Lanthanum-Catalyzed Regioselective Anti-Markovnikov Hydrophosphinylation of Styrenes

Article abstract of DOI:10.1021/acs.organomet.9b00549

A useful and convenient method for sp³ C-P(O) bond formation via direct regioselective hydrophosphinylation of simple and readily available alkenes using a lanthanum-based N,N-dimethylbenzylamine complex (La(DMBA)₃) as a precatalyst is demonstrated. The reaction proceeds with perfect atom economy for a wide range of styrenes with secondary phosphine oxides, giving moderate to excellent yields.

Full text of DOI:10.1021/acs.organomet.9b00549

Article
pubs.acs.org/Organometallics
Cite This: Organometallics XXXX, XXX, XXX−XXX
Lanthanum-Catalyzed Regioselective Anti-Markovnikov
Hydrophosphinylation of Styrenes
Yesmin Akter Rina and Joseph A. R. Schmidt*
Department of Chemistry & Biochemistry, School of Green Chemistry and Engineering, College of Natural Sciences and
Mathematics, The University of Toledo, 2801 West Bancroft Street MS 602, Toledo, Ohio 43606-3390, United States
S
* Supporting Information
ABSTRACT: A useful and convenient method for sp3 C−P(O) bond
formation via direct regioselective hydrophosphinylation of simple and
readily available alkenes using a lanthanum-based N,N-dimethylbenzyl-
amine complex (La(DMBA)3) as a precatalyst is demonstrated. The
reaction proceeds with perfect atom economy for a wide range of
styrenes with secondary phosphine oxides, giving moderate to excellent
yields.
and Ni21) hydrophosphinylation of alkynes (Scheme 1). Very
recently, Dong reported Pd-catalyzed hydrophosphinylation of
INTRODUCTION
■
Due to the wide practical applications of organophosphorus
1,3-dienes, affording chiral allylic phosphine oxide com-
compounds1 containing a phosphoryl group (PO; phos-
pounds.22
phonates, phosphinates, and phosphine oxides) in medicinal
chemistry,2 agrochemistry,3 biological chemistry,4 materials
Despite these advancements, the regioselective hydro-
chemistry,5 organic synthesis,6 pharmaceuticals,7 and organo-
metallic catalysis,8 an efficient and atom-economical con-
struction of C−P(O) building blocks has engendered
significant research interest. Moreover, organophosphorus
compounds have also been utilized as chelating agents,9 as
inhibitors, and most commonly as ligands for metal
stabilization in metal-catalyzed reactions.10 Despite these
tremendous applications of organophosphoryl compounds in
both laboratory and industry, general and efficient methods for
their preparation still represent significant challenges.11
Traditionally, the famous Michaelis−Arbuzov reaction has
been used for their preparation, although it requires toxic alkyl
halide precursors and harsh conditions (high temperature
>150 °C) and suffers from low atom efficiency, low functional
group tolerance, and the environmental problems associated
with toxic waste products.12
As a means to address the drawbacks of the traditional
synthetic method and to fulfill modern demands for more
efficient production of phosphoryl compounds, various efforts
have been undertaken.13 Recently, Han demonstrated several
elegant approaches for the preparation of C−P(O) building
blocks, including an alcohol-based Michaelis−Arbuzov reac-
tion,14 the Ni-catalyzed phosphorylation of sp3 C−CN species
with secondary phosphine oxides,15 and the reductive addition
of P(O)H to terminal alkynes.16 An attractive alternative
approach involving hydrophosphinylation17 (addition of the
H−P bond of a secondary phosphine oxide across an
unsaturated C−C bond)18 represents a powerful potential
strategy. In the past two decades, several groups have
demonstrated the transition-metal-catalyzed (Pd,13c,19 Rh,20
phosphinylation of alkenes for the formation of C−P(O)
bonds still represents an area of high significance. In 2009,
Ogawa first reported photoinduced hydrophosphinylation of
aliphatic alkenes with diphenylphosphine oxide.23 Kobayashi
later disclosed a photocatalytic hydrophosphinylation of
unactivated aliphatic alkenes with secondary phosphine
oxides.24 Recently, Liu reported a silver-initiated free-radical
intermolecular hydrophosphinylation of unactivated alkenes in
which styrenes and their derivatives were not compatible.25 To
the best of our knowledge, direct hydrophosphinylation of aryl
alkenes affording the regiospecific anti-Markovnikov addition
product (β-arylphosphine oxide) mediated by the rare-earth
metal lanthanum (La) has not yet been realized.
RESULTS AND DISCUSSION
■
In connection with our ongoing interest in the production of
new C−P and C−P(O) bonds using rare-earth-metal catalysts,
we have recently demonstrated La(III)-catalyzed hydro-
phosphination of heterocumulenes,26 double hydrophosphiny-
lation of nitriles,27 and hydrophosphination and hydro-
phosphinylation of alkynes.28 Inspired by these advancements
and to fill the need for hydrophosphinylation of alkenes,
accessing the C−P(O) linkage, herein we disclose the direct
hydrophosphinylation of styrenes, affording only the anti-
Markovnikov addition product using a La(III) catalyst
(La(DMBA)3) in an efficient, attractive, and atom-economical
Received: August 12, 2019
© XXXX American Chemical Society
A
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Scheme 1. Hydrophosphinylation of Unsaturated C−C
Bonds
Table 1. Optimization of La(DMBA)3-Catalyzed
Hydrophosphinylation of Styrene
a
styrene
(equiv)
HP(O)Ph2
(equiv)
La(DMBA)3
(mol %)
temp
(°C)
yield
(%)
entry
1
2
3
4
5
6
7
8
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.5
1.0
1.0
1.0
1.0
1.0
1.0
1.3
1.0
5
5
5
0
2.5
10
5
25
60
80
80
80
80
80
80
6
60
82
0
63
79
97
86
5
a
Optimized catalysis conditions: alkene 1a (0.5 mmol), diphenyl-
phosphine oxide 2a (0.65 mmol), La(DMBA)3 (5 mol %, 0.025
mmol, 13.55 mg), pyridine (1 mL), 16 h, 80 °C. Yields were
calculated on the basis of the crude NMR spectra using 1,3-
benzodioxole as an internal standard.
