Facile synthesis of a monosulfonated triphenylphosphane (TPPMS) derived ligand having strong π-acceptor character

Article abstract of DOI:10.1002/adsc.200606003

Two phenyl rings of triphenylphosphane have been modified by electron-withdrawing trifluoromethyl groups. A methoxy group has been introduced at the para-position of the third ring. Due to the activating effect of the methoxy group, the phosphane can be m

Full text of DOI:10.1002/adsc.200606003

UPDATES
DOI: 10.1002/adsc.200606003
Facile Synthesis of a Monosulfonated Triphenylphosphane
(TPPMS) Derived Ligand having Strong p-Acceptor Character
a
b
c
d,
˝
Henrik Gulyµs, Zoltµn Bacsik, ron Szçllosy, and József Bakos *
a
Institut Catalµ d’Investigació Química, Av. Països Catalans 16, 43007 Tarragona, Spain
Fax : (+34)-977-920-224
Chemical Research Center of the Hungarian Academy of Sciences, 1025 Budapest, Hungary
Institut of General and Analytical Chemistry, University of Technology and Economics, 1521 Budapest, Hungary
Department of Organic Chemistry, University of VeszprØm, Wartha Vince 1, 8201 VeszprØm, Hungary
b
c
d
Fax : (+36)-88-624-469; e-mail: bakos@almos.vein.hu
Received: January 4, 2006; Accepted: May 9, 2006
Supporting information for this article is available on the WWW under http://asc.wiley-vch.de/home/.
Abstract: Two phenyl rings of triphenylphosphane
have been modified by electron-withdrawing tri-
fluoromethyl groups. A methoxy group has been in-
troduced at the para-position of the third ring. Due
to the activating effect of the methoxy group, the
phosphane can be monosulfonated under mild con-
ditions and with complete selectivity. The novel
ligand, sodium 5-[bis-(4-trifluoromethylphenyl)-
phosphanyl]-2-methoxybenzenesulfonate, has been
obtained in quantitative yield, and it has an out-
standing p-acceptor capacity among the known sul-
fonated triarylphosphanes. It is not soluble in water
but soluble in light alcohols and ionic liquids. Its
solubility properties allow facile catalyst separation
without water.
the hydrophilic character of the phosphane is a key
feature in some cases.
Mono- and trisulfonated derivatives of triphenyl-
phosphane
[TPPMS=(3-diphenylphosphanyl)ben-
zenesulfonic acid (1); TPPTS=3,3’,3’’-phosphanetriyl-
tribenzensulfonic acid (2)] are the most frequently
used hydrophilic ligands in both industry and academ-
ic research. Conditions of the sulfonation of triphenyl-
phosphane have continuously been developed over
the last decades in order to improve selectivity, in-
crease yields and suppress oxidation of the products.[2]
Recently we have suggested an alternative approach
that provides access to a wide range of sulfonated tri-
arylphosphanes. Upon activating the phenyl rings
with electron-donating groups, the syntheses do not
suffer from the usual drawbacks of direct sulfonation,
and additionally, the electronic, steric, and hydrophilic
characteristics of the phosphanes can be controlled.[3]
Some of these ligands are already being used in com-
plex-catalyzed reactions with rather promising results
Keywords: p-acceptor character; fluorinated li-
gands; ligand design; P ligands; phosphanes; sulfo-
nation
[e.g.,
TXPTS=trisulfonated
tris(2,4-xylyl)phos-
phane,[4a–c] TAPTS=trisulfonated tris
ACHTRE(UNG p-anisyl)phos-
phane[4c,d]].
