New approaches to fluorinated ligands and their application in catalysis

Article abstract of DOI:10.1016/S0040-4020(02)00213-2

Simple and generic approaches to fluorous soluble ligands have been developed and applied to the synthesis of various fluorinated arylphosphines including polymeric ones. The utility of some of these ligands has been demonstrated in catalysis in supercritical CO₂ (scCO₂) and fluorous solvents.

Full text of DOI:10.1016/S0040-4020(02)00213-2

TETRAHEDRON
Pergamon
Tetrahedron 58 02002) 3889±3899
New approaches to ¯uorinated ligands and their application
in catalysis
Weiping Chen, Lijin Xu, Yulai Hu, Anna M. Banet Osuna and Jianliang Xiaop
Department of Chemistry, Leverhulme Centre for Innovative Catalysis, University of Liverpool, Liverpool L69 7ZD, UK
Received 31 October 2001; revised 18 December 2001; accepted 16 January 2002
AbstractÐSimple and generic approaches to ¯uorous soluble ligands have been developed and applied to the synthesis of various
¯uorinated arylphosphines including polymeric ones. The utility of some of these ligands has been demonstrated in catalysis in supercritical
CO2 0scCO2) and ¯uorous solvents. q 2002 Elsevier Science Ltd. All rights reserved.
1. Introduction
methods, for instance, the per¯uoroalkyl reagents, often the
most expensive of all reagents involved, are introduced in
the ®rst step of synthesis, thus resulting in relatively inef-
®cient utilisation of these reagents. In addition, moisture-
sensitive and pyrophoric reagents and low temperature are
often employed, and some intermediates have proven dif®-
cult to purify.4 To some degree, the dif®culty in the syn-
thesis of ¯uorous phosphines has impeded the exploration of
catalysis in scCO2 and ¯uorous solvents. Therefore, the
design of ef®cient synthetic routes for the ¯uoroalkylation
of ligands including in particular phosphines is of signi®cant
importance to the further development of catalytic processes
in emerging solvents. Simple and high-yield methods
to arylphosphines bearing per¯uorinated ponytails have
recently been developed in our lab, the details of which
are herein described.5 A brief description of their appli-
cation in catalysis in ¯uorous phases and scCO2 is also
given.
One of the current frontiers in homogeneous catalysis
concerns the use as reaction media of non-traditional
solvents such as water, ionic liquids, scCO2 and per¯uoro-
carbons.1,2 For catalysis in some of these solvents, modi®-
cations to ligands are necessary in order to make their metal
complexes soluble. A well established strategy for catalysis
by organometallic complexes in scCO2 and ¯uorous
solvents is to attach long per¯uoroalkyl chains to con-
ventional ligand scaffolds.1,3 Arylphosphines are probably
the most widely used ligands in homogeneous catalysis.2
Consequently, several approaches to per¯uoroalkylated
arylphosphines have been reported. Hope and co-workers
synthesised such phosphines by the Cu-mediated coupling
of iodobromobenzenes with per¯uoroalkyl iodides followed
by lithiation with n-BuLi at 2788C and reaction with
PPh32nCln 0Scheme 1).3h,p Knochel prepared these arylphos-
phines via a similar route; but the per¯uoroalkyl substituted
bromobenzene was obtained by the Sandmeyer reaction.3n
Fluorous arylphosphines, which contain an ethylene spacer
between the aromatic ring and the per¯uoroalkyl group,
were ®rst synthesised by Leitner and co-worker via the
copper-catalysed coupling of a mono Grignard reagent
derived from a dibromobenzene with 1H,1H,2H,2H-per-
¯uoroalkyl iodides followed by the familiar reactions.3o
Improved methods for making related ¯uoroalkylated
aromatic bromides have recently been reported by Gladysz3a
and Curran.3b van Koten has developed a route to ¯uorous
arylphosphines, where the ¯uorous moiety is introduced by
the reaction of dibromobenzene with a ¯uorinated silane.3c,k
While these methods have played an important role in
developing ¯uorinated ligands and catalysis in scCO2 and
¯uorous solvents, none is without disadvantages. In all the
2. Results and discussion
Metal catalysed and mediated C±C coupling reactions have
been widely used in organic synthesis.6 We have succeeded
in applying the chemistry to the synthesis of phosphine and
related ligands, soluble not only in scCO2 and ¯uorous
solvents but in water and ionic liquids as well. Our strategy
is based on the coupling of haloarylphosphine oxides, e.g.
OPPh32n0C6H4Br)n 0nˆ1±3), with alkyl halides, ole®ns,
organoboranes, amines and alcoholic substrates 0Scheme
2). In the particular case of ¯uorous arylphosphines, C±C
coupling of the haloarylphosphine oxides with ¯uorinated
alkyl halides and ole®ns readily furnishes the desired
ligands.
2.1. Synthesis of per¯uoroalkylated arylphosphines by
copper-mediated coupling
Keywords: ¯uorinated ligands; ¯uorinated phosphines; ¯uorinated poly-
mers; C±C coupling; ¯uorous catalysis; supercritical CO2.
Corresponding author. Tel.: 144-151-794-2937; fax: 144-151-794-
3589; e-mail: j.xiao@liv.ac.uk
p
Copper-mediated cross coupling of per¯uoroalkyl iodides
0040±4020/02/$ - see front matter q 2002 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020002)00213-2

3890
W.Chen et al./ Tetrahedron 58 %2002) 3889±3899
Scheme 1. Literature approaches to ¯uorinated arylphosphines.
with iodoaromatic compounds to give per¯uoroalkyl-substi-
tuted aromatics was ®rst reported by McLoughlin and
Thrower.7 The reaction was later extended to include
bromoaromatics and shown to tolerate functional groups
such as OH, CO2R, and NH2.8 Prompted by these early
®ndings, we attempted the coupling of the haloaryl-
phosphine oxides 1 with per¯uoroalkyl iodides 2 0Scheme
3). Since these phosphine oxides are easily available starting
from 1,4-dibromobenzene and phosphorus chlorides and
require no special precautions to handle,9 such a reaction
was anticipated to offer a much simpli®ed route to per-
greater than 90% isolated yields. Table 1summarises the
results. The obtained yields are remarkable, as most
previously reported coupling reactions of aryl iodides and
bromides have yields lower than 70%.7,8 The key to the
success of the current method is the use of oxidised phos-
phines. When bromoarylphosphines were employed instead
of the oxides, complex mixtures were obtained under
otherwise identical reaction conditions. The presence of a
catalytic amount of 2,20-bipyridine 0bipy) in the reaction
lowers the reaction temperature without affecting the
conversion and yield. Bipy may play a role in facilitating
metallation of copper by 2.7 The phosphine oxide 1 may
play a similar role, thus promoting higher yields at milder
conditions. As with the coupling reactions of other halo-
aromatics, DMSO is the solvent of choice.7,8 In DMF, the
¯uoroalkylated phosphines.5a The coupling of OPPhn23
-
04-C6H4Br)n 0nˆ1±3) 1 with IC6F13 2a proceeded smoothly
in the presence of copper powder to give the per¯uorohexyl-
substituted phosphine oxides OPPhn2304-C6H4C6F13)n 3 in
Scheme 2. Metal catalysed or mediated functionalisation of arylphosphies 0nˆ1±3).

