Pd/Cu-Catalyzed tandem head-to-tail dimerization/cycloisomerization of terminal ynamides for the synthesis of 5-vinyloxazolones

Article abstract of DOI:10.1039/C7OB00381A

An attractive and novel methodology involving Pd/Cu-catalyzed tandem head-to-tail dimerization/cycloisomerization of terminal ynamides for the synthesis of 3,5-disubstituted oxazolones was developed. Under Pd(PPh₃)₂Cl₂/CuI

Full text of DOI:10.1039/C7OB00381A

View Article Online
View Journal
Organic &
Biomol ec ular
Chemistry
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: L. Tang, H. Huang,
Y. Xi, G. He and H. Zhu, Org. Biomol. Chem., 2017, DOI: 10.1039/C7OB00381A.
Volume 14 Number
1
7
January 2016 Pages 1–372
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Organic &
Biomolecular
Chemistry
www.rsc.org/obc
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
author guidelines.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the ethical guidelines, outlined
in our author and reviewer resource centre, still apply. In no
event shall the Royal Society of Chemistry be held responsible
for any errors or omissions in this Accepted Manuscript or any
consequences arising from the use of any information it contains.
ISSN 1477-0520
COMMUNICATION
Takeharu Haino et al.
Solvent-induced emission of organogels based on tris(phenylisoxazolyl)
benzene
rsc.li/obc

Page 1 of 7
Org aP nl ei ca s &e dB oi o nmo to al ed cj uu sl at rm Ca hr ge imn si stry
View Article Online
DOI: 10.1039/C7OB00381A
Journal Name
ARTICLE
Pd/Cu-Catalyzed
Tandem
Head-to-Tail
Dimerization/
Cycloisomerization of Terminal Ynamides for the Synthesis of 5-
Vinyloxazolones
Received 00th January 20xx,
Accepted 00th January 20xx
†
,a
†,a
a
a
a,*
DOI: 10.1039/x0xx00000x
Luning Tang, Hai Huang, Yang Xi, Guangke He and Hongjun Zhu
www.rsc.org/
An attractive and novel methodology involving Pd/Cu-catalyzed tandem head-to-tail dimerization/cycloisomerization of
terminal ynamides for the synthesis of 3,5-disubstituted oxazolones was developed. Under Pd(PPh Cl /CuI cooperative
catalyzed reaction conditions, it provided an efficient access to 5-vinyloxazolones with exceptional functional group
tolerance and good chemoselectivity. The control experiments demonstrated that Pd(PPh Cl serves a key role in
)
3 2
2
)
3 2
2
dimerization of terminal ynamides and shows low catalytic activity in the intramolecular cyclization. Moreover, hetero-
Diels–Alder reaction of product 5-vinyloxazolones was also described, which provide the polycyclic oxazolones in good
yield.
Introduction
Concurrent tandem catalysis (CTC), which involves the cooperative
action of two or more catalytic cycles in a single reactor without
1
2
isolation and purification between steps, has emerged as
conceptually appealing transformations in organic synthesis.
Obviously, there are two major benefits in CTC: 1) saving time by
operating simultaneously, 2) reducing yield losses without
purification of intermediates. However, each catalyst must be
compatible with substrates, intermediates and other catalysts, as
3
while as exhibit reaction sequence selectivity. Therefore, designing
and developing efficient CTC is of great necessity and yet remains a
great challenge.
Oxazolone and its derivatives have received significant attention
in recent years owing to their both biological properties and
pharmaceutical applications (Scheme 1). They are widely used in
Scheme 1. Biologically Active and Pharmaceutically Important
Oxazolone Derivatives.
4
5
medicine and pesticide as fenoxaprop (A), phosalone (B) and
6
During the past decade, tremendous efforts have been devoted
to the development of versatile methods for constructing the
linezolid (C). In addition, Noriaki Kudo reported that 4-halo-
oxazolones (D) also show a wide range of herbicidal activity from
8
7
multisubstituted oxazolones, among which, the cycloisomerization
broadleaf to narrowleaf weeds. Therefore, the development of
of N-alkynyl tert-butyloxycarbamates was considered as a rapid and
methods for the synthesis of different substituted oxazolones is
important and currently attracting growing interest.
straightforward method to synthesize oxazolones. For instance,
9
Gagosz’s group first reported Au-catalyzed cycloisomerization of
ynamides in 2008, which provided an efficient and rapid process for
the synthesis of 3,5-disubstituted oxazolones. Subsequently, many
different types of metal catalysts such as palladium and copper had
also been developed for the cycloisomerization of N-alkynyl tert-
10
butyloxycarbamates (Scheme 2, a). Recently, our group reported a
novel method for the construction of 4-halo-oxazolones by the
a.
Department of Applied Chemistry, College of Chemistry and Molecular
Engineering, Nanjing Tech University, Nanjing 211816, People’s Republic of China
E-mail: zhuhj@njtech.edu.cn
These authors contributed equally to this work.
11
halopalladation type reaction. Inspired by these excellent works
12
and our interest in the exploration of the reactivity of ynamides,
†
we put further attention in the cycloisomerization of terminal
ynamides. Although Yamamoto and Hsung’s group reported their
independent findings that head-to-tail dimerization of terminal
Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI: 10.1039/x0xx00000x
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 1
Please do not adjust margins

Org aP nl ei ca s &e dB oi o nmo to al ed cj uu sl at rm Ca hr ge imn si stry
Page 2 of 7
ARTICLE
ynamides would generate en-ynamides based on totally different Table 1. Optimization of Reaction Conditions.
Journal Name
a
View Article Online
DOI: 10.1039/C7OB00381A
13
reaction conditions (Scheme 2, b), we were still interested in
exploring the activity of terminal ynamides containing nucleophilic
11, 14
group (e.g. Boc).
What’s more, no any proposed mechanism of
the dimerization of terminal ynamides has been given. To the best
of our knowledge, this is the first Pd/Cu-catalyzed tandem head-to-
tail dimerization / cycloisomerization of terminal ynamides for
synthesis of 5-vinyl-oxazolones based on CTC (Scheme 2, c).
2
a/3a yield
entry
Pd
base
ligand
(
%)
1
2
3
4
5
6
7
8
9
PdCl2
Pd(OAc)2
Pd (dba)
Et N
P(2-MeC H )
--/15
NR
3
6
4 3
Et N
P(2-MeC H )
3
6
4 3
Et N
P(2-MeC H )
--/23
--/56
63/--
41/25
46/24
--/40
--/59
--/38
--/53
--/62
43/--
26/26
--/14
25/19
--/50
--/41
36/11
--/--
2
3
3
6
4 3
Pd(PPh ) Cl
Et N
P(2-MeC H )
3
2
2
3
6
4 3
Pd(PPh3)4
Et N
P(2-MeC H )
3
6
4 3
Pd(PPh ) Cl
Et N
DPEPhos
RuPhos
PPh3
3
2
2
3
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
--
)
)
)
)
)
)
)
)
)
)
)
)
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Et N
3
2
2
3
3
3
3
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Et N
3
Et N
P(Cy)3
3
1
1
1
1
1
1
1
0
1
2
3
4
5
6
Et N
LB•Phos•HBF4
P(t-Bu)3
P(Cy)3
3
Et N
3
DIPEA
DBU
Py
P(Cy)3
P(Cy)3
P(Cy)3
--
P(Cy)3
P(Cy)3
P(Cy)3
P(Cy)3
Scheme 2. Metal-catalyzed Cyclization of the N-Alkynyl
alkyloxycarbamates.