Initial catalytic studies with monosulfonated triaryl-
Homogeneous catalysis has been proved to be a pow- phosphanes have drawn our attention to an old
erful tool in a wide range of organic syntheses. Due demand that our original approach could not satisfy.
to an increasing pressure on the chemical society to Sulfonation of triarylphosphanes having one ring acti-
consider environmental aspects of chemical produc- vated by electron-donating groups results in more
tion, certain areas of homogeneous catalysis have basic derivatives of the monosulfonated triphenyl-
become of increasing interest. Aqueous-organic, or- phosphane (3 and 4, Scheme 1).[3] However, several
ganic-organic, fluorous-non-fluorous, ionic liquid-or- catalytic reactions would require ligands having
ganic two-phase systems, supported aqueous phase weaker s-donor, but stronger p-acceptor capacities.
catalysis, etc. allow the separation of the catalysts
from the products, and can be the base of “greener”, tron-withdrawing groups on the phenyl rings possess
sustainable chemical processes.[1]
these desirable features, but their further functionali-
Triphenylphosphane derivatives modified by elec-
Complexes modified with hydrophilic phosphanes zation by direct sulfonation is troublesome. To the
can be suitable catalysts for most of the above-men- best of our knowledge only one attempt has been
tioned techniques, however, concerning applicability, made at the sulfonation of a pronounced p-acceptor
1306
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2006, 348, 1306 – 1310

Monosulfonated Triphenylphosphane (TPPMS) Derived Ligand
UPDATES
Table 1. Carbonyl
stretching
frequencies
of
trans-
RhP2(CO)Cl complexes.[a]
Phosphane
nCO [cmÀ1]
Ref.
[b]
PPh3
1966 (1965)[d]
1964
This work, [6]
This work
This work
[7]
PPh2(p-C6H4OCH3)[c]
Scheme 1. Recently developed derivatives of TPPMS.
5
1983
P(p-C6H4CF3)3
(1990)[d,e]
ACHTREUNG
[a]
Recorded in KBr pellets. The frequencies given in the
Table are the average values of several experiments. For
further details see the Supporting Information.
[b] Parent ligand of 1.
[c]
Parent ligand of 4.
[d] Literature values are in parentheses.
[e]
Recorded in CH2Cl2.
In order to obtain experimental evidence for the
overall electronic nature of the new phosphane, car-
bonyl-rhodium complexes have been prepared and
studied by IR spectroscopy (Table 1). The triarylphos-
phanes compared in Table 1 have similar steric proper-
ties, since they have been modified with para-substitu-
ents only. Thus, the differences in carbonyl stretching
frequencies of their trans-RhP2(CO)Cl complexes can
exclusively be attributed to the electronic nature of the
ligands. In accordance with the Hammett parameters
Scheme 2. Synthesis of 6, a p-acceptor TPPMS derivative.
type triarylphosphane. Fell and Papadogianakis tried of the substituents, the nCO frequency of the trans-
to trisulfonate the tris(p-fluorophenyl)phosphane in Rh(5)2(CO)Cl complex (Table 1) indicates the consid-
25% oleum, however, after 410 h of reaction time, erable p-acceptor character of the new phosphane.
the isolated product contained mainly the disulfonat-
Similar conclusions could be drawn by measuring
1
ed derivative. Besides a lack of selectivity, the re- the JPÀSe coupling constants of the selenides prepared
searchers also observed the usual side reaction of from the triarylphosphanes of Table 1.[8] The JPÀSe
=
1
direct sulfonation: oxidation of the phosphane.[5]
747 Hz coupling constant of Se=P(p-C6H4CF3)2(p-
Since sulfonation of triarylphosphanes having one C6H4OCH3) is considerably higher than those of
activated and two non-activated rings (phenyl) result- Se=PPh2(p-C6H4OCH3) (723 Hz) and Se=PPh3
ed in monosulfonated phosphanes with complete se- (729 Hz), further confirming the increased p-acceptor
lectivity (Scheme 1),[3] we reasoned that (i) parent li- capacity (Table 2).
gands having one activated and two deactivated rings
Sulfonation of 5 has been carried out at room tem-
could certainly be monosulfonated selectively, (ii) de- perature, in 20% oleum (Scheme 2). The correspond-
spite activation of one of the rings, the phosphane ing monosulfonated derivative (6) can be isolated
could be supplied with an overall p-acceptor charac- practically in quantitative yield after one hour of reac-
ter by careful design of its structure.
