Modifying the chemistry of the phosphole dienic system by α-vinylation

Article abstract of DOI:10.1021/om500526u

1-Phenyl-2-vinyl-3,4-dimethylphosphole (4) was prepared from the corresponding 2-carboxaldehyde via a Wittig reaction. The reaction of its P-W(CO)₅ complex 5 with [PhP-W(CO)₅] selectively takes place at the vinyl double bond and give

Full text of DOI:10.1021/om500526u

Article
pubs.acs.org/Organometallics
Modifying the Chemistry of the Phosphole Dienic System
by α‑Vinylation
Kim Hong Ng, Yongxin Li, Rakesh Ganguly, and Francois Mathey*
Division of Chemistry & Biological Chemistry, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
S
* Supporting Information
ABSTRACT: 1-Phenyl-2-vinyl-3,4-dimethylphosphole (4) was
prepared from the corresponding 2-carboxaldehyde via a Wittig
reaction. The reaction of its P-W(CO)5 complex 5 with [PhP-
W(CO)5] selectively takes place at the vinyl double bond and
gives the corresponding phosphirane 6 as a mixture of two
diastereomers. The reaction of 4 with N-phenylmaleimide
involves the phosphole dienic system and gives the [4 + 2]
7-phosphanorbornene cycloadduct 7. The reaction of 5 with
dimethyl acetylenedicarboxylate either takes place at the
phosphole dienic system and leads to the vinyl phthalate 10
with loss of the phosphorus bridge or involves the double bonds of the vinyl and one phosphole group to give the [4 + 2] cycloadduct
9, which is oxidized in situ to give 11 with two epoxides and one ketone functionality. The products 6, 7, 9, and 11 were characterized
by X-ray crystal structure analysis.
n contrast to furans, thiophenes, and pyrroles, phospholes
I
are essentially nonaromatic1 as a result of the pyramidality of
the heteroatom. Their weak aromatic stabilization energy2
mainly results from a σ*/π hyperconjugation between the
exocyclic P−R bond and the dienic system. From a practical
standpoint, this means that the chemistry of phospholes is mainly
(but not exclusively) the superimposition of the classical
chemistry of the phosphorus lone pair and the chemistry of the
dienic system. On this basis, we wondered what could be the
influence of a vinyl substituent on the α position of the ring. We
expected a significant conjugation between the vinyl group and
the diene, leading to a sizable modification of the chemistry of the
phosphole ring. This is, indeed, the case to an unexpected extent,
as reported hereafter. Quite surprisingly, even though a few
α-alkenylphospholes have already been synthesized,3 they have
been studied as chromophores and the chemistry of their dienic
system has not been investigated.
Figure 1. Computed structure of 1-methyl-2-vinylphosphole (2). Main
distances (Å) and angles (deg): C1−P8 1.835, C4−P8 1.811, C9−P8
1.867, C1−C2 1.365, C2−C3 1.450, C3−C4 1.356, C1−C13 1.451,
C13−C15 1.341; C1−P8−C4 90.36, C1−P8−C9 103.44, P8−C1−C13
125.93.
RESULTS AND DISCUSSION
■
In order to have a preliminary insight into what could be expected,
we first performed comparative DFT calculations4 on 1-methyl-
phosphole (1) and 1-methyl-2-vinylphosphole (2) at the RB3LYP/
6-311+G(d,p) level. A similar computational study on
1-methylphosphole has already been published.5 The computed
structure of 2 (Figure 1) suggests a significant conjugation between
the vinyl group and the dienic system. Indeed, the vinyl group is
coplanar with the diene and the Cα−vinyl bond is somewhat
short at 1.451 Å and quite similar to the C−C intracyclic bond at
1.450 Å. Another criterion based on the alternation between C−
C and CC bonds also indicates that the diene is more deloca-
lized in 2 than in 1 (mean alternation 0.089 Å in 2 vs 0.103 Å in 1).
