Chiral fluorous phosphorus ligands based on the binaphthyl skeleton: Synthesis and applications in asymmetric catalysis

Article abstract of DOI:10.1016/S0957-4166(03)00435-X

Two enantiopure fluorous phosphines have been conveniently synthesized by combining palladium-catalyzed coupling reactions of easily available binaphthyl building-blocks with the introduction of fluorous ponytails onto aromatic compounds via ether bond fo

Full text of DOI:10.1016/S0957-4166(03)00435-X

TETRAHEDRON:
ASYMMETRY
Pergamon
Tetrahedron: Asymmetry 14 (2003) 2215–2224
Chiral fluorous phosphorus ligands based on the binaphthyl
skeleton: synthesis and applications in asymmetric catalysis
Jeroˆme Bayardon,a Marco Cavazzini,b David Maillard,a Gianluca Pozzi,b,* Silvio Quicib and
Denis Sinoua,*
aLaboratoire de Synthe`se Asyme´trique, associe´ au CNRS, CPE Lyon, Universite´ Claude Bernard Lyon 1,
43, boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex, France
bCNR-Istituto di Scienze e Tecnologie Molecolari, via C. Golgi 19, 20133 Milano, Italy
Received 6 May 2003; accepted 13 May 2003
Abstract—Two enantiopure fluorous phosphines have been conveniently synthesized by combining palladium-catalyzed coupling
reactions of easily available binaphthyl building-blocks with the introduction of fluorous ponytails onto aromatic compounds via
ether bond formation. These new fluorous chiral phosphines have been tested as ligands in metal-catalyzed asymmetric
transformations, the best results being obtained in the palladium-catalyzed asymmetric allylic substitution of 1,3-diphenyl-2-pro-
penyl acetate affording the products of up to 87% e.e.
© 2003 Elsevier Ltd. All rights reserved.
1. Introduction
the presence of fluorous chiral salen manganese com-
plexes,6 hydrolytic kinetic resolution of terminal epox-
ides using fluorous chiral Co(salen) complexes,7
asymmetric alkylation of aldehydes with fluorous
BINOL titanium alkoxides,8 reduction of ketones via
hydrogen transfer reactions in the presence of iridium
complexes of fluorous diimines and diamines,9 ruthe-
nium-catalyzed hydrogenation of dimethyl itaconate,10
Heck reactions,11 and palladium-catalyzed alkylations
of allylic acetates.12
Homogeneous organometallic asymmetric catalysis is
now a powerful tool for the preparation of a large
number of non-racemic chiral compounds.1 However,
the separation of the usually costly and sometimes
toxic catalyst from the product(s) of the reaction is
still problematic. In order to solve this problem, the
use of novel reaction media such as supercritical
fluids,2 ionic liquids,3 and liquid biphasic systems4 is
now thoroughly investigated. These new media not
only offer the possibility of cleaner technology, but
can also promote new selectivities.
Enantiopure
2-(diphenylphosphino)-2%-alkoxy-1,1%-
binaphthyls (MOPs) are useful ligands for several
metal-catalyzed asymmetric transformations.13 We
have recently described the synthesis and some possi-
ble applications in catalysis of MOP analogues char-
acterized by the presence of different fluorous
ponytails in selected positions on the MOP scaf-
fold.12a,b Promising results were obtained in the palla-
Following the pioneering work of Horva´th and Ra´bai
on fluorous biphase systems,5 various homochiral
fluorous organometallic complexes have been reported
in the last few years for use in asymmetric catalysis
in liquid-liquid fluorous solvent/organic solvent sys-
tems, or even under homogeneous conditions in
partly fluorinated solvents such as benzotrifluoride.
Literature examples include epoxidation of alkenes in
dium-catalyzed
asymmetric
alkylation
of
1,3-diphenylprop-2-enyl acetate, for which ligand (R)-
1 (Fig. 1) afforded enantioselectivities up to 87%.12a
We report here a more complete investigation con-
cerning this ligand and the extension of the method-
ology for the introduction of fluorous ponytails
successfully applied in the case of (R)-1 to the prepa-
ration of the fluorous BINAP analogue (R)-2 (Fig.
1).
* Corresponding author. Tel.: 33 (0) 4 72 44 81 83; fax: 33 (0) 4 78 89
89 14; e-mail: sinou@univ-lyon1.fr
0957-4166/$ - see front matter © 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/S0957-4166(03)00435-X

2216
J. Bayardon et al. / Tetrahedron: Asymmetry 14 (2003) 2215–2224
prepared according to the multi-step procedures shown
in Schemes 1 and 2. In both cases, the required fluorous
ponytails were introduced through O-alkylation of pre-
formed polyhydroxy chiral phosphines, according to a
methodology developed by us in the achiral series.14
This approach is particularly convenient due to its
simplicity and flexibility. When applied to the prepara-
tion of 1,1%-binaphthyl-based phosphorus ligands, it
also offers a wider choice of possible locations for the
fluorous ponytails, which can be inserted both onto the
binaphthyl moiety and onto the other phosphorus
substituents.
Figure 1.
The preparation of enantiopure fluorous phosphine
(R)-1 was successfully accomplished by a five-step pro-
cedure (Scheme 1). Bis(4-methoxyphenyl)phosphine
oxide 3 was obtained in 70% yield by reaction of
(4-methoxy-benzene)magnesium bromide with N,N-
2. Results and discussion
The fluorous chiral phosphorus ligands (R)-1 and (R)-
2, analogues of MOP and BINAP, respectively, were
Scheme 1. Reagents and conditions: (i) (4-MeOC6H4)2POH (3), Pd(OAc)2, dppb, (i-Pr)2NEt, DMSO, 120°C, 12 h; (ii) BBr3,
CH2Cl2, 0°C, 2 h; (iii) aqueous NaOH 3 M, MeOH/dioxane 2:1, 25°C, 24 h; (iv) C7F15CH2OSO2C4F9, Cs2CO3, DMF, 100°C, 8
h; (v) HSiCl3, toluene, 110°C, 3 h.
Scheme 2. Reagents and conditions: (i) HSiCl3, toluene, 110°C, 8 h; (ii) (4MeO-C6H4)2POH (3), Pd(OAc)2, dppb, DMSO,
(i-Pr)2NEt, 120°C, 24 h; (iii) H2O2 10%, acetone, rt, 8 h; (iv) (2R,3R)-2,3-di-O,O-benzoyltartaric acid, toluene, CHCl3, AcOEt; (v)
BBr3, CH2Cl2, 0°C to rt, 24 h; (vi) C7F15CH2OSO2C4F9, Cs2CO3, DMF, 120°C, 24 h; (vii) HSiCl3, xylene, 125°C, 48 h.