tion time. The sulfonation is completely ring selective,
Based on this concept, (p-anisyl)bis(p-trifluorome- and only traces of the corresponding phosphane oxide
thylphenyl)phosphane (5) has been prepared by the have been observed (ca. 2–3%, 31P{1H}-NMR).
reaction of ClP(p-C6H4CF3)2 and p-CH3OC6H4MgBr
The new monosulfonated triarylphosphane is not
(Scheme 2). Hammett substituent constants suggest soluble in either water or apolar organic solvents, but
that the para-positioned methoxy group (sparaÀOCH
=
readily soluble in light alcohols, in water-alcohol mix-
3
À0.27) should support the meta-sulfonation of the ani- tures and in ionic liquids.[10] This degree of hydrophil-
sylphosphane 5, but its effect on the basicity of the ic character allows special catalytic applications. For
ligand should be overcompensated by the CF3 groups example, in a methanol-hexane mixture rhodium
(sparaÀCF =0.54).
complexes of 6 are localized in the methanol phase,
3
Adv. Synth. Catal. 2006, 348, 1306 – 1310
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.asc.wiley-vch.de
1307

Henrik Gulyµs et al.
UPDATES
Table 2. 31P{1H}-NMR data of phosphane selenides.[a]
oxygenated by standard methods. Triphenylphosphane and
styrene were purchased from Sigma–Aldrich and used as re-
dACTHEURNG ACHTRE(UNG Ar’)2 Ref.
(31P{1H}) Se=PAr
A
ceived. [Rh(CO)2Cl]2,[14] [Rh(NBD)2]BF4,[15] (p-anisyl)diphe-
ACHTREUNG
Phosphane
1JPÀSe [Hz]
nylphosphane,[3b] and the phosphane selenides[16] were pre-
pared according to the literature. Sulfonation of (p-anisyl)di-
phenylphosphane was published earlier.[2g] Monosulfonated
triphenylphosphane was prepared by a slightly modified lit-
erature method (see below).[1 g] 31P{1H}-, 1H NMR and
13C{1H}- spectra were recorded on either a Varian Unity 300
spectrometer operating at 121.42 MHz, 300.15 MHz and
75.43 MHz, respectively, or on a Bruker DRX-500 spectrom-
eter operating at 202.45 MHz, 500.13 MHz and 125.76 MHz,
respectively. Infrared spectra were recorded on Nicolet
AVATAR 330, Bio-Rad (Digilab) FTS-185 and Bio-Rad
(Digilab) FTS-60 FT-IR spectrometers. Gas chromatograph-
ic analyses were run on a Hewlet-Packard 5830 A gas chro-
matograph (30 m SPB-1 column, film thickness 0.1 mm, N2
carrier gas 2 mLminÀ1).
PPh3
729
723
747
765
This work
This work
This work
[9]
PPh2(p-C6H4OCH3) 36.1
5
P(p-C6H4CF3)3
35.4
34.9
[a]
Recorded in CDCl3.
which is well-separated from the hexane. On heating
the mixture above 408C, it forms one single phase.
