Phosphorus(III) ligands with fluorous ponytails

Article abstract of DOI:10.1039/a704872f

A series of phosphorus(III) compounds incorporating one or more C₆F₁₃ 'ponytails' have been prepared as a pool of ligands for coordination and catalytic studies under the fluorous biphase regime. Solubility studies indicate that only ligands with three or more ponytails are preferentially soluble in perfluorocarbon solvents.

Full text of DOI:10.1039/a704872f

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Phosphorus(III) ligands with fluorous ponytails
Pravat Bhattacharyya, David Gudmunsen, Eric G. Hope,* Ray D. W. Kemmitt,
Danny R. Paige and Alison M. Stuart
Department of Chemistry, University of Leicester, Leicester, UK LE1 7RH
A series of phosphorus(III) compounds incorporating one or more C6F13 ‘ponytails’ have been prepared as
a pool of ligands for coordination and catalytic studies under the fluorous biphase regime. Solubility
studies indicate that only ligands with three or more ponytails are preferentially soluble in perfluorocarbon
solvents.
i, ii
Introduction
ICH2CH2C6F13
PPh3–x(CH2CH2C6F13)x
The commercial exploitation of perfluorinated solvents relies
upon their unusual physical and chemical properties such as low
miscibilities with common organic solvents, high solubility for
gases, particularly oxygen, and low reactivity.1 A novel appli-
cation of these properties to the catalyst–product separation
problems inherent in homogeneous catalysis has recently been
described.2 In this ‘fluorous biphasic (FBS) approach’, the cata-
lyst is anchored in the fluorocarbon phase using long perfluori-
nated side-chains, called ‘fluorous ponytails’, whereas the sub-
strate(s) and product(s) are dissolved in another solvent (typic-
ally an organic solvent). At elevated temperatures the system is
homogeneous allowing catalysis to occur, and on cooling the
system separates completely allowing the facile separation of
the catalyst for recycling. Although the derivatisation of ‘estab-
lished’ catalysts with ponytails would appear to offer a straight-
forward way to exploit this procedure, there have been only a
few subsequent applications of this approach in synthetic
organic chemistry as a ‘fluorous label’ for facile substrate–
product separation3 and catalytically in the epoxidation of
alkenes.4 We have a long-standing interest in the synthesis and
application of fluorinated organophosphorus ligands5 and here
describe general routes to the preparation of a series of phos-
phorus() ligands containing long perfluorinated groups.
1 x = 1
2 x = 2
3 x = 3
iii
HOCH2CH2C6F13
PPh3–x(OCH2CH2C6F13)x
4 x = 1
5 x = 2
6 x = 3
Br
Br
iv
v, ii
Ph3–x
P
C6F13
x
I
C6F13
7
8 x = 1
9 x = 2
10 x = 3
v, vi
F13
C
P
P
11
C6F13
2
2
OH
OH
iv
iii
Ph3–x
P
O
C6F13
Results and discussion
x
Scheme 1 illustrates the synthetic rationale for the C6F13 pony-
tail; analogous chemistry with longer and shorter chain lengths
has also been achieved. Only 3 has been reported (incompletely)
previously2 and this new synthetic route, via the Grignard
reagent, is significantly easier than the route reported previ-
ously as it does not require the handling of phosphine (PH3).
Additionally, this route is readily extended to ligands with one
or two ponytails (1 and 2) offering a general route to a wider
range of fluorous derivatised phosphorus() ligands. We note
that an alternative synthesis of adducts of 1 and 3 has also been
reported recently.6 The direct reaction of the commercially
available 1H,1H,2H,2H-perfluoro alcohols† with phosphorus
chlorides in the presence of base yields a series of related phos-
phinite 4, phosphonite 5 and phosphite 6 ligands. For all of
these ligands, the C2H4 unit has been incorporated to act as a
spacer group between the fluorous ponytail and the phosphorus
atom in an attempt to minimise the strong electron withdrawing
I
C6F13
12
13 x = 1
14 x = 2
15 x = 3
Scheme 1 Reagents and conditions: i, Mg, Et2O; ii, PPh3 Ϫ xClx, Et2O;
iii, PPh3 Ϫ xClx, NEt3, Et2O; iv, C6F13I, Cu, 2,2Ј-bipyridine (bipy),
DMSO, C6F6; v, BunLi, Et2O; vi, Cl2PCH2CH2PCl2, Et2O.