With the optimized catalysis conditions in hand, we first
explored the scope of alkene substrates amenable to this
reaction (Table 2). It was found that a wide range of styrenes
were well-suited to the reaction conditions. Electron-deficient
aromatic alkenes bearing cross-coupling-ready functional
groups such as halogens generated the desired products 3g−
k in good to excellent yields. Moreover, styrenes bearing the
electron-withdrawing bromo group at the para, meta, or ortho
position reacted with diphenylphosphine oxide under the
standard reaction conditions to provide the corresponding
products 3i−k in excellent yields, irrespective of the
substitution position. Also, the medicinally relevant highly
fluorinated moiety 2,3,4,5,6-pentafluorostyrene worked well in
the catalysis, providing the desired product 3l in moderate
yield. Additional experiments showed that p-nitrostyrene was
also tolerant to the reaction conditions, resulting in the
formation of the desired product 3f with reasonable yield.
Aromatic alkenes bearing electron-donating substituents such
as Me or t-Bu at the para position afforded the corresponding
products 3b,c in moderate yields, although a slightly higher
catalyst loading (7.5 mol %) was required. 3-Methoxystyrene
underwent hydrophosphinylation, providing an excellent yield
of the desired product 3d under the standard reaction
conditions, whereas the reaction of 4-methoxystyrene
proceeded quite slowly but gave a reasonable yield of 56% of
the corresponding product 3e after several days. Finally, to our
delight, heteroaromatics such as pyridine, benzodioxole, furan,
and thiophene were tolerated, furnishing the desired products
3m−q in moderate to excellent yields. Unfortunately, the
reaction was not without limits and aliphatic alkenes proved to
be unreactive, while α-methylstyrene and β-methylstyrene gave
only negligible yields of the desired products even at high
temperature (110 °C) and elongated reaction times.
manner (Scheme 1). As part of our reaction design, we decided
to use styrenes and secondary phosphine oxides as our
precursors since both are commercially available, are used as
chemical feedstocks, and are easy to synthesize. In addition,
secondary phosphine oxides are air and moisture stable, easy to
handle, and easy to synthesize and are readily reduced to the
corresponding phosphine.29
On the basis of our previous work with La-based catalysts,
we felt that La(DMBA)3 would serve as a good precatalyst for
styrene hydrophosphinylation. To validate this hypothesis, an
initial screening reaction utilized styrene 1a and diphenylphos-
phine oxide 2a as test substrates with La(DMBA)3 (5 mol %)
in pyridine at room temperature. Gratifyingly, the reaction
furnished the desired product 3a, albeit in merely 6% yield
(Table 1, entry 1). Encouraged by the production of 3a, but
disappointed in the overall yield, we increased the temperature
from room temperature to 60 and 80 °C, resulting in
increasing yields of the product from 6% to 60% and 82%,
respectively (Table 1, entries 2 and 3). After that, a careful
screening of different catalyst loadings revealed that 5 mol % of
La(DMBA)3 was optimal for the reaction and confirmed that,
in the absence of precatalyst, no product was observed (Table
1, entries 3−6). Furthermore, an increase in the amount of
HP(O)Ph2 from 1.0 to 1.3 equiv increased the yield of the
desired product to 97% (Table 1, entry 7). Alternatively,
increasing the amount of alkene from 1.0 to 1.5 equiv had a
less dramatic effect (Table 1, entry 8). On the basis of these
optimization studies, we found that a combination of styrene
(0.50 mmol), HP(O)Ph2 (0.65 mmol), and 5 mol % of
La(DMBA)3 in pyridine at 80 °C provided the optimal
conditions for this catalysis.
Next, we turned our attention to investigation of the
functional group tolerance in the secondary phosphine oxide
component of these reactions, as shown in Table 3. We
observed that diaryl phosphine oxides bearing electron-
donating substituents such as −Me, −OMe, and −tBu in the
para position led to the predicted products 3s−u in excellent
yields. Furthermore, a disubstituted diaryl phosphine oxide was
B
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a
Table 2. Hydrophosphinylation of Styrenes
a
Reaction conditions: alkene 1 (0.5 mmol), diphenylphosphine oxide 2a (0.65 mmol), La(DMBA)3 (5 mol %, 0.025 mmol, 13.55 mg), pyridine (1
mL), 16 h, 80 °C unless otherwise specified. Legend for alternative reaction conditions: (*) alkene 1 (0.5 mmol), diphenylphosphine oxide 2a
(0.725 mmol), La(DMBA)3 (7.5 mol %, 0.0375 mmol, 20.32 mg), pyridine (1 mL), 16 h, 80 °C; (**) alkene 1 (0.5 mmol), diphenylphosphine
oxide 2a (0.65 mmol), La(DMBA)3 (5 mol %, 0.025 mmol, 13.55 mg), pyridine (1 mL), 3 days, 80 °C. Isolated yields are reported.
also tolerated by the standard catalytic conditions to give the
desired product 3v in high yield. Additionally, a bulky
naphthyl- substituted secondary phosphine oxide underwent
the transformation, leading to the predicted product 3w in high
yield. In contrast, diaryl phosphine oxides bearing electron-
withdrawing substituents at the para position were not suitable
for this catalysis. For example, bis(4-chlorophenyl)phosphine
oxide gave only trace amounts of desired product and bis(4-
(trifluoromethyl)phenyl)phosphine oxide did not produce any
product. Also, di-tert-butyl phosphine oxide did not undergo
the reaction.
In order to demonstrate the practical applicability of this
catalytic system, we scaled up the reaction (Scheme 2). A
gram-scale reaction of styrene (1.04 g, 10 mmol) with
diphenylphosphine oxide (2.63 g, 13 mmol) using La-
(DMBA)3 (0.271 g, 0.500 mmol) in 10 mL of pyridine at 80
°C provided 1.9 g of the desired product β-arylphosphine
oxide in 62% isolated yield after 16 h.
C
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a
Table 3. Hydrophosphinylation of Styrene with Various Phosphine Oxides
a
Reaction conditions: alkene 1a (0.5 mmol), diarylphosphine oxide 2 (0.65 mmol), La(DMBA)3 (5 mol %, 0.025 mmol, 13.55 mg), pyridine (1
mL), 16 h, 80 °C. Legend for alternative reaction conditions: (#) alkene 1a (0.25 mmol), diarylphosphine oxide 2 (0.4 mmol), La(DMBA)3 (5 mol
%, 0.0125 mmol, 6.775 mg), pyridine (0.75 mL), 16 h, 80 °C. Isolated yields are reported.