In parallel, the phosphorus atom in 2 is more pyramidal than in 1
(∑C−P−C 297.9° vs 301.0°), suggesting less interaction between
the heteroatom and the diene. A similar phenomenon had been
noticed in α-acetylenic phospholes.6 The picture is even more
demonstrative when looking at the frontier orbitals (Kohn−
Sham). The HOMO of 2 (Figure 2) is an antibonding
combination of the vinyl π bond with the diene HOMO. It lies
0.46 eV higher in energy than the HOMO of 1. Quite significantly,
Received: May 15, 2014
Published: August 7, 2014
© 2014 American Chemical Society
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Figure 3. X-ray crystal structure of 5 . Main distances (Å) and angles
(deg): C6−P1 1.806(7), C13−P1 1.794(8), C14−P1 1.834(8), C6−C9
1.359(11), C9−C11 1.449(12), C11−C13 1.340(11), C6−C7
1.459(11), C7−C8 1.317(13); C6−P1−C13 91.3(4), C6−P1−C14
105.1, P1−C6−C7 123.6(6).
Figure 2. Computed frontier orbitals (Kohn−Sham) of 1-methylphosp-
hole (1) and 1-methyl-2-vinylphosphole (2).
(δ(31P) −155.5 (6a), −156.9 ppm (6b)) are obtained in equal
amounts. The phosphirane 6a was characterized by X-ray crystal
structure analysis (Figure 4). The disruption of the conjugation
between the exocyclic α substituent and the phosphole dienic
system induces a lengthening of the phosphole−-substituent bond
and an increase of the alternation within the diene (0.138 Å).
The phosphole and phosphirane planes make an angle of 45°. The
classical rearrangement of 2-vinylphosphiranes into phospho-
lenes7,8 does not proceed with 6. Only decomposition products
were observed upon heating.
the energy of the lone pair orbital in 1 (HOMO-1) is practically
not affected in 2, confirming the very weak delocalization of the
lone pair over the ring.
Since the perturbation by the vinyl substituent mainly takes
place at the diene, we focused our experiments on the cyclo-
addition reactions. Our starting 2-vinylphosphole 4 was pre-
pared by reaction of methylenetriphenylphosphorane with the
aldehyde 3 (eq 1).
Our next experiments concerned the cycloaddition reactions
of N-phenylmaleimide with tervalent phospholes.9 We could
envisage two pathways, the first one involving the phosphole
dienic system and the second one involving the vinyl substituent
and the adjacent CC double bond. The first route is favored
by the locked cis conformation of the diene and the second one
by the better accessibility of the double bonds but disfavored by
the tendency of the diene to adopt the trans conformation. In
practice, the preliminary experiments conducted in a NMR tube
led to the endo adduct with the phosphole dienic system but,
unexpectedly, the product was oxidized at P, and the cyclo-
addition had taken place on the side of PO. It must be recalled
that the reaction of N-phenylmaleimide with 1-phenyl-3,4-
dimethylphosphole gives the nonoxidized adduct on the side of
the P−Ph substituent.9 We concluded that 4 itself is poorly
reactive and was first oxidized to the unstable phosphole oxide10
by atmospheric oxygen diffusing through the cap of the NMR
tube to then give the cycloadduct, hence the stereochemistry. It is
known that phosphole P-sulfides react by their PS faces, and
the phosphole oxides likely do the same. In order to confirm our
hypothesis, we ran the oxidation of 4 at room temperature in the
presence of N-phenylmaleimide and obtained the adduct 7 in
52% yield with only traces of the dimeric oxide of 4 (eq 3).
The structure of phosphole 4 was confirmed by X-ray crystal
structure analysis of its P-W(CO)5 complex 5 (Figure 3). The
similarity between the computed structure of 2 and the
experimental structure of 5 is obvious. The vinyl group is coplanar
with the diene and directed toward phosphorus in both cases. We
started our investigations on the reactivity of the unsaturated system
of 4 and 5 by the reaction of the terminal phosphinidene complex
[PhP-W(CO)5] with 5 in comparison with its classical [1 + 2]
cycloaddition with alkenes.7 The reaction exclusively takes place at
the vinyl substituent and proceeds in high yield (eq 2).
It is clear that the condensation takes place at the vinyl
double bond for steric reasons. The absence of steric hindrance
explains why the two possible phosphirane diastereomers
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Figure 4. X-ray crystal structure of 6a. Main distances (Å) and angles (deg): P1−C11 1.794(4), P1−C16 1.824(4), C11−C12 1.343(5), C12−C14
1.482(5), C14−C16 1.345(5), C16−C17 1.479(5), C17−C18 1.516(5), C17−P2 1.837(4), C18−P2 1.818(4); C11−P1−C16 91.21(17), C17−P2−
C18 49.02(17).