W.Chen et al./ Tetrahedron 58 %2002) 3889±3899
3891
Scheme 3. Synthesis of per¯uoroalkylated arylphosphines by Cu-mediated cross-coupling.
reaction was sluggish and less clean. The chloride analogues
OPPhn2304-C6H4Cl)n failed to react. Longer reaction time
was required on going from 1a to 1c due to increasing
substitution by the per¯uorohexyl moiety and accompanied
decrease in solubility of 3 in the solvent. Solubility appears
also to be responsible for the slightly lower yield obtained
with 3ca. Thus, when the reaction was carried out in a
per¯uoro-1,3-dimethylcyclohexane and DMSO 010:1, v/v)
mixture, the yield of 3ca increased to 95%. Solubility was
even more a problem with the longer IC8F17 2b. Thus, when
the reaction of 1c with 2b was performed in DMSO, a yield
of only 45% was obtained for 3cb. Remarkably, when
performed in the per¯uoro-1,3-dimethylcyclohexane and
DMSO mixture, the reaction proceeded to give the substi-
tuted product in 93% isolated yield. Whilst the coupling
reactions above were performed under nitrogen, they can
also be carried out in air without notable effects on yields.
More recently, we have found that a mixture of benzo-
tri¯uoride and DMSO 010:1, v/v) is even better for this
coupling. Benzotri¯uoride is not expensive, and it dissolves
both the starting materials and products under the reaction
condition. The work up is also made simpler. Thus, pure
product can be easily obtained by ®ltering off the excess
copper and copper salts followed by washing with 1N HCl
and water to remove the remaining copper salts and DMSO
and then drying 0Table 1).
contrast, previous methodologies led to less ef®cient use
of the expensive per¯uoroalkyl iodides.3h,n±p
The compatibility of the method with functional groups
can, to some degree, be judged by the coupling of 2a with
methyl 4-[di04-bromophenyl)phosphinyl]benzoate 5, yield-
ing methyl 4-[di04-per¯uorohexylphenyl)phosphinyl]benzo-
ate 6 in 92% isolated yield. The free phosphine derived from
6 would be amphiphilic and immobilizable.
2.2. Synthesis of ¯uoroalkylated arylphosphines by the
Heck reaction
The direct coupling of per¯uoroalkyl iodides with halo-
arylphosphine oxides mediated by copper is an ef®cient
approach to arylphosphines bearing per¯uorinated pony-
tails. However, this method does not allow one to introduce
an ethylene spacer between the aromatic ring and the
per¯uoroalkyl unit, which is often necessary to reduce the
strong electron-withdrawing effect of the latter. As indicated
above, the previous methods to these ligands have met with
dif®cult separation problems. Since the Heck reaction
provides probably the most convenient way for the ole®na-
tion of aromatic halides, we thought that the coupling of
haloarylphosphine oxides with ¯uorinated ole®ns could
lead to the easy preparation of various ¯uorous aryl-
phosphines containing ethylene spacers.5b In fact, the
preparation of b-tri¯uoromethylstyrene via the Heck
reaction of aryl halides with tri¯uoropropene was reported
two decades ago.11
The phosphines were released from the oxides by reduction
with trichlorosilane.10 The reaction was carried out by
simply heating a mixture of a per¯uoroalkylated phosphine
oxide 3, trichlorosilane, and triethylamine in toluene at
1208C for a few hours, affording the free phosphines 4aa,
ba, ca, and cb in almost quantitative isolated yields 0Table
1). Hence, about 90% of the per¯uoroalkyl reagents can
effectively be incorporated into the desired product. In
Table 1. Synthesis of per¯uoroalkylated arylphosphines via copper-mediated coupling of OPPh32n04-C6H4Br)n with IRf followed by reduction with HSiCl3
Compound
Solvent
n
Rf
Temperature 08C)
Time 0h)
Yield 0%)a
3aa
3ba
3ca
3cb
3cb
3ca
3cb
4aa
4ba
4ca
4cb
DMSO
DMSO
DMSO
DMSO
PFCyb
BTFc
1C
2
3
3
3
3
3
1C
2
3
6F13
C6F13
C6F13
C8F17
C8F17
C6F13
C8F17
6F13
120
120
120
120
110
115
115
120
120
120
120
15
24
36
36
72
24
24
6
95
94
91
45
93
92
93
97
98
98
95
BTFc
Toluene
Toluene
Toluene
Toluene
C6F13
C6F13
C8F17
6
6
6
3
For detailed reaction conditions, see Section 3.
Isolated yield.
a
b
Per¯uoro-1,3-dimethylcyclohexane 0PFCy)1DMSO 010:1, v/v).
Benzotri¯uoride 0BTF)1DMSO 010:1, v/v).
c

3892
W.Chen et al./ Tetrahedron 58 %2002) 3889±3899
Scheme 4. Synthesis of ¯uoroalkylated arylphosphines by the Heck reaction.
To our delight, the oxides 1 could easily be ole®nated with
the ¯uorinated ole®ns 7 to give the ole®nated phosphine
oxides 8 0Scheme 4). In a typical reaction, a phosphine
oxide 1 was mixed with 1.1 equiv. of an ole®n 7 0relative
to bromine), ca. 1.3 equiv. of NaOAc, and 0.5±1 mol% of
the Herrmann±Beller palladacycle catalyst in DMF.12 The
coupling reaction proceeded smoothly at 1258C to give 8 in
more than 90% isolated yields without optimisation 0Table
2). In all the cases, the reaction completed in 24 h reaction
time regardless of the number of bromo groups in the
starting oxide. The OvP substituted phenylbromides thus
behave like an activated arylbromide such as 4-bromo-
acetophenone in the Heck reaction. Activation of bromo-
benzene itself requires more stringent conditions with the
same palladacycle catalyst. This may not be surprising
given the strong electron withdrawing capability of the
OvP moiety.1 3 H1 NMR studies indicate that the electron
withdrawing effect of the phosphoryl group on the para
position of a phenyl ring lies between those of a carbonyl
and a bromide group.9 In line with this argument, tris-
04-bromophenyl)phosphine failed to couple with 7a under
conditions similar to those employed for the corresponding
oxide, although this could also arise from possible poisoning
of active palladium species by the excessive phosphine, and
the borane protected tris04-bromophenyl)phosphine did not
react either with the same ole®n. As with other Heck
reactions, substitution of the vinylinic protons by the aryl-
phosphine oxides occurs at the less substituted side of the
CvC double bond leading to trans ole®ns.
Pd/C catalyst and removal of solvent. The reduction of 9ca
by trichlorosilane afforded the free phosphine 10ca in 96%
isolated yield. Other free phosphines were obtained in
similar yields. Thus, the ethylene spaced, per¯uoroalkylated
arylphosphines could easily be accessed via the Heck reac-
tion, and close to 90% of the per¯uoroalkyl reagents has
been incorporated into the desired product with the present
methodology.
2.3. Synthesis of per¯uoroalkylated BINOLs by the Heck
reaction
The Heck reaction above could also be extended to the
¯uorination of optically active binaphthols 0BINOLs),
which have extensively been used as ligands or building
blocks for ligands in asymmetric catalysis 0Scheme 5).6
Thus in the presence of 0.5 mol% of the palladacycle cata-
lyst, the Heck reaction of 0R)-6,60-dibromo-2,20-dibenzyl-
oxy-1,10-binaphthyl 11 with 7a was complete in 24 h
reaction time at 1258C to give the expected trans substituted
product 12a in 95% isolated yield. Following hydrogenation
by Pd/C to reduce the double bonds and debenzylate at the
same time, the ¯uoroalkylated 0R)-1,10-bi-2-naphthol 13a
was obtained in 86% overall yield. The coupling involving
7b with a longer ¯uorous chain worked equally well, afford-
ing the substituted binaphthol 13b in 82% overall yield.
