicated that AgBF4 produced the desired oxazole in good
yield, whereas other catalysts such as PtCl2 and PPh3AuCl/
AgBF4 only have a slight improvement. Subsequently, the effect
of different silver catalysts was surveyed. Compared with other
silver salts, AgBF4 gave the best result and was chosen as the
optimal catalyst (entry 8). It is noteworthy that the yield of
oxazole 2a could be increased to 90% when the reaction was
carried out in toluene (entry 12).
With the optimized conditions in hand, we further explored
the substrate scope of the reaction, and the results are shown in
Table 2. For the R2 groups, the phenyl ring with both electron-
withdrawing and electron-donating substituents was well-
tolerated, providing the desired products in moderate to
good yields (Table 2, entries 1−9). Unfortunately, when the
aryl groups were changed to alkyl substitutions (1j, 1k), no
desired products were observed (entries 10 and 11). Mean-
Received: June 20, 2013
© XXXX American Chemical Society
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Scheme 1. Overview for Methods
Table 1. Optimization of the Reaction Conditions for the
Construction of Oxazole
Table 2. Ag-Catalyzed Cyclization of N-Tosyl
Propargylamides
a
a
R1
R2
2
yield (%)
b
entry
1
entry
catalyst
solvent
yield (%)
c
1
2
1a
1b
1c
1d
1e
1f
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
2a
2b
2c
2d
2e
2f
82
75
79
72
80
56
67
81
79
0
1
DMF
CH3CN
DCM
DCE
d
o-Me-C6H4
m-OMe-C6H4
m-Br-C6H4
m-F-C6H4
p-Me-C6H4
p-Cl-C6H4
p-F-C6H4
p-CF3-C6H4
OEt
2
DBU
e
3
3
DABCO
4
4
5
[Rh(COD)2]BF4
PtCl2
36
40
57
51
86
80
82
70
90
5
DCE
6
6
PPh3AuCl/AgBF4
[Rh(PPh3)2CO]Cl/AgBF4
AgBF4
DCE
7
1g
1h
1i
2g
2h
2i
7
DCE
8
8
DCE
9
9
AgSbF6
DCE
10
11
12
13
14
15
16
17
18
1j
2j
10
11
12
AgOTf
DCE
1k
1l
cyclopentyl
C6H5
2k
2l
0
AgNO3
DCE
o-F-C6H4
72
90
81
73
83
53
0
AgBF4
toluene
a
1m
1n
1o
1p
1q
1r
m-F-C6H4
m-OMe-C6H4
p-Br-C6H4
1-naphthyl
2-naphthyl
2-furanyl
C6H5
2m
2n
2o
2p
2q
2r
Reaction conditions: 1a (0.1 mmol), catalyst (10 mol %), solvent (1
mL), 80 °C for 10 h. Determined by HPLC. Benzamide was used as
internal standard. DMF (1 mL), 140 °C for 10 h. DBU (10 mol %),
CH3CN (1 mL), rt for 7 h. DABCO (10 mol %), DCM (1 mL), rt for
b
C6H5
c
d
C6H5
e
C6H5
7 h.
C6H5
C6H5
a
Reaction conditions: 1 (0.2 mmol), AgBF4 (10 mol %), toluene (1.5
mL), 80 °C for 10 h.
while, other functional groups such as −OMe, −F, and−-Br in
aromatic R1 groups were also compatible with this cyclization
and afforded the corresponding oxazoles in satisfactory yields
(Table 2, entries 12−15). Notably, reaction with naphthyl-
derived substrates 1p and 1q proceeded well, whereas furanyl-
derived substrate 1r gave no desired oxazole. However, when
we tried to prepare other heterocyclic motifs such as the 2-
pridyl group in R1, we failed to obtain the desired substrate.
Likewise, the scope of the sulfonyl group in the substrate was
examined under the same condition. As shown in Table 3, N-
phenylsulfonyl substrates 1s and 1t were also suitable for this
cyclization and afforded the corresponding oxazoles in 90 and
81% yield, respectively. Besides, 1u underwent the cyclization
smoothly to give the desired oxazole 2u in a moderate yield via
methylsulfonyl migration.
Moreover, oxazoles 2 can be easily transformed into the
corresponding alcohol derivatives by the hydrolysis of esters.
For example, as shown in Scheme 2, oxazole 2aa was readily
obtained in 90% yield simply by saponification of 2a, which
could undergo further transformations to construct more
valuable molecules.9
To find out whether the migration of the sulfonyl group
occurred in an intramolecular or intermolecular mode, a
crossover experiment was performed (Scheme 3). The reaction
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a
Table 3. Scope of the Sulfonyl Group for the Synthesis of Oxazoles
a
Reaction conditions: 1 (0.2 mmol), AgBF4 (10 mol %), toluene (1.5 mL), 80 °C for 10 h.
determine if some chiral transfer occurred under the standard
condition. Although much effort has been made, unfortunately,
we failed to afford the desired enantiomerically pure substrate.
On the basis of these observations, a plausible mechanism
was proposed as depicted in Scheme 4. As a first step, we
supposed that a π-complex 3 was formed between the alkyne
moiety and Ag(I) cation. Meanwhile, the acyloxy group also
coordinated with Ag(I) to facilitate subsequent transformations.
Then intramolecular nucleophilic attack of the carbonyl oxygen
on the amide via 6-endo-dig mode resulted in the formation of
intermediate 4, which collapsed into the allene intermediate
5.11 It is worth noting that 6-endo-dig cyclization of
propargylamides has been well studied by some other groups.12
Then, nucleophilic attack of the nitrogen at the allenyl carbon
followed to give a zwitterionic intermediate 6 and then
Scheme 2. Saponification of Oxazolyl Methyl Benzoate 2a
of a mixture 1:1 of 1a and 1t in the presence of a catalytic
amount of AgBF4 gave four oxazole products in nearly 4:4:1:1
ratio, which was confirmed by NMR spectroscopy.10 This result
indicated that the migration of the sulfonyl group may proceed
in both intra- and intermolecular manner. Moreover, we also
tried to synthesize enantiomerically pure propargylamides to
Scheme 3. Crossover Experiment To Probe the Possbile Pathway
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For this unique characteristic, the reaction provided an
alternative for the synthesis of vinyloxazoles.13 Since 5-
vinyloxazole 8a had already been obtained in a good yield, it
is not necessary to further screen the reaction conditions, and
we investigated the scope of the substrates directly.
Scheme 4. Proposed Mechanism for the Synthesis of
Oxazoles via Sulfonyl Migration
The allene substrates with both electron-withdrawing and
electron-donating substituents in aromatic R2 group were well-
tolerated, providing the corresponding vinyloxazoles in good
yields (Table 4, entries 1−5). In addition, furanyl-derived
substrate 7f underwent this transformation, as well, albeit with
low yield. To our delight, alkyl substitutions such as cyclopentyl
and methyl in R2 were also tolerated and gave the
corresponding oxazoles 8g and 8h in 65 and 66% yield,
respectively (Table 4, entries 6 and 7). Subsequently, the scope
of the R1 group was investigated. The results suggested that
both aryl and heterocyclic R1 substitutions were compatible
with this reaction (Table 4, entries 9−12). Notably, naphthyl-
derived substrate 7m could also participate in the cyclization to
afford the desired product 8m in 65% yield.
CONCLUSION
■
In summary, we have developed a silver(I)-catalyzed cyclization
of N-sulfonyl propargylamides for the synthesis of 4-(sulfonyl-
methyl)oxazoles via [3,3] rearrangement and highly regiose-
lective migration of the sulfonyl group. The introduction of the
acyloxy group was found to be essential for [3,3] rearrange-
ment. This strategy may provide a potential route for other
unrealized rearrangements. Moreover, the allenylamides,
generated from the corresponding propargylamides, can also
undergo the silver-catalyzed cyclization to give various 5-
vinyloxazoles. This method may find applications in the
synthesis of more valuable molecules.
arranged to oxazole 2 via sulfonyl shift in both intra- and
intermolecular manner.
Meanwhile, in the course of the synthesis of N-sulfonyl
propargylamides, we found that the alkyne moiety of the
substrate could be easily transformed into allene under basic
conditions. For example, allenylamide 7a was obtained in 85%
yield from propargylamide 1a just using Et3N as the base.
Inspired by this result, we suspected that allenylamide 7a could
also undergo the similar reaction in the presence of silver
catalyst. However, to our surprise, no 4-sulfonylmethyloxazole
product was detected. Instead, 5-vinyloxazole 8a was obtained
in 81% yield. In this transformation, the allene moiety was
proposed to be activated by the Ag(I) cation, followed by the
intramolecular nucleophilic attack of the oxygen atom at the
amide moiety (Scheme 5). The elimination of both sulfonyl
and acyloxy groups generated the final vinyloxazole product.
EXPERIMENTAL SECTION
■
General Information. Unless otherwise noted, all reactions and
manipulations were carried out under an atmosphere of argon using
standard Schlenk techniques or in an argon-filled glovebox. Solvents
were treated prior to use according to the standard methods. All
chemicals were obtained from commercial sources and were used
without further purification. Column chromatography was carried out
on silica gel (300−400 mesh) using a forced flow of eluent at 0.3−0.5
bar pressure. NMR spectra were recorded at room temperature in
CDCl3 on 400 or 500 MHz spectrometers. The chemical shifts for 1H
NMR were recorded in parts per million downfield from tetramethyl-
silane (TMS) with CDCl3 (7.26 ppm) as the internal standard. The
chemical shifts for 13C NMR were recorded in parts per million
downfield using the central peak of CDCl3 (77.16 ppm) as the internal
standard. Coupling constants (J) are reported in hertz and refer to
apparent peak multiplications.
Scheme 5. Silver(I)-Catalyzed Cyclization of Allenylamide
General Procedure for the Synthesis of N-Sulfonyl Prop-
argylamides.
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a
Table 4. Substrate Scope for the Synthesis of Vinyloxazoles
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Table 4. continued
a
Reaction conditions: 7 (0.15 mmol), AgBF4 (10 mol %), toluene (1.5 mL), 80 °C for 16−20 h.
To a solution of prop-2-yn-1-ol (10, 23.4 mL, 400 mmol) in CH2Cl2
(200 mL) at 0 °C was added p-TsOH (0.760 g, 4 mmol) followed by
slow addition of 3,4-dihydro-2H-pyran (11, 42.00 mL, 460 mmol).
After stirring at 0 °C for 5 min, the reaction was warmed to room
temperature and stirred for 3 h. The reaction was quenched with
saturated NaHCO3, and the layers were separated. The aqueous layer
was extracted with Et2O, and the combined organic layers were dried
over MgSO4, concentrated in vacuo, and purified by distillation to give
12 as a colorless oil (50 mL, 90% yield).
To a solution of 2-(prop-2-yn-1-yloxy)tetrahydro-2H-pyran 12
(1.40 g, 10.0 mmol) in THF (20 mL) at −78 °C under argon was
added n-BuLi (4.00 mL, 2.5 M in hexanes, 10.0 mmol), and the
F
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resulting solution was stirred for 40 min at −78 °C. Tosyl imine (13,
10.0 mmol) in THF (20 mL) was then added, and the reaction was
warmed to room temperature and stirred for 3 h. The reaction was
quenched with water, and the layers were separated. The aqueous layer
was extracted with Et2O, and the combined organic layers were
washed twice with brine, dried over MgSO4, filtered, and concentrated
under reduced pressure. The crude residue was purified by direct
crystallization from EtOH/pentane to yield 14 as a white or yellow
solid.
To a solution of 14 (8.00 mmol) in MeOH (80 mL) was added p-
TsOH (0.152 g, 0.8 mmol), and the reaction mixture was stirred at
room temperature for 1 h. The reaction was quenched with saturated
NaHCO3, and the resulting suspension was extracted with Et2O. The
combined organic phases were dried over MgSO4, and the solvent was
removed via rotary evaporation. The crude residue was purified by
direct crystallization from EtOH/pentane to afford 15 as a white or
yellow solid.
122.0, 82.7, 81.6, 53.5, 53.2, 21.8; HRMS (ESI-TOF) m/z calcd for
C31H23NO5NaSBr2 [M + Na]+ 701.9561, found 701.9540.
