RhIII-Catalyzed Regioselective Preparation of 3-Hetero-Substituted Isocoumarins from Aryl Carboxylic Acids and Alkynes

Article abstract of DOI:10.1002/ejoc.201601330

An oxygen-mediated annulation reaction has been reported herein. Various 3-hetero-substituted isocoumarins were successfully prepared with high efficiency (yields up to 88 %) and good functional-group tolerance (35 examples) in the presence of a rhodium catalyst. A plausible mechanism has also been proposed that shows the high regioselectivity mostly likely originates from the electron-density difference between the alkynyl carbon atoms of the substrate.

Full text of DOI:10.1002/ejoc.201601330

A Journal of
Accepted Article
Title: Rh(III)-Catalyzed Regioselective Preparation of 3-Hetero Isocoumarins from
Aryl Carboxylic Acid and Alkynes
Authors: Wanrong Dong; Lijuan Song; Jing Xiao; Delie An; Zhihong Peng
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To be cited as: Eur. J. Org. Chem. 10.1002/ejoc.201601330
Link to VoR: http://dx.doi.org/10.1002/ejoc.201601330
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European Journal of Organic Chemistry
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Rh(III)-Catalyzed Regioselective Preparation of 3-Hetero
Isocoumarins from Aryl Carboxylic Acids and Alkynes
Lijuan Song, Jing Xiao, Wanrong Dong*, Zhihong Peng* and Delie An*
Abstract: An oxygen-mediated annulation reaction was herein
demonstrated. Various unreported 3-hetero substituted isocoumarins
were successfully prepared with high efficiency (up to 88% yields)
and good functional groups tolerance (35 examples) in the presence
of a rhodium catalyst. Moreover, a plausible mechanism was
proposed that the high regio-selectivity probably originated from the
difference of the electron-density on the alkynyl carbons.
knowledge that alkynyl phosphonates have been successfully
applied for the construction of some hetero- or carbo- cyclic
compounds,[23] there are still rare literal demonstrations on the
synthesis of P or N substituted isocoumarins from alkynyl
phosphonates through the direct C-H bond activation pathway
using oxygen as a clean oxidant. Within this context, we wish to
report an annulation reaction towards the novel products under
O2 atmosphere based on the successful formation of hetero-
alkynyl bonds from our group.[24]
Introduction
Different pharmacophores bearing isocoumarin structural
subunit have aroused extensive research interests due to the
exhibition of a broad range of clinical and biological properties
such
as
antifungal,[1]
antiulcer,[2]
anti-inflamatory,[3]
antibacterial,[4] herbicidal,[5] cytotoxic,[6] and antiangiogenic
activities,[7] etc., as well for being significant synthetic
intermediates towards some heterocyclic or carbocyclic
compounds
like
isoquinolines,
isochromenes
and
isocarbostyrils.[8] Thus great efforts have been contributed and
plenty of documentation has been delivered towards the
versatile molecules. Conventionally, pre-activated substrates
including haloed molecules were coupled with unsaturated
partners like acetylenes[9], allenes[10] and etc.[11] Subsequently,
decarbonylative[12] or decarboxylative[13] addition/annulation
reactions were discovered which were realized in the presence
of Rh or Ni catalysts. However, the requirement of multiple steps
or usage of stoichiometric amount of external metallic oxidants
led to low efficiency and poor atom/step economy, which
restricted the traditional synthetic methodologies for general
applications. Thus, novel strategies involving C-H bond
activation and successive functionalization, which have been
well-developed for the formations of carbon-carbon bonds[14] and
carbon-hetero bonds,[15] were turned to for the construction of
isocoumarin derivatives.[16] Pioneered by Miura[17] and
Ackermann,[18] reactions between benzoic acids and
intermediate acetylenes were demonstrated in the presence of
rhodium, ruthenium catalysts with Cu(II) or Ag(I) salts used as
external oxidant.[19,20] However, phthalides and naphthalenes[19]
were also obtained as side-products due to low regio-selectivity
or catalytic efficiency. Recently, the emergence of various
reports using N-O bonds,[21] O-O bonds[22] as internal oxidants or
other external oxidants have enriched the diversity of the
transformations towards the pivotal molecules. Based on the
Scheme 1. Strategies for the synthesis of isocoumarins
Results and Discussion
Firstly, reactions between benzoic acid (1a) and P-(2-
phenylethynyl) diethyl phosphonate (2a) were carried out for the
optimal conditions as summarized in Table 1. In the presence of
(Cp*RhCl2)2 as the catalyst and Cu(OAc)2·H2O as the oxidant,
the reaction took place smoothly in DMF (N,N-dimethyl
formamide) at 120 oC, and 48% of the desired annulated product
(3aa) was isolated after 24 hours (entry 1). Further optimization
was embarked and it was found that CH3OH offered the best
performance for the annulation reaction and 78% yield of 3aa
was obtained (entry 2). Other solvents such as DCE (1,2-
dichloromethane), acetonitrile and dioxane produced 3aa in poor
to medium yields, ranging from 18% to 55% (entries 3 – 5).
While DMSO (dimethyl sulfoxide) and toluene showed no effect
for the transformation for no reaction was detected after 24
hours (entries 6 and 7). Similarly, tert-amyl alcohol made the
reaction happen and 3aa was successfully isolated in 72% yield,
lower than in MeOH (entry 8). Also, the reaction temperature
was significant to the efficiency of the reaction. Decreased
temperature led to lower yields (entries 9 and 10) or even no
reaction was observed when the reaction was conducted at 60
State Key Laboratory of Chemo/Biosensing and Chemometrics, College of
Chemistry and Chemical Engineering
Hunan University
Changsha, 410082, P. R. of China.
Tel. (Fax):+86 731 88821380
E-mail: wanrongdong@hnu.edu.cn; pzh7251@hnu.edu.cn;
deliean@hnu.edu.cn
Supporting information for this article is given via a link at the end of the
document.
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European Journal of Organic Chemistry
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FULL PAPER
oC (entry 11). On the other hand, it was noticed that organic or
21h)
--
--
CH3OH
n.r.
inorganic oxidants like TBHP (tert-butyl hydroperoxide, 70% in
a)
Reaction conditions: 1a (0.3 mmol), 2a (0.45 mmol), cat. (5.0 mol%),
water), DTBP (di-tert-butyl peroxide), K2S2O8 and Fe(OAc)2
-
additive or oxidant (0.6 mmol otherwise noted) under air atmosphere or
failed to prompt the reaction for no reaction was detected
(entries 12 – 15). But usage of the silver salts AgSbF6 led to the
formation of 3aa in 46% yield (entry 16), inferior to entry 1. To
our delight, when the reaction was performed with assistance of
50 mol% NaOAc under dioxygen atmosphere, the yield of the
expected product 3aa was dramatically elevated up to 81% after
fully consumption of 1a within 16 hours (entry 17).
Disappointingly, other rhodium catalyst or palladium catalysts
acted worse in the system (entries 18 – 20). No product was
detected without either the catalyst or the additive (entry 21).
d)
noted, at 120 oC for 24 h. b) Isolated yields. c) n.r. stands for no reaction.
The reaction was performed at 100 oC. e) The reaction was performed at 80
oC. f) The reaction was performed at 60 oC. g) NaOAc (0.15 mmol) under O2
atmosphere for 16 h was used instead of Cu(OAc)2 (0.6 mmol) under air
atmosphere for 24 h. h) The reaction was conducted in the abesence of either
the catalyst or the additive.
With the optimal conditions in hand, the scope and limitations of
the substrate were evaluated. Under the optimal conditions, 4-
methyl benzoic acid (1b) reacted with P-(2-phenylethynyl)-
diethyl phosphonate 2a readily, furnishing the desired 3-(diethyl
phosphoryl)-4-phenyl-6-methyl-1H-2-benzopyran-1-one 3ba as
the product in 79% yield (entry 1). However, ortho-substituted
aryl carboxylic acid exhibited negative effect to the annulation
reaction. For example, only medium yields were obtained when
2-methyl benzoic acid (1c) and 2,3-dimethyl benzoic acid (1d)
were employed for coupling with 2a, 62% and 64% for 3ca and
3ba, respectively (entries 2 and 3). Methoxy group decorated
carboxylic acids on the para-position provided the corresponding
3-phosphoryl substituted isocoumarin 3ea in 83% yield (entry 4).
The occupation on the meta-position did not affect the efficiency
of the transformation severely for 3-(diethyl phosphoryl)-4-
Table 1. Optimization of the reaction conditions[a]
Entry
1
Cat.
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
(Cp*RhCl2)2
Cp*Rh(MeCN)3(SbF6
Add./[O]
Cu(OAc)2·H2O
Cu(OAc)2·H2O
Cu(OAc)2·H2O
Cu(OAc)2·H2O
Cu(OAc)2·H2O
Cu(OAc)2·H2O
Cu(OAc)2·H2O
Cu(OAc)2·H2O
Cu(OAc)2·H2O
Cu(OAc)2·H2O
Cu(OAc)2·H2O
TBHP
Sol.
DMF
Yield b)
48%
78%
18%
55%
38%
n.r.c)
trace
72%
58%
30%
n.r.
phenyl-6,7-dioxolo-1H-2-benzopyran-1-one
(3fa)
was
2
CH3OH
DCE
successfully furnished in 80% yield, close to that of entry 4
(entry 5). Additionally, the compatibilities of the halogen groups
on the aryl carboxylic acid were also tested in the rhodium-
catalyzed protocol. Pleasingly, 4-fluoro benzoic acid (1g)
coupled smoothly with 2a, and fluorinated isocoumarin 3ga was
offered in 82% yield (entry 6). However, installation of other halo
groups showed slightly lower efficiency for the formation of the
corresponding isocoumarin derivatives, and yields ranging from
75% to 78% were recorded for 3ha – 3ja (entries 7 – 9). Polyaryl
and heteroaryl carboxylic acids were also well-tolerated in the
system. For instance, 2-naphthoic acid (1k) and 2-thenoic acid
(1l) underwent the annulation reaction smoothly, and the desired
molecules 3ka and 3la were successfully provided in 79% and
70% yields, separately (entries 10 and 11).
