Nickel-catalyzed decarboxylative C-P cross-coupling of alkenyl acids with P(O)H compounds

Article abstract of DOI:10.1021/jo501321m

The first nickel-catalyzed decarboxylative C-P coupling of a wide range of alkenyl acids with various P(O)H compounds, especially for H-phosphonates, has been developed, affording a versatile and efficient tool for the preparation of valuable (E)-1-alkeny

Full text of DOI:10.1021/jo501321m

Article
pubs.acs.org/joc
Nickel-Catalyzed Decarboxylative C−P Cross-Coupling of Alkenyl
Acids with P(O)H Compounds
Yile Wu,† Liu Liu,† Kaili Yan,† Pengxiang Xu,† Yuxing Gao,*,† and Yufen Zhao†,‡
†Department of Chemistry and Key Laboratory for Chemical Biology of Fujian Province, College of Chemistry and Chemical
Engineering, Xiamen University, Xiamen 361005, Fujian, China
‡Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry,
Tsinghua University, Beijing 100084, China
S
* Supporting Information
ABSTRACT: The first nickel-catalyzed decarboxylative C−P
coupling of a wide range of alkenyl acids with various P(O)H
compounds, especially for H-phosphonates, has been
developed, affording a versatile and efficient tool for the
preparation of valuable (E)-1-alkenylphosphonates, (E)-1-
alkenylphosphinate oxides, and (E)-1-alkenylphosphine oxides
with high stereoselectivity and broad substrate applicability. DFT calculation revealed that the phosphine ligand exhibits better
catalytic performance than the nitrogen ligand in the reductive elimination step owing to the stronger nucleophilicity and larger
size.
alkenyl acids as the coupling substrates via decarboxylation is
considerably rare, and there is only one reported example. In
2011, the first Cu-mediated decarboxylative coupling of alkenyl
acids with secondary phosphine oxides have been reported.12
This protocol first exemplified that alkenyl acids are potential
coupling partners for C−P bond constuction, but this reaction
did not work well for the dialkyl H-phosphonate, such as
diisoproyl H-phosphonate giving the product in 50% yield.
Moreover, alkenyl acids are stable, inexpensive, readily
obtainable, and structurally diverse, only CO2 is generated
instead of metal halides, and the configuration of alkenyl acids
may ensure high regio- and stereoselectivity. Thus, using
alkenyl acids as coupling substrates, the development of
efficient and versatile methods to access various alkenylphos-
phorus compounds via transition-metal-catalyzed decarboxyla-
tive coupling is still desirable and attractive in synthetic
chemistry.
Although decarboxylative coupling reactions have emerged as
fascinating and powerful approaches for regioselective C−C
bond formation over the years,9 the known decarboxylation for
the C−P bond formation is scarce.12,13 Moreover, the
commonly employed metal catalysts are limited to the classical
Pd, Cu, and Ag metals,14 and little attention has been paid to
use of the metal nickel as a decarboxylative catalyst.15 Herein,
we report the first versatile Ni-catalyzed decarboxylative cross-
coupling of various alkenyl acids with P(O)H compounds,
especially H-phosphonates, leading to (E)-1-alkenylphospho-
nates, (E)-1-alkenylphosphinate oxides, and (E)-1-alkenylphos-
phine oxides in moderate to excellent yields with high
stereoselectivity. To the best of our knowledge, the nickel-
INTRODUCTION
■
Transition-metal-catalyzed cross-coupling reactions for car-
bon−phosphorus bond formation have become the most
straightforward and powerful ways for the preparation of
organophosphorus compounds in the past two decades, which
have widespread applications in biological, pharmaceutical,
material, and catalytic sciences.1 Among them, alkenylphos-
phorus compounds are an important class of carbon−
phosphorus bond-containing valuable chemicals, which are
extensively used as biologically active molecules in medicinal
chemistry2 and as additives or flame-retardants in polymer
sciences.3 Furthermore, they can also serve as useful precursors
for asymmetric addition reactions.4 Efficient methods for the
synthesis of alkenylphosphorus compounds mainly include
Heck-type coupling of vinylphosphonates with various aryl
partners,5 olefin cross-metathesis,6 cross-coupling of P(O)H
with vinyl halides,7 and addition of P(O)H to alkynes.8
However, most of the existing methods are still plagued with
problems including lack of stereoselectivity,8 limited substrate
scope,5,6 relatively drastic conditions not compatible with
sensitive functional groups,7 unsatisfactory yields,5a,7a,b the
occasional need to use strong bases,7b,c and the need for air-
sensitive5 or noble metal catalysts.6,8a,b,d In view of these
challenges, there is still a strong need to develop more
convenient and efficient protocols for the synthesis of
alkenylphosphorus compounds with high stereoselectivity
from readily available starting materials.
On the other hand, alkenyl acids are one of the most
extensively versatile building blocks in transition-metal-
catalyzed decarboxylative cross-couplings for the effective
construction of C−C,9 C−N,10 and C−S11 bonds due to
their commercial availability and structural diversity. Never-
theless, in stark contrast, C−P bond-forming reaction using
Received: June 13, 2014
© XXXX American Chemical Society
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catalyzed decarboxylative coupling of alkenyl acids with P(O)H
compounds has never been developed. The protocol reported
herein may be used as an efficient complement for the classical
Pd-, Cu-, or Ag-catalyzed decarboxylation.
Ni(dppf)Cl2 was found to be the best choice and promoted the
yield up to 90% (entry 9). Notably, the known Cu-catalyzed
decarboxylation of 1a with 2a only gave 50% yield,12 illustrating
that nickel catalysts afforded higher reaction efficiency than
copper salts using H-phosphonates as substrates. A screening of
the additives disclosed Ag2O as the most favored one to push
the reaction forward, affording the desired product 3a in 90%
(entries 9, 12, and 13). The Ag2O loading was also evaluated,
and using 1 equiv of Ag2O led to a significant yield decrease
(35%, entry 14). A subsequent survey on the role of solvents
revealed that DMSO was the optimal candidate (entries 15−
17). Decreasing the reaction temperature to 100 °C resulted in
a lower yield of 76%, and no distinct change was detected by
raising the reaction temperature (entry 18). Increasing the
loading of ligand dppf did not improve the yield (entry 19).
When the reaction time decreased to 6 h, a lower yield of 85%
was obtained (entry 20). Note that the decarboxylative
coupling did not proceed smoothly in the absence of either
Ni(dppf)Cl2 or Ag2O, disclosing that Ni(dppf)Cl2 and Ag2O
were critical to achieve a high yield.
RESULTS AND DISCUSSION
■
Initially, we optimized the catalytic conditions for the
decarboxylative coupling of cinnamic acid 1a with diisopropyl
phosphonate 2a in the presence of Ni(OAc)2 (5 mol %), Ag2O
(2 equiv), 1,1′-bis(diphenylphosphino)ferrocene (dppf, 7.5 mol
%), and DMSO (5 mL) under a nitrogen atmosphere.
Gratifyingly, we observed that a 36% yield of the desired
product 3a was obtained after 12 h at 120 °C (Table 1, entry
a
Table 1. Optimization of the Reaction Conditions
b
c
entry
catalyst
ligand
additive
solvent
yield (%)
With the optimized reaction conditions in hand, the scope
and generality of the method were examined by varying the
structures of the alkenyl acids. As shown in Table 2, various
valuable (E)-1-alkenylphosphonates can be conveniently and
efficiently obtained in moderate to high yields with high
stereoselectivity by this novel Ni-catalyzed decarboxylative
coupling reaction, indicating that this method is general and
practically useful. Besides the fact that no traces of regio- or
stereoisomers were detected by in situ 31P NMR and 1H NMR
analysis in all these decarboxylative couplings, the results
demonstrated that this novel Ni-catalyzed decarboxylation
exhibited high stereoselectivities with E-isomers. In general,
both electron-rich and electron-deficient aromatic alkenyl acids
were suitable for this method, and a wide range of functional
groups, such as methyl, fluoro, chloro, methoxy, trifluorometh-
yl, carboxyl, nitro, dimethylamino, and phenyl groups were all
tolerated under the reaction conditions (3a−o). Substituents at
the ortho position do not affect the reactivity (entries 4 and 8).