4-(3-Fluoro-N-tosylbenzamido)-4-phenylbut-2-yn-1-yl 3-fluoro-
1
benzoate (1e): Yellow solid, 0.6015 g, 43% yield, mp 69−70 °C; H
NMR (500 MHz, CDCl3) δ 7.93−7.86 (m, 1H), 7.77 (ddd, J = 9.2,
2.4, 1.5 Hz, 1H), 7.69 (d, J = 8.4 Hz, 2H), 7.52−7.41 (m, 3H), 7.33−
7.22 (m, 6H), 7.20−7.12 (m, 2H), 7.06 (tdd, J = 8.3, 2.5, 1.1 Hz, 1H),
7.01−6.94 (m, 1H), 6.42 (s, 1H), 5.03 (d, J = 1.8 Hz, 2H), 2.38 (s,
3H); 13C NMR (126 MHz, CDCl3) δ 169.5 (d, J = 2.3 Hz), 164.8 (d, J
= 2.9 Hz), 162.7 (d, J = 247.5 Hz), 162.0 (d, J = 248.3 Hz), 145.3,
137.0 (d, J = 7.1 Hz), 135.9, 135.39, 131.8 (d, J = 7.4 Hz), 130.4 (d, J
= 7.8 Hz), 129.7 (d, J = 7.8 Hz), 129.6, 128.9, 128.6, 128.5, 127.8,
125.7 (d, J = 2.9 Hz), 124.2 (d, J = 3.0 Hz), 120.6 (d, J = 21.3 Hz),
118.7 (d, J = 21.1 Hz), 116.8 (d, J = 23.1 Hz), 115.4 (d, J = 23.6 Hz),
82.6, 81.6, 53.6, 53.2, 21.7; 19F NMR (377 MHz, CDCl3) δ −112.5,
−112.6; HRMS (ESI-TOF) m/z calcd for C31H23NO5NaSF2 [M +
Na]+ 582.1163, found 582.1145.
4-(4-Methyl-N-tosylbenzamido)-4-phenylbut-2-yn-1-yl 4-methyl-
A solution of 15 (2.50 mmol) in 30 mL of toluene was treated at
−78 °C with 5.00 mL (5.00 mmol) of a 1.0 M solution of LiHMDS in
THF and stirred for 40 min at −78 °C. The resulting mixture was then
treated with acyl chloride 16 (6.00 mmol) and stirred at room
temperature for 1 h. The reaction was quenched with water, and the
layers were separated. The aqueous layer was extracted with Et2O, and
the combined organic layers were washed twice with brine, dried over
MgSO4, filtered, and concentrated under reduced pressure. The crude
residue was purified by flash chromatography over silica gel
(petroleum ether/EtOAc: 10/1) to give 1 as a white or yellow solid.
4-Phenyl-4-(N-tosylbenzamido)but-2-yn-1-yl benzoate (1a):
1
benzoate (1f): Yellow solid, 0.4689 g, 34% yield, mp 51−52 °C; H
NMR (500 MHz, CDCl3) δ 7.99 (d, J = 8.2 Hz, 2H), 7.68 (d, J = 8.3
Hz, 2H), 7.47 (dd, J = 7.0, 1.2 Hz, 2H), 7.34 (d, J = 8.1 Hz, 2H),
7.30−7.24 (m, 5H), 7.18 (d, J = 8.1 Hz, 2H), 7.02 (d, J = 7.9 Hz, 2H),
6.33 (s, 1H), 5.00 (d, J = 1.8 Hz, 2H), 2.43 (s, 3H), 2.35 (s, 3H), 2.29
(s, 3H); 13C NMR (126 MHz, CDCl3) δ 171.1, 166.0, 144.8, 144.3,
142.6, 136.2, 135.6, 132.2, 130.0, 129.39, 129.37, 129.0, 128.8, 128.5,
128.3, 128.0, 127.0, 82.5, 81.8, 54.1, 52.8, 21.8, 21.7, 21.6; HRMS
(ESI-TOF) m/z calcd for C33H29NO5NaS [M + Na]+ 574.1664, found
574.1659.
4-(4-Chloro-N-tosylbenzamido)-4-phenylbut-2-yn-1-yl 4-chloro-
benzoate (1g): Yellow solid, 0.5925 g, 40% yield, mp 142−143 °C;
1H NMR (500 MHz, CDCl3) δ 8.05−8.00 (m, 2H), 7.71−7.63 (m,
2H), 7.48−7.41 (m, 4H), 7.31−7.25 (m, 5H), 7.21 (d, J = 8.0 Hz,
2H), 7.19−7.14 (m, 2H), 6.37 (s, 1H), 4.99 (dd, J = 1.8, 0.7 Hz, 2H),
2.37 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 170.0, 165.0, 145.2,
140.1, 138.2, 135.9, 135.3, 133.5, 131.3, 130.0, 129.5, 129.0, 128.8,
128.6, 128.5, 128.2, 128.0, 127.8, 82.5, 81.6, 53.6, 53.0, 21.7; HRMS
(ESI-TOF) m/z calcd for C31H23NO5NaSCl2 [M + Na]+ 614.0572,
found 614.0570.
1
White solid, 1.0462 g, 80% yield, mp 101−102 °C; H NMR (500
MHz, CDCl3) δ 8.09−8.01 (m, 2H), 7.63 (d, J = 8.3 Hz, 2H), 7.55 (t,
J = 7.4 Hz, 1H), 7.47−7.37 (m, 4H), 7.36−7.28 (m, 3H), 7.35−7.20
(m, 3H), 7.17−7.13 (m, 4H), 6.35 (s, 1H), 4.99 (d, J = 1.4 Hz, 2H),
2.30 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 170.9, 165.9, 144.9,
136.1, 135.6, 135.0, 133.5, 131.7, 129.9, 129.6, 129.4, 128.9, 128.6,
128.5, 128.4, 128.3, 128.0, 127.8, 82.5, 81.7, 53.8, 52.9, 21.7; HRMS
(ESI-TOF) m/z calcd for C31H25NO5NaS [M + Na]+ 546.1351, found
546.1349.
4-(2-Methyl-N-tosylbenzamido)-4-phenylbut-2-yn-1-yl 2-methyl-
4-(4-Fluoro-N-tosylbenzamido)-4-phenylbut-2-yn-1-yl 4-fluoro-
benzoate (1h): Yellow solid, 0.8393 g, 60% yield, mp 46−47 °C;
1H NMR (400 MHz, CDCl3) δ 8.15−8.07 (m, 2H), 7.68 (d, J = 8.3
1
benzoate (1b): Yellow solid, 0.7171 g, 52% yield, mp 44−45 °C; H
NMR (500 MHz, CDCl3) δ 7.97 (dd, J = 8.4, 1.3 Hz, 1H), 7.60−7.55
(m, 4H), 7.44 (td, J = 7.6, 1.4 Hz, 1H), 7.35−7.27 (m, 5H), 7.20 (td, J
= 7.5, 1.4 Hz, 1H), 7.14 (d, J = 8.1 Hz, 2H), 7.04 (dd, J = 7.9, 1.3 Hz,
1H), 7.01−6.95 (m, 2H), 6.58 (s, 1H), 5.06 (t, J = 1.9 Hz, 2H), 2.63
(s, 3H), 2.34 (s, 3H), 1.96 (s, 3H); 13C NMR (126 MHz, CDCl3) δ
170.1, 166.6, 144.8, 140.6, 136.4, 136.2, 136.0, 134.3, 132.4, 131.8,
130.8, 130.22, 130.18, 129.2, 128.9, 128.7, 128.4, 128.1, 127.5, 127.3,
125.8, 124.8, 82.4, 81.4, 53.1, 52.5, 21.8, 21.6, 18.9; HRMS (ESI-TOF)
m/z calcd for C33H29NO5NaS [M + Na]+ 574.1664, found 574.1653.
4-(3-Methoxy-N-tosylbenzamido)-4-phenylbut-2-yn-1-yl 3-
methoxybenzoate (1c): Yellow solid, 0.4815 g, 33% yield, mp 43−
44 °C; 1H NMR (500 MHz, CDCl3) δ 7.72−7.64 (m, 3H), 7.61 (dd, J
= 2.6, 1.5 Hz, 1H), 7.51−7.43 (m, 2H), 7.38 (t, J = 8.0 Hz, 1H), 7.32−
7.26 (m, 3H), 7.20−7.12 (m, 4H), 7.05−7.02 (m, 1H), 6.94−6.89 (m,
1H), 6.82 (dd, J = 2.4, 1.6 Hz, 1H), 6.40 (s, 1H), 5.06 (d, J = 1.9 Hz,
2H), 3.85 (s, 3H), 3.65 (s, 3H), 2.36 (s, 3H); 13C NMR (126 MHz,
CDCl3) δ 170.7, 165.8, 159.8, 159.2, 144.9, 136.2, 136.0, 135.6, 130.9,
129.7, 129.4, 129.2, 129.0, 128.6, 128.4, 127.9, 122.4, 120.8, 120.0,
118.4, 114.5, 112.7, 82.7, 81.7, 55.6, 55.3, 54.1, 53.0, 21.7; HRMS
(ESI-TOF) m/z calcd for C33H29NO7NaS [M + Na]+ 606.1562, found
606.1542.
Hz, 2H), 7.48−7.36 (m, 4H), 7.31−7.21 (m, 5H), 7.16 (t, J = 8.7 Hz,
2H), 6.89 (t, J = 8.6 Hz, 2H), 6.37 (s, 1H), 5.00 (d, J = 1.1 Hz, 2H),
2.38 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 170.1, 166.2 (d, J =
254.8 Hz), 165.0, 164.9 (d, J = 253.4 Hz), 145.1, 136.0, 135.4, 132.6
(d, J = 9.4 Hz), 131.3 (d, J = 9.2 Hz), 129.6, 128.9, 128.6, 128.5, 127.9,
125.9 (d, J = 2.8 Hz), 115.9 (d, J = 22.1 Hz), 115.2 (d, J = 22.1 Hz),
82.6, 81.7, 53.7, 53.0, 21.8; 19F NMR (471 MHz, CDCl3) δ −104.6
(dd, J = 13.3, 7.4 Hz), −105.8 (m); HRMS (ESI-TOF) m/z calcd for
C31H23NO5NaSF2 [M + Na]+ 582.1163, found 582.1171.
4-Phenyl-4-(N-tosyl-4-(trifluoromethyl)benzamido)but-2-yn-1-yl-
4-(trifluoromethyl)benzoate (1i): White solid, 0.4617 g, 28% yield,
mp 115−116 °C; 1H NMR (500 MHz, CDCl3) δ 8.21 (d, J = 8.1 Hz,
2H), 7.75 (d, J = 8.2 Hz, 2H), 7.66 (d, J = 8.4 Hz, 2H), 7.48−7.40 (m,
4H), 7.36 (d, J = 8.2 Hz, 2H), 7.29−7.25 (m, 3H), 7.21 (d, J = 8.1 Hz,
2H), 6.45 (s, 1H), 5.05 (d, J = 1.8 Hz, 2H), 2.38 (s, 3H); 13C NMR
(126 MHz, CDCl3) δ 169.7, 164.8, 145.4, 138.4, 135.8, 135.2, 135.0,
133.2, 132.9, 132.8, 130.3 129.9, 129.8, 129.7, 129.5, 128.8, 128.7,
128.6, 128.2, 127.8, 127.0, 126.3, 125.8 (dd, J = 7.1, 3.5 Hz), 124.9
(dd, J = 6.9, 3.6 Hz), 123.7 (d, J = 272.8 Hz), 123.6 (d, J = 272.5 Hz),
82.6, 81.5, 53.4, 53.3, 21.7; 19F NMR (377 MHz, CDCl3) δ −63.7,
−63.8; HRMS (ESI-TOF) m/z calcd for C33H23NO5NaSF6 [M +
Na]+ 682.1099, found 682.1087.
4-(3-Bromo-N-tosylbenzamido)-4-phenylbut-2-yn-1-yl 3-bromo-
1
benzoate (1d): Yellow solid, 0.8688 g, 51% yield, mp 53−54 °C; H
NMR (500 MHz, CDCl3) δ 8.24 (t, J = 1.7 Hz, 1H), 8.08−7.99 (m,
1H), 7.74 (ddd, J = 8.0, 2.0, 1.0 Hz, 1H), 7.66 (d, J = 8.4 Hz, 2H),
7.51−7.43 (m, 3H), 7.37 (t, J = 7.9 Hz, 1H), 7.33−7.27 (m, 4H),
7.26−7.22 (m, 3H), 7.09 (t, J = 7.9 Hz, 1H), 6.47 (s, 1H), 5.05 (d, J =
1.8 Hz, 2H), 2.40 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 169.3,
164.6, 145.4, 136.9, 136.5, 135.9, 135.4, 134.4, 133.0, 131.6, 131.1,
130.3, 129.7, 129.5, 128.8, 128.7, 128.58, 128.56, 127.8, 126.9, 122.8,
Ethyl (4-((ethoxycarbonyl)oxy)-1-phenylbut-2-yn-1-yl)(tosyl)-
carbamate (1j): Yellow solid, 0.4365 g, 38% yield, mp 64−65 °C;
1H NMR (500 MHz, CDCl3) δ 7.89 (d, J = 8.4 Hz, 2H), 7.70−7.52
(m, 2H), 7.39−7.30 (m, 5H), 6.72 (s, 1H), 4.86 (d, J = 1.8 Hz, 2H),
4.25 (q, J = 7.1 Hz, 2H), 4.00 (qd, J = 7.1, 3.3 Hz, 2H), 2.45 (s, 3H),
1.33 (t, J = 7.1 Hz, 3H), 1.00 (t, J = 7.1 Hz, 3H); 13C NMR (126
MHz, CDCl3) δ 154.7, 151.3, 144.8, 136.6, 136.5, 129.5, 128.7, 128.4,
G
dx.doi.org/10.1021/jo401330t | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
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128.1, 127.3, 83.1, 80.2, 64.7, 63.6, 55.5, 52.2, 21.8, 14.4, 13.8; HRMS
(ESI-TOF) m/z calcd for C23H25NO7NaS [M + Na]+ 482.1249, found
482.1250.
