Palladium-catalyzed coupling reactions of bromo-substituted phenylphosphine oxides: A facile route to functionalized arylphosphine ligands

Article abstract of DOI:10.1016/S0022-328X(03)00663-6

The Heck reaction of OPPh_3-n(4-C₆H₄Br) _n (n=1-3) with electron deficient and neutral olefins led to linear olefin-substituted phenylphosphine oxides, whilst the reaction with an electron rich olefin in an ionic liquid solvent resulted in the formation of acetyl variants. The same bromophenylphosphine oxides also reacted with arylboronic acids under normal Suzuki coupling conditions, affording arylated phenylphosphine oxides in excellent yields. Amination and methoxycarbonylation of the bromophenylphosphine oxides by palladium catalysis were also shown to be feasible. Given that free phosphines can be readily derived from phosphine oxides, palladium-catalyzed coupling of OPR_3-n(C₆H₄Br)_n (R=alkyl, aryl) should provide a simple, yet versatile, route to functionalized phosphine ligands.

Full text of DOI:10.1016/S0022-328X(03)00663-6

Journal of Organometallic Chemistry 687 (2003) 301ꢂ312
/
www.elsevier.com/locate/jorganchem
Palladium-catalyzed coupling reactions of bromo-substituted
phenylphosphine oxides: a facile route to functionalized
arylphosphine ligands
Lijin Xu, Jun Mo, Colin Baillie, Jianliang Xiao *
Leverhulme Centre for Innovative Catalysis, Department of Chemistry, University of Liverpool, Liverpool L69 7ZD, UK
Received 16 May 2003; accepted 30 June 2003
Dedicated to Professor J.P. Geneˆt for his significant contributions to the art of organic synthesis
Abstract
The Heck reaction of OPPh3ꢀn(4-C6H4Br)n (nꢁ
/
1ꢂ3) with electron deficient and neutral olefins led to linear olefin-substituted
/
phenylphosphine oxides, whilst the reaction with an electron rich olefin in an ionic liquid solvent resulted in the formation of acetyl
variants. The same bromophenylphosphine oxides also reacted with arylboronic acids under normal Suzuki coupling conditions,
affording arylated phenylphosphine oxides in excellent yields. Amination and methoxycarbonylation of the bromophenylphosphine
oxides by palladium catalysis were also shown to be feasible. Given that free phosphines can be readily derived from phosphine
oxides, palladium-catalyzed coupling of OPR3ꢀn(C6H4Br)n (Rꢁalkyl, aryl) should provide a simple, yet versatile, route to
/
functionalized phosphine ligands.
# 2003 Elsevier B.V. All rights reserved.
Keywords: Phosphine oxides; Phosphines; Coupling reactions; Palladium catalysis
1. Introduction
and efficiently [4]. For instance, transition metal cata-
C cross coupling has been developed and
shown to provide a very useful approach in phosphine
lyzed PÃ
/
Aryl phosphines have been widely employed as highly
efficient ligands for various transformations in homo-
geneous catalysis and asymmetric synthesis [1]. The
functionalities on the aryl groups are of particular
relevance to catalytic reactions and can serve as a
handle for solubility enhancement or attachment onto
solids [1,2]. However, the commercial availability of aryl
phosphines in terms of structural diversity is limited and
there is no simple route to these functionalities.
Attempts to achieve functionalization via traditional
methods prove difficult due to the poor functional
tolerance and the use of moisture- or air-sensitive
reagents [3]. In recent years, catalytic methods have
emerged, allowing a variety of structurally and electro-
nically diverse phosphines to be accessed more easily
synthesis. Thus, phosphines can be prepared by coupling
phosphorus substrates containing a PÃ
/
X bond (Xꢁ
/
H,
SnMe3, Cl, SiR3) with aryl and vinyl halides [5ꢂ
/
9]. More
recently, the palladium-catalyzed phosphination of aryl
bromides using triarylphosphines as the phosphinating
agents has been described; the reaction proceeds with
good functional group tolerance but suffers from low
yields [10].
Palladium-catalyzed CÃ
/
C coupling reactions have
widely been used in organic synthesis, and offer an
easy access to functionalized arenes [11]. However, this
efficient methodology has received less attention in the
catalytic synthesis of functionalized phosphines. In
1997, Trost and co-workers first described the functio-
nalization of triphenylphosphine via palladium-cata-
lyzed
CÃ/C
coupling
reactions
[12].
A
bromotriarylphosphine or its oxide was used as a
starting block to couple with terminal alkynes and
* Corresponding author. Tel./fax: ꢃ44-151-794-2937.
E-mail address: j.xiao@liv.ac.uk (J. Xiao).
/
0022-328X/03/$ - see front matter # 2003 Elsevier B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00663-6

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L. Xu et al. / Journal of Organometallic Chemistry 687 (2003) 301ꢂ312
/
arylboronic acids. It was observed that in the presence
of Pd(PPh3)4, the Suzuki coupling of bromoarylpho-
sphines with phenylboronic acid was sluggish and
incomplete due to possible catalyst poisoning. With
the corresponding phosphine oxide, however, the Suzuki
reaction proceeded smoothly to give the product in high
yield. Obviously, the phosphine oxide is advantageous
over its free form due to its stability and less likelihood
for coordination. The strong electron-withdrawing ef-
fect of the phosphoryl moiety should not be overlooked,
however (vide infra). Similar observations were made in
the coupling reactions with terminal alkynes. After
reduction with HSiCl3, the functionalized arylphos-
phines were obtained in high yields. Focusing their
research on polymer-supported catalysts, Pu and his co-
workers synthesized polymer-supported BINAP via the
Suzuki coupling of a chiral binaphthyl monomer with
dibromobenzene followed by HSiCl3 reduction [13].
Buchwald and co-worker described an efficient asym-
metric Suzuki cross coupling for the synthesis of new
chiral phosphine ligands in high yields and excellent ee
values [14]. More recently, palladium-catalyzed Suzuki
coupling has been employed by Zhang and co-workers
2. Results and discussion
2.1. Synthesis of functionalized arylphosphine oxides by
the Heck reaction
The Heck reaction provides a powerful CÃ
/
C bond
forming process in organic synthesis, permitting the
coupling of aryl/vinyl halides with a wide array of
olefins and introducing an ethylene spacer between the
aromatic/vinylic units and substituents at the CÄ
/C
double bond. In our initial study, we found that tris(4-
bromophenyl)phosphine failed to couple with n-butyl
acrylate under normal Heck conditions with the
HerrmannꢂBeller palladacycle [18] as catalyst in N,N-
/
dimethylformamide (DMF) at 120 8C for 24 h, possibly
partly due to poisoning of active palladium species by
the excessive phosphine. Whilst borane protected pri-
mary or secondary phosphines have been employed in
the synthesis of phosphine ligands [7], the borane-
protected tris(4-bromophenyl)phosphine did not react
with n-butyl acrylate. Because the presence of electron
withdrawing groups can facilitate the oxidative addition
of aryl halides to active Pd(0) species and the PÄ
/O
moiety exhibits a strong electron withdrawing effect [3],
we attempted the Heck reaction of tris(4-chlorophen-
yl)phosphine oxide with n-butyl acrylate using the
palladacycle in DMF at 130 8C for 36 h. Unfortunately,
we were unable to obtain a reasonable yield of
olefinated phosphine oxide. Even under more forcing
conditions, including longer reaction time, higher tem-
perature and increased loading of catalysts, only a very
low conversion was observed, suggesting that the
palladacycle catalyst is not active enough towards the
to prepare
a
multi-substituted BIPHEP ligand
[BIPHEPꢁ2,2?-bis(diphenylphosphino)biphenyl] [15].
/
Treatment of an iodo-substituted arylphosphine oxide
with phenylboronic acid in the presence of Pd(PPh3)4 led
to the formation of a phenyl-substituted arylphosphine
oxide. The subsequent copper-mediated Ullmann cou-
pling furnished the BIPHEP ligand in good yield. In
addition to Suzuki coupling, the Heck and Stille
reactions have been applied to the synthesis of phos-
phorus compounds [16].