Scheme 2. Scale-Up Experiment
Scheme 3. Plausible Catalytic Cycle for
Hydrophosphinylation of Alkenes Using La(DMBA)3
Precatalyst
On the basis of literature precedents and our own
observations,26−28 we hypothesize that this reaction takes
place utilizing the catalytic cycle depicted in Scheme 3. The
precatalyst La(DMBA)3 is first activated by reaction with 3
equiv of HP(O)Ar2, generating the active catalyst La(P(O)-
Ar2)3 (complex (A)) via protonolysis. Complex (A) then
undergoes insertion of the styrene to produce intermediate (B)
via a [3 + 2] transition state similar to that observed with
terminal alkynes.28 Finally, protonolysis of intermediate (B) by
a secondary phosphine oxide furnishes the desired product and
regenerates the active catalyst (A).
CONCLUSIONS
■
In conclusion, we have developed a regiospecific hydro-
phosphinylation of styrenes with secondary phosphine oxides
using the rare-earth-metal catalyst lanthanum tris(N,N-
dimethylbenzylamine) (La(DMBA)3). These results provide
a straightforward and efficient approach to access β-
arylphosphine oxides in an atom-economical manner with
reduced waste and reduced energy consumption. This
transformation exhibits good functional group tolerance and
broad substrate scope for many combinations of styrenes and
secondary phosphine oxides under mild conditions.
EXPERIMENTAL SECTION
■
General Information. Lanthanum tris(N,N-dimethylbenzyl-
amine) (La(DMBA)3) was synthesized according to the procedure
previously published by our laboratory.30 Diphenylphosphine oxide
was purchased from AK Scientific, dried under vacuum, transferred
into the glovebox, and used without further purification. Secondary
phosphine oxide substrates for products 3s−w were prepared
according to reported methods.31 Styrene substrates were purchased
from Oakwood, Alfa, Aldrich, Acros, or AK Scientific. Styrene
substrates for products 3d,e,j,o−q were synthesized according to
D
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literature reports.32 All styrene substrates were dried over calcium
hydride, filtered, freeze−pump−thawed three times, and stored in a
nitrogen-filled glovebox. Pyridine was purchased from Acros, dried
over sodium metal, distilled under nitrogen, freeze−pump−thawed
three times, and stored in a nitrogen-filled glovebox.
(4-Methylphenethyl)diphenylphosphine Oxide (3b).
Characterization. All 1H NMR spectra were collected on either a
Varian Inova 600 MHz or a Bruker 600 MHz instrument and were
internally referenced to residual proton solvent signals for CDCl3 at δ
7.26 ppm. 13C{1H} NMR spectra were recorded on either a Varian
Inova 600 (151 MHz) or a Bruker 600 (151 MHz) instrument and
were also internally referenced at 77.00 ppm to deuterated
chloroform. Data for 1H NMR are reported as follows: chemical
shift (δ ppm), multiplicity (s = singlet, d = doublet, t = triplet, m =
multiplet), integration, and coupling constant (Hz). All 31P{1H}
NMR spectra were obtained from either a Varian Inova 600 (243
MHz) or a Varian VXRS 400 (162 MHz) instrument and were
externally referenced to 0.00 ppm with 85% H3PO4 in D2O. 19F{1H}
NMR spectra were recorded on a Varian VXRS 400 (376 MHz) and
were externally referenced to CFCl3 at 0.00 ppm. Infrared spectra
were collected on a PerkinElmer FT-IR spectrophotometer and are
reported in terms of wavenumber of absorption (cm−1). High-
resolution mass spectra were obtained on a Waters Synapt High
Definition Mass Spectrometer (HDMS) by electrospray ionization at
the University of Toledo. Melting points were determined in capillary
tubes using a capillary melting point apparatus.
General Procedure for the Catalytic Hydrophosphinylation
of Styrenes. In the glovebox, an oven-dried 20 mL vial was charged
with α-La(DMBA)3 (13.6 mg, 0.0250 mmol), diphenylphosphine
oxide (131 mg, 0.650 mmol), and pyridine (1 mL). Then the styrene
(0.5 mmol) was added to that mixture, and the vial was taken out of
the glovebox. The vial was placed in an 80 °C oil bath, where the
mixture was stirred for 16 h. Then, the pyridine was removed under
reduced pressure to afford crude β-arylphosphine oxide. Each was
then purified by either method A or method B.
White solid (90 mg, 56%). 1H NMR (600 MHz, CDCl3): δ 7.76 (dd,
3JH−P = 10.8 Hz, 3JH−H = 7.8 Hz, 4H), 7.55−7.43 (m, 6H), 7.09−7.03
(m, 4H), 2.92−2.84 (m, 2H), 2.60−2.52 (m, 2H), 2.29 (s, 3H).
13C{1H} NMR (151 MHz, CDCl3): δ 138.0 (d, JP−C = 16.2 Hz),
135.8, 132.7 (d, JP−C = 98.6 Hz), 131.7 (d, JP−C = 2.3 Hz), 130.7 (d,
J
P−C = 9.2 Hz), 129.2, 128.6 (d, JP−C = 11.4 Hz), 127.8, 32.0 (d, JP−C
= 69.7 Hz), 27.0 (d, JP−C = 3.5 Hz), 20.9. 31P{1H} NMR (243 MHz,
CDCl3): δ 31.7. This compound is known in the literature.16,33
(4-(tert-Butyl)phenethyl)diphenylphosphine Oxide (3c).
1
White solid (133 mg, 73%). H NMR (600 MHz, CDCl3): δ 7.76
(dd, 3JH−P = 10.8 Hz, 3JH−H = 7.8 Hz, 4H), 7.54−7.44 (m, 6H), 7.28
(d, 3JH−H = 8.4 Hz, 2H), 7.10 (d, 3JH−H = 8.4 Hz, 2H), 2.96−2.87 (m,
2H), 2.63−2.54 (m, 2H), 1.29 (s, 9H). 13C{1H} NMR (151 MHz,
CDCl3): δ 149.1, 138.0 (d, JP−C = 15.6 Hz), 132.7 (d, JP−C = 98.6
Hz), 131.7 (d, JP−C = 2.3 Hz), 130.7 (d, JP−C = 9.2 Hz), 128.6 (d, JP−C
= 11.5 Hz), 127.7, 125.4, 34.3, 31.8 (d, JP−C = 69.8 Hz), 31.3, 26.9 (d,
JP−C = 2.9 Hz). 31P{1H} NMR (243 MHz, CDCl3): δ 31.7. This
compound is known in the literature.16
(3-Methoxyphenethyl)diphenylphosphine Oxide (3d).