NMR (400 MHz, CDCl3) δ 8.13 (d, J = 7.8 Hz, 2H), 7.94 (s, 1H),
7.81−7.66 (m, 5H), 7.60 (t, J = 7.3 Hz, 1H), 7.55−7.42 (m, 5H), 7.39
(d, J = 7.7 Hz, 2H), 7.31 (t, J = 7.4 Hz, 1H), 7.14 (t, J = 8.5 Hz, 4H),
6.54 (s, 1H), 5.09 (s, 2H), 2.32 (s, 3H); 13C NMR (101 MHz, CDCl3)
δ 171.0, 165.9, 144.9, 135.9, 134.9, 133.5, 133.0, 132.9, 132.7, 131.8,
129.9, 129.6, 129.4, 128.9, 128.6, 128.4, 127.9, 127.7, 127.6, 126.6,
126.4, 124.9, 82.5, 81.9, 54.0, 52.9, 21.7; HRMS (ESI-TOF) m/z calcd
for C35H27NO5NaS [M + Na]+ 596.1508, found 596.1504.
4-(Furan-2-yl)-4-(N-tosylbenzamido)but-2-yn-1-yl benzoate (1r):
Brown solid, 0.1926 g, 15% yield, mp 58−59 °C; 1H NMR (400 MHz,
CDCl3) δ 8.10−8.04 (m, 2H), 7.66 (d, J = 8.3 Hz, 2H), 7.57 (t, J = 7.4
Hz, 1H), 7.47−7.43 (m, 4H), 7.37 (t, J = 7.5 Hz, 1H), 7.26−7.15 (m,
5H), 6.43 (d, J = 3.2 Hz, 1H), 6.29 (s, 1H), 6.28 (dd, J = 3.2, 1.8 Hz,
1H), 5.02 (d, J = 1.2 Hz, 2H), 2.37 (s, 3H); 13C NMR (100 MHz,
CDCl3) δ 170.9, 165.9, 148.2, 144.8, 142.8, 136.2, 134.5, 133.5, 131.9,
129.9, 129.6, 129.3, 128.9, 128.8, 128.6, 128.21, 128.17, 127.9, 111.0,
110.9, 81.2, 80.3, 52.7, 48.6, 21.7; HRMS (ESI-TOF) m/z calcd for
C29H23NO6NaS [M + Na]+ 536.1144, found 536.1147.
4-Phenyl-4-(N-tosylcyclopentanecarboxamido)but-2-yn-1-yl-
cyclopentanecarboxylate (1k): White solid, 0.2284 g, 18% yield, mp
1
56−57 °C; H NMR (500 MHz, CDCl3) δ 7.92 (d, J = 8.3 Hz, 2H),
7.57 (d, J = 8.0 Hz, 2H), 7.40−7.29 (m, 5H), 6.82 (s, 1H), 4.81 (d, J =
1.7 Hz, 2H), 2.96 (p, J = 7.9 Hz, 1H), 2.78 (p, J = 8.0 Hz, 1H), 2.45 (s,
3H), 2.00−1.18 (m, 15H), 0.98−0.77 (m, 1H); 13C NMR (126 MHz,
CDCl3) δ 178.0, 175.9, 144.7, 137.0, 136.9, 129.7, 128.8, 128.2, 128.1,
126.7, 82.4, 81.8, 52.0, 51.6, 45.4, 43.6, 31.5, 31.0, 30.1, 26.34, 26.29,
25.9, 21.8; HRMS (ESI-TOF) m/z calcd for C29H33NO5NaS [M +
Na]+ 530.1977, found 530.1968.
4-(2-Fluorophenyl)-4-(N-tosylbenzamido)but-2-yn-1-yl benzoate
1
(1l): Yellow solid, 0.3520 g, 26% yield, mp 106−107 °C; H NMR
(400 MHz, CDCl3) δ 8.13 (d, J = 7.8 Hz, 2H), 7.93 (t, J = 7.5 Hz,
1H), 7.61 (t, J = 8.7 Hz, 3H), 7.53−7.41 (m, 5H), 7.37−7.27 (m, 3H),
7.19 (t, J = 7.6 Hz, 1H), 7.08 (d, J = 8.2 Hz, 2H), 6.96−6.79 (m, 1H),
6.35 (s, 1H), 5.15 (s, 2H), 2.33 (s, 3H); 13C NMR (100 MHz, CDCl3)
δ 171.0, 165.9, 160.8 (d, J = 249.6 Hz), 144.6, 136.2, 134.5, 133.5,
132.2 (d, J = 2.4 Hz), 132.0, 130.9, 130.8, 129.9, 129.6, 129.1, 128.9,
128.6, 128.5, 128.3, 124.2 (d, J = 3.4 Hz), 122.1 (d, J = 12.0 Hz), 115.2
(d, J = 20.6 Hz), 82.0, 81.7, 53.0, 50.4, 21.7; 19F NMR (471 MHz,
CDCl3) δ −116.5 (dd, J = 13.6, 9.6 Hz); HRMS (ESI-TOF) m/z calcd
for C31H24NO5FNaS [M + Na]+ 564.1257, found 564.1248.
4-Phenyl-4-(N-(phenylsulfonyl)benzamido)but-2-yn-1-yl ben-
1
zoate (1s): Yellow solid, 0.3822 g, 30% yield, mp 107−108 °C; H
NMR (500 MHz, CDCl3) δ 8.13−8.08 (m, 2H), 7.84−7.77 (m, 2H),
7.65−7.57 (m, 1H), 7.55−7.46 (m, 5H), 7.43−7.35 (m, 5H), 7.30−
7.25 (m, 3H), 7.23−7.19 (m, 2H), 6.39 (s, 1H), 5.03 (dd, J = 1.7, 1.3
Hz, 2H); 13C NMR (126 MHz, CDCl3) δ 171.0, 165.9, 139.1, 135.5,
135.0, 133.8, 133.6, 131.9, 130.0, 129.7, 128.90, 128.86, 128.7, 128.6,
128.5, 128.4, 128.1, 127.9, 82.4, 81.8, 54.0, 52.9; HRMS (ESI-TOF)
m/z calcd for C30H23NO5NaS [M + Na]+ 532.1195, found 532.1203.
4-(4-Fluoro-N-(phenylsulfonyl)benzamido)-4-phenylbut-2-yn-1-
yl-4-fluorobenzoate (1t): White solid, 0.7465 g, 54% yield, mp 99−
4-(3-Fluorophenyl)-4-(N-tosylbenzamido)but-2-yn-1-yl benzoate
1
(1m): Red solid, 0.6228 g, 46% yield, mp 88−89 °C; H NMR (400
MHz, CDCl3) δ 8.11 (d, J = 7.5 Hz, 2H), 7.69 (d, J = 8.2 Hz, 2H),
7.62 (t, J = 7.4 Hz, 1H), 7.49 (t, J = 7.6 Hz, 2H), 7.41−7.35 (m, 3H),
7.31−7.18 (m, 7H), 6.97 (t, J = 7.7 Hz, 1H), 6.39 (s, 1H), 5.04 (s,
2H), 2.37 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 170.8, 165.9, 162.8
(d, J = 246.8 Hz), 145.2, 138.3 (d, J = 7.3 Hz), 136.0, 134.9, 133.6,
131.8, 130.1, 130.1, 130.0, 129.6, 129.6, 128.9, 128.7, 128.4, 128.0,
123.4, 115.4 (d, J = 21.6 Hz), 115.2 (d, J = 23.7 Hz), 82.0, 81.6, 53.2,
52.8, 21.7; 19F NMR (377 MHz, CDCl3) δ −113.0; HRMS (ESI-
TOF) m/z calcd for C31H24NO5FNaS [M + Na]+ 564.1257, found
564.1252.
1
100 °C; H NMR (400 MHz, CDCl3) δ 8.17−8.05 (m, 2H), 7.87−
7.76 (m, 2H), 7.55 (t, J = 7.4 Hz, 1H), 7.46−7.42 (m, 6H), 7.28−7.26
(m, 3H), 7.21−7.10 (m, 2H), 6.89 (t, J = 8.6 Hz, 2H), 6.37 (s, 1H),
4.98 (s, 2H); 13C NMR (100 MHz, CDCl3) δ 170.0, 167.4, 164.9 (d, J
= 253.8 Hz), 164.9, 138.8, 135.2, 133.9, 132.6, 132.5, 131.3, 131.25,
131.18, 131.1, 128.9, 128.8, 128.6, 128.5, 127.9, 125.8 (d, J = 3.0 Hz),
115.9 (d, J = 22.1 Hz), 115.2 (d, J = 22.1 Hz), 82.3, 81.8, 53.8, 52.9;
19F NMR (471 MHz, CDCl3) δ −104.5 (m), −106.1 (m); HRMS
(ESI-TOF) m/z calcd for C30H21NO5F2NaS [M + Na]+ 568.1006,
found 568.1002.
4-(3-Methoxyphenyl)-4-(N-tosylbenzamido)but-2-yn-1-yl ben-
1
zoate (1n): Yellow solid, 0.4982 g, 36% yield, mp 47−48 °C; H
NMR (500 MHz, CDCl3) δ 8.14−8.07 (m, 2H), 7.77−7.71 (m, 2H),
7.66−7.55 (m, 1H), 7.50−7.47 (m, 2H), 7.39−7.32 (m, 3H), 7.22−
7.16 (m, 5H), 7.04−6.99 (m, 1H), 6.96 (s, 1H), 6.78 (dd, J = 8.2, 2.5
Hz, 1H), 6.37 (s, 1H), 5.03 (dd, J = 1.8, 0.9 Hz, 2H), 3.69 (s, 3H),
2.37 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 171.1, 165.9, 159.8,
145.0, 137.1, 136.1, 135.1, 133.6, 131.7, 130.0, 129.7, 129.6, 129.5,
129.0, 128.7, 128.5, 128.0, 120.0, 114.3, 113.3, 82.6, 81.8, 55.3, 53.8,
52.9, 21.7; HRMS (ESI-TOF) m/z calcd for C32H27NO6NaS [M +
Na]+ 576.1457, found 576.1456.
4-(N-(Methylsulfonyl)benzamido)-4-phenylbut-2-yn-1-yl ben-
1
zoate (1u): Yellow solid, 0.1074 g, 12% yield, mp 100−101 °C; H
NMR (500 MHz, CDCl3) δ 8.10 (dd, J = 8.3, 1.2 Hz, 2H), 7.64−7.54
(m, 3H), 7.50−7.42 (m, 5H), 7.33−7.27 (m, 5H), 6.22 (s, 1H), 5.10−
5.06 (m, 2H), 3.16 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 172.7,
165.9, 135.3, 134.1, 133.6, 132.5, 129.9, 129.6, 128.7, 128.5, 128.0,
82.5, 82.2, 54.7, 52.8, 43.1; HRMS (ESI-TOF) m/z calcd for
C25H21NO5NaS [M + Na]+ 470.1038, found 470.1034.
Representative Procedures for the Synthesis of 4-(Sulfonyl-
methyl)oxazoles. In a 10 mL flame-dried Schlenk tube, AgBF4 (10
mol %) and N-sulfonyl propargylamide 1 (0.2 or 0.1 mmol) were
introduced under argon and dissolved in 2 mL of dry and degassed
toluene. The resulting yellow solution was stirred at 80 °C for 10 h
and concentrated under reduced pressure. Purification by flash
chromatography on silica gel (petroleum ether/EtOAc: 10/1) afforded
the expected product.