--
DIPEA
DIPEA
DIPEA
DIPEA
DIPEA
b
17
Results and discussion
c
18
Initially, we investigated the cycloisomerization of tert-butyl
ethynyl (phenyl)carbamate 1a which was treated with 10 mol% of
CuI, 5.0 mol% of PdCl , and 2.0 equiv of Et N in THF using P(2-
19
d
20
Pd(PPh
3
)
2
Cl
2
a
2
3
The reaction was carried out with 1a (0.3 mmol), Pd catalysts (5.0
MeC H ) as ligand. It was found that an unexpected tert-butyl (1- mol%), bases (2.0 equiv), ligands (10 mol%) and CuI (10 mol%) in
6
4 3
b
d
(
2-oxo-3-phenyl-2,3-dihydrooxazol-5-yl)vinyl)(phenyl)-carbamate 3a THF (2.0 mL) under N atmosphere for 18 h; NR = No Reaction;
was obtained in 15% yield after 18 h (Table 1, entry 1). Then, toluene was used as solvent; 1,4-dioxane was used as solvent;
2
c
different palladium catalysts, as Pd(OAc) , Pd (dba) , Pd(PPh ) Cl , reaction was carried without CuI loading.
2
2
3
3 2
2
Pd(PPh ) , were applied in this transformation. Among them,
3
4
Pd(PPh ) Cl gave the best performance that product 3a was
3
2
2
obtained in 56% yield (Table 1, entries 2-4). It is worth mentioning
that only head-to-tail dimerization product 2a was obtained by
using Pd(PPh ) as catalyst (Table 1, entry 5). The structure of 2a Scheme 3. Synthesis of Terminal Ynamides. a) NBS (1.25 equiv),
3
4
was further confirmed by using single-crystal X-ray structure AgNO
analysis (see Figure 1, 2a). To further optimize the reaction, Phen (10 mol%), K
different ligands were examined and results demonstrated that equiv), THF, 0 C-rt.
(5.0 mol%), acetone, rt; b) CuSO
·5H
PO (2.0 equiv), toluene, 85 C; c) TBAF (1.1
4
O (5.0 mol%), 1,10-
3
4
2
15
o
3
o
ligands also had great effect on this reaction. For example, en-
We first synthesized several terminal yanmides 1a-1p to further
ynamide 2a was obtained by utilizing DPEPhos and RuPhos as
ligands (Table 1, entries 6-7). In contrast, only 5-vinyloxazolone 3a
examine the flexibility of this transition according to the previously
12a, 17
reported methodology (Scheme 3).
Next, we tested the
16
could be obtained when PPh , P(Cy) , LB·Phos·HBF and P(t-Bu)3
3
3
reactivity of those terminal ynamides 1a-1p above in this
transformation under the optimized reaction conditions (Table 2).
First of all, methyl on the ortho-position of N-aryl ring was tolerated
and produced the corresponding oxazolones 3b in 52% yield after
were applied as ligand (Table 1, entries 8-11). Next, different bases
were also examined in which DIPEA showed the best performance
to give corresponding product 3a in 62% yield (Table 1, entries 12-
1
4). The less amount of corresponding product 3a was provided in
4
2 h (Table 2, 3b). Next, ynamides with electron-donating groups,
the absence of bases or ligands (Table 1, entries 15-16). Among the
solvents screened, THF was superior to toluene and 1,4-dioxane
such as Me and MeO on the meta-position of N-aryl ring, gave the
corresponding products in 48-65% yields (Table 2, 3c-3d). In
addition, ynamides with electron-withdrawing groups on the meta-
(
Table 1, entries 17-18). A blank experiment indicated that 1a could
produce 2a in 36% yield and 3a only in 11% yield without CuI
loading (Table 1, entry 19). What’s more, it could not generate the
product 2a or desired product 3a in absence of Pd-catalyst (Table 1,
entry 20).
position of the N-aryl ring, such as F, Cl, Br, and CF , were also
tolerated and generated the corresponding 5-vinyloxazolones in 48-
3
5
9% yields (Table 2, 3e-3h). In general, ynamides bearing electron-
withdrawing groups gave lower yields than those bearing electron-
donating groups on the meta-position. The structure of 3e was
2
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 3 of 7
Org aP nl ei ca s &e dB oi o nmo to al ed cj uu sl at rm Ca hr ge imn si stry
Journal Name
further confirmed by using single-crystal X-ray structure analysis
ARTICLE
View Article Online
DOI: 10.1039/C7OB00381A
15
(
see Figure 1, 3e). Meanwhile, groups on the para-position of the
N-aryl ring were also tested, the yields of the desired products were
in 46%-70% yields. And the para-effect demonstrated that electron-
withdrawing groups gave higher yields (Table 2, 3i-3l). Furthermore,
ynamides with N-benzyl also successfully produced the desired 5-
vinyloxazolones in acceptable yields (Table 2, 3m-3n). Finally,
substrates possessing benzo[d][1,3]dioxol-5-yl and 2-naphthyl
groups on N atom supplied the products in 48-66% yields (Table 2,
Scheme 5. Diels-Alder Reaction of 5-Vinyloxazolones.
As we confirmed, this tandem reaction would lose efficiency
whatever in absence of Pd(II) or CuI (Table 1, entries 19-20). To
further understand the mechanism of this reaction, control
experiments were conducted for the cycloisomerization of en-
ynamide 2a (Table 3). Although Zhu’s group reported that
cycloisomerization of N-alkynyl tert-butyloxycarbamates could
provide oxazolones efficiently only rely on simplex copper salts or
3o-3p).
a
Table 2. Pd/Cu-Catalyzed Formation of 5-Vinyloxazolones.
10b-10c
palladium salts,
we still wanted to figure out what is essential
in the second step of this tandem reaction. The final product 3a was
generated in 74% yield by utilizing CuI as catalyst in presence of
ligand and base (Table 3, entry 1). However, next control
experiment using Pd(PPh ) Cl as catalyst for the cycloisomerization
3
2
2
of en-ynamide 2a were carried out, which only afforded 3a in 38%
yield (Table 3, entry 2). These results suggested that the second
step cycloisomerization was primarily promoted by CuI. What’s
more, it is demonstrated that both of ligand and base also have an
important effect on the second cycloisomerization (Table 3, entries
3
-4).
a
Table 3. Control Experiments for the Cyclization of 2a.
a
Reaction conditions: 1a-1p (0.3 mmol), Pd(PPh ) Cl (5.0 mol %),
3
2
2
CuI (10 mol%), P(Cy) (10 mol%), DIPEA (2.0 equiv) in THF (2.0 mL)
3
at 65 °C.
entry
deviation from standard conditions
none
yield (%)
1
2
3
74
38
21
24
PdCl (PPh ) (5 mol%) instead of CuI (10 mol%)
2
3 2
without P(Cy)3
4
without P(Cy) , DIPEA
3
a
Reaction conditions: 2a (0.3 mmol), CuI (10 mol%), P(Cy) (10
3
2a
3e
mol%), DIPEA (2.0 equiv) in THF (2.0 mL) at 65 °C for 18h.