J. Bayardon et al. / Tetrahedron: Asymmetry 14 (2003) 2215–2224
2217
oxide (R)-13 with trichlorosilane in boiling xylene,18
a
procedure currently employed for the reduction of
enantiomerically pure BINAPOs,20 afforded the corre-
sponding pure fluorous BINAP (R)-2 in 48% yield.
diethyl-phosphoramidous dichloride Cl2PNEt2 at
−10°C followed by acidic hydrolysis at −10°C, accord-
ing to a one-pot procedure based on similar methods
reported in the literature.15 The condensation of the
bis(trifluoromethanesulfonate) of binaphthol (R)-4 with
phosphine oxide 3 in the presence of 10 mol%
Pd(OAc)2 and 10 mol% of 1,4-bis(diphenylphosphino)
butane (or dppb) in DMSO at 120°C16 afforded com-
pound (R)-5, resulting from a monophosphinylation
reaction, in 96% yield. Subsequent cleavage of the
methyl group of the phosphinyl derivative (R)-5 with
BBr3 in CH2Cl2 at 0°C17 led to the dihydroxy derivative
(R)-6 in quantitative yield after recrystallization from
diethyl ether. Hydrolysis of the remaining triflate group
with aqueous sodium hydroxide in a methanol/dioxane
mixture converted compound (R)-6 into (R)-2-[bis(4-
hydroxyphenyl) phosphinyl]-2%-hydroxy-1,1%-binaphthyl
(R)-7 in 92% yield. Reaction of binaphthyl derivative
(R)-7 with 1H,1H-pentadecafluorooctan-1-ol nona-
fluorobutane sulfonate in DMF at 100°C in the pres-
ence of caesium carbonate14 allowed the introduction of
three fluorous ponytails; phosphine oxide (R)-8 was
obtained in 70% yield after simple flash chromatogra-
phy. Finally reduction of phosphine oxide (R)-8 with
trichlorosilane in boiling toluene18 afforded the corre-
sponding pure fluorous MOP (R)-1 (having 52.4%
fluorine content) in 91% yield.
In order to check the enantiomeric purity of compound
(R)-13, the corresponding racemic form ( )-13 was also
prepared from ( )-11 according to the above-mentioned
procedure. Comparative 1H NMR titration experiments
involving ( )-13 and (R)-13 were then performed (Fig.
2). In the presence of increasing amounts of (2R,3R)-
2,3-di-O,O-benzoyltartaric acid as resolving agent,
remarkable splitting of the doublet at l 6.69 ppm and
of the broad triplet at l 6.89 ppm were observed for
Gladiali et al. described the preparation of 2-
diphenylphosphino-2%-diphenylphosphinyl-1,1%-binaph-
thalene
(BINAPO)
through
two
subsequent
palladium-catalyzed coupling reaction.19 Their findings
and the good results obtained in the synthesis of (R)-1
led us to investigate the synthetic route to fluorous
phosphine BINAP (R)-2 described in Scheme 2. The
racemic monophosphinyl derivative ( )-5, obtained
from the bistriflate of racemic binaphthol as described
above for the (R)-enantiomer, was converted into the
diarylphosphino triflate ( )-9 in 74% yield by reduction
with trichlorosilane in boiling toluene.18 This allowed a
further palladium-catalyzed coupling reaction between
phosphine ( )-9 and bis(4-methoxyphenyl)phosphine
oxide 3 to proceed at 120°C in dry DMSO using
Pd(OAc)2/dppb as the catalyst.16 The diarylphos-
phinodiarylphosphinyl derivative ( )-10 obtained in
41% yield, was readily oxidized to the racemic diphos-
phine oxide ( )-11 in 96% yield in the presence of H2O2.
Reaction of racemic ( )-11 with (2R,3R)-2,3-di-O,O-
benzoyltartaric acid afforded a solid that was dissolved
in CHCl3 and washed several times with NaOH to give
enantiopure (R)-11 in 74% yield. A similar procedure
has been previously described for the resolution of
closely related diphosphine oxides.20 Cleavage of the
four methyl groups of the diphosphine oxide (R)-12
was performed as above with BBr3 in CH2Cl2 at 0°C17
to afford the tetrahydroxy-binaphthyl derivative (R)-11
in 95% yield. Four fluorous ponytails were then intro-
duced by reaction of (R)-12 with 1H,1H-pentade-
cafluorooctan-1-ol nonafluorobutanesulfonate in DMF
at 120°C in the presence of cesium carbonate;14 diphos-
phine oxide (R)-13 was obtained in 42% yield after
column chromatography. Reduction of phosphine
Figure 2. 1H NMR spectra of ( )-13 (5.8 mmol, A) and (R)-13
(5.8 mmol, B) in the presence of increasing amount of
(2R,3R)-2,3-di-O,O-benzoyltartaric acid: (a) no addition; (b)
2.2 mmol; (c) 3.3 mmol; (d) 4.4 mmol; (e) 6.6 mmol; solvent:
acetone-d6 (0.75 ml).

2218
J. Bayardon et al. / Tetrahedron: Asymmetry 14 (2003) 2215–2224
acetate 14 with various nucleophiles using standard
solvents (Table 1). The reaction of racemic acetate 14
with dimethyl malonate catalyzed by [Pd(C3H5)Cl]2 (2
mol%) in the presence of ligand (R)-1 (8 mol%),
bis(trimethylsilyl)acetamide (BSA, 2 equiv.) and potas-
sium acetate (10.1 equiv.) proceeded quantitatively in
benzotrifluoride at 25°C to give, after 35 h, the corre-
sponding alkylated product 15 with 81% e.e. (Table 1,
entry 2); this value is quite close to that obtained (88%
e.e.) using toluene as the solvent (Table 1, entry 1). It is
noteworthy that the original non-fluorous MOP gave
the alkylated product in 95% yield and 99% e.e. using
toluene as the solvent.21
( )-13, whereas multiplicity of those signals remained
unchanged in the case of (R)-13, thus showing that the
enantiomeric purity of the latter was at least 95%.
Another synthetic way was also studied in order to
circumvent the resolution step in the synthesis of (R)-
13. Reduction of (R)-5 with HSiCl3 in toluene at 110°C
afforded (R)-9 in 88% yield. Condensation of bis(4-
methoxyphenyl)phosphine oxide 13 with phosphine
(R)-9 gave compound (R)-10 in 46% yield, that was
quantitatively oxidized to the diphosphine oxide (R)-13.
Unfortunately, some racemization occurred during this
sequence, since the specific rotation of the obtained
compound was [h]2D0 +21.6 (c 1, CHCl3), lower than the
value obtained using the resolution sequence: [h]D20
+107.6 (c 1, CHCl3).
