Palladium (0)-catalyzed C(sp2)-H oxygenation with carboxylic acids

Article abstract of DOI:10.1016/j.tet.2020.130969

Palladium (0)-catalyzed Ortho-benzoxylation of the sp² C–H bond of arylbenzoxazinones with carboxylic acid is reported. With benzoxazinone as directing group, the reaction went smoothly under the benign condition and gave the desired product wi

Full text of DOI:10.1016/j.tet.2020.130969

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2
Palladium (0)-catalyzed C(sp )-H oxygenation with carboxylic acids
Jia-Yuan Yong, Huu-Manh Vu, Xu-Qin Li, Ai-Jun Gong
PII:
S0040-4020(20)30061-2
https://doi.org/10.1016/j.tet.2020.130969
TET 130969
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 6 December 2019
Revised Date: 17 January 2020
Accepted Date: 21 January 2020
2
Please cite this article as: Yong J-Y, Vu H-M, Li X-Q, Gong A-J, Palladium (0)-catalyzed C(sp )-H
oxygenation with carboxylic acids, Tetrahedron (2020), doi: https://doi.org/10.1016/j.tet.2020.130969.
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Palladium (0)-catalyzed C(sp )-H
oxygenation with carboxylic acids
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Jia-Yuan Yong, Huu-Manh Vu, Xu-Qin Li*, Ai-Jun Gong
School of Chemical and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan
Road, Haidian District, Beijing 100083, China.

1
Tetrahedron
journal homepage: www.elsevier.com
2
Palladium (0)-catalyzed C(sp )-H oxygenation with carboxylic acids
Jia-Yuan Yong, Huu-Manh Vu, Xu-Qin Li ∗ , Ai-Jun Gong
School of Chemical and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China
ARTICLE INFO
ABSTRACT
2
Article history:
Received
Received in revised form
Accepted
Palladium (0)-catalyzed Ortho-benzoxylation of the sp C-H bond of arylbenzoxazinones with
carboxylic acid is reported. With benzoxazinone as directing group, the reaction went smoothly
under the benign condition and gave the desired product with excellent ortho selectivity. This
procedure is compatible with a wide range of functional groups without the use of any ligands or
additives. This method provides a straightforward and convenient access to various valuable
acyloxylated products.
Available online
Keywords:
Palladium
C−H benzoxylation
benzoxazinones
carboxylic acid
—
——
∗
Corresponding author. Tel./fax: +86 1062332689; e-mail: lixuqin@ustb.edu.cn

2
Tetrahedron
1
. Introduction
3aa could be increased to 69 % (entry 11). The catalyst was
found to be indispensable to the reaction (entry 14). Several
oxidants were screened (entries 15-19), CAN afforded the best
result than Na S O , K S O , ceric ammonium sulfate (CAS) and
so on. The oxidant was also as essential to the reaction as
catalysts (entry 20), increasing the amount of oxidant had an
adverse effect on the reaction, and the suitable amount of oxidant
was 1.2 equiv (table 1, entries 11, 21-22). Increasing the reaction
temperature the target product yield could be improved to 78 %
In recent years, impressive advances have been made in the
transition-metal-catalyzed C-H functionalization because of its
step economy, atom economy, and environmental sustainability.
By using various catalysts such as palladium, copper, ruthenium,
rhodium and iridium, selective transforming inert C-H bonds to
2
2
8
2
2
8
1
C-C or C-heteroatom bonds has been made great progress. Due
to the prevalence of C-O bond in natural products,
pharmaceuticals, agrochemical, C-H oxygenation especially
acyloxylation towards ester synthesis has attracted considerable
(entry 24). Finally, the use of 1a (0.3 mmol), 2a (0.3 mmol),
Pd(PPh ) (5 mol %), and CAN (0.36 mmol) in DCE (3 mL)
2
3 4
attention. The group of Sanford first reported the acetoxylation
under air was chosen as the standard reaction conditions (entry
of C-H bonds with PhI(OAc)2 as the acetate source and the
2
4).
3a,3b
pyridine group as the directing group.
Inspired by these
studies, direct acetoxylations of C-H bonds in different systems
Table 1. Optimization of C-H benzoxylation reaction
condition
a,b
using PhI(OAc) , anhydride, tert-butyl peroxyacetate, acid halide,
2
and sodium carboxylate as a carboxyl source have been
3
successfully developed. Compared to acetoxylation, the C-H
benzoxylation is less developed. Cheng’s group developed ortho-
2
benzoxylation of sp C-H bond with different starting materials
4a
and benzoxy surrogates. Later a few other benzoxylations have
4
2
also been reported. However, the direct oxygenation of C(sp )-H
bonds with aryl carboxylic acid as an acyl source is still limited.
In view of carboxylic acids are comparatively stable, nontoxic,
and readily available from natural resources, therefore, there is
still a need for complementary methods to attain a broader utility
of this transformation.
b
Entry
1
Catalyst
Pd(OAc)
Pd(OAc)
Pd(OAc)
Pd(OAc)
Pd(OAc)
Pd(OAc)
Pd(OAc)
Pd(OAc)
Pd(TFA)
Oxidant
CAN
CAN
CAN
CAN
CAN
CAN
CAN
CAN
CAN
CAN
CAN
CAN
CAN
CAN
TBHP
Solvent
DCE/CH CN(2:1)
DCE
CH CN
toluene
1,4-dioxane
DMSO
DMF
PhCl
Yield (%)
a
2
2
2
2
2
2
2
2
2
3
21
44
0
0
0
2
3
4
5
6
7
8
9
3
Benzoxazinones scaffold is endowed with intrinsic
coordinating moieties that can promote the metal-catalyzed
0
0
2
regioselective C(sp )-H activation without employing exogenous
31
46
0
60
49
51
0
coordinating moieties or protecting groups, and functionalized 2-
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
DCE
5
arylbenzoxazinones have diverse biological activities (Figure 1).
10
PdCl
Pd(PPh
Pd (dba)
2
c
1
1
1
2
3
)
3
4
Promoted by these, we previously described the successful
development of the C-H halogenation and acetoxylation of 2-
2
6
13
Pd(NO
-
3
)
2
arylbenzoxazinones, in continuation of our research on slective
1
1
4
5
C-H bond functionalization, we report here the first ortho-
selective C-H benzoxylation of benzoxazinones with benzoic
acids.