Whilst the Heck reaction by the palladacycle catalyst gener-
ally requires high temperature and long reaction time with
deactivated arylbromides such as alkoxy substituted bromo-
benzenes,12 the reactivity of the binaphthol derivative 11
appears to be similar to activated aryl bromides.
To obtain the free phosphines 10, the substituted phosphine
oxides 8 were ®rst subjected to hydrogenation and then
reduced by treatment with trichlorosilane as described
above for 4. As an example, the hydrogenation of 8ca cata-
lysed by Pd/C under 10 bar H2 afforded the saturated oxide
The ¯uoroalkylated 0R)-1,10-bi-2-naphthol 13 can be used
for the synthesis of ¯uoroalkylated BINAP.14 Other per-
¯uoroalkylated aromatic building blocks have also been
prepared by us by this methodology.15 In a related develop-
ment, multi-¯uoroalkylated BINOLs were synthesised via
the organolithium mediated reaction of a 6,60-dibromo-1,10-
bi-2-naphthol derivative with a ¯uoroalkylated bromo-
silane16 and the copper mediated coupling of a 4,40,6,60-
tetrabromo-1,10-bi-2-naphthol derivative with a per¯uoro-
alkyl iodide.17
1
9ca. H and 31P NMR spectra of the oxide so obtained
showed no by-products. The oxide can therefore be taken
directly to the next step for reduction after ®ltering off the
Table 2. Heck ole®nation of OPPh32n04-C6H4Br)n with H2CvCHRf
Compound
n
Rf
Time 0h)
Yield 0%)a
8aa
8ba
8ca
8cb
1
2
3
3
C6F13
C6F13
C6F13
C8F17
20
24
24
24
93
94
91
92
2.4. Synthesis of ¯uorous soluble polymeric
arylphosphines
The application of ¯uorous ligands in catalysis in ¯uorous
solvents and scCO2 is often complicated by the ®nite
For detailed reaction conditions, see Section 3.
Isolated yield.
a

W.Chen et al./ Tetrahedron 58 %2002) 3889±3899
3893
Scheme 5. Synthesis of chiral ¯uoroalkylated BINOLs by the Heck reaction.
1
solubility of such ligands in common organic solvents,
which makes catalyst recycle more dif®cult than one
would expect if the ligands could completely be immobi-
lised in one phase. This is particularly true for ¯uoroalkyl-
ated arylphosphines such as P04-C6H4CH2CH2C6F13)3 10ca.
These are more soluble in organic solvents than are ana-
logous per¯uoroalkylphosphines such as P0CH2CH2C6F13)3
and thus less useful in ¯uorous biphasic catalysis.1f
Ironically, it is the former class of phosphines that are far
more extensively used in homogeneous catalysis. In order to
further improve the solubility of arylphosphines in ¯uorous
solvents and scCO2 and reduce their solubility in normal
organic solvents so that easier catalyst/product separation
could be attained, we designed and synthesised ¯uorous
polymer-supported arylphosphines as an alternative to
of resonance due to ole®nic protons in the H NMR spec-
trum. The CvO absorption appeared at 1738 cm21 for 16
and 1740 cm21 for 17 in the IR spectrum. The 31P NMR
spectrum of each polymer in benzotri¯uoride 0containing
5% CDCl3) displayed a relatively sharp singlet at around
d 26.2. Surprisingly, the singlet became much broader in
per¯uoro-1,3-dimethylcyclohexane, with half-height line
width of 200 Hz as opposed to 58 Hz in benzotri¯uoride
for 16. The polymers are soluble in both solvents. One
possible explanation for the line broadening is that in
per¯uorinated solvents the polymers, which contain both
¯uorous-soluble and insoluble segments, may aggregate,
whereas in partly ¯uorinated solvents such as benzotri-
¯uoride such aggregation may not be favoured due to
favourable solvent±solute interactions.19 The phosphorus
content of the polymers was estimated to be 1.2% for 16
and 0.8% for 17 by 31P NMR using bis0diphenylphos-
phino)methane as an internal standard. These values are
close to the value of 1.1 and 0.6% calculated on the basis
of the monomer ratios, and are consistent with the high
yields of polymer synthesis.
¯uorous soluble molecular ligands such as 4 and 10.18
A
¯uoroacrylate copolymer containing alkylarylphosphine
groups has recently been reported and shown to be effective
in rhodium catalysed hydrogenation of ole®ns, while this
work was in progress.3e
The poly[¯uoroacrylate-co-4-0diphenylphosphino)styrene]
ligands 16 and 17 were synthesised by radical copolymeri-
sation of 4-0diphenylphosphino)styrene 14 with 1H,1H,
2H,2H-per¯uorodecylacrylate 15 at 658C in the presence
of AIBN in benzotri¯uoride 0Scheme 6). For the ¯uorous
polymer 16, the molar ratio of 15 to 14 was 5:1. For 17, the
ratio was 9:1. After removal of benzotri¯uoride, the resul-
tant solid was washed with hot toluene, affording the
polymers as white powders in greater than 90% yields.
The IR spectrum of both polymers showed disappearance
of absorptions due to CvC stretching, in line with the lack
As is expected, the ¯uorous soluble polymer-supported aryl-
phosphine ligands are much less soluble in common organic
solvents than are molecular arylphosphines modi®ed with
¯uorous ponytails. This is evident from the approximate
partition coef®cient f shown in Table 3. The partition coef-
®cient is de®ned as the ratio of the weight of a polymer in
¯uorous phase vs that of the same polymer in an organic
solvent under equilibrium conditions. The partition coef-
®cient for 16 is ca. 27 and does not vary signi®cantly with
the organic solvents. In contrast, the values of f for the
Scheme 6. Synthesis of ¯uorous soluble polymer-supported arylphosphines.

3894
W.Chen et al./ Tetrahedron 58 %2002) 3889±3899
Table 3. Partition coef®cients of phosphines in organo-¯uorous phases
Phosphine
Solventa
f b
16
Toluene/PFCy
THF/PFCy
Toluene/PFCy
THF/PFCy
Toluene/PFCy
THF/PFCy
26.9
27.7
4.4
2.2
0.9
P04-C6H4C6F13)3 4ca
P04-C6H4CH2CH2C6F13)3 10ca
0.2
Measured at 248C by ®rst saturating an organo/per¯uorocarbon solvent
mixture with the ligand under question followed by syringing equal volume
solution from the two phases and by weighing the dried and solvent-free
ligand.
a
PFCyˆper¯uoro-1,3-dimethylcyclohexane.
b
fˆweight of ligand in ¯uorous phase/weight of ligand in organo phase.