4-(4-Bromophenyl)-4-(N-tosylbenzamido)but-2-yn-1-yl benzoate
1
(1o): Red solid, 0.4669 g, 31% yield, mp 56−57 °C; H NMR (500
MHz, CDCl3) δ 8.12−8.07 (m, 2H), 7.69−7.65 (m, 2H), 7.63−7.58
(m, 1H), 7.51−7.46 (m, 2H), 7.43−7.34 (m, 7H), 7.25−7.18 (m, 4H),
6.33 (s, 1H), 5.02 (dd, J = 1.8, 0.5 Hz, 2H), 2.36 (s, 3H); 13C NMR
(126 MHz, CDCl3) δ 170.8, 165.9, 145.2, 136.0, 134.9, 133.6, 131.9,
131.7, 130.0, 129.65, 129.56, 128.8, 128.7, 128.5, 128.1, 122.6, 82.00,
81.99, 53.3, 52.8, 21.8; HRMS (ESI-TOF) m/z calcd for
C31H24BrNO5NaS [M + Na]+ 624.0456, found 624.0441.
(2-Phenyl-4-(phenyl(tosyl)methyl)oxazol-5-yl)methyl benzoate
1
(2a): White solid, 85.8 mg, 82% yield, mp 164−165 °C; H NMR
(400 MHz, CDCl3) δ 8.10−8.02 (m, 2H), 8.00 (d, J = 7.5 Hz, 2H),
7.79 (d, J = 7.1 Hz, 2H), 7.54−7.35 (m, 8H), 7.30−7.28 (m, 3H), 7.14
(d, J = 8.0 Hz, 2H), 5.83 (s, 1H), 5.60 (d, J = 13.9 Hz, 1H), 5.27 (d, J
= 13.9 Hz, 1H), 2.33 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 166.2,
161.6, 146.3, 144.7, 134.3, 133.7, 133.4, 131.4, 131.1, 130.9, 129.9,
129.8, 129.4, 129.2, 128.9, 128.8, 128.5, 128.2, 127.0, 126.8, 68.0, 54.9,
21.7; HRMS (ESI-TOF) m/z calcd for C31H25NO5NaS [M + Na]+
546.1351, found 546.1349.
(4-(Phenyl(tosyl)methyl)-2-(o-tolyl)oxazol-5-yl)methyl 2-methyl-
benzoate (2b): White solid, 41.4 mg, 75% yield, mp 143−144 °C;
1H NMR (500 MHz, CDCl3) δ 7.98 (d, J = 8.0 Hz, 1H), 7.87 (d, J =
8.3 Hz, 1H), 7.80−7.73 (m, 2H), 7.50−7.46 (m, 2H), 7.39−7.26 (m,
7H), 7.20 (d, J = 7.7 Hz, 2H), 7.15 (d, J = 7.9 Hz, 2H), 5.84 (s, 1H),
4-(Naphthalen-1-yl)-4-(N-tosylbenzamido)but-2-yn-1-yl ben-
1
zoate (1p): White solid, 0.2983 g, 36% yield, mp 108−109 °C; H
NMR (400 MHz, CDCl3) δ 8.21 (d, J = 8.6 Hz, 1H), 8.12 (d, J = 7.7
Hz, 2H), 8.05 (d, J = 7.2 Hz, 1H), 7.82 (d, J = 8.1 Hz, 1H), 7.77 (d, J
= 8.1 Hz, 1H), 7.65−7.44 (m, 7H), 7.40−7.35 (m, 4H), 7.17 (t, J = 7.7
Hz, 2H), 7.09 (d, J = 8.1 Hz, 2H), 6.98 (s, 1H), 5.00 (s, 2H), 2.31 (s,
3H); 13C NMR (126 MHz, CDCl3) δ 171.6, 166.0, 144.8, 136.0,
135.5, 133.9, 133.5, 132.3, 130.6, 130.5, 130.0, 129.7, 129.4, 129.33,
129.30, 129.2, 128.7, 128.7, 127.9, 127.2, 125.9, 125.1, 122.7, 83.3,
81.8, 53.0, 52.1, 21.7; HRMS (ESI-TOF) m/z calcd for
C35H27NO5NaS [M + Na]+ 596.1508, found 596.1519.
4-(Naphthalen-2-yl)-4-(N-tosylbenzamido)but-2-yn-1-yl ben-
1
zoate (1q): Yellow solid, 0.2386 g, 32% yield, mp 101−102 °C; H
H
dx.doi.org/10.1021/jo401330t | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
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5.61 (d, J = 13.8 Hz, 1H), 5.24 (d, J = 13.8 Hz, 1H), 2.69 (s, 3H), 2.54
(s, 3H), 2.36 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 167.0, 161.8,
146.0, 144.7, 140.8, 138.2, 134.5, 133.3, 132.5, 131.9, 131.8, 131.5,
131.3, 131.0, 130.5, 129.9, 129.2, 129.0, 128.9, 128.8, 128.2, 126.1,
125.9, 68.3, 54.7, 22.3, 21.9, 21.7; HRMS (ESI-TOF) m/z calcd for
C33H29NO5NaS [M + Na]+ 574.1664, found 574.1665.
1.5 Hz, 2H), 7.50−7.42 (m, 2H), 7.32−7.26 (m, 3H), 7.18−7.11 (m,
5H), 7.10−7.04 (m, 2H), 5.78 (s, 1H), 5.61 (d, J = 13.9 Hz, 1H), 5.27
(d, J = 13.9 Hz, 1H), 2.37 (s, 3H); 13C NMR (126 MHz, CDCl3) δ
166.1 (d, J = 254.7 Hz), 165.3, 164.5 (d, J = 251.9 Hz), 160.9, 146.4,
144.8, 134.4, 133.9, 132.6, 132.5, 131.4, 131.1, 129.8, 129.23, 129.16,
129.13, 129.06, 129.0, 128.4, 128.3, 125.8 (d, J = 2.9 Hz), 125.4, 123.4
(d, J = 3.1 Hz), 116.1 (d, J = 22.2 Hz), 115.8 (d, J = 22.1 Hz), 68.1,
55.1, 21.8; 19F NMR (377 MHz, CDCl3) δ −105.2, −109.0; HRMS
(ESI-TOF) m/z calcd for C31H23NO5NaSF2 [M + Na]+ 582.1163,
found 582.1162.
(4-(Phenyl(tosyl)methyl)-2-(4-(trifluoromethyl)phenyl)oxazol-5-
yl)-methyl-4-(trifluoromethyl)benzoate (2i): White solid, 52.6 mg,
79% yield, mp 128−129 °C; 1H NMR (500 MHz, CDCl3) δ 8.17 (d, J
= 8.1 Hz, 2H), 8.13 (d, J = 8.2 Hz, 2H), 7.75−7.70 (m, 4H), 7.68 (d, J
= 8.3 Hz, 2H), 7.47 (d, J = 8.2 Hz, 2H), 7.34−7.27 (m, 3H), 7.17 (d, J
= 8.0 Hz, 2H), 5.79 (s, 1H), 5.71 (d, J = 13.9 Hz, 1H), 5.38 (d, J =
13.9 Hz, 1H), 2.39 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 165.2,
160.4, 146.9, 145.0, 135.5, 135.2, 135.0, 134.7, 134.4, 134.3, 133.0,
132.8, 132.7, 132.6, 131.4, 131.0, 130.4, 130.1, 129.9, 129.3, 129.2,
128.4, 127.2, 126.0, 125.93, 125.90, 125.7, 125.63, 125.60, 123.9 (d, J =
272.5 Hz), 123.6 (d, J = 272.7 Hz), 68.2, 55.4, 21.8; 19F NMR (377
MHz, CDCl3) δ −63.5, −63.8; HRMS (ESI-TOF) m/z calcd for
C33H23NO5NaSF6 [M + Na]+ 682.1099, found 682.1083.
(2-(3-Methoxyphenyl)-4-(phenyl(tosyl)methyl)oxazol-5-yl)methyl
3-methoxybenzoate (2c): White solid, 46.1 mg, 79% yield, mp 50−51
1
°C; H NMR (500 MHz, CDCl3) δ 7.78−7.72 (m, 2H), 7.67−7.62
(m, 1H), 7.61−7.58 (m, 1H), 7.57 (dd, J = 2.5, 1.5 Hz, 1H), 7.52 (dd,
J = 2.6, 1.5 Hz, 1H), 7.50−7.45 (m, 2H), 7.36 (t, J = 8.0 Hz, 1H),
7.33−7.26 (m, 4H), 7.15 (d, J = 7.9 Hz, 2H), 7.08 (ddd, J = 8.2, 2.7,
1.0 Hz, 1H), 7.00 (ddd, J = 8.3, 2.6, 0.9 Hz, 1H), 5.78 (s, 1H), 5.59 (d,
J = 13.9 Hz, 1H), 5.27 (d, J = 13.9 Hz, 1H), 3.88 (s, 3H), 3.81 (s, 3H),
2.36 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 166.2, 161.5, 160.6,
159.8, 146.4, 144.8, 134.4, 133.8, 131.5, 131.2, 130.8, 130.0, 129.9,
129.6, 129.2, 129.0, 128.3, 122.4, 120.0, 119.4, 117.1, 114.4, 112.0,
68.2, 55.6, 55.2, 21.7; HRMS (ESI-TOF) m/z calcd for
C33H29NO7NaS [M + Na]+ 606.1562, found 606.1550.
(2-(3-Bromophenyl)-4-(phenyl(tosyl)methyl)oxazol-5-yl)methyl
3-bromobenzoate (2d): Yellow solid, 49.2 mg, 72% yield, mp 77−78
°C; 1H NMR (500 MHz, CDCl3) δ 8.18 (t, J = 1.7 Hz, 1H), 8.13 (t, J
= 1.7 Hz, 1H), 8.00−7.96 (m, 1H), 7.95−7.90 (m, 1H), 7.76−7.70 (m,
2H), 7.66 (ddd, J = 8.0, 2.0, 1.1 Hz, 1H), 7.58 (ddd, J = 8.0, 2.0, 1.0
Hz, 1H), 7.49−7.44 (m, 2H), 7.34−7.26 (m, 5H), 7.17 (d, J = 7.9 Hz,
2H), 5.77 (s, 1H), 5.62 (d, J = 13.9 Hz, 1H), 5.29 (d, J = 13.9 Hz, 1H),
2.38 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 165.0, 160.3, 146.6,
144.9, 136.5, 134.3, 134.2, 134.0, 132.9, 131.4, 131.0, 130.4, 130.2,
129.9, 129.8, 129.3, 129.1, 128.8, 128.6, 128.4, 125.4, 123.0, 122.7,
68.1, 55.3, 21.8; HRMS (ESI-TOF) m/z calcd for C31H23NO5NaSBr2
[M + Na]+ 701.9561, found 701.9552.
(4-((2-Fluorophenyl)(tosyl)methyl)-2-phenyloxazol-5-yl)methyl
1
benzoate (2l): White solid, 77.0 mg, 72% yield, mp 66−67 °C; H
NMR (500 MHz, CDCl3) δ 8.59−8.48 (m, 1H), 8.12−7.99 (m, 4H),
7.56−7.52 (m, 3H), 7.48−7.38 (m, 5H), 7.30 (d, J = 7.4 Hz, 1H), 7.21
(t, J = 7.6 Hz, 1H), 7.16 (d, J = 8.1 Hz, 2H), 6.92 (t, J = 9.1 Hz, 1H),
6.20 (s, 1H), 5.54 (d, J = 13.9 Hz, 1H), 5.36 (d, J = 13.9 Hz, 1H), 2.35
(s, 3H); 13C NMR (126 MHz, CDCl3) δ 166.1, 161.7, 161.0 (d, J =
249.4 Hz), 146.8, 145.0, 134.5, 133.4, 133.3, 132.6, 131.0, 130.8 (d, J =
8.5 Hz), 130.0, 129.6, 129.6, 129.4, 128.8, 128.5, 127.0, 126.9, 124.1
(d, J = 3.4 Hz), 118.7 (d, J = 13.0 Hz), 115.0 (d, J = 22.7 Hz), 58.8 (d,
J = 4.1 Hz), 55.2, 21.7; 19F NMR (471 MHz, CDCl3) δ −116.8 (dd, J
= 15.4, 6.9 Hz); HRMS (ESI-TOF) m/z calcd for C31H24NO5FNaS
[M + Na]+ 564.1257, found 564.1250.