effect of the fluorous tail. The success of this approach can be
measured by a comparison of the 31P chemical shifts for these
ligands with the analogous molecules with a proton instead of
the C6F13 unit (Table 1). For 1–3 the introduction of the C6F13
unit causes a small low frequency shift in δP whereas in 4–6, the
introduction of the same number of ponytails causes a similar
magnitude, but high frequency, shift indicating modest success
in buffering the influence of the fluorous tails. Ligands 8–11
and 13–15 contain the alternative C6H4 spacer group. The
selective copper-mediated coupling reaction of C6F13I with 4-
bromoiodobenzene gives the intermediate 7 in 80% yield.7 The
principal impurity, 1,4-bis(perfluorohexyl)benzene, is readily
removed by distillation of the product. Similarly, we find, after
appropriate work-up, a 63% yield of the 4-(perfluorohexyl)-
phenol 12 from the coupling of C6F13I and 4-iodophenol; a
similar coupling reaction using iodoperfluoro ethers has been
† For the purposes of clarity the nomenclature system used for com-
pounds of this type shows the positions of the hydrogen atoms preceed-
ing the name [e.g. 1 (1H,1H,2H,2H-perfluorooctyl)diphenylphosphine].
The IUPAC system, which has not been used, shows the positions of
the fluorine substituents [e.g. 1 (3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-
octyl)diphenylphosphine].
J. Chem. Soc., Perkin Trans. 1, 1997
3609

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Table 1 31P NMR Spectral data for fluorous derivatised ligandsa
C6H4Rf-4b
OC6H5
OC6H4Rf-4b
c
b
c
b
d
Ligand
C2H5
C2H4Rf
OC2H5
OC2H4Rf
C6H5
PPh2R
PPhR2
PR3
Ϫ12.0
Ϫ16.0
Ϫ20.4
Ϫ16.0
Ϫ23.0
Ϫ25.0
109.8
153.5
137.1
116.5
156.7
139.4
Ϫ5.0
Ϫ5.0
Ϫ5.0
Ϫ5.0
Ϫ5.4
Ϫ6.0
111.1
158.5
128.2
112.6
159.1
125.0
R2P(CH2)PR2
Ϫ12.3
Ϫ12.8
a Chemical shifts in ppm. b Rf = C6F13. c Handbook of P-31 NMR Data, CRC Press, Florida, 1991. d M. J. Atherton, J. Fawcett, A. P. Hill, J. H.
Holloway, E. G. Hope, D. R. Russell, G. C. Saunders and R. M. J. Stead, J. Chem. Soc., Dalton Trans., 1997, 1137.
Experimental
CαF2 CβF2 CγF2 CδF2 CεF2 CF3
The H, 19F and 31P NMR spectra were recorded on a Bruker
ARX 250 spectrometer at 250.13, 235.34 and 101.26 MHz
respectively in CDCl3 unless stated otherwise: all chemical
shifts are quoted in ppm using the high frequency positive con-
1
Fig. 1 Atom labelling for fluorous ponytails
described.8 We were unable to form a Grignard from the inter-
mediate 7 but, after treatment with BunLi at low temperature,
the addition of the corresponding phosphorus chlorides gave
8–11 in high yields. The reaction of the derivatised phenol 12
with the same phosphorus chlorides in the presence of base
gave, after work-up, the phosphinite 13, phosphonite 14 and
phosphite 15. As for the alkyl-substituted ligands above, a
comparison of the 31P NMR chemical shifts for these aryl-
substituted ligands (Table 1) with those for the parent ligands
indicates that the aryl spacers are more effective at reducing
the electronic influence of the fluorous ponytails, suggesting
that these ligands may have a more extensive coordination
chemistry.
The phosphite 6, is extremely sensitive to hydrolysis, forming
P(ORf)2(O)(H) (δP 7.6, 1JHP 720 Hz), the alkyl-phosphinite and
-phosphonite show some hydrolytic sensitivity but 13–15 are air-
and moisture-stable. The tris-, bis- and mono-arylphosphines
show increasing air-sensitivity and the trialkylphosphine 3
undergoes rapid aerial oxidation to OP(C2H4C6F13)3 (δP 42.6).
The solubility of the ligands in perfluorinated solvents increases
with the number of ponytails; i.e. 1, 4, 8 and 13 are slightly
soluble in perfluoro-1,3-dimethylcyclohexane whilst 3, 6, 10, 11
and 15 are preferentially soluble in this solvent at room
temperature.