Scheme 8. Rhodium/4ca-catalysed hydroformylation of alkyl acrylates in
scCO2 0180 bar CO2) and toluene. Reaction conditions: 3.9±6.3 mmol
[Rh0acac)0CO)2], 10 equiv. of 4ca, methyl acrylate concentration 0.45 M,
butyl and t-butyl acrylate concentration 0.28 M, reaction time 1h. For more
details, see Ref. 21b.
molecular ligand P04-C6H4C6F13)3 4ca are much
smaller, and are still smaller for the ethylene-spaced
P04-C6H4CH2CH2C6F13)3 10ca. The latter is in fact more
soluble in the organic solvents than in the per¯uorinated
solvents. Clearly, for ¯uorous biphasic catalysis involving
¯uorous soluble arylphosphine ligands, 16 and 17 would
offer a better choice for retaining a metal catalyst in the
¯uorous phases.
from the per¯uoroalkylated ponytails.1,3 However, our
investigation shows this not to be necessary for hydro-
formylation in scCO2.21c
Our results on the hydroformylation of 1-hexadecene
obtained with arylphosphines containing three differing
ponytails are depicted in Scheme 7. The hydroformylation
reactions in scCO2 were performed for 1h using a combi-
nation of [Rh0acac)0CO)2] and 10 equiv. of a phosphine
ligand at 808C, 20 bar H2/CO 01:1), and 180 bar CO2. As
is evident, the ponytails impose a signi®cant effect on the
activity of rhodium, as can be judged by the average turn-
over frequency 0TOF) to aldehyde. Thus, on going from the
per¯uoroalkylated ligand 4ca to the ethylene-spaced 10ca,
the rates of the hydroformylation decreased ca. 3 times. The
same trend also holds for other 1-alkenes. Hence, it is clear
that insulating spacer groups are not necessary and in fact
bring about detrimental effect on rates in hydroformylation
in scCO2. Because both ligands are soluble and form a
homogeneous solution in scCO2 under the reaction con-
ditions and because they are sterically similar, the observed
decrease in rates can only be attributed to an increase in the
electron richness of the phosphorus in 10ca. In line with this
explanation, the fully alkylated ligand P04-C6H4C6H13)3 18
yielded a still lower TOF, although the low solubility of 18
in scCO2 undoubtedly also contributed to the decreased
TOF. These observations are not surprising. Previous
investigations in conventional solvents have shown that
triarylphosphines and related bidentate ligands bearing
electron-withdrawing substituents tend to give higher rates
and better regioselectivities to linear aldehydes.23 The
regioselectivity of the reactions in Scheme 7, as measured
by the linear/branched 0L/B) aldehyde ratios, did not
increase with increasing electron-withdrawing power of
the ponytails, however.
2.5. Hydroformylation of ole®ns in scCO2
Hydroformylation is one of the most important applications
of homogeneous catalysis in industry. A number of publi-
cations concerning this reaction have appeared, striving for
more active and selective rhodium catalysts coupled with
easy catalyst separation and reuse.2 In this context, scCO2
has proven to be an excellent medium, offering high
reaction rates and the potential of easy catalyst/product
separation.20 Our work in this area has recently been
published.21 We summarise below only the salient aspects
of the observations.
As is well known and evident from the above, ¯uoroalkyl-
ation of common phosphines provides an easy entry into
ligands soluble in scCO2 and per¯uorocarbons.1,3 Indeed,
phosphines bearing ¯uorinated ponytails such as
P0CH2CH2C6F13)3 and 10ca have been shown, when
combined with rhodium, to be effective and recyclable in
hydroformylation in these non-conventional solvents.20d,22
Due to the strong electron-withdrawing effect of the
per¯uoroalkyl substituents, a spacer group such as methyl-
ene units is normally employed to insulate the phosphorus
Our second example concerns the hydroformylation of
acrylic esters in scCO2. This is potentially a synthetically
useful reaction, as it produces bifunctional compounds that
can be used as intermediates for synthesis. However, in
common organic solvents the reaction is in general slow
and high temperature and/or high pressure are often
required.24 In sharp contrast, the reaction is found to be
Scheme 7. Effect of phosphine ligands on rhodium-catalysed hydroformyl-
ation of 1-hexadecene in scCO2. Reaction conditions: 1.5±3.0 mmol
[Rh0acac)0CO)2], 10 equiv. of PAr3, ole®n concentration 0.15 M, reaction
time 1h. 18ˆP04-C6H4C6H13)3. For more details, see Ref. 21c.

W.Chen et al./ Tetrahedron 58 %2002) 3889±3899
3895
fast and regioselective as well when run in scCO2 in the
presence of [Rh0acac)0CO)2] and 4ca 0Scheme 8).21b
ole®ns and the ¯uorous phase. Thus, while the hydroformyl-
ation of 1-hexadecne by Rh-16 gave a TON 0turnover
number, mole of aldehyde formed per mol of rhodium) of
1640 at 1008C and 30 bar H2/CO in a 12 h reaction time, the
reaction with 1-hexene yielded a TON near 140,000 by the
same catalyst at 1008C and 50 bar H2/CO in 58 h.
As can be seen, the average TOFs for the formation of
aldehydes in the hydroformylation of the three acrylates in
scCO2 ranged from 1593 to 1827 h21. For comparison, in
toluene under otherwise identical reactions conditions, the
TOFs were less than 200 h21. The linear aldehyde product
could hardly be detected by GC in these reactions. Thus,
by simply changing the reaction medium from toluene to
scCO2, the TOF values increased ca. 10±20 fold. Such
dramatic enhancement in reaction rates by scCO2 has rarely
been observed before, although the high miscibility of
various gases with CO2 and its excellent transport properties
have often been suggested to be impetus for fast reactions.1a
A further demonstration of the rate enhancement is the
hydroformylation of an equimolar mixture of butyl acrylate
and 1-decene by the same catalyst in scCO2. The TOFs
observed for butyl acrylate and 1-decene were 1511 and
379 h21, respectively. This is remarkable, considering that
in the absence of the acrylate the average TOF for 1-decene
was 2794 h21 under otherwise identical reaction con-
ditions.21c In a similar experiment in toluene, the TOF was
found to be 56 for the acrylate and 24 h21 for 1-decene,
while in the absence of the acrylate the TOF for the latter
ole®n rose to 901. Evidently, the Rh-4ca catalyst is con-
siderably more chemoselective towards the less reactive
acrylates, but it is only in scCO2 in which it becomes highly
active as well!
As indicated earlier, one of the objectives for synthesising
16 and 17 was to lower the miscibility of their metal
complexes with organic solvents such that the catalyst/
product separation and catalyst reuse could be facilitated.
The recyclability of the rhodium catalyst containing the
¯uoropolymer 16 was examined in the hydroformylation
of 1-hexene. At 1008C and 50 bar H2/CO with ole®n/
Rhˆ48,000, three consecutive hydroformylation reactions
were run, giving an excellent combined TON of 70,000 and
an average aldehyde selectivity of 99%. A 1ppm loss of
rhodium accompanied with a 6% decrease in conversion in
the recycle experiment was measured. This loss in rhodium
and in catalyst activity appears to be largely due to the ®nite
miscibility of the substrate/product with the ¯uorous
solvent. At the end of the third run, all the per¯uoromethyl-
cyclohexane had leached to the product phase, thus making
the polymer catalyst partially soluble in the product. By
optimising the operating conditions, e.g. by varying the
organic solvent, the problem of rhodium leach could be
minimised.
In summary, we have devised a generic approach for the
synthesis of arylphosphines that can be applied as soluble
ligands for catalysis in scCO2 and ¯uorous solvents. The
synthesis centres on catalytic C±C coupling chemistry,
and is simpler and more economical than the currently
available methods. The feasibility of the approach is mani-
fested by the various ligands that have been prepared in our
lab. The easy availability of these ligands makes more
feasible to evaluate metal/ligand combinations for catalytic
reactions in such ecologically attractive solvents as scCO2.