3
4
MeCN
5
dioxane
DMSO
toluene
t-AmylOH
CH3OH
CH3OH
CH3OH
CH3OH
CH3OH
CH3OH
CH3OH
CH3OH
CH3OH
6
7
8
9d)
10e)
11f)
12
13
14
15
16
17g)
Table 2. Substrates scope of the aryl carboxylic acidsa)
trace
trace
n.r.
DTBP
K2S2O8
Fe(OAc)2
trace
46%
81%
AgSbF6
Entry
1
3
Ar
Yield b)
79%
NaOAc/O2
1
2
3
4
1b
1c
1d
1e
3ba
3ca
3da
3ea
4-CH3C6H4
2-CH3C6H4
2,3-(CH3)2C6H3
4-CH3OC6H4
18
NaOAc/O2
CH3OH
42%
62%
)
2
64%
19
20
Pd(OAc)2
NaOAc/O2
NaOAc/O2
CH3OH
CH3OH
n.r.
n.r.
83%
Pd(PPh3)2Cl2
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European Journal of Organic Chemistry
10.1002/ejoc.201601330
FULL PAPER
2
3
4
1a/2c
1a/2d
1i/2e
3ac
3ad
3ie
3-CH3Ph
4-CH3OPh
Et
Et
Et
78%
79%
81%
5
1f
3fa
80%
2,5-(CH3O)2Ph
6
7
1g
1h
1i
3ga
3ha
3ia
4-FC6H4
4-ClC6H4
82%
78%
75%
77%
79%
70%
8
4-BrC6H4
4-IC6H4
5
1a/2f
3af
80%
9
1j
3ja
10
11
1k
1l
3ka
3la
2-Naphthyl
2-Thiophenyl
6
7
1a/2g
1a/2h
1a/2i
1a/2j
1a/2k
1a/2l
3ag
3ah
3ai
4-ClPh
2-Naphthyl
2-Thiophenyl
Ph
Et
Et
85%
75%
72%
72%
80%
79%
a)
Reaction conditions: 1 (0.5 mmol), 2a (0.75 mmol), (Cp*RhCl2)2 (5.0 mol%),
NaOAc (0.25 mmol) under O2 atmosphere at 120 oC for 16 h. b) Isolated yields.
8
Et
9
3aj
Me
iPr
nBu
Then, the tolerance of the functional groups on alkynyl
phosphonates was also tested in the system as shown in Table
3. To our satisfaction, P-[2-(4-methylphenyl)-ethynyl] diethyl
phosphonate (2b) reacted with benzoic acid (1a) readily,
furnishing the corresponding 3-phosphoryl isocoumarin 3ab in
81% yield (entry 1). By comparison, variation of the methyl
group on the phenyl group did not affect the efficiency of the
protocol for P-[2-(3-methylphenyl)-ethynyl] diethyl phosphonate
(2c) afforded the relevant product in the same manner, but in
78% yield (entry 2). Meanwhile, methoxy or dimethoxy
substituted phenyl groups were also compatible in the system,
which were well exemplified by P-[2-(4-methoxyphenyl)-ethynyl]
phosphonic diethyl ester (2d), [2-(2,5-dimethoxyphenyl)-ethynyl]
phosphonic diethyl ester (2e) and P-[2-(1,3-benzodioxol-5-yl)
ethynyl]- phosphonic diethyl ester (2f) (entries 3 – 5). Reactions
between 2e – 2g and 1a or 1i took place smoothly, approaching
the desired isocoumarin derivatives 3ad, 3ie and 3af in yields
from 79% - 81%. Haloed phosphonate like P-[(4-chlorophenyl)
ethynyl] diethyl phosphonate (2g) coupled with 1a successfully
in the presence of the rhodium catalyst, providing the
isocoumarin derivative 3ag in 85% yield (entry 6). Polyaryl and
heteroaryl like 2-naphthyl and 2-thiophenyl decorated alkynyl
diethyl phosphonates 2h and 2i produced the corresponding
phosphoryl fused isocoumarins in 75% and 72% yields (entries 7
and 8). Except for diethyl phosphonates, dimethyl (entry 9), di-
isopropyl (entry10) and di-n-butyl (entry 11) phosphonates 2j –
2l were well-tolerated in the system and gave the adducts 3aj –
3al in yields ranging from 72% to 80%.
10
11
3ak
3al
Ph
Ph
a)
Reaction conditions: 1a or 1i (0.5 mmol), 2 (0.75 mmol), (Cp*RhCl2)2 (5.0
mol%), NaOAc (0.25 mmol) under O2 atmosphere at 120 oC for 16 h.
Isolated yields.
b)
Encouraged by the good compatibilities of the rhodium-
catalyzed protocol, the broader scope of the substrates was then
investigated on other alkynyl derivatives as shown in Table 4.
For example, the reactivity of yamines and alkynyl esters also
was evaluated in the practical methodology. Under the optimal
conditions, benzoic acid (1a), 4-methyl benzoic acid (1b) and 4-
methoxy benzoic acid (1e) reacted with 3-phenyl-2-propynoic
ethyl ester (4a) readily, furnishing the corresponding aryl-1-oxo-
1H-2-benzopyran-3-carboxylic ethyl ester 6aa – 6ca in yields
from 80% to 83%. Heteroaryl carboxylic acid such as 2-thenoic
acid (1l) offered 4-phenyl-1-oxo-1H-thienopyran-3-carboxylic
ethyl ester (6la) in 80% yield. In the same way, 4-phenyl-1-oxo-
1H-2-benzopyran-3-carboxylic methyl ester (6ab) and 4-(4-
methylphenyl-1-oxo-1H-2-benzopyran-3-carboxylic methyl ester
(6ac) were synthesized in 82% and 86% yields, separately.
When the representative yamines such as 3-alkynyl-2-
oxazolidinones were used as the coupling partner in the system
with aryl carboxylic acids, the protocol exhibited good efficiency.
As shown in Table 4, diverse 3-(2-Oxo-3-oxazolidinyl) 1H-2-
benzopyran-1-ones 7aa – 7ad and 7ba, 7la were provided from
the Rh(III)-catalyzed strategy in yields from 80% - 88%.
Table 3. Substrates scope on alkynyl phosphonatesa)
Table 4. Substrates scope on alkynyl esters and yaminesa)
Entry
1
1/2
3
Ar
R’
Yieldb)
1a/2b
3ab
4-CH3Ph
Et
81%
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European Journal of Organic Chemistry
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a)
Scheme 2. Proposed mechanism
Reaction conditions: 1a (0.5 mmol), 4 or 5 (0.75 mmol), (Cp*RhCl2)2 (5.0
mol%), NaOAc (0.25 mmol) under O2 atmosphere at 120 oC for 16 h.
Conclusions
Additionally, the structure of 3ja was unequivocally determined
by single crystal X-ray diffraction, which was obtained from
methanol (Figure 1).[25]
In conclusion, a rhodium catalysed annulation reaction was
developed for the formation of novel hetero substituted
isocoumarins. The methodology was featured for the high
atom/step efficiency and high regio-selectivity and broad
substrate scope. In addition, oxygen played an important role in
the protocol as clean oxidant. Further systemic investigations on
the isocoumarin derivatives are still in progress in our laboratory.
Experimental Section
General Remarks: All carboxylic reagents were purchased from
commercial companies and used without further purification, alkynyl
phosphonates and yamines were prepared by the methods described in
reported literatures[24b,26] 1H and 13C NMR spectra were recorded on a
.
Varian INOVA-400 spectrometer in deuterated chloroform at 25 °C with
residue solvent peaks as internal standards ( = 7.26 ppm for 1H-NMR
and  = 77.16 ppm for 13C-NMR). Chemical shifts () are reported in ppm,
and spin-spin coupling constants (J) are given in Hz, while multiplicities
are abbreviated by s (singlet), d (doublet), t (triplet), q (quartet) and m
(multiplet). Mass spectra were recorded on a ThermoFinnigan MAT95XP
microspectrometer and High resolution mass spectra (HRMS) were
recorded on an Agilent Technologies Accurate Mass Q-TOF 6530
microspectrometer. Infrared (IR) spectra were reported in reciprocal
centimeter (cm-1). Melting points were recorded on a national standard
melting point apparatus (Model: Taike XT-4) and were uncorrected.
Figure 1. ORTEP diagram of the X-ray crystal structure of 3ja (Thermal
ellipsoids are drawn at 30% probability)
Based on the disclosed precedents, the mechanism of the
annulation protocol was proposed (Scheme 2). Initially, the
dimer (Cp*RhCl2)2 was transformed into singlet rhodium species
Cp*Rh(III) of higher activity. Then, oxidative insertion of the
Rh(III) on the ortha-C-H bond took place, leading to a five-
membered rhodacycle I with assistance of the carboxylic group.
Successive coupling of the alkynyl substrate 2a with I gave two
optional accesses to novel seven-member rhodacyclic
intermediate II and II'. But the formation of II was favourable
while II' was disfavoured due to the difference of the electronic
density on the two alkynyl carbon atoms, which made a good
illustration for the high regio-selectivity. Finally, the product 3aa
was afforded by a reductive elimination step with a release of
Cp*Rh(I), which was then re-oxided into Cp*Rh(III) by the
molecular oxygen for the completion of the catalytic cycle.