Interestingly, (E)-2-methyl-3-phenylacrylic acid (1e) could also
be used in the reaction to afford the expected product 3e in
50% yield with high stereoselectivity (entry 5). Notably, the
alkenyl acid moiety represented a higher chemoselectivity over
the fluorine and chlorine as leaving groups, demonstrating the
potential of this new method to allow access to highly
functionalized targets by stepwise coupling (3f−h). Generally,
electron-rich substrates showed better reactivity and higher
yields than electron-poor ones. For example, cinnamic acid
substrates having strong electron-withdrawing groups such as
nitro and pentafluoro on the phenyl ring only gave moderate
yields of 57% and 53%, respectively (entries 13 and 17).
Notably, heteroaromatic alkenyl acids such as 1r could also be
used as suitable substrates to give the corresponding product in
moderate yield (entry 18). Unfortunately, aliphatic alkenyl
acids such as sorbic acid and crotonic acid only gave a trace
amount of the desired products. It is noticeable that (Z)-
cinnamic acid as the coupling substrate only gave an 87% yield
of diisopropyl (E)-styrylphosphonate 3a without the generation
of diisopropyl (Z)-styrylphosphonate under the similar reaction
conditions (entry 19), probably since Z-E tautomerism
occurred in the reaction process under the high-temperature
conditions and the E-isomer is thermodynamically more stable
than the Z-isomer.
1
Ni(OAc)2
Ni(acac)2
NiBr2
dppf
dppf
dppf
dppf
Phen
bpy
Ag2O
Ag2O
Ag2O
Ag2O
Ag2O
Ag2O
Ag2O
Ag2O
Ag2O
Ag2O
Ag2O
Ag2CO3
AgOAc
Ag2O
Ag2O
Ag2O
Ag2O
Ag2O
Ag2O
Ag2O
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
NMP
36
27
2
3
54
4
NiCl2
64
5
NiCl2
8
6
NiCl2
26
7
NiCl2
dppp
47
8
NiCl2
20
9
Ni(dppf)Cl2
Ni(dppp)Cl2
Ni(PPh3)Cl2
Ni(dppf)Cl2
Ni(dppf)Cl2
Ni(dppf)Cl2
Ni(dppf)Cl2
Ni(dppf)Cl2
Ni(dppf)Cl2
Ni(dppf)Cl2
Ni(dppf)Cl2
Ni(dppf)Cl2
90
50
10
11
12
13
14
15
16
17
18
19
20
40
trace
36
d
35
79
86
30
DMF
toluene
DMSO
DMSO
DMSO
e
76
dppf
89
f
85
a
Reaction conditions: 1a (0.6 mmol), 2a (0.5 mmol), catalyst (0.025
mmol), ligand (0.03 mmol), additive (1 mmol), solvent (5 mL), 120
°C, 12 h, under nitrogen. Using anhydrous metal salts as catalysts.
Yields are based on 2a. Using 0.5 mmol of Ag2O. At 100 °C. For 6
b
c
d
e
f
h.
1). Encouraged by this promising result, the effect of catalysts,
ligands, solvents, additives, and temperature on reaction yield
was further evaluated, and some representative results are
shown in Table 1. Various nickel salts including Ni(OAc)2,
NiBr2, NiCl2, and Ni(acac)2 were investigated, with the finding
that NiCl2 was the optimal choice for the coupling reaction
(entries 1−4). Among the various ligands screened, dppf
turned out to be the best ligand and enhanced the
decarboxylative coupling to produce 3a in 64% yield (entry
4). Other ligands and the corresponding yields were as follows:
1,10-phenanthroline (Phen, 8%), 2,2′-bipyridine (bpy, 28%),
and dppp (47%) (entries 5−7). Without the ligand, a lower
yield of 3a was observed under similar reaction conditions
(entry 8). To advance the process further, NiCl2 coordination
complexes such as Ni(dppf)Cl2, Ni(dppp)Cl2, and Ni-
(PPh3)2Cl2 were also evaluated (entries 9−11). Delightedly,
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a
Table 2. Ni-Catalyzed Decarboxylative Coupling of Alkenyl Acids with Diisopropyl Phosphonates
a
Reaction conditions: 1a (0.6 mmol), 2a (0.5 mmol), Ni(dppp)Cl2 (0.025 mmol), Ag2O (1 mmol), DMSO (5 mL), 120 °C, 12 h, under nitrogen.
b
1
Yields are based on 2a. No regio- or stereoisomers were detected by 31P NMR and H NMR analysis of crude reaction mixtures.
In regard to the H-phosphonates, in addition to 2a, diethyl
(3v−x) and (E)-1-alkenylphosphine oxides (3y, 3z, and 3jf)
products in good to high yields. Obviously, this method with
broad substrate applicability and high stereoselectivity provided
a general and powerful tool for the preparation of various
valuable (E)- alkenylphosphorus compounds.
Inspired by the above results, we next briefly turned our
attention to extend this method to the synthesis of alkynyl
phosphonates starting from alkynyl acids. However, using
(2b), and dibutyl (2c) phosphonates, as well as 5,5-dimethyl-
1,3,2-dioxaphosphinane 2-oxide (2d), all could be used as the
substrates, affording the desired products 3s−u in 91%, 67%,
and 69% yields, respectively (Table 3, entries 1−3). In addition,
we note that ethyl phenylphosphinate (2e) and diphenylphos-
phine oxide (2f) were also compatible with this reaction, thus
affording the corresponding (E)-1-alkenylphosphinate oxides
C
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a
Table 3. Ni-Catalyzed Decarboxylative Coupling of Alkenyl Acids with P(O)H Compounds
a
Reaction conditions: 1 (0.6 mmol), 2 (0.5 mmol), Ni(dppp)Cl2 (0.025 mmol), Ag2O (1 mmol), DMSO (5 mL), 120 °C, 12 h, under nitrogen.
b
1
Yields are based on 2. No regio- or stereoisomers was detected by 31P NMR and H NMR analysis of crude reaction mixtures.
a
Table 4. Ni-Catalyzed Decarboxylative Coupling of Alkynyl Acids with Diisopropyl Phosphonates
a
Reaction conditions: 4 (0.3 mmol), 2a (0.25 mmol), Ni(NO3)2·6H2O (0.025 mmol), Ag2CO3 (0.5 mmol), DMSO (2 mL), 100 °C, 12 h, under
b
nitrogen. Yields are based on 2a.
Ni(dppf)Cl2 as catalyst, the decarboxylative coupling of 3-
phenylpropiolic acid 4a with 2a only gave a trace amount of the
desired product 5a under the above optimized reaction
conditions. After investigation of the reaction conditions, we
discovered that the Ni(NO3)2·6H2O/Ag2CO3 catalysis system
was the best choice and afforded product 5a in 45% yield
(Table 4, entry 1). In addition to 4a, alkynyl acid substrates
with methoxy and trifluoromethyl groups gave the correspond-
ing coupling products 5b and 5c in low yields of 36% and 40%,
respectively (Table 4, entries 2 and 3).
Transition-metal-catalyzed decarboxylative coupling reac-
tions for the formation of the C−C bond have been extensively
studied both experimentally and theoretically.16 The results
showed the catalytic cycle underwent different steps depending
on substrates.17 To understand the mechanism, radical traps
BHT (2,6-di-tert-butyl-4-methylphenol) and TEMPO (2,2,6,6-
tetramethylpiperidin-1-oxyl) were added to the reaction system
under the optimized reaction conditions, respectively, and a
significant yield decrease was not observed (90% and 80%
yields, respectively), indicating that this coupling might not be a
radical reaction. On the basis of their findings and our
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Figure 1. Free energy profile for the decarboxylative step. The energies are given in kcal/mol.
experiences in organophosphorus chemistry,7d,18 we proposed a
Scheme 2. Reaction of Cinnamic Acid with (EtO)2P(O)Ag
mechanism for the intermolecular decarboxylative coupling
reactions of alkenyl acids with P(O)H compounds (Figure 1
and Scheme 1). Moreover, density functional theory (DFT)
Scheme 1. Proposed Mechanism
the second ligand exchange takes place when AgP(O)(OR)2
reacts with IN1, leading to a tetracoordinated Ni(II) complex
IN2.21,22 Subsequently, an η2 Ni (0) complex IN3 is formed
through the reductive elimination (RE) step. Notably, a silver
mirror was observed after the reaction was completed. Hence,
the catalyst Ni(dppf)X2 is regenerated by a Ag(I)-mediated
oxidation.23
It is very interesting to note that nickel catalyst bearing
phosphine ligands exhibited an excellent catalytic performance,
whereas nitrogen ligands gave only poor yields (Table 1). To
understand the origin of the different reactivity between
phosphine and nitrogen ligands, the calculations were also
carried out using 2,2′-bipyridine as the ligand (Figure 2).
