Gold-catalyzed hydroarylation of aryl alkynylphosphonates for the synthesis of phosphacoumarins

Article abstract of DOI:10.1002/adsc.201300545

Intramolecular hydroarylation using aryl alkynylphosphonates proceeds smoothly with a gold/ silver catalyst in the presence of trifluoromethanesulfonic acid (TfOH) in the 6-endo mode, thus affording a unique synthetic method for phosphacoumarins having various functional groups, which could be a privileged structure and prevalent scaffold in phosphorus heterocycles.

Full text of DOI:10.1002/adsc.201300545

FULL PAPERS
DOI: 10.1002/adsc.201300545
Gold-Catalyzed Hydroarylation of Aryl Alkynylphosphonates for
the Synthesis of Phosphacoumarins
Cheol-Eui Kim,a Taekyu Ryu,a Sanghyuck Kim,a Kooyeon Lee,b Chang-Hee Lee,a
and Phil Ho Leea,*
a
Department of Chemistry, Kangwon National University, Chuncheon 200-701, Republic of Korea
Fax : (+82)-33-253-7582; e-mail: phlee@kangwon.ac.kr
Department of Bio-Health Technology, Kangwon National University, Chuncheon 200-701, Republic of Korea
b
Received: June 20, 2013; Published online: October 9, 2013
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201300545.
Abstract: Intramolecular hydroarylation using aryl a privileged structure and prevalent scaffold in phos-
alkynylphosphonates proceeds smoothly with a gold/ phorus heterocycles.
silver catalyst in the presence of trifluoromethanesul-
fonic acid (TfOH) in the 6-endo mode, thus affording Keywords: cyclization; gold; homogenous catalysis;
a unique synthetic method for phosphacoumarins hydroarylation; phosphacoumarins; phosphorus het-
having various functional groups, which could be erocycles
Introduction
tion of salicylaldehyde with triethyl phosphonoacetate
[Eq. (1)].[4c,5] Fuꢀs group has developed a convenient
Organophosphorus compounds have received con- synthetic method for 4-O-acylated, phosphorylated,
tinuing interest due to their frequency in living sys- sulfonylated and alkylated phosphacoumarins through
tems and their potential to function as novel biologi- intramolecular condensation of 2-methoxycarbonyl-
cally active compounds.[1] Therefore, the development benzylphosphonate [Eq. (2)].[4d] Mironov et al. report-
of new synthetic methods for heterocyclic compounds ed the reaction of P,P,P-trihalobenzo-1,3,2-dioxa-
bearing phosphorus atom is crucial.[2] Since the phospholes with aryl- and alkylacetylenes to produce
carbon and their analogous phosphorus compounds phosphacoumarins [Eq. (3)].[6] They have also synthe-
have a conspicuous resemblance in regard to reactivi- sized phosphacoumarins from hexacoordinated phos-
ty and biological activity,[3] we foresee that the phos- phorus derivatives and alkynes [Eq. (4)].[7]
phacoumarins,[4] which may be recognized as phos-
Recently, the hydroarylation of alkynes catalyzed
phorus-containing analogues of coumarin, would have by transition metals has appeared as an efficient
pharmacological activities similar to those described method for the synthesis of functionalized carbocycles
for coumarins. As a consequence, we were attracted and heterocycles.[8] Since Fujiwara et al. reported the
in expanding an efficient procedure for the synthesis transition metal-catalyzed intramolecular hydroaryla-
of a number of phosphacoumarins with the purpose tion of alkynes,[8h] a variety of transition metal cata-
of making focused chemical libraries useful for chemi- lysts has been developed for the transformation.[8] Al-
cal biology research and drug discovery.
though research efforts have been concentrated on
In general, the approach to novel phosphacoumarin the development of catalysts and ligands, the scope
scaffolds can be realized either by functionalization of and types of substrates for the hydroarylation have re-
a preformed phosphacoumarin nucleus[4b] or by de ceived relatively little attention. As a consequence,
novo synthesis from appropriate starting materials.[4c–f] the development of new substrates in the hydroaryla-
While the former method usually requires chemose- tion process is very important for the synthesis of
lective transformation of functional groups already in- cyclic compounds. To date, a number of substrates
stalled, the latter one needs a synthetic methodology bearing amide, ester, ether, N-tosyl, malonate and
capable of directly constructing the phosphacoumarin aryl group as linkers between aromatic ring and mul-
nucleus with the suitable substitution pattern already tiple bond have been used in the hydroarylation reac-
introduced. Chen and Rodiosꢀs groups have reported tions. However, as far as we are aware, the use of al-
the preparation of phosphacoumarins by condensa-
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Results and Discussion
To examine the possibility of this process, we started
our study using diphenyl hexynylphosphonate 1a and
a range of gold catalysts along with silver salts and
protic acids were explored (Table 1). AuCl3 and AuCl
in the presence of AgOTf failed to catalyze the hy-
droarylation and the starting 1a was recovered (en-
tries 1 and 2). When 1a was treated with Ph3PAuCl
and AgNO3 (5 mol% each) in dichloroethane, the hy-
droarylation did not proceed (entry 4). In contrast to
AgNO3, the use of AgAsF6, AgSbF6, AgBF4, AgNTf2
and AgOTf produced b-keto phosphonate 3 through
hydration (entries 3 and 5–8). Unfortunately, the
more electrophilic gold catalyst derived from
(C6F5)3PAuCl and AgOTf (5 mol% each) gave 3
(entry 9). Next, a number of additives such as acetic
acid, trifluoroacetic acid and trifluoromethanesulfonic
acid (3 equiv.) were used in order to enhance the cat-
alytic activity of gold (entries 10–12).[9] Acetic acid
(AcOH) was completely ineffective and 3 was ob-
tained in 72% yield (entry 10). However, TFA afford-
ed the desired product 2a albeit in low yield (5%) to-
gether with 3 (18%) and recovered 1a (53%)
(entry 11). To our delight, a catalytic system of
kynylphosphonates has not been reported in the hy- Ph3PAuCl and AgOTf (5 mol% each) using TfOH as
droarylation reaction (Figure 1). an additive turned out to be the most effective, result-
On the basis of these results, we envisaged that it is ing in the consumption of 1a to provide selectively
of great interest to establish a novel synthetic route to phosphacoumarin 2a in 84% yield (isolated yield
phosphacoumarins
having diverse substituents 73%) through a selective 6-endo mode in DCE at
through hydroarylation of a new precursor without 808C for 17 h (entry 12). The control experiments
using preformed phosphacoumarins. Herein, we were performed without gold, silver and TfOH to
report an efficient synthetic method for phosphacou- prove their critical role in the hydroarylation (en-
marins through gold-catalyzed intramolecular hydro- tries 13-15). To check the feasibility of catalysis by
arylation of aryl alkynylphosphonates, thus phospha- a protic acid, we attempted the hydroarylation in the
coumarins bearing various substituents are produced presence of TfOH (3 equiv.), which produced 2a (3%)
relying on the substituent pattern of readily accessible and recovered 1a (50%) (entry 13). AgOTf alone was
aryl alkynylphosphonates (Scheme 1).
ineffective for the hydroarylation (entry 14). The re-
action performed in the presence of AgOTf and
TfOH gave a low product yield (entry 15). These re-
sults indicate that Ph3PAuCl, AgOTf and TfOH are
essential for the successful hydroarylation reaction.
With this optimized method in hand, we investigat-
ed a variety of ethyl phenyl alkynylphosphonates
(Scheme 2). Treatment of ethyl phenyl ethynyl-
phosphonate with Ph3PAuCl and AgOTf (5 mol%
each) in the presence of TfOH (3 equiv.) provided
the desired phosphacoumarin 2b in 72% yield at
258C. Ethyl phenyl hexynylphosphonate worked well
too. The phosphonate which was derived from phe-
nylacetylene afforded 2d in 82% yield. The phospho-
nates bearing 4-chloro and 4-bromo groups on the
phenyl ring underwent hydroarylation to afford 2e
and 2f with good yields. The tolerance of chloro and
bromo groups on phosphacoumarin is particularly val-
uable, as successive catalytic couplings are possible.
Next, hydroarylations of diphenyl alkynylphospho-
Figure 1. Substrates for intramolecular hydroarylation.
Scheme 1. Hydroarylation of aryl alkynylphosphonates.
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Gold-Catalyzed Hydroarylation of Aryl Alkynylphosphonates for the Synthesis of Phosphacoumarins
Table 1. Optimization of the hydroarylation reaction.[a]
Entry
Catalyst
Additive[b]
Temperature [oC]
Time [h]
Yield [%][c]
1a
2a
3
1
2
3
4
5
6
7
8
AuCl3/AgOTf[d]
AuCl/AgOTf
80
80
25
80
25
25
25
25
25
80
80
80
80
80
80
19
19
10
5
10
10
5
5
20
2
28
17
17
21
21
91
89
Ph3PAuCl/AgAsF6
Ph3PAuCl/AgNO3
Ph3PAuCl/AgSbF6
Ph3PAuCl/AgBF4
Ph3PAuCl/AgNTf2
Ph3PAuCl/AgOTf
83
88
82
85
85
85
84
72
18
5
9
A
10[e]
11[e]
12[e]
13[e]
14[e]
15[e]
Ph3PAuCl/AgOTf
Ph3PAuCl/AgOTf
Ph3PAuCl/AgOTf
AcOH
TFA
TfOH
TfOH
53
5
84 (73)[c]
3
50
78
77
AgOTf
AgOTf
4
TfOH
17
[a]
Reactions were carried out with Au and Ag (5 mol% each).
Additive (3 equiv.) was used.
Isolated yield.