CÃ
/
Cl bond under the conditions employed.
1
A previous H-NMR study indicated that the elec-
tron-withdrawing effect of the phosphoryl group on the
para position of a phenyl ring lies between those of a
We previously reported a simple and high-yield
method for a variety of functionalized arylphosphines
by palladium-catalyzed CÃ/C coupling reactions [17].
carbonyl and a bromide group [19], and so a PÄ
substituted phenyl bromide could behave like an acti-
vated aryl bromide in the Heck reaction. Indeed, the
/O
With the easily available haloarylphosphine oxides
OPPh3ꢀn(4-C6H4Br)n as starting material, phosphines
bearing fluoroalkylated chains with CH2CH2 spacers,
and the alkyl variants including those containing
carboxylate groups were synthesized by the Heck
arylation of the corresponding olefins; these phosphines
can be used as ligands for catalysis in supercritical CO2,
fluorous solvents as well as water. The methodology was
further extended to the preparation of functionalized
biphenyl phosphines via the Suzuki coupling of OP-
Ph2(o-C6H4Br) with various arylboronic acids [17c]. In
an attempt to determine if palladium catalysis could be
applied to the preparation of a wider range of phos-
phines that may find use in catalysis and organometallic
chemistry, we undertook a broader investigation into
the palladium-catalyzed reaction of OPPh3ꢀn(4-
C6H4Br)n. The results are briefly summarized in Scheme
1 and presented in detail below.
oxides 1aꢂ/c could be easily olefinated with a variety of
olefins CH2Ä
/
CHÃR (Rꢁbutoxycarbonyl, cyano, n-
/
/
alkyl, phenyl, 4-chlorophenyl). In a typical coupling
reaction, a phosphine oxide was mixed with 1.5 equiva-
lent of an olefin (relative to Br), ca. 1.3 equivalent of
NaOAc, and 0.5 mol% of palladacycle catalyst in DMF.
The coupling reaction proceeded smoothly at 125 or
130 8C to give the olefinated phosphine oxides 2aꢂ
high isolated yields (Table 1). Most of the reactions went
to completion in 24ꢂ30 h reaction time regardless of the
/k in
/
number of bromide substitutes in the starting oxide and
the nature of olefins. As expected, in the case of n-butyl
acrylate, styrene and 4-chlorostyrene, substitution of the
vinylic protons by the arylphosphine oxides occurred at
b carbon of the CÄ
/
C double bonds leading to trans
olefins. With acrylonitrile as an olefinating reagent, a

L. Xu et al. / Journal of Organometallic Chemistry 687 (2003) 301ꢂ
/
312
303
Scheme 1.
higher reaction temperature and longer reaction time
was required, and the main products were trans olefins
with cis isomers amounting to about 5ꢂ10% as judged
The Heck reaction can also be extended to the
arylation of n-butyl vinyl ether with the phosphine
oxides. It has been known that with electron-rich acyclic
olefins such as enol ethers and enamides, mixtures of
regioisomers usually result under normal Heck arylation
conditions, due to competing neutral and ionic reaction
pathways with one leading to a and the other to b
substitution [21]. We recently found that highly regio-
selective arylation of n-butyl vinyl ether could be readily
achieved with palladium catalysis when the reaction was
carried out in an ionic liquid, 1-butyl-3-methylimidazo-
lium tetrafluoroborate ([bmim][BF4]); the reaction uses
aryl halides instead of the commonly used, but commer-
cially unavailable aryl triflates [22]. More recently,
Hallberg and co-workers reported that similar reactions
/
by the 1H-NMR spectra. Previously, [Pd(OAc)2{P(o-
Tol)3}2], a precursor to the palladacycle [18], was shown
to be highly active in catalyzing the coupling of
acrylonitrile with 4-bromobenzaldehyde [20]; but the
study also showed the reaction to be strongly substrate-
dependent, with electron-withdrawing substituents fa-
voring faster rates, suggesting that the CÃ
/
Br bond in 1
may not be as activated as that in 4-bromobenzalde-
hyde. Regioisomers were also produced with the more
electron-rich 1-alkenes, where 10% of the product was
generated from 2-substitution according to NMR inte-
gration.
Table 1
Heck coupling of OPPh3ꢀn (4-C6H4Br)n with CH2Ä
/
CHÃR
/
Entry
R
n
Product
Temperature (8C)
Time (h)
Yield (%)
1
CO2Bu
CO2Bu
CO2Bu
CN
3
2
1
3
2
1
3
3
3
3
3
2a
2b
2c
2d
2e
2f
125
125
125
130
130
130
125
125
125
125
125
24
20
20
30
30
24
24
24
24
24
24
98
95
98
74
85
91
92
93
86
91
89
2
3
4
5
CN
CN
6
7
n-C4H9
n-C8H17
n-C14H29
Ph
2g
2h
2i
8
9
10
11
2j
2k
4-ClÃ/Ph
See Section 4 for details of reaction conditions and product analysis.

304
L. Xu et al. / Journal of Organometallic Chemistry 687 (2003) 301ꢂ312
/
could be effected when a mixture of DMF/water was
used as solvent [23]. In continuing our interest of
catalysis in ionic liquids [22,24], we thought that the
ionic environment generated from an ionic liquid such
as [bmim][BF4] might also promote the regioselective
functionalization of haloarylphosphine oxides. The
arylation of n-butyl vinyl ether by 1a was first examined
in [bmim][BF4] under the previously established reaction
conditions, where the active catalyst was generated in
situ from Pd(OAc)2 and two equivalents of 1,3-bis(di-
phenylphosphino)propane (DPPP). The oxide 1a did
react with the butyl vinyl ether to give preferentially the
a arylated product, although the conversion was only
about 30% at 100 8C after 24 h. The b product was not
detected by NMR. On the basis of this initial study, the
in situ from Pd2(dba)3 and four equivalents of PPh3,
which was chosen as the ligand due to its ready
availability and ease of handling. Table 3 summaries
the results obtained. As can be seen, the aryl bromides
1aꢂc coupled readily with phenylboronic acids and
/
other substituted phenylboronic acids to give the biaryls
in excellent yields regardless of the number of bromides
in 1 and the nature of the substituents at arylboronic
acids. However, when tris(4-bromophenyl)phosphine
was employed as substrate, the coupling reaction
became sluggish, yielding very low conversion, which
is reminiscent of the Heck reaction discussed above and
in line with Trost’s observation [12]. This efficient
coupling process could thus be used to prepare aromatic
phosphines with interesting structures and electronic
bromides 1aꢂ/c were olefinated with n-butyl vinyl ether
properties. Compounds 4aꢂc have previously been
/
at a higher temperature, 125 8C, in [bmim][BF4]. As
shown in Table 2, the acetyl substituted phosphine
made by lithiation and other methods [25].
oxides 3aꢂ
tion with HCl.