Purification Method A. The crude reaction product was extracted
with dichloromethane (5 mL) and filtered through a Celite pad in a
small pipet. The solvent was removed under reduced pressure, and the
residue was triturated with hexane, causing a precipitate to form. The
precipitate was then washed with cold diethyl ether and recrystallized
from dichloromethane to afford the pure β-arylphosphine oxide.
Compounds 3a,d,g−k,o−w were purified using this method.
Purification Method B. The crude reaction product was extracted
with dichloromethane (5 mL) and filtered through a Celite pad in a
small pipet. The residue was then purified by flash chromatography on
silica using ethyl acetate/hexane (3/7 to 10/0) as eluent. Compounds
3b,c,e,f,l−n were purified using this method.
1
White solid (158 mg, 94%). H NMR (600 MHz, CDCl3): δ 7.76
(dd, 3JH−P = 10.8 Hz, 3JH−H = 7.8 Hz, 4H), 7.55−7.43 (m, 6H), 7.17
(t, 3JH−H = 7.8 Hz, 1H), 6.77−6.68 (m, 3H), 3.75 (s, 3H), 2.94−2.85
(m, 2H), 2.62−2.53 (m, 2H). 13C{1H} NMR (151 MHz, CDCl3): δ
159.6, 142.7 (d, JP−C = 15.4 Hz), 132.6 (d, JP−C = 98.6 Hz), 131.7 (d,
J
P−C = 2.9 Hz), 130.7 (d, JP−C = 9.2 Hz), 129.5, 128.6 (d, JP−C = 11.5
Hz), 120.3, 113.7, 111.5, 55.1, 31.7 (d, JP−C = 70.4 Hz), 27.5 (d, JP−C
= 2.9 Hz). 31P{1H} NMR (243 MHz, CDCl3): δ 31.6. IR (cm−1):
3045.12 (w), 2948.70 (w), 1585.55 (m), 1486.84 (m), 1435.49 (s),
1252.89 (m), 1179.86 (s), 1152.63 (s), 1119.50 (s), 1039.99 (s),
993.46 (m), 936.97 (m), 897.07 (m), 804.42 (m), 773.85 (s), 731.45
(s), 694.20 (s), 563.55 (s), 508.35 (s). Mp: 132−133 °C. HRMS
(ESI): m/z calcd for C21H22O2P [(M + H)+] 337.1357, found
337.1358.
Characterization of Products. Phenethyldiphenylphosphine
Oxide (3a).
(4-Methoxyphenethyl)diphenylphosphine Oxide (3e).
1
White solid (141 mg, 92%). H NMR (600 MHz, CDCl3): δ 7.78
(dd, 3JH−P = 10.8 Hz, 3JH−H = 7.8 Hz, 4H), 7.56−7.45 (m, 6H), 7.29−
7.23 (m, 2H), 7.21−7.13 (m, 3H), 2.97−2.90 (m, 2H), 2.63−2.55
(m, 2H). 13C{1H} NMR (151 MHz, CDCl3): δ 141.1 (d, JP−C = 15.6
Hz), 132.7 (d, JP−C = 98.0 Hz), 131.7 (d, JP−C = 2.4 Hz), 130.7 (d,
JP−C = 9.2 Hz), 128.7, 128.6 (d, JP−C = 11.5 Hz), 128.0, 126.3, 31.8
(d, JP−C = 69.7 Hz), 27.5 (d, JP−C = 2.9 Hz). 31P{1H} NMR (243
MHz, CDCl3): δ 31.7. This compound is known in the
literature.14−16,33
White solid (94 mg, 56%). 1H NMR (600 MHz, CDCl3): δ 7.75 (dd,
3
3JH−P = 10.8 Hz, JH−H = 8.4 Hz, 4H), 7.54−7.42 (m, 6H), 7.06 (d,
3
3JH−H = 8.4 Hz, 2H), 6.78 (d, JH−H = 8.4 Hz, 2H), 3.74 (s, 3H),
2.91−2.82 (m, 2H), 2.59−2.49 (m, 2H). 13C{1H} NMR (151 MHz,
CDCl3): δ 158.0, 133.0 (d, JP−C = 15.6 Hz), 132.6 (d, JP−C = 98.6
Hz), 131.7 (d, JP−C = 2.9 Hz), 130.6 (d, JP−C = 9.2 Hz), 128.9, 128.6
(d, JP−C = 11.5 Hz), 114.0, 55.1, 32.0 (d, JP−C = 69.7 Hz), 26.5 (d,
E
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JP−C = 2.9 Hz). 31P{1H} NMR (243 MHz, CDCl3): δ 31.8. This
compound is known in the literature.15,16,33
(4-Nitrophenethyl)diphenylphosphine Oxide (3f).
8.4 Hz, 2H), 2.92−2.84 (m, 2H), 2.58−2.49 (m, 2H). 13C{1H} NMR
(151 MHz, CDCl3): δ 140.0 (d, JP−C = 15.6 Hz), 132.5 (d, JP−C
=
98.0 Hz), 131.8 (d, JP−C = 2.3 Hz), 131.5, 130.7 (d, JP−C = 9.2 Hz),
129.8, 128.7 (d, JP−C = 11.5 Hz), 120.0, 31.6 (d, JP−C = 70.3 Hz), 27.0
(d, JP−C = 2.9 Hz). 31P{1H} NMR (243 MHz, CDCl3): δ 31.4. This
compound is known in the literature.16
(3-Bromophenethyl)diphenylphosphine Oxide (3j).
1
Yellow-white solid (90 mg, 51%). H NMR (600 MHz, CDCl3): δ
8.08 (d, 3JH−H = 8.4 Hz, 2H), 7.75 (dd, 3JH−P = 11.4 Hz, 3JH−H = 7.8
3
Hz, 4H), 7.56−7.51 (m, 2H), 7.50−7.45 (m, 4H), 7.31 (d, JH−H
=
8.4 Hz, 2H), 3.08−3.01 (m, 2H), 2.62−2.55 (m, 2H). 13C{1H} NMR
(151 MHz, CDCl3): δ 148.7 (d, JP−C = 13.7 Hz), 146.5, 132.2 (d, JP−C
= 99.7 Hz), 132.0 (d, JP−C = 2.4 Hz), 130.7 (d, JP−C = 9.2 Hz), 129.0,
128.8 (d, JP−C = 11.5 Hz), 123.8, 31.2 (d, JP−C = 70.2 Hz), 27.5 (d,
JP−C = 3.5 Hz). 31P{1H} NMR (243 MHz, CDCl3): δ 31.0. IR
(cm−1): 3055.50 (w), 2901.68 (w), 1595.34 (m), 1511.39 (s),
1435.37 (m), 1346.67 (s), 1191.97 (s), 1119.58 (s), 1102.75 (s),
850.00 (m), 808.92 (m), 750.11 (s), 740.31 (s), 717.57 (s), 693.10
(s), 640.62 (s), 536.37 (s), 509.45 (s), 473.05 (s). Mp: 133−135 °C.