Reaction of 14 with various substituted dimethyl mal-
onate gave lower chemical yields. Dimethyl methyl-
malonate gave the expected alkylated product with 7%
yield only and 77% e.e. at room temperature, whereas
performing the reaction at 50°C increased the yield to
69% after 48 h, but lowered the e.e. to 44% e.e. (Table
1, entries 4 and 5). Diethyl acetamidomalonate also
gave the alkylated product in very low yield at room
temperature (9%), the yield increasing to 67% when the
reaction was performed at 50°C, the enantioselectivity
being 85% (Table 1, entries 6 and 7). A quantitative
chemical yield was obtained when acetylacetone was
used as the nucleophile, the enantioselectivity being as
high as 81% (Table 1, entry 3). Amines were also used
as nucleophiles in this reaction; morpholine gave only
10% conversion with a very low enantioselectivity (7%
e.e.), when benzylamine gave no reaction at all (Table
1, entries 8 and 9).
In order to use phosphines (R)-1 and (R)-2 as ligands
in organometallic catalysis in a two-phase system
organic solvent/fluorous solvent, the partition coeffi-
cients between FC-72 (perfluoromethylcyclohexane)
and various organic solvents were determined. For
phosphine (R)-1 with a fluorine content of 52.4%, the
values for CH2Cl2, toluene, CH3OH, and CH3CN, were
0.20, 0.23, 7.42, and 11.05, respectively. For phosphine
(R)-2 with a fluorine content of 51.5%, the values for
toluene, ethanol, and acetonitrile, were 0.08, 3.1, and
1.8, respectively. This affinity of the two fluorous phos-
phines for organic solvent is probably due to their
relatively low fluorine content and also to the presence
of an aromatic backbone.
The new fluorous ligands were tested at first under
homogeneous conditions in the palladium-catalyzed
asymmetric allylic alkylation of 1,3-diphenylprop-2-enyl
The fluorous nature of the catalyst allowed its quick
and effective separation from reaction mixtures, as
Table 1. Asymmetric alkylation of 1,3-diphenylprop-2-enyl acetate (14) using various nucleophiles
Entry
Ligand
Nu-H
Solvent
T (°C)
Time (h)
Conversion (%)a
E.e. (%)a (Config.)b
c
c
1
2
3
4
5
6
7
8
(R)-7
(R)-7
(R)-7
(R)-7
(R)-7
(R)-7
(R)-7
(R)-7
(R)-7
(R)-13
(R)-13
(R)-13
(R)-13
CH2(CO2Me)2
CH2(CO2Me)2
C6H5CH3
C6H5CF3
C6H5CF3
C6H5CF3
C6H5CF3
C6H5CF3
C6H5CF3
C6H5CF3
C6H5CF3
C6H5CF3
THF
25
25
25
25
50
25
50
50
50
50
50
50
50
25
36
1
88
<99 (88)
100
7
69
9
67
10
0
12
100
20
20
87 (R)
81 (R)
85 (R)
77 (S)
44 (S)
n.d.e
85 (S)
7
–
14 (R)
32 (R)
37 (R)
25 (R)
c
CH2(COCH3)2
c
c
MeCH(CO2Me)2
MeCH(CO2Me)2
AcNHCH(CO2Me)2
AcNHCH(CO2Me)2
Morpholinec
48
48
21
25
44
24
23
3
c
c
9
Benzylaminec
CH2(CO2Me)2
CH2(CO2Me)2
CH2(CO2Me)2
c
10
11
11bis
12
d
d
THF
16
160
d
CH2(CO2Me)2
D-100f/CH3CN
a Determined by HPLC analysis (column Chiralpak AD 0.46×25 cm).
b Determined by comparison with an authentic sample.
c Base: N,O-bis-(trimethylsilyl)acetamide (BSA)
d Base: NaH
e Not determined
f A mixture of perfluorooctanes

J. Bayardon et al. / Tetrahedron: Asymmetry 14 (2003) 2215–2224
2219
shown in the case of the alkylation of 14 with dimethyl
malonate when toluene was used as the solvent. A
simple liquid-liquid extraction of the organic phase with
FC-72 (2×5 ml) led to the complete removal of the
fluorous palladium complex, as revealed by the absence
The reaction was quantitative using 4-chlorophenyl
triflate (Table 2, entry 2), 2-(4-chlorophenyl)-2,3-dihy-
drofuran being formed with a very high selectivity
(97%) and 68% enantioselectivity. These results com-
pare favorably to those obtained using the parent
BINAP ligand in the same solvent (yield 67%, selectiv-
ity 92%, e.e. 76%), but the observed e.e. was lower than
that achieved using a fluorous BINAP ligand bearing
fluorous ponytails in the 6,6%-positions of the binaph-
thyl moiety (yield 59%, selectivity 88%, e.e. 90%).11
Condensation of phenyl triflate with dihydrofuran
occurred with a lower reaction rate (only 56% conver-
sion after 138 h) (Table 2, entry 1), but with a high
regioselectivity (95%) and the same enantioselectivity
(68% e.e.). The reaction between naphthyl triflate and
dihydrofuran gave the condensation product with a
lower regioselectivity (only 74% of 2-naphthyl-2,3-dihy-
drofuran) and also a lower enantioselectivity (14% e.e.)
(Table 2, entry 4). As expected, condensation of dihy-
drofuran with 4-methoxyphenyl triflate gave a very low
conversion (11%) (Table 2, entry 3). We also tried to
react dihydrofuran and 4-chlorophenyl triflate in a tolu-
ene/FC-72 biphasic system; unfortunately no reaction
occurred after 72 h.
1
of phosphine resonances in the H NMR of the crude
product. However, the recovered fluorous solution did
not show any catalytic activity when tested in a second
run. A similar behavior was previously observed in the
allylation of benzaldehyde catalyzed by platinum com-
plexes of achiral light fluorous phosphines.22
The catalytic alkylation of racemic acetate 14 with
dimethyl malonate using (R)-2 as the ligand was also
performed. The conversion (12%) and the enantioselec-
tivity (14% e.e.) were low when the reaction was carried
out in benzotrifluoride at 50°C in the presence of BSA
as the base (Table 1, entry 10). Although no reaction
occurred when the reaction was performed in THF in
the presence of BSA, the conversion was quantitative
after 3 h when the reaction was run in the presence of
NaH, the enantioselectivity being rather low (32% e.e.)
(Table 1, entry 11). In this latter experiment, the
fluorous catalyst was separated by liquid-liquid extrac-
tion of the reaction mixture using FC-72 as the solvent.
The recovered catalyst gave a lower conversion after 16
h (20%), but the enantioselectivity was the same (Table
1, entry 11bis). Finally the use of (R)-2 as a ligand in a
fluorous biphasic system perfluorooctane/CH3CN at
50°C gave a very low conversion (20%) after 160 h,
with an enantioselectivity up to 25% (Table 1, entry 12).