Figure 1. Single-crystal X-ray Structure of 2a and 3e.
Based on the experimental results and the reported literature, a
To demonstrate the synthetic potential of this strategy, 1a (1.05 g, proposed mechanism for this Pd/Cu-catalyzed tandem head-to-tail
5
.0 mmol) was allowed to react under the optimized conditions. dimerization/cycloisomerization of terminal ynamides is shown in
This reaction could be scaled up to 5.0 mmol with comparable Scheme 6. The activation of the triple bond in terminal ynamides 1
18
efficiency in a moderate yield, illustrating its potential industrial with Pd(II) produces the intermediate A. At the same time, copper
applications in the future (Scheme 4).
acetylide B is generated from a second molecule of terminal
ynamide 1 with CuX in the presence of DIPEA. Then, Intermediate A
undergos a transmetallation with copper acetylide B leading to the
alkynyl palladium complex C, which provides σ-vinylpalladium
19
intermediate D via a followed carbometalation. The following
protonation of intermediate D gives the dimerization product 2 and
19b
regenerates Pd(II) species.
oxazolones are produced mainly by CuI-catalyzed
cycloisomerization of en-ynamides 2.
Finally, the corresponding 5-vinyl-
Scheme 4. Scale-up Experiment.
3
10a-10c
The Diels-Alder reaction of 5-vinyl-oxazolones 3a with
nitrosobenzene was next investigated, which could provide the
corresponding polycyclic product 4a in 58% yield with high
regioselecttivity under the mild conditions (Scheme 5).
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 3
Please do not adjust margins

Org aP nl ei ca s &e dB oi o nmo to al ed cj uu sl at rm Ca hr ge imn si stry
Page 4 of 7
ARTICLE
Journal Name
Preparation of terminal ynamides
Procedure A
according to Hofmeister’s procedure.
View Article Online
DOI: 10.1039/C7OB00381A
1-bromo-2-triisopropylsilylacetylene was prepared
:
20
A
solution of
ethynyltriisopropylsilane (50 mmol) in acetone (60 mL) is treated at
rt with N-bromosuccinimide (NBS, 55 mmol) and AgNO (2.5 mmol).
3
After 2h, the reaction mixture is concentrated in vacuum. The crude
products were purified by silica gel flash chromatography on a silica
gel column with petroleum ether (PE) as eluent to afford the 1-
bromo-2-triisopropylsilylacetylene.
Procedure B: TIPS-substituted ynamides were prepared according
2
1
to a modified version of Hsung’s procedure. To a stirred solution
of the appropriate amide (1.0 equiv, 1.0 M in toluene) were added
K PO (2.0 equiv), CuSO •5H O (10 mol%), 1,10-phenanthroline (20
3
4
4
2
mol%) and 1-bromo-2-triisopropylsilylacetylene (1.25 equiv). The
reaction was capped under a blanket of nitrogen and heated at 85
o
C for 48 h while monitored with TLC analysis. Upon completion,
the reaction mixture was cooled to room temperature and diluted
with EtOAc and filtered through celite, and the filtrate was
concentrated in vacuum. The crude products were purified by silica
gel flash chromatography on a silica gel column with petroleum
ether (PE) and ethyl acetate (EA) as eluent to afford directing
products.
Scheme 6. Proposed Mechanism for This Transformation.
Conclusions
In summary, we have developed a one-pot procedure for
synthesis of 5-vinyloxazolones from readily available terminal
ynamides by Pd/Cu-catalyzed tandem head-to-tail dimerization/
cycloisomerization. This method not only comprehensively reported
the cyclization of terminal ynamides to oxazolones for the first time,
but also tolerated a wide range of functional groups on the ynamide
components under Pd/Cu cooperative conditions. The application
of this protocol toward the synthesis of polycyclic oxazolones based
on Diels-Alder reaction was also demonstrated. Further studies to
find more efficient metal-catalyzed functionalization of ynamides
for the synthesis of significant heterocyclic compounds are
underway.
Procedure C: Terminal ynamides 1a-1p were prepared by the
1
7
modified version of Oestreich’s procedure. To a stirred solution of
the appropriate TIPS-substituted ynamide (1.0 equiv, 0.2 M in THF)
cooled to 0 °C was added a solution of TBAF (1.2 equiv, 1.0 M in
THF). After 1h stirring at 0 °C, the reaction was allowed to warm to
room temperature and then quenched with sat. aq. NH Cl. The
4
aqueous layer was extracted with Et O (x 3). The combined organics
2
were washed with brine (x 2), dried (Na SO ), filtered and the
2
4
solvents were evaporated under reduced pressure to afford the
crude product 1a-1p.
tert-butyl ethynyl(4-fluorophenyl)carbamate (1j)
:
Yellow oil; Rf
0
7
.25 (v /v = 60:1); 1H NMR (400 Hz, CDCl ) δ 7.43-7.40 (m, 2 H),
.08-7.03 (m, 2 H), 2.87(s, 1 H), 1.53 (s, 9 H); 13C NMR (100 Hz,
PE EA
3
CDCl ) δ 161.1 (d, J = 244.6 Hz), 153.1 (d, J = 2.6 Hz), 126.7 (d, J = 8.8
Acknowledgements
We greatly acknowledge financial support by the National Key
Research and Development Program of China (No.
3
Hz), 115.7 (d, J = 22.8 Hz), 83.9, 58.3, 27.9; HRMS (ESI) exact mass
calcd for C H FNO [M + Na]+ m/z 258.0906, found 258.0916.
13
14
2
General Procedure for 5-vinyloxazolones
2
016YFB0301703) and the Natural Science Foundation of Jiangsu
Terminal ynamides 1 (0.3 mmol), Pd(PPh ) Cl (0.015 mmol), CuI
Province, China (No. BK20140937).
3 2
2
(
0.03 mmol), P(Cy) (0.03 mol), DIPEA (0.6 mmol), and THF (2.0 mL)
3
were placed into a 10 mL Schlenk tube, and then the temperature
was heated to 65 °C. The solution was stirred under an N2
atmosphere for 18-45 h and monitored by TLC. After being cooled
to room temperature, the reaction mixture was quenched with
ethyl acetate (15 mL) and washed with water (30 mL). The aqueous
phase was extracted twice with EtOAc (3 × 10 mL), and the
Experimental
General Methods
All reactions were performed in reaction tubes under nitrogen
1
13
atmosphere. H NMR and C NMR were recorded at, respectively,
00 and 100 MHz using CDCl3 as solvent. The following
4
combined organic layer was dried over anhydrous Na SO . After
abbreviations are used to describe peak patterns where appropriate:
b = broad, s = singlet, d = doublet, t = triplet, q = quartet, m =
multiplet, dd = doublet of doublets, dt = doublet of triplets.