1
vention; H NMR spectra were referenced internally or exter-
nally to tetramethylsilane, 19F NMR spectra were referenced
externally to CFCl3 and 31P NMR spectra were referenced
externally to 85% H3PO4. Abbreviations for NMR spectral
multiplicities are as follows: br = broad, s = singlet, d = doublet,
t = triplet, tt = triplet of triplets, dd = doublet of doublets,
vt = virtual triplet, vq = virtual quartet, tm = triplet of multi-
plets, um = unresolved multiplet. Elemental analyses were per-
formed by Butterworth Laboratories Ltd and mass spectra
(electron impact and fast atom bombardment in positive mode
using 3-nitrobenzyl alcohol matrix) were recorded on a Kratos
Concept 1H mass spectrometer.
1H,1H,2H,2H-perfluorooctyl iodide,† perfluorohexyl iodide
and 1H,1H,2H,2H-perfluorooctanol (Fluorochem Ltd.) were
distilled before use. Diethyl ether was refluxed over sodium
metal before use. Triethylamine was dried by distillation from,
and stored over, CaH2. Hexafluorobenzene, perfluoro-1,3-
dimethylcyclohexane (F2 Chemicals Ltd.), DMSO, 4-bromo-
iodobenzene, 4-iodophenol, phosphorus trichloride, phenyl-
dichlorophosphine, diphenylchlorophosphine and tetrachloro-
1,2-diphosphinoethane were used as supplied.
The compounds have been characterised by a combination of
analytical and spectroscopic techniques. All the compounds
show either parent ions [Mϩ] or [M ϩ O]ϩ in their mass spectra
and fragmentation patterns dominated by loss of fluoride ion,
CF3, C2F5 and related fluoroalkyl groups. In the 1H NMR spec-
tra of 4 and 6, the chemical shifts of the methylene protons and
the 3JHH and 3JHF coupling constants are essentially identical to
the values for C6F13C2H4OH. Owing to the similar magnitudes
Preparation of phosphorus(III) compounds†
(1H,1H,2H,2H-Perfluorooctyl)diphenylphosphine 1. A solu-
tion of CF3(CF2)5C2H4I (23.7 g, 0.05 mmol) in diethyl ether (70
cm3) was added dropwise to magnesium turnings (1.44 g, 0.06
mol) suspended in diethyl ether (15 cm3) with two drops of 1,2-
dibromoethane. The mixture was refluxed for 2 h, and the solu-
tion decanted into a second flask under nitrogen. Diphenyl-
chlorophosphine (11.03 g, 0.05 mol) in diethyl ether (75 cm3)
was added dropwise to the solution over 2 h, and the mixture
was hydrolysed with degassed aqueous ammonium chloride.
The organic layer was separated, dried over MgSO4 and the
solvent removed in vacuo. The resulting brown solid was dis-
solved in the minimum amount of diethyl ether, passed quickly
through an alumina column eluting with light petroleum (bp
40–60 ЊC), the solvent removed in vacuo and the white solid
heated (60 ЊC) under dynamic vacuum (0.01 mmHg) for 2 h to
remove all traces of fluorinated starting material to leave the
product as a white solid, mp 42–44 ЊC (13.3 g, 50%) (Found: C,
43.0; H, 2.4; F, 48.8. C20H14F13P requires C, 45.1; H, 2.6;
F, 46.4%); m/z (EI) 532 (Mϩ, 100%), 513 (17) and 185 (60); δH
7.0–7.7 (10H, um, C6H5), 2.3 (2H, br t, 3JHH 10, PCH2), 2.1 (2H,
3
3
of the JHH and JPH couplings, the OCH2 resonances in both
compounds appear as virtual quartets. For 5, the OCH2 and
CH2CF2 moieties are complicated second-order multiplets. For
4
4, 5 and 6 there is no resolvable JHP coupling between the
CH2CF2 protons and the phosphorus nucleus. Likewise, for 10,
3
3
the similar magnitude of the JHH and JHP are responsible for
the virtual triplet appearance of the ortho-protons. The virtual
triplet appearance for the methylene protons in 11 is similar to
that for ethylenebis(diphenylphosphine) (dppe).9 The 19F NMR
spectra of 1–15 are uninformative and remarkably similar; six,
highly consistent, multiplet resonances. The highest frequency
resonances are assigned to the terminal CF3 group. The remain-
ing, CF2, resonances are assigned according to Fig. 1 from 19F–
19F COSY experiments.