Finally, fluorous BINAP (R)-2 was tested as a ligand in
two other standard catalytic reactions. Reduction of
a-acetamidocinnamic acid methyl ester (Eq. (1)) was
performed in THF at room temperature under hydro-
gen (13 bar pressure) using the rhodium complex pre-
pared from [Rh(COD)2]BF4 (1 mol%) and (R)-2 (2.2 or
1.2 mol%) at 50°C for 1 h; complete conversion was
observed after 18h, the enantioselectivity being 15 and
16% using 2.2 and 1.2% ligand, respectively.
It was reported that Pd(OAc)2/BINAP catalyzed the
asymmetric Heck reaction between 2,3-dihydrofuran
and aryl triflates at 40°C to give the corresponding
2-aryl-2,3-dihydrofuran in 91% e.e.;23 a fluorous chiral
BINAP analogue recently used by Nakamura and co-
workers afforded enantioselectivity up to 93% for the
same reaction.11 It was obviously interesting to com-
pare the new BINAP analogue (R)-2 to these literature
examples. The reaction was thus carried out in ben-
zotrifluoride, in the presence of Pd(OAc)2 (3 mol%)
associated with (R)-2 (7 mol%). The results are summa-
rized in Table 2.
(1)
Hydroboration of styrene, followed by oxidation, was
also performed (Eq. (2)). Reaction of catechol borane
with styrene in the presence of [Rh(COD)2]BF4 (1
Table 2. Asymmetric Heck reaction of 2,3-dihydrofuran with various aryl triflates
Entry
Ar-OTf
Solvent
Time (h)
Conversion (%)a Ratio 16/17a
E.e. of 16 (%)b (config)c
1
2
3
4
5
C6H5OTf
4-Cl-C6H4OTf
4-CH3O-C6H4OTf C6H5CF3
1-Naphthyl
C6H5CF3
C6H5CF3
138
89
118
120
72
56
100
11
96
0
95/5
97/3
–
74/26
–
68 (R)
54 (R)
–
C6H5CF3
C6H5CH3/FC-72 (1/1)
14d
–
4-Cl-C6H4OTf
a Determined by GC analysis (column Quadrex 30m×0.25 mm).
b Determined by GC analysis (Ar=C6H5 and 4-Cl-C6H4) (column Cydex B 25m×0.25 mm) and HPLC analysis (Ar=naphthyl) (column Chiralpak
AD 0.46×25 cm).
c Determined by comparison of the specific rotation with literature data.
d Not determined.

2220
J. Bayardon et al. / Tetrahedron: Asymmetry 14 (2003) 2215–2224
mol%) and (R)-2 (1 mol%) in THF at room tempera-
ture for 18 h, followed by oxidation with hydrogen
peroxide in the presence of sodium hydroxide, gave
60% conversion in a 86/14 mixture of 1-phenylethanol
and 2-phenylethanol, the enantioselectivity for 1-
phenylethanol being 40% (R). Extraction of the
fluorous rhodium catalyst before oxidation using FC-72
gave a catalyst solution having a very low activity (16%
conversion after 24 h).
4. Experimental
4.1. General
Solvents were purified by standard methods and dried if
necessary. All commercial available reagents were used
as received. All reactions were monitored by TLC (TLC
plates GF254 Merck); detection was effected by UV
absorbance. Air- and moisture-sensitive reactions were
performed under usual inert atmosphere techniques.
Reactions involving organometallic catalysis were car-
ried out in a Schlenk tube under an inert atmosphere.
Column chromatography was performed on silica gel
60 (230-240 mesh, Merck). Optical rotations were
recorded using a Perkin–Elmer 241 polarimeter. NMR
spectra were recorded with Bruker AMX 300 spectrom-
(2)
1
eter and referenced as following: H (300 MHz), inter-
nal SiMe4 at l 0.00 ppm, 13C (75 MHz), internal CDCl3
at l 77.23 ppm, 19F (282 MHz), external CFCl3 at l
0.00 ppm, and 31P (121 MHz), external 85% H3PO4 at
l 0.00 ppm.
3. Conclusion
Despite the growing interest for chiral fluorous ligands,
only a few examples of chiral fluorous phosphines have
been reported in the literature. We have now devised an
effective approach to the synthesis of fluorous ana-
logues of two versatile ligands such as MOP and
BINAP, combining palladium-catalyzed coupling reac-
tions of easily available binaphthyl building-blocks with
the introduction of fluorous ponytails onto aromatic
compounds via ether bond formation.
The following compounds were prepared according to
literature procedures: (R)-1,1%-bis(2-naphthol)bis(tri-
fluoromethanesulfonate) (R)-4,16 and 1H,1H-penta-
decafluorooctyl-1-ol
nonafluorobutanesulfonate
C7F15CH2OSO2C4F9.14
4.2. Bis(4-methoxyphenyl)phosphine oxide, 3
The new phosphines (R)-1 and (R)-2 have been tested
as ligands in selected metal-catalyzed asymmetric trans-
formations and the most promising results have been
obtained in the case of the allylic alkylation of 1,3-
diphenyl-2-propenyl acetate ( )-14 with several nucleo-
philes catalyzed by [Pd(C3H5)Cl]2 in the presence of the
MOP analogue (R)-1. This ligand proved to be superior
to other previously reported chiral phosphines bearing
fluorous ponytails in the 6,6%-positions of the binaph-
thyl scaffold,12b showing both higher enantioselectivity
and catalytic activity. Good results were also obtained
in the asymmetric Heck reaction between 2,3-dihydro-
furan and aryl triflates catalyzed by Pd(OAc)2/(R)-2,
but preliminary attempts at using this fluorous BINAP
analogue as rhodium ligand for the hydrogenation of
a-acetamidocinnamic acid methyl ester and for the
hydroboration/oxidation of styrene were less satisfac-
tory. It appears that in these cases the introduction of
fluorous ponytails has a negative effect on the level of
enantioselection, possibly due to steric effects arising
from mutual interaction of the perfluoroalkyl chains.
Indeed electronic effects cannot be the determining
factor as the interposition of aryl rings and -OCH2-
insulating spacers effectively shields the phosphorous
atoms from the electron withdrawing effect of the
perfluoroalkyl chains.14
A solution of (4-methoxyphenyl)magnesium bromide
was prepared by slow addition (1 h) of 4-bromoanisole
(11 ml, 86 mmol) in THF (30 ml) to a slurry of
magnesium turnings (2.3 g, 95 mmol) in THF (5 ml).