Coupling constants are reported in hertz (Hz). Chemical shifts are
2
4
evaporation of the solvents under vacuum, the crude products were
purified by flash chromatography on a silica gel column with
petroleum ether (PE) and ethyl acetate (EA) as the eluent to afford
the desired product.
reported in ppm relative to the internal standard tetramethylsilane
1
(
δ = 0 ppm) for HNMR and deuteriochloroform (δ = 77.00 ppm) for di-tert-Butyl
but-3-en-1-yne-1,3-diylbis(phenylcarbamate)
1
3
o
C NMR. High-resolution mass spectra (HRMS) were recorded on (2a)
:
yield 63% (42.9 mg); yellow solid; mp 89-90 C (n-
1
an ESI-TOF (time-of-flight) mass spectrometer. Melting points were hexane/ethyl acetate); R 0.25 (v /v = 15:1); H NMR (400 Hz,
f
PE EA
measured with a micro melting point apparatus.
CDCl ) δ 7.34-7.27 (m, 8 H), 7.23-7.17 (m, 2 H), 5.40 (s, 1 H), 5.32 (s,
3
4
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 5 of 7
Org aP nl ei ca s &e dB oi o nmo to al ed cj uu sl at rm Ca hr ge imn si stry
Journal Name
ARTICLE
1
3
13
1
1
1
2
6
4
H), 1.52 (s, 9 H), 1.43 (s, 9H); C NMR (100 Hz, CDCl ) δ 153.0, H), 1.49 (s, 9 H); C NMR (100 Hz, CDCl ) δ 163.0 (d, J = 246.7 Hz),
3
3
View Article Online
DOI: 10.1039/C7OB00381A
52.5, 141.8, 139.1, 130.0, 128.7, 128.6, 128.5, 126.6, 126.5, 126.0, 162.7 (d, J = 244.3 Hz), 152.8, 151.6, 142.7 (d, J = 9.3 Hz), 137.8,
24.3, 117.1, 83.6, 82.8, 81.2, 68.3, 28.1, 27.9; IR ν (KBr, cm ) 2975, 136.4 (d, J = 9.8 Hz), 134.1, 130.8 (d, J = 8.9 Hz), 129.9 (d, J = 9.0 Hz),
927, 2852, 2241, 1716, 1595, 1495, 1368, 1301, 1250, 1152, 757, 119.6 (d, J = 2.8 Hz), 115.9 (d, J = 3.5 Hz), 115.0, 113.7 (d, J = 20.8
−
1
+
91; HRMS (ESI) exact mass calcd for C H N O [M + Na] m/z Hz), 112.6 (d, J = 21.4 Hz), 111.7 (d, J = 24.5 Hz), 110.5, 108.4 (d, J =
26 30 2 6
−
1
57.2103, found 457.2107.
25.3 Hz), 82.6, 28.1; IR ν (KBr, cm ) 3136, 3005, 2981, 1775, 1709,
tert-Butyl
phenyl)carbamate (3a): yield 62% (34.9 mg); yellow oil; R 0.25 exact mass calcd for C H F N O [M + Na] m/z 437.1289, found
f 22 20 2 2 4
(1-(2-oxo-3-phenyl-2,3-dihydrooxazol-5-yl)vinyl) 1614, 1591, 1498, 1371, 1335, 1223, 1169, 780, 711; HRMS (ESI)
+
(
1
(
v /v = 15:1); H NMR (400 Hz, CDCl ) δ 7.49 (d, J = 7.6 Hz, 2 H), 437.1319.
PE EA 3
7
.44 (t, J = 7.6 Hz, 2 H), 7.39-7.26 (m, 5 H), 7.21-7.14 (m, 1 H), 6.77 tert-Butyl(3-chlorophenyl)(1-(3-(3-chlorophenyl)-2-oxo-2,3-
13
(
s, 1 H), 5.79 (s, 1 H), 5.31 (s, 1 H), 1.48 (s, 9 H); C NMR (100 Hz, dihydrooxazol-5-yl)vinyl)carbamate (3f)
:
yield 59% (79.6 mg);
1
CDCl ) δ 153.2, 152.0, 141.3, 137.8, 135.1, 134.6, 129.5, 128.9, yellow oil; R 0.25 (v /v = 15:1); H NMR (400 Hz, CDCl ) δ 7.56 (t,
3
f
PE EA
3
−1
1
3
6
4
26.8, 125.8, 124.7, 121.0, 114.0, 111.1, 82.0, 28.1; IR ν (KBr, cm ) J = 2.0 Hz, 1 H), 7.42-7.38 (m, 2 H), 7.35 (d, J = 8.0 Hz, 1 H), 7.29-
139, 2986, 2927, 1779, 1698, 1594, 1494, 1358, 1163, 1065, 758, 7.25 (m, 3 H), 7.19-7.13 (m, 1 H), 6.75 (s, 1 H), 5.83 (s, 1 H), 5.33 (d,
+
13
70; HRMS (ESI) exact mass calcd for C H N O [M + Na] m/z J = 0.8 Hz, 1 H), 1.48 (s, 9 H); C NMR (100 Hz, CDCl ) δ 152.7, 151.6,
22
22
2
4
3
01.1477, found 401.1502.
142.3, 137.9, 136.1, 135.3, 134.4, 134.1, 130.5, 129.8, 127.0, 125.8,
−1
tert-Butyl (1-(2-oxo-3-(o-tolyl)-2,3-dihydrooxazol-5-yl)vinyl) 124.4, 122.4, 121.0, 118.7, 115.0, 110.5, 82.6, 28.1; IR ν (KBr, cm )
(
o-tolyl)carbamate (3b)
:
yield 52% (63.5 mg); yellow oil; R 0.25 3127, 2978, 2928, 2835, 1779, 1731, 1594, 1484, 1368, 1232, 1157,
f
1
+
(
v /v = 15:1); H NMR (400 Hz, CDCl ) δ 7.34-7.18 (m, 8 H), 6.62 (s, 777, 681; HRMS (ESI) exact mass calcd for C H Cl N O [M + K]
PE EA 3 22 20 2 2 4
1
1
1
1
2
7
4
H), 5.50 (s, 1 H), 4.99 (d, J = 0.8 Hz, 1 H), 2.32 (s, 3 H), 2.30 (s, 3 H), m/z 485.0437, found 485.0857.
13
.44 (s, 9 H); C NMR (100 Hz, CDCl ) δ 153.0, 152.7, 140.8, 137.9, tert-Butyl(3-bromophenyl)(1-(3-(3-bromophenyl)-2-oxo-2,3-
3
35.6, 135.3, 135.0, 133.6, 131.5, 131.1, 129.2, 127.4, 127.1, 127.0, dihydrooxazol-5-yl)vinyl)carbamate (3g)
:
yield 48% (76.7 mg);
−
1
1
26.7, 113.4, 110.1, 81.5, 28.1, 18.1, 17.8; IR ν (KBr, cm ) 3112, yellow oil; R 0.25 (v /v = 15:1); H NMR (400 Hz, CDCl ) δ 7.70 (t,
f
PE EA
3
978, 2929, 1780, 1679, 1614, 1498, 1598, 1453, 1367, 1227, 1159, J = 1.6 Hz, 1 H), 7.56 (t, J = 1.6 Hz, 1 H), 7.47-7.40 (m, 2 H), 7.31 (d, J
+
53; HRMS (ESI) exact mass calcd for C H N O [M + Na] m/z = 8.4 Hz, 3 H), 7.20 (t, J = 7.6 Hz, 1 H), 6.75 (s, 1 H), 5.83 (s, 1 H),
24 26 2 4
13
29.1790, found 429.1787.