On cooling, the orange alcohol phase separates from
the colorless hydrocarbon phase again. A similar
system has been described by Bianchini and is based
on the monosulfonated tridentate ligand sulphos (p-
(CH2PPh2)3.[11] This type of solvent
NaO3S-C6H4)CH2CACHTREUNG
systems allows facile catalyst separation without
water, thus, it can be an alternative to the fluorous bi-
phasic systems.[12]
(4-Methoxyphenyl)ACHTRE{UNG bis[4-(trifluoromethyl)phenyl]}-
phosphane (5)
It is worth mentioning that the sulfonate group also
considerably influences the electronic nature of the
4-Anisylmagnesium bromide (24 mmol, dissolved in 25 mL
1
phosphane. The JPÀSe =754 Hz coupling constant ob- THF) was slowly added to chlorbis(trifluormethylphenyl)-
phosphane (7.69 g, 21.6 mmol, dissolved in 75 mL Et2O) at
À5 to +38Cinternal temperature (ice/salt bath). The reac-
tion mixture was stirred for 3 h while the temperature
reached 158C. The bath was removed. The reaction mixture
was stirred further and allowed to warm to room tempera-
ture (30 min, 238C). The reaction mixture was cooled again
(ice/salt bath, À58Cinternal temperature) and carefully
quenched with NH4Cl solution (50 g, 10%). The aqueous
phase was removed using a cannula. The organic phase was
washed with NaHCO3 solution (2”25 g, 10%), then water
(2”25 mL). The organic phase was dried over MgSO4. The
served for the selenide of 6 indicates that the sulfona-
tion further increases the p-acceptor capacity.[13]
The beneficial effect of the pronounced p-acceptor
character of 6 has already been observed in several
catalytic reactions. For example, an interesting elec-
tronic effect has been found in the course of a study
on the rhodium-catalyzed hydrogenation of cinnamic
aldehyde. An in situ formed 1/RhACHTRE(UNG NBD)2BF4 catalyst
provided only 12% conversion under the applied con-
ditions (methanol, 20 atm of H2, room temperature,
1:200 Rh to substrate ratio, 40 min). The correspond- solvent was removed under vacuum. The crude product
(dense yellow oil) was crystallized from methanol. (Crystal-
lization was initiated in a refrigerator.) At this stage the
phosphane contained ca. 3% of phosphane oxide and ~3%
of H(O)P(p-C6H4CF3)2 (31P{1H}-NMR). It was recrystallized
from hot MeOH/water (V/V=45/4) to give 2.77 g of pure
product. The mother liquors were combined, the solvent
was removed, then the residue was recrystallized similarly
(VMeOH/Vwater =15) to give further 1.62 g of pure product.
Total yield: 4.39 g (48%); white microcrystalline solid; mp
52–558C; 1H NMR (CDCl3): d=3.75 (s, 3H, OCH3), 6.86
ing rhodium complex modified by the sterically simi-
lar but more basic sulfonated phosphane 4 proved to
be even less active (4% conversion). However, the
rhodium complex of 6 hydrogenated 76% of the cin-
namic aldehyde to phenylpropanal, practically with
complete selectivity (>99%).
The catalytic application mentioned above might
confirm that updating this synthetic approach can
provide access to useful ligands. Currently, following
the presented approach, we are compiling a pool of
3
4
(dd, JHH ꢀ 8.8 Hz, JPH ꢀ 0.8 Hz, 2H, C3{p-C6H4OCH3}-
3
3
hydrophilic phosphanes of a fine scale of electronic H), 7.21 (pseudo t, JPH ꢀ 8.8 Hz, JHH ꢀ 8.8 Hz, 2H, C2{p-
3
3
C6H4OCH3}-H), 7.30 (broad pseudo t, JPH ꢀ 8 Hz, JHH
ꢀ
ꢀ
nature. This set of ligands should support our efforts
to develop efficient and environmentally benign cata-
lytic systems.
3
8 Hz, 4H, C2{p-C6H4CF3}-H), 7.51 (broad pseudo d, JHH
8 Hz, 4H, C3{p-C6H4CF3}-H); 13C{1H}-NMR (CDCl3): d=
3
55.31 (s, OCH3), 114.61 (d, JPC =9.7 Hz, C3{p-C6H4OCH3}),
123.84 (q, 1JFC =271.3 Hz, CF3), ~125.05 (d, C1{p-
2
C6H4OCH3}), 125.11 (m, C3{p-C6H4CF3}), 130.64 (q, JFC
=
31.5 Hz, C4{p-C6H4CF3}), 133.27 (d, 2JPC =19.4 Hz, C2{p-
C6H4CF3}), 135.84 (d, 2JPC =24.2 Hz, C2{p-C6H4OCH3}),
142.11 (d, 1JPC =14.5 Hz, C1{p-C6H4CF3}), 160.86 (s, C4{p-
C6H4OCH3}); 31P{1H}-NMR (CDCl3): d=À6.9 (s); anal.
calcd. for C21H15F6OP (Mr =428.31): C58.89, H 3.53; found:
C58.71, H, 3.17.
