Highly regioselective hydroformylation with hemispherical chelators

Article abstract of DOI:10.1002/chem.200800747

The hemispherical diphosphites (R,R)- or (S,S)-5,11,17,23-tetratert-butyl- 25,27-di(OR)-26,28-bis(1,1′-binaphthyl-2,2′-dioxyphosphanyloxy) -calix[4]arene (R = OPr, OCH₂Ph, OCH₂-naphtyl, O-fluorenyl; R = H, R' = OPr) (L^R), all with C₂ symmetry, have been synthesised starting from the appropriate di-O-alkylated calix[4]-arene precursor. In the presence of [Rh(acac)(CO)₂], these ligands straightforwardly provide chelate complexes in which the metal centre sits in a molecular pocket defined by two naphthyl planes related by the C ₂ axis and the two apically situated R groups. Hydroformylation of octene with the L^Pr/Rh system turned out to be highly regioselective, the linear-to-branched (l:b) aldehyde ratio reaching 58:1. The l:b ratio significantly increased when the propyl groups were replaced by -CH ₂Ph (l:b = 80) or -CH₂naphthyl (1:b = 100) groups, that is, with substituents able to sterically interact with the apical metal sites, but without inducing an opening of the cleft nesting the catalytic centre. The trend to preferentially form the aldehyde the shape of which fits with the shape of the catalytic pocket was further confirmed in the hydroformylation of styrene, for which, in contrast to catalysis with conventional diphosphanes, the linear aldehyde was the major product (up to ca. 75 % linear aldehyde). In the hydroformylation of frarts-2-octene with the L^benzyl/ Rh system, combined isomerisation/hydroformylation led to a remarkably high 1:b aldehyde ratios of 25, thus showing that isomerisation is more effective than hydroformylation. Unusually large amounts of linear products were also observed with all the above diphosphites in the tandem hydroformylation/amination of styrene (1:b of ca. 3:1) as well as in the hydroformylation of allyl benzyl ether (1:b ratio up to 20).

Full text of DOI:10.1002/chem.200800747

DOI: 10.1002/chem.200800747
Highly Regioselective Hydroformylation with Hemispherical Chelators
David SØmeril,*[a] Dominique Matt,*[a] and Loïc Toupet[b]
7144
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2008, 14, 7144 – 7155

FULL PAPER
Abstract: The hemispherical diphos-
phites (R,R)- or (S,S)-5,11,17,23-tetra-
tert-butyl-25,27-di(OR)-26,28-bis(1,1’-
binaphthyl-2,2’-dioxyphosphanyloxy)-
regioselective, the linear-to-branched
(l:b) aldehyde ratio reaching 58:1. The
l:b ratio significantly increased when
the propyl groups were replaced by
-CH2Ph (l:b=80) or -CH2naphthyl
(l:b=100) groups, that is, with substitu-
ents able to sterically interact with the
apical metal sites, but without inducing
an opening of the cleft nesting the cat-
alytic centre. The trend to preferential-
ly form the aldehyde the shape of
which fits with the shape of the catalyt-
ic pocket was further confirmed in the
hydroformylation of styrene, for which,
in contrast to catalysis with convention-
al diphosphanes, the linear aldehyde
was the major product (up to ca. 75%
linear aldehyde). In the hydroformyla-
calix[4]arene
(R=OPr,
OCH2Ph,
OCH2-naphtyl, O-fluorenyl; R=H,
R’=OPr) (LR), all with C2 symmetry,
have been synthesised starting from
the appropriate di-O-alkylated calix[4]-
arene precursor. In the presence of
tion of trans-2-octene with the Lbenzyl
/
Rh system, combined isomerisation/hy-
droformylation led to a remarkably
high l:b aldehyde ratios of 25, thus
showing that isomerisation is more ef-
fective than hydroformylation. Unusu-
ally large amounts of linear products
were also observed with all the above
diphosphites in the tandem hydrofor-
mylation/amination of styrene (l:b of
ca. 3:1) as well as in the hydroformyla-
tion of allyl benzyl ether (l:b ratio up
to 20).
[Rh
A
these
ligands
straightforwardly provide chelate com-
plexes in which the metal centre sits in
a molecular pocket defined by two
naphthyl planes related by the C2 axis
and the two apically situated R groups.
Hydroformylation of octene with the
LPr/Rh system turned out to be highly
Keywords: calixarenes · homogene-
ous catalysis · hydroformylation ·
phosphites · rhodium
Introduction
Catalytic olefin hydroformylation with CO/H2 mixtures cur-
rently constitutes the main route for the production of
linear C3–C18 aldehydes. In most plants, these are subse-
quently converted into plasticiser and detergent alcohols, as
well as acids and other derivatives.[1–4] The world production
of oxo chemicals today reaches almost 10 million tons. Most
of the aldehydes are produced by low-pressure hydrofor-
Scheme 1. Trigonal-bipyramidal intermediates in the rhodium-catalysed
octene hydroformylation by using chelating diphosphanes with large bite
angles (ee and ae stand for equatorial–equatorial and axial–equatorial
configurations, respectively).