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
Pd(PPh
3
3
3
3
3
3
3
3
3
3
3
)
4
4
4
4
4
4
4
4
4
4
4
0
16
17
)
)
)
)
)
)
)
)
)
)
Na
2
S
2
O
8
Trace
Trace
Trace
0
K
2
S
2
O
8
1
1
2
2
2
2
2
2
8
9
0
1
2
3
4
5
CAS
CeO
-
2
0
d
e
f
CAN
CAN
CAN
CAN
CAN
66
69
53
78
64
g
h
DCE
a
Conditions: 1a (0.3 mmol), 2a (0.3 mmol), catalyst (10 mol %), oxidant
o
b
c
(
0.45 mmol), solvent (3 mL), under air, 110 C,12 h. Isolated yield. catalyst
d
e
f
(
5 mol %). Oxidant (0.3 mmol, 1.0 eq). Oxidant (0.36 mmol, 1.2 eq). 100
o
g o h o
C. 120 C. 130 C.
With the optimized conditions in hand, we then explored the
substrate scope of the C-H oxygenation with variously decorated
benzoxazinones (Table 2). As expected, various substrates
exhibited good monoselectivity under the reaction conditions.
Benzoxazinones (A ring) contain mildly electron-deficient
groups gave better yields (72-76 %) than electron-rich groups
(3ba, 3ca versus 3da-3fa). While the electronic characteristics of
substituents on the 2-aryl ring (B ring) of 2-arylbenzoxazines
have a significant influence on the reaction yields (3ga-3pa). B
ring bearing electron-donating substituent such as methyl,
methoxy groups produced better yields of 3ga and 3ma (63-71
%), whereas the analogous with electron-withdrawing fluoro,
chloro, bromo groups resulted in 38 %-61 % yields. By testing a
series of substrates containing different substitution patterns and
various functional groups, the work further enrich the structural
diversity of the benzoxylation products.
Figure 1. Representative examples of 2-arylbenzoxazinones.
2
. Results and Discussion
Our investigation started with the reaction of benzoic acid (2a)
and 2-phenylbenzoxazinone (1a) in the presence of 10 mol % of
Pd(OAc) and 1.5 equiv of ceric ammonium nitrate (CAN) in a
2
mixed solvent consisting of 1,2-dichlorethane(DCE) and
acetonitrile at 110 °C under air for 12 h. The desired product
(3aa) was afforded in 21 % isolated yield (Table 1, entry 1).
Encouraged by this initial result, we then optimized the reaction
conditions. Among the solvents examined, DCE gave the best
results (entries 2-8), in sharp contrast, there was no reaction
while in CH CN, toluene, 1,4-dioxane, DMSO, or DMF. After
3
that, catalysts optimizing experiments demonstrated that
Pd(PPh ) were much efficient than Pd(OAc) , Pd(TFA) , PdCl ,
3
4
2
2
2
Pd (dba) , and Pd(NO ) (entries 9-13). Remarkably, the yield of
2
3
3 2

3
Table 2. ortho-Benzoxylation Reaction of 2-phenylbenzox-
azinones with Benzoic Acid
Table 3. ortho-Benzoxylation Reaction of 2-o-Methyl phen-
ylbenzoxazinone with Aromatic Acids
a,b
a,b
O
N
O
N
O
N
O
O
O
O
O
O
O
O
O
OMe
3
qa, 71%
3qb, 70%
3
qc, 43%
O
O
O
O
N
O
N
O
N
O
O
O
O
N
O
O
O
O
O
O
Br
Ph
CF3
3
qd, 51%
3qe, 73%
3qf, 75%
3
qg, 73%
O
N
O
N
O
N
O
O
O
O
O
O
O
O
O
Me
Cl
Br
3
qh, 47%
3qi, 67%
3qj, 69%
O
O
O
O
N
O
N
O
N
a
Conditions: 1 (0.3 mmol), 2a (0.3 mmol), Pd(PPh
mmol), DCE (3 mL), under air, 120 °C, 12 h.
3
)
4
(5 mol %), CAN (0.36
O
O
O
Br
O
O
O
b
Isolated yield.
O2N
3
qk, 61%
3ql, 54%
3qm, 71%
Thereafter, versatility of the C-H benzoxylation with diversely
decorated benzoic acids was investigated (Table 3). In all cases,
benzoxylation occurs at the ortho-C-H bond to the benzoxazines
scaffold with excellent positional selectivity. As show, this
reaction with p-methoxybenzoic acid afforded product 3qc, and
the structure of 3qc was confirmed by X-ray crystallographic
analysis. This ortho-benzoxylation reaction was successfully
extended with various aromatic acids. A range of functional
groups, such as methyl, methoxy, halogen, trifluoromethyl and
nitro groups, were tolerated in this procedure. It seemed that the
benzoic acids with different substitutes on the benzene ring had a
slight effect on this transformation. Acids containing the
substitution at the 4-position with bromo, fluoro, methyl,
methoxy, phenyl, and trifluoromethyl groups underwent
oxygenation to give the esters 3qb-3qg in 43-75 %. Benzoic acid
with electron-donating and electron-withdrawing groups at the
para-position afforded minor differences results. In contrast,
product 3qd contains tert-butyl functional group in a relative low
yield (51 %). This was probably due to the steric hindrance. In
addition, benzoic acids bearing 2-methyl, 2-chloro, 2-bromo, 2-
nitro functional groups produced 3qh-3qk in moderate yields.
a
3 4
Conditions: 1q (0.3 mmol), 2 (0.3 mmol), Pd(PPh ) (5 mol %), CAN (0.36
mmol), DCE (3 mL), under air, 120 °C, 12 h.
b
Isolated yield.
Scheme 1. Plausible Reaction Mechanism of C-H
Benzoxylation

4
Tetrahedron
Cerium (IV) ammonium nitrate (CAN) was used in most
temperature , monitored by TLC. Next, the reaction mixture was
diluted with CH Cl and then filtered through Celite and silica
7
reactions as a one-electron oxidant. To gain some insight into
the mechanism of the reaction, a control experiment of 2-
phenylbenzoxazinone (1a) and benzoic acid (2a) under palladium
2
2
gel. The solvent was removed under reduced pressure and the
crude product was purified by column chromatography on a
silica gel using petroleum ether/ethyl acetate as the eluent.