[b]
[c]
[d]
[e]
Ag (15 mol%) was used.
Yields between entries 10 and 15 indicate NMR yield using dibromomethane as an internal standard.
nates were carried out. Diphenyl ethynylphosphonate phenyl ring turned out to be harmonious with the re-
was treated with gold catalyst to provide the desired action conditions. Under the optimized reaction con-
phosphacoumarin 2g in 80% yield at 258C. These re- ditions at room temperature, alkynyl phosphonates
sults indicate that the ethoxy and phenoxy groups at- bearing a 3,5-dimethylphenyl group were successfully
tached to phosphorus do not affect the efficiency of subjected to the hydroarylation, affording the desired
the present reaction. When diphenyl 5-chloropenty- phosphacoumarins 5d, 5e and 5f in excellent yields.
nylphosphonate was subjected to the standard condi- Interestingly, even when an electron-withdrawing tri-
tions, 4-(3-chloropropyl)phosphacoumarin 2h was iso- fluoromethyl group was located on the phenyl ring,
lated in 60% yield. Delightfully, hydroarylation using the reaction proceeded to provide 5g in 72% yield at
diphenyl phenylethynylphosphonate took place to room temperature. The phosphonate having a 3,5-di-
afford 2i in 94% yield. We were pleased to obtain methoxyphenyl group was effective for the hydroary-
phosphacoumarin 2j (68%) from the phosphonate de- lation, resulting in 5h in 76% yield. Of particular note
rived from 4-methoxyphenylacetylene, suggesting that was the use of phosphonates having 2- and 4-bromo-
electronic variation on the phenyl ring attached to al- phenyl groups: synthetically versatile 5i and 5j were
kynyl group did not much influence the cyclization ef- isolated in 60% and 71% yields, respectively, with an
ficiency.
intact aryl bromo group to afford potential for further
After that, we applied the gold-catalyzed hydroary- conversions.
lation to aryl alkynylphosphonates having substituents
However, when 4k was employed as the substrate,
on the phenyl ring attached to oxygen (Scheme 3). the hydroarylation reaction occurred unexpectedly via
When ethyl ortho- and para-tolyl hexynylphosphon- the 5-exo mode, producing 5k in 75% yield [Eq. (5)].
ACHTUNGTRENNUNGates were used as the substrate, the hydroarylation NOE experiments indicate that stereochemistry of 5k
took place smoothly to give rise to 5a and 5c in 72% is Z. When 4l was subjected to the standard condi-
and 71% yields, respectively. As expected, meta-sub- tions, the hydroarylative product 5l formed via the 5-
stituted substrates underwent the hydroarylation re- exo mode was isolated in 57% yield together with 5m
gioselectively at the sterically less hindered position, in 7% yield via the 6-endo mode [Eq. (6)].
producing 5b in 64% yield. Alkynylphosphonates pos-
A deuterium exchange reaction was carried out to
sessing two electron-donating methyl groups on the gain insights into the reaction mechanism. When 1i
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was treated with Ph3PAuCl and AgOTf (5 mol% anism has not been entirely proved at the present
each) using TfOD (3 equiv.), deuterium incorporation level, the gold/silver catalyst in the presence of TfOH
(88% D) was detected at the 3-position of the phos- activated the triple bond and an allene moiety as in-
phacoumarin [Eq. (7)]. However, quenching of the re- termediate might be involved in the hydroarylation.
action mixture obtained from 1a using TfOD The elucidation of the detailed reaction mechanism
(3 equiv.) gave rise to the deuterium incorporated and role of TfOH must await further study.
phosphacoumarin 2a-d (29% D) at the 3- as well as
exo-methylene carbons [Eq. (8)]. Although the mech-
Scheme 2. Hydroarylation of phenyl alkynylphosphonates.
Scheme 3. Hydroarylation of aryl alkynylphosphonates.
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Gold-Catalyzed Hydroarylation of Aryl Alkynylphosphonates for the Synthesis of Phosphacoumarins
tion mixture was then stirred at À788C for 1 h and 258C for
2 h or until completion; the reaction progress was followed
by TLC. When the reaction was complete, the solution was
quenched with saturated aquous NH4Cl. After the aqueous
layer had been separated and extracted with ether 3 times,
the organic fraction was dried with MgSO4, filtered and con-
centrated under reduced pressure. The resulting product was
then purified by flash column chromatography (EtOAc:hex-
ane).
Preparation of Aryl Ethynylphosphonates[10b]
A 0.5M solution of ethynylmagnesium bromide (1.2 equiv.)
in THF was added over 15 min into a solution of chloro-
phosphonate (1 equiv.) in THF (0.75M) at 08C. The mixture
was stirred for 1 h at 08C and then, the reaction was
quenched with saturated aqueous NH4Cl at 08C. After the
Conclusions
In summary, we have developed an intramolecular hy- aqueous layer had been separated and extracted with ether
3 times, the organic fraction was dried with MgSO4, filtered
and concentrated under reduced pressure. The resulting
product was then purified by flash column chromatography
(EtOAc:hexane).
droarylation
alkynylphosphon
lyst in the presence of TfOH in the selective 6-endo
mode, thus providing an effective and distinctive
method for phosphacoumarins having a range of func-
tional groups.
of
easily
accessible
aryl
ACHTUNGTRENNUNGates catalyzed by a gold/silver cata-
Diphenyl hex-1-ynylphosphonate (1a): yield: 105 mg
(66%); Rf =0.3 (EtOAc:hexane=1:5); colorless oil;
1H NMR (400 MHz, CDCl3): d=7.39–7.31 (m, 4H), 7.29–
7.26 (m, 3H), 7.26–7.24 (m, 1H), 7.24–7.17 (m, 2H), 2.29
(dt, J1 =4.64 Hz, J2 =7.02 Hz, 2H), 1.51–1.42 (m, 2H), 1.35–
1.24 (m, 2H), 0.85 (t, J=7.30 Hz, 3H); 13C NMR (100 MHz,
CDCl3): d=150.0 (d, J=7.37 Hz), 129.7, 125.5 (d, J=
1.11 Hz), 120.7 (d, J=4.96 Hz), 106.5 (d, J=55.4 Hz), 69.5
(d, J=322.04 Hz), 29.0 (d, J=2.22 Hz), 21.7, 18.9 (d, J=
4.4 Hz), 13.3; 31P NMR (121 MHz, CDCl3): d=À14.65; IR
(film): n=2959, 2206, 1590, 1488, 1284, 1186, 1024, 949,
Experimental Section
General
Ph3PAuCl and AgOTf were purchased from Alfa Chemical
Co. and were used as received. TfOH was purchased from
Aldrich Chemical Co. and was used as received. Commer-
cially available reagents were used without purification. All
reaction mixtures were stirred magnetically and were moni-
tored by thin-layer chromatography using silica gel pre-
coated glass plates, which were visualized with UV light and
then, developed using either iodine or a solution of anisalde-
hyde. Flash column chromatography was carried out using
silica gel (230–400 mesh). 1H NMR (400 MHz), 13C NMR
(100 MHz) and 31P NMR (121 MHz) spectra were recorded
on a Bruker NMR spectrometer. Deuterated chloroform
was used as the solvent and chemical shift values (d) are re-
ported in parts per million relative to the residual signals of
773 cmÀ1
;
HR-MS (EI): m/z=314.1075, calcd. for
C18H19O3P: 314.1072.
Ethyl phenyl ethynylphosphonate (1b): yield: 250 mg
(24%); Rf =0.25 (EtOAc:hexane=1:5); colorless oil;
1H NMR (400 MHz, CDCl3): d=7.38–7.32 (m, 2H), 7.26–
7.18 (m, 3H), 4.36–4.27 (m, 2H), 2.94 (d, J=13.72 Hz 2H),
1.42 (td, J1 =0.76 Hz, J2 =7.08 Hz, 3H); 13C NMR
(100 MHz, CDCl3): d=149.7 (d, J=7.15 Hz), 129.6, 125.5 (d,
J=1.24 Hz), 120.5 (d, J=5.08 Hz), 88.9 (d, J=52.12 Hz),
73.8 (d, J=299.17 Hz), 64.3 (d, J=5.86 Hz), 16.0 (d, J=
7.05 Hz); 31P NMR (121 MHz, CDCl3): d=À12.59; IR
(film): n=3177, 2987, 2066, 1489, 1273, 1202, 1036, 941,
this solvent (d=7.26 for H and d=77.0 for 13C). Infrared
1
771 cmÀ1
;
HR-MS (EI): m/z=210.0445, calcd. for
spectra were recorded on an FT-IR spectrometer as either
a thin film pressed between two sodium chloride plates or as
a solid suspended in a potassium bromide disk. Mass spec-
trometry was performed on a GC/HR-MS spectrometer
(KBSI) under the electron impact (EI) ionization technique
(magnetic sector–electric sector double focusing mass ana-
lyzer). Melting points were determined in open capillary
tubes using a Electrothermal 9100 apparatus.
C10H11O3P: 210.0446.