3
um, CH2CF2); δF Ϫ81.3 (3F, t, JFF 14, CF3), Ϫ115.0 (2F, um,
This work clearly indicates that a range of phosphorus()
compounds which are potential ligands for coordination chem-
istry can be prepared. However, in view of the requirement that
three or more ponytails are necessary to confer preferential
perfluorocarbon solubility, it is likely that only complexes of
these highly derivatised ligands are likely to be useful for cata-
lysis in the FBS. For example, the rhodium–carbonyl chloride
complexes of the tris-derivatised ligands 3 and 10 are highly
fluorous phase soluble.10 Further results of our coordination
and catalytic studies will be published elsewhere.
CαF2), Ϫ123.0 (2F, um, CβF2), Ϫ123.4 (2F, um, CδF2), Ϫ123.6
(2F, um, CεF2), Ϫ126.6 (2F, um, CγF2).
Bis(1H,1H,2H,2H-perfluorooctyl)phenylphosphine 2. This was
prepared similarly using phenyldichlorophosphine (5.513 g,
0.025 mol) affording the product as a white solid, mp 35–37 ЊC
(10 g, 50%) (Found: C, 32.9; H, 1.5; F, 58.4. C22H13F26P requires
C, 32.9; H, 1.6; F, 58.7%); m/z (EI) 802 (Mϩ, 75%), 783 (29),
733 (5) and 683 (4); δH 6.9–7.7 (5H, um, C6H5), 2.3 (4H, br
3
t, JHH 10, PCH2), 2.1 (4H, um, CH2CF2); δF Ϫ81.4 (3F, t,
3JFF 12, CF3), Ϫ114.9 (2F, um, CαF2), Ϫ122.4 (2F, um, CβF2),
3610
J. Chem. Soc., Perkin Trans. 1, 1997

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Ϫ123.4 (2F, um, CδF2), Ϫ123.7 (2F, um, CεF2), Ϫ126.6 (2F, um,
CγF2).
fluorohexyl)bromobenzene (6.57 g, 0.014 mol) in diethyl ether
(75 cm3) at Ϫ78 ЊC and then stirred at this temperature for
a further 1 h. Diphenylchlorophosphine (3.04 g, 0.014 mol)
in diethyl ether (25 cm3) was then added dropwise, at Ϫ78 ЊC,
to the reaction mixture over a further hour before the reaction
mixture was allowed to warm slowly to room temperature with
continuous stirring over a 12 h period. The mixture was
hydrolysed with 10% aqueous NH4Cl (50 cm3), the organic
layer was collected, washed with water (2 × 30 cm3) and dried
over MgSO4. The organic phase was concentrated in vacuo to
ca. 15 cm3 and passed quickly through an alumina column
using 40–60 ЊC light petroleum as eluent. After the solvent was
removed, the white solid was heated in a Kugelröhr oven (80 ЊC,
0.02 mmHg) to remove starting material, yielding the product
as a white solid, mp 76–78 ЊC (5.3 g, 65%) (Found: C, 49.8; H,
2.2; F, 42.6. C24H14F13P requires C, 49.7; H, 2.4; F, 42.6%);
[HRMS (EI) Found Mϩ, 580.06259. C24H16F13P requires Mϩ,
580.06256]; m/z (EI) 580 (Mϩ, 100%), 311 (3), 241 (1), 203 (23)
and 183 (32); δH 7.2–7.5 (14H, um, C6H5 and C6H4); δF Ϫ81.2
Tris(1H,1H,2H,2H-perfluorooctyl)phosphine 3. This was pre-
pared similarly using phosphorus trichloride (2.2 g, 0.016 mol)
affording the product as a colourless solid–liquid, mp 24–26 ЊC
(8.6 g, 50%) (Found: C, 26.7; H, 1.1; P, 2.5. C24H12F39P requires
C, 26.9; H, 1.1; P, 2.9%); m/z (EI) 1072 (Mϩ, 86%), 1053 (67),
953 (4), 803 (4), 739 (21) and 656 (46); δH 2.3 (6H, br t, 3JHH 10,
3
PCH2), 2.1 (6H, um, CH2CF2); δF Ϫ81.0 (3F, t, JFF 14, CF3),
Ϫ114.3 (2F, um, CαF2), Ϫ121.7 (2F, um, CβF2), Ϫ123.0 (2F, um,
CδF2), Ϫ123.7 (2F, um, CεF2), Ϫ126.1 (2F, um, CγF2).