HRMS (ESI): m/z calcd for C20H19NO3P [(M + H)+] 352.1103,
found 352.1111.
1
White solid (170 mg, 92%). H NMR (600 MHz, CDCl3): δ 7.76
(dd, 3JH−P = 11.4 Hz, 3JH−H = 7.8 Hz, 4H), 7.56−7.51 (m, 2H), 7.51−
7.45 (m, 4H), 7.32−7.28 (m, 2H), 7.14−7.07 (m, 2H), 2.94−2.87
(m, 2H), 2.59−2.52 (m, 2H). 13C{1H} NMR (151 MHz, CDCl3): δ
143.4 (d, JP−C = 15.1 Hz), 132.5 (d, JP−C = 98.6 Hz), 131.9 (d, JP−C
=
2.3 Hz), 131.1, 130.7 (d, JP−C = 9.2 Hz), 130.1, 129.4, 128.7 (d, JP−C
= 11.5 Hz), 126.8, 122.5, 31.6 (d, JP−C = 70.3 Hz), 27.2 (d, JP−C = 2.9
Hz). 31P{1H} NMR (243 MHz, CDCl3): δ 31.3. This compound is
known in the literature.33
(4-Fluorophenethyl)diphenylphosphine Oxide (3g).
(2-Bromophenethyl)diphenylphosphine Oxide (3k).
1
White solid (130 mg, 80%). H NMR (600 MHz, CDCl3): δ 7.75
(dd, 3JH−P = 10.8 Hz, 3JH−H = 7.8 Hz, 4H), 7.55−7.44 (m, 6H), 7.10
(dd, 3JH−H = 7.8 Hz, 3JH−F= 6.0 Hz, 2H), 6.95−6.88 (m, 2H), 2.94−
2.86 (m, 2H), 2.59−2.51 (m, 2H). 13C{1H} NMR (151 MHz,
CDCl3): δ 161.4 (d, JF−C = 244.5 Hz), 136.7 (dd, JF−C = 3.5 Hz, JP−C
= 14.9 Hz), 132.6 (d, JP−C = 98.6 Hz), 131.8 (d, JP−C = 2.4 Hz), 130.7
(d, JP−C = 9.2 Hz), 129.4 (d, JF−C = 8.0 Hz), 128.7 (d, JP−C = 11.5
Hz), 115.3 (d, JF−C = 21.3 Hz), 31.9 (d, JP−C = 69.8 Hz), 26.7 (d, JP−C
= 2.9 Hz). 31P{1H} NMR (243 MHz, CDCl3): δ 31.4. 19F{1H} NMR
(376 MHz, CDCl3): δ −117.0. This compound is known in the
literature.15,16,33
1
White solid (165 mg, 89%). H NMR (600 MHz, CDCl3): δ 7.79
(dd, 3JH−P = 11.4 Hz, 3JH−3H = 7.8 Hz, 4H), 7.54−7.44 (m, 7H), 7.24−
7.16 (m, 2H), 7.04 (t, JH−H = 7.2 Hz, 1H), 3.08−2.98 (m, 2H),
2.64−2.53 (m, 2H). 13C{1H} NMR (151 MHz, CDCl3): δ 140.4 (d,
J
P−C = 15.6 Hz), 132.8, 132.5 (d, JP−C = 97.4 Hz), 131.7 (d, JP−C = 2.3
Hz), 130.7 (d, JP−C = 9.4 Hz), 130.4, 128.6 (d, JP−C = 11.6 Hz), 128.1,
127.7, 123.9, 30.0 (d, JP−C = 69.2 Hz), 28.5 (d, JP−C = 2.3 Hz).
31P{1H} NMR (243 MHz, CDCl3): δ 31.6. IR (cm−1): 3056.06 (w),
1470.76 (w), 1436.59 (m), 1177.96 (s), 1118.58 (m), 1099.37 (m),
996.44 (w), 775.44 (m), 740.86 (s), 712.51 (s), 692.24 (s), 656.87
(m), 589.82 (s), 532.41 (s), 517.83 (s), 504.33 (s), 495.20 (s). Mp:
82−83 °C. HRMS (ESI): m/z calcd for C20H19BrOP [(M + H)+]
385.0357, found 385.0371.
(4-Chlorophenethyl)diphenylphosphine Oxide (3h).
(2,3,4,5,6-Pentafluorophenethyl)diphenylphosphine Oxide (3l).
1
White solid (145 mg, 85%). H NMR (600 MHz, CDCl3): δ 7.75
(dd, 3JH−P = 10.8 Hz, 3JH−H = 7.8 Hz, 4H), 7.55−7.50 (m, 2H), 7.49−
7.44 (m, 4H), 7.20 (d, 3JH−H = 7.8 Hz, 2H), 7.07 (d, 3JH−H = 7.8 Hz,
2H), 2.94−2.85 (m, 2H), 2.58−2.49 (m, 2H). 13C{1H} NMR (151
MHz, CDCl3): δ 139.4 (d, JP−C = 14.9 Hz), 132.5 (d, JP−C = 98.6 Hz),
131.9, 131.8 (d, JP−C = 2.3 Hz), 130.6 (d, JP−C = 9.2 Hz), 129.4, 128.6
1
White solid (105 mg, 53%). H NMR (600 MHz, CDCl3): δ 7.79−
(d, JP−C = 11.5 Hz), 128.5, 31.6 (d, JP−C = 69.8 Hz), 26.9 (d, JP−C
=
7.72 (m, 4H), 7.56−7.51 (m, 2H), 7.50−7.45 (m, 4H), 3.06−3.00
(m, 2H), 2.58−2.51 (m, 2H). 13C{1H} NMR (151 MHz, CDCl3): δ
144.9 (dm, JF−C = 247.2 Hz), 139.9 (dm, JF−C = 252.2 Hz), 137.4
3.0 Hz). 31P{1H} NMR (243 MHz, CDCl3): δ 31.4. This compound
is known in the literature.16,33
(4-Bromophenethyl)diphenylphosphine Oxide (3i).