Ethyl phenyl hex-1-ynylphosphonate (1c): yield: 300 mg
(74%); Rf =0.3 (EtOAc:hexane=1:5); colorless oil;
1H NMR (400 MHz, CDCl3): d=7.37–7.30 (m, 2H), 7.25–
7.21 (m, 2H), 7.21–7.15 (m, 1H), 4.31–4.22 (m, 2H), 2.34–
2.27 (m, 2H), 1.55–1.46 (m, 2H), 1.40 (td, J1 =0.70 Hz, J2 =
7.07 Hz, 3H), 1.37–1.30 (m, 2H), 0.88 (t, J=7.30 Hz, 3H);
13C NMR (100 MHz, CDCl3): d=150.1 (d, J=6.89 Hz),
129.6, 125.1, 120.6 (d, J=4.99 Hz), 104.8 (d, J=54.34 Hz),
70.0 (d, J=313.49 Hz), 63.7 (d, J=5.89 Hz), 29.2 (d, J=
2.42 Hz), 21.7, 18.9 (d, J=4.74 Hz), 16.0 (d, J=7.08 Hz),
13.3; 31P NMR (121 MHz, CDCl3): d=À10.25; IR (film): n=
2960, 2205, 1592, 1489, 1274, 1205, 1026, 933, 770 cmÀ1; HR-
MS (EI): m/z=266.1069, calcd. for C14H19O3P: 266.1072.
Ethyl phenyl phenylethynylphosphonate (1d): yield:
109 mg (27%); Rf =0.11 (EtOAc:hexane=1:5); colorless oil;
Preparation of Aryl Alkynylphosphonates[10a]
The terminal alkyne (1 equiv.) was dissolved in THF (0.3M)
at À788C in a flame-dried round bottom flask. A 1.6M solu-
tion of n-BuLi (1.1 equiv.) in hexanes was added and the so-
lution stirred at À788C for 30 min. To the mixture was then
added chlorophosphonate (1.5 equiv) at À788C. The reac-
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1H NMR (400 MHz, CDCl3): d=7.54–7.49 (m, 2H), 7.48–
7.42 (m, 1H), 7.40–7.33 (m, 4H), 7.33–7.27 (m, 2H), 7.24–
7.16 (m, 1H), 4.40–4.30 (m, 2H), 1.44 (td, J1 =0.74 Hz, J2 =
7.07 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=150.1 (d, J=
7.27 Hz), 132.6 (d, J=2.40 Hz), 130.0, 129.7, 128.5, 125.4 (d,
J=1.19 Hz), 120.7 (d, J=4.60 Hz), 119.2 (d, J=5.85 Hz),
100.5 (d, J=55.01 Hz), 77.8 (d, J=310.91 Hz), 61.4 (d, J=
5.87 Hz), 16.1 (d, J=7.21 Hz); 31P NMR (121 MHz, CDCl3):
d=À9.96; IR (film): n=2984, 2186, 1488, 1274, 1202, 1025,
935, 859, 759, 689 cmÀ1; HR-MS (EI): m/z=286.0756, calcd.
for C16H15O3P: 286.0759.
7.30 (m, 10H), 7.25–7.19 (m, 2H); 13C NMR (100 MHz,
CDCl3): d=150.0 (d, J=7.36 Hz), 132.7 (d, J=2.77 Hz),
131.1, 129.8, 128.6, 125.6 (d, J=1.46 Hz), 120.8 (d, J=
4.65 Hz), 118.8 (d, J=5.78 Hz), 102.0 (d, J=55.33 Hz), 77.3
(d, J=320.28 Hz); 31P NMR (121 MHz, CDCl3): d=À14.24;
IR (film): n=3065, 2186, 1590, 1487, 1285, 1186, 949 cmÀ1
;
HR-MS (EI): m/z=334.0761, calcd. for C20H15O3P:
334.0759.
Diphenyl (4-methoxyphenyl)ethynylphosphonate (1j):
yield: 255 mg (28%); Rf =0.2 (EtOAc:hexane=1:3); pale
yellow oil; 1H NMR (400 MHz, CDCl3): d=7.46–7.27 (m,
10H), 7.25–7.16 (m, 2H), 6.89–6.81 (m, 2H), 3.82 (s, 3H);
13C NMR (100 MHz, CDCl3): d=161.8, 150.1 (d, J=
7.54 Hz), 134.5 (d, J=2.40 Hz), 129.8, 125.5 (d, J=1.27 Hz),
120.8 (d, J=4.68 Hz), 114.3, 110.6 (d, J=6.32 Hz), 102.9 (d,
J=56.58 Hz), 76.2 (d, J=322.93 Hz), 55.4; 31P NMR
(121 MHz, CDCl3): d=À13.66; IR (film): n=3070, 2181,
1602, 1488, 1257, 1186, 947, 784, 689 cmÀ1; HR-MS (EI):
m/z=364.0866, calcd. for C21H17O4P: 364.0864.
Ethyl o-tolyl hex-1-ynylphosphonate (4a): yield: 262 mg
(65%); Rf =0.2 (EtOAc:hexane=1:3); pale yellow oil;
1H NMR (400 MHz, CDCl3): d=7.35–7.28 (m, 1H), 7.23–
7.01 (m, 3H), 4.32–4.20 (m, 2H), 2.32 (s, 3H), 2.36–2.27 (m,
2H), 1.55–1.40 (m, 2H), 1.40 (td, J1 =0.70 Hz, J2 =7.07 Hz,
3H), 1.38–1.31 (m, 2H), 0.88 (t, J=7.30 Hz, 3H); 13C NMR
(100 MHz, CDCl3): d=148.8 (d, J=7.35 Hz), 131.2, 126.8,
125.0 (d, J=1.26 Hz), 120.4 (d, J=2.98 Hz), 104.3 (d, J=
54.14 Hz), 70.3 (d, J=312.42 Hz), 63.6 (d J=5.85 Hz), 29.2
(d, J=2.14 Hz), 21.7, 18.9 (d, J=4.60 Hz), 16.5, 16.1 (d, J=
7.15 Hz), 13.3; 31P NMR (121 MHz, CDCl3): d=À10.50; IR
(film): n=3495, 2960, 2872, 2205, 1492, 1271, 1227, 1179,
1111, 1036, 943, 762 cmÀ1; HR-MS (EI): m/z=280.1231,
calcd. for C15H21O3P: 280.1228.
Ethyl phenyl (4-chlorophenyl)ethynylphosphonate (1e):
yield: 368 mg (23%); Rf =0.3 (EtOAc:hexane=1:3); pale
yellow oil; 1H NMR (400 MHz, CDCl3): d=7.46–7.41 (m,
2H), 7.39–7.31 (m, 4H), 7.30–7.26 (m, 2H), 7.24–7.18 (m,
1H), 4.40–4.26 (m, 2H), 1.44 (td, J1 =0.72 Hz, J2 =7.08 Hz,
3H); 13C NMR (100 MHz, CDCl3): d=150.0 (d, J=
7.21 Hz), 137.3, 133.8 (d, J=2.32 Hz), 129.7, 129.0, 125.4,
120.6 (d, J=4.76 Hz), 117.6 (d, J=5.87 Hz), 99.0 (d, J=
54.37 Hz), 78.8 (d, J=328.04 Hz), 64.1 (d, J=5.87 Hz), 16.1
(d, J=6.93 Hz); 31P NMR (121 MHz, CDCl3): d=À10.37;
IR (film): n=2984, 2188, 1488, 1275, 1202, 1090, 1035, 937,
768, 702 cmÀ1
; HRMS (EI): m/z=320.0370, calcd. for
C16H14ClO3P: 320.0369.
Ethyl phenyl (4-bromophenyl)ethynylphosphonate (1f):
yield: 383 mg (21%), Rf =0.3 (EtOAc:hexane=1:3); color-
1
less oil; H NMR (400 MHz, CDCl3): d=7.55–7.48 (m, 2H),
7.41–7.31 (m, 4H), 7.31–7.25 (m, 2H), 7.25–7.17 (m, 1H),
4.41–4.27 (m, 2H), 1.43 (td, J1 =0.72 Hz, J2 =7.08 Hz, 3H);
13C NMR (100 MHz, CDCl3): d=150.0 (d, J=7.08 Hz),
133.9 (d, J=2.70 Hz), 132.0, 129.7, 125.6 (d, J=29.97 Hz),
120.6 (d, J=4.67 Hz), 120.0 (d, J=5.01 Hz), 118.1 (d, J=
5.86 Hz), 99.1 (d, J=54.21 Hz), 79.1 (d, J=309.33 Hz), 64.1
(d, J=5.88 Hz), 16.1 (d, J=6.99 Hz); 31P NMR (121 MHz,
CDCl3): d=À10.40; IR (film): n=2983, 2187, 1586, 1486,
1276, 1201, 1029, 936, 861, 768, 688 cmÀ1; HR-MS (EI):
m/z=363.9861, calcd. for C16H14BrO3P: 363.9864.
Ethyl m-tolyl hex-1-ynylphosphonate (4b): yield: 262 mg
(65%); Rf =0.2 (EtOAc: hexane=1:3); pale yellow oil;
1H NMR (400 MHz, CDCl3): d=7.21 (t, J=7.84 Hz, 1H),
7.09–6.96 (m, 3H), 4.32–4.19 (m, 2H), 2.34 (s, 3H), 2.38–
2.28 (m, 2H), 1.56–1.40 (m, 2H), 1.39 (td, J1 =0.65 Hz, J2 =
10.61 Hz, 3H), 1.41–1.30 (m, 2H), 0.88 (t, J=7.30 Hz, 3H);
13C NMR (100 MHz, CDCl3): d=150.0 (d, J=7.12 Hz),
139.8, 129.3, 125.9, 121.2, 117.5, 104.6 (d, J=54.28 Hz), 70.1
(d, J=313.16 Hz), 63.6 (d, J=5.75 Hz), 29.2 (d, J=2.18 Hz),
21.7, 21.3, 18.9 (d, J=4.81 Hz), 16.0 (d, J=7.18 Hz), 13.4;
31P NMR (121 MHz, CDCl3): d=À10.27; IR (film): n=3495,
2959, 2872, 2205, 1610, 1587, 1487, 1274, 1147, 1032, 865,
Diphenyl ethynylphosphonate (1g): yield: 92 mg (36%),
Rf =0.25 (EtOAc:hexane=1:5); Colorless oil; 1H NMR
(400 MHz, CDCl3) d 7.41–7.34 (m, 4H), 7.31–7.26 (m, 4H),
7.25–7.20 (m, 2H), 2.99 (d, J=14.20 Hz); 13C NMR
(100 MHz, CDCl3) d 149.6 (d, J=7.37 Hz), 129.9, 125.9 (d,
J=1.28 Hz), 120.6 (d, J=5.01 Hz), 90.4 (d, J=53.12 Hz),
73.1 (d, J=308.95 Hz); 31P NMR (121 MHz, CDCl3) d
À16.97; IR (film): 2981, 2242, 1592, 1470, 1276, 1194, 1028,
974,
776 cmÀ1
;
HRMS
(EI):
785, 688 cmÀ1
; HR-MS (EI): m/z=280.1229, calcd. for
m/z calcd for C22H17Cl2O3P: 258.0446; found : 258.0443.