Our demonstration of the remarkable difference between
4ca and the ethylene-spaced 10ca in hydroformytaion in
scCO2 serves as a good example.
The promoting effect of CO2 may stem from its possible
speci®c interactions with the solute. The rate-determining
step in the acrylate hydroformylation has been proposed
to be the opening of a thermodynamically stable ®ve-
membered chelate ring formed by the coordination of the
acrylate carbonyl oxygen to rhodium.25 In scCO2, this
opening could be made easy by carbonyl±CO2 donor±
acceptor and Rh±CO2 covalent interactions. Previous
spectroscopic studies have already shown that carbonyl
groups can act as Lewis bases and interact with CO2 acting
as a Lewis acid.26 Such speci®c solvent±solute interactions
have rarely been exploited in catalysis in scCO2 but could
provide a unique means for tuning chemical activity and
selectivity in synthesis in scCO2.
3. Experimental
2.6. Fluorous biphasic hydroformylation with ¯uorous
soluble polymer ligands
3.1. General remarks
All reactions were performed under an inert atmosphere.
Melting points were determined in a capillary tube on a
The applicability of the ¯uorous soluble polymer ligands 16
and 17 was also tested in the hydroformylation of ole®ns
such as 1-alkenes, styrene and acrylates, but under ¯uorous
biphasic conditions 0solvent: hexane±toluene±per¯uoro-
methylcyclohexane, 2:1:2, v/v) instead of using scCO2.
The results have been described before.18 The salient
features of the results are: ®rstly, the activity of the ¯uorous
soluble polymer catalyst Rh-16 and Rh-17 are signi®cantly
higher than that reported for solid polymer- and aqueous
soluble polymer-supported rhodium catalysts.27 Secondly,
as with solid polymer-supported catalysts, the aldehyde
L/B ratio is markedly higher than achievable with similar
P/Rh ratios when using homogeneous rhodium±phosphine
catalysts. Thirdly, smaller ole®ns appear to give higher turn-
overs, probably owning to better miscibility between the
1
Gallenkamp apparatus and were uncorrected. H and 13C
NMR spectra were obtained on a Varian Gemini 300 or a
Bruker Avance 400 spectrometer in CDCl3 with TMS as
internal standard. 31P{1H} NMR spectra were recorded on
a Bruker WM 250 spectrometer in CDCl3 with 85% H3PO4
as external standard. Optical rotations were measured with a
Polaar 2001polarimeter, and MS spectra on a VG7070E
mass spectrometer. Elemental analysis was performed by
Butterworth Laboratories Ltd. Flash chromatography was
performed using ICN Silica 32-63. Toluene and benzo-
tri¯uoride were distilled over CaH2 and P2O5 under nitro-
gen, respectively. 1-Iodoper¯uorohexane 2a, 1-iodoper¯uoro-
octane 2b, 1H,1H,2H-per¯uoro-1-octene 7a, 1H,1H,2H-per-
¯uoro-1-decene 7b, and 1H,1H,2H,2H-per¯uorodecylacrylate

3896
W.Chen et al./ Tetrahedron 58 %2002) 3889±3899
2
4
15 were purchased from Apollo Scienti®c Ltd and used
without further puri®cation. The bromophenylphosphine
oxides OPPh32n04-C6H4Br)n 0nˆ1±3) 1a±c9 and the
Herrmann±Beller Palladacycle were prepared according to
published procedures.12
2JC±Pˆ10.4 Hz), 135.0 0td, JC±Fˆ21.3 Hz and JC±P
ˆ
2.4 Hz), 136.0 0d, JC±Pˆ101.7 Hz); 31P NMR 0CDCl3,
101 MHz): d 25.7 0s); Anal. calcd for C42H12F51PO: C,
32.92; H, 0.79. Found: C, 32.84; H, 0.83; MS 0CI, m/z):
1533 0M111), 1115, 1074, 1054, 1036, 1023.
1
3.2.5. Tris34-per¯uorohexylphenyl)phosphine 34ca). A
mixture of 3ca 02.465 g, 2.0 mmol), trichlorosilane
04.064 g, 30 mmol), triethylamine 04.554 g, 15 mmol), and
toluene 020 ml) was stirred at 1208C for 6 h under nitrogen.
The mixture was cooled to room temperature and further
cooled with an ice bath. Saturated NaHCO3 aqueous solu-
tion 01ml) was added and the mixture stirred for 10 min.
The solution was then ®ltered through a short alumina
column, and washed with hexane. The ®ltrate was evapo-
rated under reduced pressure to afford 4ca as a white solid
02.384 g, 98%). Mp 66±688C; 1H NMR 0CDCl3, 200 MHz):
d 7.42 0dd, 6H, Jˆ8.2 and 7.7 Hz), 7.610d, 6H, Jˆ7.7 Hz);
3.2. Synthesis of ¯uoroalkylated arylphosphine oxides
and the free phosphines
3.2.1. Tris34-per¯uorohexylphenyl)phosphine oxide 33ca).
A mixture of 1c 0515 mg, 1.0 mmol), 2a 01.405 g, 3.2
0
mmol), copper powder 0450 mg, 7.1mmol), 2,2 -bipyridine
034 mg, 0.2 mmol), DMSO 01.0 ml, 14.1 mmol), and benzo-
tri¯uoride 010 ml) was stirred and re¯uxed for 24 h. The
mixture was then cooled to room temperature, ®ltered
through a pad of Celite and washed with CHCl3
02£20 ml). The combined ®ltrates were washed succes-
sively with 1N HCl 02£50 ml), water 050 ml) and brine
030 ml), dried over anhydrous MgSO4, and evaporated
under reduced pressure. The resultant solid was crystallised
from EtOH to give 3ca as colourless needles 01.133 g, 92%).
31P NMR 0CDCl3, 101 MHz): d 26.10s).
4ca has
previously been reported.3p
1
3.2.6. 34-Per¯uorohexylphenyl)diphenylphosphine 34aa).
4aa was prepared from 3aa in the same way as for 4ca in
97% isolated yield. Mp 75±788C; 1H NMR 0CDCl3,
200 MHz): d 7.26±7.62 0m, 14H); 31P NMR 0CDCl3, 1 01
MHz): d 25.3 0s). This compound has also been described
in Ref. 3p.
Mp 136±1388C; H NMR 0CDCl3, 400 MHz): d 7.77 0dd,
6H, Jˆ8.3 and 2.1Hz), 7.84 0dd, 6H, Jˆ11.4 and 8.3 Hz);
3
13C NMR 0CDCl3, 100 MHz): d 127.5 0dt, JC±Pˆ11.6 Hz
3
2
and JC±Fˆ6.6 Hz), 132.3 0d, JC±Pˆ10.2 Hz), 133.4 0dt,
4
1
2JC±Fˆ21.1 Hz and JC±Pˆ2.4 Hz), 135.6 0d, JC±P
ˆ
101.7 Hz);28 31P NMR 0CDCl3, 101 MHz): d 25.6 0s);
Anal. calcd for C36H12F39PO: C, 35.09; H, 0.98. Found: C,
35.35; H, 0.97. In the 13C NMR spectrum of 3ca and those of
others, signals due to carbons of the ¯uorocarbon chains
were too weak to be assigned.