The molecular structure of 7 was established by X-ray single-
crystal analysis (Figure 5). The reaction of dimethyl acetylenedi-
carboxylate with 5 is more complex and proceeds very slowly. Two
main reaction pathways have been identified (eq 4).
precursors. The final product is the vinyl phthalate 10. The second
pathway (B) involves the vinyl group and the adjacent phosphole
double bond and leads to the [4 + 2] cycloadduct 9. The structure
of 9 is shown in Figure 6. The former dienic unit C15−C17−
C18−C20 is almost planar. The cyclohexadiene ring resulting
from the cycloaddition is bent around its C15−C20 axis with an
angle of 35.7°. The most puzzling observation is that a minute
amount of 9 is oxidized in situ to give the final product 11 with two
epoxidized double bonds and a ketonic group. Since the reaction
is carried out in a sealed tube, the oxygen cannot come from the
atmosphere. It probably comes from the excess dimethyl
acetylenedicarboxylate, the transfer being mediated by a tungsten
oxo species. Tungsten oxo species are known to be able to catalyze
the epoxidation of olefins.12 The structure of 11 was unambiguously
established by an X-ray crystal structure analysis (Figure 7). The two
epoxide rings are located on the P−phenyl side of the phosphole
ring. If we admit that a tungsten oxo species is responsible for the
epoxidation of the double bonds, it is clear that its steric bulk will
The first pathway (A) is the normal reaction pathway leading to
the 7-phosphanorbornadienes,11 which are used as phosphinidene
Figure 5. X-ray crystal structure of 7. Main distances (Å) and angles (deg): P1−C11 1.831(6), P1−C16 1.872(5), C9−C10 1.544(7), C9−C16
1.564(7), C10−C11 1.567(7), C16−C17 1.495(8), C17−C18 1.302(8); C11−P1−C16 83.5(3).
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Figure 6. X-ray crystal structure of 9. Main distances (Å) and angles (deg): P1−C12 1.798(3), P1−C17 1.809(3), C12−C13 1.330(5), C13−C15
1.537(4), C15−C17, 1.527(4), C17−C18 1.323(4), C18−C19 1.497(5), C19−C20 1.511(5), C20−C23 1.345(5), C23−C15 1.530(4); C12−P1−
C17 89.97(15).
Figure 7. X-ray crystal structure of 11. Main distances (Å) and angles (deg): P1−C12 1.810(10), P1−C15 1.820(10), C12−C13 1.494(14), C13−C16
1.543(13), C16−C15 1.527(13), C15−C25 1.330(14), C25−C24, 1.483(14), C24−O12 1.212(12), C24−C21 1.494(14), C21−C18 1.463(14),
C16−C18 1.510(13), C12−O6 1.449(12), C13−O6 1.455(13), C18−O9 1.420(12), C21−O9 1.434(12); C12−O6−C13 61.9(6), C18−O9−C21
61.7(6), C12−P1−C15 89.5(5).
chromatographic separations. The phosphinidene precursor was syn-
direct the epoxidation toward the less hindered side of the CC
thesized as described in the literature.11 NMR spectra were recorded on
bond: i.e., the side opposite to the W(CO)5 complexing group for
a JEOL ECA 400, a JEOL ECA 400 SL, or a Bruker BBFO2 400 MHz
the phosphole double bond and the side opposite to the C17 methyl
spectrometer. All spectra were recorded at 298 K. Proton decoupling
for the MeO2CCCCO2Me unit.
was applied for 13C and 31P spectra. HRMS were obtained on a Water
This preliminary work demonstrates that three pathways are
Q-Tof Premier MS. X-ray crystallographic analyses were performed
on a Bruker X8 APEX CCD diffractometer or a Bruker Kappa CCD
diffractometer.
possible for the cycloaddition reactions of 4 and 5, the chosen
pathway being dictated by the selected reagent. The selectivity is
surprisingly high, thus allowing us to use this chemistry for the
synthesis of new phosphorus ligands.