5.33 (s, 1 H), 1.48 (s, 9 H); C NMR (100 Hz, CDCl ) δ 152.7, 151.5,
3
tert-butyl (1-(2-oxo-3-(m-tolyl)-2,3-dihydrooxazol-5-yl)vinyl) 142.5, 137.8, 136.2, 134.1, 130.7, 130.0, 129.9, 128.8, 127.3, 123.8,
−
1
(
(
m-tolyl)carbamate (3c): yield 48% (59.7 mg); yellow oil; R 0.25 123.0, 122.9, 122.3, 119.3, 115.0, 110.5, 82.6, 28.1; IR ν (KBr, cm )
f
1
v /v = 15:1); H NMR (400 Hz, CDCl ) δ7.33-7.15 (m, 6 H), 7.10 (d, 3128, 2977, 2928, 1769, 1730, 1588, 1517, 1481, 1369, 1232, 1156,
PE EA 3
J = 7.6 Hz, 1 H), 7.00 (d, J = 7.2 Hz, 1 H), 5.76 (s, 1 H), 5.28 (s, 1 H), 871, 776, 679; HRMS (ESI) exact mass calcd for C H Br N O [M +
22
20
2 2 4
1
3
+
2
1
1
2
1
.38 (s, 3 H), 2.34 (s, 3 H), 1.48 (s, 9 H); C NMR (100 Hz, CDCl ) δ Na] m/z 556.9688, found 556.9712.
3
53.3, 152.2, 141.3, 139.7, 138.8, 137.9, 135.2, 134.9, 129.3, 128.6, tert-Butyl(1-(2-oxo-3-(3-(trifluoromethyl)phenyl)-2,3-
27.6, 126.7, 125.3, 121.9, 121.7, 118.1, 113.7, 111.3, 81.8, 28.2, dihydrooxazol-5-yl)vinyl)(3-(trifluoromethyl)phenyl)
−
1
o
1.5, 21.4; IR ν (KBr, cm ) 2976, 2924, 2853, 1771, 1714, 1607, carbamate (3h)
: yield 48% (76.7 mg); yellow solid; mp 121-122 C
1
493, 1368, 1324, 1159, 866, 779, 691; HRMS (ESI) exact mass calcd (n-hexane/ethyl acetate); R 0.25 (v /v = 15:1); H NMR (400 Hz,
f
PE EA
+
for C H N O [M + Na] m/z 429.1790, found 429.1829.
CDCl ) δ 7.77 (s, 1 H), 7.74 (dt, J = 2.0 Hz, J = 3.6 Hz, 1 H), 7.67 (s, 1
3 1 2
24
26
2
4
tert-Butyl(3-methoxyphenyl)(1-(3-(3-methoxyphenyl)-2-oxo-
H), 7.60-7.54 (m, 3 H), 7.49-7.44 (m, 2 H), 6.81 (s, 1 H), 5.88 (s, 1 H),
13
2
,3-dihydrooxazol-5-yl)vinyl)carbamate (3d) yield 65% (88.4 5.36 (s, 1 H), 1.49 (s, 9 H); C NMR (100 Hz, CDCl ) δ 152.7, 151.6,
:
3
1
mg); yellow oil; R 0.25 (v /v = 15:1); H NMR (400 Hz, CDCl ) δ 141.8, 138.0, 135.6, 134.1, 132.2 (d, J = 32.6 Hz), 131.4 (d, J = 32.4
f
PE EA
3
7
.32 (t, J = 8.4 Hz, 1H), 7.23 (d, J = 8.0 Hz, 1 H), 7.13 (t, J = 2.0 Hz, 1 Hz), 130.3, 129.5, 127.3, 125.0 123.9, 123.45 (m), 123.4 (d, J = 271.6
H), 7.01 (dd, J = 2.0 Hz, J = 8.0 Hz, 1 H), 6.96 (dd, J =1.6 Hz, J = 7.6 Hz), 122.3 (m), 121.2 (d, J = 4.8 Hz), 117.6 (q, J = 4.0 Hz), 115.4,
1
2
1
2
−
1
Hz, 1 H), 6.93 (t, J = 1.6 Hz, 1 H), 6.82 (dd, J = 2.4 Hz, J =8.4 Hz, 1 H), 110.4, 82.9, 28.1; IR ν (KBr, cm ) 3148, 2980, 1794, 1710, 1593,
1
2
6
.76 (s, 1 H), 6.73 (dd, J = 2.4 Hz, J = 8.4 Hz, 1 H), 5.78 (s, 1 H), 5.30 1496, 1465, 1332, 1255, 1120, 792, 696; HRMS (ESI) exact mass
1 2
13
+
(
s, 1 H), 3.81 (d, J = 11.2 Hz, 6 H), 1.48 (s, 9 H); C NMR (100 Hz, calcd for C H F N O [M + Na] m/z 537.1225, found 537.1259.
24 20 6 2 4
CDCl ) δ 160.3, 159.9, 153.1, 151.9, 142.4, 137.7, 136.2, 134.6, tert-Butyl (1-(2-oxo-3-(p-tolyl)-2,3-dihydrooxazol-5-yl)vinyl)
3
1
8
1
30.2, 129.4, 117.0, 114.0, 112.8, 112.3, 111.1, 110.9, 110.8, 107.0, (p-tolyl)carbamate (3i): yield 46% (56.4 mg); yellow oil; R 0.25
f
−
1
1
1.9, 55.5, 55.3, 28.1; IR ν (KBr, cm ) 2975, 2933, 2837, 1770, 1715, (v /v = 15:1); H NMR (100 Hz, CDCl ) δ 7.36 (d, J = 8.4 Hz, 3 H),
PE EA
3
603, 1495, 1456, 1368, 1320, 1164, 1046, 771, 705; HRMS (ESI) 7.24-7.20 (m, 4 H), 7.12 (d, J = 8.0 Hz, 3 H), 6.73 (s, 1 H), 5.75 (s, 1 H),
+
13
exact mass calcd for C H N O [M + Na] m/z 461.1689, found 5.28 (s, 1 H), 2.36 (s, 3 H), 2.32 (s, 3 H), 1.47 (s, 9 H); C NMR (100
2
4 26 2 6
4
61.1720.