A
kenes, affords mainly linear aldehydes when the catalyst is
based on triarylphosphane ligands, for example, PPh3.
Owing to the increasing importance of oxo products, consid-
erable efforts have been devoted in recent years to improv-
ing the regioselectivity of hydroformylation reactions. In
particular, research has focussed on the design and use of di-
phosphanes characterised by a large natural bite angle.[5–12]
Chelators of this type are known to favour the formation of
trigonal-bipyramidal hydrido–carbonyl species in which the
phosphorus atoms both occupy equatorial sites (ee configu-
ration in Scheme 1). Such a conformation often increases
the linear aldehyde selectivity, but does not constitute a
must for high regioselectivity. The latter is in fact controlled
by the ligand bite angle, which, if having the proper value,
may drive the hydride-transfer step towards the formation
of a linear rhodium–alkyl intermediate, which in turn leads
to a linear aldehyde.[1]
In the last decade, calixarenes have proved to be valuable
scaffolds for the synthesis of diphosphanes with strong che-
lation properties.[13–16] Of particular interest are calix[4]ar-
enes bearing two phosphite units distally located at the
lower
rim,[17]
here
termed
1,3-calix[4]diphosphites
(Scheme 2). X-ray studies have revealed that these ligands
may give chelate complexes in which the P-M-P angles are
significantly larger than those observed in related complexes
with non-chelating ligands.[18,19]
In a recent preliminary com-
munication, we reported that
the use of 1,3-calix[4]diphos-
phites in which both phospho-
rus atoms are substituted by the
bulky 1,1’-binaphthalene-2,2’-
dioxy (“bino”) group led to a
high proportion of linear alde-
hydes in the hydroformylation
[a] Dr. D. SØmeril, Dr. D. Matt
Laboratoire de Chimie Inorganique MolØculaire
Institut de Chimie UMR 7177, UniversitØ de Strasbourg (France)
Fax : (+33)3-90-24-17-49
E-mail: dsemeril@chimie.u-strasbg.fr
dmatt@chimie.u-strasbg.fr
[b] Dr. L. Toupet
Groupe Mati›re CondensØe et MatØriaux
UMR CNRS 6626, UniversitØ de Rennes
l Campus de Beaulieu, F-35042 Rennes cedex (France)
Scheme 2. General formula of
1,3-calix[4]diphosphites bear-
of octene. This effect is mark- ing secondary Z groups.
Chem. Eur. J. 2008, 14, 7144 – 7155
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
7145

D. Matt, D. SØmeril and L. Toupet
edly stronger than with related calixarenes containing P-
(OPh)2 substituents.[19] The high regioselectivity may be at-
tons, while the 31P NMR spectra exhibit a single signal in the
phosphite region (d=118.7–134.4 ppm). The conical struc-
ture of the backbone was further confirmed by a single-crys-
tal X-ray diffraction study of diphosphite 12 (Figure 1), al-
ACHTREUNG
tributed to the ability of the phosphorus substituents to
form a tight pocket about the rhodium centre, which, in line
with van Leeuwenꢁs proposals,[20,21] favours the formation of
linear products. Having four phenolic oxygen atoms at the
lower rim of the calixarene platform enables the tethering
of two further substituents (Z) so as to create, together with
the two P(OR)2 moieties, a hemispherical ligand environ-
ment that may then result in a greater “embrace” of the
metal. In the present contribution, we describe a series of
binol-derived 1,3-calix[4]diphosphites bearing various Z side
groups and show that these may be used efficiently in vari-
ous olefin hydroformylations. The results presented herein
illustrate how the introduction of properly chosen Z groups
may significantly improve the regioselectivity of the reac-
tion.
Figure 1. Molecular structure of 12 (S,S). Interplanar angle between con-
nected naphthyl moieties: 24.88; dihedral angles between facing phenoxy
rings of the calixarene: 72.68 (O1/O2), 24.78 (O3/O4). The molecule crys-
tallises with a molecule of toluene lying out of the cavity (not shown).
Results and Discussion
Synthesis of diphosphites: The double deprotonation with
NaH of the appropriate, distally O-dialkylated precursor (1–
5) followed by reaction with (S)- or (R)-(1,1’-binaphthalene-
2,2’-diyl)chlorophosphite (Scheme 3) led to the diphosphites
6–12. The compounds were obtained after workup (see Ex-
perimental Section) in yields between 14 and 75%. As ex-
pected, identical NMR spectra were obtained for the diaste-
reoisomeric pairs 6 and 7 as well as for 8 and 9. The “cone”
form of the calixarenes was inferred from the corresponding
13C NMR spectra, which show ArCH2Ar signals in a range
typical for this conformation (observed chemical shifts be-
tween d=31.43 and 33.55 ppm).[22] In keeping with a C2-
though the cone is flattened so that the O-propyl groups of
12 are pushed towards the calixarene axis and form with the
two naphthyl groups a molecular pocket. Careful examina-
tion of the crude reaction mixtures revealed for all of them,
except for that leading to 12, the presence of a minor by-
product, namely a “partial cone” isomer (vide infra), which
could be separated straightforwardly by fractional crystalli-
sation. In the case of 12, several by-products were formed
that were not identified. Two partial cone conformers, 13
and 14, could be isolated as pure products.