C15H21O3P: 280.1228.
Diphenyl 5-chloropent-1-ynylphosphonate (1h): yield:
287 mg (21%); Rf =0.2 (EtOAc:hexane=1:3); pale yellow
oil; 1H NMR (400 MHz, CDCl3): d=7.40–7.34 (m, 4H),
7.29–7.26 (m, 3H), 7.25–7.19 (m, 3H), 3.45 (t, J=6.20 Hz,
2H), 2.54–2.47 (m, 2H), 1.92 (sep, J=6.52 Hz, 2H);
13C NMR (100 MHz, CDCl3): d=149.9 (d, J=7.38 Hz),
129.8, 125.6 (d, J=1.28 Hz), 120.7 (d, J=4.64 Hz), 104.0 (d,
J=54.75 Hz), 70.6 (d, J=319.59 Hz), 42.8, 29.8 (d, J=
2.23 Hz), 16.6 (d, J=4.28 Hz); 31P NMR (121 MHz, CDCl3):
d=À15.12; IR (film): n=2963, 2207, 1590, 1488, 1282, 1186,
1024, 948, 771 cmÀ1; HR-MS (EI): m/z=334.0529, calcd. for
C17H16ClO3P: 334.0526.
Ethyl p-tolyl hex-1-ynylphosphonate (4c): yield: 222 mg
(64%); Rf =0.2 (EtOAc:hexane=1:3); colorless oil;
1H NMR (400 MHz, CDCl3): d=7.12 (s, 4H), 4.30–4.20 (m,
2H), 2.33–2.28 (m 5H), 1.56–1.46 (2H), 1.38 (td, J1 =
0.69 Hz, J2 =10.63 Hz, 3H), 1.38–1.30 (m, 2H), 0.88 (t, J=
7.30 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=147.9 (d, J=
7.33 Hz), 134.7, 130.0, 120.3 (d, J=4.94 Hz), 104.6 (d, J=
54.03 Hz), 70.09 (d, J=312.64 Hz), 63.6 (d, J=5.83 Hz), 29.2
(d, J=2.31 Hz), 21.7, 20.7, 18.9 (d, J=4.52 Hz), 16.0 (d, J=
7.12 Hz), 13.4; 31P NMR (121 MHz, CDCl3): d=À10.01; IR
(film): n=3494, 2959, 2872, 2205, 1507, 1272, 1204, 1036,
960, 824 cmÀ1
; HR-MS (EI): m/z=280.1227, calcd. for
Diphenyl phenylethynylphosphonate (1i): yield: 316 mg
(20%), Rf =0.32 (EtOAc:hexane=1:4); colorless oil;
1H NMR (400 MHz, CDCl3): d=7.48–7.42 (m, 3H), 7.41–
C15H21O3P: 280.1228.
3,5-Dimethylphenyl ethyl ethynylphosphonate (4d): yield:
247 mg (37%); Rf =0.2 (EtOAc:hexane=1:5); colorless oil;
2878
asc.wiley-vch.de
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2013, 355, 2873 – 2883

Gold-Catalyzed Hydroarylation of Aryl Alkynylphosphonates for the Synthesis of Phosphacoumarins
1H NMR (400 MHz, CDCl3): d=6.86 (s, 2H), 6.83 (s, 1H),
4.36–4.24 (m, 2H), 2.92 (d, J=13.68 Hz, 1H), 2.30 (s, 6H)
1.42 (td, J=0.76 Hz, 3H); 13C NMR (100 MHz, CDCl3) d
149.6 (d, J=7.74 Hz), 139.6, 127.2 (d, J=1.25 Hz), 118.0 (d,
J=4.67 Hz), 88.6 (d, J=51.91 Hz), 73.9 (d, J=298.87 Hz),
64.2 (d, J=5.95 Hz), 21.2, 16.0 (d, J=6.94 Hz); 31P NMR
(121 MHz, CDCl3): d=À12.63; IR (film): n=3175, 2986,
2065, 1593, 1272, 1141, 1028, 862, 788, 684 cmÀ1; HR-MS
(EI): m/z=238.0756, calcd. for C12H15O3P: 238.0759.
3,5-Dimethylphenyl ethyl phenylethynylphosphonate (4e):
yield: 235 mg (49%); Rf =0.3 (EtOAc:hexane=1:3); pale
yellow oil; 1H NMR (400 MHz, CDCl3): d=7.56–7.43 (m,
3H), 7.40–7.33 (m, 2H), 6.91 (s, 2H), 6.83 (s, 1H), 4.40–4.28
(m, 2H), 2.30 (m, 6H), 1.44 (td, J=0.70 Hz, J=7.07 Hz,
3H); 13C NMR (100 MHz, CDCl3): d=149.9 (d, J=
7.23 Hz), 139.5, 132.6 (d, J=2.38 Hz)„ 130.8, 128.5, 127.0 (d,
J=1.14 Hz), 119.3 (d, J=5.80 Hz), 118.2 (d, J=4.59 Hz),
100.3 (d, J=54.25 Hz), 78.1 (d, J=310.02 Hz), 63.9 (d, J=
5.89 Hz), 21.2, 16.1 (d, J=7.07 Hz); 31P NMR (121 MHz,
CDCl3): d=À10.00; IR (film): n=2983, 2186, 1592, 1275,
1140, 1026, 969, 865, 759 cmÀ1; HR-MS (EI): m/z=314.1069,
calcd. for C18H19O3P: 314.1072.
3,5-Dimethylphenyl ethyl (4-methoxyphenyl)ethynyl-
phosphonate (4f): yield: 186 mg (26%); Rf =0.3 (EtOA-
c:hexane=1:4); colorless oil; 1H NMR (400 MHz, CDCl3):
d=7.46 (d, J=8.80 Hz, 2H), 6.94–6.80 (m, 5H), 4.37–4.27
(m, 2H), 3.83 (s, 3H), 2.29 (s, 6H), 1.43 (t, J=7.08 Hz, 3H);
13C NMR (100 MHz, CDCl3): d=161.5, 150.0 (d, J=
6.93 Hz), 139.5, 134.4 (d, J=2.46 Hz), 126.9 (d, J=1.10 Hz),
118.2 (d, J=4.74 Hz), 114.2, 111.1 (d, J=5.97 Hz), 101.0 (d,
J=55.07 Hz), 76.9 (d, J=312.9 Hz), 63.8 (d, J=5.85 Hz),
55.4, 53.4, 21.1, 16.1 (d, J=6.94 Hz); 31P NMR (121 MHz,
CDCl3): d=À9.46; IR (film): n=2981, 2182, 1603, 1509,
1293, 1256, 1141, 1027, 969, 870, 837, 788 cmÀ1; HR-MS
(EI): m/z=344.1178, calcd. for C19H21O4P: 344.1177.
3,5-Dimethylphenyl ethyl [4-(trifluoromethyl)phenyl]-
ethynylphosphonate (4g): yield: 183 mg (24%); Rf =0.2
(EtOAc:hexane=1:3); colorless oil; 1H NMR (400 MHz,
CDCl3): d=7.63 (s, 4H), 6.90 (s, 2H), 6.84 (s, 1H), 4.40–4.30
(m, 2H), 2.30 (s, 6H), 1.45 (td, J1 =0.64 Hz, J2 =7.08 Hz,
3H); 13C NMR (100 MHz, CDCl3): d=149.8 (d, J=
7.22 Hz), 139.6, 133.0 (d, J=2.19 Hz), 132.9 (d, J=2.34),
132.6, 132.2, 127.1 (d, J=1.15 Hz), 125.5 (q, J=3.69 Hz),
124.7, 123.1 (d, J=5.38 Hz), 122.0, 118.1 (d, J=4.95 Hz),
97.8 (d, J=53.36 Hz), 80.4 (d, J=306.91 Hz), 64.1 (d, J=
6.01 Hz), 21.2, 16.1 (d, J=6.78 Hz); 31P NMR (121 MHz,
CDCl3): d=À10.92; IR (film): n=2965, 2192, 1617, 1323,
1292, 1170, 1135, 1027, 868 cmÀ1; HR-MS (EI): m/z=
382.0944, calcd. for C19H18F3O3P: 382.0946.
985, 854 cmÀ1
; HR-MS (EI): m/z=326.1284, calcd. for
C16H23O5P: 326.1283.