Hz, CDCl ) δ 153.4, 152.2, 138.8, 137.7, 136.8, 135.7, 134.9, 132.7,
3
tert-Butyl (3-fluorophenyl)(1-(3-(3-fluorophenyl)-2-oxo-2,3- 130.0, 129.4, 124.7, 121.0, 113.5, 111.4, 81.7, 28.2, 20.9, 20.8; IR ν
−
1
dihydrooxazol-5-yl) vinyl)carbamate (3e): yield 56% (69.5 mg); (KBr, cm ) 2976, 2925, 1765, 1713, 1613, 1514, 1367, 1253, 1161,
o
+
yellow solid, mp 145-146 C (n-hexane/ethyl acetate); R 0.25 816; HRMS (ESI) exact mass calcd for C H N O [M + Na] m/z
(
f
24 26 2 4
1
v /v = 15:1); H NMR (400 Hz, CDCl ) δ 7.40 (dd, J =2.0 Hz, J = 437.1289, found 437.1320.
PE EA 3 1 2
8
.0 Hz, 1 H), 7.36 (td, J =2.0 Hz, J = 10.0 Hz, 1 H), 7.32 -7.24 (m, 2 tert-Butyl(4-fluorophenyl)(1-(3-(4-fluorophenyl)-2-oxo-2,3-
1 2
H), 7.16 (d, J = 7.6 Hz, 2 H), 6.99 (dt, J = 2.4 Hz, J = 8.0 Hz,1 H), 6.89 dihydrooxazol-5-yl)vinyl)carbamate (3j): yield 70% (87.6 mg);
1
2
1
(
dt, J = 1.6 Hz, J = 6.8 Hz, 1 H), 6.75 (s, 1 H), 5.84 (s, 1 H), 5.34 (s, 1 yellow oil; R 0.25 (v /v = 15:1); H NMR (400 Hz, CDCl ) δ 7.49-
1
2
f
PE EA
3
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 5
Please do not adjust margins

Org aP nl ei ca s &e dB oi o nmo to al ed cj uu sl at rm Ca hr ge imn si stry
Page 6 of 7
ARTICLE
Journal Name
7
8
.45 (m, 2 H), 7.34-7.30 (m, 2 H), 7.13 (t, J = 8.4 Hz, 2 H), 7.03 (t, J = 146.5, 145.8, 137.4, 135.3, 135.0, 129.2, 118.6, 115.0, 113.3, 111.8,
View Article Online
13
−1
DOI: 10.1039/C7OB00381A
.4 Hz, 2 H), 6.72 (s, 1 H), 5,77 (s, 1 H), 5.29 (s, 1 H), 1.47 (s, 9 H);
C
108.4, 107.9, 107.0, 103.7, 101.8, 101.5, 81.8, 28.1; IR ν (KBr, cm )
NMR (100 Hz, CDCl ) δ 161.0 (d, J = 246.4 Hz), 160.4 (d, J = 243.6 Hz), 2981, 2934, 1804, 1719, 1598, 1495, 1372, 1338, 1104, 757; HRMS
3
+
1
1
1
2
1
53.2, 152.1, 137.7, 137.3 (d, J = 3.1 Hz), 134.6, 131.1 (d, J = 3.2 Hz), (ESI) exact mass calcd for C H N O [M + Na] m/z 489.1274,
24 22 2 8
26.5 (d, J = 8.9 Hz), 123.1 (d, J = 9.1 Hz), 116.4 (d, J = 23.3 Hz), found 489.1274.
−
1
15.7 (d, J = 22.5 Hz), 114.1, 111.2, 82.1, 28.1; IR ν (KBr, cm ) 3144, tert-Buty lnaphthalen-2-yl(1-(3-(naphthalen-2-yl)-2-oxo-2,3-
988, 2928, 1770, 1703, 1606, 1509, 1458, 1368, 1330, 1226, 1159, dihydrooxazol-5-yl) vinyl) carbamate (3p) yield 66% (121.8 mg);
120, 1066, 835; HRMS (ESI) exact mass calcd for C H F N O [M + colorless oil; R 0.25 (v /v = 15:1); H NMR (400 Hz, CDCl ) δ 7.94
:
1
22
20
2
2
4
f
PE EA
3
+
Na] m/z 437.1289, found 437.1320.
tert-Butyl(4-chlorophenyl)(1-(3-(4-chlorophenyl)-2-oxo-2,3-
dihydrooxazol-5-yl)vinyl)carbamate (3k) yield 68% (90.9 mg);
(d, J = 2.0 Hz, 1 H), 7.88 (d, J = 8.8 Hz, 1 H), 7.85-7.77 (m, 6 H), 7.62-
7.42 (m, 6 H), 6.93 (s, 1 H), 5.87 (s, 1 H), 5.39 (s, 1 H), 1.52 (s, 9 H);
13
:
C NMR (100 Hz, CDCl ) δ 153.4, 152.2, 138.9, 138.0, 134.8, 133.5,
3
o
yellow solid; mp 167-168 C (n-hexane/ethyl acetate); R 0.25 133.3, 132.5, 131.7, 131.4, 129.6, 128.6, 127.9, 127.7, 127.5, 127.1,
f
1
(
v /v = 15:1); H NMR (400 Hz, CDCl ) δ 7.48-7.38 (m, 4 H), 7.30 (s, 126.5, 126.4, 125.9, 123.8, 122.0, 119.4, 119.0, 114.2, 111.4, 82.2,
PE EA
3
13
−1
4
H), 6.71 (s, 1 H), 5.81 (s, 1 H), 5.31 (s, 1 H), 1.47 (s, 9 H); C NMR 31.6, 28.2, 22.7, 14.1; IR ν (KBr, cm ) 3128, 2978, 2929, 1735, 1692,
(
1
100 Hz, CDCl ) δ 152.9, 151.7, 139.8, 137.8, 134.3, 133.6, 132.4, 1599, 1545, 1368, 1230, 1162, 1056, 814, 743; HRMS (ESI) exact
3
+
31.2, 129.6, 129.0, 125.7, 122.1, 114.6, 110.7, 82.4, 28.1; IR ν (KBr, mass calcd for C H N O [M + Na] m/z 501.1790, found 501.1788.
30 26 2 4
−
1
cm ) 3148, 3000, 2979, 2920, 1764, 1704, 1598, 1499, 1458, 1367, Diels-Alder reaction of 5-vinyloxazolone 3a
1
324, 1159, 1076, 832; HRMS (ESI) exact mass calcd for
In a 10 mL flame-dried Schlenk tube under air condition, tert-
Butyl (1-(2-oxo-3-phenyl-2, 3-dihydrooxazol-5-yl)vinyl)(phenyl)
carbamate 3a (0.3 mmol) and nitrosobenzene (0.33 mmol) were
dissolved in toluene (2.0 mL). Then the reaction solution was kept
stirring for 12 h under air condition and monitored by TLC. Upon
completion, the reaction mixture was filtered and the filtrate was
concentrated in vacuum to give a crude product, which was purified
by silica gel column chromatography to afford tert-butyl(6-oxo-
+
C H Cl N O [M + Na] m/z 469.0698, found 469.0722.