/
c were obtained in good yields after acidifica-
2.3. Synthesis of functionalized arylphosphine oxides by
amination
Owing to the excellent studies by the research groups
of Buchwald and Hartwig, the palladium-catalyzed
amination of aryl halides has been under intensive
research in recent years [11]. Among the ligands
employed in the amination, Nolan and co-workers
found that the readily available, nucleophilic N-hetero-
cyclic carbenes, an alternative to electron-rich phos-
phines [26], displayed good performance in palladium-
catalyzed amination of aryl halides [27]. Using Nolan’s
conditions, we carried out the amination of aryl
2.2. Synthesis of functionalized arylphosphine oxides by
Suzuki coupling
The Suzuki coupling is one of the most powerful tools
for the synthesis of biaryls, but has rarely been
employed for the direct preparation of phosphine
ligands (vide ante) [4]. In general, Suzuki reactions can
be more easily performed with aryl bromides and
iodides than with aryl chlorides. Indeed, despite the
presence of electron-withdrawing PÄ
/
O moiety, tris(4-
bromides 1aꢂc in the presence of palladium and the
/
chlorophenyl)phosphine oxide was inactive towards
arylboronic acids under normal Suzuki reaction condi-
tions. Our recent investigation shows that arylboronic
acids can be readily coupled with OPPh2(o-C6H4Br)
under palladium catalysis, providing an easy entry to
functionalized biphenyl-based phosphines [17c]. Bearing
bulky carbene precursor, 1,3-bis(2,6-diisopropylphen-
yl)imidazolium chloride (IPrHCl) [28]. A typical reac-
tion consisted of simply heating a mixture of substrates,
Pd2(dba)3, IPrHCl and KOtBu in dioxane under an
atmosphere of argon. All the reactions went to comple-
tion in 20ꢂ
As shown, oxides 1aꢂ
methylaniline in good yields. Due to the easy availability
and diversity of amines, this process offers another route
to functionalized phosphine ligands, for example, those
/
24 h. The results are summarized in Table 4.
this success in mind, we attempted the coupling of 1aꢂc
/
/c could be easily aminated by N-
with arylboronic acids. The coupling reaction was
carried out with 1, 1.1 equivalent of an arylboronic
acid, two equivalents of a base (relative to Br) in 1,4-
dioxane at 105 8C. The palladium catalyst was generated
Table 2
Heck coupling of OPPh3ꢀn (4-C6H4Ã
/
Br)n with CH2Ä
/
CHÃ
/
OÃBu
/
Entry
n
Product
Time (h)
Yield (%)
1
2
3
3
2
1
3a
3b
3c
30
24
24
52
70
80

L. Xu et al. / Journal of Organometallic Chemistry 687 (2003) 301ꢂ
/
312
305
Table 3
Suzuki coupling of OPPh3ꢀn (4-C6H4Br)n with arylboronic acids
Entry
Ar
n
Product
Temperature (8C)
Time (h)
Yield
1
2
3
4
5
6
7
Ph
Ph
Ph
3
2
1
3
1
1
1
4a
4b
4c
4d
4e
4f
100
100
100
110
110
110
110
20
20
20
24
24
24
24
91
96
96
91
90
89
91
4-CH3Ã
4-CH3Ã
4-CH3OÃ
4-FÃC6H4
/
C6H4
/C6H4
/C6H4
/
4g
that could be made water-soluble upon quaternization
or are immobilizable through hydrogen bonding with
surface hydroxyl groups.
and none are catalytic in nature [29]. Recently, Hayashi
[8a] and Saa [6f] reported the synthesis of 6c in high yield
by palladium catalysed PÃ
/
C coupling reaction of aryl
triflates with diphenylphosphine oxide. Using our palla-
dium-catalyzed carbonylation route, the phosphines can
now be more easily accessed considering that triflates
are in general not commercially available and secondary
phosphines are often pyrophoric. Phosphine oxides such
as 6 can be used not only as precursors to amphiphilic
ligands [17b] but also as monomers to fire resistant
polymers [29].
2.4. Synthesis of functionalized arylphosphine oxides by
alkoxycarbonylation
Palladium-catalyzed alkoxycarbonylation of aryl ha-
lides provides a facile route for the introduction of
carboxylate groups [11a,b]. Due to the activating effect
of phosphoryl, we envisaged that the carbonylation of
1aꢂ/c could be easily conducted. Indeed, the reactions of
the oxides 1aꢂ/c with CO and methanol in the presence
of PdCl2, PPh3 and triethylamine in DMF proceeded
smoothly to give excellent yields of carbonylated
products, although the tris-brominated 1a required a
longer reaction time for complete conversion than 1c
(Table 5).
This reaction offers a most convenient method for the
synthesis of carbonylated phosphine ligands. Tradition-
ally, the synthesis of 6 involves the use of stoichiometric
Grignard/lithium reagents, or a large excess of oxidant,
3. Conclusions
The results presented in this paper demonstrate that
palladium catalysis provides a simple, but powerful, tool
for the preparation of a wide range of arylphosphine
compounds. The substrates can be selected such that the
phosphine products display designer electronic or solu-
bility properties, and are amenable to further functio-
nalization or immobilization on solids. Specifically, we
Table 4
Amination of OPPh3ꢀn (4-C6H4Br)n with N-methylaniline
Entry
n
Product
Time (h)
Yield (%)
1
2
3
3
2
1
5a
5b
5c
24
20
20
51
71
79

306
L. Xu et al. / Journal of Organometallic Chemistry 687 (2003) 301ꢂ
/
312
Table 5
Methoxycarbonylation of OPPh3ꢀn (4-C6H4Br)n
Entry
n
Product
Time (h)
Yield (%)
1
2
3
3
2
1
6a
6b
6c
24
20
12
90
92
92
have demonstrated that the widely-practiced, palladium-
catalyzed Heck reaction, Suzuki coupling, Buchwaldꢂ
4.1. Tris[4-(2-butoxycarbonylvinyl)phenyl]phosphine
oxide (2a)
/
Hartwig amination and alkoxycarbonylation can be
readily adopted to the preparation of olefinated, ary-
lated, aminated and carbonylated phenylphosphines.
These reactions are easy to conduct, with common
ligands being sufficiently effective to give good to
excellent yields.
A mixture of tris(4-bromophenyl)phosphine oxide 1a
(2.060 g, 4.0 mmol), n-butyl acrylate (2.307 g, 18 mmol),
palladacycle (56 mg, 0.06 mmol) and NaOAc (1.312 g,
16 mmol) in DMF (50 ml) was stirred for 24 h at 125 8C.
After cooling to ambient temperature, most of the DMF
was removed under reduced pressure. The residue was
dissolved in CHCl3 (50 ml), washed with water (2ꢄ50
/
ml) and brine (50 ml), dried (MgSO4) and evaporated
under reduced pressure. The residue was purified by
4. Experimental
flash chromatography (EtOAc/CHCl3ꢁ
/
1/4) to give 2a
as white crystals (2.602 g, 98%). H-NMR (300 MHz,
CDCl3, Me4Si): dꢁ 7.2 Hz, 9H), 1.43
0.97 (t, 3J(H, H)ꢁ
(m, 6H), 1.69 (m, 6H), 4.25 (t, J(H, H)ꢁ
1
All reactions were performed under an inert atmo-
1
/
/
sphere and anhydrous conditions. H- and 13C-NMR
3
/
6.6 Hz, 6H),
3
spectra were obtained on a Varian Gemini 300 or a
Bruker Avance 400 spectrometer in CDCl3 with Me4Si
as internal standard. 31P{1H}-NMR spectra were re-
corded on a Bruker WM 250 spectrometer in CDCl3
with 85% H3PO4 as external standard. Elemental
analysis was performed by the Microanalysis Labora-
tory, Department of Chemistry, University of Liver-
pool. Mass spectra were obtained by electron ionization
(EI) recorded on a VG7070E mass spectrometer. Silica
gel (Daiso gel IR-60) was used for column chromato-
graphy. 1,4-Dioxane was distilled over Na/benzophe-
none under nitrogen. DMF and NEt3 were distilled
under nitrogen over CaH2 and stored over activated 4A
molecular sieves. Commercial deuterated chloroform for
NMR spectroscopy and solvents for chromatography
were used without further purification. Olefins, aryl-
boronic acids, N-methylaniline, potassium tert-butox-
ide, PdCl2, Pd(OAc)2, Pd2(dba)3, PPh3 and DPPP were
purchased from Aldrich and Lancaster, and used with-
out further purification. 1-Butyl-3-methylimidazolium
tetrafluoroborate ([bmim][BF4]) [30] and IPrHCl [28]
were prepared according to published procedures; so
were the bromophenylphosphine oxides OPPh3ꢀn(4-
6.52 (d, J(H, H)ꢁ
13C{1H}-NMR (75 MHz, CDCl3): dꢁ
64.7, 121.2, 128.1 (d, 3J(C, P)ꢁ
P)ꢁ
9.8 Hz), 133.7 (d, 1J(C, P)ꢁ
/
16.1 Hz, 3H), 7.61ꢂ
/
7.73 (m, 15H);
/
13.7, 19.2, 30.7,
12.5 Hz), 132.6 (d, 2J(C,
103.7 Hz), 138.4,
27.3 (s); MS
/
/
/
142.9, 166.6; 31P{1H}-NMR (CDCl3): dꢁ
/
(EI), m/z (%): 656 (Mꢃ, 23); Anal. Calc. for C39H45O7P:
C, 71.32; H, 6.91. Found: C, 71.27; H, 6.88%.