General Procedure: A sealed tube (35 mL) equipped with a stirring bar
was charged with oxygen for three times and then was loaded with aryl
carboxylic acid (0.5 mmol), alkynyl (0.75 mmol), NaOAc (0.25 mmol) and
(Cp*RhCl2)2 (5 mol%) and the reaction mixture was allowed to stir at
120 °C for 16 h. After cooling to room temperature, the mixture was
filtered through a short celite pad and washed with dichloromethane (15
mL  3). The filtrate was concentrated and the oily crude product was
purified by column chromatography using silica gel (200-300 mesh) as
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European Journal of Organic Chemistry
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FULL PAPER
stationary phase and a mixture of petroleum and ethyl acetate as eluent
to give the desired product 3, 6 and 7 in noted yields.
1H), 4.12 – 4.01 (m, 2H), 3.99 – 3.89 (m, 2H), 3.72 (s, 3H), 1.21 (t, J =
7.1 Hz, 6H) (ppm). 13C NMR (100 MHz, CDCl3)  = 164.8 (JC-P = 1.2 Hz),
160.6 (JC-P = 9.0 Hz), 140.0 (JC-P = 14.7 Hz), 132.4, 132.2, 130.6 (JC-P
=
1.4 Hz), 128.9, 128.5, 127.8 (JC-P = 15.5 Hz), 127.5, 117.4, 115.1, 110.0,
63.53, 63.47, 55.7, 16.30, 16.23 (ppm). 31P NMR (160 MHz, CDCl3)  =
4.12 (ppm). IR (in KBr) v = 3456, 2983, 2929, 2933, 2862, 1734, 1602,
1563, 1487, 1446, 1359, 1313, 1263, 1224, 1163, 1132, 1105, 1022, 972,
808, 756, 707 (cm-1). MS (EI): m/z(%) = 121.2 (62), 152.2 (56), 195.2
(54), 251.2 (100), 388.2 (100, M+). HRMS (EI) (m/z) [C20H21O6P]+: Calcd.
388.1076, Found.388.1061.
3-(Diethyl
phosphoryl)-4-phenyl-1H-2-benzopyran-1-one
(3aa):
1
colorless oil (150.0 mg, 81% yield). H NMR (400 MHz, CDCl3)  = 8.36
(d, J = 7.6 Hz, 1H), 7.62 (m, 2H), 7.48 (d, J = 6.7 Hz, 3H), 7.36 (dd, J =
7.3, 2.0 Hz, 2H), 7.06 (d, J = 7.9 Hz, 1H), 4.13 – 4.02 (m, 2H), 3.99 –
3.88 (m, 2H), 1.20 (t, J = 7.1 Hz, 6H) (ppm). 13C NMR (100 MHz, CDCl3)
 = 160.7 (JC-P = 9.0 Hz), 145.6, 143.2, 137.2 (JC-P = 14.5 Hz), 134.9,
132.2 (JC-P = 2.6 Hz), 130.6 (JC-P = 1.5 Hz), 130.2, 129.7, 128.8, 128.5,
127.8 (JC-P = 20.2 Hz), 126.6 (JC-P = 1.4 Hz), 122.0, 63.5, 63.4, 16.3, 16.2
(ppm). 31P NMR (160 MHz, CDCl3)  = 4.07 (ppm). IR (in KBr)  = 3464,
2983, 2933, 2910, 2872, 1739, 1600, 1481, 1448, 1392, 1371, 1263,
1203, 1166, 1128, 1101, 1026, 975, 800, 752, 700 (cm-1). MS (EI):
m/z(%) = 121.1 (100), 139.1 (10), 165.1 (78), 193.1 (24), 221.1 (50),
358.1 (52, M+). HRMS (EI) (m/z) [C19H19O5P]+: Calcd. 358.0970, Found
358.0975.
3-(Diethyl phosphoryl)-4-phenyl-6,7-dioxolo-1H-2-benzopyran-1-one
o
(3fa): yellow solid (160.8 mg, 80% yield). m.p.: 170 – 172 C. 1H NMR
(400 MHz, CDCl3)  = 8.03 (d, J = 8.4 Hz, 1H), 7.38 (d, J = 2.0 Hz, 5H),
7.06 (d, J = 8.3 Hz, 1H), 5.79 (s, 2H), 4.08 – 4.02 (m, 2H), 3.95 – 3.88 (m,
2H), 1.20 (d, J = 7.0 Hz, 6H) (ppm). 13C NMR (100 MHz, CDCl3)  =
164.7 (JC-P = 6.7 Hz), 160.2, 153.6, 145.7, 143.8, 133.1, 130.6, 130.4,
128.9, 128.6, 127.8, 126.4, 124.6, 124.4, 120.0 (JC-P = 15.8 Hz), 111.1,
102.6, 63.6, 63.5, 16.32, 16.26 (ppm). 31P NMR (160 MHz, CDCl3)  =
4.31 (ppm). IR (in KBr) v = 3446, 2981, 2926, 2864, 1760, 1618, 1570,
1496, 1479, 1454, 1167, 1274, 1201, 1155, 1130, 1082, 1026, 987, 935,
800, 752, 723, 700 (cm-1). MS (EI): m/z(%) = 121.1 (100), 151.1 (28),
237.0 (26), 265.0 (68), 402.0 (85, M+). HRMS (ESI) (m/z) [C20 H19O7
P+H+]: Calcd. 403.0941, Found.403.0940.
3-(Diethyl
phosphoryl)-4-phenyl-6-methyl-1H-2-benzopyran-1-one
(3ba)：white solid (146.9 mg, 79% yield). m.p.:102 – 104 oC. 1H NMR
(400 MHz, CDCl3)  = 8.25 (d, J = 8.1 Hz, 1H), 7.49 (d, J = 6.7 Hz, 3H),
7.38 (dd, J = 19.6, 7.3 Hz, 3H), 6.81 (s, 1H), 4.12 – 4.01 (m, 2H), 4.00 –
3.88 (m, 2H), 2.35 (s, 3H), 1.21 (t, J = 7.1 Hz, 6H) (ppm). 13C NMR (100
MHz, CDCl3)  = 160.8 (JC-P = 9.0 Hz), 146.2, 145.7, 143.3, 137.3, 132.3,
131.4, 130.7, 129.8, 128.8, 128.5, 127.8 (JC-P = 20.1 Hz), 127.7, 127.5,
126.6, 119.6, 63.5, 63.4, 22.2, 16.3, 16.2 (ppm). 31P NMR (160 MHz,
CDCl3)  = 4.21 (ppm). IR (in KBr) v = 3479, 2983, 2929, 2908, 1741,
1701, 1610, 1489, 1444, 1392, 1340, 1307, 1255, 1224, 1174, 1132,
1116, 1099, 1026, 1026, 975, 958, 810, 783, 763, 750, 702 (cm-1). MS
(EI): m/z(%) = 121.2 (69), 179.2 (68), 207.2 (30), 235.2 (84), 372.3 (100,
M+). HRMS (EI) (m/z) [C20H21O5P]+: Calcd. 372.1127, Found. 372.1116.
3-(Diethyl
phosphoryl)-4-phenyl-6-fluoro-1H-2-benzopyran-1-one
(3ga): white solid (154.1 mg, 82% yield). m.p.: 112 – 114 C. 1H NMR
(400 MHz, CDCl3)  = 8.38 (dd, J = 8.8, 5.6 Hz, 1H), 7.50 – 7.45 (m, 3H),
7.34 (dd, J = 7.1, 2.2 Hz, 2H), 7.24 (s, 1H), 6.68 (dd, J = 9.6, 2.4 Hz, 1H),
4.10 – 4.02 (m, 2H), 3.97 – 3.89 (m, 2H), 1.19 (t, J = 7.1 Hz, 6H) (ppm).
13C NMR (100 MHz, CDCl3)  = 168.1 (JC-P = 1.0 Hz), 159.9 (JC-P = 7.0
Hz), 147.1, 144.8 ( JC-P = 2.0 Hz), 133.2, 133.1, 131.8, 131.7, 130.6 ( JC-P
o
= 2.0 Hz), 129.2, 128.8, 128.0, 118.5, 118.5 ( JC-P = 3.0 Hz), 113.0 (JC-P
=
3-(Diethyl
phosphoryl)-4-phenyl-8-methyl-1H-2-benzopyran-1-one
1.0 Hz), 112.8 (JC-P = 1.0 Hz), 63.73, 63.67, 16.33, 16.26 (ppm). 31P
NMR (160 MHz, CDCl3)  = 3.59 (ppm). 19F NMR (375 MHz, CDCl3)  =
-100.07 (ppm). IR (in KBr) v = 2983, 2931, 1739, 1608, 1560, 1483,
1442, 1255, 1120, 1099, 1029, 974, 756, 700 (cm-1). MS (EI): m/z(%) =
93.0 (52), 121.1 (94), 183.0 (100), 211.0 (31), 239.0 (86), 376.0 (60, M+).
HRMS (EI) (m/z) [C19H18FO5P]+: Calcd. 376.0876, Found.376.0867.
(3ca): yellow solid (115.3 mg, 62% yield). m.p.: 82 – 84 oC. 1H NMR (400
MHz, CDCl3)  = 7.57 – 7.43 (m, 4H), 7.37 (dd, J = 15.0, 6.9 Hz, 3H),
6.88 (d, J = 7.9 Hz, 1H), 4.15 – 4.02 (m, 2H), 4.02 – 3.87 (m, 2H), 2.87 (s,
3H), 1.22 (t, J = 7.0 Hz, 6H) (ppm). 13C NMR (100 MHz, CDCl3)  = 160.1
(JC-P = 9.0 Hz),145.4, 143.9, 138.9, 138.8, 134.1, 133.2, 132.9 (JC-P = 2.6
Hz), 130.8, 128.8, 128.5, 128.0, 127.8, 125.0, 120.5, 63.52, 63.46, 23.6,
16.32, 16.25 (ppm). 31P NMR (160 MHz, CDCl3)  = 4.16 (ppm). IR (in
KBr) v = 3059, 2981, 2926, 2858, 1735, 1586, 1467, 1388, 1263, 1228,
1159, 1097, 1049, 1020, 972, 810, 754, 702 (cm-1). MS (EI): m/z(%) =
93.0 (44), 121.1 (100), 179.0 (70), 236.1 (38), 372.0 (66, M+). HRMS
(ESI) (m/z) [C20H21O5P+H+]: Calcd. 373.1199, Found.373.1201.