3.2.7. Bis34-per¯uorohexylphenyl)phenylphosphine 34ba).
4ba was prepared from 3ba in the same way as for 4ca as a
colourless oil in 98% isolated yield. 1H NMR 0CDCl3,
200 MHz): d 7.24±7.65 0m, 13H); 31P NMR 0CDCl3, 1 01
MHz): d 25.5 0s). This compound has also been described
in Ref. 3p.
3.2.2. 34-Per¯uorohexylphenyl)diphenylphosphine oxide
33aa). 3aa was prepared from 1a and 2a in the same way as
for 3ca in 95% isolated yield. Mp 121±1238C; H NMR
1
3.2.8. Tris34-per¯uorooctylphenyl)phosphine 34cb). 4cb
was prepared from 3cb in the same way as for 4ca in 95%
isolated yield. Mp 83±868C; 1H NMR 0CDCl3, 400 MHz): d
7.42 0pseudo t or dd, 6H, Jˆ8.0 Hz), 7.62 0d, 6H, Jˆ
8.0 Hz); 31P NMR 0CDCl3, 101 MHz): d 25.5 0s); Anal.
calcd for C42H12F51P: C, 33.27; H, 0.80. Found: C, 33.28;
H, 0.63; MS 0CI, m/z): 1517 0M111), 1037, 1022.
0CDCl3, 400 MHz): d 7.44±7.78 0m, 12H), 7.83 0dd, 2H,
Jˆ11.3 and 8.4 Hz); 13C NMR 0CDCl3, 100 MHz): d 127.3
3
3
3
0dt, JC±Pˆ12.1 Hz and JC±Fˆ6.4 Hz), 128.9 0d, JC±P
ˆ
ˆ
ˆ
3
1
11.6 Hz), 129.1 0d, JC±Pˆ12.7 Hz), 132.0 0d, JC±P
2
2
104.0 Hz), 132.4 0d, JC±Pˆ9.5 Hz), 132.7 0td, JC±F
4
1
21.3 Hz and JC±Pˆ2.4 Hz), 137.9 0d, JC±Pˆ101.1 Hz);
31P NMR 0CDCl3, 101 MHz): d 28.4 0s); Anal. calcd for
C24H14F13PO: C, 48.34; H, 2.37. Found: C, 48.69; H, 2.40.
3.2.9. Methyl 4-[di34-per¯uorohexylphenyl)phosphinyl]-
benzoate 36). 6 was prepared from methyl 4-[di04-bromo-
phenyl)phosphinyl]benzoate 5 and 2a in the same way as for
3ca in 92% isolated yield. Mp 156±1588C; 1H NMR
0CDCl3, 300 MHz): d 3.96 0s, 3H), 7.75 0dd, 4H, Jˆ8.4
and 3.0 Hz), 7.810dd, 4H, Jˆ8.4 and 6.9 Hz), 7.86 0d,
2H, Jˆ8.1Hz), 8.18 0dd, 2H, Jˆ8.1and 3.0 Hz); 13C
3.2.3. Bis34-per¯uorohexylphenyl)phenylphosphine oxide
33ba). 3ba was prepared from 1b and 2a in the same way as
for 3ca in 94% isolated yield. Mp 114±1168C; H NMR
1
0CDCl3, 400 MHz): d 7.51±7.70 0m, 5H), 7.73 0dd, 4H,
Jˆ8.2 and 2.0 Hz), 7.84 0dd, 4H, Jˆ11.4 and 8.2 Hz); 13C
3
NMR 0CDCl3, 100 MHz): d 127.3 0dt, JC±Pˆ12.1 Hz and
3
3
1
3JC±Fˆ6.4 Hz), 129.0 0d, JC±Pˆ12.4 Hz), 130.7 0d, JC±P
ˆ
NMR 0CDCl3, 75 MHz): d 52.6, 127.4 0dt, JC±Pˆ11.4 Hz
3
3
3
2
and JC±Fˆ6.0 Hz), 129.9 0d, JC±Pˆ12.0 Hz), 132.1 0d,
105.5 Hz), 132.0 0d, JC±Pˆ11.0 Hz), 132.4 0d, JC±P
ˆ
2
2JC±Pˆ10.4 Hz), 132.3 0d, JC±Pˆ10.4 Hz), 133.2 0t,
2
4
10.2 Hz), 132.9 0td, JC±Fˆ21.3 Hz and JC±Pˆ2.4 Hz),
1
2JC±Fˆ25.4 Hz), 134.2, 135.6 0d, JC±Pˆ102.7 Hz), 135.9
136.6 0d, JC±Pˆ101.1 Hz); 31P NMR 0CDCl3, 101 MHz):
1
1
0d, JC±Pˆ101.6 Hz), 166.0; 31P NMR 0CDCl3, 101 MHz):
d 26.8 0s); Anal. calcd for C30H13F26PO: C, 39.41; H, 1.43.
Found: C, 38.92; H, 1.30.
d 26.2 0s); MS 0FAB, m/z): 973 0M111), 781, 733, 674,
577; Anal. calcd for C32H15F26O3P: C, 39.53; H, 1.55.
Found: C, 39.10; H, 1.38.
3.2.4. Tris34-per¯uorooctylphenyl)phosphine oxide
33cb). 3cb was prepared from 1c and 2b in the same way
as for 3ca in 93% isolated yield. Mp 138±1408C; 1H NMR
0CDCl3, 400 MHz): d 7.77 0dd, 6H, Jˆ8.3 and 2.1Hz), 7.84
0dd, 6H, Jˆ11.4 and 8.3 Hz); 13C NMR 0CDCl3, 100 MHz):
3.2.10. Tris[4-31H,2H-per¯uoro-1-octenyl)phenyl]phos-
phine oxide 38ca). A mixture of 1c 01.03 g, 2.0 mmol), 7a
02.284 g, 6.6 mmol), palladacycle 056 mg, 0.06 mmol),
NaOAc 0656 mg, 8.0 mmol), and DMF 010 ml) was stirred
3
3
d 128.3 0dt, JC±Pˆ12.1 Hz and JC±Fˆ6.4 Hz), 133.4 0d,

W.Chen et al./ Tetrahedron 58 %2002) 3889±3899
3897
for 24 h at 1258C. Most of DMF was removed under
reduced pressure. The residue was dissolved in CHCl3
0100 ml) and water 0100 ml). The organic layer was sepa-
rated, washed with water 0100 ml) and brine 050 ml), dried
0MgSO4), and evaporated under reduced pressure. The
residue was puri®ed by ¯ash chromatography 0SiO2,
EtOAc±CHCl3, 1:8) to give 8ca as a pale-yellow oil
mixture was ®ltered through a pad of Celite. The ®ltrate
was then evaporated under reduced pressure to give 9ca
1
as a pale-yellow oil 02.630 g, 100%). H NMR 0CDCl3,
300 MHz): d 2.39 0m, 6H), 2.98 0t, 6H, Jˆ7.8 Hz), 7.33
0dd, 6H, Jˆ8.1and 2.4 Hz), 7.63 0dd, 6H, Jˆ11.7 and
8.1Hz); 13C NMR 0CDCl3, 75 MHz): d 26.5, 32.5 0t,
3
2JC±Fˆ29.9 Hz), 128.6 0d, JC±Pˆ12.0 Hz), 131.2 0d,
1
2
02.385 g, 91%). H NMR 0CDCl3, 300 MHz): d 6.310dt,
3H, Jˆ16.2 and 12.0 Hz), 7.22 0d, 3H, Jˆ16.2 Hz), 7.60
1JC±Pˆ104.8 Hz), 132.6 0d, JC±Pˆ9.8 Hz), 143.6; 31P
NMR 0CDCl3, 101 MHz): d 28.0 0s); Anal. calcd for
C42H24F39PO: C, 38.32; H, 1.84. Found: C, 38.46; H, 1.52;
MS 0CI, m/z): 1317 0M111), 1000, 971, 909, 893, 876.