1-Phenyl-2-vinyl-3,4-dimethylphosphole (4). n-BuLi (1.4 mL,
1.6 M in hexane, 2.2 mmol) was added dropwise into an oven-dried two-
neck flask under N2 containing methyltriphenylphosphonium iodide
(0.8893, 2.2 mmol) suspended in THF (10 mL) at 0 °C. The reaction
mixture was stirred at room temperature for 15 min. Subsequently,
3,4-dimethyl-1-phenylphosphole-2-carboxaldehyde (3;13 0.4335 g,
2.0 mmol) dissolved in THF (3 mL) was added. The reaction mixture
was stirred overnight. The solvent was removed, and the crude product
EXPERIMENTAL SECTION
■
Oven-dried glasswares (105 °C) were used and cooled under a nitrogen
atmosphere. All reactions were carried out with distilled dry solvents and
under an N2 atmosphere. Silica gel (230−400 mesh) was used for the
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was purified using flash chromatography in degassed hexane. The phosphole
was obtained in 67% yield (0.3715 g).
(d, JC−P = 8.0 Hz, W(CO)5 cis CO), 197.06 (d, JC−P = 6.6 Hz,
W(CO)5 cis CO), 198.53 (d, JC−P = 31.0 Hz, W(CO)5 trans CO),
198.73 (d, JC−P = 19.0 Hz, W(CO)5 trans CO). Exact mass: calcd
C30H20O10P2W2Na, 992.9448; found, 992.9495.
31P NMR (CDCl3): δ −3.31 ppm. 1H NMR (CDCl3): δ 2.08−2.09
(m, 3H, Me), 2.10−2.11 (m, 3H, Me), 4.97 (d, JH−P = 10.6 Hz, 1H, 
CH2), 5.31 (d, JH−P = 17.2 Hz, 1H, CH2), 6.35 (d, JH−P = 39.7 Hz,
1H, CH−P), 6.70−6.81 (m, 1H, CH), 7.25−7.28 (m, 3H, Ph),
7.30−7.34 (m, 2H, Ph). 13C NMR (CDCl3): δ 13.78 (d, JC−P = 2.1 Hz,
Me), 18.35 (d, JC−P = 3.4 Hz, Me), 115.15 (d, JC−P = 12.3 Hz, CH2),
127.92 (d, JC−P = 1.1 Hz, P−CH), 128.68 (d, JC−P = 8.0 Hz, Ph), 129.29
(s, Ph), 131.22 (d, JC−P = 17.5 Hz, CH), 133.29 (d, JC−P = 11.8 Hz,
P−C(Ph)), 133.61 (d, JC−P = 19.4 Hz, Ph), 144.34 (s, P−C), 144.82
(d, JC−P = 10.2 Hz, C-Me), 150.38 (d, JC−P = 6.2 Hz, C-Me). Exact mass:
calcd C14H16P, 215.0990; found, 215.0972.
7-Phosphanorbornene Oxide 7. m-Chloroperoxybenzoic acid
(0.0814 g, 70% in H2O, 0.33 mmol) was dissolved in 5 mL of dichloro-
methane and dried over MgSO4. It was filtered into an addition funnel
attached to a two-neck flask containing 2-vinylphosphole 4 (0.0443 g,
0.33 mmol) and N-phenylmaleimide (0.0629 g, 0.36 mmol) dissolved
in 2 mL of dichloromethane. Then, m-CPBA solution was added drop-
wise into the reaction mixture at room temperature for 4 h. The crude
product was purified by chromatography with a 2/3 mixture of hexane
and ethyl acetate as the eluent. Oxide 7 was obtained (0.0692 g, 52%).
31P NMR (CH2Cl2): δ 74.4. 1H NMR (CD2Cl2): δ 1.65 (s, 3H, Me),
1.78 (s, 3H, Me), 3.54−3.57 (m, 1H, CH), 4.07−4.14 (m, 2H, CH),
5.52−5.55 (m, 1H, CH2), 5.68−5.73 (m, 1H, CH2), 6.14−6.24
1-Phenyl-2-vinyl-3,4-dimethylphosphole Pentacarbonyl-
tungsten Complex 5. 1-Phenyl-2-vinyl-3,4-dimethylphosphole (4;
0.135 g, 0.63 mmol) dissolved in THF (3 mL) was added to W(CO)5(THF)
(0.7 mmol) and the mixture stirred overnight at room temperature.