2-Bromophenyl ethyl phenylethynylphosphonate (4i):
yield: 342 mg (20%); Rf =0.2 (EtOAc:hexane=1:3); color-
1
less oil; H NMR (400 MHz, CDCl3): d=7.36–7.57 (m, 1H),
7.57–7.49 (m, 3H), 7.49–7.42 (m, 1H), 7.40–7.28 (m, 3H),
7.11–7.04 (m, 1H), 4.53–4.37 (m, 2H), 1.47 (td, J1 =0.80 Hz,
J2 =7.08 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=147.3 (d,
J=6.35 Hz), 133.6, 132.7 (d, J=2.71 Hz), 131.0, 128.6 (d, J=
1.30 Hz), 128.5, 126.4 (d, J=1.17 Hz), 122.1 (d, J=2.95 Hz),
119.1 (d, J=5.81 Hz), 114.9 (d, J=7.07 Hz), 100.7 (d, J=
55.01 Hz), 77.5 (d, J=313.16 Hz), 64.7 (d, J=6.32 Hz), 16.1
(d, J=7.08 Hz); 31P NMR (121 MHz, CDCl3): d=À10.69;
IR (film): n=2985, 2186, 1474, 1280, 1221, 1033, 931, 860,
758, 688, 657 cmÀ1; HR-MS (EI): m/z=363.9865, calcd. for
C16H14BrO3P: 363.9864.
4-Bromophenyl ethyl phenylethynylphosphonate (4j):
yield: 190 mg (26%); Rf =0.2 (EtOAc:hexane=1:3); color-
1
less oil; H NMR (400 MHz, CDCl3): d=7.55–7.44 (m, 5H),
7.41–7.35 (m, 2H), 7.21–7.10 (m, 2H), 4.41–4.28 (m, 2H),
1.44 (td, J1 =0.74 Hz, J2 =7.07 Hz, 3H); 13C NMR
(100 MHz, CDCl3): d=149.1 (d, J=7.00 Hz), 132.7, 132.7 (d,
J=2.65 Hz), 131.0, 125.6, 122.4 (d, J=4.70 Hz), 118.9 (d, J=
6.10 Hz), 118.4 (d, J=2.01 Hz), 100.8 (d, J=54.8 Hz), 77.4
(d, J=312.25 Hz), 64.2 (d, J=5.88 Hz), 16.1 (d, J=6.80 Hz);
31P NMR (121 MHz, CDCl3): d=À10.05; IR (film): n=2984,
2186, 1483, 1274, 1208, 1034, 926, 860, 756 cmÀ1; HR-MS
(EI): m/z=363.9865, calcd. for C16H14BrO3P: 363.9864.
3,5-Dimethylphenyl ethyl hex-1-ynylphosphonate (4k):
yield: 393 mg (56%); Rf =0.3 (EtOAc:hexane=1:5); pale
yellow oil; 1H NMR (400 MHz, CDCl3): d=6.85 (s, 2H),
6.81 (s, 1H), 4.30–4.19 (m, 2H), 2.65–2.30 (m, 2H), 2.29 (s,
6H), 1.56–1.47 (m, 2H), 1.39 (td, J1 =0.72 Hz, J2 =7.08 Hz,
3H), 1.37–1.28 (m, 2H), 0.89 (t, J=7.30 Hz, 3H); 13C NMR
(100 MHz, CDCl3): d=150.0 (d, J=7.19 Hz), 139.4, 126.8 (d,
J=1.11 Hz), 118.1 (d, J=4.94 Hz), 104.5 (d, J=54.27 Hz),
70.21 (d, J=313.1 Hz), 63.6 (d, J=5.82 Hz), 29.2 (d, J=
2.14 Hz), 21.7, 21.2, 18.9 (d, J=4.48 Hz), 16.0 (d, J=
7.16 Hz), 13.4; 31P NMR (121 MHz, CDCl3): d=À10.28; IR
(film): n=2959, 2206, 1593, 1466, 1273, 1142, 1027, 967,
855 cmÀ1
;
HR-MS (EI): m/z=294.1382, calcd. for
C16H23O3P: 294.1385.
3,5-Dimethylphenyl ethyl 5-chloropent-1-ynylphosphonate
(4l): yield: 287 mg (21%); Rf =0.3 (EtOAc:hexane=1:2);
1
colorless oil; H NMR (400 MHz, CDCl3): d=6.85 (s, 2H),
6.82 (s, 1H), 4.31–4.21 (m, 2H), 3.56–3.51 (m, 2H), 2.56–
2.50 (m, 2H), 2.30 (s, 6H), 2.01–1.94 (m, 2H), 1.40 (td, J1 =
0.72 Hz, J2 =7.06 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=
149.9 (d, J=7.16 Hz), 139.5, 127.0 (d, J=1.18 Hz), 118.1 (d,
J=4.94 Hz), 102.0 (d, J=53.77 Hz), 71.3 (d, J=310.34 Hz),
63.7 (d, J=5.93 Hz), 42.8, 29.9 (d, J=2.38 Hz), 21.1, 16.6 (d,
J=4.83 Hz), 16.0 (d, J=7.10 Hz); 31P NMR (121 MHz,
CDCl3): d=À10.83; IR (film): n=2920, 2207, 1592, 1472,
1272, 1141, 1026, 968, 856, 773 cmÀ1; HR-MS (EI): m/z=
314.0840, calcd. for C15H20O3P: 314.0839.
3,5-Dimethoxyphenyl ethyl hex-1-ynylphosphonate (4h):
yield: 163 mg (50%); Rf =0.3 (EtOAc:hexane=1:4); color-
1
less oil; H NMR (400 MHz, CDCl3): d=6.44–6.41 (m, 2H),
6.30–6.27 (m, 1H), 4.32–4.20 (m, 2H), 3.77 (s, 6H), 2.36–
2.28 (m, 2H), 1.56–1.48 (m, 2H), 1.40 (td, J1 =0.64 Hz, J2 =
7.08 Hz, 3H), 1.40–1.33 (m, 2H), 0.88 (t, J=7.30 Hz, 3H);
13C NMR (100 MHz, CDCl3): d=161.2, 151.6 (d, J=
6.88 Hz), 104.8 (d, J=54.37 Hz), 99.2 (d, J=5.03 Hz), 97.6,
69.9 (d, J=314.17 Hz), 63.7 (d, J=5.87 Hz), 55.5, 53.4, 29.2
(d, J=2.17 Hz), 21.8, 18.9 (d, J=4.55 Hz), 16.1 (d, J=
6.97 Hz), 13.4; 31P NMR (121 MHz, CDCl3): d=À10.48; IR
(film): n=2959, 2204, 1597, 1475, 1273, 1205, 1155, 1035,
General Procedure for the Preparation of
Phosphacoumarin Derivatives
A suspension of Ph3PAuCl (4.9 mg, 0.5ꢂ10À2 mmol) and
AgOTf (2.5 mg, 0.5ꢂ10À2 mmol) in 1,2-dicloroethane
(0.8 mL) was stirred at 258C for 10 min. To this suspension
Adv. Synth. Catal. 2013, 355, 2873 – 2883
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
2879

Cheol-Eui Kim et al.
FULL PAPERS
were added TfOH (90.64 mg, 0.6 mmol) and diphenyl hex-1-
ynylphosphonate (1a) (62.8 mg, 0.2 mmol) in 1,2-dicloro-
ethane (0.2 mL). After being stirred at 808C for 17 h, the re-
action mixture was quenched with aqueous Na2CO3. The
aqueous layer was extracted with ether (3ꢂ5 mL), and the
combined organic layers were washed with water and brine,
filtered and concentrated under reduced pressure. Silica gel
column chromatography (acetone:hexane=1:3) gave 2-
phenoxy-4-butyl-1,2l5-benzoxaphosphinine 2-oxide (2a).
2-Phenoxy-4-butyl-1,2l5-benzoxaphosphinine 2-oxide (2a):
Rf =0.2 (acetone:hexane=1:3); pale yellow solid; mp 60–
2-Ethoxy-4-(4-chlorophenyl)-1,2l5-benzoxaphosphinine 2-
oxide (2e): Rf =0.3 (acetone:hexane=1:2); brown oil;
1H NMR (400 MHz, CDCl3): d=7.49–7.38 (m, 3H), 7.33–
7.28 (m, 2H), 7.26–7.22 (m, 1H), 7.19–7.13 (m, 1H), 7.11–
7.05 (m, 1H), 6.06 (d, J=17.56 Hz, 1H), 4.33–4.21 (m, 2H),
1.38 (t, J=7.06 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=
155.0 (d, J=2.27 Hz), 151.5 (d, J=7.90 Hz), 136.9 (d, J=
19.73 Hz), 135.2, 131.5, 129.7, 129.0, 128.9, 123.6, 121.4 (d,
J=16.11 Hz), 119.4 (d, J=7.66 Hz), 111.9 (d, J=174.69 Hz),
63.2 (d, J=6.60 Hz), 16.5 (d, J=5.84 Hz); 31P NMR
(121 MHz, CDCl3): d=8.13; IR (film): n=3485, 2982, 1597,
1267, 1217, 1034, 954, 806, 765 cmÀ1; HR-MS (EI): m/z=
230.0367, calcd. for C16H14ClO3P: 230.0369.
1
658C; H NMR (400 MHz, CDCl3): d=7.57–7.51 (m, 1H),
7.42–7.36 (m, 1H), 7.30–7.24 (m, 2H), 7.22–7.18 (m, 2H),
7.18–7.10 (m, 3H), 6.09 (d, J=17.96 Hz, 1H), 2.76–2.65 (m,
2H), 1.64–1.54 (m, 2H), 1.46–1.35 (m, 2H), 0.94 (t, J=
7.32 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=157.3, 151.4
(d, J=8.32 Hz), 149.9 (d, J=8.52 Hz), 131.3, 129.6 (d, J=
0.99 Hz), 126.2, 125.2, 123.9, 121.2 (d, J=17.09 Hz), 120.8
(d, J=4.37 Hz), 119.4 (d, J=7.95 Hz), 108.3 (d, J=
176.04 Hz), 34.8 (d, J=18.15 Hz), 30.1, 22.4, 13.8; 31P NMR
(121 MHz, CDCl3): d=6.21; IR (film): n=3068, 2957, 1600,
1488, 1273, 1273, 1196, 1125, 932, 764, 690 cmÀ1; HR-MS
(EI): m/z=314.1074, calcd. for C18H19O3P: 314.1072.