0dd, 6H, Jˆ8.2 and 2.5 Hz), 7.73 0dd, 6H, Jˆ11.6 and
2
8.2 Hz); 13C NMR 0CDCl3, 75 MHz): d 117.6 0t, JC±F
ˆ
ˆ
3
2
23.5 Hz), 127.4 0d, JC±Pˆ12.5 Hz), 132.8 0d, JC±P
1
3.2.15.
Tris[4-31H,1H,2H,2H-per¯uorodecyl)phenyl]-
10.4 Hz), 133.9 0d, JC±Pˆ103.7 Hz), 137.5, 138.5 0t,
3JC±Fˆ9.2 Hz); 31P NMR 0CDCl3, 101 MHz): d 26.8 0s);
Anal. calcd for C42H18F39PO: C, 38.49; H, 1.38. Found: C,
38.24; H, 1.00; MS 0CI, m/z): 1311 0M111), 1041, 967,
926, 890, 873.
phosphine oxide 39cb). 9cb was prepared from 8cb in the
same way as for 9ca in 99% isolated yield. Mp 123±1258C;
1H NMR 0CDCl3, 400 MHz): d 2.40 0m, 6H), 2.97 0t, 6H,
Jˆ7.8 Hz), 7.32 0dd, 6H, Jˆ8.0 and 2.5 Hz), 7.62 0dd, 6H,
Jˆ11.6 and 8.0 Hz); 31P NMR 0CDCl3, 101 MHz): d 28.0
0s). Anal. calcd for C48H24F51PO: C, 35.66; H, 1.50. Found:
C, 35.77; H, 1.28; MS 0FAB, m/z): 1617 0M111), 1247,
1197, 1171, 1093, 1077.
3.2.11. [4-31H,2H-Per¯uoro-1-octenyl)phenyl]diphenyl-
phosphine oxide 38aa). 8aa was prepared from 1a and 7a
in the same way as for 8ca in 93% isolated yield. 1H NMR
0CDCl3, 300 MHz): d 6.30 0dt, 1H, Jˆ16.2 and 12.0 Hz),
7.210d, 1H, Jˆ16.2 Hz), 7.26±7.71 0m, 12H), 7.73 0dd, 2H,
Jˆ11.4 and 8.4 Hz); 13C NMR 0CDCl3, 75 MHz): d 117.0
3.2.16.
Tris[4-31H,1H,2H,2H-per¯uorooctyl)phenyl]-
phosphine 310ca). A mixture of 9ca 0666 mg, 0.5 mmol),
trichlorosilane 0339 mg, 2.5 mmol), triethylamine 0380 mg,
2.75 mmol), and toluene 010 ml) was stirred at 1208C for
5 h. After cooling to room temperature, saturated NaHCO3
aqueous solution 00.5 ml) was added. The mixture was
stirred for 5 min at room temperature, and then ®ltered
through a pad of alumina and washed with toluene
03£15 ml). The ®ltrate was evaporated under reduced
pressure to give 10ca as a white solid 0630 mg, 96%). Mp
2
3
0t, JC±Fˆ23.2 Hz), 127.7 0d, JC±Pˆ12.5 Hz), 128.7 0d,
3JC±Pˆ12.1 Hz), 131.6, 132.1 0d, JC±Pˆ9.8 Hz), 132.3 0d,
2
1JC±Pˆ103.7 Hz), 132.8 0d, JC±Pˆ10.4 Hz), 135.6 0d,
2
1JC±Pˆ103.1 Hz), 136.8, 138.8 0t, JC±Fˆ9.4 Hz); 31P
3
NMR 0CDCl3, 101 MHz): d 27.7 0s); Anal. calcd for
C26H16F13PO: C, 50.18; H, 2.59. Found: C, 49.92; H, 2.43.
3.2.12. Bis[4-31H,2H-per¯uoro-1-octenyl)phenyl]phenyl-
phosphine oxide 38ba). 8ba was prepared from 1b and 7a
in the same way as for 8ca in 94% isolated yield. 1H NMR
0CDCl3, 300 MHz): d 6.310dt, 2H, Jˆ16.1 and 12.0 Hz),
7.23 0d, 2H, Jˆ16.1 Hz), 7.43±7.52 0m, 3H), 7.58 0dd, 4H,
Jˆ8.2 and 2.3 Hz), 7.65±7.68 0m, 2H), 7.73 0dd, 4H,
Jˆ11.6 and 8.2 Hz); 13C NMR 0CDCl3, 75 MHz): d 117.5
1
69±728C; H NMR 0CDCl3, 400 MHz): d 2.37 0m, 6H),
2.92 0m, 6H), 7.19 0d, 6H, Jˆ7.9 Hz), 7.26 0d, 6H,
Jˆ7.9 Hz); 13C NMR 0CDCl3, 100 MHz): d 26.6, 33.10t,
3
2
2JC±Fˆ22.1Hz), 128.9 0d, JC±Pˆ7.0 Hz), 134.5 0d, JC±P
ˆ
19.8 Hz), 135.9 0d, JC±Pˆ10.8 Hz), 140.3; 31P NMR
0CDCl3, 162 MHz): d 26.8 0s). This compound was ®rst
reported by Leitner and Koch.20d,3b
1
2
3
0t, JC±Fˆ23.1Hz), 128.0 0d, JC±Pˆ12.2 Hz), 129.1 0d,
3JC±Pˆ12.2 Hz), 132.1 0d, JC2±Pˆ103.3 Hz), 132.6 0d,
1
2JC±Pˆ9.6 Hz), 132.7, 133.0 0d, JC±Pˆ10.1 Hz), 133.5 0d,
1JC±Pˆ103.1 Hz), 137.4, 138.9 0t, 3JC±Fˆ9.4 Hz); 31P NMR
3.3. Synthesis of ¯uoroalkylated BINOLs
3.3.1. 3R)-6,60-Bis31H,2H-per¯uoro-1-octenyl)-2,20-di-
benzyloxy-1,10-binaphthyl 312a). A solution of 0R)-6,60-
dibromo-2,20-dibenzyloxy-1,10-binaphthyl 11 01.24 g,
2 mmol), 7a 01.73 g, 5 mmol), Hermman's palladacycle
catalyst 019 mg, 0.02 mmol), and NaOAc 0410 mg,
5 mmol) in DMF 010 ml) was stirred for 24 h at 1258C.
After cooling to ambient temperature, the solvent was
removed under reduced pressure, and the residue was par-
titioned between EtOAc 050 ml) and water 050 ml). The
organic layer was separated, washed with water 050 ml)
and brine 050 ml), dried 0MgSO4), and evaporated under
reduced pressure. The residue was puri®ed by ¯ash chroma-
tography 0SiO2, hexane±EtOAc, 8:1) to give 12a as a pale-
0CDCl3, 101 MHz):
d
C34H17F26PO: C, 42.26; H, 1.77. Found: C, 42.38; H, 1.64;
28.5 0s); Anal. calcd for
MS 0CI, m/z): 967 0M111), 546.