The solvent was removed under vacuum and the purification carried out
by flash chromatography using hexane (0.3380 g, 99%).
(m, 1H, CH), 7.06−7.08 (m, 2H, Ph), 7.38−7.58 (m, 8H, Ph). 13
C
NMR (CD2Cl2): δ 13.27 (d, JP−C = 3.0 Hz, CH3), 16.04 (d, JP−C = 4.4
Hz, CH3), 45.42 (d, JP−C = 12.4 Hz, CH), 48.46 (d, JP−C = 87.3 Hz,
P−CH), 48.7 (d, JP−C = 8.3 Hz, CH), 60.48 (d, JP−C = 66.0 Hz,
P−C),121.23 (d, JP−C = 10.1 Hz, CH2), 127.31 (s, Ph), 129.25
(d, JP−C = 8.9 Hz, P−C(Ph)), 129.28 (s, Ph), 129.42 (d, JP−C = 6.7 Hz,
1
31P NMR (CDCl3): δ 14.63 ppm (JP−W = 221.0 Hz). H NMR
(CDCl3): δ 2.18 (m, 6 H, Me), 5.16−5.23 (m, 2 H, CH2), 6.43 (d,
2JH−P = 36.8 Hz, 1H, CH−P), 6.71−6.83 (m, 1H, C−CH), 7.36−
7.51 (m, 5 H, Ph). 13C NMR (CDCl3): δ 13.77 (d, 3JC−P = 8.4 Hz, Me),
3
3
17.71 (d, JC−P = 10.5 Hz, Me), 118.97 (d, JC−P = 7.2 Hz, CH2),
128.65 (d, 2JC−P = 14.4 Hz, C−CH), 129.21 (d, JC−P = 10.5 Hz, Ph),
129.61 (d, JC−P = 38.6 Hz, P−C(Ph)), 130.95 (d, JC−P = 44.1 Hz, P−
CH), 131.04 (d, JC−P = 2.3 Hz, Ph), 132.48 (d, JC−P = 13.0 Hz, Ph),
142.40 (d, JC−P = 42.5 Hz, P−C), 145.90 (d, JC−P = 14.7 Hz, C-Me),
150.00 (d, JC−P = 7.5 Hz, C-Me), 196.61 (d, JC−P = 6.4 Hz, W(CO)5 cis
CO), 198.83 (d, JC−P = 19.3 Hz, W(CO)5 trans CO). Exact mass:
calcd C19H15O5PW, 538.0166; found, 538.0166.
Ph), 129.62 (d, JP−C = 6.1 Hz, CH), 129.81 (s, Ph), 130.44 (d, JP−C
=
8.8 Hz, C), 132.59 (s, Ph), 132.79 (d, JP−C = 8.0 Hz, Ph), 133.15
(d, JP−C = 2.7 Hz, Ph), 133.84 (d, JP−C = 10.8 Hz, C), 174.97 (d, JP−C
=
13.4 Hz, CO), 175.63 (d, JP−C = 14.1 Hz, CO). Exact mass: calcd
C24H23O3PN, 404.1416; found, 404.1434.
Reaction of 5 with Dimethyl Acetylenedicarboxylate.
Complex 5 (0.116 g, 0.22 mmol) was dissolved in 2 mL of toluene,
and dimethyl acetylenedicarboxylate (0.08 mL, 0.66 mmol) was added.
The reaction tube was sealed and heated at 90 °C for 3 days. Two new
Phosphirane Complexes 6a,b. Complex 5 (0.199 g, 0.37 mmol),
CuCl (0.019 g, 0.19 mmol), and 7-phenyl-7-phosphanorbornadiene
tungsten complex11 (0.726 g, 1.1 mmol) were dissolved in toluene.