2-Ethoxy-4-(4-bromophenyl)-1,2l5-benzoxaphosphinine 2-
oxide (2f): Rf =0.2 (acetone:hexane=1:3); pale yellow oil;
1H NMR (400 MHz, CDCl3): d=7.63–7.57 (m, 2H), 7.44–
7.36 (m, 1H), 7.26–7.22 (m, 3H), 7.18–7.05 (m, 2H), 6.06 (d,
J=17.48 Hz, 1H), 4.33–4.21 (m, 2H), 1.38 (t, J=7.06 Hz,
3H); 13C NMR (100 MHz, CDCl3): d=155.0 (d, J=
2.58 Hz), 151.6 (d, J=7.97 Hz), 137.4 (d, J=19.64 Hz),
131.9, 131.5, 130.0, 129.0, 123.6, 123.4, 121.3 (d, J=
16.10 Hz), 119.4 (d, J=7.64 Hz), 111.9 (d, J=174.91 Hz),
63.2 (d, J=6.51 Hz), 16.5 (d, J=5.81 Hz); 31P NMR
(121 MHz, CDCl3): d=8.04; IR (film): n=3469, 2982, 1480,
1267, 1217, 1033, 954, 900, 805 cmÀ1; HR-MS (EI): m/z=
358.0968, calcd. for C16H14BrO3P: 358.0970.
2-Ethoxy-1,2l5-benzoxaphosphinine 2-oxide (2b): Rf =0.3
1
(acetone:hexane=1:2); pale yellow oil; H NMR (400 MHz,
CDCl3): d=7.49–7.29 (m, 3H), 7.20–7.13 (m, 2H), 6.15 (dd,
J1 =18.44 Hz, J2 =12.56 Hz, 1H), 4.25–4.16 (m, 2H), 1.36 (t,
J=7.08 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=151.7 (d,
J=9.21 Hz), 144.7, 131.2, 129.8 (d, J=1.42 Hz), 123.8, 120.5
(d, J=19.76 Hz), 118.7 (d, J=7.21 Hz), 112.5 (d, J=
171.01 Hz), 63.1 (d, J=6.57 Hz), 16.4 (d, J=6.22 Hz);
31P NMR (121 MHz, CDCl3): d=8.13; IR (film): n=3476,
2984, 1604, 1484, 1259, 1220, 1032, 935, 782 cmÀ1; HR-MS
(EI): m/z=210.0445, calcd. for C10H11O3P: 210.0446.
2-Phenoxy-1,2l5-benzoxaphosphinine 2-oxide (2g): Rf =
0.3 (acetone:hexane=1:2); pale yellow oil; 1H NMR
(400 MHz, CDCl3): d=7.53–7.36 (m, 2H), 7.34–7.27 (m,
3H), 7.21–7.12 (m, 5H), 6.28 (dd, J1 =19.16 Hz, J2 =
12.56 Hz, 1H); 13C NMR (100 MHz, CDCl3): d=151.6 (d,
J=9.54 Hz), 149.8 (d, J=8.50 Hz), 145.6, 131.5, 130.0 (d, J=
1.42 Hz), 129.7, 125.4, 124.2, 120.7 (d, J=4.42 Hz), 118.7 (d,
J=7.34 Hz), 115.4, 112.0 (d, J=173.07 Hz); 31P NMR
(121 MHz, CDCl3): d=4.44; IR (film): n=3284, 3060, 1605,
1487, 1275, 1194, 1102, 938, 776, 690 cmÀ1; HR-MS (EI):
m/z=258.0449, calcd. for C14H11O3P: 258.0446.
2-Ethoxy-4-butyl-1,2l5-benzoxaphosphinine 2-oxide (2c):
Rf =0.2 (acetone:hexane=1:3); colorless oil; 1H NMR
(400 MHz, CDCl3): d=7.59–7.51 (m, 1H), 7.41–7.33 (m,
1H), 7.22–7.13 (m, 2H), 5.98 (d, J=17.20 Hz, 1H), 4.24–
4.11 (m, 2H), 2.75–2.62 (m, 2H), 1.67–1.58 (m, 2H), 1.50–
1.39 (m, 2H), 1.34 (t, J=7.06 Hz, 3H), 0.96 (t, J=7.27 Hz,
3H); 13C NMR (100 MHz, CDCl3): d=156.1 (d, J=
1.19 Hz), 151.5 (d, J=8.05 Hz), 131.0, 126.0, 123.6, 121.2 (d,
J=16.94 Hz), 119.4 (d, J=7.57 Hz), 108.9 (d, J=176.02 Hz),
62.8 (d, J=6.51 Hz), 34.7 (d, J=18.37 Hz), 30.1, 22.5, 16.4
(d, J=5.94 Hz), 13.8; 31P NMR (121 MHz, CDCl3): d=9.87;
IR (film): n=3484, 2957, 1602, 1445, 1264, 1035, 929,
763 cmÀ1; HR-MS (EI): m/z=266.1074, calcd for C14H19O3P:
266.1072.
2-Phenoxy-4-(3-chloropropyl)-1,2l5-benzoxaphosphinine
2-oxide (2h): Rf =0.3 (acetone:hexane=1:2); brown solid;
1
mp 57–628C; H NMR (400 MHz, CDCl3): d=7.39 (d, J=
7.88 Hz) 7.60–7.53 (m, 1H), 7.47–7.39 (m, 1H), 7.33–7.27
(m, 2H), 7.25–7.19 (m, 2H), 7.18–7.11 (m, 3H), 6.14 (d, J=
17.32 Hz, 1H), 3.65–3.51 (m, 2H), 2.98–2.81 (m, 2H), 2.14–
2.03 (m, 2H); 13C NMR (100 MHz, CDCl3): d=155.4, 151.5
(d, J=8.67 Hz), 149.9 (d, J=8.29 Hz), 131.6, 129.7, 126.1,
125.3, 124.1, 120.7 (d, J=4.41 Hz), 119.6 (d, J=8.00 Hz),
115.3, 109.5 (d, J=175.71 Hz), 43.8, 32.1 (d, J=19.13 Hz),
30.7; 31P NMR (121 MHz, CDCl3): d=5.27; IR (film): n=
3291, 2960, 1593, 1488, 1271, 1195, 935, 761, cmÀ1; HR-MS
(EI): m/z=334.0523, calcd. for C17H16ClO3P: 334.0526.
2-Ethoxy-4-phenyl-1,2l5-benzoxaphosphinine
2-oxide
2-Phenoxy-4-phenyl-1,2l5-benzoxaphosphinine
2-oxide
(2d): Rf =0.3 (acetone:hexane=1:5); white solid; mp 78–
1
838C; H NMR (400 MHz, CDCl3): d=7.49–7.43 (m, 3H),
(2i): Rf =0.2 (acetone:hexane=1:3); pale yellow solid; mp
75–808C; 1H NMR (400 MHz, CDCl3): d=7.51–7.44 (m,
4H), 7.37–7.27 (m, 5H), 7.23–7.14 (m, 4H), 7.14–7.06 (m,
1H), 6.18 (d, J=18.68, 1H); 13C NMR (100 MHz, CDCl3):
d=157.4 (d, J=2.21 Hz), 151.6 (d, J=8.24 Hz), 138.3 (d, J=
19.7 Hz), 134.1 (d, J=13.7 Hz), 131.7, 129.7, 129.5, 129.3,
128.6, 128.3, 125.4 (d, J=1.15 Hz), 123.9, 120.8 (d, J=
4.37 Hz), 119.3 (d, J=7.85 Hz), 115.4, 110.6 (d, J=
174.01 Hz); 31P NMR (121 MHz, CDCl3): d=5.01; IR (film):
n=3057, 1590, 1488, 1343, 1193, 932, 768 cmÀ1; HR-MS
(EI): m/z=334.0757, calcd. for C20H15O3P: 334.0759.
7.42–7.34 (m, 3H), 7.25–7.18 (m, 2H), 7.12–7.03 (m,1H),
6.07 (d, J=17.96 Hz, 1H), 4.32–4.21 (m, 2H), 1.38 (t, J=
7.08 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=156.3 (d, J=
2.24 Hz), 151.6 (d, J=8.02 Hz), 138.6 (d, J=19.54 Hz),
131.3, 129.3, 129.3, 129.0, 128.6, 128.4, 123.5, 121.7 (d, J=
16.19 Hz), 119.3 (d, J=7.71 Hz), 111.4 (d, J=174.26 Hz),
63.1 (d, J=6.59 Hz), 16.5 (d, J=5.88 Hz); 31P NMR
(121 MHz, CDCl3): d=8.66; IR (film): n=2983, 1591, 1445,
1267, 1106, 1034, 897, 770, 562 cmÀ1; HR-MS (EI): m/z=
286.0762, calcd. for C16H15O3P: 286.0759.