Surprisingly, the activation barriers of the RE step are much
different. When Ni(dppf)Cl2 was chosen as model catalyst, the
free energy barrier of the RE step is 16.3 kcal/mol lower than
that of Ni(bpy)Cl2 as catalyst, which can be mainly attributed
to electronic effect of the ancillary ligand in the corresponding
transition state.24 For instance, in the study of (R3P)2PdMe2
species,25 Ariafard and Yates suggested that for stabilizing the
transition state of RE step the suitable ligands should be
forming strong bonds with the Pd center and large ligands will
lead to a destabilization of the reactant (R3P)2PdMe2
complexes but not the transition structures. On the basis of
their findings, the phosphine ligand should be a better
candidate for the RE step since it is more nucleophilic than
the nitrogen ligand.26 Moreover, the C−P bond length (2.056
Å) in TS1 is much longer than that (1.971 Å) in TS1′, clearly
demonstrating that IN2′ requires more energy to reach TS1′.
calculations were carried out to investigate the key steps. The
model substrates cinnamic acid, dimethyl phosphonate, Ag2O,
and Ni(dppf)Cl2 were chosen. Relative free energies in solution
(DMSO) are employed to analyze the reaction mechanism.
A silver-involved decarboxylative process has been proposed
by several groups.19 Initially, cinnamic acid (INA) reacted with
Ag2O to generate cinnamoyloxy silver (INB, −25.3 kcal/mol)
with the loss of AgOH (Figure 1). Note that the bond length of
C1−C2 (1.491 Å) in INB is longer than that in INA (1.475 Å),
indicating the C1−C2 bond is preactivated by silver cation.
From INB, a four-membered transition state TSA (activation
energy is 29.8 kcal/mol) is identified, where the O−C2−O
angle is increased to 144.6°. Then styrylsilver (INC, −17.0
kcal/mol) is formed along with the removal of CO2.
The approach of INC toward catalyst Ni(dppf)X2 (X = Cl,
OH, or −COO) produces an intermediate IN1 via a ligand-
exchange process. Note that dialkyl phosphonate could react
with AgOH to form AgP(O)(OR)2,20 and this process is
computed to be exothermic (ΔG = −18.5 kcal/mol, R = Me).
We believe that AgP(O)(OMe)2 instead of dimethyl
phosphonate may be involved in the next step. To support
our hypothesis, a mixture of 1a (0.48 mmol), (EtO)2P(O)Ag
(2A) (0.4 mmol), Ag2O (0.4 mmol), and Ni(dppf)Cl2 (0.02
mmol) in DMSO was treated at 120 °C for 12 h, providing the
C−P coupling product 3s in 70% yield (Scheme 2). However, a
mixture of 1a, 2A, and Ni(dppf)Cl2 without Ag2O did not give
the corresponding product 3s under similar conditions. Thus,
CONCLUSION
■
In summary, we have successfully developed the first versatile
and efficient Ni-catalyzed decarboxylative C−P coupling
reaction of various alkenyl acids with a wide range of P(O)H
compounds, especially for H-phosphonates, affording valuable
(E)-1-alkenylphosphonates, (E)-1-alkenylphosphinate oxides,
and (E)-1-alkenylphosphine oxides. Importantly, the present
method exhibits good compatibility with various types of P-
nucleophiles including H-phosphonates, H-phosphinate esters,
and easily oxidized H-phosphine oxides and allows them to be
coupled efficiently. In addition, using commercially available,
cheap and stable alkenyl acids as the coupling partners only
generating CO2 instead of environmentally unfriendly halides,
the remarkable functional group tolerance, the high stereo-
E
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Figure 2. Free energy profile for the reductive elimination step using dppf (a) and bpy (b), respectively. The energies are given in kcal/mol.
free energies reported herein correspond to the reference state of 1
mol/L, 298 K. Structures were visualized by the CYLview program.36
selectivity, and moderate to excellent yield mean that this
effective method will be attractive for academia and industry. It
is foreseeable that this novel Ni-catalyzed decarboxylative C−P
coupling system will extend to the nickel-catalyzed decarbox-
ylative cross-coupling for the formation of carbon−carbon and
carbon−heteroatom bonds in the future. DFT calculation
showed that the phosphine ligand exhibits better catalytic
performance than the nitrogen ligand because of the stronger
nucleophilicity and larger size. Detailed mechanistic inves-
tigations and synthetic applications for this reaction are
currently ongoing.
EXPERIMENTAL SECTION
■
Unless otherwise stated, all reagents were purchased from commercial
sources and used without further purification. All the reactions were
carried out using standard Schlenk techniques. Column chromatog-
raphy was carried out on silica gel of 300−400 mesh size. 31P, 1H, and
13C{1H} NMR spectra were measured on 400 or 500 MHz
spectrometers. 1H NMR and 13C{1H} NMR were recorded using
tetramethylsilane as the internal standard. 31P NMR was recorded
using 85% H3PO4 as external standard for 31P NMR. Data are
represented as follows: chemical shift, multiplicity (br s = broad
singlet, s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet),
coupling constants in hertz (Hz), integration. All new compounds
were further characterized by elemental analysis.
COMPUTATIONAL METHODS
■
Geometry optimizations for all species studied in this work have been
performed via the Gaussian 03 program.27 A hybrid Becke3LYP
(B3LYP) method,28 which was widely adopted in the previous papers
on mechanistic studies of Ni-catalyzed reactions, was used.7d,29 The
D95v(d) basis set was chosen to describe the C, H, N, and O atoms,30
and the effective core potentials of Hay and Wadt with a valence
double-ζ basis set (LanL2DZ) were used for the Ni, Ag, Fe, and P
atoms.31 Polarization functions were also added: Ni(ζf) = 3.130,
Ag(ζf) = 1.611, Fe(ζf) = 2.462, and P(ζd) = 0.387.32 For each
optimized species, vibrational frequency analyses have been carried out
to identify all of the stationary points as minima (zero imaginary
frequency) or transition states (one imaginary frequency) on the
potential energy surfaces. Intrinsic reaction coordinate (IRC)
calculations were also performed to confirm that the transition states
indeed connect two corresponding minima. Single-point calculations
in solution (DMSO) have been calculated (IEF-PCM method with the
Bondi radii)33 with the same method using the SDD34 pseudopotential
for the metal center and the extended 6-311+G(2d,p)35 basis set for
the other atoms using gas-phase geometry. A similar treatment was
also used in several recent theoretical studies.23,29 The free energy
correction from frequency calculation was added to the single-point
energy to obtain the free energy in solution. All of the solution-phase
General Procedure for Ni-Catalyzed Decarboxylative C−P
Cross-Coupling of Alkenyl Acids with P(O)H Compounds.
Alkenyl acids (0.6 mmol, 1.2 equiv), H-phosphonates (0.5 mmol, 1
equiv), Ni(dppf)Cl2 (0.025 mmol, 0.05 equiv, 17.1 mg), and Ag2O (1
mmol, 2 equiv, 231.7 mg) were dissolved in 5 mL of DMSO and
stirred at 120 °C for 12 h under an atmosphere of nitrogen. The
resulting mixture was concentrated, and the residue was purified by
silica gel column chromatography using a mixture of petroleum ether
and ethyl acetate as eluent to give the alkenylphosphorus compounds.
Spectral Data of the Compounds. Diisopropyl (E)-Styryl-
phosphonate (3a, CAS 78463-00-0). Colorless oil. 121 mg, 90%
yield. 1H NMR (500 MHz, CDCl3): δ 7.53−7.45 (m, 3H), 7.40−7.36
(m, 3H), 6.31−6.22 (t, J = 17.5 Hz, 1H), 4.76−4.69 (m, 2H), 1.38−
1.36 (d, J = 6.2 Hz, 6H), 1.33−1.32 (d, J = 6.2 Hz, 6H). 13C{1H}
NMR (125 MHz, CDCl3): δ 146.8 (d, JC−P = 6.7 Hz), 134.1 (d, JC−P
=
22.8 Hz), 129.0, 127.8, 126.6, 114.7 (d, JC−P = 191.5 Hz), 69.5 (d, JC−P
= 5.9 Hz), 23.1 (d, JC−P = 4.5 Hz), 23.0 (d, JC−P = 4.5 Hz). 31P NMR
(CDCl3, 203 MHz): δ 17.3. ESI-MS: m/z = 269 [M + H]+. Anal.
Calcd for C14H21O3P: C, 62.67; H, 7.89. Found: C, 62.45; H, 7.67.