The mixture was heated to 55 °C for 1 day in a sealed tube. Solvent
was removed, followed by purification by chromatography with a
1/4 mixture of dichloromethane and hexane as the eluent. Isomer A
(0.074 g, 41%) was eluted before isomer B (0.072 g, 40%).
peaks were observed in the crude reaction mixture at 2.87 ppm (JP−W
=
233.5 Hz) and 21.0 ppm (JP−W = 218.9 Hz) with the presence of starting
material at 14 ppm. Purification was performed by gradient
chromatography, with a 1/4 mixture of dichloromethane and hexane
as the eluent to 100% dichloromethane. A mixture of products 9 and 11
was first eluted, followed by compound 10 (0.0175 g of colorless oil,
43.8%). Compounds 9 and 11 were separated by PTLC, with a 4/1
mixture of dichloromethane and hexane as the eluent. A 0.013 g portion
of pale yellow solid 9 was obtained (12%), while compound 11 was
recovered as a yellow oil (0.0029 g, 2%).
Isomer A. 31P NMR (CDCl3): δ −155.46 (d, JP−P = 18 Hz, JP−W
=
268.7 Hz), 22.11 (d, JP−P = 18 Hz, JP−W = 216.7 Hz). 1H NMR
(CD2Cl2): δ 1.21−1.27 (m, 1H, CH2), 2.24−2.30 (m, 1H, CH2), 2.28
(s, 3H, CH3), 2.45 (s, 3H, CH3), 2.74 (m, 1H, CH), 6.65 (d, JP−H = 36.0
Hz, 1H, CH), 7.42−7.46 (m, 6H, Ph), 7.51−7.56 (m, 2H, Ph), 7.62−
7.67 (m, 2H, Ph). 13C NMR (CD2Cl2): δ 15.37 (d, JP−C = 8.8 Hz, CH3),
15.97 (dd, 1JP−C = 11.0 Hz, 3JP−C = 4.8 Hz, CH2), 18.22 (d, JP−C = 10.5
Hz, CH3), 26.49 (pseudo t, JP−C = 34.5 Hz, CH), 128.76 (d, JP−C = 37.0
Hz, P−C(Ph)), 129.55 (d, JP−C = 9.9 Hz, Ph), 129.76 (d, JP−C = 10.5 Hz,
Ph), 130.76 (d, JP−C = 49.1 Hz, CH), 131.58 (d, JP−C = 1.9 Hz, Ph),
131.79 (d, JP−C = 12.0 Hz, Ph), 132.43 (d, JP−C = 2.4 Hz, Ph), 134.01
(d, JP−C = 13.7 Hz, Ph), 136.13 (d, JP−C = 29.3 Hz, P−C(Ph)), 140.78
(d, JP−C = 39.5 Hz, P−C), 150.09 (dd, JP−C = 5.7 Hz, JP−C = 17.3 Hz,
C−Me), 152.71 (dd, JP−C = 2.5 Hz, JP−C = 7.9 Hz C−Me), 195.97
(d, JC−P = 8.1 Hz, W(CO)5 cis CO), 197.17 (d, JC−P = 6.3 Hz,
W(CO)5 cis CO), 197.78 (d, JC−P = 31.9 Hz, W(CO)5 trans CO),
198.86 (d, JC−P = 19.0 Hz, W(CO)5 trans CO). Exact mass: calcd
C30H20O10P2W2Na, 992.9448; found, 992.9495.
1
Compound 9. 31P NMR (CD2Cl2): δ 2.73 (JP−W = 234.1 Hz). H
NMR (CD2Cl2): δ 1.53 (s, 3H, Me), 2.04 (s, 3H, Me), 3.07 (m,1H,
CH2), 3.33−3.41 (m, 1H, CH2), 3.70 (s, 3H, OMe), 3.82 (s, 3H, OMe),
2
6.04 (d, JH−P = 33.6 Hz, 1H, P−CH), 6.28−6.32 (m, 1H, CH),
7.38−7.58 (m, 5H, Ph). 13C NMR (CD2Cl2): δ 17.27 (d, JC−P = 10.0 Hz,
Me), 27.11 (s, Me), 28.97 (d, JC−P = 10.1 Hz, CH2), 52.84 (s, OMe),
52.95 (s, OMe), 55.75 (d, JC−P = 13.5 Hz, C−Me), 125.24 (d, JC−P = 46.8
Hz, P−CH), 128.54 (s, C), 129.30 (d, JC−P = 10.1 Hz, Ph), 131.11
(d, JC−P = 2.2 Hz, Ph), 132.39 (d, JC−P = 13.7 Hz, Ph), 133.84 (d, JC−P
=
12.9 Hz, CH), 137.72 (d, JC−P = 34.1 Hz, P−C(Ph)), 147.42
(d, JC−P = 41.7 Hz, P−C), 148.97 (s, C), 156.63 (s, C), 165.80
(s, CO2Me), 169.21 (s, CO2Me), 197.44 (d, JC−P = 7.0 Hz, W(CO)5 cis
CO), 200.03 (d, JC−P = 20.1 Hz, W(CO)5 trans CO). Exact mass:
calcd C25H21O9PW, 680.0433; found, 680.0413.