4.2. Bis[4-(2-butoxycarbonylvinyl)phenyl]-
phenylphosphine oxide (2b)
The procedure was similar to that for 2a; 2b was
1
obtained as colorless oil in 95% yield. H-NMR (400
MHz, CDCl3, Me4Si): d 0.95 (t, 3J(H, H)ꢁ
7.5 Hz, 6H),
/
3
1.42 (m, 4H), 1.68 (m, 4H), 4.21 (t, J(H, H)ꢁ
/6.7 Hz,
3
4H), 6.56 (d, J(H, H)ꢁ
/
16.1 Hz, 2H), 7.44ꢂ
/
7.76 (m,
15H); 13C-NMR (100 MHz, CDCl3), d 14.0, 19.4, 30.7,
64.9, 121.2, 128.3 (d, 3J(C, P)ꢁ
/
12.5 Hz), 129.0 (d, 3J(C,
1
P)ꢁ
/
12.0 Hz), 132.0 (d, J(C, P)ꢁ104.6 Hz), 132.2 (d,
/
2J(C, P)ꢁ
/
9.9 Hz), 132.6, 132.8 (d, J(C, P)ꢁ10.1 Hz),
103.1 Hz), 138.3, 143.2, 166.7; 31P-
/
2
1
134.2 (d, J(C, P)ꢁ
/
NMR (101 MHz, CDCl3) d 28.3 (s); MS (EI), m/z (%):
530 (Mꢃ, 79), 531 (25), 532 (7), 529 (100); Anal. Calc.
for C32H35O5P: C, 72.44; H, 6.65. Found: C, 72.66; H,
6.55%.
C6H4Br)n (nꢁ
/
3, 1a; 2, 1b; 1, 1c) [19] and the
HerrmannꢂBeller palladacycle catalyst [18].
/

L. Xu et al. / Journal of Organometallic Chemistry 687 (2003) 301ꢂ
/
312
307
3
3
4.3. [4-(2-butoxycarbonylvinyl)phenyl]-
diphenylphosphine oxide (2c)
127.7 (d, J(C, P)ꢁ
/
12.7 Hz), 129.2 (d, J(C, P)ꢁ
/
11.9
10.3 Hz), 133.1 (d, 2J(C,
Hz), 131.7, 132.3 (d, 2J(C, P)ꢁ
/
1
P)ꢁ
/
10.3 Hz), 133.4 (d, J(C, P)ꢁ
/
102.1 Hz), 135.5 (d,
102.4 Hz), 137.3, 149.4; 31P-NMR (101 MHz,
The procedure was similar to that for 2a; 2c was
1
obtained as colorless oil in 98% yield. H-NMR (400
1J(C, P)ꢁ
/
CDCl3): d 28.3 (s); MS (EI), m/z (%): 380 (Mꢃ, 64), 379
(100), 381 (15); Anal. Calc. for C24H17N2OP: C, 75.78;
H, 4.50; N, 7.36. Found: C, 75.63; H, 4.59; N, 7.19%.
MHz, CDCl3, Me4Si): d 0.96 (t, 3J(H, H)ꢁ
7.5 Hz, 3H),
/
3
1.42 (m, 2H), 1.69 (m, 2H), 4.22 (t, J(H, H)ꢁ
/
6.6 Hz,
3
2H), 6.51 (d, J(H, H)ꢁ
4H), 7.53ꢂ7.59 (m, 4H), 7.65ꢂ
(100 MHz, CDCl3): d 13.7, 19.2, 30.8, 64.7, 120.8, 127.8
/
16.1 Hz, 1H), 7.44ꢂ
/
7.49 (m,
/
/
7.72 (m, 7H); 13C-NMR
4.6. [4-(2-cyanovinyl)phenyl]diphenylphosphine oxide
(2f)
3
3
(d, J(C, P)ꢁ
/
12.7 Hz), 128.6 (d, J(C, P)ꢁ12.5 Hz),
/
132.0 (d, 2J(C, P)ꢁ
/
9.5 Hz), 132.1, 132.3 (d, 1J(C, P)ꢁ
/
The procedure was similar to that for 2d; 2f was
1
obtained as white crystals in 91% yield. H-NMR (400
2
104.0 Hz), 132.6 (d, J(C, P)ꢁ
/
10.3 Hz), 134.6 (d, 1J(C,
3
P)ꢁ
/
102.4 Hz), 137.9, 143.1, 166.5; 31P-NMR (101
MHz, CDCl3, Me4Si): d 5.59 (d, J(H, H)ꢁ
/12.1 Hz,
MHz, CDCl3): d 29.5 (s); MS (EI), m/z (%): 404
(Mꢃ, 53), 403 (100), 405 (13); Anal. Calc. for
C25H25O3P: C 74.24; H, 6.23. Found: C, 73.93; H,
6.21%.
0.05H, Z isomer), 5.99 (d, 3J(H, H)ꢁ
/
16.7 Hz, 0.95H, E
12.1 Hz, 0.05H, Z isomer),
16.7 Hz, 0.95H, E isomer), 7.46ꢂ
3
isomer), 7.19 (d, J(H, H)ꢁ
/
3
7.43 (d, J(H, H)ꢁ
7.51 (m, 4H), 7.53ꢂ
13C-NMR (100 MHz, CDCl3): d 99.4, 118.0, 127.6 (d,
3J(C, P)ꢁ11.9 Hz), 129.1 (d, 3J(C, P)ꢁ
11.9 Hz), 132.2
104.8 Hz), 132.4 (d, J(C, P)ꢁ10.3 Hz),
9.5 Hz), 136.2 (d, 1J(C, P)ꢁ
/
/
/
7.60 (m, 4H), 7.64ꢂ7.75 (m, 6H);
/
4.4. Tris[4-(2-cyanovinyl)phenyl]phosphine oxide (2d)
/
/
1
2
(d, J(C, P)ꢁ
/
/
A mixture of 1a (2.060 g, 4.0 mmol), acrylonitrile
(1.273 g, 24 mmol), palladacycle (56 mg, 0.06 mmol),
and NaOAc (1.182 g, 14 mmol) in DMF (50 ml) was
stirred for 30 h at 130 8C. After cooling to ambient
temperature the mixture was poured into water (50 ml).