Experimental Section
General Remarks
All manipulations were carried out under argon using
Schlenk techniques. Solvents were purified, dried and de-
1308
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ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 2006, 348, 1306 – 1310

Monosulfonated Triphenylphosphane (TPPMS) Derived Ligand
UPDATES
ed), 7.84 (broad d, J ꢀ 7.6 Hz, 1H, sulfonated), 7.87 (broad
Sodium 5-[Bis(4-trifluoromethylphenyl)phosphanyl]-
2-methoxybenzenesulfonate (6)
d,
J
ꢀ
7.5 Hz, 1H, sulfonated) ppm; 13C{1H}-NMR
(CD3OD): d=127.45 (s, C4{sulfonated}), 129.57 (d, JPC
=
6.1 Hz, sulfonated), 129.74 (d, 3JPC =7.2 Hz, meta-phenyl),
130.12 (s, para-phenyl), 131.97 (d, JPC =22.9 Hz, sulfonated),
Fuming sulfuric acid (2.5 mL, 20% of free SO3) was trans-
ferred in a round-bottom flask under argon. The flask was
placed in a salt/ice bath, and (4-anisyl)bis(4-trifluoromethyl-
phenyl)phosphane (5, 1 g, 2.33 mmol) was added to the
fuming sulfuric acid in small portions. The bath was re-
moved and the reaction mixture was stirred for one hour.
The flask was placed in an ice/salt bath again and crushed
ice (~10 g) was added over a 30 min period. In the course of
the procedure the phosphonium salt precipitated as a sticky
material. Sufficient blending was maintained by shaking the
flask gently. The acidic reaction mixture was carefully neu-
134.80 (d, 2JPC =19.1 Hz, ortho-phenyl), 136.27 (d, JPC
=
1
18.2 Hz, sulfonated), 137.99 (d, JPC =10.8 Hz, ipso-phenyl),
139.68 (d, JPC =14.6 Hz, sulfonated), 146.59 (d, JPC =6.2 Hz,
sulfonated); 31P{1H}-NMR (CD3OD): d=À5.0 (s) ppm;
anal. calcd. for C18H14NaO4PS·H2O (Mr =382.28): P 8.10, S
8.37, Na 6.01; found: P 8.07, S 8.64, Na 5.94. Degree of sul-
fonation: S/P=1.03.
tralized with aqueous NaOH solution (3.95 g NaOH in Rh(phosphane)2(CO)Cl Complexes
30 mL water). The pH of the suspension was set to ~7.
(Controlled by special pH paper.) The aqueous suspension
was transferred in a 500 mL flask under argon, and the
water was removed under vacuum. (Due to intensive foam
formation, the use of a smaller flask is not advisable.) The
white residue was extracted with methanol (2”50 mL).
Water (10 mL) was added to the methanol solution, then
the solvent was removed. The product is a white solid.
Yield: 1.20 g (94%); 1H NMR (CD3OD): d=3.94 (s, 3H,
[Phosphane=PPh3, PPh2(p-C6H4OCH3),
P(p-C6H4CF3)2(p-C6H4OCH3)]
Phosphanes (0.168 mmol) dissolved in CH3CN (2 mL) were
added to [Rh(CO)2Cl]2 (15.6 mg, 0.04 mmol) dissolved in
CH3CN (1 mL). The Schlenk flask of the phosphanes was
rinsed with further 1 mL of CH3CN. The reaction mixtures
were stirred for 60–120 min. The solvent was removed under
vacuum. The isolated solids were washed with Et2O and
dried under vacuum for 15 min at room temperature. (The
last operation should not be carried out in the case of 5,
since the complex is considerably soluble in Et2O.) Each
complex was also prepared in a similar manner using
CH2Cl2 as solvent instead of CH3CN. 31P{1H}-NMR (CDCl3)
spectra were recorded of the products prepared in CH3CN.