Isomer B. 31P NMR (CD2Cl2): δ −156.94 (d, JP−P = 5.7 Hz, JP−W
=
1
261.1 Hz), 20.29 (d, JP−P = 5.7 Hz, JP−W = 216.7 Hz). H NMR
(CD2Cl2): δ 1.86−1.93 (m, 2H, CH2), 2.17 (d, JP−H = 0.9 Hz, 3H, CH3),
2.29 (d, JP−H = 1.0 Hz, 3H, CH3), 2.66 (pseudo t, JP−H = 19.6 Hz, 1H,
CH), 6.38 (d, JP−H = 36.0 Hz, 1H, CH), 6.80−6.85 (m, 2H, Ph),
7.01−7.15 (m, 6H, Ph), 7.24−7.34 (m, 2H, Ph). 13C NMR (CD2Cl2): δ
Compound 11. 31P NMR (CD2Cl2): δ 21.39. Exact mass: calcd
C25H19O12PW, 726.0124; found, 726.0128.
Compound 10. 1H NMR (CDCl3): δ 2.24 (s, 3H, Me), 2.32 (s, 3H,
Me), 3.85 (s, 3H, OMe), 3.87 (s, 3H, OMe), 5.33 (dd, J(H−H) = 18.0 Hz,
14.93−15.07 (m, CH2), 15.44 (d, JP−C = 8.9 Hz, CH3), 18.04 (d, JP−C
=
10.5 Hz, CH3), 27.71−28.07 (m, CH), 127.46 (d, JP−C = 37.2 Hz, P−
C(Ph)), 129.52 (d, JP−C = 10.2 Hz, Ph), 129.74 (d, JP−C = 10.4 Hz, Ph),
130.52 (d, JP−C = 47.1 Hz, CH), 130.83 (d, JP−C = 1.9 Hz, Ph), 131.20
(d, JP−C = 30.5 Hz, P−C(Ph)), 131.42 (d, JP−C = 2.3 Hz, Ph), 132.27
(d, JP−C = 12.3 Hz, Ph), 133.23 (d, JP−C = 13.6 Hz, Ph), 139.99
(dd, JP−C = 6.8 Hz, JP−C = 38.8 Hz, P−C), 148.79 (dd, JP−C = 4.7 Hz,
JP−C = 17.1 Hz, C−Me), 151.76 (d, JP−C = 8.0 Hz, C−Me), 196.17
J
(H−H) = 1.6 Hz, 1H, CH2), 5.49 (dd, J(H−H) = 12.8 Hz, J(H−H) = 1.6 Hz,
1H, CH2), 6.70−6.78 (m, 1H, CH), 7.73 (s, 1H, Ph). 13C NMR
(CD2Cl2): δ 16.96 (Me), 20.65 (Me), 52.48 (OMe), 52.51 (OMe),
121.00 (CH2), 124.79 (Ph), 130.28 (C−H(Ph)), 133.08 (Ph), 134.26
(CH), 136.78 (Ph), 138.03 (Ph), 140.45 (Ph), 166.42 (CO2Me), 170.09
(CO2Me). Exact mass: calcd C14H17O4, 249.1127; found, 249.1141.
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dx.doi.org/10.1021/om500526u | Organometallics 2014, 33, 4245−4250

Organometallics
Article
ASSOCIATED CONTENT
* Supporting Information
■
S
Figures, tables, and CIF and xyz files giving X-ray crystal structure
analyses of compounds 5, 6a, 7, 9, and 11, all computed molecule
2 Cartesian coordinates in a format for convenient visualization,
and NMR spectra. This material is available free of charge via the
Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*E-mail for F.M.: fmathey@ntu.edu.sg.
■
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
The authors thank the Nanyang Technological University in
Singapore for the financial support of this work.
■
REFERENCES
■
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