132.7, 133.2 (d, 2J(C, P)ꢁ
/
/
101.6 Hz), 137.0, 149.6; 31P-NMR (101 MHz, CDCl3): d
29.1 (s); MS (EI), m/z (%): 329 (Mꢃ, 49), 328 (100), 330
(10); Anal. Calc. for C21H16NOP: C, 76.59; H, 4.90; N,
4.25. Found: C, 76.39; H, 4.92; N, 4.25%.
The product was extracted with CHCl3 (3ꢄ
/
30 ml). The
50
ml) and brine (50 ml), dried (MgSO4) and evaporated
combined organic layers were washed with water (2ꢄ
/
4.7. Tris[4-(1-hexenyl)phenyl]phosphine oxide (2g)
under reduced pressure. The residue was purified by
The procedure was similar to that for 2a except nine
equivalents (relative to phosphorus) of 1-hexene was
used. After purification by flash chromatography
(CHCl3), 2g was obtained as colorless oil in 92% yield,
which contained 10% of tris[4-(2-hexenyl)phenyl]phos-
flash chromatography (EtOAc/CHCl3ꢁ1/4) and crys-
/
tallized from EtOAc to give 2d as white crystals (1.276 g,
1
74%). H-NMR (400 MHz, CDCl3, Me4Si): d 5.61 (d,
3J(H, H)ꢁ
H)ꢁ
Hz, 0.3H, Z isomer), 7.43(d, J(H, H)ꢁ
/
12.1 Hz, 0.3H, Z isomer), 5.99 (d, 3J(H,
/
16.7 Hz, 2.7H, E isomer), 7.19 (d, 3J(H, H)ꢁ
/
12.1
16.7 Hz, 2.7H,
phine oxide. 1H-NMR (300 MHz, CDCl3, Me4Si): d
3
3
/
0.92 (t, J(H, H)ꢁ
/
7.2 Hz, 9H), 1.41 (m, 12H), 2.23 (m,
3
3
4
4
7.9 Hz, J(P,
E isomer), 7.57 (dd, J(H, H)ꢁ
/
8.2 Hz, J(P, H)ꢁ
/
2.4
11.7 Hz, 6H); 13C-NMR
6H), 6.38 (m, 6H), 7.40 (dd, J(H, H)ꢁ
/
3
3
3
11.5 Hz, J(H,
Hz, 6H), 7.71 (dd, J(P, H)ꢁ
/
H)ꢁ
/
2.4 Hz, 6H), 7.58 (dd, J(P, H)ꢁ
/
(100 MHz, CDCl3): d 100.1, 117.6, 127.8 (d, 3J(C, P)ꢁ
/
H)ꢁ
/
7.9 Hz, 6H); 13C-NMR (75 MHz, CDCl3): d 13.9,
2
1
10.3 Hz), 134.8 (d, J(C,
3
12.4 Hz), 133.1 (d, J(C, P)ꢁ
/
22.2, 31.3, 32.8, 125.9 (d, J(C, P)ꢁ
130.82 (d, J(C, P)ꢁ
/
12.1 Hz), 129.04,
2
1
P)ꢁ
/
104.1 Hz), 137.6, 149.1; 31P-NMR (101 MHz,
/
105.9 Hz), 132.42 (d, J(C, P)ꢁ
/
CDCl3): d 26.9 (s); MS (EI), m/z (%): 431 (Mꢃ, 75),
430 (100), 432 (20); Anal. Calc. for C27H18N3OP: C,
75.17; H, 4.21; N, 9.74. Found: C, 75.13; H, 4.17; N,
9.70%.
10.4 Hz), 134.16, 141.46; 31P-NMR (101 MHz, CDCl3):
d 28.6 (s); MS (EI), m/z (%): 524 (Mꢃ, 100), 523 (94),
526 (35), 540 (9); Anal. Calc. for C36H45OP: C, 82.40; H,
8.64. Found: C, 82.27; H, 8.73%.
4.5. Bis[4-(2-cyanovinyl)phenyl]phenylphosphine oxide
(2e)
4.8. Tris[4-(1-decenyl)phenyl]phosphine oxide (2h)
The procedure was similar to that for 2a except 4.5
equivalents (relative to phosphorus) of 1-decene was
used. After purification by flash chromatography
(CHCl3), 2h was obtained as colorless oil in 93% yield,
which contained 10% tris[4-(2-decenyl)phenyl]phosphine
The procedure was similar to that for 2d; 2e was
1
obtained as white crystals in 85% yield. H-NMR (400
3
MHz, CDCl3, Me4Si): d 5.60 (d, J(H, H)ꢁ
/
12.0 Hz,
16.6 Hz, 1.9H, E
3
0.1H, Z isomer), 5.99 (d, J(H, H)ꢁ
/
3
isomer), 7.18 (d, J(H, H)ꢁ
7.42 (d, 3J(H, H)ꢁ
16.7 Hz, 1.9H, E isomer), 7.49ꢂ
(m, 13H); 13C-NMR (100 MHz, CDCl3); d 99.7, 117.7,
/
12.2 Hz, 0.1H, Z isomer),
oxide. 1H-NMR (300 MHz, CDCl3): 0.85 (t, 3J(H, H)ꢁ
7.0 Hz, 9H), 1.23 (br, 36H), 2.12ꢂ2.38 (m, 6H), 6.39 (m,
6H), 7.36ꢂ
7.61 (m, 12H); 31P-NMR (101 MHz, CDCl3):
/
/
/
7.90
/
/

308
L. Xu et al. / Journal of Organometallic Chemistry 687 (2003) 301ꢂ312
/
d 30.8 (s); MS (EI), m/z (%): 693(Mꢃ, 49), 635 (10),
555(100); Anal. Calc. for C48H69OP: C, 83.19; H, 10.03.
Found: C, 82.86; H, 10.00%.
added and, after 0.5 h of stirring, the product was
extracted with CHCl3 (3ꢄ15 ml). The combined
organic layers were washed with water (2ꢄ30 ml) and
/
/
brine (30 ml), dried (MgSO4) and evaporated under
reduced pressure. The residue was purified by flash
4.9. Tris[4-(1-hexadecenyl)phenyl]phosphine oxide (2i)
chromatography (EtOAc/hexaneꢁ40/1) to give 3a as
/
The procedure was similar to that for 2a except four
equivalents (relative to phosphorus) of 1-hexadecene
was used; 2i was obtained as colorless oil in 86% yield,
which contained about 10% of tris[4-(2-hexadece-
colorless oil (210 mg, 52%). 1H-NMR (400 MHz,
3
CDCl3, Me4Si): d 2.64 (s, 9H), 7.79 (dd, J(H, H)ꢁ
/
8.3 Hz, 3J(P, H)ꢁ
/
11.1 Hz, 6H), 8.05 (d, 6H); 13C-NMR
3
(100 MHz, CDCl3): d 26.8, 128.3 (d, J(C, P)ꢁ
/11.9
2
1
nyl)phenyl]phosphine oxide. 1H-NMR (300 MHz,
Hz), 132.4 (d, J(C, P)ꢁ
/
10.3 Hz), 136.4 (d, J(C, P)ꢁ
/
3
CDCl3, Me4Si): 0.88 (t, J(H, H)ꢁ
/
7.0 Hz, 9H), 1.24
7.60
(m, 12H); 31P-NMR (101 MHz, CDCl3): d 30.8 (s); MS
(FAB), m/z (%): 946 (Mꢃꢃ
1, 62), 962 (100), 978 (83),
101.6 Hz), 140.1, 197.2; 31P-NMR (101 MHz, CDCl3): d
27.8 (s); MS (EI), m/z (%): 404 (Mꢃ, 59), 403 (100), 405
(12); Anal. Calc. for C24H21O4P: C, 71.28; H, 5.23.
Found: C, 71.52; H, 5.13%.
(br, 72H), 2.05ꢂ
/
2.35 (m, 6H), 6.39 (m, 6H), 7.42ꢂ
/
/
994 (42); Anal. Calc. for C66H105OP: C, 83.84; H, 11.19.
Found: C, 84.07; H, 11.27%.
4.13. Bis(4-acetylphenyl)phenylphosphine oxide (3b)
[31]
4.10. Tris[4-(trans-styryl)phenyl)]phosphine oxide (2j)
The procedure was similar to that for 2a; 2j was
The procedure was similar to that for 3a except ten
equivalents (relative to phosphorus) of n-butyl vinyl
ether was used; 3b was obtained as colorless oil in 70%
1
obtained as white crystals in 91% yield. H-NMR (400
3
1
MHz, CDCl3, Me4Si): d 7.12 (d, J(H, H)ꢁ
/
16.4 Hz,
7.30 (m,
7.4 Hz, J(P, H)ꢁ7.4 Hz,
7.8 Hz, 6H), 7.60 (d, J(H,
7.71 (m, 6H); 31P-NMR (101
yield. H-NMR (400 MHz, CDCl3, Me4Si): d 2.63 (s,
3
3
3H), 7.21 (d, J(H, H)ꢁ
/
16.4 Hz, 3H), 7.22ꢂ
/
6H), 7.48ꢂ
3J(P, H)ꢁ
4H); 13C-NMR (100 MHz, CDCl3): d 27.1, 128.5 (d,
3J(C, P)ꢁ11.9 Hz), 129.2 (d, 3J(C, P)ꢁ
11.9 Hz), 131.6
104.8 Hz), 132.4 (d, J(C, P)ꢁ10.3 Hz),
/
7.68 (m, 5H), 7.79 (dd, J(H, H)ꢁ
/
8.4 Hz,
2.4 Hz,
3
3
4
3H), 7.37 (dd, J(H, H)ꢁ
/
/
/
11.6 Hz, 4H), 8.03 (dd, J(P, H)ꢁ
/
3
3
6H), 7.52 (d, J(H, H)ꢁ
/
H)ꢁ
/
7.5 Hz, 6H), 7.67ꢂ
/
/
/
MHz, CDCl3): d 29.6 (s); MS (EI), m/z (%): 584 (Mꢃ,
81), 583 (51), 585 (31); Anal. Calc. for C42H33OP: C,
86.28; H, 5.69. Found: C, 86.17; H, 5.68%.