(1H,1H,2H,2H-Perfluorooctyl) diphenylphosphinite 4. To a
rapidly stirred solution of CF3(CF2)5C2H4OH (8.22 g, 22.6
mmol) and trimethylamine (2.3 g, 0.023 mol) in diethyl ether
(75 cm3) was added diphenylchlorophosphine (4.8 g, 21.7
mmol) dropwise over 30 s. Rapid precipitation of [(C2H5)3-
NH]Cl was accompanied by a mild exotherm, and stirring was
continued for a further 10 min. Filtration and concentration of
the filtrate in vacuo gave the crude compound as a viscous oil.
Distillation in vacuo using a Kugelröhr apparatus gave the
product as a colourless liquid (bp 123–125 ЊC/1 mmHg) (11.9 g,
85%); [HRMS (EI) Found Mϩ, 548.05745. C20H14F13OP
requires M, 548.05747]; δH 7.4 (4H, um, o-ArH), 7.3 (6H, um,
m-,p-ArH), 4.0 (2H, vq, 3JHH ~ 3JPH 7, OCH2), 2.4 (2H, tt, 3JHH
7, 3JHF 18, CH2CF2); δF Ϫ81.5 (3F, t, 3JFF 12, CF3), Ϫ113.8 (2F,
um, CαF2), Ϫ122.5 (2F, um, CβF2), Ϫ123.5 (2F, um, CδF2),
Ϫ124.2 (2F, um, CεF2), Ϫ126.8 (2F, um, CγF2).
3
4
3
(3F, tt, JFF 10, JFF 2, CF3), Ϫ111.3 (2F, tm, JFF 15, CαF2),
Ϫ121.9 (2F, um, CβF2), Ϫ122.2 (2F, um, CδF2), Ϫ123.2 (2F, um,
CεF2), Ϫ126.6 (2F, um, CγF2).
Bis(4-tridecafluorohexylphenyl)phenylphosphine 9. This was
prepared similarly using phenyldichlorophosphine (1.253 g,
7 × 10Ϫ3 mol) affording the product as a white solid (3.8 g, 60%)
(Found: C, 40.1; H, 1.4; F, 53.4. C30H13F26P requires C, 40.1; H,
1.45; F, 55.0%); m/z (FAB) 898 (Mϩ, 100%), 821 (12), 503 (24)
and 426 (4); δH 7.2–7.6 (13H, um, C6H5 and C6H4); δF Ϫ81.3
Bis(1H,1H,2H,2H-perfluorooctyl) phenylphosphonite 5. This
was prepared similarly using phenyldichlorophosphine (3.560 g,
0.020 mol) affording the product as a colourless oil (bp 100 ЊC/
0.01 mmHg) (8.998 g, 54%) (Found: C, 31.7; H, 1.5; P, 5.0.
C22H13F26O2P requires C, 31.7; H, 1.6; P, 3.7%); m/z (EI) 850
([M ϩ O]ϩ, 20%), 834 (100), 565 (3), 471 (34); δH ([2H8]toluene)
7.3 (2H, um, o-ArH), 7.0 (3H, um, m-,p-ArH), 3.6 (4H, um,
OCH2), 1.8 (4H, um, CH2CF2); δF([2H8]toluene) Ϫ81.7 (3F, tt,
3
(3F, t, JFF 12, CF3), Ϫ111.4 (2F, um, CαF2), Ϫ121.9 (2F, um,
CβF2), Ϫ122.2 (2F, um, CδF2), Ϫ123.2 (2F, um, CεF2), Ϫ126.6
(2F, um, CγF2).
Tris(4-tridecafluorohexylphenyl)phosphine 10. This was pre-
pared similarly using phosphorus trichloride (0.64 g, 4.7 × 10Ϫ3
mol) affording the product as a white solid, mp 65–67 ЊC (2.9 g,
50%); m/z (FAB) 1216 (Mϩ, 65%), 895 (39), 821 (25), 521 (10)
4
3
3JFF 10, JFF 2, CF3), Ϫ113.9 (2F, tm, JFF 14, CαF2), Ϫ122.3
(2F, um, CβF2), Ϫ123.3 (2F, um, CδF2), Ϫ124.1 (2F, um, CεF2),
Ϫ126.7 (2F, um, CγF2).
and 252 (30); δH 7.5 (6H, d, 3JHH 7, 3,5-ArH), 7.3 (6H, vt, 3JHH
~
3JHP 7, 2,6-ArH); δF Ϫ81.4 (3F, t, 3JFF 12, CF3), Ϫ111.6 (2F, t,
3JFF 14, CαF2), Ϫ122.0 (2F, um, CβF2), Ϫ122.3 (2F, um, CδF2),
Ϫ123.4 (2F, um, CεF2), Ϫ126.6 (2F, um, CγF2).