(0) was performed in the presence of both CAN and radical
scavenger 2,2,6,6-tetramethylpiperidine-N-oxide (TEMPO) (2
equiv), the reaction was obviously suppressed, yielded a trace
amount of 3aa. In addition, the ESI-MS analysis of the reaction
mixture revealed the formation of the aroyl radical (see
Supporting Information) which suggesting a possible radical
involvement mechanism. Based on these observations and
4
(
.3.1. 2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl benzoate
3aa)
Yield 78 %; white solid; M.p: 127 – 129 C. H NMR (400
MHz, CDCl ) δ 8.33 (t, J = 8.7 Hz, 3H), 8.18 (d, J = 7.8 Hz, 1H),
.76 – 7.64 (m, 2H), 7.59 (t, J = 7.6 Hz, 3H), 7.47 (dt, J = 15.2,
7.6 Hz, 2H), 7.38 (d, J = 8.0 Hz, 1H), 6.78 (d, J = 8.1 Hz, 1H).
o
1
3
7
8
previous report, a plausible mechanism for this transformation is
13
3
C NMR (101 MHz, CDCl ) δ 165.6, 159.1, 154.2, 150.4, 146.4,
outlined in Scheme 1. Initially, palladium(0) complex is oxidized
by nitrate ions to generate a palladium(II) complex, then C-H
activation of two molecules 2-phenylbenzoxazinone (1a)
generates intermediate B. The benzoic acid (2a) was oxidized via
single electron transfer offered oxygen-centered radical C.
Second, the radical C reacted with the intermediate B to provide
the Pd (IV) intermediate D. Finally, the intermediate D
underwent reductive elimination to give the product 3aa, and
then enter the next catalytic cycle.
1
1
C
36.3, 133.6, 133.5, 130.9, 130.5, 129.9, 128.6, 128.5, 128.4,
27.0, 126.5, 124.7, 123.2, 117.0. HR-MS (ESI): m/z calcd for
+
21
H13NO
4
[M+H] 344.0917, found: 344.0931.
4.3.2. 2-(6-methoxy-4-oxo-4Hbenzo[d][1,3]oxazin-2-yl)phenyl
benzoate (3ba)
o
1
Yield 60 %; white solid; M.p: 187 – 188 C. H NMR (400
MHz, CDCl ) δ 8.31 (dd, J = 8.1, 1.2 Hz, 3H), 7.71 (t, J = 7.4 Hz,
3
1
H), 7.65 (td, J = 7.8, 1.6 Hz, 1H), 7.61 – 7.53 (m, 3H), 7.47 (td,
3
. CONCLUSION
J = 7.9, 1.0 Hz, 1H), 7.36 (dd, J = 8.0, 0.9 Hz, 1H), 7.15 (dd, J =
8
1
3
.9, 2.9 Hz, 1H), 6.70 (d, J = 8.9 Hz, 1H), 3.88 (s, 3H). C NMR
In conclusion, with benzoxazinone served as inherent
(101 MHz, CDCl ) δ165.6, 159.5, 159.4, 152.2, 150.2, 140.6,
3
directing group, with commercially available carboxylic acid, we
have developed here that Pd (0)/CAN catalysts system leading to
C-H ortho-benzoxylation. This protocol features moderate to
good yields, low catalyst loading, high tolerance of functional
groups, broad scope of both coupling partners, and excellent
ortho selectivity. The present study offers a valuable alternative
to the known C-H oxygenation reactions, and expands the field
of benzoxazinone as directing groups and the scope of Pd (0)-
catalyzed C-H activation chemistry.
1
1
33.5, 133.1, 130.6, 130.5, 130.0, 128.6, 128.5, 126.4, 125.7,
24.6, 123.2, 117.8, 108.5, 55.9. HR-MS (ESI): m/z calcd for
+
C H NO [M+H] 374.1023, found: 374.1037.
22
15
5
4
.3.3.
2-(6-methyl-4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
benzoate (3ca)
o
1
Yield: 63 %; white solid; M.p: 133 – 134 C. H NMR (400
MHz, CDCl ) δ 8.31 (dt, J = 8.5, 1.7 Hz, 3H), 7.96 (s, 1H), 7.74 –
3
7
.63 (m, 2H), 7.58 (t, J = 7.7 Hz, 2H), 7.51 – 7.44 (m, 1H), 7.38
4
. EXPERIMENTAL SECTION
(ddd, J = 8.8, 8.2, 1.2 Hz, 2H), 6.67 (d, J = 8.2 Hz, 1H), 2.42 (s,
13
3
1
H). C NMR (101 MHz, CDCl
3
) δ 165.6, 159.3, 153.4, 150.3,
4
.1. General information
44.3, 139.0, 137.6, 133.5, 133.2, 130.7, 130.5, 130.0, 128. 6,
Chemicals and reagents were purchased from commercial
128.0, 126.8, 126.4, 124.6, 123.2, 116.7, 21.3. HR-MS (ESI):
m/z calcd for C H NO [M+H] 358.1074, found: 358.1091.
1
13
+
suppliers and used without special instructions. H NMR and
NMR spectra were obtained on a Bruker 400 MHz instrument in
CDCl using TMS as internal standard, operating at 400 MHz
and 101 MHz, respectively. Chemical shifts (δ) are expressed in
ppm and coupling constants J are given in Hz. Abbreviations are
as follows: s (singlet), d (doublet), t (triplet), m (multiplet). High
resolution mass spectra (HRMS) were obtained on Agilent 6520
LC/MS with ESI source. Unless otherwise noted, the purification
was performed using column chromatography on silica gel.
C
22
15
4
4
.3.4.
benzoate (3da)
Yield: 72 %; white solid; M.p: 169 – 171 C. H NMR (400
MHz, CDCl ) δ 8.31 (ddd, J = 8.4, 5.1, 1.5 Hz, 3H), 7.81 (dd, J =
2-(6-fluoro-4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
3
o
1
3
7
7
.8, 2.9 Hz, 1H), 7.70 (ddd, J = 11.5, 9.6, 4.5 Hz, 2H), 7.59 (t, J =
.8 Hz, 2H), 7.49 (td, J = 7.9, 1.1 Hz, 1H), 7.37 (dd, J = 8.1, 1.0
1
3
Hz, 1H), 7.34 – 7.29 (m, 1H), 6.75 (dd, J = 8.9, 4.8 Hz, 1H).
NMR (101 MHz, CDCl ) δ 165.5, 162.7, 160.2, 158.3 (d, J
3
1
Hz), 128.6, 126.5, 124.7, 124.6, 124.4, 122.8, 118.3 (d, J C-F = 8.9
Hz), 113.9, 113.6. HR-MS (ESI): m/z calcd for C H FNO
C
=
4
.2. General procedure for the synthesis of 2-arylbenzoxazinones
9
3
C-F
(1)
.4 Hz), 153.5 (d, J C-F = 2.5 Hz), 150.4, 143.0 (d, J C-F = 2.5 Hz),
33.6 (d, J C-F = 6.0 Hz), 130.8, 130.5, 129.7, 129.3 (d, J C-F = 8.2
To a mixture of concentrated anthranilic acid (10 mmol),
Na CO (20 mmol) in THF (20 mL), benzoyl chloride was added
2
3
2
1
12
4
drop wise at 0°C. After 10 min, the cold-bath was removed, and
the mixture was stirred at room temperature overnight. After the
reaction was complete, water (20 mL) was added, and the
mixture was stirred for 10 min prior to filtration. After removal
of the solvent, the solid was washed with water and 50% aqueous
MeOH respectively to get the desired product 1 (1a-1p).