(d, J(C, P)ꢁ
/
/
1
2
132.8 (d, 2J(C, P)ꢁ
/
10.3 Hz), 133.0, 137.4 (d, 1J(C, P)ꢁ
/
100.1 Hz), 140.2, 197.7; 31P-NMR (101 MHz, CDCl3): d
28.6 (s); MS (EI), m/z (%): 362 (Mꢃ, 47), 361 (100), 362
(7); Anal. Calc. for C22H19O3P: C, 72.92; H, 5.28.
Found: C, 73.02; H, 5.25%.
4.11. Tris[4-(trans-4-chlorostyryl)phenyl]phosphine
oxide (2k)
The procedure was similar to that for 2a; 2k was
1
obtained as white crystals in 89% yield. H-NMR (400
4.14. (4-Acetylphenyl)diphenylphosphine oxide (3c)
[31]
3
MHz, CDCl3, Me4Si): d 7.07 (d, J(H, H)ꢁ
/
16.4 Hz,
3
16.4 Hz, 3H), 7.33 (d, J(H,
3
3H), 7.14 (d, J(H, H)ꢁ
/
The procedure was similar to that for 3a except five
equivalents (relative to phosphorus) of n-butyl vinyl
ether was used; 3c was obtained as colorless oil in 80%
3
H)ꢁ
/
8.4 Hz, 6H), 7.44 (d, J(H, H)ꢁ
/
8.6 Hz, 6H), 7.58
3
3
(d, J(H, H)ꢁ
3J(P, H)ꢁ11.4 Hz, 6H); 13C-NMR (100 MHz, CDCl3):
d 126.9 (d, 3J(C, P)ꢁ
12.7 Hz), 128.3, 128.4, 129.4,
/
8.6 Hz, 6H), 7.68 (dd, J(H, H)ꢁ
/8.3,
1
/
yield. H-NMR (400 MHz, CDCl3, Me4Si): d 2.62 (s,
3
/
3H), 7.46ꢂ
/
7.69 (m, 10H), 7.80 (dd, J(H, H)ꢁ
/
8.6 Hz,
1
2
4
130.4, 132.0 (d, J(C, P)ꢁ
/
105.6 Hz), 132.9 (d, J(C,
3J(P, H)ꢁ
/
11.3 Hz, 2H), 8.02 (dd, J(P, H)ꢁ
/
2.0 Hz,
2H); 13C-NMR (100 MHz, CDCl3): d 27.1, 128.4 (d,
P)ꢁ
/
10.3 Hz), 134.3, 135.6, 141.0; 31P-NMR (101 MHz,
CDCl3): d 29.4; MS (EI), m/z (%): 688 (Mꢃ, 23), 689
(13), 690 (9), 687 (23), 686 (23), 685 (17); Anal. Calc. for
C42H30Cl3OP: C, 73.32; H, 4.39. Found: C, 72.98; H,
4.61%.
3J(C, P)ꢁ
/
12.7 Hz), 129.0 (d, 3J(C, P)ꢁ
12.7 Hz), 132.4
/
2
2
(d, J(C, P)ꢁ
/
9.5 Hz), 132.6, 132.8 (d, J(C, P)ꢁ10.3
/
Hz), 139.9, 197.8; 31P-NMR (101 MHz, CDCl3): d 29.4
(s); MS (EI), m/z (%): 320 (Mꢃ, 41), 319 (100); Anal.
Calc. for C20H17O2P: C, 74.99; H, 5.35. Found: C,
75.12; H, 5.28%.
4.12. Tris(4-acetylphenyl)phosphine oxide (3a) [31]
A mixture of 1a (515 mg, 1.0 mmol), n-butyl vinyl
ether (1.502 g, 15 mmol), Pd(OAc)2 (17 mg, 0.075
mmol), DPPP (62 mg, 0.15 mmol), triethylamine (456
mg, 4.5 mmol) and [bmim][BF4] (5 ml) was stirred for 24
h at 125 8C. At room temperature HCl (5%, 15 ml) was
4.15. Tris(4-biphenylyl)phosphine oxide (4a) [25a]
A mixture of 1a (2.060 g, 4.0 mmol), phenylboronic
acid (1.609 g, 13 mmol), Pd2(dba)3 (55 mg, 0.06 mmol),
PPh3 (126 mg, 0.48 mmol) and K3PO4 (5.095 g, 24

L. Xu et al. / Journal of Organometallic Chemistry 687 (2003) 301ꢂ
/
312
309
mmol) in 1,4-dioxane (50 ml) was stirred overnight at
100 8C. After cooling to room temperature, the mixture
4.19. [4-(4-Tolyl)phenyl]diphenylphosphine oxide (4e)
The procedure was similar to that for 4a; 4e was
was diluted with water and extracted with CHCl3 (3ꢄ
/
1
obtained as white crystal in 90% yield. H-NMR (400
20 ml). The combined organic extracts were washed with
brine, dried over MgSO4 and evaporated in vacuo. The
product was purified by flash chromatography (CHCl3)
and crystallized in EtOAc as white crystals (1.84 g,
3
MHz, CDCl3, Me4Si): d 2.40 (s, 3H), 7.27 (d, J(H,
H)ꢁ
/
8.4 Hz, 2H), 7.44ꢂ
/
7.58 (m, 8H), 7.64ꢂ7.76 (m,
/
8H); 13C-NMR (100 MHz, CDCl3): d 21.2, 127.0 (d,
91%). 1H-NMR (400 MHz, CDCl3, Me4Si): d 7.34ꢂ
(m, 3H), 7.44ꢂ 7.4 Hz,
7.48 (m, 6H), 7.62 (d, 3J(H, H)ꢁ
6H), 7.72 (d, 3J(H, H)ꢁ
7.4 Hz, 6H), 7.80ꢂ7.85 (m,
6H); 13C-NMR (75 MHz, CDCl3): d 127.3 (d, J(C,
P)ꢁ 105.4
9.3 Hz), 128.2, 129.0, 131.4 (d, 1J(C, P)ꢁ
Hz), 132.7(d, 3J(C, P)ꢁ9.8 Hz), 140.0, 144.9; 31P-NMR
/
7.41
3J(C, P)ꢁ
129.7, 130.8 (d, J(C, P)ꢁ
2J(C, P)ꢁ
/
12.7 Hz), 127.1, 128.5 (d, 3J(C, P)ꢁ
/
12.9 Hz),
103.1 Hz), 131.9, 132.2 (d,
1
/
/
/
2
/
/
/
9.5 Hz), 132.3, 132.6 (d, J(C, P)ꢁ
/
10.0 Hz),
2
1
132.8 (d, J(C, P)ꢁ
104.0 Hz), 138.2, 144.7; 31P-NMR
/
/
/
(101 MHz, CDCl3): d 30.1 (s); MS (EI), m/z (%): 368
(Mꢃ, 64), 367 (100), 369 (14); Anal. Calc. for
C25H21OP: C, 81.50; H, 5.75. Found: C, 81.33; H,
5.73%.
/
(101 MHz, CDCl3): d 29.8 (s); MS (EI), m/z (%): 506
(83, Mꢃ), 507 (25), 505 (97), 429 (14), 351 (17), 337 (39),
306 (21); Anal. Calc. for C36H27OP: C, 85.36; H, 5.37.
Found: C, 85.07; H, 5.41%.