Diisopropyl (E)-(4-Methylstyryl)phosphonate (3b, New Com-
1
pound). Light yellow oil; 120 mg, 85% yield. H NMR (400 MHz,
F
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CDCl3): δ 7.50−7.38 (m, 3H), 7.19−7.17 (m, 2H), 6.25−6.16 (t, J =
17.6 Hz, 1H), 4.74−4.66 (m, 2H), 2.36 (s, 3H), 1.37−1.36 (d, J = 6.2
Hz, 6H), 1.32−1.31 (d, J = 6.2 Hz, 6H). 13C{1H} NMR (100 MHz,
CDCl3): δ 146.7 (d, JC−P = 6.7 Hz), 139.4, 131.4 (d, JC−P = 23.4 Hz),
128.5, 126.6, 113.6 (d, JC−P = 192.7 Hz), 69.4 (d, JC−P = 5.8 Hz), 23.1
(d, JC−P = 4.5 Hz), 23.0 (d, JC−P = 4.5 Hz), 20.4. 31P NMR (CDCl3,
162 MHz): δ 17.7. IR (film): 3469, 2978, 2929, 1614, 1411, 1387,
1242, 1176, 1107, 972, 890, 833. ESI-MS: m/z = 283 [M + H]+. Anal.
Calcd for C15H23O3P: C, 63.82; H, 8.21. Found: C, 64.23; H, 8.47.
Diisopropyl (E)-(3-Methylstyryl)phosphonate (3c, New Com-
= 2.6, 4.1 Hz, 1H), 6.29−6.22 (t, J = 17.4 Hz, 1H),4.78−4.72 (m, 2H),
1.39−1.34 (dd, J = 6.2, 16.1 Hz, 12H). 13C{1H} NMR (125 MHz,
CDCl3): δ 162.1 (d, JC−F = 253.8 Hz), 140.8 (d, JC−P = 8.1 Hz), 134.4
(d, JC−F = 10.3 Hz), 128.8 (d, JC−F = 20.7 Hz), 127.7 (d, JC−F = 9.0
Hz), 118.0 (d, JC−P = 192.4 Hz), 116.4 (d, JC−F = 24.5 Hz), 113.7 (d,
JC−F = 21.5 Hz), 69.8 (d, JC−P = 5.7 Hz), 23.1 (d, JC−P = 3.8 Hz), 23.0
(d, JC−P = 4.9 Hz). 31P NMR (CDCl3, 203 MHz): δ 15.7. IR (film):
3461, 2978, 2938, 1736, 1614, 1601, 1491, 1385, 1242, 1103, 984, 886.
ESI-MS: m/z = 322 [M + H]+. Anal. Calcd for C14H19ClFO3P: C,
52.43; H, 5.97. Found: C, 52.64; H, 6.19.
Diisopropyl (E)-(4-Methoxystyryl)phosphonate (3i, CAS 168025-
52-3). Colorless oil; 125 mg, 84% yield. 1H NMR (400 MHz, CDCl3):
δ 7.48−7.38 (m, 3H), 6.91−6.89 (m, 2H), 6.14−6.06 (t, J = 17.4 Hz,
1H), 4.74−4.66 (m, 2H), 3.83 (s, 3H), 1.37−1.36 (d, J = 6.2 Hz, 6H),
1.32−1.31 (d, J = 6.2 Hz, 6H). 13C{1H} NMR (100 MHz, CDCl3): δ
160.2, 146.4 (d, JC−P = 6.6 Hz), 128.2, 126.9 (d, JC−P = 23.6 Hz),
113.2, 111.8 (d, JC−P = 193.8 Hz), 69.3 (d, JC−P = 5.8 Hz), 23.1 (d,
JC−P = 3.7 Hz), 23.0 (d, JC−P = 3.7 Hz). 31P NMR (CDCl3, 162 MHz):
δ 18.1. ESI-MS: m/z = 321 [M + Na]+. Anal. Calcd for C15H23O4P: C,
60.39; H, 7.77. Found: C, 60.08; H, 7.67.
1
pound). Light yellow oil; 115 mg, 82% yield. H NMR (400 MHz,
CDCl3): δ 7.50−7.40 (dd, J = 22.4, 17.5 Hz, 1H), 7.30−7.24 (m, 3H),
7.19−7.17 (m, 1H), 6.29−6.21 (t, J = 17.5 Hz, 1H), 4.73−4.67 (m,
2H), 1.37−1.36 (d, J = 6.2 Hz, 6H), 1.33−1.31 (d, J = 6.2 Hz, 6H).
13C{1H} NMR (100 MHz, CDCl3): δ 146.9 (d, JC−P = 7.0 Hz), 134.1
(d, JC−P = 23.0 Hz), 129.8, 127.7, 127.2, 123.9, 114.5 (d, JC−P = 192.0
Hz), 69.4 (d, JC−P = 5.2 Hz), 23.1 (d, JC−P =, 4.3 Hz), 23.0 (d, JC−P
=
4.3 Hz), 20.3. 31P NMR (CDCl3, 162 MHz): δ 17.3. IR (film): 3445,
2976, 2929, 1617, 1381, 1371, 1258, 1102, 982, 888. ESI-MS: m/z =
283 [M + H]+. Anal. Calcd for C15H23O3P: C, 63.82; H, 8.21; Found:
C, 63.65; H, 8.39.
Diisopropyl (E)-(4-(Trifluoromethyl)styryl)phosphonate (3j, CAS
1
1262966-58-4). Light yellow oil; 136 mg, 81% yield. H NMR (400
Diisopropyl (E)-(2-Methylstyryl)phosphonate (3d, New Com-
1
MHz, CDCl3): δ 7.66−7.59 (m, 4H), 7.55−7.45 (dd, J = 22.2, 17.4
Hz, 1H), 6.42−6.34 (m, 1H), 4.78−4.70 (m, 2H), 1.39−1.38 (d, J =
6.2 Hz, 6H), 1.34−1.33 (d, J = 6.2 Hz, 6H). 13C{1H} NMR (100
MHz, CDCl3): δ 144.7 (d, JC−P = 6.9 Hz), 137.4 (d, JC−P = 23.5 Hz),
130.6 (q, JC−F = 33.0 Hz), 126.8, 124.8 (q, JC−F = 3.7 Hz), 122.8 (q,
JC−F = 272.6 Hz), 118.0 (d, JC−P = 191.4 Hz), 79.8 (d, JC−P = 5.9 Hz),
23.1 (d, JC−P = 4.4 Hz), 23.0 (d, JC−P = 4.4 Hz). 31P NMR (CDCl3,
162 MHz): δ 17.1. ESI-MS: m/z = 337 [M + H]+. Anal. Calcd for
C15H20F3O3P: C, 53.57; H, 5.99. Found: C, 53.36; H, 6.18.
pound). Light yellow oil; 120 mg, 85% yield. H NMR (400 MHz,
CDCl3): δ 7.79−7.69 (dd, J = 22.8, 17.4 Hz, 1H), 7.52−7.50 (m, 1H),
7.28−7.18 (m, 3H), 6.24−6.15 (dd, J = 18.3, 17.4 Hz, 1H), 4.78−4.67
(m, 2H), 2.43 (s, 3H), 1.38−1.37 (d, J = 6.2 Hz, 6H), 1.34−1.33 (d, J
= 6.2 Hz, 6H). 13C{1H} NMR (100 MHz, CDCl3): δ 145.3 (d, JC−P
=
7.3 Hz), 137.1, 134.2 (d, JC−P = 22.8 Hz), 130.7, 129.7, 126.3, 126.0,
117.2 (d, JC−P = 190.9 Hz), 70.4 (d, JC−P = 5.9 Hz), 24.1 (d, J = 3.9
Hz), 24.0 (d, JC−P = 3.9 Hz), 19.7. 31P NMR (CDCl3, 162 MHz): δ
17.1. IR (film): 3420, 2975, 2932, 1610, 1461, 1381, 1371, 1243, 1105,
1007, 982, 891, 837. ESI-MS: m/z = 283 [M + H]+. Anal. Calcd for
C15H23O3P: C, 63.82; H, 8.21. Found: C, 63.51; H, 8.50.