The mixture was stirred 1 h at reflux and then cooled to
rt. The upper liquid layer was transferred into a flame-
dried flask placed in a cooling bath at −15°C. Neat
Cl2PNEt2 (5 ml, 34.4 mmol) was carefully added while
maintaining the solution temperature lower than −10°C
(Caution!). After 5 min, the cooling bath was removed
and the viscous reaction mixture was stirred 1 h before
being cooled again to −10°C. Aqueous 37% HCl (10
ml) was slowly added under stirring (Caution!), the
mixture was warmed up to rt, stirred for 1 h and finally
treated with H2O (50 ml). The mixture was then
extracted with CH2Cl2 (3×50 ml), and the combined
organic phases were dried over Na2SO4. Evaporation of
the solvent under reduced pressure afforded a yellow
crude product that was purified by crystallization from
acetone/Et2O to give compound 3 (6.3 g, 70%). White
solid, physical data in full agreement with those
reported in the literature.24
4.3. (R)-2-[Bis(4-methoxyphenyl)phosphinyl]-2%-[(tri-
fluoromethanesulfonyl)oxy]-1,1%-binaphthyl, (R)-5
To a mixture of bistriflate (R)-4 (550 mg, 1 mmol),
bis(4-methoxyphenyl)phosphine oxide 3 (1.05 g, 4
mmol), Pd(OAc)2 (22 mg, 0.1 mmol), and 1,4-bis-
(diphenylphosphino)butane (43 mg, 0.1 mmol), were
added dry DMSO (5 ml) and (i-Pr)2NEt (0.68 ml, 4
mmol). After being stirred at 120°C for 12 h, the
solution was cooled to rt, and diluted with AcOEt (50
None of the ligands here studied contained enough
fluorine to be used with success in an FB system, but
they did have enough fluorine to separate them quickly
from the product using liquid-liquid extraction with
perfluorocarbons, as already shown in the case of simi-
lar light fluorous catalytic systems.

J. Bayardon et al. / Tetrahedron: Asymmetry 14 (2003) 2215–2224
2221
ml). The organic solution was washed with water (10×
20 ml), and dried over Na2SO4. Evaporation of the
solvent under reduced pressure gave a residue that was
purified by flash chromatography on silica gel using
CH2Cl2/MeOH (98/2) as the eluent, and then a second
flash chromatography using AcOEt as the eluent to give
compound (R)-5 (636 mg, 96%). White solid; mp 80–
6.65 (d, J=8.7 Hz, 1H, Harom.), 6.95 (d, J=8.7 Hz, 1H,
Harom.), 7.00-7.10 (m, 4H, OH, Harom.), 7.16 (bt, J=7.1
Hz, 2H, Harom.), 7.22–7.32 (m, 3H, Harom.), 7.53–7.62
(m, 3H, Harom.), 7.90 (dd, J=11.4, 2.7 Hz, 1H, Harom.),
7.99 (d, J=8.7 Hz, 1H, Harom.), 8.08 (dd, J=8.7, 2.0
Hz, 1H, Harom.); 31P NMR (76 MHz, DMSO-d6): l 28.8
(s).
1
81°C; Rf=0.6 (AcOEt); [h]2D0=+66.2 (c 0.7, CHCl3); H
NMR (300 MHz, CDCl3): l 3.76 (s, 3H, CH3), 3.77 (s,
3H, CH3), 6.66 (dd, J=8.8, 2.3 Hz, 2H, Harom.), 6.76
(dd, J=8.8, 2.3 Hz, 2H, Harom.), 6.99 (d, J=8.5 Hz, 1H,
4.6. (R)-2-{Bis[4-(1H,1H-pentadecafluorooctyloxy)-
phenyl]phosphinyl}-2%-(1H,1H-perfluorooctyloxy)-
1,1%-binaphthyl, (R)-8
Harom.), 7.10 (d, J=8.5 Hz, 1H, Harom.), 7.17 (bt, J=7.2
Hz, 2H, Harom.), 7.25-7.36 (m, 6H, Harom.), 7.42 (bt,
J=7.2 Hz, 1H, Harom.), 7.55 (bt, J=7.2 Hz, 1H, Harom.),
7.71–7.94 (m, 3H, Harom.), 8.00 (dd, J=8.8, 2.3 Hz, 1H,
To a solution of compound (R)-7 (800 mg, 1.6 mmol)
and C7F15CH2OSO2C4F9 (5.46 g, 8 mmol) in DMF
previously warmed at 100°C was added Cs2CO3 (2.08 g,
6.4 mmol). The mixture was stirred at 100°C for 8 h.
The solution was cooled at rt, poured into water (50
ml), and extracted with Et2O (3×10 ml), and with
CH2Cl2 (3×10 ml). The combined organic phases were
dried over Na2SO4. Evaporation of the organic solvents
gave a residue that was purified by flash chromatogra-
phy on silica using petroleum ether/Et2O (4:1) as the
eluent to give fluorous compound (R)-8 (1.85 g, 70%).
Yellow solid; mp 64–66°C; Rf=0.5 (petroleum ether/
H
arom.); 31P NMR (76 MHz, CDCl3): l 28.6 (s); 19F
NMR (122 MHz, CDCl3): l −75.4 (s). Anal. calcd for
C35H26F3O6PS (662.62): C, 63.44; H, 3.96; found: C,
63.01; H, 3.84.
4.4. (R)-2-[Bis(4-hydroxyphenyl)phosphinyl]-2%-[(tri-
fluoromethanesulfonyl)oxy]-1,1%-binaphthyl, (R)-6
Triflate (R)-5 (1.8 g, 2.72 mmol) was dissolved in dry
CH2Cl2 (40 ml) and the solution was cooled to 0°C. A
1 M solution of BBr3 in CH2Cl2 (16.3 ml, 16.3 mmol)
was added dropwise in 5 min, and the solution was
stirred at 0°C for 2 h. After warming up the solution to
5°C, water (15 ml) was slowly added. The organic layer
was separated, diluted with AcOEt (15 ml), and washed
several times with H2O (4×10 ml). After removal of the
organic solvent, the residue was recrystallized from
Et2O to give compound (R)-6 (1.7 g, 99%). White solid;
mp 176–180°C; Rf=0.4 (CH2Cl2/CH3OH 98:2); 1H
NMR (300 MHz, CDCl3): l 6.49 (dd, J=11.0, 2.4 Hz,
2H, Harom.), 6.55 (dd, J=11.0, 2.4 Hz, 2H, Harom.), 6.85
(d, J=8.5 Hz, 1H, Harom.), 6.98–7.10 (m, 6H, Harom.),
7.19–7.25 (m, 2H, Harom.), 7.32 (bt, J=7.6 Hz, 1H,
1
Et2O 4:1); [h]2D0=+60.0 (c 0.3, CHCl3); H NMR (300
MHz, CDCl3): l 4.24–4.59 (m, 6H, CH2), 6.56 (dd,
J=8.8, 2.1 Hz, 2H, Harom.), 6.74 (dd, J=8.8, 2.1 Hz,
2H, Harom.), 6.79 (d, J=8.5 Hz, 1H, Harom.), 7.00–7.28
(m, 7H, Harom.), 7.38 (dd, J=11.4, 8.7 Hz, 2H, Harom.),
7.52 (bt, J=7.4 Hz, 1H, Harom.), 7.63 (d, J=8.1 Hz, 1H,
Harom.), 7.76 (dd, J=9.0, 5.0 Hz, 1H, Harom.), 7.81 (d,
J=8.1 Hz, 1H, Harom.), 7.91 (d, J=8.1 Hz, 1H, Harom.),
7.98 (dd, J=8.8, 2.1 Hz, 1H, Harom.); 31P NMR (76
MHz, CDCl3): l 28.8 (s); 19F NMR (122 MHz, CDCl3):
l −126.5, −123.8, −123.5, −123.1, −122.6, −122.3, −
120.0, −119.7, −81.3, −81.2. Anal. calcd for
C56H26F45O4P (1648.70): C, 40.80; H, 1.59; found: C,
40.47; H, 1.64.