2880
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Adv. Synth. Catal. 2013, 355, 2873 – 2883

Gold-Catalyzed Hydroarylation of Aryl Alkynylphosphonates for the Synthesis of Phosphacoumarins
2-Phenoxy-4-(4-methoxyphenyl)-1,2l5-benzoxaphosphin-
ine 2-oxide (2j): Rf =0.3 (acetone:hexane=1:3); yellow oil;
1H NMR (400 MHz, CDCl3): d=7.44–7.38 (m, 1H), 7.34–
7.24 (m, 6H), 7.19–7.08 (m, 4H), 7.00–6.96 (m, 2H), 6.14 (d,
J=18.96 Hz, 1H), 3.87 (s, 3H); 13C NMR (100 MHz,
CDCl3): d=160.5, 157.0 (d, J=2.52 Hz), 151.7 (d, J=
8.36 Hz), 149.9 (d, J=8.22 Hz), 131.5, 130.7, 130.5, 129.8,
129.7, 129.6, 125.3 (d, J=1.17 Hz), 123.8, 121.9 (d, J=
16.0 Hz), 120.8 (d, J=4.39 Hz), 119.3 (d, J=7.94 Hz), 114.0,
109.9 (d, J=174.71 Hz), 55.4; 31P NMR (121 MHz, CDCl3):
d=5.48; IR (film): n=3319, 2961, 1607, 1509, 1253, 1253,
1192, 933, 800, 769 cmÀ1; HR-MS (EI): m/z=364.0865,
calcd. for C17H17O4P: 364.0864.
d=152.3 (d, J=9.47 Hz), 141.9, 141.4, 137.0 (d, J=1.38 Hz),
126.6, 117.3 (d, J=6.81 Hz), 116.6 (d, J=18.29 Hz), 110.7 (d,
J=173.63 Hz), 62.9 (d, J=6.56 Hz), 21.4, 19.0, 16.5 (d, J=
6.01 Hz); 31P NMR (121 MHz, CDCl3): d=8.30; IR (film):
n=3291, 2978, 1598, 1374, 1259, 1158, 1033, 849, 789,
783 cmÀ1
;
HR-MS (EI): m/z=238.0760, calcd. for
C12H15O3P: 238.0759.
5,7-Dimethyl-2-ethoxy-4-phenyl-1,2l5-benzoxaphosphinine
2-oxide (5e): Rf =0.35 (acetone:hexane=1:1); pale yellow
1
solid; mp 77–828C; H NMR (400 MHz, CDCl3): d=7.43–
7.32 (m, 3H), 7.25 (s, 2H), 6.94 (s, 1H), 6.76 (s, 1H), 6.07
(d, J=20.36 Hz, 1H), 4.32–4.17 (m, 2H), 2.33 (s, 3H), 1.69
(s, 3H), 1.23 (t, J=7.08 Hz, 3H); 13C NMR (100 MHz,
CDCl3): d=156.7 (d, J=1.35 Hz), 151.7 (d, J=8.02 Hz),
142.1 (d, J=19.15 Hz), 141.2, 138.2 (d, J=1.27 Hz), 129.0,
128.7, 128.6, 127.0, 119.8 (d, J=15.89 Hz), 117.6 (d, J=
6.90 Hz), 115.2, 113.5, 62.8 (d, J=6.60 Hz), 23.3, 21.1, 16.4
(d, J=5.53 Hz); 31P NMR (121 MHz, CDCl3): d=9.45; IR
(film): n=2980, 2927, 1585, 1445, 1332, 1273, 1030, 967, 836,
8-Methyl-2-ethoxy-4-butyl-1,2l5-benzoxaphosphinine
2-
oxide (5a): Rf =0.1 (acetone:hexane=1:3); white solid; mp
60–658C; 1H NMR (400 MHz, CDCl3): d=7.39 (d, J=
7.88 Hz, 1H), 7.25 (d, J=7.40 Hz, 1H), 7.07 (d, J=7.70 Hz,
1H), 5.96 (d, J=17.48 Hz, 1H), 4.22–4.10 (m, 2H), 2.77–
2.60 (m, 2H), 2.36 (s, 3H), 1.66–1.55 (m, 2H), 1.49–1.38 (m,
2H), 1.34 (t, J=7.06 Hz, 3H), 0.95 (t, J=7.30 Hz, 3H);
13C NMR (100 MHz, CDCl3): d=156.5, 149.9 (d, J=
8.72 Hz), 132.5, 128.2 (d, J=7.13 Hz), 123.8, 122.9, 120.9 (d,
J=16.68 Hz), 108.6 (d, J=176.53 Hz), 62.7 (d, J=6.60 Hz),
35.0 (d, J=18.51 Hz), 30.2, 22.4, 16.4 (d, J=5.84 Hz), 16.0,
13.8; 31P NMR (121 MHz, CDCl3): d=10.10; IR (film): n=
3482, 2957, 2871, 1573, 1456, 1261, 1189, 1035, 937, 799,
767, 701 cmÀ1
; HR-MS (EI): m/z=314.1069, calcd. for
C18H19O3P: 314.1072.
5,7-Dimethyl-2-ethoxy-4-(4-methoxyphenyl)-1,2l5-benoxa-
phosphinine 2-oxide (5f): Rf =0.1 (acetone:hexane=1:2);
1
white solid; mp 88–938C; H NMR (400 MHz, CDCl3): d=
7.17 (s, 2H), 6.94–6.85 (m, 3H), 6.76 (s, 1H), 6.03 (d, J=
20.60 Hz, 1H), 4.31–4.14 (m, 2H), 3.84 (s, 3H), 2.33 (s, 3H),
1.73 (s, 3H), 1.32 (t, J=7.08 Hz, 3H); 13C NMR (100 MHz,
CDCl3): d=160.0, 156.4, 151.7 (d, J=7.63 Hz), 141.1, 138.3
(d, J=1.44 Hz), 134.5 (d, J=19.20 Hz), 128.9, 128.3, 120.0
(d, J=15.88 Hz), 117.5 (d, J=6.75 Hz), 114.0, 113.2 (d, J=
179.1 Hz), 62.7 (d, J=6.57 Hz), 55.3, 23.4, 21.1, 16.4 (d, J=
5.75 Hz); 31P NMR (121 MHz, CDCl3): d=10.00; IR (film):
n=2970, 2930, 1607, 1509, 1271, 1030, 967, 845 cmÀ1; HR-
MS (EI): m/z=344.1179, calcd. for C19H21O4P: 344.1177.
5,7-Dimethyl-2-ethoxy-4-(4-trifluoromethylphenyl)-1,2l5-
benzoxaphosphinine 2-oxide (5g): Rf =0.4 (acetone:hex-
732 cmÀ1
;
HR-MS (EI): m/z=280.1230, calcd. for
C15H21O3P: 280.1228.
7-Methyl-2-ethoxy-4-butyl-1,2l5-benzoxaphosphinine
2-
oxide (5b): Rf =0.1 (acetone:hexane=1:3); white solid; mp
57–628C; 1H NMR (400 MHz, CDCl3): d=7.40 (d, J=
8.24 Hz, 1H), 7.00–6.95 (m, 2H), 5.98 (d, J=17.44 Hz, 1H),
4.21–4.10 (m, 2H), 2.73–2.58 (m, 2H), 2.37 (s, 3H), 1.66–
1.55 (m, 2H), 1.49–1.38 (m, 2H), 1.33 (t, J=7.06 Hz, 3H),
0.95 (t, J=7.30 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=
156.2, 151.4 (d, J=8.08 Hz), 141.9, 125.8, 124.5, 119.7 (d, J=
7.69 Hz), 118.6 (d, J=16.95 Hz), 107.7 (d, J=176.25 Hz),
62.7 (d, J=6.51 Hz), 34.7 (d, J=18.43 Hz), 30.2, 22.4, 21.2,
16.4 (d, J=5.97 Hz), 13.8; 31P NMR (121 MHz, CDCl3): d=
10.43; IR (film): n=2957, 2930, 2871, 1618, 1598, 1265, 1139,
1038, 967, 842 cmÀ1; HR-MS (EI): m/z=280.1231, calcd. for
C15H21O3P: 280.1228.
1
ane=1:1); pale yellow oil; H NMR (400 MHz, CDCl3): d=
7.65 (d, J=8.08 Hz, 2H), 7.39 (s, 2H), 6.96 (s, 1H), 6.78 (s,
1H), 6.10 (d, J=19.48 Hz, 1H), 4.33–4.18 (m, 2H), 2.35 (s,
3H), 1.68 (s, 3H), 1.34 (t, J=7.08 Hz, 3H); 13C NMR
(100 MHz, CDCl3): d=155.0, 151.6 (d, J=8.07 Hz), 145.6 (d,
J=20.07 Hz), 141.7, 137.7 (d, J=1.26 Hz), 134.1 (d, J=
13.78 Hz), 130.7 (d, J=32.78 Hz), 129.1, 127.4, 125.7, 125.2,
122.5, 119.2 (d, J=15.62 Hz), 117.8 (d, J=6.74 Hz), 115.8 (d,
J=178.59 Hz), 63.0 (d, J=6.57 Hz), 23.6, 21.1, 16.4 (d, J=
5.70 Hz); 31P NMR (121 MHz, CDCl3): d=8.38; IR (film):
n=3477, 2929, 1617, 1585, 1323, 1274, 1166, 1127, 1066,
1030, 851, 801, 735 cmÀ1; HR-MS (EI): m/z=382.0947,
calcd. for C19H18F3O3P: 382.0946.