The assignment of a partial cone conformation was made
on the basis of the corresponding 13C NMR spectra, which
each shows four ArCH2Ar sig-
1
symmetrical structure, each H NMR spectrum displays two
distinct AB patterns for the diastereotopic ArCH2Ar pro-
nals, two being typical for CH2
groups bridging anti-oriented
phenol rings, the other two in
accord with methylene groups
linking syn-oriented rings. The
31P NMR spectra both display
two distinct phosphite signals
separated by about 10 ppm. A
single-crystal X-ray diffraction
study was carried out for di-
phosphite 14, which confirmed
the proposed conformation
and revealed that the phospho-
rus atoms belong to anti-ori-
ented phenol rings (Figure 2)
of two distal phenol rings.
The ability of the conical
1,3-calixdiphosphites described
above to form chelate com-
plexes with rhodium was
Scheme 3. Synthesis of calixarenes 6–12.
proved by reacting 8 with [Rh-
7146
www.chemeurj.org
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2008, 14, 7144 – 7155

Hydroformylation
FULL PAPER
good crystals, but is likely to be close to that of its analogue
in [Pd
(h3-allyl)(6)]PF6,[19] in which the metal centre sits on
G
the calixarene axis in a kind of cleft formed by two symmet-
rically situated naphthyl units that are perpendicular to the
P-M-P plane. In this complex, the ligand bite angle is 107.58.
MM2 calculations[23] caried out for [Rh(8)] reveal that the
two benzyl side groups delineate together with the two “P-
bino” moieties a hemispherical pocket (Figure 3). As in the
palladium complex, the naphthyl units forming the cleft are
inclined by about 458 with respect to the orientation defined
by the dz2 orbital.
Figure 3. Calculated MM2 structures of the Rh·8 moiety. The calculations
were carried out with metal parameters for a square-planar (left) and a
trigonal-bipyramidal (right) coordination geometry.
Finally, we checked that the presence of the sterically en-
cumbered fluorenyl substituents in 16 (obtained by reacting
[Rh
the complex.
A
Figure 2. Molecular structure of 14. The tBu groups have been omitted
for clarity. Interplanar angle between connected naphthyl moieties: 31.18
and 32.18. The molecule crystallises with a molecule of toluene (not
shown).
A
yield (75% after workup). Complex 15 is highly soluble in
hexane. Its mass spectrum shows a strong peak at 1659.59
corresponding to the [M]+ ion. All NMR spectra of 15 are
consistent with a C2-symmetrical molecule. For example, the
31P NMR spectrum shows
126.4 ppm (J(Rh,P)=327 Hz), while the corresponding
a doublet centred at d=
G
1H NMR spectrum displays two AB systems for the
ArCH2Ar methylenic protons. The solid-state structure of
the M·8 moiety could not be determined because of lack of
Catalytic
hydroformylation:
Only those diphosphites with a
conical calixarene skeleton,
namely the hemispherical li-
gands 6–12, were assessed in
hydroformylation
reactions
(Scheme 5). The olefins tested
were octene, trans-2-octene, sty-
rene, allyl benzyl ether and nor-
bornene. The catalysts were
generated in situ.
Scheme 4. Synthesis of complex 15.
Chem. Eur. J. 2008, 14, 7144 – 7155
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
7147

D. Matt, D. SØmeril and L. Toupet
be seen when considering the poor selectivity (l:b=3.3) ob-
tained with ligand 11 with two fluorenyl units. In fact, these
modify the metal confinement as a result of strong steric in-
teractions with both the calixarene backbone and the naph-
thyl groups, thereby modifying the degree of confinement of
the metal olefin unit (vide infra). We found that the high
preference obtained for the linear product with 8 and 10
was maintained until the end of the reaction; for example,
the l:b ratio was still 80 after 24 h reaction time with diphos-
phite 8 (Table 1, entry 3). The presence of four tert-butyl
substituents on the upper rim of the calixarene turned out
to have a beneficial influence on the activity and on the re-
gioselectivity. Thus, in contrast to the reactions carried out
with the tetrabutylated calixarene ligands, those performed
with diphosphite 12 resulted in a decrease of aldehyde selec-
tivity with time (l:b=91.6 at 19.7% conversion, l:b=34.0 at
98.5% conversion; Table 1, entry 8), the only branched alde-
hyde produced being 2-methyl octanal. A similar l:b de-
crease has already been observed by Bçrner et al. with
other phosphorus-containing calixarenes.[25] The reason for
the selectivity decrease with 12 remains unclear. Possibly
ligand 12 displays a weaker chelating power and therefore
decoordinates gradually, hence leading to a less selective
catalyst. The fact that 2-methyl octanal is the only branched
aldehyde seen suggsts that under the conditions used, this
aldehyde originates directly from 1-octene rather than from
2-octene, since hydroformylation of the latter was shown to
result also in 2-ethyl heptanal.
Scheme 5. Rhodium-catalysed hydroformylation of olefins.