(dm, JF−C = 252.2 Hz), 132.1 (d, JP−C = 100.1 Hz), 132.0 (d, JP−C
=
2.3 Hz), 130.7 (d, JP−C = 8.8 Hz), 128.8 (d, JP−C = 11.0 Hz), 113.7
(m), 29.1 (d, JP−C = 70.5 Hz), 15.1. 31P{1H} NMR (243 MHz,
CDCl3): δ 30.5. 19F{1H} NMR (376 MHz, CDCl3): δ −143.5 (dd, J
= 22.8 Hz, 8.3 Hz), −157.0 (t, J = 20.5 Hz), −162.5 - −162.6 (m). IR
(cm−1): 2951.29 (w), 1520.65 (m), 1500.51 (s), 1436.30 (m),
1260.25 (m), 1182.69 (s), 1115.78 (s), 994.71 (s), 955.52 (s), 915.11
(s), 797.06 (s), 752.01 (s), 741.64 (s), 720.21 (s), 692.77 (s), 527.99
(s), 507.64 (s). Mp: 136−138 °C. HRMS (ESI): m/z calcd for
C20H15F5OP [(M + H)+] 397.0781, found 397.0793.
1
Yellow-white solid (170 mg, 92%). H NMR (600 MHz, CDCl3): δ
7.74 (dd, 3JH−P = 10.8 Hz, 3JH3−H = 7.8 Hz, 4H), 7.55−7.50 (m, 2H),
3
7.49−7.44 (m, 4H), 7.34 (d, JH−H = 8.4 Hz, 2H), 7.02 (d, JH−H
=
F
DOI: 10.1021/acs.organomet.9b00549
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Diphenyl(2-(pyridin-4-yl)ethyl)phosphine Oxide (3m).
13C{1H} NMR (151 MHz, CDCl3): δ 145.1 (d, JP−C = 17.2 Hz),
132.2 (d, JP−C = 98.5 Hz), 132.0 (d, JP−C = 2.4 Hz), 130.7 (d, JP−C
=
9.4 Hz), 128.8 (d, JP−C = 11.5 Hz), 127.3, 120.8, 109.1, 31.7 (d, JP−C
= 69.8 Hz), 22.2 (d, JP−C = 2.3 Hz). 31P{1H} NMR (243 MHz,
CDCl3): δ 30.8. IR (cm−1): 3116.00 (w), 3069.57 (w), 3055.03 (w),
2926.04 (w), 1526.38 (w), 1436.24 (s), 1200.88 (m), 1176.68 (s),
1158.65 (s), 1120.60 (s), 1096.08 (m), 1070.36 (m), 993.73 (m),
936.13 (m), 834.73 (m), 818.34 (m), 786.42 (m), 739.17 (s), 716.90
(s), 692.35 (s), 607.90 (s), 528.98 (s), 514.68 (s), 498.86 (s). Mp:
88−90 °C. HRMS (ESI): m/z calcd for C18H17BrOPS [(M + H)+]
390.9922, found 390.9929.
White solid (144 mg, 94%). 1H NMR (600 MHz, CDCl3): δ 8.46 (d,
3JH−H = 5.4 Hz, 2H), 7.76 (dd, 3JH−P = 11.4 Hz, 3JH−H = 7.8 Hz, 4H),
7.58−7.45 (m, 6H), 7.09 (d, JH−H = 5.4 Hz, 2H), 2.96−2.89 (m,
3
2H), 2.60−2.53 (m, 2H). 13C{1H} NMR (151 MHz, CDCl3): δ
149.9, 149.9 (d, JP−C = 14.9 Hz), 132.2 (d, JP−C = 99.7 Hz), 132.0 (d,
JP−C = 2.9 Hz), 130.7 (d, JP−C = 9.2 Hz), 128.8 (d, JP−C = 11.5 Hz),
123.4, 30.6 (d, JP−C = 70.2 Hz), 26.9 (d, JP−C = 2.9 Hz). 31P{1H}
NMR (243 MHz, CDCl3): δ 31.3. IR (cm−1): 3054.42 (w), 2930.29
(w), 1600.65 (m), 1560.01 (w), 1436.92 (m), 1171.16 (s), 1118.51
(s), 1100.47 (m), 992.73 (m), 942.70 (m), 806.81 (s), 774.75 (s),
744.42 (s), 733.57 (s), 715.57 (s), 692.23 (s), 586.93 (s), 536.94 (s),
508.13 (s), 490.62 (s). Mp: 114−116 °C. HRMS (ESI): m/z calcd for
C19H19NOP [(M + H)+] 308.1204, found 308.1207.
(2-(Benzo[d][1,3]dioxol-5-yl)ethyl)diphenylphosphine Oxide
(3q).
1
Diphenyl(2-(pyridin-2-yl)ethyl)phosphine Oxide (3n).
White solid (120 mg, 69%). H NMR (600 MHz, CDCl3): δ 7.75
(dd, 3JH−P = 10.8 Hz, 3JH−H = 8.4 Hz, 4H), 7.54−7.44 (m, 6H), 6.69−
6.57 (m, 3H), 5.89 (s, 2H), 2.90−2.79 (m, 2H), 2.58−2.48 (m, 2H).
13C{1H} NMR (151 MHz, CDCl3): δ 147.6, 145.9, 134.9 (d, JP−C
=
15.0 Hz), 132.7 (d, JP−C = 98.6 Hz), 131.7 (d, J P−C = 2.4 Hz), 130.7
(d, JP−C = 9.2 Hz), 128.7 (d, JP−C = 11.5 Hz), 120.8, 108.5, 108.3,
100.8, 32.1 (d, JP−C = 69.2 Hz), 27.3 (d, JP−C = 2.9 Hz). 31P{1H}
NMR (243 MHz, CDCl3): δ 31.5. IR (cm−1): 3051.54 (w), 2892.92
(w), 1608.69 (w), 1503.32 (m), 1489.78 (m), 1436.84 (m), 1247.99
(m), 1176.46 (s), 1132.31 (m), 1119.11 (m), 1038.60 (m), 934.03
(m), 785.26 (m), 746.24 (m), 716.04 (m), 693.16 (s), 547.42 (s),
513.56 (s), 494.38 (s). Mp: 136−138 °C. HRMS (ESI): m/z calcd for
C21H20O3P [(M + H)+] 351.1150, found 351.1152.