3-(Diethyl
phosphoryl)-4-phenyl-6-chloro-1H-2-benzopyran-1-one
(3ha)：yellow solid (152.8 mg, 78% yield). m.p.: 158 – 160 C. 1H NMR
(400 MHz, CDCl3)  = 8.31 (d, J = 8.5 Hz, 1H), 7.61 – 7.47 (m, 4H), 7.36
(dd, J = 7.0, 2.2 Hz, 2H), 7.02 (d, J = 1.9 Hz, 1H), 4.13 – 4.05 (m, 2H),
4.00 – 3.89 (m, 2H), 1.21 (t, J = 7.1 Hz, 6H) (ppm). 13C NMR (100 MHz,
CDCl3)  = 160.1 (JC-P = 13.0 Hz), 160.0, 147.2, 144.9, 142.1, 138.9,
138.8, 131.6 (JC-P = 2.0 Hz), 130.7(JC-P = 1.2 Hz), 129.2, 128.8, 126.8,
o
3-(Diethyl
phosphoryl)-4-phenyl-7,8-dimethyl-1H-2-benzopyran-1-
one (3da): yellow solid (123.8 mg, 64% yield). m.p.: 58 – 60 oC. 1H NMR
(400 MHz, CDCl3)  = 7.46 (d, J = 6.6 Hz, 3H), 7.39 (d, J = 8.2 Hz, 1H),
7.36 – 7.29 (m, 2H), 6.77 (d, J = 8.2 Hz, 1H), 4.12 – 4.01(m, 2H), 3.99 –
3.89 (m, 2H), 2.81 (s, 3H), 2.40 (s, 3H), 1.21 (t, J = 7.1 Hz, 6H) (ppm).
13C NMR (100 MHz, CDCl3)  = 160.5 (JC-P = 9.0 Hz), 144.4, 142.0 (JC-P
= 3.9 Hz), 140.1, 136.8 ( JC-P = 14.2 Hz), 136.1, 132.9 (JC-P = 2.6 Hz),
130.8 (JC-P = 1.4 Hz), 128.6, 128.4, 128.2, 124.2 ,120.5, 63.4, 63.3, 21.3,
18.0, 16.3, 16.2 (ppm). 31P NMR (160MHz, CDCl3)  = 4.37 (ppm). IR (in
KBr) v = 3479, 2981, 2927, 2868, 1732, 1712, 1556, 1475, 1444, 1392,
1259, 1165, 1111, 1049, 1024, 1001, 977, 750 (cm-1). MS (EI): m/z(%) =
121.1 (98), 193.1 (56), 221.1 (44), 249.1 (47), 386.0 (100, M+). HRMS
(ESI) (m/z) [C21H23O5P+H+]: Calcd. 387.1356, Found.387.1354.
126.6, 126.3, 120.3 (JC-P = 2.0 Hz), 63.74, 63.68, 16.33, 16.27 (ppm). 31
P
NMR (160 MHz, CDCl3)  = 3.56 (ppm). IR (in KBr) v = 3730, 2924, 2862,
1739, 1546, 1514, 1336, 1265, 1259, 1193, 1029, 958, 752, 698, 669
(cm-1). MS (EI): m/z(%) = 93.0 (45), 121.1 (100), 199.0 (48), 255.0 (35),
392.0 (7, M+). HRMS (ESI) (m/z) [C19H18ClO5P+H+]: Calcd. 393.0653,
Found.393.0657.
3-(Diethyl phosphoryl)-4-phenyl-6-bromo -1H-2-benzopyran-1-one
(3ia)：yellow solid (163.5 mg, 75% yield). m.p.: 170 – 172 oC. 1H NMR
(400 MHz, CDCl3)  = 8.23 (d, J = 8.4 Hz, 1H), 7.72 (dd, J = 8.4, 1.5 Hz,
1H), 7.52 (dd, J = 7.9, 2.8 Hz, 3H), 7.41 – 7.33 (m, 2H), 7.19 (d, J = 1.4
Hz, 1H), 4.15 – 4.03 (m, 2H), 4.01 – 3.89 (m, 2H) , 1.21 (t, J = 7.1 Hz, 6H)
(ppm). 13C NMR (100 MHz, CDCl3)  = 160.2 (JC-P = 9.0 Hz), 147.1,
3-(Diethyl phosphoryl)-4-phenyl-6-methoxyl-1H-2-benzopyran-1-one
(3ea): white solid (161.0 mg, 83% yield). m.p.: 114 – 116 oC. 1H NMR
(400 MHz, CDCl3)  = 8.30 (d, J = 8.8 Hz, 1H), 7.47 (t, J = 6.3 Hz, 3H),
7.41 – 7.34 (m, 2H), 7.11 (dd, J = 8.8, 2.4 Hz, 1H), 6.42 (d, J = 2.3 Hz,
144.8, 138.9, 138.8, 133.6, 131.5 (JC-P = 2.0 Hz), 131.4, 130.7 ( JC-P
=
=
2.0 Hz), 129.4 ( JC-P = 2.0 Hz), 129.3, 128.8, 126.7,127.1, 120.7 (JC-P
1.0 Hz), 63.8, 63.7, 16.33, 16.27 (ppm). 31P NMR (160 MHz, CDCl3)  =
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European Journal of Organic Chemistry
10.1002/ejoc.201601330
FULL PAPER
3.53 (ppm). IR (in KBr) v = 2980, 2924, 2860, 1737, 1544, 1263, 1031,
754, 696, 667 (cm-1). MS (EI): m/z(%) = 93.0 (39), 121.1 (100), 163.1
(35), 243.0 (20), 300 (39), 437.9 (31, M+). HRMS (EI) (m/z)
[C19H18BrO5P]+: Calcd. 436.0075, Found.436.0063.
4.11 – 4.01 (m, 2H), 3.99 – 3.89 (m, 2H) , 2.39 (s, 3H), 1.20 (t, J = 7.1 Hz,
6H) (ppm). 13C NMR (100 MHz, CDCl3)  = 160.9 (JC-P = 9.0 Hz), 145.6,
143.2, 138.2, 137.9, 137.5, 137.4, 137.3, 134.9, 132.1, 132.0, 131.3,
130.2, 129.7 (JC-P = 13.3 Hz), 128.4, 127.8, 126.8, 122.1, 63.6, 63.5, 21.6,
16.31, 16.26 (ppm). 31P NMR (160 MHz, CDCl3)  = 4.19 (ppm). IR (in
KBr) v = 3448, 2966, 2929, 2864, 1939, 1639, 1327, 1265, 1165, 1024,
975, 798, 756, 702 (cm-1). MS (EI): m/z(%) = 93.1 (62), 121.1 (100),
235.1 (60), 372.1 (37, M+). HRMS (ESI) (m/z) [C20H21O5P+H+]: Calcd.
373.1199, Found. 373.1203.
3-(Diethyl phosphoryl)-4-phenyl-6-iodo-1H-2-benzopyran-1-one (3ja):
white solid (186.3mg, 77% yield). m.p.: 188 – 190 oC. 1H NMR (400 MHz,
CDCl3)  = 8.05 (d, J = 8.3 Hz, 1H), 7.94 (d, J = 8.3 Hz, 1H), 7.51 (d, J =
5.6 Hz, 3H), 7.39 (s, 1H), 7.35 (d, J = 7.6 Hz, 2H), 4.10 – 4.03 (m, 2H),
4.02 – 3.83 (m, 2H), 1.22 (t, J = 7.1 Hz, 6H) (ppm). 13C NMR (100 MHz,
CDCl3)  = 160.5 (JC-P =9.0 Hz), 144.6, 139.4, 138.6, 138.4, 135.5 (JC-P
=2.0 Hz), 131.5 (JC-P = 3.0 Hz), 130.6 (JC-P = 2.0 Hz), 129.2, 128.8, 126.5,
126.3, 121.2 (JC-P = 1.0 Hz), 103.7 (JC-P =2.0 Hz), 63.72, 63.66, 16.32,
16.25 (ppm). 31P NMR (160 MHz, CDCl3)  = 3.56 (ppm). IR (in KBr) v =
2981, 2926, 2858, 1737, 1583, 1394, 1259, 1193, 1031, 752, 700 (cm-1).
MS (EI): m/z(%) = 93.0 (55), 121.1 (100), 163.1 (40), 346.9 (38), 483.9
(36, M+). HRMS (ESI) (m/z) [C19H18IO5P+H+]: Calcd. 485.0009,
Found.485.0008.