H
arom.), 7.48 (bt, J=7.6 Hz, 1H, Harom.), 7.61 (dd,
J=11.6, 8.5 Hz, 1H, Harom.), 7.72 (d, J=8.2 Hz, 1H,
arom.), 7.82 (d, J=8.2 Hz, 1H, Harom.), 7.89 (d, J=8.2
H
Hz, 1H, Harom.), 7.96 (dd, J=8.5, 2.4 Hz, 1H, Harom.);
4.6.1.
(R)-2-{Bis[4-(1H,1H-pentadecafluorooctyloxy)-
31P NMR (76 MHz, CDCl3): l 33.2 (s); 19F NMR (122
phenyl]-phosphino}-2%-(1H,1H-pentadecafluorooctyl-oxy)-
1,1%-binaphthyl, (R)-1. To an ice-cooled suspension of
perfluorous phosphine oxide (R)-8 (1.21 g, 0.73 mmol)
in deareated toluene (15 ml) was added HSiCl3 (0.37
ml, 3.67 mmol). The reaction was warmed to 110°C for
3 h under stirring. The solution was cooled to 0°C,
diluted with deareated Et2O (10 ml), and neutralized
with a saturated aqueous solution of NaHCO3 (15 ml).
The suspension was filtered under nitrogen on a Celite
plug that was washed with Et2O (3×15 ml). The organic
phase was dried over Na2SO4. Evaporation of the sol-
vent under reduced pressure gave phosphine (R)-1 (1.08
g, 91%). White solid; mp 48–49°C; Rf=0.7 (petroleum
MHz, CDCl3):
l
−75.7 (s). Anal. calcd for
C33H22F3O6PS (634.57): C, 62.46; H, 3.49; found: C,
62.93; H, 3.69.
4.5. (R)-2-[Bis(4-hydroxyphenyl)phosphinyl]-2%-hydroxy-
1,1%-binaphthyl, (R)-7
Compound (R)-6 (1.63 g, 2.57 mmol) was dissolved in
a mixture of dioxane/MeOH 2:1 (13 ml). Aqueous
NaOH 3 M (10 ml) was added and the mixture was
vigorously stirred for 24 h at rt. The pH of the solution
was brought to 1 by addition of HCl 36% and the
mixture was extracted with AcOEt (3×20 ml). The
organic phase was dried over Na2SO4, and the solvent
was evaporated under reduced pressure to give com-
pound (R)-7 as a grayish solid (1.19 g, 92%) that was
directly used for the next step without further purifica-
1
ether/Et2O 4:1); [h]2D0=+23.1 (c 0.3, CHCl3); H NMR
(300 MHz, CDCl3): l 4.16 (dt, J=24.6, 12.6 Hz, 2H,
CH2), 4.48 (dt, J=13.1 Hz, 4H, CH2), 6.72 (d, J=8.4
Hz, 2H, Harom.), 6.86–6.92 (m, 3H, Harom.), 7.03 (dd,
J=8.5, 7.1 Hz, 2H, Harom.), 7.06–7.12 (m, 1H, Harom.),
7.17–7.35 (m, 6H, Harom.), 7.41 (dd, J=8.5, 3.0 Hz, 1H,
Harom.), 7.44–7.50 (m, 1H, Harom.), 7.86–7.91 (m, 3H,
Harom.), 8.01 (d, J=9.1 Hz, 1H, Harom.); 31P NMR (76
1
tion. Mp 229–230°C; [h]2D0=+124.3 (c 0.5, MeOH); H
NMR (300 MHz, DMSO-d6): l 6.41 (dd, J=8.7, 2.4
Hz, 2H, Harom.), 6.61 (dd, J=8.7, 2.4 Hz, 2H, Harom.),

2222
J. Bayardon et al. / Tetrahedron: Asymmetry 14 (2003) 2215–2224
MHz, CDCl3):
C56H26F45O3P (1632.70): C, 41.17; H, 1.61; found: C,
40.56; H, 1.53.
l
−15.5 (s). Anal. calcd for
4.9. (R)-2,2%-[Bis(4-methoxyphenyl)phosphinyl]-1,1%-
binaphthyl, (R)-11
To a solution of compound 10 (1.2 g, 1.58 mmol) in
acetone (10 ml) was added at rt H2O2 10% (0.81 ml).
The mixture was stirred at rt for 8 h, then poured into
water (10 ml), and extracted with CH2Cl2 (3×20 ml).
The combined organic phases were dried over Na2SO4,
and the solvent removed under reduced pressure to
afford racemic compound 11 as a yellowish solid (1.18
mg, 96%). A solution of racemic compound 11 (1.18 g,
1.52 mmol), (2R,3R)-2,3-di-O,O-benzoyltartaric acid
(0.572 g, 1.52 mmol), and toluene (0.14 g, 1.52 mmol),
in CHCl3 (5 ml) was heated at reflux until a homoge-
neous solution was obtained. Ethyl acetate (16 ml) was
added dropwise at the refluxing temperature, and the
mixture was allowed to stand at rt overnight to give a
complex 1:1 of (R)-11 and (2R,3R)-2,3-di-O,O-benzoyl-
tartaric acid with [h]D20=−34.2 (c 0.5, CHCl3). No essen-
tial change in optical rotation was observed after
4.7. 2-[Bis(4-methoxyphenyl)phosphino]-2%-[(trifluoro-
methanesulfonyl)oxy]-1,1%-binaphthyl, 9
To a solution of racemic 2-[bis(4-methoxyphenyl)-
phosphinyl] - 2% - [(trifluoromethanesulfonyl)oxy] - 1,1%-
binaphthyl 5 (3.54 g, 5.21 mmol) in deareated toluene
(80 ml) cooled to 0°C was added HSiCl3 (2.63 ml, 26.1
mmol). After being stirred for 8 h at 110°C, the solu-
tion was cooled to 0°C, neutralized with an aqueous
solution of NaOH 30% (30 ml). The mixture was
warmed to 40°C until two clear solutions were
obtained. The organic layer was separated and the
aqueous phase was extracted with CH2Cl2 (2×10 ml),
and diethyl ether (2×10 ml). The combined organic
layers were dried over Na2SO4, and evaporated under
reduced pressure. The obtained residue was purified by
column chromatography on silica gel (eluent petroleum
ether/diethyl ether 1:1) to give phosphine 9 (2.5 g, 74%).