(2-(3-Fluorophenyl)-4-(phenyl(tosyl)methyl)oxazol-5-yl)methyl 3-
fluorobenzoate (2e): Yellow solid, 48.9 mg, 80% yield, mp 66−67 °C;
1H NMR (500 MHz, CDCl3) δ 7.87−7.83 (m, 1H), 7.83−7.78 (m,
1H), 7.74 (ddd, J = 8.1, 3.4, 1.6 Hz, 3H), 7.68 (ddd, J = 9.2, 2.6, 1.5
Hz, 1H), 7.50−7.35 (m, 4H), 7.33−7.21 (m, 4H), 7.19−7.12 (m, 3H),
5.79 (s, 1H), 5.64 (d, J = 13.9 Hz, 1H), 5.30 (d, J = 13.9 Hz, 1H), 2.38
(s, 3H); 13C NMR (126 MHz, CDCl3) δ 165.2 (d, J = 2.9 Hz), 163.0
(d, J = 246.7 Hz), 162.6 (d, J = 247.6 Hz), 160.6 (d, J = 3.4 Hz), 146.6,
144.9, 134.3, 134.2, 131.6 (d, J = 7.6 Hz), 131.4, 131.0, 130.6 (d, J =
8.1 Hz), 130.2 (d, J = 7.8 Hz), 129.9, 129.3, 129.1, 128.9 (d, J = 8.5
Hz), 128.4, 125.7 (d, J = 2.9 Hz), 122.6, 120.6 (d, J = 21.3 Hz), 118.0
(d, J = 21.3 Hz), 116.8 (d, J = 23.2 Hz), 113.9 (d, J = 24.1 Hz), 68.1,
55.3, 21.7; 19F NMR (377 MHz, CDCl3) δ −112.58, −112.59; HRMS
(ESI-TOF) m/z calcd for C31H23NO5NaSF2 [M + Na]+ 582.1163,
found 582.1154.
(4-((3-Fluorophenyl)(tosyl)methyl)-2-phenyloxazol-5-yl)methyl
1
benzoate (2m): Red solid, 98.9 mg, 90% yield, mp 123−124 °C; H
NMR (500 MHz, CDCl3) δ 8.07−8.03 (m, 2H), 8.02−7.98 (m, 2H),
7.68−7.63 (m, 1H), 7.55−7.38 (m, 9H), 7.26−7.22 (m, 1H), 7.17 (d, J
= 8.0 Hz, 2H), 7.05−6.98 (m, 1H), 5.85 (s, 1H), 5.60 (d, J = 13.9 Hz,
1H), 5.24 (d, J = 13.9 Hz, 1H), 2.36 (s, 3H); 13C NMR (126 MHz,
CDCl3) δ 166.3, 162.4 (d, J = 245.9 Hz), 161.8, 146.6, 145.0, 134.2,
133.5, 133.4 (d, J = 8.2 Hz), 133.3, 131.0, 129.9, 129.8, 129.64, 129.58,
129.5, 129.3, 128.8, 128.6, 127.3 (d, J = 2.7 Hz), 126.93, 126.91, 118.5
(d, J = 23.2 Hz), 116.0 (d, J = 21.0 Hz), 67.6, 54.9, 21.7; 19F NMR
(471 MHz, CDCl3) δ −112.5 (dd, J = 15.4, 9.0 Hz); HRMS (ESI-
TOF) m/z calcd for C31H24NO5FNaS [M + Na]+ 564.1257, found
564.1274.
(4-(Phenyl(tosyl)methyl)-2-(p-tolyl)oxazol-5-yl)methyl 4-methyl-
benzoate (2f): White solid, 30.7 mg, 56% yield, mp 157−158 °C;
1H NMR (500 MHz, CDCl3) δ 7.95−7.91 (m, 2H), 7.90−7.85 (m,
(4-((3-Methoxyphenyl)(tosyl)methyl)-2-phenyloxazol-5-yl)methyl
2H), 7.76 (dd, J = 7.7, 1.8 Hz, 2H), 7.51−7.45 (m, 2H), 7.31−7.23
(m, 5H), 7.19 (d, J = 8.0 Hz, 2H), 7.14 (d, J = 8.0 Hz, 2H), 5.78 (s,
1H), 5.55 (d, J = 13.9 Hz, 1H), 5.23 (d, J = 13.9 Hz, 1H), 2.40 (s, 3H),
2.37 (s, 3H), 2.36 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 166.4,
161.9, 146.2, 144.7, 144.2, 141.3, 134.6, 133.6, 131.5, 131.2, 130.0,
129.9, 129.5, 129.3, 129.2, 129.0, 128.3, 126.9, 124.5, 68.19, 54.9,
21.81, 21.75, 21.7; HRMS (ESI-TOF) m/z calcd for C33H29NO5NaS
[M + Na]+ 574.1664, found 574.1672.
1
benzoate (2n): Yellow solid, 89.8 mg, 81% yield, mp 61−62 °C; H
NMR (500 MHz, CDCl3) δ 8.06−8.02 (m, 2H), 8.00 (dt, J = 8.5, 1.5
Hz, 2H), 7.55−7.50 (m, 3H), 7.46−7.43 (m, 4H), 7.40 (dd, J = 8.0,
7.5 Hz, 2H), 7.27 (dd, J = 6.6, 1.1 Hz, 1H), 7.20−7.14 (m, 3H), 6.86
(ddd, J = 8.2, 2.6, 0.9 Hz, 1H), 5.78 (s, 1H), 5.58 (d, J = 13.9 Hz, 1H),
5.28 (d, J = 13.9 Hz, 1H), 3.76 (s, 3H), 2.36 (s, 3H); 13C NMR (126
MHz, CDCl3) δ 166.2, 161.6, 159.4, 146.4, 144.8, 134.5, 133.8, 133.5,
132.4, 130.9, 129.9, 129.5, 129.2, 128.8, 128.5, 127.1, 126.8, 123.9,
116.4, 115.4, 68.1, 55.3, 55.0, 21.7; HRMS (ESI-TOF) m/z calcd for
C32H27NO6NaS [M + Na]+ 576.1457, found 576.1446.
(2-(4-Chlorophenyl)-4-(phenyl(tosyl)methyl)oxazol-5-yl)methyl
4-chlorobenzoate (2g): White solid, 40.5 mg, 67% yield, mp 111−112
1
°C; H NMR (500 MHz, CDCl3) δ 8.02−7.97 (m, 2H), 7.96−7.90
(m, 2H), 7.74−7.70 (m, 2H), 7.49−7.41 (m, 4H), 7.40−7.35 (m, 2H),
7.32−7.26 (m, 3H), 7.16 (d, J = 8.0 Hz, 2H), 5.77 (s, 1H), 5.62 (d, J =
13.9 Hz, 1H), 5.28 (d, J = 13.9 Hz, 1H), 2.38 (s, 3H); 13C NMR (126
MHz, CDCl3) δ 165.5, 160.9, 146.5, 144.9, 140.1, 137.2, 134.4, 134.0,
131.4, 131.4, 131.1, 129.9, 129.3, 129.2, 129.1, 129.0, 128.4, 128.2,
128.0, 125.5, 68.2, 55.2, 21.8; HRMS (ESI-TOF) m/z calcd for
C31H23NO5NaSCl2 [M + Na]+ 614.0572, found 614.0574.
(2-(4-Fluorophenyl)-4-(phenyl(tosyl)methyl)oxazol-5-yl)methyl 4-
fluorobenzoate (2h): White solid, 88.9 mg, 81% yield, mp 61−62 °C;
1H NMR (500 MHz, CDCl3) δ 8.09−7.98 (m, 4H), 7.74 (dd, J = 8.0,
(4-((4-Bromophenyl)(tosyl)methyl)-2-phenyloxazol-5-yl)methyl
benzoate (2o): Yellow solid, 43.7 mg, 73% yield, mp 155−156 °C; 1H
NMR (500 MHz, CDCl3) δ 8.06−8.02 (m, 2H), 8.01−7.96 (m, 2H),
7.70−7.62 (m, 2H), 7.56−7.52 (m, 1H), 7.52−7.49 (m, 2H), 7.47−
7.38 (m, 7H), 7.19 (d, J = 8.0 Hz, 2H), 5.82 (s, 1H), 5.60 (d, J = 13.9
Hz, 1H), 5.22 (d, J = 13.9 Hz, 1H), 2.38 (s, 3H); 13C NMR (126
MHz, CDCl3) δ 166.3, 161.8, 146.6, 145.0, 134.2, 133.6, 133.3, 133.2,
131.5, 131.0, 130.2, 129.9, 129.8, 129.5, 129.4, 128.9, 128.6, 127.0,
126.9, 123.6, 67.4, 54.9, 21.8; HRMS (ESI-TOF) m/z calcd for
C31H24BrNO5NaS [M + Na]+ 624.0456, found 624.0444.
I
dx.doi.org/10.1021/jo401330t | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
(4-(Naphthalen-1-yl(tosyl)methyl)-2-phenyloxazol-5-yl)methyl
General Procedures for the Synthesis of N-Sulfonyl Allenyl-
amides. GP 1: To a solution of 1 (0.40 mmol) in THF (5 mL) was
added Et3N (0.20 mL, 1.20 mmol), and the reaction mixture was
stirred at room temperature for 3 h. The reaction was then quenched
with water, and the resulting suspension was extracted with Et2O. The
combined organic phases were dried over MgSO4, and the solvent was
removed via rotary evaporation. The crude residue was purified by
flash chromatography over silica gel (petroleum ether/EtOAc: 10/1)
to give 7 as a white or yellow solid.
1
benzoate (2p): Yellow solid, 71.2 mg, 83% yield, mp 63−64 °C; H
NMR (500 MHz, CDCl3) δ 8.59 (dd, J = 7.4, 1.1 Hz, 1H), 8.14 (d, J =
8.4 Hz, 1H), 8.04−8.01 (m, 2H), 7.93−7.88 (m, 2H), 7.79−7.71 (m,
2H), 7.46 (t, J = 7.8 Hz, 4H), 7.42−7.31 (m, 7H), 6.96 (d, J = 7.9 Hz,
2H), 6.76 (s, 1H), 5.53 (d, J = 13.9 Hz, 1H), 5.37 (d, J = 13.9 Hz, 1H),
2.19 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 166.4, 161.6, 146.6,
144.6, 134.7, 134.2, 133.8, 133.4, 132.2, 131.0, 130.7, 130.0, 129.8,
129.7, 129.5, 129.1, 129.0, 128.8, 128.5, 127.1, 127.0, 126.9, 126.8,
125.5, 125.2, 122.9, 61.8, 55.1, 21.6; HRMS (ESI-TOF) m/z calcd for
C35H27NO5NaS [M + Na]+ 596.1508, found 596.1516.
GP 2: A solution of 15 (2.00 mmol) in 30 mL of THF was treated
at −78 °C with 4.00 mL (4.00 mmol) of a 1.0 M solution of LiHMDS
in THF and stirred for 40 min at −78 °C. The resulting mixture was
then treated with chloride 16 (6.00 mmol) and stirred at room
temperature for 3 h. Subsequently, to the dark resulting solution was
added Et3N (1.00 mL, 6.00 mmol) and stirred at room temperature for
1−2 h. The reaction was quenched with water, and the layers were
separated. The aqueous layer was extracted with Et2O, and the
combined organic layers were washed twice with brine, dried over
MgSO4, filtered, and concentrated under reduced pressure. The crude
residue was purified by flash chromatography over silica gel
(petroleum ether/EtOAc: 10/1) to give 7 as a white or yellow solid.
4-Phenyl-4-(N-tosylbenzamido)buta-2,3-dien-1-yl benzoate (7a).
By following GP 1 (0.2 mmol), the compound was obtained as a
yellow solid: 99.1 mg, 90% yield, mp 71−72 °C; 1H NMR (500 MHz,
CDCl3) δ 8.05−8.02 (m, 2H), 8.00−7.96 (m, 2H), 7.59−7.55 (m,
1H), 7.53−7.49 (m, 2H), 7.47−7.41 (m, 4H), 7.39−7.28 (m, 6H),
7.21−7.14 (m, 2H), 5.83 (t, J = 6.7 Hz, 1H), 4.45 (qd, J = 12.6, 6.8 Hz,
2H), 2.40 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 207.7, 170.3,
166.1, 145.3, 135.4, 134.2, 133.8, 133.5, 131.94, 129.88, 129.8, 129.7,
129.4, 128.9, 128.6, 128.2, 127.8, 126.0, 114.0, 96.2, 60.6, 21.8; HRMS
(ESI-TOF) m/z calcd for C31H26NO5S [M + H]+ 524.1532, found
524.1535.
(4-(Naphthalen-2-yl(tosyl)methyl)-2-phenyloxazol-5-yl)methyl
1
benzoate (2q): Yellow solid, 20.2 mg, 53% yield, mp 81−82 °C; H
NMR (500 MHz, CDCl3) δ 8.19 (d, J = 1.3 Hz, 1H), 8.11−8.05 (m,
2H), 8.02−7.97 (m, 2H), 7.93 (dd, J = 8.6, 1.8 Hz, 1H), 7.82−7.75
(m, 3H), 7.55−7.49 (m, 3H), 7.48−7.43 (m, 5H), 7.41−7.36 (m, 2H),
7.11 (d, J = 8.0 Hz, 2H), 5.97 (s, 1H), 5.62 (d, J = 13.9 Hz, 1H), 5.31
(d, J = 13.9 Hz, 1H), 2.33 (s, 3H); 13C NMR (126 MHz, CDCl3) δ
166.3, 161.7, 146.4, 144.8, 134.5, 134.0, 133.5, 133.4, 133.1, 131.4,
131.0, 130.0, 129.9, 129.6, 129.3, 128.9, 128.7, 128.6, 128.4, 127.9,
127.7, 127.1, 127.0, 126.7, 126.2, 68.3, 55.1, 21.7; HRMS (ESI-TOF)
m/z calcd for C35H27NO5NaS [M + Na]+ 596.1508, found 596.1525.