3
4
OCH3), 7.17 (dd, JHH =8.4 Hz, JPH =0.7 Hz, 1H, C5{sulfo-
nated}-H), 7.41–7.51 (m, 5H, C2{p-C6H4CF3}-H, C6{sulfo-
3
nated}-H), 7.66 (broad pseudo d, JHH ꢀ 8 Hz, 4H, C3{p-
C6H4CF3}-H), 7.96 (dd, 3JPH =7.7 Hz, 4JHH =2.4 Hz, 1H,
C2{sulfonated}-H); 13C{1H}-NMR (CD3OD): d=56.49 (s,
OCH3), 113.77 (d, 3JPC =9.7 Hz, C3{p-C6H4OCH3}), 125.32
1
31P{1H}-NMR data of the complexes are as follows. Rh-
(q, JFC =271.3 Hz, CF3), 125.91 (d, JPC =9.7 Hz, sulfonated),
2
126.28 (m, 3JFC =3.6 Hz, C3{p-C6H4CF3}), 131.70 (q, JFC
=
1
A
U
C6H4OCH3)]2(CO)Cl: d=27.6 ppm (d, 1JRhP =127 Hz);
Rh[P(p-C6H4CF3)2(p-C6H4OCH3)]2(CO)Cl: d=30.5 ppm (d,
1JRhP =128 Hz). IR (KBr pellets) spectra were recorded of
each batch using three different FT-IR spectrometers. 6–10
spectra were recorded of each complex. Depending on the
conditions of the syntheses and the measurements, the nCO
32.7 Hz, C4{p-C6H4CF3}), 133.67 (d, JPC =10.9 Hz, sulfonat-
ed), 134.60 (d, 2JPC =19.4 Hz, C2{p-C6H4CF3}), 135.61 (d,
2JPC =23.0 Hz, C2{sulfonated}), 139.54 (d, 2JPC =24.2 Hz,
C2{sulfonated}), 143.68 (broad d, 1JPC =14.5 Hz, C1{p-
C6H4CF3}), 159.53 (s, C4{sulfonated}); 31P{1H}-NMR
(CD3OD): d=À2.4 (s) ppm; MS (ESI-): m/z=507.1
[MÀNa+]; MS (ESI+): m/z=508.9 [MÀNa+ + 2H+]+; anal.
calcd. for C21H14F6NaO4P·H2O (Mr =548.37): P 5.64, S 5.84,
Na 4.19; found: P 5.58, S 5.81, Na 3.89. Degree of sulfona-
tion: S/P=1.01.
values fell in the following ranges: RhACHTREUNG
1964.8–1966.2 cmÀ1
1963.2–1965.1 cmÀ1
;
;
RhACHTREUNG
Rh[P(p-C6H4CF3)2(p-C6H4OCH3)]2-
(CO)Cl: n=1982.3–1984.0 cmÀ1. The average (rounded) nCO
values are summarized in Table 1.
Sodium (Diphenylphosphanyl)benzenesulfonate (1)
Phosphane Selenides [Phosphane=PPh3,
PPh2(p-C6H4OCH3), 5, 6]
Triphenylphosphane (20.0 g, 76.3 mmol) was slowly added to
fuming sulfuric acid (50 mL, 20% of free SO3). When the
phosphane had completely dissolved, the homogenous reac-
tion mixture was heated at 97–988Cfor 75 min. The reaction
mixture was allowed to cool to room temperature, and then
it was poured on crushed ice (400 g). The pH of the milky
reaction mixture was set to ~4 using 50% NaOH solution.
The precipitate was filtered and recrystallized twice from
water [1) 550 mL of warm water, then refrigerator over-
night. 2) 60 mL of hot water.] The second recrystallization
yielded 7.0 g analytically pure TPPMS monohydrate. In a re-
frigerator further 3.5 g of pure product crystallized from the
mother liquor in two days. Total yield: 10.5 g (36%);