Tris(1H,1H,2H,2H-perfluorooctyl) phosphite 6. This was pre-
pared similarly using phosphorus trichloride (2.2 g, 0.016 mol)
affording the product as a colourless liquid (bp 125–130 ЊC/0.5
mmHg) (8.96 g, 50%) (Found: C, 25.0; H, 0.9; P, 3.8.
C24H12F39O3P requires C, 25.7; H, 1.0; P, 2.8%); m/z (EI) 1136
1,2-Bis[bis(4-tridecafluorohexylphenyl)phosphino]ethane 11.
This was prepared similarly using 4-BrC6H4C6F13 (7.93 g, 0.017
mol), BunLi (10.4 cm3, 1.6
 in hexane) and 1,2-bis-
(dichlorophosphino)ethane (0.97 g, 4.2 mmol) affording the
product as a white solid mp 88–90 ЊC (4.58 g, 66%) (Found: C,
36.6; H, 1.2; F, 57.3. C50H20F52P2 requires C, 36.0; H, 1.2; F,
59.1%); m/z (FAB) 1703 ([M ϩ O2]ϩ, 6%), 1687 ([M ϩ O]ϩ, 15),
3
([M ϩ O]ϩ); δH 4.0 (6H, vq, JHH ~ 3JPH 7, OCH2), 2.4 (6H, tt,
3JHH 7, 3JHF 18, CH2CF2); δF Ϫ81.9 (3F, t, 3JFF 10, CF3), Ϫ114.4
(2F, um, CαF2), Ϫ122.7 (2F, um, CβF2), Ϫ123.7 (2F, um, CδF2),
Ϫ124.5 (2F, um, CεF2), Ϫ127.1 (2F, um, CγF2).
1671 (Mϩ, 27), 1291 (12), 955 (17) and 821 (38); δH 7.5 (8H, d,
3
4-(Tridecafluorohexyl)bromobenzene 7. A solution of C6F13I
(18.78 g, 0.042 mol) in hexafluorobenzene (40 cm3) was added
dropwise over 3 h to a stirred mixture of 4-bromoiodobenzene
(11.91 g, 0.042 mol), copper powder (5.88 g, 0.092 mol), 2,2Ј-
bipyridine (0.46 g, 2.95 × 10Ϫ3 mol), DMSO (40 cm3) and C6F6
(60 cm3) at 70 ЊC. The mixture was subsequently stirred at 70 ЊC
for 72 h before it was poured into a beaker containing dichlo-
romethane (100 cm3) and water (100 cm3). After filtering, the
organic layer was separated, washed with water (3 × 50 cm3)
and dried over CaCl2 and MgSO4. After concentration to 30
cm3, the crude product was extracted into perfluoro-1,3-
dimethylcyclohexane (3 × 20 cm3) and the solvent removed in
vacuo. Distillation in vacuo using a Kugelröhr apparatus gave
the product as a colourless liquid (bp 80–96 ЊC/0.02 mmHg)
(17.0 g, 89%); m/z (EI) 474/6 ([M]ϩ, 18%), 455/7 (5), 205/7 (100),
126 (30) and 69 (9) (HRMS: Found Mϩ, 473.928 88. C12H4-
F1379Br requires M, 473.9288); δH 7.5 (2H, d, 3JHH 8.5, 3,5-ArH),
3JHH 9, 3,5-ArH), 7.3 (8H, um, 2,6-ArH), 2.1 (4H, vt, JHH
~
3JHP 4, CH2); δF Ϫ81.3 (12F, t, 3JFF 10, CF3), Ϫ111.4 (8F, t, 3JFF
14, CαF2), Ϫ122.0 (8F, um, CβF2), Ϫ122.2 (8F, um, CδF2),
Ϫ123.3 (8F, um, CεF2), Ϫ126.6 (2F, um, CγF2).
4-Tridecafluorohexylphenol 12. A solution of C6F13I (48.204 g,
0.108 mol) in hexafluorobenzene (150 cm3) was added dropwise
to a rapidly stirred solution of 4-iodophenol (24.029 g, 0.109
mol), copper (30.825 g, 0.485 mol), 2,2Ј-bipyridine (1.327 g,
8.5 × 10Ϫ3 mol) in DMSO (150 cm3) over 3 h and the reaction
mixture was then heated at 80 ЊC under nitrogen for 6 days.