White solid (150 mg, 98%). 1H NMR (600 MHz, CDCl3): δ 8.48 (d,
3JH−H = 4.8 Hz, 1H), 7.77 (dd, 3JH−P = 11.4 Hz, 3JH−H = 7.2 Hz, 4H),
3
3
7.56−7.39 (m, 7H), 7.11 (d, JH−H = 7.8 Hz, 1H), 7.07 (dd, JH−H
=
7.2 Hz, 3JH−H = 4.8 Hz, 1H), 3.14−3.06 (m, 2H), 2.82−2.73 (m, 2H).
13C{1H} NMR (151 MHz, CDCl3): δ 160.0 (d, JP−C = 14.9 Hz),
149.1, 136.3, 132.6 (d, JP−C = 98.6 Hz), 131.6 (d, JP−C = 2.3 Hz),
130.7 (d, JP−C = 9.2 Hz), 128.5 (d, JP−C = 11.5 Hz), 123.0, 121.3, 29.6
(d, JP−C = 2.9 Hz), 29.0 (d, JP−C = 71.4 Hz). 31P{1H} NMR (243
MHz, CDCl3): δ 32.4. This compound is known in the literature.16,33
(2-(Furan-2-yl)ethyl)diphenylphosphine Oxide (3o).
(2-(Naphthalen-2-yl)ethyl)diphenylphosphine Oxide (3r).
1
White solid (148 mg, 83%). H NMR (600 MHz, CDCl3): δ 7.84−
7.72 (m, 7H), 7.59 (s, 1H), 7.54−7.39 (m, 8H), 7.30 (d, 3JH−H = 8.4
Hz, 1H), 3.16−3.07 (m, 2H), 2.71−2.64 (m, 2H). 13C{1H} NMR
(151 MHz, CDCl3): δ 138.5 (d, JP−C = 14.9 Hz), 133.4, 132.7 (d, JP−C
= 98.5 Hz), 132.0, 131.7 (d, JP−C = 2.3 Hz), 130.7 (d, JP−C = 9.2 Hz),
128.6 (d, JP−C = 11.5 Hz), 128.2, 127.5, 127.3, 126.6, 126.1, 126.0,
125.4, 31.7 (d, JP−C = 69.8 Hz), 27.6 (d, JP−C = 2.9 Hz). 31P{1H}
NMR (243 MHz, CDCl3): δ 31.7. This compound is known in the
literature.15
1
White solid (125 mg, 84%). H NMR (600 MHz, CDCl3): δ 7.79−
7.70 (m, 4H), 7.55−7.43 (m, 6H), 7.24 (dd, 3JH−H = 1.8 Hz, 4JH−H
=
0.6 Hz, 1H), 6.21 (dd, 3JH−H = 3.0 Hz, 3JH−H = 1.8 Hz, 1H), 5.97 (dd,
3JH−H = 3.0 Hz, 4JH−H = 0.6 Hz, 1H), 3.00−2.90 (m, 2H), 2.67−2.55
(m, 2H). 13C{1H} NMR (151 MHz, CDCl3): δ 154.0 (d, JP−C = 16.8
Hz), 141.2, 132.3 (d, JP−C = 98.6 Hz), 131.8 (d, JP−C = 2.4 Hz), 130.6
(d, JP−C = 9.2 Hz), 128.6 (d, JP−C = 11.6 Hz), 110.2, 105.4, 28.3 (d,
JP−C = 70.8 Hz), 20.3 (d, JP−C = 2.4 Hz). 31P{1H} NMR (243 MHz,
CDCl3): δ 31.5. IR (cm−1): 3441.01 (w), 3050.67 (w), 2907.33 (w),
1436.48 (s), 1167.90 (s), 1142.74 (s), 1118.04 (s), 1069.42 (m),
1046.01 (m), 994.79 (m), 910.10 (s), 818.58 (m), 790.80 (m),
763.63 (s), 733.21 (s), 721.89 (s), 694.96 (s), 598.41 (m), 556.99 (s),
524.74 (s), 510.92 (s), 480.95 (s). Mp: 74−76 °C. HRMS (ESI): m/z
calcd for C18H18O2P [(M + H)+] 297.1044, found 297.1044.
Phenethyldi-p-tolylphosphine Oxide (3s).
(2-(4-Bromothiophen-2-yl)ethyl)diphenylphosphine Oxide (3p).
White solid (67 mg, 80%). 1H NMR (600 MHz, CDCl3): δ 7.62 (dd,
3JH−P = 11.4 Hz, 3JH−H = 8.4 Hz, 4H), 7.29−7.21 (m, 6H), 7.18−7.11
(m, 3H), 2.93−2.84 (m, 2H), 2.55−2.48 (m, 2H), 2.37 (s, 6H).
13C{1H} NMR (151 MHz, CDCl3): δ 142.2 (d, JP−C = 2.4 Hz), 141.3
(d, JP−C = 15.6 Hz), 130.7 (d, JP−C = 9.7 Hz), 129.4 (d, JP−C = 100.9
1
Hz), 129.4 (d, JP−C = 12.2 Hz), 128.5, 128.0, 126.2, 31.9 (d, JP−C
=
White solid (156 mg, 80%). H NMR (600 MHz, CDCl3): δ 7.74
70.4 Hz), 27.5 (d, JP−C = 2.9 Hz), 21.5. 31P{1H} NMR (243 MHz,
CDCl3): δ 32.3. This compound is known in the literature.15,16,33
(dd, 3JH−P = 10.8 Hz, 3JH−H = 7.8 Hz, 4H), 7.59−7.43 (m, 6H), 6.98
(s, 1H), 6.68 (s, 1H), 3.17−3.04 (m, 2H), 2.67−2.55 (m, 2H).
G
DOI: 10.1021/acs.organomet.9b00549
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
Bis(4-methoxyphenyl)(phenethyl)phosphine Oxide (3t).
(ESI): m/z calcd for C24H28O5P [(M + H)+] 427.1674, found
427.1680.
Bis(naphthalen-2-yl)(phenethyl)phosphine Oxide (3w).