1-Octene hydroformylation: These tests were carried out at
808C under 20 bar of CO/H2 using [Rh(acac)(CO)2] as pre-
A
cursor. With the exception of 11 (see below), all ligands
gave remarkably high linear-to-branched (l:b) aldehyde
ratios (l:b=34–102) provided an excess of diphosphite was
used (Table 1, see e.g., entries 1–4). As observed by other
Table 1. Rhodium-catalysed hydroformylation of 1-octene using diphos-
phites 6, 8–12.[a]
L
L/
t
Conv[b] TOF[c]
Product distribution
l:b[f]
Rh [h] [%]
Olefins[d]
[%]
Aldehydes[e]
[%]
1
2
3
6
10
1
1.2 34.51440
17.0
620
660
480
1190
670
17.5
8.0 5
51.8
9.4
53.8
20.9
8
1
98.5
13.2
46.7
3.8
22.4
3.0
56.3
6
8
3.9
2.5
8
76.2
10
1
23.9
>100[g]
78.3
4
53.3
3.5
49.8
24
1
24
1
24
1
4
4
1
4
24
87.3
23.1
95.5
24.2
94.5200
14.4
48.5600
28.8
19.7
51.0
180
1150
200
12.1
2.6
22.6
1.8
75.2
20.5
72.9
22.4
80.1
4
5
6
8
9
1
7.2
1.9
10
1200
>100[g]
13.6
720
29.5
360
980
640
80.9
71.0
10 10
6.3
19.0
2.0
7.9
22.2
5
8.1
101.6
26.8
11.8
28.8
34.0
>100[g]
In all the tests in which L:Rh ratios of ten were applied
internal olefins were produced, the proportion of 1-octene
converted to internal olefins being in some instances almost
as important as that transformed into aldehydes. The only
calixarenes for which olefin isomerisation remained relative-
ly low with respect to hydroformylation were the benzyl-
substituted calixarenes 8 and 9 (Table 1, entries 3 and 5). It
is worth mentioning here that no octane was detected in
these reactions. As expected, no significant differences were
observed between the two diastereoisomeric diphosphites
(S,S)-8 and (R,R)-9 (Table 1, entries 3 and 5).
7
8
11 10
12 10
3.3
91.6
86.9
98.524045.4
4.1
[a] 1-octene (10 mmol), 1-octene/Rh=5000, P(CO/H2)=20 bar, T=808C,
toluene/n-decane (15mL/0.5mL), incubation overnight at 80 8C under
P(CO/H2)=15bar. [b] Conversion: determined by GC using decane as
standard. [c] mol(converted 1-octene)mol(Rh)ꢀ1 hꢀ1
. [d] Isomerised 1-
octene/initial 1-octene. [e] Aldehydes/initial 1-octene. [f] The l:b aldehyde
ratio takes into account branched aldehydes (which consist mainly of 2-
methyloctanal). [g] Exact value not determined because of a very low
amount of branched aldehydes.
trans-2-Octene hydroformylation: Given that the systems de-
scribed above may act as isomerisation catalysts, we decided
to extend our investigations to the hydroformylation of
trans-2-octene, with the expectation that this would produce
appreciable amounts of nonanal. The selective formation of
linear aldehydes starting from internal alkenes is still an im-
portant challenge in industrial hydroformylation. The tests
were carried out at 1208C with the diphosphites 6, 8, 10 and
12 (Table 2), namely with those giving the best regioslectivi-
ties in the hydroformylation of 1-octene. As there, the hy-
droformylation rate of 2-octene decreased with the calixar-
ene ligands with the larger auxiliary groups, while the corre-
sponding regioselectivity increased. The highest l:b ratio,
25.3, was obtained with diphosphite 10, which bears two
CH2–naphthyl groups (Table 2, entry 3). The observation of
such a high regioselectivity implies that at the temperature
of the reaction (1208C), isomerisation of trans-2-octene to
authors, excess of ligand is necessary to prevent the forma-
tion of “naked” rhodium, which behaves as an unselective
catalyst.[24] Changing the pendant auxiliary groups induced
considerable variations in both reactivity and regioselectivi-
ty. As a general trend, larger Z substituents led to lower re-
action rates (Table 1, see, e.g., entries 1 and 6), the highest
turnover frequency (TOF) being found with the propyl-sub-
stituted calixarene 6 (TOF=1440 mol
(olefin)mol(Rh)ꢀ1 hA1).