tert-Butyl(4-bromophenyl)(1-(3-(4-bromophenyl)-2-oxo-2,3-
dihydrooxazol-5-yl)vinyl)carbamate (3l) yield 63% (101.2 mg);
22
20
2 2 4
:
o
yellow solid; mp 122-123 C (n-hexane/ethyl acetate); R 0.25
f
1
(
v /v = 15:1); H NMR (400 Hz, CDCl ) δ 7.56 (d, J = 8.8 Hz, 2
PE EA
3
H),7.44 (d, J = 8.4 Hz, 2 H), 7.39 (d, J = 9.2 Hz, 2 H), 7.25 (d, J = 8.8 Hz,
2
13
H), 6.71 (s, 1 H), 5.81 (s, 1 H), 5.31 (s, 1 H), 1.47 (s, 9 H); C NMR
(
100 Hz, CDCl ) δ 152.8, 151.6, 140.3, 137.8, 134.2, 134.1, 132.6,
3
2
,7-diphenyl-3,6,7,7a-tetrahydro-2H-oxazolo [5, 4e] [1,2]
oxazin-4-yl)(phenyl) carbamate 4a): yield 58% (70.2 mg); yellow
oil; R 0.25 (v /v = 10:1); H NMR (400 Hz, CDCl ) δ 7.67 (d, J = 7.6
1
32.0, 126.0, 122.3, 120.2, 119.0, 114.8, 110.6, 82.5, 28.1; IR ν (KBr,
(
−
1
cm ) 3152, 3119, 2983, 2966, 2927, 1791, 1703, 1591, 1489, 1454,
368, 1327, 1162, 1061, 823; HRMS (ESI) exact mass calcd for
1
f
PE EA
3
1
Hz, 2 H), 7.47 (t, J = 7.6 Hz, 2 H), 7.40-7.23 (m, 7 H), 7.10-7.04 (m, 3
+
C H Br N O [M + Na] m/z 556.9688, found 556.9721.
tert-Butyl
yl)vinyl)carbamate (3m)
22
20
2 2 4
H), 6.37 (t, J = 2.4 Hz, 1 H), 4.28 (d, J = 14.0 Hz, 1 H), 3.88 (dd, J =
1
benzyl(1-(3-benzyl-2-oxo-2,3-dihydrooxazol-5-
yield 42% (51.4 mg); yellow oil; R 0.25
13
2
1
1
.4 Hz, J = 14.4 Hz, 1 H), 1.51 (s, 9 H); C NMR (100 Hz, CDCl ) δ
2
3
:
f
52.4, 151.0, 148.4, 139.5, 139.1, 135.9, 129.4, 129.1, 126.6, 126.5,
25.9, 123.7, 121.0, 116.0, 113.6, 85.6, 82.2, 54.5, 28.1; IR ν (KBr,
1
(
v /v = 15:1); H NMR (400 Hz, CDCl ) δ 7.40-7.30 (m, 4 H), 7.25-
PE EA 3
7
4
1
1
1
.17 (m, 6 H), 5.92 (s, 1 H), 5.43 (s ,1 H), 4.91 (s, 1 H), 4.64 (s, 2 H),
cm−1) 2976, 2925, 1802, 1749, 1694, 1599, 1492, 1351, 1298, 1120,
13
.53 (s, 2 H), 1.32 (s, 9 H); C NMR (100 Hz, CDCl ) δ 154.6, 154.3,
+
3
7
5
53; HRMS (ESI) exact mass calcd for C H N O [M + Na] m/z
28 27 3 5
08.1848, found 508.1882.
38.0, 137.2, 135.0, 134.7, 129.0, 128.4, 128.3, 128.0, 127.6, 111.3,
−
1
11.0, 80.9, 53.1, 47.7, 28.1; IR ν (KBr, cm ) 3127, 2980, 2928, 1760,
684, 1603, 1497, 1454, 1367, 1352, 1161, 1128, 1065, 737, 699;
+
HRMS (ESI) exact mass calcd for C H N O [M + Na] m/z 429.1790,
24
26
2
4
Notes and references
found 429.1818.
tert-Butyl(4-methoxybenzyl)(1-(3-(4-methoxybenzyl)-2-oxo-
,3-dihydrooxazol-5-yl)vinyl)carbamate (3n) yield 34% (49.8
mg); yellow oil; R 0.25 (v /v = 15:1); H NMR (400 Hz, CDCl ) δ
1
a) J.-C. Wasilke, S. J. Obrey, R. T. Baker and G. C. Bazan, Chem.
Rev., 2005, 105, 1001;
2
:
2
For reviews, see: a) J. A. Mata, F. E. Hahn and E. Peris, Chem. Sci.,
2014, 5, 1723; b) M. Vilches-Herrera, L. Domke and A. Bꢀrne,
ACS Catal., 2014, 4, 1706; c) C. Robert and C. M. Thomas, Chem.
Soc. Rev., 2013, 42, 9392; d) J. Zhou, Chem. Asian J., 2010, 5,
1
f
PE EA
3
7
2
.19-7.12 (m, 4 H), 6.88 (dt, J = 2.0 Hz, J = 8.8 Hz,2 H), 6.78 (dt, J =
1 2 1
.0 Hz, J = 8.8 Hz, 2 H), 5.91 (s, 1 H), 5.42 (s, 1 H), 4.87 (s, 1 H), 4.58
2
4
22; e) N. Shindoh, Y. Takemoto and K. Takasu, Chem. Eur. J.,
009, 15, 12168.
13
(
s, 2 H), 4.46 (s, 2 H), 3.81 (s, 3 H), 3.78 (s, 3 H), 1.32 (s, 9 H);
C
2
NMR (100 Hz, CDCl ) δ 159.7, 159.0, 154.5, 154.2, 137.2, 134.6,
3
4
a) C.-H. Shen, L. Li, W. Zhang, S. Liu, C. Shu, Y.-E. Xie, Y.-F. Yu and
L.-W. Ye, J. Org. Chem., 2014, 79, 9313; b) M. R. Fructos, E.
Álvarez, M. M. Díaz-Requejo and P. R. Pérez, J. Am. Chem. Soc.,
3
1
5
1
30.2, 129.8, 129.4, 127.0, 114.4, 113.7, 111.3, 110.8, 80.7, 55.3,
−
1
5.2, 52.4, 47.3, 28.1; IR ν (KBr, cm ) 2933, 2837, 1768, 1699, 1611,
2
010, 132, 4600; c) K. A. Cannon, M. E. Geuther, C. K. Kelly, S.
514, 1456, 1367, 1249, 1175, 1033, 819, 765; HRMS (ESI) exact
Lin and A. H. R. MacArthur, Organometal., 2011, 30, 4067; d) Z.
Ye, F. AlObaidi, S. Zhu and R. Subramanian, Macromol. Chem.
Phys., 2005, 206, 2096.
+
mass calcd for C H N O [M + Na] m/z 489.2002, found 489.2038.
26 30 2 6
tert-Butylbenzo[d][1,3]dioxol-5-yl ](1-(3-(benzo[d][1,3]dioxol-
-yl)-2-oxo-2,3-dihydrooxazol-5-yl)vinyl)carbamate (3o) yield
8% (66.2 mg); yellow oil; R 0.25 (v /v = 15:1); H NMR (400 Hz,
5
4
:
O. Wink, E. Dorn and K. Beyermann, J. Agric. Food Chem., 1984,
1
3
2, 187.
f
PE EA
5
6
J. Jagatheeswari, J. Aquatic Biology, 2004, 19, 155.
CDCl ) δ 7.04 (d, J = 2.0 Hz, 1 H), 6.88-6.82 (m, 3 H), 6.80-6.72 (m, 2
H), 6.68 (s, 1 H), 6.00 (s, 2 H), 5.97 (s, 2 H), 5.71 (s, 1 H), 5.26 (s, 1 H),
1
3
S. J. Brickner, D. K. Hutchinson, M. R. Barbachyn, P. R. Manninen,
D. A. Ulanowicz, S. A. Garmon, K. C. Grega, S. K. Hendges, D. S.
Toops, C. W. Ford and G. E. Zurenko, J. M. Chem., 1996, 39, 673.