3-(Diethyl phosphoryl)-4-(4-methoxyphenyl)-1H-2-benzopyran-1-one
1
(3ad): colorless oil (153.3 mg, 79% yield). H NMR (400 MHz, CDCl3) 
= 8.37 (d, J = 7.7 Hz, 1H), 7.63 (dd, J = 17.7, 7.6 Hz, 2H), 7.29 (d, J = 8.2
Hz, 2H), 7.12 (d, J = 7.9 Hz, 1H), 7.01 (d, J = 8.2 Hz, 2H), 4.15 – 4.05 (m,
2H), 4.02– 3.94 (m, 2H), 3.87 (s, 3H), 1.25 (d, J = 6.9 Hz, 6H) (ppm). 13
C
NMR (100 MHz, CDCl3)  = 160.9 (JC-P = 9.0 Hz), 160.8, 160.1, 137.7,
137.5, 134.9, 131.9, 130.1, 129.7, 127.6, 126.7 (JC-P = 1.2 Hz), 124.1,
122.1, 114.0, 63.6, 63.5, 55.4, 16.4, 16.3 (ppm). 31P NMR (160 MHz,
CDCl3)  = 4.22 (ppm). IR (in KBr) v = 3396, 2962, 2923, 1741, 1604,
1512, 1259, 1098, 1023, 799, 698, 567 (cm-1). MS (EI): m/z(%) = 93.1
(45), 121.1 (100), 152.1 (37), 388.0 (49, M+). HRMS (EI) (m/z)
[C20H21O6P]+: Calcd. 388.1076, Found.388.1064.
3-(Diethyl phosphoryl)-4-phenyl-1H-naphtho[2, 3-c]pyran -1-one
1
(3ka): colorless oil (161.2 mg, 79% yield). H NMR (400 MHz, CDCl3) 
= 8.38 (d, J = 8.6 Hz, 1H), 8.04 (s, 1H), 7.86 (s, 1H), 7.49 (dd, J = 21.1,
7.1 Hz, 6H), 7.13 (dd, J = 20.6, 7.9 Hz, 2H), 4.14 – 4.04 (m, 2H), 4.03 –
3.93 (m, 2H), 1.26 (t, J = 7.2 Hz, 6H) (ppm). 13C NMR (100 MHz, CDCl3)
 = 161.4 (JC-P = 9.0 Hz), 144.9, 137.4, 132.2, 131.2 (JC-P = 1.0 Hz),
130.8 (JC-P = 2.0 Hz), 129.7, 129.6, 129.3, 129.2, 128.9, 128.8, 128.7,
128.6, 128.0, 127.9, 127.6, 126.7 (JC-P = 3.0 Hz), 124.3, 63.64, 63.58,
16.4, 16.3 (ppm). 31P NMR (160 MHz, CDCl3)  = 4.71 (ppm). IR (in KBr)
v = 3443, 2956, 2924, 1730, 1640, 1606, 1446, 1376, 1248, 1023, 797,
762, 579, 528 (cm-1). MS (EI): m/z(%) = 93.0 (42), 121.1 (100), 215.1
(75), 270.1 (45), 408.1 (83, M+). HRMS (EI) (m/z) [C23H21O5P]+: Calcd.
408.1127, Found.408.1124.
3-(Diethyl
phosphoryl)-4-(2,5-dimethoxyphenyl)-6-bromo-1H-2-
benzopyran-1-one (3ie): yellow solid (200.8 mg, 81% yield). m.p.: 118 –
120 oC. 1H NMR (400 MHz, CDCl3)  = 8.20 (d, J = 8.4 Hz, 1H), 7.69 (dd,
J = 8.4, 1.4 Hz, 1H), 7.14 (d, J = 1.3 Hz, 1H), 6.97 (dd, J = 17.7, 5.9 Hz,
2H), 6.85 (d, J = 2.9 Hz, 1H), 4.21 – 4.13 (m, 2H), 4.03 – 3.86 (m, 2H),
3.80 (s, 3H), 3.69 (s, 3H), 1.31 (t, J = 7.1 Hz, 3H), 1.17 (t, J = 7.1 Hz, 3H)
(ppm). 13C NMR (100 MHz, CDCl3)  = 160.4 (JC-P = 9.0 Hz), 153.6,
151.8, 147.1, 144.8, 138.5, 138.3, 133.4, 131.2, 130.6 (JC-P = 1.4 Hz),
129.1 (JC-P = 1.5 Hz), 121.1(JC-P = 2.5 Hz), 120.7 (JC-P = 1.3 Hz), 118.0,
115.8, 112.1 , 63.9, 63.8, 63.34, 63.28, 56.2, 55.9, 16.42, 16.36, 16.3,
16.2 (ppm). 31P NMR (160 MHz, CDCl3)  = 3.31 (ppm). IR (in KBr) v =
3560, 3458, 2929, 2837, 1739, 1589, 1498, 1465, 1398, 1269, 1226,
1166, 1130, 1024, 972, 752 (cm-1). MS (EI): m/z(%) = 93.1 (43),121.1
(48), 358.0 (100), 498.0 (77, M+). HRMS (EI) (m/z) [C21H22BrO7P]+: Calcd.
496.0287, Found.496.0278.
3-(Diethyl phosphoryl)-4-phenyl-1H-thieno[2, 3-c]pyran-1-one (3la):
1
colorless oil (127.4mg, 70% yield). H NMR (400 MHz, CDCl3)  = 7.79
(d, J = 5.1 Hz, 1H), 7.44 (dd, J = 18.4, 7.1 Hz, 5H), 6.85 (d, J = 5.1 Hz,
1H), 4.13 – 4.04 (m, 2H), 4.02 – 3.92 (m, 2H), 1.19 (t, J = 7.0 Hz, 6H)
(ppm).13C NMR (100 MHz, CDCl3)  = 156.9 (JC-P = 4.0 Hz), 147.7, 147.5,
147.4, 145.1, 136.6, 132.8, 129.9, 129.0, 128.6, 126.3, 126.1, 125.9 (JC-P
= 8.0 Hz), 125.8, 63.7, 63.6, 16.24, 16.18 (ppm). 31P NMR (160 MHz,
CDCl3)  = 3.89 (ppm). IR (in KBr) v = 3456, 3061, 2983, 2929, 2868,
1732, 1714, 1492, 1444, 1425, 1392, 1259, 1224, 1168, 1147, 1093,
1045, 1024, 989, 968, 794, 750, 702 (cm-1). MS (EI): m/z(%) = 93.0 (64),
121.1 (100), 171.0 (45), 199.0 (38), 227.0 (63), 364.0 (34, M+). HRMS
(ESI) (m/z) [C17H17O5PS+H+]: Calcd. 365.0607, Found.365.0608.
3-(Diethyl phosphoryl)-4-(3, 4-dioxolophenyl)-1H-2-benzopyran-1-
one (3af): bright-yellow oil (160.8 mg, 80% yield). 1H NMR (400 MHz,
CDCl3)  = 8.36 (d, J = 7.7 Hz, 1H), 7.64 (dd, J = 22.5, 7.7 Hz, 2H), 7.17
(d, J = 7.9 Hz, 1H), 6.91 (d, J = 7.8 Hz, 1H), 6.88 – 6.69 (m, 2H), 6.03 (d,
J = 9.5 Hz, 2H), 4.18 – 3.97 (m, 4H), 1.27 (m, 6H) (ppm). 13C NMR (100
MHz, CDCl3)  = 160.8 (JC-P = 9.0 Hz), 148.2, 147.8, 145.7, 143.4, 137.5,
137.3, 135.0, 130.2, 129.8, 127.8, 127.6, 126.7, 125.5 (JC-P = 2.7 Hz),
124.5, 122.0, 111.0, 108.5, 101.5 , 63.7, 63.6, 63.53, 63.46, 16.4, 16.34,
16.27 (ppm). 31P NMR (160 MHz, CDCl3)  = 3.95 (ppm). IR(in KBr) v =
2983, 2906, 2929, 1739, 1602, 1489, 1438, 1394, 1236, 1166, 1128,
1022, 979, 881, 752 (cm-1). MS (EI): m/z(%) = 93.1 (56), 121.1 (100),
151.1 (49), 237.1 (30), 264.1 (72),402.1 (42, M+). HRMS (EI) (m/z)
[C20H19O7P]+: Calcd. 402.0868, Found.402.0877.
3-(Diethyl phosphoryl)-4-(4-methylphenyl)-1H-2-benzopyran-1-one
1
(3ab): colorless oil (150.5mg, 81% yield). H NMR (400 MHz, CDCl3) 
= 8.32 (d, J = 7.5 Hz, 1H), 7.58 (m , 2H), 7.30 – 7.18 (m, 4H), 7.06 (d, J =
7.9 Hz, 1H), 4.10 – 4.00 (m, 2H), 3.99 – 3.89 (m, 2H), 2.38 (s, 3H), 1.18
(t, J = 7.0 Hz, 6H) (ppm). 13C NMR (100 MHz, CDCl3)  = 160.8 (JC-P
=
9.0 Hz), 138.7, 137.4 (JC-P = 14.7 Hz), 134.84, 130.5 (JC-P = 1.3 Hz),
130.1, 129.6, 129.2, 129.1, 128.1, 127.9, 126.7, 122.0, 63.5, 63.4, 21.4,
16.3,16.2 (ppm). 31P NMR (160 MHz, CDCl3)  = 4.09 (ppm). IR (in KBr)
v = 3558, 3462, 3448, 2983, 2929, 2870, 1739, 1645, 1514, 1454, 1394,
1259, 1166, 1128, 1045, 1022, 975, 752 (cm-1). MS (EI): m/z(%) = 93.1
(46), 121.1 (100), 179.1 (41), 235.2 (35), 372.2 (47, M+). HRMS (EI) (m/z)
[C20H21O5P]+: Calcd. 372.1127, Found.372.1126.