3.2.13. Tris[4-31H,2H-per¯uoro-1-decenyl)phenyl]phos-
phine oxide 38cb). 8cb was prepared from 1c and 7b in
the same way as for 8ca in 92% isolated yield. H NMR
1
0CDCl3, 300 MHz): d 6.32 0dt, 3H, Jˆ16.2 and 12.0 Hz),
7.23 0d, 3H, Jˆ16.2 Hz), 7.60 0dd, 6H, Jˆ8.2 and 2.5 Hz),
7.73 0dd, 6H, Jˆ11.6 and 8.2 Hz); 13C NMR 0CDCl3,
2
3
75 MHz): d 117.6 0t, JC±Fˆ23.5 Hz), 128.0 0d, JC±P
ˆ
ˆ
2
1
12.7 Hz), 133.0 0d, JC±Pˆ10.4 Hz), 134.1 0d, JC±P
103.7 Hz), 137.6, 138.8 0t, JC±Fˆ9.2 Hz); 31P NMR
0CDCl3, 101 MHz): d 26.9 0s). MS 0FAB, m/z): 1611
0M111), 1167, 799, 723.
3
1
yellow glass-like solid 02.19 g, 95%). H NMR 0CDCl3,
300 MHz): d 5.09 0s, 4H), 6.19 0dt, 2H, JH±Hˆ16.2 Hz
and JF±Hˆ12.1 Hz), 6.97 0dd, 2H, Jˆ7.4 and 1.7 Hz),
7.05±7.18 0m, 12H), 7.36 02H, dd, Jˆ8.8 and 1.6 Hz),
7.45 0d, 2H, Jˆ9.1Hz), 7.92 0s, 2H), 7.96 0d, 2H, Jˆ
9.1Hz); 13C NMR 0CDCl3, 75 MHz): d 71.3, 113.9 0t, Jˆ
23.4 Hz), 116.0, 120.6, 124.1, 126.5, 126.9, 127.8, 128.6,
129.4, 129.9, 130.6, 135.3, 137.5, 140.1, 155.7; Anal. calcd
3.2.14.
Tris[4-31H,1H,2H,2H-per¯uorooctyl)phenyl]-
phosphine oxide 39ca). A mixture of 8ca 02.611 g,
2.0 mmol), 10% Pd/C 050 mg), and EtOAc 040 ml) was
stirred for 5 h at room temperature under 10 bar of
hydrogen. After carefully releasing the hydrogen, the

3898
W.Chen et al./ Tetrahedron 58 %2002) 3889±3899
for C50H28F26O2: C 52.02, H 2.44. Found: C 52.41, H 2.18;
MS 0FAB, m/z): 1154 0M1), 1063, 973, 890, 810;
with an ice bath. The solid was collected by ®ltration and
washed with toluene 02£20 ml) to give poly[¯uoroacrylate-
co-4-0diphenylphosphino)styrene] 17 as white powder
04.55 g, 92%). The phosphorus content of the polymers
was estimated to be 0.8% by 31P NMR using bis0diphenyl-
phosphino)methane as an internal standard. Anal. calcd for
C137H80F153O18P: C, 33.23; H, 1.63. Found: C, 33.71; H,
1.69; 31P NMR 0C6H5CF3±CDCl3, 101 MHz): d 26.2 0s).
10
[a]D ˆ260.8 0c 1.5, CHCl3).
3.3.2. 3R)-6,60-Bis31H,2H-per¯uoro-1-decenyl)-2,20-di-
benzyloxy-1,10-binaphthyl 312b). 12b was prepared from
11 and 7b in the same way as for 12a in 92% isolated yield.
Mp 86±888C; 1H NMR 0CDCl3, 300 MHz): d 5.09 0s, 4H),
6.19 0dt, 2H, JH±Hˆ16.0 Hz and JF±Hˆ12.5 Hz), 6.98 0dd,
2H, Jˆ7.4 and 1.6 Hz), 7.07±7.18 0m, 12H), 7.36 0dd, 2H,
Jˆ9.1and 1.6 Hz), 7.45 0d, 2H, Jˆ9.1Hz), 7.92 0s, 2H),
7.95 0d, 2H, Jˆ9.1Hz); 13C NMR 0CDCl3, 75 MHz): d
71.0, 113.6 0t, Jˆ23.5 Hz), 116.4, 120.4, 123.8, 126.3,
126.2, 127.5, 128.3, 129.1, 129.6, 130.3, 135.0, 137.2,
139.8, 155.4; Anal. calcd for C54H28F34O2: C, 47.88; H,
2.08. Found: C, 48.06; H, 1.98; MS 0FAB, m/z): 1354
The polymer 16 was prepared in a similar way in 93% yield,
starting from 14 and 15 with a molar ratio of 1:5. The phos-
phorus content of the polymers was estimated to be 1.2%.
Anal. calcd for C85H52F85O10P: C, 35.46; H, 1.82. Found: C,
35.17; H, 1.75; 31P NMR 0C6H5CF3±CDCl3, 101 MHz): d
26.2 0s).
0M1), 1263, 1173, 1139, 910, 819; [a]D ˆ259.5 0c 1.6,
20
CHCl3).
Acknowledgements
3.3.3.
3R)-6,60-Bis31H,1H,2H,2H-per¯uorooctyl)-2,20-
We thank the EPSRC and the University of Liverpool
Graduates Association 0Hong Kong) for postdoctoral
research fellowships 0W. C., L. X., Y. H.) and the
Leverhulme Centre for Innovative Catalysis 0LCIC) for a
studentship 0A. M. B. O.). Support from the industrial part-
ners 0Synetix, Johnson Matthey, Catalytica, Air Products,
Syntroleum) of the LCIC is also gratefully acknowledged.
J. X. is particularly grateful to Synetix for the support of a
Readership.
dihydroxy-1,10-binaphthyl 313a). A mixture of 12a
01.73 g, 1.5 mmol), 10% Pd/C 0400 mg), and EtOAc
010 ml) was stirred overnight at room temperature under
30 bar of hydrogen. After carefully releasing the hydrogen,
the mixture was ®ltered through a pad of Celite. The ®ltrate
was evaporated under reduced pressure. The resulting
residue was puri®ed by ¯ash chromatography 0SiO2,
hexane±EtOAc, 2:1) to give 13a as a pale-yellow oil,
which crystallised on standing 01.34 g, 91%). Mp 133±
1
1358C; H NMR 0CDCl3, 300 MHz): d 2.43 0m, 4H), 3.04
0m, 4H), 5.010s, 2H), 7.10 0d, 2H, Jˆ8.5 Hz), 7.17 0d, 2H,
Jˆ8.5 and 1.9 Hz), 7.39 0d, 2H, Jˆ8.8 Hz), 7.73 0s, 2H),
7.94 0d, 2H, Jˆ8.8 Hz); 13C NMR 0CDCl3, 75 MHz): d
26.7, 33.10t, Jˆ22.2 Hz), 111.2, 118.6, 125.2, 127.6,
128.6, 130.1, 131.4, 132.6, 135.2, 153.0; Anal. calcd for
C36H20F26O2: C 44.19, H 2.06. Found: C 44.58, H 1.85;
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