Diisopropyl (E)-(4-(Trifluoromethoxy)styryl)phosphonate (3k,
1
New Compound). Light yellow oil; 146 mg, 83% yield. H NMR
(500 MHz, CDCl3): δ 7.54−7.52 (m, 2H), 7.50−7.42 (dd, J = 17.5,
22.4 Hz, 1H), 7.23−7.22 (m, 2H), 6.29−6.22 (dd, J = 16.8, 17.3 Hz,
1H), 4.76−4.69 (m, 2H), 1.38−1.37 (d, J = 6.2 Hz, 6H), 1.33−1.32
(d, J = 6.2 Hz, 6H). 13C{1H} NMR (125 MHz, CDCl3): δ 149.3 (q
apparent br s), 144.9 (d, JC−P = 6.7 Hz), 132.7 (d, JC−P = 23.7 Hz),
128.1, 120.1, 119.4 (q, JC−F = 257.9 Hz), 116.0 (d, JC−P = 192.1 Hz),
69.7 (d, JC−P = 5.8 Hz), 23.1 (d, JC−P = 4.4 Hz), 23.0 (d, JC−P = 4.4
Hz). 31P NMR (CDCl3, 203 MHz): δ 16.4. IR (film): 3444, 2979,
2929, 2620, 1766, 1708, 1614, 1465, 1385, 1247, 1207, 1287, 1247,
1098, 1058, 981, 888. ESI-MS: m/z = 375 [M + Na]+. Anal. Calcd for
C15H20F3O4P: C, 51.14; H, 5.72; Found: C, 50.93; H, 5.42.
Diisopropyl (E)-(1-Phenylprop-1-en-2-yl)phosphonate (3e, New
Compound). Yellow oil; 70 mg, 50% yield. 1H NMR (400 MHz,
CDCl3): δ 7.51−7.44 (m, 1H), 7.39−7.38 (m, 4H), 7.34−7.29 (m,
2H), 4.76−4.65 (m, 2H), 2.08−2.04 (dd, J = 15.1, 1.6 Hz, 3H), 1.38−
1.37 (d, J = 6.2 Hz, 6H), 1.32−1.31 (d, J = 6.2 Hz, 6H). 13C{1H}
NMR (100 MHz, CDCl3): δ 140.9 (d, JC−P = 11.7 Hz), 134.9 (d, JC−P
= 24.2 Hz), 128.4, 127.3 127.2, 126.4 (d, JC−P = 179.3 Hz), 69.3 (d,
JC−P = 5.9 Hz), 23.1 (d, JC−P = 3.7 Hz), 22.9 (d, JC−P = 3.7 Hz), 13.5
(d, JC−P = 8.7 Hz). 31P NMR (CDCl3, 162 MHz): δ 19.8. IR (film):
3465, 2978, 2933, 1622, 1450, 1381, 1242, 1107, 1005, 972, 886. ESI-
MS: m/z = 283 [M + H]+. Anal. Calcd for C15H23O3P: C, 63.82; H,
8.21. Found: C, 63.59; H, 8.18.
Diisopropyl (E)-(4-Fluorostyryl)phosphonate (3f, CAS 1262966-
52-8). Yellow oil; 119 mg, 83% yield. 1H NMR (400 MHz, CDCl3): δ
7.50−7.40 (m, 3H), 7.09−7.05 (m, 2H), 6.23−6.14 (t, J = 17.3 Hz,
1H), 4.76−4.68 (m, 2H), 1.38−1.36 (d, J = 6.3 Hz, 6H), 1.33−1.32
(d, J = 6.3 Hz, 6H). 13C{1H} NMR (100 MHz, CDCl3): δ 162.8 (d,
JC−F = 250.6 Hz), 145.4 (d, JC−P = 7.0 Hz), 134.4 (dd, JC−P = 23.7, JC−F
= 3.6 Hz), 128.5 (d, JC−F = 8.3 Hz), 114.9 (d, JC−F = 22.0 Hz), 114.5
(d, JC−P = 193.1 Hz), 69.6 (d, JC−P = 5.4 Hz), 23.2 (d, JC−P = 4.4 Hz),
23.1 (d, JC−P = 4.4 Hz). 31P NMR (CDCl3, 162 MHz): δ 17.0. ESI-
MS: m/z = 287 [M + H]+. Anal. Calcd for C14H20FO3P: C, 58.74; H,
7.04. Found: C, 58.56; H, 7.25
Methyl (E)-4-(2-(Dipropoxyphosphoryl)vinyl)benzoate (3l, New
1
Compound). Colorless oil; 130 mg, 80% yield. H NMR (500 MHz,
CDCl3): δ 8.01−7.99 (m, 2H), 7.52−7.41 (m, 3H), 6.38−6.31 (dd, J =
16.9, 17.3 Hz, 1H), 4.72−4.66 (m, 2H), 3.88 (s, 3H), 1.34−1.33 (d, J
= 6.2 Hz, 6H), 1.29−1.28 (d, J = 6.2 Hz, 6H). 13C{1H} NMR (125
MHz, CDCl3): δ 165.4, 145.2 (d, JC−P = 6.7 Hz), 138.3 (d, JC−P = 23.5
Hz), 130.2, 129.1, 126.5, 117.8 (d, JC−P = 191.4 Hz), 69.7 (d, JC−P
=
5.6 Hz), 51.2, 23.1 (d, JC−P = 4.5, Hz), 23.0 (d, JC−P = 4.5, Hz). 31P
NMR (CDCl3, 203 MHz): δ 16.0. IR (film): 3415, 3009, 2976, 2925,
1719, 1617, 1519, 1432, 1381, 1276, 1236, 1105, 1000, 887. ESI-MS:
m/z = 349 [M + Na]+. Anal. Calcd for C16H23O5P: C, 58.89; H, 7.10.
Found: C, 58.66; H, 7.15.
Diisopropyl (E)-(4-Nitrostyryl)phosphonate (3m, New Com-
Diisopropyl (E)-(4-Chlorostyryl)phosphonate (3g, CAS 202747-
1
1
pound). White solid; 89 mg, 57% yield. Mp: 87−88 °C. H NMR
25-9). Light orange oil; 131 mg, 87% yield. H NMR (400 MHz,
(500 MHz, CDCl3): δ 8.25−8.24 (m, 2H), 7.66−7.64 (m, 2H), 7.55−
7.47 (dd, J = 22.2, 17.4 Hz, 1H), 6.48−6.42 (dd, J = 17.4, 16.0 Hz
1H), 4.80−4.71 (m, 2H), 1.39−1.38 (d, J = 6.2 Hz, 6H), 1.35−1.34
(d, J = 6.2 Hz, 6H). 13C{1H} NMR (125 MHz, CDCl3): δ 147.4, 143.5
(d, JC−P = 6.4 Hz), 140.0 (d, JC−P = 22.8 Hz), 127.3, 123.1, 120.2, (d,
CDCl3): δ 7.48−7.41 (m, 3H), 7.38−7.34 (m, 2H), 6.29−6.20 (t, J =
16.9 Hz, 1H), 4.74−4.68 (m, 2H), 1.38−1.36 (d, J = 6.1 Hz, 6H),
1.33−1.31 (d, J = 6.1 Hz, 6H). 13C{1H} NMR (100 MHz, CDCl3): δ
145.2 (d, JC−P = 6.6 Hz), 134.9, 132.6 (d, JC−P = 23.9 Hz), 127.9 (d,
JC−P = 25.4 Hz), 115.5 (d, JC−P = 192.2 Hz), 69.6 (d, JC−P = 5.9 Hz),
23.0 (d, JC−P = 4.2 Hz), 22.9 (d, JC−P = 4.2 Hz). 31P NMR (CDCl3,
162 MHz): δ 16.6. ESI-MS: m/z = 304 [M + H]+. Anal. Calcd for
C14H20ClO3P: C, 55.54; H, 6.66. Found: C, 55.42; H, 6.87.
JC−P = 190.5 Hz), 70.0 (d, JC−P = 6.0 Hz), 23.1 (t, JC−P = 4.6 Hz). 31
P
NMR (CDCl3, 203 MHz): δ 14.9. IR (film): 3191, 2917, 2844, 1740,
1597, 1450, 1373, 1258, 1111, 1005. ESI-MS: m/z = 314 [M + H]+.
Anal. Calcd for C14H20NO5P: C, 53.67; H, 6.43; N, 4.47. Found: C,
53.49; H, 6.50; N, 4.40.