A
A considerable selectivity increase with respect to 6 (l:b=
58) was observed for the ligands with Z=CH2Ph (8) and
CH2–naphthyl (10), both resulting in a l:b > 100 (Table 1,
entries 1, 3 and 6). Thus, substituents which seemingly in-
crease the metal confinement favour the formation of the
linear aldehyde. However, there is no simple relationship
between the size of the Z group and the selectivity, as can
7148
www.chemeurj.org
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2008, 14, 7144 – 7155

Hydroformylation
FULL PAPER
Table 2. Rhodium-catalysed hydroformylation of trans-2-octene using di-
phosphites 6, 8, 10 and 12.[a]
Table 3. Rhodium-catalysed hydroformylation of styrene using diphos-
phites 6–8 and 10–12.[a]
L
t
Conv[b] TOF[c]
[h] [%]
Product distribution
Isomerisation[d] Aldehydes[e]
l:b[f]
L
L/
Rh H2)
[bar]
P(CO/
t
Conv[b] TOF[c] Branched[b] Linear[b] l:b[d]
[h] [%]
[%]
[%]
[%]
[%]
1
2
3
6
8
10
2
2
2
4
2
8
41.6
30.6
17.3
24.6
25.6
52.1
170
120
70
50
100
50
1.9
1.8
0.7
1.0
2.3
39.7
28.8
16.6
23.6
23.3
46.6
53.2
4.3
1
2
3
6
6
6
10
1
10
20
20
10
518.3
180
220
41.2
61.2
34.8
32.6
8.85
.265
1.4
38.8
1.9
21.7
>25[g]
25.3
5.5
4
24.0
521.7
24 58.7
24.2
5.5 21.4
300
120
0.6
2.0
67.4
4
12
4
5
6
7
8
10
10
10
10
10
4
300 1.95 34.565
5.5
14.7
3.5
2.3
200
320
220
150
23.9
23.2
22.9
23.2
76.1
76.8
77.1
76.8
3.2
3.3
3.4
3.3
24 67.9
20
10 10
4
8
24
4
25.7
35.7
71.4
21.5270
11.3
[a] trans-2-Octene (3.2 mmol), trans-2-octene/Rh=800, L/Rh=10, P(CO/
H2)=20 bar, T=1208C toluene/n-decane (15mL/0.5mL), incubation
overnight at 808C under P(CO/H2)=15bar. [b] Conversion: Determined
by GC using decane as standard. [c] mol(converted trans-2-octene)
mol(Rh)ꢀ1 hꢀ1. [d] Isomerised 2-octene/initial 2-octene. [e] Aldehydes/ini-
tial 2-octene. [f] The l:b aldehyde ratio takes into account all branched al-
dehydes (which consist mainly of 2-methyloctanal). [g] Exact value not
determined because of the very small amount of branched aldehydes.
7
8
11 10
12 10
10
10
78.9
21.1
0.3
1
700
430
390
150
11.3
18.2
23.8
25.2
88.7
81.8
76.2
74.8
7.8
4.5
3.2
3.0
4
34.3
8
63.1
24
70.5
[a] Styrene (10 mmol), styrene/Rh=5000, T=808C, toluene/n-decane
(15mL/0.5mL), incubation overnight at 80 8C under P(CO/H2)=15bar.
[b] Determined by GC using decane as internal standard. [c] mol(con-
verted styrene)mol(Rh)ꢀ1 hꢀ1. [d] l:b aldehyde ratio.
1-octene takes place efficiently. The remarkably high regio-
selectivity observed for 10 slightly surpasses that obtained
with the to date most effective ligand (l:b=24.7) for this re-
action,
van
Leeuwenꢁs
4,5-bis(9-dibenzo
A
proportion of linear aldehyde dramatically increased on re-
placing the propyl groups of 6 (l:b=1.9) by benzyl groups
(ligand 8, l:b=3.2) for reactions at 10 bar. This effect was
also observed with calixarene 10, bearing the somewhat
longer methyl-2-naphtalenyl groups (l:b=3.4). These obser-
vations suggest that with these particular Z substituents, the
shape of the pocket no longer allows the formation of an h3-
complex with styrene, but only that of a conventional s-
alkyl complex involving the terminal carbon atom of the sty-
rene moiety. Note that these high selectivities persisted after
24 h (Table 3, entries 3 and 6). Ligand 12, which is the “de-
butylated” version of 6, also resulted in high proportions of
linear aldehyde, but the selectivity slightly dropped with
time (88.7% linear aldehyde after 1 h vs. 74.8% after 24 h;
Table 3, entry 8), as already seen during the hydroformyla-
tion of octene. Again, no significant differences were ob-
served between the two diastereoisomic diphosphites (S,S)-1
and (R,R)-2 (Table 3, entries 3 and 4). The behaviour of
ligand 11, which is not selective, resembles that of usual
phosphanes (Table 3, entry 7), suggesting again that this
ligand dissociates as the reaction proceeds.
A
angle of 128.98.[26] In comparison, the l:b ratio obtained with
PPh3 in the hydroformylation of trans-2-octene does not
exceed 0.9. Calixarene 12, with no tert-butyl groups on the
upper rim, is the sole ligand for which the l:b ratio de-
creased during catalysis, as already observed when using this
ligand in the hydroformylation of 1-octene (Table 2,
entry 4). This could be a further indication that this ligand
tends to decoordinate with time.
Styrene hydroformylation: It is known that with usual rhodi-
um catalysts (e.g., Rh/PPh3), styrene gives mainly the corre-
sponding branched aldehyde, 2-phenylpropanal.[27] Thus, the
major isomer is the inverse of that observed for alkyl-mono-
substituted olefins. The most plausible explanation for this
regioselectivity is the ready formation of a h3-complex as
shown in Scheme 6.[28]
Styrene hydroaminovinylation: The hydroaminovinylation of
olefins is an atom-economical domino reaction composed of
two steps: 1) hydroformylation of an olefin and 2) in situ
condensation of the resulting aldehyde with a secondary
amine to yield an enamine.[29,30] Surprisingly, this reaction is
not well-developed to date, even though it allows the direct
synthesis of unsaturated products under hydrogenation con-
ditions.[31–34] Encouraged by the performance of 1,3-calixdi-
phosphites in the hydroformylation of styrene, we repeated
this reaction, at 808C, in the presence of dibutylamine or pi-
peridine (Scheme 7). GC analysis revealed the formation of
enamines, aldehydes and amines, the linear regioisomer
being the major product within each category. The propor-
Scheme 6. Hydroformylation of styrene.