+
[
M+H] 362.0823, found: 362.0831.
4
.3.5.
2-(6-chloro-4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
benzoate (3ea)
Yield: 75 %; white solid; M.p: 157 – 159 C. H NMR (400
MHz, CDCl ) δ 8.37 – 8.24 (m, 3H), 8.12 (d, J = 2.4 Hz, 1H),
.70 (ddd, J = 10.8, 9.4, 4.5 Hz, 2H), 7.58 (t, J = 7.7 Hz, 2H),
.54 - 7.45 (m, 2H), 7.37 (dd, J = 8.1, 0.8 Hz, 1H), 6.67 (d, J =
o
1
3
4
.3. General procedure for the Direct Ortho-Benzoxylation of 2-
7
7
Phenylbenzoxazinone with carboxylic acid
13
2
-phenylbenzoxazinone 1 (0.3 mmol), benzoic acid 2 (0.3
3
8.6 Hz, 1H). C NMR (101 MHz, CDCl ) δ 165.5, 158.0, 154.3,
mmol), Pd(PPh ) (5 mol %), CAN (0.36 mmol, 1.2 equive),
150.5, 144.9, 136.7, 134.2, 133.7, 133.7, 130.8, 130.5, 129.8,
3
4
DCE (3 mL) were added to a test tube, the mixture was stirred at
20 °C under air for 12 h., After being cooled to ambient
128.6, 128.4, 127.7, 126.5, 124.7, 122.7, 118.1. HR-MS (ESI):
+
1
m/z calcd for C21
H12ClNO
4
[M+H] 378.0528, found: 378.0539.

5
4
.3.6.
benzoate (3fa)
Yield: 76 %; white solid; M.p: 159 – 160 C. H NMR (400
MHz, CDCl ) δ 8.38 – 8.25 (m, 4H), 7.75 – 7.64 (m, 3H), 7.58 (t,
J = 7.7 Hz, 2H), 7.52 – 7.45 (m, 1H), 7.37 (d, J = 8.1 Hz, 1H),
2-(6-bromo-4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
J = 7.4 Hz, 1H), 7.58 (dt, J = 2.8, 2.0 Hz, 3H), 7.51 – 7.38 (m,
H), 7.25 (d, J = 8.2 Hz, 1H), 6.82 – 6.72 (m, 1H), 2.50 (s, 3H).
2
13
3
C NMR (101 MHz, CDCl ) δ 165.8, 159.2, 154.3, 148.2, 146.5,
136.4, 136.3, 134.1, 133.5, 131.1, 130.5, 130.0, 128.6, 128.4,
128.4, 127.0, 124.4, 122.5, 117.0, 20.9. HR-MS (ESI): m/z calcd
o
1
3
+
for C H NO [M+H] 358.1074, found: 358.1079.
2
2
15
4
13
6
1
1
3
.60 (d, J = 8.6 Hz, 1H). C NMR (101 MHz, CDCl ) δ 165.5,
57.8, 154.5, 150.5, 145.3, 139.5, 133.8, 133.7, 130.9, 130.5,
4
.3.12. 5-methoxy-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
benzoate (3la)
Yield: 62 %; white solid; M.p: 198 – 199 C. H NMR (400
MHz, CDCl ) δ 8.31 (dd, J = 10.4, 8.9 Hz, 3H), 8.15 (d, J = 7.8
Hz, 1H), 7.73 (t, J = 7.4 Hz, 1H), 7.64 – 7.49 (m, 3H), 7.40 (t, J =
29.8, 128.6, 128.6, 126.5, 124.7, 122.8, 121.8, 118.3. HR-MS
+
(ESI): m/z calcd for C21
H
12BrNO
4
[M+H] 422.0022, found:
o
1
4
22.0015.
3
4
.3.7. 3-methoxy-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
7
1
.6 Hz, 1H), 6.99 (dd, J = 8.9, 2.5 Hz, 1H), 6.89 (d, J = 2.5 Hz,
H), 6.64 (d, J = 8.1 Hz, 1H), 3.94 (s, 3H). C NMR (101 MHz,
benzoate (3ga)
13
o
1
Yield: 63 %; white solid; M.p: 159 – 160 C. H NMR (400
CDCl
3
) δ 165.5, 163.7, 159.3, 154.1, 152.2, 146.8, 136.2, 133.6,
MHz, CDCl ) δ 8.21 (dd, J = 7.9, 1.1 Hz, 1H), 8.11 – 8.02 (m,
132.1, 130.6, 130.0, 128.6, 128.3, 127.9, 126.6, 116.8, 115.3,
3
2
H), 7.71 (td, J = 8.1, 1.4 Hz, 1H), 7.59 – 7.48 (m, 3H), 7.39 (dd,
112.3, 110.3, 55.8. HR-MS (ESI): m/z calcd for C22
[M+H] 374.1023, found: 374.1025.
H
15NO
5
+
J = 10.7, 4.7 Hz, 3H), 7.07 – 7.02 (m, 1H), 6.97 (d, J = 8.4 Hz,
1
MHz, CDCl ) δ 164.6, 159.7, 159.1, 154.1, 150.3, 146.4, 136.3,
1
1
13
13
H), 3.92 (s, 3H). C NMR (101 MHz, CDCl3) C NMR (101
4
.3.13. 5-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
benzoate (3ma)
Yield: 71 %; white solid; M.p: 192 – 193 C. H NMR (400
MHz, CDCl ) δ 8.36 – 8.28 (m, 2H), 8.23 (d, J = 8.1 Hz, 1H),
8.16 (dd, J = 7.8, 1.1 Hz, 1H), 7.72 (t, J = 7.4 Hz, 1H), 7.57 (dt, J
9.6, 4.7 Hz, 3H), 7.42 (dd, J = 11.2, 4.0 Hz, 1H), 7.27 (s, 1H),
3
33.6, 132.2, 130.2, 129.1, 128.7, 128.5, 128.4, 127.0, 117.1,
15.5, 115.2, 109.1, 56.4, HR-MS (ESI): m/z calcd for
o
1
+
C H NO [M+H] 374.1023, found: 374.1045.