1
White solid (173 mg, 95%). H NMR (600 MHz, CDCl3): δ 7.67
(dd, 3JH−P = 10.8 Hz, 3JH−H = 8.4 Hz, 4H), 7.28−7.24 (m, 2H), 7.20−
7.12 (m, 3H), 6.97 (d, 3JH−H = 7.2 Hz, 4H), 3.84 (s, 6H), 2.96−2.85
(m, 2H), 2.57−2.47 (m, 2H). 13C{1H} NMR (151 MHz, CDCl3): δ
162.1 (d, JP−C = 2.3 Hz), 141.2 (d, JP−C = 15.7 Hz), 132.5 (d, JP−C
=
White solid (155 mg, 76%). 1H NMR (600 MHz, CDCl3): δ 8.48 (d,
11.0 Hz), 128.4, 127.9, 126.1, 123.8 (d, JP−C = 105.5 Hz), 114.3,
114.2, 114.1 (d, JP−C = 12.7 Hz), 55.2, 32.1 (d, JP−C = 70.8 Hz), 27.5
(d, JP−C = 2.9 Hz). 31P{1H} NMR (243 MHz, CDCl3): δ 31.7. IR
(cm−1): 3010.66 (w), 2935.24 (w), 2832.88 (w), 1594.22 (s),
1569.76 (m), 1499.78 (s), 1462.54 (m), 1293.89 (m), 1254.31 (s),
1169.56 (s), 1116.38 (s), 1101.76 (s), 1021.19 (s), 932.28 (m),
817.69 (s), 799.09 (s), 770.32 (m), 742.79 (s), 696.80 (s), 654.35
(m), 575.89 (s), 526.03 (s), 500.11 (s). Mp: 95−98 °C. HRMS
(ESI): m/z calcd for C22H24O3P [(M + H)+] 367.1463, found
367.1468.
3
3JH−P = 13.2 Hz, 2H), 7.96−7.88 (m, 4H), 7.85 (d, JH−H = 7.8 Hz,
2H), 7.73 (t, 3JH−H = 9.0 Hz, 2H), 7.58−7.51 (m, 4H), 7.28−7.22 (m,
2H), 7.21−7.13 (m, 3H), 3.11−2.92 (m, 2H), 2.85−2.69 (m, 2H).
13C{1H} NMR (151 MHz, CDCl3): δ 141.1 (d, JP−C = 15.0 Hz),
134.6 (d, JP−C = 2.3 Hz), 132.8 (d, JP−C = 8.0 Hz), 132.5 (d, JP−C
=
12.7 Hz), 130.2 (d, JP−C = 98.6 Hz), 128.8, 128.7 (d, JP−C = 11.6 Hz),
128.6, 128.1, 128.0, 127.8, 127.0, 126.3, 125.5 (d, JP−C = 10.4 Hz),
31.7 (d, JP−C = 70.4 Hz), 27.6 (d, JP−C = 2.9 Hz). 31P{1H} NMR (243
MHz, CDCl3): δ 32.0. This compound is known in the literature.15,33
Bis(4-tert-butylphenyl)(phenethyl)phosphine Oxide (3u).
ASSOCIATED CONTENT
* Supporting Information
■
S
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.organo-
met.9b00549.
NMR spectra for all hydrophosphinylation products
(3a−w) (PDF)
1
White solid (193 mg, 92%). H NMR (600 MHz, CDCl3): δ 7.70
(dd, 3JH−P = 10.8 Hz, 3JH−H = 8.4 Hz, 4H), 7.52−7.44 (m, 4H), 7.28−
7.22 (m, 2H), 7.20−7.13 (m, 3H), 3.02−2.87 (m, 2H), 2.63−2.49
(m, 2H), 1.32 (s, 18H). 13C{1H} NMR (151 MHz, CDCl3): δ 155.0
(d, JP−C = 2.7 Hz), 141.3 (d, JP−C = 15.6 Hz), 130.7 (d, JP−C = 9.2
AUTHOR INFORMATION
Corresponding Author
*J.A.R.S.: e-mail, Joseph.Schmidt@utoledo.edu; tel, 419-530-
1512; fax, 419-530-4033.
■
Hz), 129.6 (d, JP−C = 99.7 Hz), 128.4, 128.0, 126.1, 125.6 (d, JP−C
=
12.1 Hz), 34.9, 32.0 (d, JP−C = 70.2 Hz), 31.0, 27.5 (d, JP−C = 3.3 Hz).
31P{1H} NMR (243 MHz, CDCl3): δ 31.5. IR (cm−1): 3026.99 (w),
2961.45 (w), 2866.62 (w), 1599.95 (w), 1496.31 (w), 1392.52 (w),
1362.06 (w), 1267.99 (w), 1178.90 (s), 1112.17 (m), 1092.71 (m),
835.42 (m), 773.78 (m), 757.18 (m), 724.41 (m), 697.16 (m),
611.71 (s), 591.12 (m), 562.83 (m), 555.24 (m), 507.10 (m), 488.92
(m), 472.85 (m). Mp: 227−230 °C. HRMS (ESI): m/z calcd for
C28H36OP [(M + H)+] 419.2504, found 419.2512.
ORCID
Joseph A. R. Schmidt: 0000-0003-3019-0055
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
Bis(3,5-dimethoxyphenyl)(phenethyl)phosphine Oxide (3v).
Acknowledgement is made to the Donors of the American
Chemical Society Petroleum Research Fund for support of this
research.
REFERENCES
■
(1) (a) Quin, L. D. A guide to organophosphorus chemistry; Wiley:
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1
White solid (176 mg, 83%). H NMR (600 MHz, CDCl3): δ 7.28−
7.23 (m, 2H), 7.21−7.14 (m, 3H), 6.84 (dd, 3JH−P = 13.2 Hz, 4JH−H
=
2.4 Hz, 4H), 6.57 (s, 2H), 3.80 (s, 12 H), 3.01−2.89 (m, 2H), 2.59−
2.47 (m, 2H). 13C{1H} NMR (151 MHz, CDCl3): δ 160.9 (d, JP−C
=
2004, 248, 955−993. (b) Dominelli, B.; Correia, J. D. G.; Kuhn, F. E.
̈
17.4 Hz), 141.1 (d, JP−C = 15.7 Hz), 134.6 (d, JP−C = 98.0 Hz), 128.5,
128.0, 126.3, 108.2 (d, JP−C = 11.0 Hz), 103.8 (d, JP−C = 1.8 Hz),
55.5, 31.8 (d, JP−C = 70.4 Hz), 27.5 (d, JP−C = 2.9 Hz). 31P{1H} NMR
(243 MHz, CDCl3): δ 32.8. IR (cm−1): 2992.58 (w), 2934.20 (w),
2833.51 (w), 1582.23 (s), 1450.68 (m), 1417.61 (s), 1336.50 (m),
1284.55 (s), 1204.50 (s), 1172.88 (s), 1152.42 (s), 1059.98 (s),
987.45 (m), 841.78 (s), 756.43 (m), 741.34 (s), 693.87 (s), 605.33
(s), 578.26 (m), 510.09 (m), 469.06 (s). Mp: 105−107 °C. HRMS
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