4.20. [4-(4-Methoxyphenyl)phenyl]diphenylphosphine
oxide (4f)
4.16. Bis(4-biphenylyl)phenylphosphine oxide (4b)
The procedure was similar to that for 4a; 4b was
1
obtained as white crystal in 96% yield. H-NMR (400
The procedure was similar to that for 4a; 4f was
1
obtained as white crystal in 89% yield. H-NMR (400
MHz, CDCl3, Me4Si): d 3.85 (s, 3H), 6.98 (m, 2H),
MHz, CDCl3, Me4Si): d 7.36ꢂ
(m, 6H), 7.55ꢂ7.62 (m, 5H), 7.70 (dd, J(H, H)ꢁ
Hz, J(H, H)ꢁ2.7 Hz, 4H), 7.73ꢂ
7.81 (m, 6H); 31P-
NMR (101 MHz, CDCl3): d 29.8 (s); MS (EI), m/z (%):
430 (Mꢃ, 64), 429 (100), 431 (18); Anal. Calc. for
C30H23OP: C, 83.70; H, 5.39. Found: C, 84.00; H,
5.44%.
/
7.41(m, 2H), 7.44ꢂ
/
7.52
7.34ꢂ
/
7.48 (m, 4H), 7.52ꢂ
/
7.57 (m, 4H), 7.64ꢂ7.74 (m,
/
3
/
/
8.4
8H); 13C-NMR (100 MHz, CDCl3): d 55.4, 114.5, 127.1
4
3
3
/
/
(d, J(C, P)ꢁ
/
11.9 Hz), 128.4, 128.5 (d, J(C, P)ꢁ
/11.9
Hz), 130.4 (d, 1J(C, P)ꢁ
/
104.8 Hz), 131.9, 132.1(d,
2
2J(C, P)ꢁ
/
9.5 Hz), 132.6 (d, J(C, P)ꢁ
/
10.3 Hz), 132.9
1
(d, J(C, P)ꢁ
/
102.4 Hz), 144.3, 159.9; 31P-NMR (101
MHz, CDCl3): d 30.1; MS (EI), m/z (%): 384 (Mꢃ, 71),
383 (100), 385 (15), 307 (11); Anal. Calc. for C25H21O2P:
C, 78.11; H, 5.51. Found: C, 78.20; H, 5.51%.
4.17. (4-Biphenylyl)diphenylphosphine oxide (4c) [25b]
The procedure was similar to that for 4a; 4c was
1
obtained as white crystal in 96% yield. H-NMR (400
4.21. [4-(4-Fluorophenyl)phenyl]diphenylphosphine
oxide (4g)
MHz, CDCl3, Me4Si): d 7.36ꢂ
/
7.40 (m, 1H), 7.43ꢂ
/
7.49
7.76 (m, 8H); 31P-
(m, 6H), 7.53ꢂ7.61 (m, 4H), 7.65ꢂ
/
/
The procedure was similar to that for 4a; 4g was
1
obtained as white crystals in 91% yield. H-NMR (400
NMR (101 MHz, CDCl3): d 30.1 (s); MS (EI), m/z (%):
354 (Mꢃ, 55), 353 (100), 355 (11); Anal. Calc. for
C24H19OP: C, 81.34; H, 5.40. Found: C, 81.39; H,
5.39%.
3
MHz, CDCl3, Me4Si): d 7.15 (dd, J(H, H)ꢁ
/
8.7 Hz,
7.59
2.0 Hz,
7.76 (m, 6H); 31P-NMR (101 MHz, CDCl3):
3J(H, F)ꢁ
(m, 4H), 7.63 (dd, 3J(H, H)ꢁ
/
8.7 Hz, 2H), 7.46ꢂ
/
7.50 (m, 4H), 7.54ꢂ
/
/
8.1 Hz, 4J(P, H)ꢁ
/
2H), 7.69ꢂ
/
4.18. Tris[4-(4-tolyl)phenyl]phosphine oxide (4d)
The procedure was similar to that for 4a; 4d was
d 29.9 (s); MS (EI), m/z (%): 372 (Mꢃ, 56), 371 (100),
373 (12); Anal. Calc. for C24H18OFP: C, 77.41; H, 4.87.
Found: C, 77.70; H, 4.83%.
1
obtained as white crystal in 91% yield. H-NMR (400
3
MHz, CDCl3, Me4Si): d 2.40 (s, 9H), 7.26 (d, J(H,
4.22. Tris[4-(N-methyl-N-phenylamino)phenyl]-
phosphine oxide (5a)
H)ꢁ
/
7.8 Hz, 6H), 7.51 (d, 6H), 7.69 (dd, 3J(H, H)ꢁ
/
8.3
4
3
Hz, J(P, H)ꢁ
/
2.5 Hz, 6H), 7.79 (dd, J(P, H)ꢁ
/
11.6
Hz, 6H); 13C-NMR (100 MHz, CDCl3): d 21.5, 127.4 (d,
A mixture of 1a (2.060 g, 4.0 mmol), N-methylaniline
(1.543 g, 14 mmol), Pd2(dba)3 (110 mg, 0.12 mmol),
IPrHCl (103 mg, 0.24 mmol) and KOtBu (2.02 g, 18
mmol) in 1,4-dioxane (50 ml) was stirred for 24 h at
100 8C. After cooling to room temperature, the mixture
3J(C, P)ꢁ
/
11.9 Hz), 127.5, 130.1, 131.4 (d, J(C, P)ꢁ
/
1
2
105.6 Hz), 133.0 (d, J(C, P)ꢁ10.3 Hz), 137.5, 138.5,
/
145.1; 31P-NMR (101 MHz, CDCl3): d 29.9 (s); MS
(EI), m/z (%): 548 (Mꢃ, 93), 547 (100), 549 (30), 550 (6);
HRMS Calc. for C39H33OP [Mꢃ]: 548.22693; Found:
548.22885; Anal. Calc. for C39H33OP: C, 85.38; H, 6.06.
Found: C, 85.61; H, 5.98%.
was diluted with water and extracted with CHCl3 (3ꢄ
/
20 ml). The combined organic extracts were washed with
brine, dried over MgSO4 and evaporated in vacuo. The

310
L. Xu et al. / Journal of Organometallic Chemistry 687 (2003) 301ꢂ312
/
product was purified by flash chromatography (EtOAc/
was diluted with water and extracted with CHCl3 (3ꢄ
/
1
1/2) to give 5a as yellow oil (1.21g, 51%). H-
NMR (400 MHz, CDCl3, Me4Si): d 3.32 (s, 9H), 6.81
CHCl3ꢁ
/
20 ml). The combined organic extracts were washed with
brine, dried over MgSO4 and evaporated in vacuo. The
product was purified by flash chromatography (EtOAc/
3
4
(dd, J(H, H)ꢁ
7.17 (m, 9H), 7.32ꢂ
11.3 Hz, 6H); 13C-NMR (100 MHz, CDCl3): d 40.1,
/
8.9 Hz, J(P, H)ꢁ
/
2.2 Hz, 6H), 7.11ꢂ
/
3
/
7.37 (m, 6H), 7.46 (dd, J(P, H)ꢁ
/
hexaneꢁ
/
8/1); 6a was obtained as white crystalline solid
1
(431 mg, 95%). H-NMR (400 MHz, CDCl3, Me4Si): d
3
1
3
3
114.8 (d, J(C, P)ꢁ
/
12.5 Hz), 122.0 (d, J(C, P)ꢁ
/
112.0
3.95 (s, 9H), 7.76 (dd, J(P, H)ꢁ
/
11.7 Hz, J(H, H)ꢁ
/
2
Hz), 124.7, 125.2, 129.7, 133.4 (d, J(C, P)ꢁ
/11.0 Hz),
8.4 Hz, 6H), 8.14 (dd, 4J(P, H)ꢁ
/
2.4 Hz, 6H); 13C-NMR
147.8, 151.3; 31P-NMR (101 MHz, CDCl3) d 30.6; MS
(EI), m/z (%): 593 (Mꢃ, 100), 594 (36), 595 (7), 592 (80),
411 (14), 409 (19), 395 (30); Anal. Calc. for
C39H36N3OP: C, 78.90; H, 6.11; N, 7.08. Found: C,
78.55; H, 6.17; N, 7.09%.