22
15
5
3
4
.3.8.
3-fluoro-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
=
benzoate (3ha)
13
7
.18 (s, 1H), 6.72 (d, J = 8.0 Hz, 1H), 2.50 (s, 3H). C NMR
o
1
Yield: 42 %; white solid; M.p: 126 – 128 C. H NMR (400
(101 MHz, CDCl ) δ 165.7, 159.2, 154.2, 150.4, 146.6, 144.8,
3
MHz, CDCl ) δ 8.21 (d, J = 7.8 Hz, 1H), 8.15 (d, J = 7.8 Hz, 2H),
136.2, 133.5, 130.7, 130.5, 130.1, 128.6, 128.3, 128.2, 127.3,
126.8, 125.2, 120.1, 117.0, 21.5. HR-MS (ESI): m/z calcd for
3
7
7
.70 (t, J = 7.7 Hz, 1H), 7.66 – 7.58 (m, 2H), 7.50 (dt, J = 19.5,
.7 Hz, 3H), 7.23 (dd, J = 19.8, 8.6 Hz, 3H). C NMR (101
13
C
22
H
15NO
4
[M+H]+ 358.1074, found: 358.1094.
5-fluoro-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
benzoate (3na)
MHz, CDCl ) δ 164.8, 162.6, 160.1, 158.9, 151.9, 150.4 (d, J
3
C-F
4
.3.14.
=
1
,
4.4 Hz), 146.0, 136.4, 133.8, 132.7 (d, J C-F = 10.3 Hz), 130.3,
29.1, 128.9, 128.6, 128.5, 127.1, 119.7 (d, J C-F = 3.6 Hz), 117.1
114.5 (d, J C-F =15.2Hz), 114.2 (d, J C-F =22.2Hz), 114.1. HR-MS
o
1
+
Yield: 46 %; white solid; M.p: 169 – 171 C. H NMR (400
(ESI): m/z calcd for C H FNO [M+H] 362.0823, found:
21 12 4
MHz, CDCl ) δ 8.40 – 8.27 (m, 3H), 8.17 (dd, J = 7.8, 1.2 Hz,
3
3
62.0833.
.3.9. 3-chloro-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
1
H), 7.74 (t, J = 7.5 Hz, 1H), 7.58 (ddd, J = 8.0, 6.5, 2.6 Hz, 3H),
4
7.49 – 7.41 (m, 1H), 7.20 (ddd, J = 8.9, 7.7, 2.6 Hz, 1H), 7.13
13
(
dd, J = 8.7, 2.5 Hz, 1H), 6.73 (d, J = 8.0 Hz, 1H). C NMR (101
benzoate (3ia)
Yield: 43 %; white solid; M.p: 119 – 121 C. H NMR (400
MHz, CDCl ) δ 8.23 (d, J = 7.8 Hz, 1H), 8.05 (d, J = 7.6 Hz, 2H),
.77 (t, J = 7.7 Hz, 1H), 7.57 (dd, J = 14.9, 7.1 Hz, 3H), 7.49 (dd,
MHz, CDCl ) δ 166.4, 165.1, 163.8, 158.9, 153.4, 152.0 (d, J
3
C-F
o
1
= 11.5 Hz), 146.4, 136.4, 133.8, 132.5 (d, J C-F = 10.1 Hz), 130.6,
129.5, 128.7, 128.5 (d, J C-F = 11.1 Hz), 126.9, 119.6 (d, J C-F
3
=
7
3.7 Hz), 116.9, 113.9, 113.7, 112.9, 112.7. HR-MS (ESI): m/z
13
+
J = 7.9, 5.1 Hz, 2H), 7.41 (t, J = 7.6 Hz, 3H). C NMR (101
MHz, CDCl ) δ 164.3, 159.0, 153.5, 150.3, 145.9, 136.6, 134.3,
33.9, 131.9, 130.2, 129.2, 128.6, 128.5, 127.6, 127.3, 125.2,
calcd for C H FNO [M+H] 362.0823, found: 362.0831.
21
12
4
3
4
.3.15. 5-chlore-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
1
1
3
22.0, 117.0. HR-MS (ESI): m/z calcd for C21
78.0528, found: 378.0543.
4
H12ClNO [M+H]+
benzoate (3oa)
o
1
Yield: 48 %; white solid; M.p: 192 – 194 C. H NMR (400
4
.3.10. 3-bromo-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
MHz, CDCl ) δ 8.29 (dd, J = 7.8, 6.1 Hz, 3H), 8.17 (dd, J = 7.8,
3
1
7
.0 Hz, 1H), 7.74 (t, J = 7.5 Hz, 1H), 7.59 (t, J = 7.8 Hz, 3H),
.45 (ddd, J = 21.2, 8.4, 2.0 Hz, 3H), 6.74 (d, J = 8.0 Hz, 1H). C
benzoate (3ja)
Yield: 38 %; white solid; M.p: 119 – 121 C. H NMR (400
MHz, CDCl ) δ 8.23 (dd, J = 7.9, 1.3 Hz, 1H), 8.03 (dd, J = 8.2,
.1 Hz, 2H), 7.78 (td, J = 8.0, 1.5 Hz, 1H), 7.65 (dd, J = 7.6, 1.5
13
o
1
NMR (101 MHz, CDCl ) δ 165.2, 158.8, 153.4, 151.0, 146.3,
139.1, 136.4, 133.8, 131.6, 130.6, 129.5, 128.7, 128.5, 126.9,
126.7, 125.3, 121.7, 117.0, 29.7. HR-MS (ESI): m/z calcd for
3
3
1
13
+
Hz, 1H), 7.48 (dddd, J = 25.1, 23.7, 11.6, 4.4 Hz, 7H). C NMR
101 MHz, CDCl ) δ 164.2, 159.0, 154.3, 150.3, 145.9, 136.6,
33.9, 132.2, 130.6, 130.2, 129.3, 128.6, 128.5, 128.4, 127.3,
27.2, 122.6, 122.5, 117.0. HR-MS (ESI): m/z calcd for
C H ClNO [M+H] 378.0528, found: 378.0538.
21
12
4
(
3
4
.3.16. 5-bromo-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
1
1
benzoate (
3
pa
)
+
C
21
H
12BrNO
4
[M+H] 422.0022, found: 422.0040.