Dipropyl (E)-(2-Chloro-4-fluorostyryl)phosphonate (3h, New
1
Compound). Yellow oil; 128 mg, 80% yield. H NMR (500 MHz,
CDCl3): δ 7.80−7.72 (dd, J = 17.5, 22.6 Hz, 1H), 7.60−7.57 (dd, J =
6.0, 8.8 Hz, 1H), 7.16−7.14 (dd, J = 2.6, 8.4 Hz, 1H), 7.03−6.99 (dt, J
Diisopropyl (E)-(4-(Dimethylamino)styryl)phosphonate (3n, CAS
625412-80-8). Red oil; 118 mg, 76% yield. 1H NMR (400 MHz,
G
dx.doi.org/10.1021/jo501321m | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
CDCl3): δ 7.44−7.34 (m, 3H), 6.68−6.64 (m, 2H), 6.01−5.93 (t, J =
17.6 Hz, 1H), 4.72−4.64 (m, 2H), 3.00 (s, 6H), 1.36−1.35 (d, J = 6.2
Hz, 6H), 1.31−1.30 (d, J = 6.2 Hz, 6H). 13C{1H} NMR (100 MHz,
CDCl3): δ 150.6, 147.3, 128.2, 122.1 (d, JC−P = 23.8 Hz), 110.8, 108.1
(d, JC−P = 195.9 Hz), 69.0 (d, JC−P = 5.4 Hz), 23.0 (d, JC−P = 4.2 Hz),
22.9 (d, JC−P = 4.2 Hz). 31P NMR (CDCl3, 162 MHz): δ 19.6. ESI-
MS: m/z = 312 [M + H]+. Anal. Calcd for C16H26NO3P: C, 61.72; H,
8.42; N, 4.50. Found: C, 61.50; H, 8.58; N, 4.67.
= 6.4 Hz), 18.7, 13.6. 31P NMR (CDCl3, 203 MHz): δ 19.5. ESI-MS:
m/z = 297 [M + H]+. Anal. Calcd for C16H25O3P: C, 64.85; H, 8.50.
Found: C, 64.53; H, 8.37.
(E)-5,5-Dimethyl-2-styryl-1,3,2-dioxaphosphinane 2-Oxide (3u,
1
CAS 1190078-62-6). Colorless crystal; 87 mg, 69% yield. H NMR
(400 MHz, CDCl3): δ 7.62−7.50 (m, 3H), 7.40−7.38 (m, 3H), 6.35−
6.26 (dd, J = 18.8, 17.5 Hz, 1H), 4.26−4.21 (m, 2H), 3.93−3.87 (m,
2H), 1.13 (s, 3H), 1.08 (s, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ
150.1 (d, JC−P = 6.6 Hz), 134.5 (d, JC−P = 23.6 Hz), 130.5, 128.8,
127.7, 111.8 (d, JC−P = 193.2 Hz), 75.4 (d, JC−P = 5.9 Hz), 32.4 (d,
JC−P = 5.9 Hz), 21.4 (d, JC−P = 16.9 Hz). 31P NMR (CDCl3, 162
MHz): δ 14.9. ESI-MS: m/z = 253 [M + H]+. Anal. Calcd for
C13H17O3P: C, 61.90; H, 6.79; Found: C, 61.68; H, 6.87.
Ethyl (E)-Phenyl(styryl)phosphinate (3v, CAS 82943-05-3). Light
yellow oil; 125 mg, 92% yield. 1H NMR (400 MHz, CDCl3): δ 7.88−
7.83 (m, 2H), 7.56−7.46 (m, 6H), 7.37−7.34 (m, 3H), 6.54−6.45 (dd,
J = 20.4, 17.5 Hz, 1H), 4.18−4.02 (m, 2H), 1.38−1.35 (t, J = 7.0 Hz,
3H). 13C{1H} NMR (100 MHz, CDCl3): δ 146.8 (d, JC−P = 5.5 Hz),
Diisopropyl (E)-(2-([1,1′-Biphenyl]-4-yl)vinyl)phosphonate (3o,
1
New Compound). Colorless oil; 114 mg, 66% yield. H NMR (500
MHz, CDCl3): δ 7.61−7.57 (m, 6H), 7.55−7.49 (m, 1H), 7.45−7.42
(m, 2H), 7.45−7.42 (m, 2H), 7.37−7.34 (m, 2H), 6.34−6.27 (t, J =
17.4 Hz, 1H), 4.77−4.70 (m, 2H), 1.39−1.37 (d, J = 6.2 Hz, 6H),
1.34−1.33 (d, J = 6.2 Hz, 6H). 13C{1H} NMR (125 MHz, CDCl3): δ
146.2 (d, JC−P = 6.7 Hz), 141.8, 139.2, 133.0 (d, JC−P = 23.6 Hz),
127.9, 127.1, 126.8, 126.5, 126.0, 114.6 (d, JC−P = 192.4 Hz), 69.5 (d,
JC−P = 5.6 Hz), 23.1 (d, JC−P = 3.9 Hz), 23.0 (d, JC−P = 4.8 Hz). 31P
NMR (CDCl3, 203 MHz): δ 17.3. IR (film): 3465, 3027, 2978, 2933,
1704, 1614, 1487, 1385, 1246, 1107, 988, 886, 825. ESI-MS: m/z =
345 [M + H]+. Anal. Calcd for C20H25O3P: C, 69.75; H, 7.32. Found:
C, 69.84; H, 7.63.
134.0 (d, JC−P = 20.1 Hz), 131.1 (d, JC−P = 2.9 Hz), 130.6 (d, JC−P
138.1 Hz), 130.4 (d, JC−P = 10.0 Hz), 129.1, 127.8, 127.6 (d, JC−P
=
=
13.2 Hz), 126.7, 117.1 (d, JC−P = 139.7 Hz), 69.8 (d, JC−P = 5.9 Hz),
15.5 (d, JC−P = 6.6 Hz). 31P NMR (CDCl3, 162 MHz): δ 31.1. ESI-
MS: m/z = 273 [M + H]+. Anal. Calcd for C16H17O2P: C, 70.58; H,
6.29. Found: C, 70.34; H, 6.55.
Diisopropyl (E)-(2-(Naphthalen-2-yl)vinyl)phosphonate (3p, CAS
1
1262966-60-8). Yellow oil; 91 mg, 57% yield. H NMR (500 MHz,
CDCl3): δ 7.89−7.51 (m, 4H), 7.68−7.60 (m, 2H), 7.51−7.49 (m,
2H), 6.42−6.35 (t, J = 17.4, 1H), 4.80−4.72 (m, 2H), 1.40−1.38 (d, J
= 6.2 Hz, 6H), 1.35−1.34 (d, J = 6.2 Hz, 6H). 13C{1H} NMR (125
MHz, CDCl3): δ 146.7 (d, JC−P = 6.4 Hz), 133.1, 132.3, 131.6 (d, JC−P
= 23.6 Hz), 128.2, 127.6, 127.5, 126.7, 126.1, 125.7, 122.3, 114.9 (d,
JC−P = 192.3 Hz), 69.5 (d, JC−P = 5.5 Hz), 23.1 (d, JC−P = 3.6 Hz), 23.0
(d, JC−P = 3.6 Hz). 31P NMR (CDCl3, 203 MHz): δ 17.3. ESI-MS: m/
z = 319 [M + H]+. Anal. Calcd for C18H23O3P: C, 67.91; H, 7.28.
Found: C, 67.70; H, 7.61.