13
.46 (s, 9 H); C NMR (100 Hz, CDCl ) δ 153.4, 152.2, 148.3, 147.8,
3
6
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 7 of 7
Org aP nl ei ca s &e dB oi o nmo to al ed cj uu sl at rm Ca hr ge imn si stry
Journal Name
ARTICLE
7
8
N. Kudo, M. Taniguchi, S. Furuta, K. Sato, T. Endo and T. Honma,
View Article Online
DOI: 10.1039/C7OB00381A
J. Agric. Food Chem., 1998, 46, 5305.
For selected examples, see: a) M. Yamashita, S. H. Lee, G. Koch,
J. Zimmermann, B. Clapham and K. D. Janda, Tetrahedron Lett.,
2005, 46, 5495; b) H. F. Jiang, J. W. Zhao and A. Z. Wang,
Synthesis, 2008, 5, 763; c) M. O. Hamad, P. K. Kiptoo, A. L.
Stinchcomb and P. A. Crooks, Biorg. Med. Chem., 2006, 14, 7051;
d) C. A. Marques, M. Selva, P. Tundo and F. Montanari, J. Org.
Chem., 1993, 58, 5765; e) H. Aichaoui, J. H. Poupaert, D. Lesieur
and J. P. Henichart, Tetrahedron, 1991, 47, 6649; f) R. N. Ram
and V. K. Soni, J. Org. Chem., 2013, 78, 11935; g) K. Fujita, J.
Sato, A. Fujii, S. Onozawa and H. Yasuda, Asian J. Org. Chem.,
2
016, 5, 828; h) J. Hu, J. Ma, Z. Zhang, Q. Zhu, H. Zhou, W. Lu
and B. Han, Green Chem., 2015, 17, 1219.
9
1
F. M. Istrate, A. K. Buzas, I. D. Jurberg, Y. Odabachian and F.
Gagosz, Org. Lett., 2008, 10, 925.
0 a) Z. Lu, W. Cui, S. Xia, Y. Bai, F. Luo and G. Zhu, J. Org. Chem.
2012, 77, 9871; b) Z. Lu, X. Xu, Z. Yang, Y. Kong and G. Zhu,
Tetrahedron Lett., 2012, 53, 3433; c) Z. Lu, Z. Yang, W. Cui and G.
Zhu, Chem. Lett., 2012, 41, 636; d) A. S. K. Hashmi, R. Salathé
and W. Frey, Synlett, 2007, 1763.
1
1 H. Huang, G. He, G. Zhu, S. Qi and H. Zhu, J. Org. Chem., 2015,
80, 3480.
1
2 a) H. Huang, L. Tang, X. Han, G. He, Y. Xi and H. Zhu, Chem.
Commun., 2016, 52, 4321; b) H. Huang, L. Tang, Q. Liu, Y. Xi, G.
He and H. Zhu, Chem. Commun., 2016, 52, 5605; c) H. Huang, J.
Fan, G. He, Z. Yang, X. Jin, Q. Liu and H. Zhu, Chem. Eur. J., 2016,
22, 2532; d) H. Huang, X. Zhu; G. He, Q. Liu, J. Fan and H. Zhu,
Org. Lett., 2015, 17, 2510; e) H. Huang, L. Tang, Y. Xi, G. He and
H. Zhu, Tetrahedron Lett., 2016, 57, 1873; f) A. S. Reddy, and K.
C. K. Swamy, Org. Lett. 2015, 17, 2996; g) F.-X. Felpin, and E.
Fouquet, Chem. Eur. J. 2010, 16, 12440; h) D. Fujino, H.
Yorimitsu, and A. Osuka, J. Am. Chem. Soc. 2014, 136, 6255; i) X.
Zhang, Y. Zhang, J. Huang, R. P. Hsung, K. C. M. Kurtz, J.
Oppenheimer, M. E. Petersen, I. K. Sagamanova, L. Shen, and M.
R. Tracey, J. Org. Chem. 2006, 71, 4170; j) M. Lecomte, and G.
Evano, Angew. Chem. Int. Ed. 2016, 55, 4547; k) A. S. Reddy, A. L.
S. Kumari, S. Saha, and K. C. K. Swamy, Adv. Synth. Catal. 2016,
3
58,1625.
1
3 a) S. Saito, N. Uchiyama, V. Gevorgyan and Y. Yamamoto, J. Org.
Chem. 2000, 65, 4338; b) M. R. Tracey, Y. Zhang, M. O. Frederick,
J. A. Mulder and R. P. Hsung, Org. Lett. 2004, 6, 2209.
1
4 a) D. I. Chai, L. Hoffmeister and M. Lautens, Org. Lett., 2011, 13,
1
06; b) P. Zhao, D. Chen, G. Song, K. Han and X. Li, J. Org. Chem.
2
012, 77, 1579.
1
1
5 For the details of X-ray single-crystal, see SI.
6 a) B. Lü, C. Fu and S. Ma, Chem. Eur. J., 2010, 16, 6434; b) B. Lü,
C. Fu and S. Ma, Tetrahedron Lett., 2010, 51, 1284.
1
7 E. Romain, C. Fopp, F. Chemla, F. Fer reira, O. Jackowski, M.
Oestreich and A. Perez-Luna, Angew. Chem., Int. Ed., 2014, 53,
11333.
1
8 a) K. A. DeKorver, H. Li, A. G. Lohse, R. Hayashi, Z. Lu, Y. Zhang
and R. P. Hsung, Chem. Rev. 2010, 110, 5064; b) G. Evano, A.
Coste and K. Jouvin, Angew. Chem., Int. Ed., 2010, 49, 2840; c) X.
N. Wang,; H. S. Yeom, L. C. Fang, S. He, Z. X. Ma, B. L. Kedrowski
and R. P. Hsung, Acc. Chem. Res., 2014, 47, 560.
1
9 a) S. S. Ichake, A. Konala, V. Kavala, C. Kuo, and C. Yao, Org. Lett.,
2017, 19, 54; b) C. Zhu, C. Feng and M. Yamane, Chem.
Commun., 2017, 53, 2606; c) L. Zhou, F. Ye, Y. Zhang, and J.
Wang, J. Am. Chem. Soc., 2010, 132, 13590.
0 H. Hofmeister, K. Annen, H. Laurent and R. Wiechert, Angew.
Chem., Int. Ed., 1984, 23, 727.
1 Y. Zhang, R. P. Hsung, M. R. Tracey, K. C. M. Kurtz, and E. L. Vera,
Org. Lett., 2004, 6, 1151.
2
2
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 7
Please do not adjust margins