.3.11. 4-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
benzoate (3ka)
Yield: 55 %; white solid; M.p: 193 – 195 C. H NMR (400
o
1
Yield: 61 %; white solid; M.p: 173 – 175 C. H NMR (400
4
MHz, CDCl ) δ 8.32 – 8.27 (m, 2H), 8.22 – 8.14 (m, 2H), 7.73 (t,
J = 7.5 Hz, 1H), 7.65 – 7.55 (m, 5H), 7.48 – 7.43 (m, 1H), 6.74
3
13
(d, J = 8.1 Hz, 1H). C NMR (101 MHz, CDCl ) δ 165.2, 158.8,
3
o
1
153.5, 150.8, 146.3, 136.4, 133.8, 131.7, 130.6, 129.8, 129.5,
128.7, 128.6, 128.5, 128.2, 127.2, 127.0, 122.2, 117.0. HR-MS
MHz, CDCl ) δ 8.36 – 8.25 (m, 2H), 8.21 – 8.10 (m, 2H), 7.71 (t,
3

6
Tetrahedron
+
o
1
(
ESI): m/z calcd for C H BrNO [M+H] 422.0022, found:
Yield: 75 %; white solid; M.p: 152 – 154 C. H NMR (400
MHz, CDCl ) δ 8.21 (dd, J = 7.9, 1.2 Hz, 1H), 8.16 (d, J = 8.4
Hz, 2H), 7.77 – 7.70 (m, 1H), 7.66 – 7.60 (m, 4H), 7.55 – 7.39
21
12
4
4
22.0018.
3
4
.3.17. 3-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
13
(
m, 6H), 7.28 (d, J = 4.6 Hz, 2H), 2.57 (s, 3H). C NMR (101
MHz, CDCl ) δ 164.8, 159.3, 155.7, 149.7, 146.3, 146.2, 139.8,
39.4, 136.5, 131.4, 130.7, 129.0, 128.9, 128.5, 128.4, 128.3,
27.9, 127.3, 127.2, 127.1, 124.9, 120.9, 116.8, 20.3. HR-MS
benzoate (3qa)
3
1
1
o
1
Yield: 71 %; white solid; M.p: 104 – 106 C. H NMR (400
MHz, CDCl ) δ 8.20 (dd, J = 7.9, 1.2 Hz, 1H), 8.12 – 8.06 (m,
+
3
4
(ESI): m/z calcd for C28H19NO [M+H] 434.1387, found:
2
1
2
1
1
H), 7.73 (td, J = 8.1, 1.5 Hz, 1H), 7.56 (dd, J = 12.7, 5.3 Hz,
H), 7.54 – 7.47 (m, 2H), 7.45 – 7.38 (m, 3H), 7.28 – 7.24 (m,
H), 2.56 (s, 3H). C NMR (101 MHz, CDCl ) δ 164.9, 159.3,
55.7, 149.7, 146.2, 139.4, 136.5, 133.6, 131.4, 130.2, 129.2,
4
34.1389.
13
4.3.23. 3-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
-(trifluoromethyl) Benzoate (3qg)
Yield: 73 %; white solid; M.p:134-136 C. H NMR (400
MHz, CDCl ) δ 8.21 (d, J = 8.0 Hz, 3H), 7.78 – 7.66 (m, 3H),
.53 (dd, J = 16.2, 8.0 Hz, 2H), 7.38 (d, J = 8.1 Hz, 1H), 7.30 (d,
3
4
28.9, 128.5, 128.5, 128.4, 127.1, 124.9, 120.9, 116.8, 20.3. HR-
+
o
1
MS (ESI): m/z calcd for C H NO [M+H] 358.1074, found:
22
15
4
3
4
4
58.1073.
3
7
.3.18. 3-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
13
J = 7.9 Hz, 1H), 7.26 (d, J = 8.2 Hz, 1H), 2.57 (s, 3H). C NMR
(101 MHz, CDCl ) δ 163.8, 159.1, 155.5, 149.3, 146.1, 139.7
36.6, 135.2, 134.8, 132.4, 131.5, 130.5, 129.0, 128.8, 128.5,
-methylbenzoate (3qb)
3
1
1
1
o
1
Yield: 70 %; white solid; M.p: 110 – 111 C. H NMR (400
MHz, CDCl ) δ 8.21 (d, J = 7.8 Hz, 1H), 7.97 (d, J = 8.1 Hz,
27.0, 125.6 (q, J C-F = 3.6 Hz), 124.7 (d, J C-F = 19.4 Hz), 122.1,
20.8, 116.7, 29.3, 20.4. HR-MS (ESI): m/z calcd for
3
2
H), 7.75 (t, J = 7.7 Hz, 1H), 7.56 – 7.42 (m, 3H), 7.28 – 7.16
+
C
23
H
14
F
3
NO
4
[M+H] 426.0948, found: 426.0952.
13
(m, 4H), 2.55 (s, 3H), 2.40 (s, 3H). C NMR (101 MHz, CDCl )
3
δ 164.9 , 159.3, 155.7, 149.7, 146.2, 144.4, 139.3, 136.4, 131.3,
4.3.24. 3-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
-methylbenzoate (3qh)
Yield: 47 %; white solid; M.p: 120 – 121 C. H NMR (400
MHz, CDCl ) δ 8.21 (dd, J = 7.9, 1.2 Hz, 1H), 8.01 (d, J = 6.9
1
1
30.2, 129.2, 128.8, 128.5, 128.3, 127.2, 126.4, 124.9, 120.9,
16.8, 21.7, 20.3. HR-MS (ESI): m/z calcd for C H NO
2
23
17
4
+
o
1
[
M+H] 372.1230, found: 372.1220.
3
4
4
.3.19. 3-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
Hz, 1H), 7.77 (td, J = 8.1, 1.5 Hz, 1H), 7.58 – 7.47 (m, 3H), 7.44
– 7.37 (m, 1H), 7.28 – 7.14 (m, 4H), 2.62 (s, 3H), 2.55 (s, 3H).
-methoxybenzoa-te (3qc)
13
o
1
3
C NMR (101 MHz, CDCl ) δ 165.4, 159.3, 155.9, 149.6, 146.2,
Yield: 43 %; white solid; M.p: 170 – 172 C. H NMR (400
MHz, CDCl ) δ 8.21 (dd, J = 7.9, 1.2 Hz, 1H), 8.04 (d, J = 8.9
Hz, 2H), 7.79 – 7.71 (m, 1H), 7.50 (dt, J = 15.2, 7.3 Hz, 3H),
1
1
41.5, 139.3, 136.5, 132.7, 131.8, 131.4, 131.1, 128.9, 128.5,
3
28.3, 128.0, 127.1, 125.8, 125.1, 121.0, 116.9, 21.7, 20.3. HR-
+
MS (ESI): m/z calcd for C23
372.1243.