3-(Diethyl
phosphoryl)-4-(4-chlorophenyl)-1H-2-benzopyran-1-one
(3ag): colorless oil (166.6 mg, 85% yield). 1H NMR (400 MHz, CDCl3)  =
8.37 (d, J = 7.6 Hz, 1H), 7.69 – 7.59 (m, 2H), 7.47 (d, J = 8.3 Hz, 2H),
7.31 (d, J = 8.3 Hz, 2H), 7.04 (d, J = 7.9 Hz, 1H), 4.16 – 4.08 (m, 2H),
4.06 – 3.97 (m, 2H), 1.24 (t, J = 7.1 Hz, 6H) (ppm). 13C NMR (100 MHz,
CDCl3)  = 160.5 ( JC-P = 9.0 Hz), 145.8, 137.0 (JC-P = 14.5 Hz), 135.0,
132.1 (JC-P = 1.4 Hz), 130.4, 129.9, 128.8, 126.8 (JC-P = 20.0 Hz ), 126.4
(JC-P = 1.3Hz) , 122.0, 63.7, 63.6, 16.30, 16.24 (ppm). 31P NMR (160
MHz, CDCl3)  = 6.61 (ppm). IR(in KBr) v = 2983, 2906, 2868, 1743,
1597, 1489, 1452, 1394, 1263, 1166, 1130, 1091, 1047, 1020, 975, 873,
3-(Diethyl
phosphoryl)-4-(3-methyphenyl)-1H-2-benzopyran-1-one
(3ac): colorless oil (145.1mg, 78% yield). 1H NMR (400 MHz, CDCl3)  =
8.35 (d, J = 7.7 Hz, 1H), 7.60 (dd, J = 15.5, 7.6 Hz, 2H), 7.34 (d, J = 7.5
Hz, 1H), 7.24 (s, 1H), 7.15 (d, J = 7.4 Hz, 2H), 7.06 (d, J = 7.9 Hz, 1H),
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European Journal of Organic Chemistry
10.1002/ejoc.201601330
FULL PAPER
752, 696 (cm-1). MS (EI): m/z(%) = 93.1 (43), 121.1 (100), 163.1 (34),
199.1 (32), 392.2 (24, M+). HRMS (EI) (m/z) [C19H18ClO5P]+: Calcd.
392.0580, Found.392.0571.
2H), 1.60 – 1.46 (m, 4H), 1.34 –1.27 (m, 4H), 0.87 (t, J = 7.4 Hz, 6H)
(ppm). 13C NMR (100 MHz, CDCl3)  = 160.7 (JC-P = 9.0 Hz), 145.8,
143.4, 137.3, 137.2, 134.9, 132.3 (JC-P = 2.7Hz), 130.7 (JC-P =1.3 Hz),
130.1, 129.7, 128.8, 128.5, 127.9, 126.7 (JC-P = 1.3 Hz), 122.0, 67.2, 67.1,
32.4, 32.3, 18.7, 13.6 (ppm). 31P NMR (160 MHz, CDCl3)  = 4.19 (ppm).
IR (in KBr) v = 2960, 2933, 2872, 1741, 1600, 1456, 1313, 1261, 1128,
1022, 759, 698, 584, 524 (cm-1). MS (EI): m/z(%) = 121.1 (54), 165.1 (92),
210.1 (53), 221.1 (82), 238.1 (73), 303.0 (46), 414.1 (36, M+). HRMS
(ESI) (m/z) [C23H27O5P+H+]: Calcd.415.1669, Found. 415.1672.
3-(Diethyl phosphoryl)-4-naphthyl-1H-2-benzopyran-1-one (3ah):
bright-yellow oil (150.8mg, 75% yield). 1H NMR (400 MHz, CDCl3)  =
8.44 – 8.38 (m, 1H), 8.08 (d, J = 7.7 Hz, 1H), 7.99 – 7.85 (m, 4H), 7.64 –
7.62 (m, 1H), 7.56 – 7.53 (m, 1H), 7.49 – 7.39 (m, 2H), 7.08 (dd, J = 5.8,
3.3 Hz, 1H), 4.13 – 3.78 (m, 4H), 1.18 (t, J = 7.1 Hz, 3H), 1.09 (t, J = 7.1
Hz, 3H) (ppm). 13C NMR (100 MHz, CDCl3)  = 160.8 (JC-P = 9.0 Hz),
145.9, 143.6, 137.4, 137.3, 135.0, 133.4, 133.3, 133.2, 130.2 (JC-P = 2.0
Hz), 129.8, 129.6 (JC-P = 2.0 Hz), 128.5, 128.3, 128.2, 128.1, 128.0,
127.8, 126.9, 126.8 (JC-P = 8.0 Hz), 122.1 (JC-P = 1.0 Hz) , 63.8, 63.7,
63.54, 63.47, 16.3, 16.21, 16.18, 16.1 (ppm). 31P NMR (160 MHz, CDCl3)
 = 4.17 (ppm). IR (in KBr) v = 3739, 2981, 2931, 2866, 1739, 1512,
1458, 1265, 1170, 1126, 1022, 972, 806, 754 (cm-1). MS (EI): m/z(%) =
93.1 (46), 121.1 (100), 215.1 (96), 270.1 (73), 408.1 (95, M+). HRMS (EI)
(m/z) [C23H21O5P]+: Calcd. 408.1127, Found.408.1111.
4-Phenyl-1-oxo-1H-2-benzopyran-3-carboxylic ethyl ester (6aa):
yellow solid (117.6 mg, 80% yield). m.p.: 100 – 102 oC. 1H NMR (400
MHz, CDCl3)  = 8.36 (d, J = 7.9 Hz, 1H), 7.77 (m, 2H), 7.65 (d, J = 7.1
Hz, 2H), 7.58 (t, J = 7.4 Hz, 1H), 7.46 (d, J = 6.8 Hz, 3H), 4.20 (q, J = 7.1
Hz, 2H), 1.04 (t, J = 7.1 Hz, 3H) (ppm). 13C NMR (100 MHz, CDCl3)  =
166.5, 161.2, 155.5, 135.4, 134.8, 132.7, 130.7, 130.0, 128.9, 128.6,
128.3, 124.3, 119.9, 111.1, 62.1, 13.7 (ppm). IR (in KBr) v = 3062, 2981,
2933, 2902, 1747, 1722, 1624, 1685, 1448, 1371, 1342, 1315, 1241,
1232, 1124, 1091, 1053, 1018, 754, 694 (cm-1). MS (EI): m/z(%) = 77.0
(36), 92.0 (25), 105.0 (100), 238.0 (34), 294.0 (83, M+). HRMS (ESI) (m/z)
[C18H14O4+H+]: Calcd.295.0965, Found. 295.0973.
3-(Diethyl phosphoryl)-4-thiophenyl-1H-2-benzopyran-1-one (3ai):
bright-yellow oil (108.5 mg, 72% yield). 1H NMR (400 MHz, CDCl3)  =
8.36 (d, J = 7.9 Hz, 1H), 7.70 (d, J = 7.8 Hz, 1H), 7.63 (d, J = 7.6 Hz, 1H),
7.54 (d, J = 5.0 Hz, 1H), 7.31 (d, J = 8.0 Hz, 1H), 7.19 (dd, J = 12.2, 3.9
Hz, 2H), 4.25 – 4.05 (m, 4H), 1.29 (t, J = 7.0 Hz, 6H) (ppm). 13C NMR
(100 MHz, CDCl3)  = 160.4 (JC-P = 9.0 Hz), 137.5, 135.2, 131.8, 130.9
(JC-P = 1.2 Hz), 130.4, 129.7, 128.2, 127.3, 126.5 (JC-P = 1.4 Hz) ,121.6
(JC-P = 1.2 Hz), 121.3, 63.83, 63.77, 16.4, 16.3 (ppm). 31P NMR (160
MHz, CDCl3)  = 3.49 (ppm). IR (in KBr) v = 2955, 2924, 2852, 1743,
1461, 1377, 1261, 1020, 800 (cm-1). MS (EI): m/z(%) = 93.1 (58), 121.1
(100), 171.1 (38), 199.1 (39), 227.0 (43), 364.0 (52, M+). HRMS (EI) (m/z)
[C17H17O5PS]+: Calcd.364.0534, Found. 364.0538.
4-Phenyl-6-methyl-1-oxo-1H-2-benzopyran-3-carboxylic ethyl ester
(6ba): yellow oil (126.3 mg, 82% yield). 1H NMR (400 MHz, CDCl3)  =
8.25 (d, J = 8.1 Hz, 1H), 7.64 (d, J = 7.2 Hz, 2H), 7.52 (s, 1H), 7.46 (d, J
= 6.8 Hz, 3H), 7.39 (d, J = 8.1 Hz, 1H), 4.20 (q, J = 7.1 Hz, 2H), 2.51 (s,
3H), 1.03 (t, J = 7.1 Hz, 3H) (ppm). 13C NMR (100 MHz, CDCl3)  = 166.6,
161.3, 155.6, 146.7, 134.8, 132.9, 130.6, 130.3, 130.0, 128.6, 128.3,
124.2, 117.5, 111.0, 62.0, 22.4, 13.7 (ppm). IR (in KBr) v = 3057, 2962,
2937, 2862, 1726, 1496, 1446, 1375, 1257, 1228, 1211, 1180, 1151,
1074, 1033, 800, 754 (cm-1). MS (EI): m/z(%) = 77.0 (40) , 105.0 (100),
252.0 (37), 308.1 (70, M+). HRMS (ESI) (m/z) [C19H16O4+H+]:
Calcd.309.1121, Found.309.1128.