White solid; mp 76–78°C; Rf=0.5 (petroleum ether/
1
further recrystallization. H NMR (300 MHz, CDCl3):
l 3.74 (s, 6H, CH3), 3.72 (s, 6H, CH3), 5.76 (s, 2H,
CHO), 6.58–6.64 (m, 8H, Harom.), 6.82 (d, J=8.5 Hz,
2H, Harom.), 6.93 (bt, J=7.0 Hz, 2H, Harom.), 7.12 (dd,
J=11.4, 8.6 Hz, 4H, Harom.), 7.23–7.41 (m, 12H,
Harom.), 7.49 (bt, J=7.4 Hz, 2H, Harom.), 7.68–7.72 (m,
4H, Harom.), 8.00 (d, J=7.4 Hz, 4H, Harom.). This solid
was dissolved in CHCl3 (10 ml), and washed with a 1N
NaOH solution (5×5 ml). Evaporation of the solvent
gave (R)-11 (433 mg, 74%) White solid; mp 150–152°C;
[h]2D0=+107.6 (c 0.4, CHCl3); 1H NMR (300 MHz,
CDCl3): l 3.74 (s, 6H, CH3), 3.78 (s, 6H, CH3), 6.60
(dd, J=8.7, 2.1 Hz, 4H, Harom.), 6.73 (d, J=8.3 Hz, 2H,
Harom.), 6.87 (dd, J=8.7, 2.1 Hz, 4H, Harom.), 6.93 (m,
2H, Harom.), 7.19 (dd, J=8.6, 6.4 Hz, 4H, Harom.), 7.39
(m, 2H, Harom.), 7.42 (dd, J=11.4, 8.6 Hz, 2H, Harom.),
7.65 (dd, J=8.6, 6;4 Hz, 4H, Harom.), 7.69 (d, J=8.1
Hz, 2H, Harom.), 7.87 (dd, J=8.6, 2.1 Hz, 2H, Harom.);
31P NMR (76 MHz, CDCl3): l 28.7 (s). Anal. calcd for
C48H40O6P2 (774.80): C, 74.41; H, 5.20; found: C, 74.58;
H, 5.17.
1
Et2O 1:1); H NMR (300 MHz, CDCl3): l 3.72 (s, 3H,
CH3), 3.80 (s, 3H, CH3), 6.63 (d, J=8.3 Hz, 2H,
Harom.), 6.84–6.94 (m, 5H, Harom.), 7.08 (bt, J=7.1 Hz,
1H, Harom.), 7.12–7.21 (m, 3H, Harom.), 7.27 (m, 1H,
Harom.), 7.41 (d, J=8.3 Hz, 1H, Harom.), 7.40–7.52 (m,
2H, Harom.), 7.52 (d, J=9.0 Hz, 1H, Harom.), 7.87–7.94
(m, 3H, Harom.), 8.00 (d, J=9.0 Hz, 1H, Harom.); 31P
NMR (76 MHz, CDCl3): l −15.3 (s). Anal. calcd for
C35H26F3O5PS (646.62): C, 65.01; H, 4.05; found: C,
65.13; H, 4.35.
4.8. 2-[Bis(4-methoxyphenyl)phosphino]-2%-[bis(4-
methoxyphenyl)phosphinyl]-1,1%-binaphthyl, 10
A mixture of compound 9 (2.5 g, 3.85 mmol), bis(4-
methoxyphenyl)phosphine oxide 3 (3.03, 11.6 mmol),
palladium acetate (86 mg, 0.385 mmol), 1,4-bis-
(diphenylphosphino)butane (164 mg, 0.385 mmol),
diisopropylethylamine (2 ml, 11.6 mmol), in dry DMSO
(30 ml), was stirred at 120°C for 24 h. The solution was
cooled to rt, diluted with ethyl acetate (80 ml), and
washed with water (10×10 ml). The solvent was evapo-
rated under reduced pressure to give a dark green
residue that was purified by flash column chromatogra-
phy on silica using ethyl acetate as the eluent to afford
compound 10 (1.2 g, 41%). Pale yellow solid; mp 128–
4.10. (R)-2,2%-[Bis(4-hydroxyphenyl)phosphinyl]-1,1%-
binaphthyl, (R)-12
A solution of phosphine oxide (R)-11 (433 mg, 0.56
mmol) in dry CH2Cl2 (20 ml) was cooled at 0°C. A 1 M
solution of BBr3 in CH2Cl2 (5.6 ml, 5.6 mmol) was
added, and the reaction mixture was stirred at 0°C for
1 h, and then at rt for 24 h. The solution was cooled to
5°C and CH3OH (10 ml) was carefully added. After
removal of the organic solvents, the residue was recrys-
tallized from hot CH3OH (10 ml) by adding cold water
(5 ml) to give hydroxyphosphine oxide (R)-12 (380 mg,
95%). White solid; mp >220°C; [h]2D0=+15.0 (c 0.5,
1
130°C; Rf=0.7 (AcOEt); H NMR (300 MHz, CDCl3):
l 3.71 (s, 6H, CH3), 3.75 (s, 6H, CH3), 6.54–6.59 (m,
5H, Harom.), 6.64 (dd, J=8.8, 2.2 Hz, 2H, Harom.),
6.72–6.88 (m, 6H, Harom.), 6.97 (bt, J=7.0 Hz, 1H,
1
CH3OH); H NMR (300 MHz, DMSO-d6): l 6.55 (d,
J=8.6 Hz, 2H, Harom.), 6.65–6.69 (m, 6H, Harom.), 6.82
(bt, J=7.5 Hz, 2H, Harom.), 7.13 (dd, J=11.5, 8.6 Hz,
4H, Harom.), 7.31 (dd, J=11.5, 8.6 Hz, 2H, Harom.), 7.38
(bt, J=7.5 Hz, 2H, Harom.), 7.44 (dd, J=11.5, 8.6 Hz,
2H, Harom.), 7.86–7.92 (m, 4H, Harom.), 9.95 (s, 4H,
OH); 31P NMR (76 MHz, DMSO-d6): l 28.2 (s). Anal.
calcd for C44H32O6P2 (718.69): C, 73.53; H, 4.49; found:
C, 73.11; H, 4.40.
Harom.), 7.18 (dd, J=8.8, 6.4 Hz, 2H, Harom.), 7.28–7.37
(m, 5H, Harom.), 7.43 (dd, J=8.6, 11.0 Hz, 2H, Harom.),
7.65–7.73 (m, 3H, Harom.), 7.81 (d, J=8.1 Hz, 1H,
Harom.), 7.92 (dd, J=8.6, 2.3 Hz, 1H, Harom.); 31P NMR
(76 MHz, CDCl3): l –17.7 (s), 27.7 (s). Anal. calcd for
C48H40O5P2 (758.80): C, 75.98; H, 5.31; found: C, 76.05;
H, 5.49.