(100 MHz, CDCl3): d 52.9, 130.1 (d, J(C, P)ꢁ
/11.9
3
Hz), 132.4 (d, 2J(C, P)ꢁ
/
10.3 Hz), 134.2, 136.6 (d, 1J(C,
100.8 Hz), 166.4; 31P-NMR (101 MHz, CDCl3): d
P)ꢁ
/
28.1 (s); MS (EI), m/z (%): 452 (Mꢃ, 65), 451 (100).
Anal. Calc. for C24H21O7P: C, 63.72; H, 4.68. Found: C,
63.65; H, 4.74%.
4.23. Bis[4-(N-methyl-N-phenylamino)phenyl]-
phenylphosphine oxide (5b)
4.26. Bis(4-carbomethoxyphenyl)phenylphosphine oxide
(6b) [17b,29a,c]
The procedure was similar to that for 5a; 5b was
1
obtained as colorless oil in 71% yield. H-NMR (400
The procedure was similar to that for 6a; 6b was
obtained as white crystalline solid in 92% yield. 1H-
3
MHz, CDCl3, Me4Si): d 3.32 (s, 6H), 6.81 (dd, J(H,
4
H)ꢁ
/
8.8 Hz, J(P, H)ꢁ
/
2.1 Hz, 4H), 7.11ꢂ
/
7.68 (m, 19
NMR (400 MHz, CDCl3, Me4Si): d 3.94 (s, 6H), 7.47ꢂ
/
H); 13C-NMR (100 MHz, CDCl3): d 40.1, 125.0, 125.5,
128.2 (d, 3J(C, P)ꢁ
11.9 Hz), 129.7, 131.1, 132.1 (d,
2J(C, P)ꢁ
9.5 Hz), 133.3 (d, J(C, P)ꢁ
103.2 Hz), 147.6, 151.5; 31P-NMR (101
7.68 (m, 5H), 7.76 (dd, J(P, H)ꢁ
/
11.9 Hz, J(H, H)ꢁ
/
3
3
/
8.4 Hz, 4H), 8.12 (dd, 4J(P, H)ꢁ
/
2.5 Hz, 4H); 13C-NMR
2
3
/
/11.1 Hz), 134.2
(100 MHz, CDCl3): d 52.8, 129.2 (d, J(C, P)ꢁ
/12.7
1
(d, J(C, P)ꢁ
/
Hz), 129.9 (d, 3J(C, P)ꢁ
P)ꢁ9.5 Hz), 132.3, 132.5 (d, J(C, P)ꢁ
(d, 1J(C, P)ꢁ
/
12.7 Hz), 131.2, 132.2 (d, 2J(C,
MHz, CDCl3): d 30.8 (s); MS (EI), m/z (%): 488 (Mꢃ,
62), 489 (19), 487 (57), 411 (8); Anal. Calc. for
C32H29N2OP: C, 78.67; H, 5.98; N 5.73. Found: C,
78.41; H, 6.21; N, 5.89%.
/
/
10.3 Hz), 133.4
100.8 Hz),
2
/
104.0 Hz), 137.4 (d, 1J(C, P)ꢁ
/
166.5; 31P-NMR (101 MHz, CDCl3) d 28.2; MS (EI), m/
z (%): 394 (Mꢃ, 52), 393 (100), 395 (11), 396 (2); Anal.
Calc. for C22H19O5P: C, 67.00; H, 4.86. Found: C,
66.92; H, 4.86%.
4.24. [4-(N-Methyl-N-phenylamino)phenyl]-
diphenylphosphine oxide (5c)
4.27. (4-Carbomethoxyphenyl)diphenylphosphine oxide
(6c) [6f,8a,17b,29e]
The procedure was similar to that for 5a; 5c was
1
obtained as colorless oil in 79% yield. H-NMR (400
3
MHz, CDCl3): d 3.33 (s, 3H), 6.84 (dd, J(H, H)ꢁ
/
8.8
7.68 (m, 17H); 13C-
The procedure was similar to that for 6a; 6c was
obtained as white crystalline solid in 92% yield. 1H-
NMR (400 MHz, CDCl3, Me4Si): d 3.93 (s, 3H), 7.46ꢂ
4
Hz, J(P, H)ꢁ
/
2.1 Hz, 2H), 7.19ꢂ
/
3
NMR (100 MHz, CDCl3): d 40.4, 114.7 (d, J(C, P)ꢁ
/
/
3
3
13.6 Hz), 125.7, 126.2, 128.7 (d, J(C, P)ꢁ
/
11.9 Hz),
9.5 Hz), 132.8 (d, 1J(C,
7.60 (m, 6H), 7.64ꢂ
/
7.69 (m, 4H), 7.77 (dd, J(H, H)ꢁ
/
3
4
130.2, 131.9, 132.5 (d, 2J(C, P)ꢁ
/
8.4 Hz, J(P, H)ꢁ
2.4 Hz, 2H); 13C-NMR (100 MHz, CDCl3): d 52.5,
128.5, 128.7 (d, 3J(C, P)ꢁ12.7 Hz), 129.5 (d, 3J(C, P)ꢁ
11.9 Hz), 131.8 (d, 1J(C, P)ꢁ104.0 Hz), 132.1 (d, 2J(C,
10.3 Hz), 132.3 (d, J(C, P)ꢁ9.5 Hz), 133.3, 137.5
100.0 Hz), 166.2; 31P-NMR (101 MHz,
CDCl3) d 28.9; MS (EI), m/z (%): 336 (Mꢃ, 82), 335
(100); HRMS (EI, m/z) Calc. for C20H18O3P (Mꢃꢃ
1):
/
11.4 Hz, 2H), 8.12 (dd, J(H, H)ꢁ
/
2
P)ꢁ
/
109.0 Hz), 133.7 (d, J(C, P)ꢁ
/
11.1 Hz), 133.9 (d,
1J(C, P)ꢁ
/
103.1 Hz), 147.9, 152.1; 31P-NMR (101 MHz,
/
/
CDCl3); d 30.4 (s); MS (EI), m/z (%): 383 (Mꢃ, 71), 384
(19), 382 (100), 306 (10); Anal. Calc. for C25H22NOP: C,
78.31; H, 5.78; N, 3.65. Found: C, 78.14; H, 5.91; N,
3.83%.
/
2
P)ꢁ
/
/
1
(d, J(C, P)ꢁ
/
/
4.25. Tris(4-carbomethoxyphenyl)phosphine oxide (6a)
[17b,25a,29b,d]
337.09933. Found: 337.09965; Anal. Calc. for
C20H17O3P: C, 71.40; H, 5.13. Found: C, 71.24; H,
5.18%.
A mixture of 1a (515 mg, 1.0 mmol), PdCl2 (13 mg,
0.075 mmol), PPh3 (40 mg, 0.15 mmol), triethylamine
(456 mg, 4.5 mmol), methanol (10 ml) and DMF (10 ml)
was stirred overnight at 125 8C in an autoclave under 75
bar CO. After cooling to room temperature the CO was
carefully released in a fume cupboard, and the mixture
Acknowledgements
We thank the Liverpool University Graduates Asso-
ciation (Hong Kong) (LX), EPSRC (CB) and Johnson

L. Xu et al. / Journal of Organometallic Chemistry 687 (2003) 301ꢂ
/
312
311
(b) S. Vskocyl, M. Smrcina, V. Hanus, M. Polasek, P. Kocovsky,
J. Org. Chem. 63 (1998) 7738;
Matthey Synetix (JX) for financial support. Johnson
Matthey is gratefully acknowledged for the loan of
palladium.
(c) Y. Uozumi, A. Tanahashi, S.Y. Lee, T. Hayashi, J. Org.
Chem. 58 (1993) 1945;
(d) L. Kurz, G. Lee, D. Morgans, M.J. Waldyke, T. Ward,
Tetrahedron Lett. 31 (1990) 6321.
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