3-(Dimethyl phosphoryl)-4-phenyl-1H-2-benzopyran-1-one (3aj):
white solid (118.8mg, 72% yield). m.p.: 104 – 106 oC. 1H NMR (400 MHz,
CDCl3)  = 8.39 (d, J = 7.5 Hz, 1H), 7.70 – 7.59 (m, 2H), 7.51 (d, J = 7.4
Hz, 3H), 7.41 – 7.35 (m, 2H), 7.07 (d, J = 7.8 Hz, 1H), 3.63 (d, J = 11.3
Hz, 6H) (ppm). 13C NMR (100 MHz, CDCl3)  = 160.7 (JC-P = 8.0 Hz),
145.2, 142.9, 137.2, 137.1, 135.0, 132.1 (JC-P = 2.7 Hz), 130.6 (JC-P = 1.5
Hz), 130.4, 129.8, 129.0, 128.6, 128.4, 128.2, 126.8 (JC-P = 1.5 Hz),
122.1 (JC-P = 1.3 Hz) , 53.9, 53.8 (ppm). 31P NMR (160 MHz, CDCl3)  =
6.61 (ppm). IR (in KBr) v = 2960, 1739, 1286, 1247, 1133, 1052, 1025,
891, 766, 565, 519 (cm-1). MS (EI): m/z(%) = 84.0 (80), 93.1 (100), 165.1
(57), 330.1 (40, M+). HRMS (EI) (m/z) [C17H15O5P]+: Calcd.330.0657,
Found.330.0641.
4-Phenyl-6-methoxyl-1-oxo-1H-2-benzopyran-3-carboxylic
ethyl
ester (6ea): yellow solid (134.5mg, 83% yield). m.p.: 138 – 140 oC. 1H
NMR (400 MHz, CDCl3)  = 8.27 (d, J = 8.8 Hz, 1H), 7.62 (d, J = 7.0 Hz,
2H), 7.45 (d, J = 7.1 Hz, 3H), 7.17 (s, 1H), 7.09 (d, J = 8.8 Hz, 1H), 4.17
(q, J = 7.1 Hz, 2H), 3.92 (s, 3H), 1.00 (t, J = 7.1 Hz, 3H) (ppm). 13C NMR
(100 MHz, CDCl3)  = 166.6, 165.2, 161.0, 156.6, 137.1, 132.9, 132.2,
130.6, 128.5, 128.3, 117.0, 112.9, 110.7, 106.9, 61.9, 55.9, 13.6 (ppm).
IR (in KBr) v = 3059, 2964, 2927, 2850, 1728, 1606, 1568, 1487, 1452,
1369, 1325, 1263, 1215, 1178, 1093, 1039, 800, 758 (cm-1). MS (EI):
m/z(%) = 77.0 (39) , 105.0 (100), 268.0 (58), 324.0 (98, M+). HRMS (ESI)
(m/z) [C19H16O5+H+]: Calcd.325.1071, Found.325.1072.
3-(Diisopropyl phosphoryl)-4-phenyl- 1H-2-benzopyran-1-one (3ak):
white solid (154.4mg, 80% yield). m.p.: 110 – 112 oC. 1H NMR (400 MHz,
CDCl3)  = 8.38 (d, J = 7.7 Hz, 1H), 7.62 (m, 2H), 7.47 (d, J = 5.0 Hz, 3H),
7.39 – 7.31 (m, 2H), 7.07 (d, J = 7.8 Hz, 1H), 4.71– 4.64 (m, 2H), 1.28 (d,
J = 6.2 Hz, 6H), 1.21 (d, J = 6.2 Hz, 6H) (ppm). 13C NMR (100 MHz,
CDCl3)  = 160.9 (JC-P = 11.0 Hz), 143.9, 137.6, 137.5, 134.9, 132.5 (JC-P
= 2.5 Hz ), 130.9 (JC-P = 1.4 Hz), 129.7, 128.8, 128.5, 126.7 (JC-P = 1.2
4-Phenyl-1-oxo-1H- thieno[2, 3-c]pyran-3-carboxylic ethyl ester (6la):
yellow oli (120.1 mg, 80% yield). H NMR (400 MHz, CDCl3)  = 7.91 (d,
1
J = 5.1 Hz, 1H), 7.59 (dd, J = 9.8, 6.5 Hz, 3H), 7.47 (dd, J = 11.9, 7.0 Hz,
3H), 4.17 (q, J = 7.1 Hz, 2H), 1.02 (t, J = 7.1 Hz, 3H) (ppm). 13C NMR
(100 MHz, CDCl3)  = 165.8, 160.1, 157.1, 145.5, 137.3, 132.8, 131.8,
130.8, 128.8, 128.4, 125.4, 123.0, 109.1,61.8, 13.6 (ppm). IR (in KBr) v =
3086, 2962, 2936, 1737, 1712, 1524, 1416, 1364, 1244, 1223, 1180,
1066, 846, 807, 767, 687 (cm-1). MS (EI): m/z(%) = 77.1 (35) , 105.1
(100), 272.0 (17), 300.1 (46, M+). HRMS (ESI) (m/z) [C16H12O4S+H+]:
Calcd.301.0529, Found.301.0564.
Hz), 122.1 (JC-P = 1.2 Hz), 72.7, 72.6, 24.19, 24.15, 23.7, 23.6 (ppm). 31
P
NMR (160 MHz, CDCl3)  = 2.22 (ppm). IR (in KBr) v = 3460, 3442, 2981,
2933, 2981, 2873, 1739, 1643, 1514, 1454, 1381, 1259, 1172, 1105, 999,
891, 754 (cm-1). MS (EI): m/z(%) = 57.1 (57), 71.1 (50) , 165.1 (47),
210.1 (50), 238.0 (100), 386.0 (28, M+). HRMS (ESI) (m/z)
[C21H23O5P+H+]: Calcd.387.1356, Found.387.1358.
4-Phenyl-1-oxo-1H-2-benzopyran-3-carboxylic methyl ester (6ab):
yellow oli (114.8mg, 82% yield). 1H NMR (400 MHz, CDCl3)  = 8.36 (d, J
= 7.9 Hz, 1H), 7.79 (t, J = 7.6 Hz, 1H), 7.71 (d, J = 7.9 Hz, 1H), 7.64 (d, J
= 7.5 Hz, 2H), 7.58 (t, J = 7.5 Hz, 1H), 7.47 (d, J = 6.2 Hz, 3H), 3.72 (s,
3H) (ppm). 13C NMR (100 MHz, CDCl3)  = 167.0, 161.2, 155.5, 135.4,
134.7, 132.6, 130.8, 130.0, 129.0, 128.7, 128.1, 124.3, 119.9, 110.7,
3-(Dibutyl
phosphoryl)-4-phenyl-1H-2-benzopyran-1-one
(3al):
colorless oil (129.6 mg, 79% yield). 1H NMR (400 MHz, CDCl3)  = 8.37
(d, J = 7.7 Hz, 1H), 7.62 (m, 2H), 7.47 (d, J = 6.0 Hz, 3H), 7.36 (d, J = 5.4
Hz, 2H), 7.06 (d, J = 7.9 Hz, 1H), 4.05 – 3.98 (m, 2H), 3.92 – 3.80 (m,
This article is protected by copyright. All rights reserved

European Journal of Organic Chemistry
10.1002/ejoc.201601330
FULL PAPER
52.80 (ppm). IR (in KBr) v = 2958, 2924, 2854, 1735, 1602, 1444, 1263,
1132, 1083, 1026, 800, 756 (cm-1). MS (EI): m/z(%) = 165.0 (90), 193
(60), 221.0 (100),280.0 (97, M+). HRMS (ESI) (m/z) [C17H12O4+H+]:
Calcd.281.0808, Found. 281.0813.
118.4, 114.1, 63.1, 46.0 (ppm). IR (in KBr) v = 2956, 2920, 2850, 1741,
1483, 1417, 1255, 1228, 1068, 1024, 839, 765 (cm-1). MS (EI): m/z(%) =
111.1 (47), 130.1 (57), 139.0 (100), 282.0 (90) , 297.1 (97), 341.1 (50,
M+). HRMS (ESI) (m/z) [C18H12NO4Cl+H+]: Calcd. 342.0528,
Found.342.0538.
4-(4-Methylphenyl)-1-oxo-1H-2-benzopyran-3-carboxylic
methyl
ester (6ac): white solid (126.5mg, 86% yield). m.p.: 116 – 118 oC. 1H
NMR (400 MHz, CDCl3)  = 8.34 (d, J = 7.9 Hz, 1H), 7.77 (t, J = 7.7 Hz,
1H), 7.68 (d, J = 8.1 Hz, 1H), 7.54 (dd, J = 13.0, 7.6 Hz, 3H), 7.27 – 7.23
(m, 2H), 3.73 (s, 3H), 2.40 (s, 3H) (ppm). 13C NMR (100MHz, CDCl3)  =
167.2, 161.3, 155.5, 141.2, 135.4, 134.9, 130.0, 129.7, 129.43, 128.8,
128.0, 124.2, 119.8, 110.28, 52.8, 21.6 (ppm). IR (in KBr) v = 2958, 2868,
1726, 1618, 1560, 1483, 1435, 1346, 1315, 1257, 1089, 1020, 754 (cm-1).
MS (EI): m/z(%) = 91.0 (35), 119.0 (100), 266.0 (44), 294.0 (78, M+).
HRMS (ESI) (m/z) [C18H14O4+H+]: Calcd.295.0965, Found. 295.0961.
3-(2-Oxo-3-oxazolidinyl)-4-phenyl-6-methyl-1H-2-benzopyran-1-one
(7ba): white solid (128.4mg, 80% yield). m.p.: 250 – 252 oC. 1H NMR
(400 MHz, CDCl3)  = 8.24 (d, J = 8.1 Hz, 1H), 7.72 – 7.67 (m, 2H), 7.49
(d, J = 4.6 Hz, 3H), 7.40 (d, J = 8.0 Hz, 1H), 7.22 (s, 1H), 4.55 (dd, J =
15.3, 8.9 Hz, 1H), 4.34 – 4.28 (m, 1H), 3.75 (dd, J = 16.8, 8.5 Hz, 1H),
3.36 (dd, J = 15.3, 8.7 Hz, 1H), 2.52 (s, 3H) (ppm). 13C NMR (100 MHz,
CDCl3)  = 161.0, 158.0, 154.7, 147.0, 135.3, 130.9, 130.7, 130.6, 129.0,
128.1, 121.6, 118.5, 113.7, 63.1, 45.9, 22.5 (ppm). IR (in KBr) v = 2956,
2920, 2854, 1741, 1614, 1485, 1417, 1265, 1228, 1132, 1072, 1033, 765
(cm-1). MS (EI): m/z(%) = 77.1 (44), 105.1 (67), 141.1 (48), 262.1 (100),
277.1 (88), 321.1 (42, M+). HRMS (ESI) (m/z) [C19H15NO4+H+]: Calcd.