J. Bayardon et al. / Tetrahedron: Asymmetry 14 (2003) 2215–2224
2223
4.11. (R)-2,2%-[Bis(4-(1H,1H-pentadecafluorooctyloxy)
phenyl)phosphinyl]-1,1%-binaphthyl, (R)-13
ml). After stirring the mixture for 1 h at the desired
temperature, a solution of racemic 1,3-diphenylprop-2-
enyl acetate (14) (150 mg, 0.6 mmol) in the solvent (2
ml) was added. After 30 min, this solution was trans-
ferred to a Schlenk tube containing the nucleophile (1.2
mmol), N,O-bis-(trimethylsilyl)acetamid (244 mg, 1.2
mmol), and KOAc (5.9 mg, 60 mmol) in 4 ml of solvent.
The reaction mixture was stirred at the desired temper-
ature for the indicated time. After the indicated time, a
1 M solution of NaOH (8 ml) was added, and the
product was extracted with AcOEt (10 ml). Evapora-
tion of the solvent gave a residue; the conversion and
enantiomeric excess were determined by HPLC analysis
(column Chirapalk AD 0.46×25 cm).
To a suspension of compound (R)-12 (380 mg, 0.53
mmol) and C7F15CH2OSO2C4F9 (3.68 g, 5.4 mmol) in
DMF (20 ml) warmed to 120°C was added Cs2CO3
(1.76 g, 5.4 mmol). The mixture was warmed at this
temperature for 24 h, and then cooled to 0°C. A 10%
aqueous HCl (20 ml) was carefully added, and the
mixture was diluted with diethyl ether (40 ml), and
washed several times with 10% HCl (2×20 ml), and
water (10×10 ml). The aqueous phase was extracted one
time with CFCl2CClF2 (10 ml). The combined organic
and fluorous layers were dried over Na2SO4, and the
solvents removed under reduced pressure to give a
brown residue that was purified by column chromatog-
raphy on silica (eluent CH2Cl2/AcOEt 1:1) to afford
compound (R)-13 (520 mg, 42%). Yellow solid; mp
128–130°C; Rf=0.5 (CH2Cl2/AcOEt 1:1); [h]2D0=+47.2
4.14. Standard Heck reaction
In a Schlenk tube, Pd(OAc)2 (4.1 mg, 18.4 mmol) and
ligand (R)-2 (92.4 mg, 41.7 mmol) were dissolved in
trifluorotoluene (2 ml). After stirring for 15 min at
25°C, the solution was transferred to a Schlenk tube
containing the aryl triflate (0.6 mmol). After stirring at
25°C for 10 min, dihydrofuran (215 mg, 7.0 mmol), and
diisopropylethylamine (238 mg, 1.84 mmol) were
added. The solution was stirred at 40°C for the indi-
cated time. The solution was then cooled and diluted
with diethyl ether (5 ml). The organic phase was sepa-
rated and washed with a saturated aqueous solution of
NaCl (5 ml), and water (5 ml). Evaporation of the
solvent gave a residue that was purified by column
chromatography on silica. The conversion was deter-
mined by GC using Quadrex OV1 (30 m×0.25 mm) as
the column, and the e.e. was determined by GC using
Cydex B (25 m×0.25 mm) for Ar=C6H5 and 4-Cl-
C6H4, or HPLC using Chiralpak AD (25 cm×4.6 mm,
hexane/i-PrOH 92.5/17.5 as the solvent) for Ar=
naphthyl.
1
(c 0.7, CFCl2CClF2); H NMR (300 MHz, acetone-d6):
l 4.85 (bq, J=12.9 Hz, 8H, CH2), 6.69 (d, J=8.3 Hz,
2H, Harom.), 6.89 (t, J=7.4 Hz, 2H, Harom.), 7.03–7.05
(m, 8H, Harom.), 7.39–7.50 (m, 8H, Harom.), 7.79 (dd,
J=11.5, 8.8 Hz, 4H, Harom.), 7.91–7.96 (m, 4H, Harom.);
31P NMR (76 MHz, d6-acetone): l 27.8 (s); 19F NMR
(122 MHz, acetone-d6): l −126.6, −123.5, −123.2, −
122.4, −119.9, −119.7, −81.2 (t, J=4.2 Hz). Anal. calcd
for C76H36F60O6P2 (2246.98): C, 40.60; H, 1.61; found:
C, 40.41; H, 1.52.
4.12. (R)-2,2%-[Bis(4-(1H,1H-pentadecafluorooctyloxy)
phenyl)phosphino]-1,1%-binaphthyl, (R)-2
A mixture of phosphine oxide (R)-13 (500 mg, 0.22
mmol), Et3N (0.21 ml, 1.54 mmol), HSiCl3 (0.11 ml,
1.11 mmol), in dry xylene (5 ml) was warmed at 125°C
for 48 h under vigorous stirring. The solution was
cooled at rt, and a 30% aqueous solution of NaOH (10
ml) was added carefully. The mixture was stirred at
60°C until the organic and aqueous layers became clear.
CH2Cl2 (20 ml) was added, and the organic phase was
separated. The aqueous phase was washed with
CFCl2CClF2 (10 ml) and the organic and fluorous
phases were dried over Na2SO4. Evaporation of the
solvents under reduced pressure gave a residue that was
purified by column chromatography on silica gel (elu-
ent petroleum ether/CH2Cl2 4:1) to afford phosphine
(R)-2 (233 mg, 48%). White solid; mp 49–50°C; Rf=0.4
(petroleum ether/CH2Cl2 4:1), [h]2D0=+27.6 (c 0.4,
Acknowledgements
This work was supported by a fellowship from the
French Ministry of Education (D.M. and J.B.) and by
the joint research project CNR/CNRS 2002-2003
‘Organometallic catalysis in biphasic fluorous system’.
References
1
CHCl3); H NMR (300 MHz, CDCl3): l 4.36 (m, 8H,
CH2), 6.69 (bd, J=8.4 Hz, 8H, Harom.), 6.81 (d, J=8.4
Hz, 1H, Harom.), 6.94–7.01 (m, 5H, Harom.), 7.37 (m, 2H,
Harom.), 7.86 (dd, J=12.4, 8.5 Hz, 4H, Harom.); 31P
NMR (76 MHz, CDCl3): l −17.3 (s); 19F NMR (122
MHz, CDCl3): l −126.6, −123.5, −123.2, −122.4, −
120.0, −119.8, −81.2 (t, J=4.1 Hz). Anal. calcd for
C76H36F60O4P2 (2214.98): C, 41.21; H, 1.64; found: C,
41.19; H, 1.72.
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