After cooling to room temperature the mixture was hydrolysed
with water, filtered and the filtrate washed with dichloro-
methane (2 × 100 cm3). The deep red–brown organic layer was
separated, dried over MgSO4 and concentrated to ca. 100 cm3 in
vacuo. The product was extracted by shaking with perfluoro-
1,3-dimethylcyclohexane (8 × 20 cm3), the washings combined
and the solvent removed in vacuo to leave an off-white solid.
The product was purified by Kugelröhr distillation at 55 ЊC
(0.01 mmHg) to afford 12 as a white crystalline solid (27.977 g,
63%); m/z (EI) 412 ([M]ϩ, 29%), 393 (10) and 143 (100)
(HRMS: Found Mϩ, 412.01327. C12H5F13O requires M,
412.01328); δH 7.3 (2H, d, 3JHH 7.1, 3,5-ArH), 6.9 (2H, d, 3JHH
7.1, 2,6-ArH), 5.2 (1H, s, OH); δF Ϫ81.3 (3F, tt, 3JFF 10, 4JFF 3,
3
3
7.7 (2H, d, JHH 9, 2,6-ArH); δF Ϫ81.3 (3F, t, JFF 10, CF3),
Ϫ111.4 (2F, t, 3JFF 14, CαF2), Ϫ121.9 (2F, um, CβF2), Ϫ122.4 (2F,
um, CδF2), Ϫ123.3 (2F, um, CεF2), Ϫ126.6 (2F, um, CγF2).
(4-Tridecafluorohexylphenyl)diphenylphosphine 8. n-Butyl-
lithium (8.63 cm3 of 1.6  solution in hexane) in diethyl ether
(25 cm3) was added dropwise over
1 h to 4-(trideca-
J. Chem. Soc., Perkin Trans. 1, 1997
3611

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3
CF3), Ϫ110.2 (2F, t, JFF 15, CαF2), Ϫ121.9 (2F, um, CβF2),
Acknowledgements
We would like to thank the EPSRC (P. B., D. G., D. R. P.,
A. M. S.), BP Chemicals Ltd. (D. R. P.) and the Royal Society
(E. G. H.) for financial support.
Ϫ122.4 (2F, um, CδF2), Ϫ123.2 (2F, um, CεF2), Ϫ126.6 (2F, um,
CγF2).
4-Tridecafluorohexylphenyl diphenylphosphinite 13. A solu-
tion of 4-perfluorohexylphenol (2.236 g, 5.43 mmol) and tri-
ethylamine (0.533 g, 5.46 mmol) was added dropwise to a
stirred solution of PPh2Cl (1.082 g, 4.91 mmol) in diethyl ether
(50 cm3) over 1 h. A white precipitate of triethylammonium
chloride formed immediately on addition. The reaction mixture
was stirred for a further 2 h, filtered through Celite and the
solvent removed in vacuo to afford the product as a white solid.
Unreacted starting materials were removed by heating at 60 ЊC
under vacuum (0.01 mmHg) for 3 h. (1.95 g, 67%) (Found: C,
48.6; H, 2.2; P, 5.2. C24H14F13OP requires C, 48.3; H, 2.4; P,
5.2%); m/z (EI) 596 (Mϩ, 82%), 595 (100), 519 (3), 277 (4), 185
(77); δH([2H8]toluene) 7.6 (4H, um, 2,6-ArH), 7.3 (2H, d, 3JHH 9,
3,5-HArRf), 7.15 (6H, um, 3,4,5-ArH), 7.1 (2H, d, 3JHH 9, 2,6-
References
1 D. S. L. Slinn and S. W. Green, in Preparation, Properties and
Industrial Applications of Organofluorine Compounds, ed. R. E.
Banks, Ellis Horwood, Chichester, 1982, p. 45.
2 I. T. Horváth and J. Rábai, Science, 1994, 266, 72; US Pat.
5 463 082, 1995.
3 D. P. Curran and S. Hadida, J. Am. Chem. Soc., 1996, 118, 2531;
D. P. Curran and M. Hoshino, J. Org. Chem., 1996, 61, 6480;
A. Studer and D. P. Curran, Tetrahedron, 1997, 53, 6681; A. Studer,
S. Hadida, R. Ferritto, S. Y. Kim, P. Jeger, P. Wipf and D. P. Curran,
Science, 1997, 275, 823.
4 G. Pozzi, S. Banfi, A. Manfredi, F. Montanari and S. Quici,
Tetrahedron, 1996, 52, 11 879; G. Pozzi, F. Montanari and S. Quici,
Chem. Commun., 1997, 69; G. Pozzi, I. Colombani, M. Miglioli,
F. Montanari and S. Quici, Tetrahedron, 1997, 53, 6145.
5 M. J. Atherton, K. S. Coleman, J. Fawcett, J. H. Holloway, E. G.
Hope, A. Karaçar, L. A. Peck and G. C. Saunders, J. Chem. Soc.,
Dalton Trans., 1995, 4029; J. H. Holloway, E. G. Hope, D. R.