Remarkably, for all the ligands tested, except for 11
(Table 3, entry 7), hydroformylation of styrene gave the
linear aldehyde as the major product. Changes in the CO/H2
pressure induced changes in the regioselectivity, but the ac-
tivity was little affected. For example, on decreasing the
pressure from 20 to 10 bar in tests carried out with 6, the se-
lectivity for linear aldehyde rose from 58.8 to 65.2%
(Table 3, entries 1 and 3). The most striking result is that the
Chem. Eur. J. 2008, 14, 7144 – 7155
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
7149

D. Matt, D. SØmeril and L. Toupet
ine regioselectivity was ob-
tained by using diphosphite 12:
82.8% with dibutylamine and
83.4% with piperidine, the pro-
portion of enamine being 69.4
and
83.8%,
respectively
(Table 4, entries 11 and 12).
The fluorenyl ligand 11 pro-
duced high amounts of enamine
(ca. 98%; Table 4, entries 9 and
10), but, as already seen in sty-
rene hydroformylation with this
ligand, the branched product
was the major compound.
Scheme 7. Rhodium-catalysed hydroaminovinylation of styrene.
tion of enamines present was between 51 and 98%
(Table 4). As expected, the proportion of linear product in-
creased in the order aldehyde<enamine<amine, this varia-
tion corresponding to the higher reactivity of the linear
product both in the condensation with the amine and in the
hydrogenation steps (Table 4, entry 4). Increasing the tem-
perature from 808C to 1308C favoured hydrogenation and
consequently led to a lower proportion of enamines. At
higher temperatures, the proportion of linear regioisomer
was comparable for the three types of product (Table 4, en-
tries 2–4). With all the diphosphites tested (6, 8, 10–12), the
proportion of enamines was higher with piperidine than
with dibutylamine, this difference reflecting both an easier
condensation of piperidine with the aldehydes formed and a
more difficult hydrogenation step. The highest linear enam-
Allyl benzyl ether hydroformylation: 1,4-Butanediol is an
important chemical intermediate used industrially as solvent
and for the manufacture of plastics and fibers. A possible
synthesis of this intermediate consists of hydroformylating
an allyl ether. Butanediol is then produced after aldehyde
reduction followed by a deprotection step.[35] In this synthet-
ic route, the key step is the formation of the linear aldehyde
with a high regioselectivity. Considering the excellent regio-
slectivities observed for 1,3-calixdiphosphites in the hydro-
formylation of octenes and styrene, we investigated the
chemo- and regioselective hydroformylation of allyl benzyl
ether. The products formed in this reaction are shown in
Scheme 8.
As previously observed by
Lazzaroni
et al.
using
Table 4. Rhodium-catalysed hydroaminovinylation of styrene using diphosphites 6, 8, 10–12.[a]
[Rh4(CO)12] as catalyst,[36] the
proportion of linear hydrofor-
mylation products increased on
raising the temperature. Thus,
by using 8, the l:b ratio in-
creased from 2.5to 7.4 when
the temperature was brought
from 60 to 1208C (Table 5, en-
tries 2–5). A similar effect was
observed by decreasing the re-
action pressure (Table 5, en-
tries 5, 6 and 9). Interestingly,
the total amount of by-products
(i.e. isomerised and hydrogenat-
ed allyl benzyl ether) did not
change on varying the pressure,
the temperature, or the reaction
L
HNR2
T
[8C]
Conv[b]
[%]
Aldehydes[b]
[%] (l:b)
E-Enamines[b]
[%] (l:b)
Amines[b]
[%] (l:b)
PhEt[b]
[%]
1
2
3
4
5
6
7
8
9
6
6
6
6
8
HNC5H10
HNBu2
HNBu2
HNBu2
HNBu2
HNC5H10
HNBu2
HNC5H10
HNBu2
HNC5H10
HNBu2
HNC5H10
130
130
105
80
130
130
130
130
130
130
130
130
100
100
3.9 (59.8:40.2)
13.0 (76.8:23.2)
13.6 (75.0:25.0)
14.1 (67.4:32.6)
11.8 (67.1:32.9)
3.8 (71.1:28.9)
8.7 (71.9:28.1)
4.9 (78.7:21.3)
traces
80.5 (71.9:28.1)
53.2 (75.8:24.2)
62.5 (76.8:23.2)
63.3 (71.4:28.6)
51.5 (66.0:34.0)
82.5(68.9:31.1)
80.3 (81.0:19.0)
81.9 (79.0:21.0)
97.6 (28.9:71.1)
98.4 (25.3:74.7)
69.4 (82.8:17.2)
83.8 (83.4:16.6)
13.1 (72.3:27.7)
29.2 (75.1:24.9)
19.2 (78.8:21.2)
18.6 (80.4:19.4)
9.4 (67.3:32.7)
8.2 (80.1:19.9)
6.7 (85.3:14.7)
10.7 (92.9:7.1)
traces
2.5
4.6
4.2
1.9
19.9
4.1
3.7
1.9
1.4
1.0
1.0
2.3
99.5
97.9
92.6
98.6
99.4
99.4
99.0
99.4
99.7
99.5
8
10
10
11
11
12
12
10
11
12
traces
7.5 (84.7:15.3)
traces
traces
21.8 (85.5:14.5)
13.4(85.0:15.0)
[a] Styrene (2.0 mmol), amine (2.4 mmol), L/Rh=10, Rh(CO)2(acac) (2 mmol, 0.1 mol%), toluene 30 mL,
P(CO/H2)=8 bar, 24 h, incubation overnight at 808C under P(CO/H2)=10 bar. [b] Determined by GC and
1H NMR spectroscopy.