H17NO
4
[M+H] 372.1230, found:
7
3
1
1
.25 (dd, J = 7.9, 3.9 Hz, 2H), 6.88 (d, J = 8.9 Hz, 2H), 3.86 (s,
H), 2.54 (s, 3H). C NMR (101 MHz, CDCl ) δ 164.5, 163.9,
3
59.3, 155.8, 149.7, 146.2, 139.3, 136.5, 132.3, 131.3, 128.8,
13
4.3.25. 3-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
28.5, 128.2, 127.2, 124.9, 121.4, 121.0, 116.8, 113.8, 55.5, 20.3.
+
2-chlorobenzoate (3qi)
HR-MS (ESI): m/z calcd for C23
found: 388.1193.
H17NO
5
[M+H] 388.1179,
o
1
Yield: 67 %; white solid; M.p: 120 – 122 C. H NMR (400
MHz, CDCl ) δ 8.23 (dd, J = 8.2, 1.4 Hz, 1H), 7.95 (d, J = 7.5
3
4
.3.20. 3-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl4-
tert-butyl)benzo-ate (3qd)
Yield: 51 %; white solid; M.p: 134 – 135 C. H NMR (400
MHz, CDCl ) δ 8.21 (dd, J = 7.9, 1.1 Hz, 1H), 8.01 (d, J = 8.5
Hz, 2H), 7.77 – 7.69 (m, 1H), 7.51 (dt, J = 13.9, 7.9 Hz, 2H),
Hz, 1H), 7.79 (td, J = 7.9, 1.5 Hz, 1H), 7.59 – 7.47 (m, 3H), 7.43
1
3
(
(dd, J = 4.8, 1.6 Hz, 2H), 7.29 – 7.24 (m, 3H), 2.55 (s, 3H).
C
o
1
NMR (101 MHz, CDCl ) δ 163.7, 159.3, 155.6, 149.2, 146.2,
3
1
1
39.5, 136.6, 134.3, 133.2, 132.1, 131.4, 131.2, 129.0, 128.7,
3
28.7, 128.5, 127.2, 126.7, 124.9, 120.8, 117.0, 20.3. HR-MS
+
(ESI): m/z calcd for C H ClNO [M+H] 392.0684, found:
22
14
4
7
9
1
1
.45 – 7.38 (m, 3H), 7.28 – 7.22 (m, 2H), 2.54 (s, 3H), 1.33 (s,
13
392.0673.
3
H). C NMR (101 MHz, CDCl ) δ 164.9, 159.3, 157.4, 155.7,
49.7, 146.2, 139.3, 136.4, 131.3, 130.1, 128.8, 128.4, 128.2,
4.3.26. 3-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
27.2, 126.4, 125.5, 124.9, 121.0, 116.9, 35.1, 34.1, 20.2. HR-
+
2-bromobenzoate (3qj)
MS (ESI): m/z calcd for C26
4
H23NO
4
[M+H] 414.1700, found:
o
1
14.1701.
Yield: 69 %; white solid; M.p: 107 – 108 C. H NMR (400
MHz, CDCl ) δ 8.24 (dd, J = 7.8, 0.7 Hz, 1H), 7.93 (dd, J = 6.4,
.0 Hz, 1H), 7.84 – 7.75 (m, 1H), 7.68 – 7.48 (m, 4H), 7.37 –
3
4
4
.3.21. 3-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
3
1
3
-bromobenzoate (3qe)
7.30 (m, 2H), 7.28 (d, J = 7.8 Hz, 2H), 2.55 (s, 3H). C NMR
(101 MHz, CDCl ) δ 164.1, 159.3, 155.6, 149.2, 146.2, 139.5,
36.5, 134.6, 133.2, 132.0, 131.4, 130.7, 129.0, 128.7, 128.5
127.2, 127.2, 124.9, 122.3, 120.8, 117.0, 20.3. HR-MS (ESI):
o
1
3
Yield: 73 %; white solid; M.p: 177 – 178 C. H NMR (400
MHz, CDCl ) δ 8.21 (d, J = 7.8 Hz, 1H), 7.95 (dd, J = 8.6, 2.2
Hz, 2H), 7.77 (t, J = 7.6 Hz, 1H), 7.62 – 7.47 (m, 4H), 7.42 (d, J
1
3
,
+
13
m/z calcd for C22
4.3.27. 3-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
-nitrobenzoate (3qk)
Yield: 61 %; white solid; M.p: 120 – 122 C. H NMR (400
4
H14BrNO [M+H] 436.0179, found: 436.0191.
=
8.0 Hz, 1H), 7.28 – 7.21 (m, 2H), 2.56 (d, J = 1.9 Hz, 3H). C
3
NMR (101 MHz, CDCl ) δ 164.2, 159.2, 155.6, 149.4, 146.1,
1
1
39.5, 136.6, 131.9, 131.6, 131.4, 129.0, 128.9, 128.6, 128.5,
28.1, 127.1, 124.7, 120.8, 116.8, 20.4. HR-MS (ESI): m/z calcd
2
+
o
1
for C22
H
14BrNO
4
[M+H] 436.0179, found: 436.0186.
.3.22. 3-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl[1
1’-biphenyl]-4-carboxylate (3qf)
MHz, CDCl ) δ 8.27 (d, J = 7.8 Hz, 1H), 8.00 (d, J = 7.7 Hz, 1H),
3
4
7
.86 (t, J = 7.2 Hz, 2H), 7.72 – 7.51 (m, 5H), 7.39 (d, J = 8.1 Hz,
13
,
1H), 7.31 (s, 1H), 2.55 (s, 3H). C NMR (101 MHz, CDCl ) δ
3

7
L. Zhang, G. F. Pan, X. Q. Zhu, R. L. Guo, Y. R. Gao, and Y. Q.
Wang. Org. Lett. 2019, 21, 2731-2735.
1
1
1
64.0, 159.3, 155.5, 148.9, 146.2, 139.6, 136.6, 133.4, 131.9,
31.6, 130.1, 129.1, 129.0, 128.6, 127.3, 127.2, 124.7, 124.1,
20.5, 117.1, 20.3. HR-MS (ESI): m/z calcd for C H N O
3
.
For selected reports on direct acetoxylation of C-H bonds, see: (a)
A. R. Dick, K. L. Hull and M. S. Sanford, J. Am. Chem. Soc.
004, 126, 2300-2301. (b) D. Kalyani and M. S. Sanford. Org.
22
14
2
6
+
[
M+H] 403.0925, found: 403.0921.