Russell, G. C. Saunders and M. J. Atherton, Polyhedron, 1996, 15,
173; M. J. Atherton, J. Fawcett, J. H. Holloway, E. G. Hope,
A. Karaçar, D. R. Russell and G. C. Saunders, J. Chem. Soc., Dalton
Trans., 1996, 3215.
6 F. Langer, K. Püntener, R. Stürmer and P. Knochel, Tetrahedron:
Asymmetry, 1997, 8, 715.
7 V. C. R. McLoughlin and J. Thrower, Tetrahedron, 1969, 25, 5921;
G. J. Chen, L. S. Chen and K. C. Eapen, J. Fluorine Chem., 1993, 65,
59.
8 G. J. Chen and C. Tamborski, J. Fluorine Chem., 1989, 43, 207.
9 E. G. Hope and A. M. Stuart, unpublished work.
HArRf); δF([2H8]toluene) Ϫ81.4 (3F, tt, JFF 10, JFF 2, CF3),
3
4
Ϫ109.9 (2F, t, JFF 15, CαF2), Ϫ121.7 (2F, um, CβF2), Ϫ122.0
3
(2F, um, CδF2), Ϫ123.1 (2F, um, CεF2), Ϫ126.5 (2F, um, CγF2).
Bis(4-tridecafluorohexylphenyl) phenylphosphonite 14. This
was prepared similarly using 4-perfluorohexylphenol (2.704 g,
6.56 mmol), triethylamine (0.670 g, 6.62 mmol) and PPhCl2
(0.541 g, 3.02 mmol) affording the product as a white solid (bp
160 ЊC/0.01 mmHg) (2.22 g, 79%) (Found: C, 39.8; H, 1.2; F,
51.0; P, 3.4. C30H13F26O2P requires C, 38.7; H, 1.4; F, 53.1; P,
3.3%); m/z (EI) 946 ([M ϩ O]ϩ, 100%), 853 (24); δH([2H8]-
toluene) 7.8 (2H, um, 2,6-ArH), 7.3 (4H, d, 3JHH 9, 3,5-HArRf),
3
7.2 (3H, um, 3,4,5-ArH), 7.0 (4H, d, JHH 9, 2,6-HArRf);
δF([2H8]toluene) Ϫ81.5 (3F, tt, 3JFF 10, 4JFF 2, CF3), Ϫ110.4 (2F,
t, 3JFF 15, CαF2), Ϫ121.7 (2F, um, CβF2), Ϫ122.2 (2F, um, CδF2),
Ϫ123.1 (2F, um, CεF2), Ϫ126.5 (2F, um, CγF2).
10 J. Fawcett, E. G. Hope, R. D. W. Kemmitt, D. R. Paige, D. R.
Russell, A. M. Stuart, D. J. Cole-Hamilton and M. J. Payne, Chem.
Commun., 1997, 1127.
Tris(4-tridecafluorohexylphenyl) phosphite 15. This was pre-
pared similarly using 4-perfluorohexylphenol (2.64 g, 6.4
mmol), triethylamine (0.81 g, 8 mmol) and phosphorus tri-
chloride (0.27 g, 2 mmol) affording the product as a colourless
viscous oil (bp 125 ЊC/0.01 mmHg) (1.38 g, 55.7%) (Found: C,
34.0; H, 1.15; F, 55.35. C36H12F39O3P requires C, 34.2; H, 1.0; F,
58.6%); m/z (EI) 1264 (Mϩ, 10%), 1263 ([M Ϫ H]ϩ, 26), 995 (11)
and 853 (81); δH 7.2 (6H, d, 3JHH 9, 3,5-ArH), 6.9 (6H, d, 3JHH 9,
2,6-ArH); δF Ϫ81.4 (9F, tt, 3JFF 10, 4JFF 3, CF3), Ϫ110.5 (6F, t,
3JFF 14, CαF2), Ϫ121.7 (6F, um, CβF2), Ϫ122.1 (6F, um, CδF2),
Ϫ123.1 (6F, um, CεF2), Ϫ126.5 (6F, um, CγF2).
Paper 7/04872F
Received 8th July 1997
Accepted 22nd August 1997
3612
J. Chem. Soc., Perkin Trans. 1, 1997