time (Table 5,
entries 2–9).
Under optimised conditions
(1208C, 10 bar CO/H2), the
linear aldehyde selectivity ob-
served for the various diphos-
phites parallels the trend al-
ready observed in the hydrofor-
mylation of 1-octene, that is,
the l:b increases in the order 6
Scheme 8. Rhodium-catalysed hydroformylation of allyl benzyl ether.
(5.0)<8
(10.0)<10
(15.7)
7150
www.chemeurj.org
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2008, 14, 7144 – 7155

Hydroformylation
FULL PAPER
Table 5. Rhodium-catalysed hydroformylation of allyl benzyl ether using diphosphites 6, 8, 10–12.[a]
phites 6, 8, 10 and 12 gave low
eeꢁs (<18%; Table 6, entries 1–
3 and 10). We noted that the
L
T
[8C]
P(CO/H2)
[bar]
Conv[b]
[%]
Product distribution[b]
Hydrogen. [%]
l:b[c]
Isomer. [%]
Aldehydes [%]
1
2
3
4
5
6
6
8
8
8
8
8
8
8
8
120
60
80
10
20
20
20
20
30
10
10
10
10
10
10
10
100
100
100
100
100
100
957.9
100
100
100
100
100
100
traces
4.9
3.1
2.6
traces
1.9
1.2
8.4
7.3
8.8
11.2
98.8
86.7
89.6
88.6
88.8
86.55
9.9
87.8
88.2
70
5.0 eeꢁs increased on increasing the
2.5
size of the secondary substitu-
ent (propyl<benzyl<methyl-
naphtalenyl). A marked ee in-
3.7
5.7
7.4
100
120
120
120
120
120
120
120
120
120
crease was observed with the
fluorenyl-substituted calixarene
11; the ee here reaching 52%.
In this particular case, the abso-
lute conformation (R) is oppo-
11.6
.3
83
7[d]
8[e]
9
4.1
4.1
8.1
11.8
13.8
20.8
traces
–
10.0
traces
16.2
traces
traces
traces
9.9
15.7
6.5
10
10
11
12
11
12
13
79.2
100
100
19.8 site to the one obtained in all
PPh3
1.6
other tests (Table 6, entry 4).
[a] Allyl benzyl ether (0.8 mmol), L/Rh=10, allyl benzyl ether/Rh=400, toluene 15mL, 24 h, incubation over-
night at 808C under P(CO/H2)=15bar. [b] Conversion determined by 1H NMR spectroscopy. [c] The l:b alde-
hyde ratio takes into account all branched aldehydes, determined by 1H NMR spectroscopy. [d] 2 h. [e] 4 h.
Lowering the temperature to
558C improved the ee to 61%
(Table 6, entry 5). Lower tem-
peratures or operating at lower
pressures led to lower eeꢁs
(Table 6, entries 6–9).
(Table 5, entries 1, 9 and 10). The most chemo- and regiose-
lective tested ligand was the debutylated diphosphite 12, for
which only traces of by-products and a l:b ratio of 19.8 were
observed (Table 5, entry 12). This value compares with those
obtained by Claver with tris-(o-tert-butylphenyl)phos-
phite.[37] For comparison, under similar catalytic conditions
with PPh3 as ligand, an l:b ratio of 1.6 (Table 5, entry 13)
was obtained.
Structure–regioselectivity relationship: Whatever the type of
hydroformylation considered, all the diphosphites 6–10 re-
sulted in remarkably high linear aldehyde regioselectivities.