(2-Phenyl-4-(phenyl(phenylsulfonyl)methyl)oxazol-5-yl)methyl
1
benzoate (2s): White solid, 47.7 mg, 90% yield, mp 167−168 °C; H
NMR (500 MHz, CDCl3) δ 8.08−8.03 (m, 2H), 8.00 (dt, J = 8.5, 1.5
Hz, 2H), 7.78−7.74 (m, 2H), 7.64−7.59 (m, 2H), 7.56−7.50 (m, 2H),
7.47−7.43 (m, 3H), 7.42−7.34 (m, 4H), 7.31−7.25 (m, 3H), 5.84 (s,
1H), 5.61 (d, J = 13.9 Hz, 1H), 5.27 (d, J = 13.9 Hz, 1H); 13C NMR
(126 MHz, CDCl3) δ 166.3, 161.7, 146.5, 137.4, 133.8, 133.6, 133.5,
131.5, 131.03, 130.97, 130.0, 129.9, 129.5, 129.0, 128.8, 128.5, 128.3,
127.1, 126.9, 68.2, 55.0; HRMS (ESI-TOF) m/z calcd for
C30H23NO5NaS [M + Na]+ 532.1195, found 532.1191.
(2-(4-Fluorophenyl)-4-(phenyl(phenylsulfonyl)methyl)oxazol-5-
yl)methyl-4-fluorobenzoate (2t): White solid, 88.5 mg, 81% yield, mp
69−70 °C; 1H NMR (500 MHz, CDCl3) δ 8.08−7.99 (m, 4H), 7.74−
7.69 (m, 2H), 7.63−7.59 (m, 2H), 7.58−7.52 (m, 1H), 7.40−7.35 (m,
2H), 7.32−7.24 (m, 3H), 7.18−7.11 (m, 2H), 7.10−7.04 (m, 2H),
5.81 (s, 1H), 5.62 (d, J = 13.9 Hz, 1H), 5.27 (d, J = 13.9 Hz, 1H); 13C
NMR (126 MHz, CDCl3) δ 166.2 (d, J = 255.0 Hz), 165.4, 164.6 (d, J
= 251.9 Hz), 161.0, 146.5, 137.3, 133.8, 133.7, 132.6, 132.5, 131.4,
131.0, 129.9, 129.15, 129.13, 129.08, 128.6, 128.4, 125.8 (d, J = 2.8
Hz), 123.4 (d, J = 3.1 Hz), 116.1 (d, J = 22.2 Hz), 115.8 (d, J = 22.0
Hz), 68.2, 55.1; 19F NMR (471 MHz, CDCl3) δ −104.2 to −105.2
(m), −108.2 to −108.9 (m); HRMS (ESI-TOF) m/z calcd for
C30H21NO5F2NaS [M + Na]+ 568.1006, found 568.1023.
4-(3-Bromo-N-tosylbenzamido)-4-phenylbuta-2,3-dien-1-yl 3-
bromobenzoate (7b). By following GP 1 (0.3 mmol), the compound
was obtained as a yellow solid: 125.4 mg, 70% yield, mp 75−76 °C; 1H
NMR (500 MHz, CDCl3) δ 8.11 (t, J = 1.7 Hz, 1H), 8.04−7.98 (m,
2H), 7.96−7.88 (m, 1H), 7.69 (ddd, J = 8.0, 2.0, 1.1 Hz, 1H), 7.59 (t, J
= 1.7 Hz, 1H), 7.47−7.41 (m, 3H), 7.38−7.33 (m, 3H), 7.33−7.28 (m,
4H), 7.02 (t, J = 7.9 Hz, 1H), 5.92 (t, J = 6.6 Hz, 1H), 4.61 (qd, J =
12.6, 6.7 Hz, 2H), 2.41 (s, 3H); 13C NMR (126 MHz, CDCl3) δ
207.7, 168.6, 164.8, 145.6, 136.4, 136.0, 135.1, 134.7, 133.3, 132.8,
131.5, 131.0, 130.2, 129.8, 129.7, 129.4, 129.0, 128.8, 128.4, 126.0,
125.9, 122.6, 122.2, 113.6, 96.1, 60.9, 21.8; HRMS (ESI-TOF) m/z
calcd for C31H23NO5NaSBr2 [M + Na]+ 701.9561, found 701.9580.
4-(3-Methoxy-N-tosylbenzamido)-4-phenylbuta-2,3-dien-1-yl 3-
methoxybenzoate (7c). By following GP 2 (2.0 mmol), the
compound was obtained as a yellow solid: 212.3 mg, 20% yield, mp
54−55 °C; 1H NMR (500 MHz, CDCl3) δ 8.10−7.99 (m, 2H), 7.61−
7.55 (m, 3H), 7.47 (dd, J = 2.5, 1.5 Hz, 1H), 7.42−7.37 (m, 2H),
7.35−7.29 (m, 4H), 7.12−7.04 (m, 3H), 6.97−6.92 (m, 1H), 6.86
(ddd, J = 7.9, 2.6, 1.4 Hz, 1H), 5.81 (t, J = 6.5 Hz, 1H), 4.45 (qd, J =
12.6, 6.6 Hz, 2H), 3.76 (s, 3H), 3.39 (s, 3H), 2.40 (s, 3H); 13C NMR
(126 MHz, CDCl3) δ 207.5, 170.1, 166.0, 159.8, 159.1, 145.4, 135.3,
135.2, 133.9, 130.9, 129.9, 129.6, 129.4, 129.3, 128.9, 128.6, 126.1,
122.26, 120.28, 120.2, 119.0, 114.12, 114.09, 111.9, 96.3, 60.6, 55.5,
55.1, 21.8; HRMS (ESI-TOF) m/z calcd for C33H29NO7NaS [M +
Na]+ 606.1562, found 606.1567.
4-(4-Methyl-N-tosylbenzamido)-4-phenylbuta-2,3-dien-1-yl 4-
methylbenzoate (7d). By following GP 1 (0.3 mmol), the compound
was obtained as a yellow solid: 101.0 mg, 62% yield, mp 111−112 °C;
1H NMR (500 MHz, CDCl3) δ 8.07−8.00 (m, 2H), 7.90−7.81 (m,
2H), 7.60−7.50 (m, 2H), 7.41−7.34 (m, 4H), 7.32−7.26 (m, 3H),
7.23−7.19 (m, 2H), 6.95 (dd, J = 8.5, 0.5 Hz, 2H), 5.81 (t, J = 6.7 Hz,
1H), 4.42 (qd, J = 12.6, 6.7 Hz, 2H), 2.39 (s, 3H), 2.38 (s, 3H), 2.22
(s, 3H); 13C NMR (126 MHz, CDCl3) δ 207.7, 170.3, 166.1, 145.1,
144.2, 142.7, 135.4, 133.8, 131.1, 129.8, 129.3, 129.2, 128.81, 128.78,
128.5, 128.0, 126.9, 126.0, 114.1, 96.2, 60.4, 21.7, 21.5; HRMS (ESI-
TOF) m/z calcd for C33H29NO5NaS [M + Na]+ 574.1664, found
574.1649.
(4-((Methylsulfonyl)(phenyl)methyl)-2-phenyloxazol-5-yl)methyl
1
benzoate (2u): Yellow solid, 13.3 mg, 64% yield, mp 63−64 °C; H
NMR (500 MHz, CDCl3) δ 8.12 − 8.08 (m, 2H), 8.00−7.96 (m, 2H),
7.96−7.91 (m, 2H), 7.56−7.51 (m, 1H), 7.50−7.46 (m, 3H), 7.43−
7.37 (m, 5H), 5.70 (s, 1H), 5.64 (d, J = 13.9 Hz, 1H), 5.37 (d, J = 13.9
Hz, 1H), 2.99 (d, J = 0.5 Hz, 3H); 13C NMR (126 MHz, CDCl3) δ
166.2, 162.0, 146.4, 134.0, 133.5, 131.8, 131.2, 130.7, 130.0, 129.5,
129.3, 129.0, 128.9, 128.6, 126.9, 67.0, 55.2, 38.2; HRMS (ESI-TOF)
m/z calcd for C25H21NO5NaS [M + Na]+ 470.1038, found 470.1034.
(2-Phenyl-4-(phenyl(tosyl)methyl)oxazol-5-yl)methanol (2aa).
To a solution of 2a (0.20 mmol) in MeOH (15 mL) was added 5%
NaOH (aq, 1.50 mL), and the reaction mixture was stirred at room
temperature for 1.5 h. The reaction was washed with water, and the
resulting suspension was extracted with Et2O. The combined organic
phases were dried over MgSO4, and the solvent was removed via
rotary evaporation. The crude residue was purified by direct
crystallization from EtOH/pentane to afford 2aa as a white solid
(75.5 mg, 90% yield, mp 129−130 °C): 1H NMR (400 MHz, CDCl3)
δ 8.02−7.95 (m, 2H), 7.72−7.63 (m, 2H), 7.48−7.40 (m, 3H), 7.37
(d, J = 8.3 Hz, 2H), 7.33−7.26 (m, 3H), 7.14 (d, J = 8.0 Hz, 2H), 5.49
(s, 1H), 4.82 (q, J = 14.3 Hz, 2H), 3.08 (s, 1H), 2.38 (s, 3H); 13C
NMR (126 MHz, CDCl3) δ 160.8, 150.9, 145.1, 133.5, 131.5, 130.9,
130.7, 130.6, 129.9, 129.2, 129.1, 128.8, 128.3, 127.2, 126.7, 69.0, 55.0,
21.8; HRMS (ESI-TOF) m/z calcd for C24H21NO4NaS [M + Na]+
442.1089, found 442.1090.
J
dx.doi.org/10.1021/jo401330t | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
4-(4-Fluoro-N-tosylbenzamido)-4-phenylbuta-2,3-dien-1-yl 4-
fluorobenzoate (7e). By following GP 1 (0.4 mmol), the compound
was obtained as a white solid: 114.0 mg, 50% yield, mp 106−107 °C;
1H NMR (500 MHz, CDCl3) δ 8.05−7.97 (m, 4H), 7.53−7.49 (m,
8.6 Hz), 116.4 (d, J = 21.8 Hz), 107.5, 94.0, 60.6, 21.7; 19F NMR (377
MHz, CDCl3) δ −112.0; HRMS (ESI-TOF) m/z calcd for
C31H24NO5FNaS [M + Na]+ 564.1257, found 564.1251.
4-(4-Bromophenyl)-4-(N-tosylbenzamido)buta-2,3-dien-1-yl ben-
zoate (7k). By following GP 1 (0.3 mmol), the compound was
2H), 7.47 (d, J = 7.6 Hz, 2H), 7.36 (t, J = 7.6 Hz, 2H), 7.32−7.28 (m,
3H), 7.09 (t, J = 8.5 Hz, 2H), 6.85 (t, J = 8.5 Hz, 2H), 5.86 (t, J = 6.5
Hz, 1H), 4.70−4.46 (m, 2H), 2.40 (s, 3H); 13C NMR (126 MHz,
CDCl3) δ 207.5, 169.1, 166.1 (d, J = 254.8 Hz), 165.1, 164.8 (d, J =
253.8 Hz), 145.4, 135.3, 133.5, 132.4 (d, J = 9.4 Hz), 130.5 (d, J = 9.0
Hz), 130.2 (d, J = 3.0 Hz), 129.8, 129.3, 128.9, 128.7, 125.9, 125.8,
115.8 (d, J = 22.1 Hz), 115.4 (d, J = 22.0 Hz), 113.9, 96.2, 60.6, 21.8;
19F NMR (377 MHz, CDCl3) δ −104.7, −106.0; HRMS (ESI-TOF)
1
obtained as a yellow solid: 97.3 mg, 54% yield, mp 61−62 °C; H
NMR (500 MHz, CDCl3) δ 8.02 (d, J = 8.4 Hz, 2H), 7.99−7.94 (m,
2H), 7.60−7.54 (m, 1H), 7.52−7.47 (m, 2H), 7.45−7.38 (m, 6H),
7.37−7.32 (m, 1H), 7.29 (d, J = 8.0 Hz, 2H), 7.22−7.16 (m, 2H), 5.80
(t, J = 6.6 Hz, 1H), 4.56−4.32 (m, 2H), 2.39 (s, 3H); 13C NMR (126
MHz, CDCl3) δ 207.4, 170.1, 166.0, 145.5, 135.2, 133.9, 133.5, 133.0,
132.1, 132.0, 129.81, 129.78, 129.5, 129.4, 128.6, 128.2, 127.7, 127.6,
122.7, 113.3, 96.7, 60.3, 21.8; HRMS (ESI-TOF) m/z calcd for
C31H24NO5BrNaS [M + Na]+ 624.0456, found 624.0465.
m/z calcd for C31H23NO5F2NaS [M + Na]+ 582.1163, found
582.1150.