6-Methyl-2-ethoxy-4-butyl-1,2l5-benzoxaphosphinine
2-
oxide (5c): Rf =0.1 (acetone:hexane=1:3); white solid; mp
59–648C; 1H NMR (400 MHz, CDCl3): d=7.32–7.29 (m,
1H), 7.20–7.14 (m, 1H), 7.06 (d, J=8.28 Hz, 1H), 5.95 (d,
J=17.20 Hz, 1H), 4.21–4.09 (m, 2H), 2.75–2.60 (m, 2H),
2.36 (s, 3H), 1.67–1.57ACTHUNRGTNE(NUG m, 2H), 1.53–1.39 (m, 2H), 1.32 (t,
J=7.08, 3H), 0.97 (t, J=7.30 Hz, 3H); 13C NMR (100 MHz,
CDCl3): d=156.1, 149.4 (d, J=8.05 Hz), 132.9, 131.6, 126.2,
120.9 (d, J=16.73 Hz), 119.11 (d, J=7.48 Hz), 108.8 (d, J=
176.14 Hz), 62.7 (d, J=6.53 Hz), 34.5 (d, J=18.36 Hz), 30.0,
22.4, 20.9, 16.4 (d, J=5.95 Hz), 13.8; 31P NMR (121 MHz,
CDCl3): d=10.18; IR (film): n=2956, 2928, 2871, 1601,
5,7-Dimethoxy-2-ethoxy-4-butyl-1,2l5-benzoxaphoshinine
2-oxide (5h): Rf =0.3 (acetone:hexane=1:2); colorless oil;
1H NMR (400 MHz, CDCl3): d=6.34 (d, J=2.52 Hz, 1H),
6.25 (d, J=2.56 Hz, 1H), 5.73 (d, J=19.76 Hz, 1H), 4.19–
4.09 (m, 2H), 3.823 (s, 3H), 3.820 (s, 3H), 3.00–2.65 (m,
2H), 1.48–1.39 (m, 2H), 1.39–1,31 (m, 2H), 1.30 (t, J=
7.08 Hz, 3H), 0.90 (t, J=7.24 Hz, 3H); 13C NMR (100 MHz,
CDCl3): d=161.6, 159.3 (d, J=1.31 Hz), 158.4, 154.0 (d, J=
7.98 Hz), 106.9 (d, J=177.66 Hz), 96.5, 95.2, 62.4 (d, J=
6.56 Hz), 55.6 (d, J=9.38 Hz), 39.3 (d, J=18.56 Hz), 31.3,
22.5, 16.4 (d, J=5.86 Hz), 13.9; 31P NMR (121 MHz,
CDCl3): d=11.45; IR (film): n=2956, 1615, 1587, 1328,
1567, 1267, 1036, 937, 891 cmÀ1
; HR-MS (EI): m/z=
280.1229, calcd. for C15H21O3P: 280.1228.
5,7-Dimethyl-2-ethoxy-1,2l5-benzoxaphosphinine 2-oxide
(5d): Rf =0.1 (acetone:hexane=1:3); white solid; mp 40–
458C; 1H NMR (400 MHz, CDCl3): d=7.63 (dd, J1 =
44.05 Hz, J2 =12.72 Hz, 1H), 6.81 (d, J=4.12 Hz, 2H), 6.08
(dd, J1 =19.26 Hz, J2 =12.73 Hz, 1H), 2.40 (s, 3H), 2.32 (s,
3H), 1.34 (t, J=7.08 Hz, 3H); 13C NMR (100 MHz, CDCl3):
Adv. Synth. Catal. 2013, 355, 2873 – 2883
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
2881

Cheol-Eui Kim et al.
FULL PAPERS
1264, 1154, 1105, 1035, 844 cmÀ1; HR-MS (EI): m/z=
326.1281, calcd. for C16H23O5P: 326.1283.
2980, 1617, 1453, 1271, 1031, 963, 849 cmÀ1; HR-MS (EI):
m/z=314.0840, calcd. for C15H20ClO3P: 314.0839.
8-Bromol-2-ethoxy-4-phenyl-1,2l5-benzoxaphosphinine 2-
oxide (5i): Rf =0.3 (acetone:hexane=1:3); pale yellow solid;
mp 97–1028C; 1H NMR (400 MHz, CDCl3): d=7.66–7.61
(m, 1H), 7.48–7.44 (m, 3H), 7.37–7.31 (m, 2H), 7.14 (dd,
J1 =1.50 Hz, J2 =7.98 Hz, 1H), 6.95 (t, J=7.96 Hz, 1H), 6.11
(d, J=18.24 Hz, 1H), 4.40–4.24 (m, 2H), 1.41 (t, J=7.08 Hz,
3H); 13C NMR (100 MHz, CDCl3): d=156.0 (d, J=
1.98 Hz), 148.4 (d, J=7.28 Hz), 138.3 (d, J=19.25 Hz),
134.9, 134.1 (d, J=13.78 Hz), 129.2, 128.7, 128.6, 128.3,
124.0, 123.4 (d, J=16.15 Hz), 113.3 (d, J=7.54 Hz), 112.3 (d,
J=176.43 Hz), 63.5 (d, J=6.86 Hz), 16.5 (d, J=5.43 Hz);
31P NMR (121 MHz, CDCl3): d=8.34; IR (film): n=3058,
2982, 1545, 1432, 1275, 1030, 960, 768, 735 cmÀ1; HR-MS
(EI): m/z=363.9865, calcd. for C16H23O5P: 326.1283.
Acknowledgements
This work was supported by the National Research Founda-
tion of Korea (NRF) grant funded by the Korea government
(MSIP) (No. 2011-0018355) and BRL (No. 2009-0087013).
References
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6-Bromol-2-ethoxy-4-phenyl-1,2l5-benzoxaphosphinine 2-
oxide (5j): Rf =0.3 (acetone:hexane=1:3); pale yellow oil;
1H NMR (400 MHz, CDCl3): d=7.52–7.46 (m, 4H), 7.40–
7.29 (m, 3H), 7.18–7.09 (m, 1H), 6.11 (d, J=17.72 Hz, 1H),
4.32–4.22 (m, 2H), 1.38 (t, J=7.08 Hz, 3H); 13C NMR
(100 MHz, CDCl3): d=155.1 (d, J=2.07 Hz), 150.5 (d, J=
7.90 Hz), 137.8 (d, J=19.07 Hz), 134.0, 131.7, 129.4, 128.8,
128.2, 123.5 (d, J=16.21 Hz), 121.0 (d, J=7.59 Hz), 116.2,
112.7 (d, J=174.64 Hz), 63.4 (d, J=6.61 Hz), 16.5 (d, J=
5.83 Hz); 31P NMR (121 MHz, CDCl3): d=8.07; IR (film):
n=3055, 1468, 1262, 1034, 954, 805, 700 cmÀ1; HR-MS (EI):
m/z=363.9866, calcd. for C16H14BrO3P: 363.9864.
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4,6-Dimethyl-3(Z)-(1-pentylene)-1-oxaphosphole 2-oxide
1
(5k): Rf =0.3 (Aaetone:hexane=1:3); colorless oil; H NMR
(400 MHz, CDCl3): d=6.81 (s, 1H), 6.71 (s, 1H), 5.77–5.67
(m, 1H), 4.31–4.15 (m, 2H), 3.04–2.83 (m, 2H), 2.35 (s, 3H),
2.27 (s, 3H), 2.27–2.18 (m, 2H), 1.57–1.47 (m, 2H), 1.33 (t,
J=7.08 Hz, 3H), 0.98 (t, J=7.38 Hz, 3H); 13C NMR
(100 MHz, CDCl3): d=150.4 (d, J=9.70 Hz), 138.1, 135.3 (d,
J=13.22 Hz), 127.5, 124.9 (d, J=7.20 Hz), 123.4 (d, J=
13.79 Hz), 116.9 (d, J=7.26 Hz), 62.5 (d, J=6.75 Hz), 30.3
(d, J=1.74 Hz), 27.6, 26.4, 22.5 (d, J=3.22 Hz), 20.9, 20.7,
16.4 (d, J=5.87 Hz), 13.8; 31P NMR (121 MHz, CDCl3): d=
23.58; IR (film): n=3485, 2959, 2870, 1617, 1455, 1271, 1158,
1031, 964, 850 cmÀ1; HR-MS (EI): m/z=294.1382, calcd. for
C16H23O3P: 294.1385.
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ne:hexane=1:3); colorless oil; H NMR (400 MHz, CDCl3,
data for the major isomer): d=6.83 (s, 1H), 6.72 (s, 1H),
5.79–5.71 (m, 1H), 4.30–4.19 (m, 2H), 3.71–3.60 (m, 2H),
2.94 (d, J=21.04 Hz, 2H), 2.37–2.66 (m, 2H), 2.37 (s, 3H),
1
2.28 (s, 3H), 1.34 (t, J=7.08 Hz, 3H); H NMR (400 MHz,
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1H), 6.06 (d, J=19.28 Hz, 1H), 4.19–4.14 (m, 2H), 3.55–
3.51 (m, 2H), 3.09–3.03 (m, 1H), 2.89–2.86 (m, 1H), 2.53 (s,
3H), 2.31 (s, 3H), 1.96–1.88 (m, 2H), 1.29 (t, J=7.12 Hz,
3H); 13C NMR (100 MHz, CDCl3): d=150.3 (d, J=
9.63 Hz), 138.7, 135.5 (d, J=2.18 Hz), 130.4 (d, J=
13.17 Hz), 127.7, 126.7 (d, J=13.76 Hz), 124.3 (d, J=
7.25 Hz), 116.9 (d, J=7.43 Hz), 62.6 (d, J=6.88 Hz), 43.6 (d,
J=4.14 Hz), 31.4 (d, J=1.87 Hz), 28.1, 26.8, 23.8, 20.9, 20.6,
16.4 (d, J=5.80 Hz); 31P NMR (121 MHz, CDCl3, data for
31
the major isomer): d=22.51;
P NMR (121 MHz, CDCl3,
data for the minor isomer): d=9.75; IR (film): n=3477,
2882
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Adv. Synth. Catal. 2013, 355, 2873 – 2883

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