Diisopropyl (E)-(2-(Perfluorophenyl)vinyl)phosphonate (3q, New
Compound). Light brown oil; 95 mg, 53% yield. 1H NMR (400 MHz,
CDCl3): δ 7.44−7.34 (dd, J = 17.9, 24.0 Hz, 1H), 6.68−6.59 (t, J =
17.4 Hz, 1H), 4.77−4.69 (m, 2H), 1.38−1.32 (dd, J = 6.2, 16.8 Hz,
12H). 13C{1H} NMR (100 MHz, CDCl3): δ 166.7, 145.8−143.3 (m),
138.0−135.6 (m), 129.9−129.8 (m), 126.2−124.2 (m), 109.8−109.3
Ethyl (E)-(4-Methoxystyryl)(phenyl)phosphinate (3w, New Com-
1
pound). Light yellow oil; 110 mg, 73% yield. H NMR (400 MHz,
CDCl3): δ 7.85−7.80 (m, 2H), 7.50−7.40 (m, 6H), 6.86−6.84(m,
2H), 6.35−6.26 (dd, J = 20.5, 17.4 Hz, 1H), 4.14−3.98 (m, 2H), 3.77
(s, 3H), 1.35−1.31 (t, J = 7.1 Hz, 3H). 13C{1H} NMR (100 MHz,
CDCl3): δ 161.1, 147.3 (d, JC−P = 5.8 Hz), 131.9 (d, JC−P = 2.2 Hz),
131.6 (d, JC−P = 137.9 Hz), 131.2 (d, JC−P = 10.2 Hz), 129.2, 128.4 (d,
JC−P = 12.9 Hz), 127.6 (d, JC−P = 20.5 Hz), 115.4, 114.0, 60.6 (d, JC−P
= 5.8 Hz), 55.2, 16.4 (d, JC−P = 6.6 Hz). 31P NMR (CDCl3, 162
MHz): δ 31.7. IR (film): 3421, 2510, 1534, 1448, 1110, 971, 842. ESI-
MS: m/z = 325 [M + Na]+. Anal. Calcd for C17H19O3P: C, 67.54; H,
6.34. Found: C, 67.46; H, 6.51.
Ethyl (E)-Phenyl(4-(trifluoromethyl)styryl)phosphinate (3x, New
1
Compound). Light brown oil; 138 mg, 81% yield. H NMR (400
(m), 70.1 (d, JC−P = 5.8 Hz), 23.1 (d, JC−P = 4.4 Hz), 23.0 (d, JC−P
=
MHz, CDCl3): δ 7.87−7.82 (m, 2H), 7.61−7.46 (m, 8H), 6.64−6.55
(dd, J = 19.6, 17.5 Hz, 1H), 4.18−4.01 (m, 2H), 1.37−1.34 (t, J = 7.1
Hz, 3H). 13C{1H} NMR (100 MHz, CDCl3): δ 145.7 (d, JC−P = 5.7
4.4 Hz). 31P NMR (CDCl3, 203 MHz): δ 14.0. IR (film): 2962, 1728,
1650, 1601, 1524, 1495, 1254, 1103, 1009, 849. ESI-MS: m/z = 359
[M + H]+. Anal. Calcd for C14H16F5O3P: C, 46.94; H, 4.50. Found: C,
47.32; H, 4.85.
Hz), 138.2 (d, JC−P = 19.9 Hz), 132.3 (d, J = 2.7 Hz), 131.6 (q, JC−F
=
12.6 Hz), 131.4 (d, J = 10.2 Hz), 130.2, 128.6 (d, J = 13.1 Hz), 127.8,
Diisopropyl (E)-(2-(Thiophene-2-yl)vinyl)phosphonate (3r, New
Compound). Yellow oil; 79 mg, 58% yield. 1H NMR (500 MHz,
CDCl3): δ 7.59−7.52 (dd, J = 17.2, 21.8 Hz, 1H), 7.34−7.44 (m, 1H),
7.19−7.18 (m, 1H), 7.04−7.02 (dd, J = 3.6, 4.8 Hz, 1H), 6.05−5.98 (t,
J = 16.8 Hz, 1H), 4.73−4.66 (m, 2H), 1.37−1.35 (d, J = 6.2 Hz, 6H),
1.33−1.31 (d, J = 6.2 Hz, 6H). 13C{1H} NMR (125 MHz, CDCl3): δ
139.7 (d, JC−P = 26.5 Hz), 139.1 (d, JC−P = 7.5 Hz), 128.8, 126.9,
126.8, 113.5 (d, JC−P = 194.3 Hz), 69.5 (d, JC−P = 5.5 Hz), 23.1 (d,
JC−P = 4.5 Hz), 23.0 (d, JC−P = 4.5 Hz). 31P NMR (CDCl3, 203 MHz):
δ 16.7. IR (film): 2954, 2921, 2852, 1454, 1376, 1254, 1005, 976. ESI-
MS: m/z = 275 [M + H]+. Anal. Calcd for C12H19O3PS: C, 52.54; H,
6.98. Found: C, 52.67; H, 6.81.
Diethyl (E)-Styrylphosphonate (3s, CAS 20408-33-7). Colorless
oil; 109 mg, 91% yield. 1H NMR (400 MHz, CDCl3): δ 7.56−7.46 (m,
3H), 7.40−7.36 (m, 3H), 6.30−6.22 (t, J = 17.6 Hz, 1H), 4.18−4.10
(m, 4H), 1.37−1.34 (t, J = 7.1 Hz, 6H). 13C{1H} NMR (100 MHz,
CDCl3): δ 147.7 (d, JC−P = 6.2 Hz), 133.9 (d, JC−P = 22.9 Hz), 129.2,
127.8, 126.7, 113.0 (d, JC−P = 191.0 Hz), 60.9 (d, JC−P = 5.2 Hz), 15.4
(d, JC−P = 6.4 Hz). 31P NMR (CDCl3, 162 MHz): δ 19.5. ESI-MS: m/
z = 241 [M + H]+. Anal. Calcd for C12H17O3P: C, 60.00; H, 7.13.
Found: C, 59.71; H, 7.32.
125.6 (q, JC−F = 3.7 Hz), 123.7 (q, JC−F = 272.2 Hz), 121.2 (d, JC−P
=
137.6 Hz), 60.9 (d, JC−P = 5.8 Hz), 16.4 (d, JC−P = 6.6 Hz). 31P NMR
(CDCl3, 162 MHz): δ 30.1. IR (film): 3465, 2980, 1760, 1553, 1256,
1185, 1117, 983. ESI-MS: m/z = 341 [M + H]+. Anal. Calcd for
C17H16F3O2P: C, 60.01; H, 4.74. Found: C, 59.88; H, 4.93.
(E)-Diphenyl(styryl)phosphine Oxide (3y, CAS 3582-82-9). White
1
solid; 122 mg, 80% yield. H NMR (400 MHz, CDCl3): δ 7.79−7.73
(m, 3H), 7.56−7.45 (m, 9H), 7.37−7.35 (m, 3H), 6.90−6.80 (dd, J =
22.3, 17.4 Hz, 1H). 13C{1H} NMR (100 MHz, CDCl3): δ 146.5 (d,
JC−P = 3.6 Hz), 134.2 (d, JC−P = 17.7 Hz), 132.0 (d, JC−P = 105.8 Hz),
130.8 (d, JC−P = 2.0 Hz), 130.4 (d, JC−P = 10.2 Hz), 129.1, 127.8, 127.6
(d, JC−P = 12.2 Hz), 126.7, 118.8 (d, JC−P = 103.7 Hz). 31P NMR
(CDCl3, 162 MHz): δ 24.4. ESI-MS: m/z = 305 [M + H]+. Anal.
Calcd for C20H17OP: C, 78.93; H, 5.63. Found: C, 78.71; H, 5.90.
(E)-(4-Methoxystyryl)diphenylphosphine Oxide (3z, CAS 59675-
60-4). White solid; 130 mg, 78% yield. 1H NMR (400 MHz, CDCl3):
δ 7.78−7.74 (m, 4H), 7.54−7.40 (m, 9H), 6.90−6.88 (m, 2H), 6.72−
6.64 (dd, J = 22.2, 17.4 Hz, 1H), 3.81 (s, 3H), 13C{1H} NMR (100
MHz, CDCl3): δ 161.1, 147.0 (d, JC−P = 3.9 Hz), 133.3 (d, JC−P
=
105.7 Hz), 131.6, 131.3 (d, JC−P = 9.9 Hz), 129.3, 128.5 (d, JC−P = 11.9
Hz), 128.0 (d, JC−P = 18.2 Hz), 116.3 (d, JC−P = 106.1 Hz), 114.2,
55.3. 31P NMR (CDCl3, 162 MHz): δ 24.7. ESI-MS: m/z = 357 [M +
Na]+. Anal. Calcd for C21H19O2P: C, 75.44; H, 5.73. Found: C, 75.63;
H, 5.99.
(E)-Diphenyl(4-(trifluoromethyl)styryl)phosphine Oxide (3jf, CAS
1429762-73-1). Light yellow solid; 156 mg, 84% yield. 1H NMR (500
MHz, CDCl3): δ 7.78−7.74 (m, 4H), 7.61−7.45 (m, 11H), 7.02−6.94
Dibutyl (E)-Styrylphosphonate (3t, CAS 146896-99-3). Light
yellow oil; 99 mg, 67% yield. 1H NMR (500 MHz, CDCl3): δ
7.56−7.45 (m, 3H), 7.40−7.39 (m, 3H), 6.31−6.21 (m, 1H), 7.08−
7.05 (m, 4H), 1.69−1.68 (m, 4H), 1.44−1.41 (m, 4H), 0.96−0.92 (m,
6H). 13C{1H} NMR (125 MHz, CDCl3): δ 148.6 (d, JC−P = 6.8 Hz),
130.2, 128.8, 127.7, 114.9, 113.0, 65.5 (d, JC−P = 6.7 Hz), 32.5 (d, JC−P
H
dx.doi.org/10.1021/jo501321m | J. Org. Chem. XXXX, XXX, XXX−XXX

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Article
(dd, J = 21.9, 17.4 Hz, 1H). 13C{1H} NMR (125 MHz, CDCl3): δ
Lim, K. G.; Loveridge, C.; Long, J.; Pitson, S. M.; Tigyi, G.; Bittman,
R.; Pyne, S.; Pyne, N. J. Cell. Signalling 2010, 22, 1536.