4-(Furan-2-yl)-4-(N-tosylbenzamido)buta-2,3-dien-1-yl benzoate
4-Phenyl-4-(N-tosylfuran-2-carboxamido)buta-2,3-dien-1-yl
furan-2-carboxylate (7f). By following GP 2 (2.0 mmol), the
compound was obtained as a white solid: 376.0 mg, 38% yield, mp
(7l). By following GP 2 (4.0 mmol), the compound was obtained as a
1
yellow solid: 440.1 mg, 22% yield, mp 53−54 °C; H NMR (500
1
MHz, CDCl3) δ 8.03−7.98 (m, 4H), 7.57 (t, J = 7.4 Hz, 1H), 7.54−
7.51 (m, 2H), 7.43 (t, J = 7.8 Hz, 2H), 7.38 (t, J = 7.5 Hz, 1H), 7.35
(s, 1H), 7.29 (d, J = 8.2 Hz, 2H), 7.24 (t, J = 7.9 Hz, 2H), 6.48 (d, J =
3.4 Hz, 1H), 6.43 (dd, J = 3.3, 1.8 Hz, 1H), 5.94 (t, J = 6.7 Hz, 1H),
4.53 (qd, J = 12.7, 6.7 Hz, 2H), 2.39 (s, 3H); 13C NMR (126 MHz,
CDCl3) δ 206.6, 169.9, 166.0, 147.1, 145.1, 143.2, 135.3, 133.9, 133.3,
131.9, 129.7, 129.6, 129.2, 128.4, 128.1, 127.8, 112.0, 110.0, 106.0,
97.1, 60.5, 21.6; HRMS (ESI-TOF) m/z calcd for C29H23NO6NaS [M
+ Na]+536.1144, found 536.1148.
139−140 °C; H NMR (400 MHz, CDCl3) δ 8.07−8.00 (m, 2H),
7.59 (dd, J = 1.7, 0.8 Hz, 1H), 7.57−7.54 (m, 2H), 7.41−7.36 (m,
3H), 7.34−7.30 (m, 3H), 7.21 (dd, J = 3.5, 0.8 Hz, 1H), 7.02 (dd, J =
3.6, 0.7 Hz, 1H), 6.51 (dd, J = 3.5, 1.7 Hz, 1H), 6.32 (dd, J = 3.6, 1.7
Hz, 1H), 5.99 (t, J = 6.4 Hz, 1H), 4.88−4.56 (m, 2H), 2.41 (s, 3H);
13C NMR (126 MHz, CDCl3) δ 207.0, 158.2, 146.9, 146.6, 145.39,
145.37, 144.1, 135.6, 133.8, 129.9, 129.4, 129.0, 128.7, 126.0, 119.7,
119.0, 113.3, 112.2, 112.1, 96.2, 60.6, 21.8; HRMS (ESI-TOF) m/z
calcd for C27H21NO7NaS [M + Na]+ 526.0936, found 526.0931.
4-Phenyl-4-(N-tosylcyclopentanecarboxamido)buta-2,3-dien-1-
ylcyclopentanecarboxylate (7g). By following GP 2 (2.0 mmol), the
4-(Naphthalen-2-yl)-4-(N-tosylbenzamido)buta-2,3-dien-1-yl
benzoate (7m). By following GP 1 (0.2 mmol), the compound was
1
1
obtained as a yellow solid: 49.0 mg, 38% yield, mp 59−60 °C; H
compound was obtained as colorless oil: 144.0 mg, 18% yield; H
NMR (500 MHz, CDCl3) δ 8.08 (d, J = 8.0 Hz, 2H), 8.00 (d, J = 6.6
Hz, 3H), 7.83−7.78 (m, 3H), 7.56 (t, J = 7.4 Hz, 1H), 7.53−7.48 (m,
5H), 7.42 (t, J = 7.8 Hz, 2H), 7.30 (dd, J = 7.7, 3.6 Hz, 3H), 7.13 (t, J
= 7.9 Hz, 2H), 5.90 (t, J = 6.7 Hz, 1H), 4.48−4.52 (m, 2H), 2.40 (s,
3H); 13C NMR (126 MHz, CDCl3) δ 208.4, 170.3, 166.2, 145.4,
135.4, 134.1, 133.45, 133.4, 133.3, 131.9, 131.2, 129.9, 129.8, 129.7,
129.4, 128.7, 128.65, 128.6, 128.2, 127.8, 126.8, 126.7, 125.4, 123.6,
114.2, 96.4, 60.6, 21.8; HRMS (ESI-TOF) m/z calcd for
C35H27NO5NaS [M + Na]+ 596.1508, found 596.1502.
General Procedure for the Synthesis of 5-Vinyloxazoles. In a
10 mL flame-dried Schlenk tube, AgBF4 (10 mol %) and N-sulfonyl
allenylamide 7 (0.15 mmol) were introduced under argon and
dissolved in 2 mL of dry and degassed toluene. The resulting yellow
solution was stirred at 80 °C for 16−20 h and concentrated under
reduced pressure. Purification by flash chromatography on silica gel
(petroleum ether/ether: 100/1) afforded the expected product.
2,4-Diphenyl-5-vinyloxazole (8a). By following the general
procedure (0.20 mmol), the compound was obtained as a yellow
solid: 39.4 mg, 81% yield, mp 59−60 °C; 1H NMR (500 MHz,
CDCl3) δ 8.17−8.11 (m, 2H), 7.77−7.71 (m, 2H), 7.50−7.43 (m,
5H), 7.39−7.34 (m, 1H), 6.87 (dd, J = 17.3, 11.3 Hz, 1H), 5.93 (dd, J
= 17.3, 1.2 Hz, 1H), 5.40 (dd, J = 11.3, 1.2 Hz, 1H); 13C NMR (126
MHz, CDCl3) δ 160.3, 145.1, 138.3, 132.1, 130.7, 128.9, 128.8, 128.3,
127.9, 127.5, 126.8, 122.5, 115.5; HRMS (ESI-TOF) m/z calcd for
C17H13NONa [M + Na]+ 270. 0895, found 270.0894.
2-(3-Bromophenyl)-4-phenyl-5-vinyloxazole (8b). By following
the general procedure (0.15 mmol), the compound was obtained as
colorless oil: 38.6 mg, 79% yield; 1H NMR (500 MHz, CDCl3) δ 8.28
(t, J = 1.7 Hz, 1H), 8.10−8.02 (m, 1H), 7.74−7.71 (m, 2H), 7.58
(ddd, J = 8.0, 1.9, 1.0 Hz, 1H), 7.49−7.42 (m, 2H), 7.41−7.30 (m,
2H), 6.86 (dd, J = 17.3, 11.3 Hz, 1H), 5.95 (dd, J = 17.3, 1.1 Hz, 1H),
5.43 (dd, J = 11.3, 1.1 Hz, 1H); 13C NMR (126 MHz, CDCl3) δ 158.7,
145.5, 138.4, 133.5, 131.8, 130.5, 129.6, 129.3, 128.9, 128.4, 127.8,
125.2, 123.0, 122.3, 116.1; HRMS (ESI-TOF) m/z calcd for
C17H12NONaBr [M + Na]+ 348. 0000, found 347.9994.
NMR (500 MHz, CDCl3) δ 7.94 (d, J = 8.2 Hz, 2H), 7.43 (d, J = 7.5
Hz, 2H), 7.41−7.37 (m, 2H), 7.31 (t, J = 7.5 Hz, 3H), 6.13 (s, 1H),
4.85−4.78 (m, 2H), 2.85−2.78 (m, 2H), 2.44 (s, 3H), 1.94−1.49 (m,
16H); 13C NMR (126 MHz, CDCl3) δ 206.2, 176.8, 176.4, 144.8,
136.3, 133.4, 129.2, 128.9, 128.6, 125.5, 111.8, 96.8, 60.2, 43.6, 30.1,
30.0, 26.3, 25.8, 21.7; HRMS (ESI-TOF) m/z calcd for
C29H33NO5NaS [M + Na]+ 530.1977, found 530.1979.
4-Phenyl-4-(N-tosylacetamido)buta-2,3-dien-71-yl acetate (7h).
By following GP 2 (2.0 mmol), the compound was obtained as a
1
yellow solid: 543.7 mg, 68% yield, mp 130−131 °C; H NMR (500
MHz, CDCl3) δ 7.95 (d, J = 8.2 Hz, 2H), 7.46−7.42 (m, 2H), 7.41−
7.37 (m, 2H), 7.35−7.30 (m, 3H), 6.11 (s, 1H), 4.86−4.75 (m, 2H),
2.44 (s, 3H), 2.09 (s, 6H); 13C NMR (126 MHz, CDCl3) δ 205.4,
169.9, 145.1, 136.0, 132.9, 129.3, 129.2, 129.0, 128.7, 125.4, 112.8,
96.8, 60.0, 23.9, 21.7, 20.7; HRMS (ESI-TOF) m/z calcd for
C21H21NO5NaS [M + Na]+ 422.1038, found 422.1046.
4-(2-Fluorophenyl)-4-(N-tosylbenzamido)buta-2,3-dien-1-yl ben-
zoate (7i). By following GP 1 (0.4 mmol), the compound was
1
obtained as a yellow solid: 104.3 mg, 49% yield, mp 124−125 °C; H
NMR (500 MHz, CDCl3) δ 8.05−8.01 (m, 2H), 7.99 (dt, J = 8.4, 1.5
Hz, 2H), 7.69 (td, J = 7.9, 1.7 Hz, 1H), 7.59−7.54 (m, 1H), 7.49−7.46
(m, 2H), 7.45−7.40 (m, 2H), 7.39−7.33 (m, 1H), 7.30−7.26 (m, 3H),
7.25−7.19 (m, 3H), 7.00 (ddd, J = 11.3, 8.1, 1.2 Hz, 1H), 5.70 (t, J =
6.9 Hz, 1H), 4.48 (qd, J = 12.5, 6.9 Hz, 2H), 2.37 (s, 3H); 13C NMR
(126 MHz, CDCl3) δ 210.0 (d, J = 2.7 Hz), 170.0, 166.1, 159.6 (d, J =
252.8 Hz), 145.4, 135.2, 134.2, 133.4, 131.9, 130.2 (d, J = 8.6 Hz),
129.8, 129.7, 129.3, 128.6, 128.5, 128.2, 127.8, 124.6 (d, J = 3.6 Hz),
122.2 (d, J = 8.7 Hz), 116.4 (d, J = 21.7 Hz), 107.5, 94.0, 60.6, 21.7;
19F NMR (377 MHz, CDCl3) δ −112.0; HRMS (ESI-TOF) m/z calcd
for C31H24NO5FNaS [M + Na]+ 564.1257, found 564.1248.
4-(3-Fluorophenyl)-4-(N-tosylbenzamido)buta-2,3-dien-1-yl ben-
zoate (7j). By following GP 1 (0.4 mmol), the compound was
1
obtained as a white solid: 161.7 mg, 79% yield, mp 113−114 °C; H
NMR (500 MHz, CDCl3) δ 8.03 (d, J = 8.3 Hz, 2H), 7.99 (dd, J = 8.2,
1.0 Hz, 2H), 7.69 (td, J = 7.9, 1.5 Hz, 1H), 7.59−7.54 (m, 1H), 7.49−
7.45 (m, 2H), 7.43 (t, J = 7.8 Hz, 2H), 7.39−7.34 (m, 1H), 7.31−7.26
(m, 3H), 7.25−7.18 (m, 3H), 7.04−6.97 (m, 1H), 5.70 (t, J = 6.9 Hz,
1H), 4.48 (qd, J = 12.5, 6.9 Hz, 2H), 2.36 (s, 3H); 13C NMR (126
MHz, CDCl3) δ 210.1, 170.0, 166.1, 159.6 (d, J = 252.7 Hz), 145.4,
135.2, 134.2, 133.4, 131.9, 130.2 (d, J = 8.5 Hz), 129.8, 129.7, 129.3,
128.7, 128.6, 128.4, 128.2, 127.8, 124.6 (d, J = 3.7 Hz), 122.2 (d, J =
2-(3-Methoxyphenyl)-4-phenyl-5-vinyloxazole (8c). By following
the general procedure (0.20 mmol), the compound was obtained as
1
colorless oil: 44.6 mg, 81% yield; H NMR (500 MHz, CDCl3) δ
7.76−7.71 (m, 3H), 7.67 (dd, J = 2.5, 1.5 Hz, 1H), 7.47−7.43 (m,
2H), 7.40−7.34 (m, 2H), 7.01 (ddd, J = 8.3, 2.6, 0.9 Hz, 1H), 6.86
(dd, J = 17.3, 11.3 Hz, 1H), 5.93 (dd, J = 17.3, 1.2 Hz, 1H), 5.40 (dd, J
K
dx.doi.org/10.1021/jo401330t | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
= 11.3, 1.2 Hz, 1H), 3.89 (s, 3H); 13C NMR (126 MHz, CDCl3) δ
160.2, 160.0, 145.1, 138.3, 132.0, 130.0, 128.8, 128.7, 128.3, 127.9,
122.4, 119.3, 117.1, 115.6, 111.5, 55.6; HRMS (ESI-TOF) m/z calcd
for C18H15NO2Na [M + Na]+ 300. 1000, found 300.1006.