322.1074, Found.322.1086.
3-(2-Oxo-3-oxazolidinyl)-4-phenyl-1H-2-benzopyran-1-one
(7aa):
yellow solid (127.4mg, 83% yield). m.p.: 218 – 220 oC. 1H NMR (400
MHz, CDCl3)  = 8.35 (d, J = 6.6 Hz, 1H), 7.76 (d, J = 45.9 Hz, 3H), 7.54
(d, J = 37.7 Hz, 5H), 4.54 (d, J = 5.8 Hz, 1H), 4.32 (d, J = 7.4 Hz, 1H),
3.76 (d, J = 7.6 Hz, 1H), 3.38 (d, J = 5.8 Hz, 1H) (ppm). 13C NMR (100
MHz, CDCl3)  = 160.9, 157.9, 154.7, 135.6, 135.2, 130.9, 130.8, 130.7,
129.2, 129.03, 128.1, 121.7, 120.8, 113.9, 63.1, 45.9 (ppm). IR (in KBr) v
= 2958, 2920, 2927, 2850, 1743, 1633, 1602, 1481, 1419, 1309, 1257,
1228, 1128, 1072, 1024, 759, 694 (cm-1). MS (EI): m/z(%) = 77.1 (74),
105.1 (100), 130.1 (34), 165.1 (36), 248.1 (65), 263.1 (47), 307.1 (12, M+).
HRMS (EI) (m/z) [C18H13NO4]+: Calcd. 307.0845, Found.307.0836.
3-(2-Oxo-3-oxazolidinyl)-4-phenyl -1H- thieno [2, 3-c] pyran -1-one
(7la): yellow solid (129.9mg, 83% yield). m.p.: 206 – 208 oC. 1H NMR
(400 MHz, CDCl3)  = 7.90 (d, J = 5.1 Hz, 1H), 7.77 – 7.68 (m, 2H), 7.49
(d, J = 4.8 Hz, 3H), 7.19 (d, J = 5.1 Hz, 1H), 4.51 (dd, J = 14.6, 8.6 Hz,
1H), 4.32 (q, J = 8.4 Hz, 1H), 3.74 (q, J = 8.5 Hz, 1H), 3.42 (dd, J = 14.6,
8.4 Hz, 1H) (ppm). 13C NMR (100 MHz, CDCl3)  = 157.5, 156.9, 155.8,
146.4, 137.9, 131.0, 130.5, 129.1, 128.1, 123.6, 122.6, 113.4, 63.2, 46.0
(ppm). IR (in KBr) v = 3084, 2960, 2922, 2856, 1730, 1610, 1487, 1436,
1257, 1083, 1031, 1018, 798, 765, 694 (cm-1). MS (EI): m/z(%) = 77.1
(68), 105.1 (100), 171.1 (48), 254.1 (66), 269.1 (72), 313.1 (97, M+).
HRMS (ESI) (m/z) [C16H11NO4S+H+]: Calcd. 314.0482, Found.314.0488.
3-(2-Oxo-3-oxazolidinyl)-4-(4-methylphenyl)-1H-2-benzopyran-1-one
o
(7ab): yellow solid (139.7mg, 87% yield). m.p.: 220 – 222 C. 1H NMR
(400 MHz, CDCl3)  = 8.35 (d, J = 7.9 Hz, 1H), 7.81 (t, J = 7.6 Hz, 1H),
7.59 (dd, J = 15.8, 7.8 Hz, 3H), 7.46 (d, J = 8.0 Hz, 1H), 7.29 (d, J = 7.9
Hz, 2H), 4.55 (dd, J = 15.4, 8.9 Hz, 1H), 4.34 (dd, J = 16.8, 8.5 Hz, 1H),
3.75 (dd, J = 16.7, 8.5 Hz, 1H), 3.41 (dd, J = 15.3, 8.8 Hz, 1H), 2.42 (s,
3H) (ppm). 13C NMR (100 MHz, CDCl3)  = 161.0, 157.9, 154.8, 141.3,
135.5, 135.4, 130.6, 129.7, 129.0, 128.0, 121.6, 120.8, 113.3, 63.1, 45.8,
21.7 (ppm). IR (in KBr) v = 2960, 2920, 1743, 1627, 1602, 1481, 1417,
1305, 1253, 1228, 1126, 1068, 1026, 767 (cm-1). MS (EI): m/z(%) = 91.1
(51), 119.1 (95), 234.1 (42), 262.1 (100), 277.1 (71), 321.1 (70, M+).
HRMS (ESI) (m/z) [C19H15NO4+H+]: Calcd. 322.1074, Found.322.1081.
Acknowledgements
The authors are grateful for the financial support from the
National Natural Science Foundation of China (NSFC) (grant
number 21072052), the National Basic Research Program of
China (grant number 2009CB421601), and the Hunan Provincial
Science and Technology Department Program (grant number
2011WK4007, 06FJ4115) and The Fundamental Research
Funds for the Central Universities, Hunan University (grant
number 531107040840).
3-(2-Oxo-3-oxazolidinyl)-4-(3-methylphenyl-1H-2-benzopyran-1-one
(7ac): white solid (141.3mg, 88% yield). m.p.: 170 – 172 oC. 1H NMR
(400 MHz, CDCl3)  = 8.35 (d, J = 7.9 Hz, 1H), 7.82 (t, J = 7.6 Hz, 1H),
7.58 (t, J = 7.6 Hz, 1H), 7.54 – 7.45 (m, 3H), 7.37 (t, J = 7.6 Hz, 1H), 7.31
(d, J = 7.5 Hz, 1H), 4.54 (dd, J = 15.4, 8.8 Hz, 1H), 4.31 (dd, J = 16.9, 8.5
Hz, 1H), 3.75 (dd, J = 16.7, 8.4 Hz, 1H), 3.40 (dd, J = 15.3, 8.7 Hz, 1H),
2.41 (s, 3H) (ppm). 13C NMR (100 MHz, CDCl3)  = 161.0, 157.9, 154.8,
138.9, 135.5, 135.3, 131.7, 130.8, 130.6, 129.1, 128.9, 128.7, 125.1,
121.7, 120.8, 113.7, 63.1, 45.9, 21.6 (ppm). IR (in KBr) v = 2960, 2920 ,
2856, 1747, 1631, 1602, 1479, 1417, 1259, 1226, 1076, 1026, 758 (cm-1).
MS (EI): m/z(%) = 91.1 (27), 119.1 (52), 262.1 (100), 277.1 (56), 321.1
(53, M+). HRMS (ESI) (m/z) [C19H15NO4+H+]: Calcd. 322.1074,
Found.322.1087.
Keywords: Rhodium catalysis • regioselective • oxygen • 3-
hetero isocoumarins • annulation reaction
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3-(2-Oxo-3-oxazolidinyl)-4-(4-chlorophenyl)-1H-2-benzopyran-1-one
(7ad): white solid (143.3mg, 84% yield). m.p.: 256 – 258 oC. 1H NMR
(400 MHz, CDCl3)  = 8.36 (d, J = 7.9 Hz, 1H), 7.83 (t, J = 7.6 Hz, 1H),
7.67 (d, J = 8.2 Hz, 2H), 7.61 (t, J = 7.6 Hz, 1H), 7.46 (t, J = 8.6 Hz, 3H),
4.58 (dd, J = 15.3, 9.0 Hz, 1H), 4.38 (dd, J = 16.9, 8.7 Hz, 1H), 3.79 (dd,
J = 16.8, 8.5 Hz, 1H), 3.41 (dd, J = 15.2, 8.8 Hz, 1H) (ppm). 13C NMR
(100 MHz, CDCl3)  = 160.6, 157.9, 153.6, 148.7, 137.2, 136.0, 135.7,
135.0, 132.6, 130.8, 129.5, 129.4, 129.4, 129.3, 125.7, 121.7, 120.9,
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765-769.
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This article is protected by copyright. All rights reserved

European Journal of Organic Chemistry
10.1002/ejoc.201601330
FULL PAPER
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This article is protected by copyright. All rights reserved

European Journal of Organic Chemistry
10.1002/ejoc.201601330
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Transition metal-catalysis
Lijuan Song, Jing Xiao, Wanrong Dong*,
Zhihong Peng* and Delie An*
Page No. – Page No.
Rh(III)-Catalyzed Regioselective
Preparation of 3-Hetero Isocoumarins
from Aryl Carboxylic Acid and
Alkynes
Various novel 3-hetero substituted isocoumarins were successfully prepared under
O2 atmosphere with assistance of a rhodium catalyst in regioselective manner. And
the high regioselectivity was propably attributed for the difference of the electron-
density on the alkynyl carbons.
State Key Laboratory of Chemo/Biosensing and Chemometrics, Co
Chemistry and Chemical Engineering
Hunan University
Changsha, 410082, P. R. of China.
Tel. (Fax):+86 731 88821380
E-mail: wanrongdong@hnu.edu.cn; pzh7251@hnu.edu.cn;
deliean@hnu.edu.cn
Supporting information for this article is given via a link at the end o
document.((Please delete this text if not appropriate))
This article is protected by copyright. All rights reserved