145.5 (d, JC−P = 3.3 Hz), 138.4 (d, JC−P = 17.5 Hz), 132.5 (d, JC−P
=
106.4 Hz), 131.9, 131.5 (q, JC−F = 33.5 Hz), 131.2 (d, JC−P = 10.0 Hz),
128.6 (d, JC−P = 12.4 Hz), 127.8, 125.7 (q, JC−F = 3.6 Hz), 123.7 (q,
JC−F = 273.6 Hz), 122.6 (d, JC−P = 102.2 Hz). 31P NMR (CDCl3, 203
MHz): δ 22.9. ESI-MS: m/z = 373 [M + H]+. Anal. Calcd for
C21H16F3OP: C, 67.74; H, 4.33. Found: C, 68.07; H, 4.45.
(3) (a) Price, D.; Pyrah, K.; Hull, T. R.; Milnes, G. J.; Ebdon, J. R.;
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M.; Honma, I. Polymer 2005, 46, 2986. (c) Ajellal, N.; Thomas, C. M.;
Carpentier, J.-F. Polymer 2008, 49, 4344. (d) Macarie, L.; Ilia, G. Prog.
Polym. Sci. 2010, 35, 1078 and references cited therein.
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Diisopropyl (Phenylethynyl)phosphonate (5a, CAS 204009-80-3).
1
Colorless oil; 30 mg, 45% yield. H NMR (500 MHz, CDCl3): δ
7.57−7.55 (m, 2H), 7.47−7.44 (m, 1H), 7.40−7.37 (m, 2H), 4.85−
4.80 (m, 2H), 1.43 (d, J = 3.0 Hz, 6H), 1.42 (d, J = 3.0 Hz, 6H).
13C{1H} NMR (125 MHz, CDCl3): δ 132.5 (d, JC−P = 2.4 Hz), 130.5,
128.5, 119.8 (d, JC−P = 5.5 Hz), 98.1 (d, JC−P = 52.8 Hz), 72.3 (d, JC−P
= 5.5 Hz), 23.9 (d, JC−P = 4.5 Hz), 23.6 (d, JC−P = 4.9 Hz). 31P NMR
(CDCl3, 203 MHz): δ −8.5. ESI-MS: m/z = 267 [M + H]+.
Diisopropyl ((4-Methoxyphenyl)ethynyl)phosphonate (5b, CAS
1
1310329-76-0). Colorless oil; 27 mg, 36% yield. H NMR (CDCl3,
400 MHz): δ 7.51−7.50 (m, 2H), 6.90−6.88 (m, 2H), 4.86−4.78 (m,
2H), 3.85 (s, 3H), 1.43−1.42 (d, J = 1.8 Hz, 6H), 1.41−1.40 (d, J = 1.8
Hz, 6H); 13C NMR (CDCl3, 100 MHz): δ 161.3, 134.3 (d, JC−P = 2.4
Hz), 114.2, 111.7 (d, JC−P = 5.6 Hz), 98.8 (d, JC−P = 53.0 Hz), 78.5 (d,
JC−P = 298.6 Hz), 72.2 (d, JC−P = 5.4 Hz), 55.4, 23.9 (d, JC−P = 4.7
Hz), 23.6 (d, JC−P = 4.7 Hz); 31P NMR (CDCl3, 163 MHz): δ −8.0;
ESI-MS: m/z = 297 [M + H]+.
Woj
́
ciuk, G.; Demchuk, O. M.; Grela, K.; Pietrusiewicz, K. M.;
Butenschon, H. Adv. Synth. Catal. 2006, 348, 931.
̈
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Diisopropyl ((4-(Trifluoromethyl)phenyl)ethynyl)phosphonate
1
(5c, CAS 1549706-37-7). Colorless oil; 33 mg, 40% yield. H NMR
(500 MHz, CDCl3): δ 7.69−7.64 (m, 2H), 7.47−7.44 (m, 4H), 4.88−
4.81 (m, 2H), 1.44−1.43 (d, J = 3.0 Hz, 6H), 1.43−1.42 (d, J = 2.9 Hz,
6H). 13C{1H} NMR (125 MHz, CDCl3): δ 132.8 (d, JC−P = 2.1 Hz),
132.0 (q, JC−P = 33.1 Hz), 125.5 (q, JC−P = 4.7 Hz), 123.5 (d, JC−P
=
(8) Selected publications: (a) Han, L.-B.; Zhao, C.-Q.; Onozawa, S.;
Goto, M.; Tanaka, M. J. Am. Chem. Soc. 2002, 124, 3842. (b) Han, L.-
B.; Zhang, C.; Yazawa, H.; Shimada, S. J. Am. Chem. Soc. 2004, 126,
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(e) Ananikov, V. P.; Khemchyan, L. L.; Beletskaya, I. P.; Starikova, Z.
A. Adv. Synth. Catal. 2010, 352, 2979. (f) Evano, G.; Gaumont, A.-C.;
Alayrac, C.; Wrona, I. E.; Giguere, J. R.; Delacroix, O.; Bayle, A.;
Jouvin, K.; Theunissen, C.; Gatignol, J.; Silvanus, A. C. Tetrahedron
2014, 70, 1529.
5.3 Hz), 123.5 (q, JC−P = 269.8 Hz), 95.9 (d, JC−P = 52.0 Hz), 82.1 (d,
JC−P = 292.9 Hz), 72.7 (d, JC−P = 5.5 Hz), 23.9 (d, JC−P = 4.7 Hz), 23.6
(d, JC−P = 5.6 Hz); 31P NMR (CDCl3, 203 MHz): δ −9.4. ESI-MS: m/
z = 355 [M + H]+.
ASSOCIATED CONTENT
■
S
* Supporting Information
Copies of 1H NMR and 13C{1H} NMR spectra. This material is
available free of charge via the Internet at http://pubs.acs.org.
(9) Gooßen, L. J.; Gooßen, K. Top. Organomet. Chem. 2013, 44, 121.
(10) Rokade, B. V.; Prabhu, K. R. Org. Biomol. Chem. 2013, 11, 6713.
(11) Duan, Z.; Ranjit, S.; Zhang, P.; Liu, X. Chem.Eur. J. 2009, 15,
3666.
AUTHOR INFORMATION
Corresponding Author
*E-mail: gaoxingchem@xmu.edu.cn.
Notes
■
(12) Hu, J.; Zhao, N.; Yang, B.; Wang, G.; Guo, L.-N.; Liang, Y.-M.;
Yang, S.-D. Chem.Eur. J. 2011, 17, 5516.
The authors declare no competing financial interest.
(13) Li, X.; Yang, F.; Wu, Y.; Wu, Y. Org. Lett. 2014, 16, 992.
(14) Selected recent references: (a) Shang, R.; Fu, Y.; Li, J.-B.;
Zhang, S.-L.; Guo, Q.-X.; Liu, L. J. Am. Chem. Soc. 2009, 131, 5738.
(b) Bi, H.-P.; Zhao, L.; Liang, Y.-M.; Li, C.-J. Angew. Chem., Int. Ed.
2009, 48, 792. (c) Wang, C.; Rakshit, S.; Glorius, F. J. Am. Chem. Soc.
2010, 132, 14006. (d) Rodríguez, N.; Goossen, L. J. Chem. Soc. Rev.
2011, 40, 5030. (e) Cornella, J.; Larrosa, I. Synthesis 2012, 44, 653.
(f) Miao, J.; Ge, H. Org. Lett. 2013, 15, 2930.
ACKNOWLEDGMENTS
■
This work was supported by the Chinese National Natural
Science Foundation (Nos. 21202135 and 21375113), NFFTBS
(No. J1210014), and the National Basic Research Program of
China (Noes. 2012CB821600 and 2013CB910700).
(15) (a) Yoshino, Y.; Kurahashi, Y.; Matsubara, S. J. Am. Chem. Soc.
2009, 131, 7494. (b) Choe, J.; Yang, J.; Park, K.; Palani, T.; Lee, S.
Tetrahedron Lett. 2012, 53, 6908. (c) Yang, K.; Zhang, C.; Wang, P.;
Zhang, Y.; Ge, H. Chem.Eur. J. 2014, 20, 7241.
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