CDCl3) δ 8.17−8.08 (m, 2H), 7.71 (td, J = 7.6, 1.8 Hz, 1H), 7.51−
7.43 (m, 3H), 7.36 (dddd, J = 8.2, 7.2, 5.1, 1.8 Hz, 1H), 7.24 (td, J =
7.5, 1.1 Hz, 1H), 7.16 (ddd, J = 10.1, 8.3, 1.0 Hz, 1H), 6.70 (ddd, J =
17.4, 11.3, 2.7 Hz, 1H), 5.89 (dt, J = 17.5, 1.0 Hz, 1H), 5.37 (dd, J =
11.3, 1.2 Hz, 1H); 13C NMR (126 MHz, CDCl3) δ 159.7 (d, J = 248.3
Hz), 146.5, 132.9, 131.4 (d, J = 3.0 Hz), 130.7, 130.3 (d, J = 8.2 Hz),
128.9, 127.4, 126.8, 124.6 (d, J = 3.5 Hz), 122.5 (d, J = 7.7 Hz), 119.9
(d, J = 14.5 Hz), 116.2 (d, J = 22.1 Hz), 115.4; 19F NMR (377 MHz,
CDCl3) δ −114.0; HRMS (ESI-TOF) m/z calcd for C17H12NOFNa
[M + Na]+ 288. 0801, found 288.0809.
4-(4-Bromophenyl)-2-phenyl-5-vinyloxazole (8k). By following
the general procedure (0.15 mmol), the compound was obtained as
colorless oil: 48.0 mg, 80% yield; 1H NMR (500 MHz, CDCl3) δ 8.12
(ddd, J = 7.1, 4.1, 2.3 Hz, 2H), 7.70−7.54 (m, 4H), 7.52−7.41 (m,
3H), 6.81 (dd, J = 17.3, 11.3 Hz, 1H), 5.95 (dd, J = 17.3, 1.1 Hz, 1H),
5.43 (dd, J = 11.3, 1.1 Hz, 1H); 13C NMR (126 MHz, CDCl3) δ 160.4,
145.2, 137.2, 132.0, 131.0, 130.8, 129.3, 128.9, 127.3, 126.8, 122.4,
122.1, 116.2; HRMS (ESI-TOF) m/z calcd for C17H12NONaBr [M +
Na]+ 348. 0000, found 348.0008.
4-Phenyl-2-(p-tolyl)-5-vinyloxazole (8d). By following the general
procedure (0.15 mmol), the compound was obtained as colorless oil:
1
31.7 mg, 81% yield; H NMR (500 MHz, CDCl3) δ 8.08−7.99 (m,
2H), 7.77−7.71 (m, 2H), 7.47−7.42 (m, 2H), 7.38−7.33 (m, 1H),
7.27 (d, J = 7.9 Hz, 2H), 6.86 (dd, J = 17.3, 11.3 Hz, 1H), 5.91 (dd, J =
17.3, 1.2 Hz, 1H), 5.38 (dd, J = 11.3, 1.2 Hz, 1H), 2.41 (s, 3H); 13C
NMR (126 MHz, CDCl3) δ 160.5, 144.8, 141.0, 138.2, 132.2, 129.6,
128.8, 128.2, 127.8, 126.7, 124.8, 122.5, 115.2, 21.7; HRMS (ESI-
TOF) m/z calcd for C18H15NONa [M + Na]+ 284. 1051, found
284.1043.
2-(4-Fluorophenyl)-4-phenyl-5-vinyloxazole (8e). By following the
general procedure (0.15 mmol), the compound was obtained as
1
colorless oil: 31.0 mg, 78% yield; H NMR (500 MHz, CDCl3) δ
8.18−8.08 (m, 2H), 7.77−7.69 (m, 2H), 7.51−7.42 (m, 2H), 7.40−
7.33 (m, 1H), 7.20−7.13 (m, 2H), 6.86 (dd, J = 17.3, 11.3 Hz, 1H),
5.91 (dd, J = 17.3, 1.2 Hz, 1H), 5.40 (dd, J = 11.3, 1.2 Hz, 1H); 13C
NMR (126 MHz, CDCl3) δ 164.4 (d, J = 251.4 Hz), 159.5, 145.1,
138.3, 132.0, 128.92, 128.86, 128.3, 127.8, 123.8 (d, J = 3.2 Hz), 122.4,
116.1 (d, J = 22.2 Hz), 115.5; 19F NMR (377 MHz, CDCl3) δ −109.7;
HRMS (ESI-TOF) m/z calcd for C17H12NOFNa [M + Na]+ 288.
0801, found 288.0802.
4-(Furan-2-yl)-2-phenyl-5-vinyloxazole (8l). By following the
general procedure (0.20 mmol), the compound was obtained as
1
colorless oil: 18.8 mg, 40% yield; H NMR (500 MHz, CDCl3) δ
8.16−8.07 (m, 2H), 7.51 (dd, J = 1.8, 0.8 Hz, 1H), 7.50−7.42 (m,
3H), 7.13 (dd, J = 17.5, 11.4 Hz, 1H), 6.83 (dd, J = 3.4, 0.7 Hz, 1H),
6.52 (dd, J = 3.4, 1.8 Hz, 1H), 5.90 (dd, J = 17.5, 1.2 Hz, 1H), 5.41
(dd, J = 11.4, 1.2 Hz, 1H); 13C NMR (126 MHz, CDCl3) δ 160.7,
147.9, 144.5, 142.9, 130.8, 130.1, 128.9, 127.2, 126.9, 122.6, 115.1,
111.6, 108.7; HRMS (ESI-TOF) m/z calcd for C15H11NO2Na [M +
Na]+ 260. 0687, found 260.0688.
2-(Furan-2-yl)-4-phenyl-5-vinyloxazole (8f). By following the
general procedure (0.12 mmol), the compound was obtained as
1
colorless oil: 16.2 mg, 58% yield; H NMR (500 MHz, CDCl3) δ
7.78−7.69 (m, 2H), 7.59 (dd, J = 1.8, 0.8 Hz, 1H), 7.49−7.41 (m,
2H), 7.40−7.30 (m, 1H), 7.11 (dd, J = 3.5, 0.8 Hz, 1H), 6.86 (dd, J =
17.3, 11.3 Hz, 1H), 6.57 (dd, J = 3.5, 1.8 Hz, 1H), 5.91 (dd, J = 17.3,
1.2 Hz, 1H), 5.41 (dd, J = 11.3, 1.2 Hz, 1H); 13C NMR (126 MHz,
CDCl3) δ 153.1, 144.8, 144.6, 143.0, 138.0, 131.6, 128.8, 128.4, 127.9,
122.2, 115.9, 112.2, 112.1; HRMS (ESI-TOF) m/z calcd for
C15H11NO2Na [M + Na]+ 260. 0687, found 260.0678.
4-(Naphthalen-2-yl)-2-phenyl-5-vinyloxazole (8m). By following
the general procedure (0.20 mmol), the compound was obtained as a
1
white solid: 38.2 mg, 65% yield, mp 68−69 °C; H NMR (500 MHz,
CDCl3) δ 8.40−8.06 (m, 3H), 7.99−7.81 (m, 4H), 7.63−7.38 (m,
5H), 6.98 (dd, J = 17.3, 11.3 Hz, 1H), 5.98 (dd, J = 17.3, 1.2 Hz, 1H),
5.45 (dd, J = 11.3, 1.2 Hz, 1H); 13C NMR (126 MHz, CDCl3) δ 160.4,
145.4, 138.3, 133.6, 133.2, 130.7, 129.5, 128.9, 128.5, 128.4, 127.9,
127.5, 127.0, 126.8, 126.6, 126.5, 125.6, 122.6, 115.7; HRMS (ESI-
TOF) m/z calcd for C21H15NONa [M + Na]+ 320. 1051, found
320.1054.
2-Cyclopentyl-4-phenyl-5-vinyloxazole (8g). By following the
general procedure (0.23 mmol), the compound was obtained as
1
colorless oil: 36.2 mg, 65% yield; H NMR (500 MHz, CDCl3) δ
7.69−7.58 (m, 2H), 7.46−7.37 (m, 2H), 7.35−7.28 (m, 1H), 6.79 (dd,
J = 17.3, 11.3 Hz, 1H), 5.75 (dd, J = 17.3, 1.3 Hz, 1H), 5.29 (dd, J =
11.3, 1.3 Hz, 1H), 3.26 (p, J = 8.1 Hz, 1H), 2.19−2.04 (m, 2H), 2.05−
1.91 (m, 2H), 1.90−1.77 (m, 2H), 1.75−1.63 (m, 2H); 13C NMR
(126 MHz, CDCl3) δ 167.2, 144.5, 136.6, 132.3, 128.7, 127.9, 127.7,
122.6, 114.5, 38.8, 31.7, 25.8; HRMS (ESI-TOF) m/z calcd for
C16H17NONa [M + Na]+ 262. 1208, found 262.1201.
ASSOCIATED CONTENT
■
S
* Supporting Information
1H and 13C NMR spectra of all compounds and crystallographic
data (CIF) of 2a. This material is available free of charge via the
Internet at http://pubs.acs.org.
2-Methyl-4-phenyl-5-vinyloxazole (8h). By following the general
procedure (0.50 mmol), the compound was obtained as colorless oil:
62.7 mg, 66% yield; H NMR (500 MHz, CDCl3) δ 7.70−7.58 (m,
1
AUTHOR INFORMATION
Corresponding Author
*E-mail: bswan@dicp.ac.cn.
Notes
■
2H), 7.46−7.37 (m, 2H), 7.36−7.29 (m, 1H), 6.79 (dd, J = 17.3, 11.3
Hz, 1H), 5.76 (dd, J = 17.3, 1.3 Hz, 1H), 5.31 (dd, J = 11.3, 1.3 Hz,
1H), 2.51 (s, 3H); 13C NMR (126 MHz, CDCl3) δ 160.5, 144.9,
136.8, 132.1, 128.8, 128.0, 127.6, 122.4, 114.8, 14.1; HRMS (ESI-
TOF) m/z calcd for C12H11NONa [M + Na]+ 208. 0738, found
208.0736.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
4-(2-Fluorophenyl)-2-phenyl-5-vinyloxazole (8i). By following the
■
general procedure (0.15 mmol), the compound was obtained as a
We thank the financial support from the National Basic
Research Program of China (2010CB833300) and the National
Natural Science Foundation of China (21172218).
1
white solid: 30.2 mg, 76% yield, mp 76−77 °C; H NMR (500 MHz,
CDCl3) δ 8.18−8.07 (m, 2H), 7.71 (td, J = 7.5, 1.8 Hz, 1H), 7.52−
7.43 (m, 3H), 7.36 (dddd, J = 8.2, 7.1, 5.1, 1.8 Hz, 1H), 7.28−7.20 (m,
1H), 7.16 (ddd, J = 10.2, 8.3, 1.0 Hz, 1H), 6.69 (ddd, J = 17.4, 11.3,
2.7 Hz, 1H), 5.89 (dt, J = 17.4, 1.0 Hz, 1H), 5.37 (dd, J = 11.3, 1.2 Hz,
1H); 13C NMR (126 MHz, CDCl3) δ 159.7 (d, J = 248.0 Hz), 146.5,
132.9, 131.4 (d, J = 3.0 Hz), 130.7, 130.3 (d, J = 8.2 Hz), 128.9, 127.4,
126.8, 124.6 (d, J = 3.5 Hz), 122.5 (d, J = 7.7 Hz), 119.9 (d, J = 14.4
Hz), 116.2 (d, J = 22.1 Hz), 115.4; 19F NMR (377 MHz, CDCl3) δ
−114.1; HRMS (ESI-TOF) m/z calcd for C17H12NOFNa [M + Na]+
288. 0801, found 288.0806.
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