2
Lett. 2005, 7, 4149-4152. (c) Z. Wang, Y. Kuninobu, M. Kanai,
Org. Lett. 2014, 16, 4790-4793. (d) R. K. Rit, M. R. Yadav and A.
K. Sahoo, Org. Lett. 2014, 16, 968-971. (e) H. Zhang, R. B. Hu,
X. Y. Zhang, S. X. Li, S. D. Yang, Chem. Commun. 2014, 50,
4
3
.3.28. 3-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
-methylbenzoate (3ql)
o
1
4
686-4689. (f) G. Yang, P. Lindovska, D. Zhu, J. Kim, P. Wang,
R. Y. Tang, M. Movassaghi, J. Q. Yu. J. Am. Chem. Soc. 2014,
36, 10807-10813. (g) C. K. Hazra, Q. Dherbassy, J. Wencel-
Delord and F. Colobert, Angew. Chem., Int. Ed. 2014, 53, 13871-
3875. (h) T. Cheng, W. Yin, Y. Zhang, Y. Zhang and Y. Huang,
Yield: 54 %; white solid; M.p: 103 – 104 C. H NMR (400
MHz, CDCl ) δ 8.19 (dd, J = 7.9, 1.0 Hz, 1H), 7.89 (d, J = 6.1
Hz, 2H), 7.73 (dd, J = 15.4, 1.4 Hz, 1H), 7.53 – 7.44 (m, 3H),
7
1
CDCl ) δ 164.9, 159.3, 155.8, 149.7, 146.2, 139.3, 138.4, 136.5,
1
1
3
1
.35 (d, J = 7.6 Hz, 1H), 7.29 (d, J = 3.6 Hz, 1H), 7.26 (dd, J =
1
13
1.9, 5.8 Hz, 2H), 2.54 (s, 3H), 2.31 (s, 3H). C NMR (101 MHz,
Org. Biomol. Chem. 2014, 12, 1405–1411. (i) Q. Li, S.-Y. Zhang,
G. He, W. A. Nack and G. Chen, Adv. Synth. Catal. 2014, 356,
3
1
544-1548. (j) M. Wang, Y. Yang, Z. Fan, Z. Cheng, W. Zhu and
34.4, 131.3, 130.7, 129.1, 128.9, 128.5, 128.4, 128.3, 127.3,
A. Zhang, Chem. Commun. 2015, 51, 3219–3222; (k) K. Chen, S.
Q. Zhang, H. Z. Jiang, J. W. Xu and B. F. Shi, Chem. Eur. J.
2015, 21, 3264-3270. (l) B. Wang, C. Lin, Y. Liu, Z. Fan, Z. Liu
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27.2, 124.9, 120.9, 116.8, 21.1, 20.3. HR-MS (ESI): m/z calcd
+
for C H NO [M+H] 372.1230, found: 372.1242.
23
17
4
4
3
.3.29. 3-methyl-2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl
-bromobenzoate (3qm)
6
958-6964. (o) D. Sarkar, A. V. Gulevich, F. S. Melkonyan and V.
o
1
Yield: 71 %; white solid; M.p: 140 – 141 C. H NMR (400
MHz, CDCl ) δ 8.25 – 8.18 (m, 2H), 8.01 (d, J = 7.8 Hz, 1H),
7
1
Gevorgyan, ACS Catal. 2015, 5, 6792-6801. (p) A. Maji, B.
Bhaskararao, S. Singha, R. B. Sunoj and D. Maiti, Chem. Sci.
3
2
016, 7, 3147-3153. (q) N. V. Rajkumar, S. A. Babu and B.
.79 – 7.66 (m, 2H), 7.56 – 7.43 (m, 3H), 7.30 (d, J = 8.1 Hz,
Gopalakrishnan. J. Org. Chem. 2016, 81, 12197-12211. (r) Z.-L.
Zang, S. Zhao, S. Karnakanti, C.-L. Liu, P.-L. Shao and Y. He.
Org. Lett. 2016, 18, 5014-5017.
13
H), 7.26 (d, J = 8.6 Hz, 2H), 2.56 (s, 3H).. C NMR (101 MHz,
CDCl ) δ 163.6, 159.1, 155.5, 149.4, 146.1, 139.5, 136.6, 136.5,
3
1
1
33.1, 131.4, 131.2, 130.1, 129.0, 128.7, 128.7, 128.5, 127.1,
4. For the direct benzoxylation of C-H bonds, see: (a) Z. S. Ye, W.
H. Wang and F. Luo, S.H. Zhang, J. Cheng, Org. Lett. 2009, 11,
3974-3977. (b) F. Luo, C. Pan, J. Cheng, Synlett 2012, 23, 357-
24.7, 122.6, 120.7, 116.8, 20.4. HR-MS (ESI): m/z calcd for
+
C H BrNO [M+H] 436.0179, found: 436.0194.
22
14
4
3
66. (c) E. B. Shi, Y. Shao, S. L. Chen, H. Y. Hu, Z. J. Liu, J.
Zhang, X. B. Wan, Org. Lett. 2012, 14, 3384-3387. (d) C. J. Hu,
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Declaration of competing interest
2
4
468. (e) K. Padala and M. Jeganmohan, Chem. Commun. 2013,
9, 9651-9653. (f) W. N. Sit, C. W. Chan and W. Y. Yu,
The authors declare no competing financial interest.
Molecules 2013, 18, 4403-4418. (g) J. Zhao, H. Fang, W. Zhou, J.
Han, Y. Pan, J. Org. Chem. 2014, 79, 3847-3855. (h) S. K. Rout,
S. Guin, A. Gogoi, G. Majji, and B. K. Patel, Org. Lett. 2014, 16,
Acknowledgments
We are grateful for support from National Key R&D Program
of China (2018YFF0212503) and China Scholarship Council
1
2
614−1617. (i) K. Padala and M. Jeganmohan, Chem. Eur. J.
014, 20, 4092-4097. (j) Q. Zhang, Y. Wang, T. T. Yang, L. Li, D.
(
No. 201706465059).
Appendix A. Supplementary data
Supporting Information
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Highlights for this article (TET 130969) are as follows:
2
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The direct oxygenation of C(sp )-H bonds of benzoxazinones with carboxylic acid was
achieved.
>
>
>
Benzoxazinone was served as inherent directing group.
The reaction gave the desired product with excellent ortho selectivity.
The reaction does not require any ligands or additives.

Declaration of Interest Statement
The authors declare no competing financial interest. We declare that we do not
have any commercial or associative interest that represents a conflict of interest in
connection with the work submitted.