1H NMR (CD3OD): d=7.24–7.36 (m, 11H, Ph and 1H sul-
fonated), 7.40 (broad pseudo t, J ꢀ 7–8 Hz, 1H, sulfonat-
The selenides were prepared by the reaction of the phos-
phanes and elemental selenium in refluxing CHCl3 (EtOH
in the case of 6) according to a literature method.[16] 31P{1H}-
NMR (CDCl3) spectra were recorded in CDCl3. 31P{1H}-
NMR data of the complexes are as follows: Se=PPh3: d=
37.3 ppm (d, 1JSeÀP =729 Hz); Se=PPh2(p-C6H4OCH3): d=
1
36.1 ppm (d, JSeÀP =723 Hz); selenide of 5: d=35.4 ppm (d,
1JSeÀP =747 Hz); selenide of 6: d=35.3 ppm (d, JSeÀP
=
1
754 Hz).
Adv. Synth. Catal. 2006, 348, 1306 – 1310
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.asc.wiley-vch.de
1309

Henrik Gulyµs et al.
UPDATES
G. P. Albanese, R. M. Manetsberger, P. Lappe, H. Bahr-
mann, Angew. Chem. 1995, 107, 893–895, Angew.
Chem. Int. Ed. Engl. 1995, 34, 811–813; g) F. Joó, J.
Kovµcs, . Kathó, A. C. BØnyei, T. Decuir, D. J. Dare-
nsburg, in: Inorg. Synth. (Ed.: M. Y. Darensbourg),
1998, Vol. 32, pp. 1–8; h) S. Hida, P. J. Roman Jr.,
A. A. Bowden, J. D. Atwood, J. Coord. Chem. 1998, 43,
345–348; i) T. Thorpe, S. M. Brown, J. Crosby, S. Fitz-
john, J. P. Muxworthy, J. M. Williams, Tetrahedron Lett.
2000, 41, 4503–4505.
Catalytic Reactions
[RhACHTREUNG(NBD)2]BF4 (7.5 mg, 0.02 mmol), sulfonated phosphane
(0.1 mmol), MeOH (4 mL), NaOH (10 ml, 2m) were trans-
ferred successively in a Schlenk tube under argon. The mix-
ture was stirred for 30 min. Cinnamic aldehyde (529 mg,
4 mmol) was added, then the reaction mixture was transfer-
red in a stainless steel autoclave (20 mL). The autoclave was
pressurized with H2 to 20 bar, then the reaction mixture was
agitated (220 sÀ1) at room temperature for 40 min. After the
run the autoclave was vented carefully. The reaction mixture
was poured into a Schlenk tube filled with argon, then ana-
lyzed by GC.
˝
[3] a) H. Gulyµs, . Szçllosy, B. E. Hanson, J. Bakos, Tetra-
hedron Lett. 2002, 43, 2543–2546; b) H. Gulyµs, .
˝
Szçllosy, P. Szabó, P. Halmos, J. Bakos, Eur. J. Org.
Chem. 2003, 2775–2781.
[4] a) E. C. Western, J. R. Daft, E. M. II Johnson, P. M.
Gannett, K. H. Shaughnessy, J. Org. Chem. 2003, 68,
6767–6774; b) L. R. Moore, K. H. Shaughnessy, Org.
Lett. 2004, 6, 225–228; c) H. Gulyµs, A. C. BØnyei, J.
Bakos, Inorg. Chim. Acta 2004, 357, 3094–3098; d) X.
Wang, H. Y. Fu, X. Li, H. Chen, Catal. Commun. 2004,
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Supporting Information
1
31P{1H}-NMR and H NMR spectra of 5. 31P{1H}-NMR spec-
tra of two subsequent batches of the isolated 6. 1H NMR
spectrum of 6. 31P{1H}-NMR and H NMR spectra of trans-
1
RhACHTREUNG[PPh2(p-C6H4OCH3)]2(CO)Cl. Pictures of methanol-
hexane mixture in the presence of Rh complexes of 6 at dif-
ferent temperatures.
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Acknowledgements
1
[8] For examples of the use of JPÀSe coupling constants to
assess electronic nature of phophanes, see: E. Genin,
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1733–1741, and references cited therein.
We gratefully acknowledge financial support of this work by
the Hungarian National Science Foundation (OTKA T
046825). We thank Mr. BØla Édes for his skillful technical as-
sistance.
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