According to van Leeuwen, regioselectivity correlates essen-
tially with the bite angle of the diphosphane used, rather
than their mode of chelation (axial–axial or equatorial–
axial), in the corresponding catalytic trigonal-bipyramidal
intermediates (Scheme 1). For the ligands of the present
study, the calixarene backbone imposes a separation be-
tween the two phosphorus-bonded oxygen atoms that leads
to ligand bite angles close to 1108. A preliminary study re-
Norbornene asymmetric hydroformylation: All the phos-
phites prepared in this study were optically pure com-
pounds. We therefore assessed some of them, namely those
in which the naphthyl units have an S conformation, in the
asymmetric hydroformylation of norbornene. With only one
exception reported by Huang,[38] rhodium-catalysed hydro-
formylation of norbornene with chiral ligands is known to
give low optical induction (enantiomeric excess (ee) below
25%),[39,40] the major compound being, in general, the exo-
aldehyde. At 808C and under 20 bar of CO/H2, the diphos-
vealed that reaction of [Rh(acac)(8)] with CO/H2 (5bar) led
A
selectively to the [RhH(CO)2(8)] complex, with both phos-
phorus atoms occupying equatorial sites.[41] MM2 calcula-
tions further showed that in such complexes, the rhodium
centre is roughly sandwiched between two symmetrically sit-
uated naphthyl groups (Figure 3, right), thus creating a di-
rectional constraint for the incoming olefin. Note, the two
planes forming the cleft that nests the metal are approxi-
mately parallel, but inclined by about 458 with respect to the
apical axis of the metal centre. The high degree of metal
embrace thus generated by the flat naphthyl substituents
was confirmed by an X-ray diffraction study of the structur-
Table 6. Rhodium-catalysed asymmetric hydroformylation of norbornene
using diphosphites 6, 8, 10–12.[a]
L
T
[8C]
P(CO/H2)
[bar]
Conv[b]
[%]
exo[b]
[%]
endo[b]
[%]
ee(exo)[c]
[%]
ally related complex [Pd
(h3-allyl)(6)]PF6 (P-M-P angle
G
1
2
3
4
5
6
7
8
9
6
80
80
80
80
55
30
80
55
30
80
20
20
20
20
20
20
10
10
10
20
100
100
100
100
100
71.1
100
57.9
35.7
100
99.0
82.7
91.3
100
100
100
100
100
100
1.0
17.3
8.7
traces
–
6 (S)
16 (S)
18 (S)
52 (R)
61 (R)
51 (R)
22 (R)
41 (R)
5 (R)
107.58).[19] The reason why the regioselectivity observed in
octene hydroformylation may be significantly enhanced
upon replacement of the propyl side groups by -CH2Ph or
-CH2–naphthyl groups, that is, on increasing the hemispheri-
cal character of the ligand, is a matter of debate. Possibly
these substituents favourably interact with the apical hydri-
do ligand so as to drive the hydride-transfer step towards a
Rh–n-alkyl intermediate. They may also shape the pocket
about the metal centre and thus favourably orientate the co-
ordinated olefin. In contrast, the presence of fluorenyl
groups (in ligand 11) leads to a loss of selectivity. Clearly, in
this case, the bulkiness of the secondary groups modifies the
8
10
11
11
11
11
11
11
12
–
traces
–
–
10
97.52.5 6 (
S)
[a] Norbornene (0.8 mmol), L/Rh=10, norbornene/Rh=200, toluene
12 mL, 24 h, incubation overnight at 808C under P(CO/H2)=15bar.
[b] Conversion: determined by 1H NMR spectroscopy. [c] Determined by
GC using a chiral column (Chirasil-DEX CB, 25m”0.25mm) after re-
duction into the alcohols.
Chem. Eur. J. 2008, 14, 7144 – 7155
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
7151

D. Matt, D. SØmeril and L. Toupet
shape of the naphthyl clip, which opens slightly (in keeping
with MM2 calculations) as a result of steric interactions with
the calixarene backbone as well as the binaphthyl groups.
Overall, secondary substituents larger than a propyl group
that can sterically interact only with the axial positions ef-
fectively increase the selectivity, while bulkier ones that
induce a widening of the naphthyl pocket lead to a loss of
selectivity. A remarkable result of this study concerns the
hydroformylation of styrene, for which, unexpectedly, un-
usually large amounts of linear aldehyde were formed. The
observed ligand behaviour parallels that obtained with 6–12
in the hydroformylation of octene and therefore suggest a
late transition state for all these reactions. In the case of sty-
rene, the formation of a Rh–allyl intermediate as drawn in
Scheme 6 seems difficult to achieve for steric reasons. Thus,
styrene probably coordinates the metal by forming a con-
ventional p-complex before giving the “linear” alkyl com-
dimensional” metal embrace, can increase the regioselectivi-
ty in hydroformylation with respect to more classical diphos-
phanes having a large bite angle.
Experimental Section
General methods: All syntheses were performed in Schlenk-type flasks
under dry nitrogen. Solvents were dried by conventional methods and
were distilled immediately prior to use. Routine 1H, 13C{1H} and 31P{1H}
NMR spectra were recorded by on a Bruker Avance 300 spectrometer.
1H NMR spectra were referenced to residual protonated solvents (d=
7.16 ppm for C6D6 and 7.26 ppm for CDCl3), 13C chemical shifts are re-
ported relative to deuterated solvents (d=128.0 ppm for C6D6 and
77.16 ppm for CDCl3) and the 31P NMR data are given relative to exter-
nal H3PO4. Elemental analyses were performed by the Service de Micro-
analyse, Institut de Chimie, UniversitØ Louis Pasteur, Strasbourg. The
catalytic solutions were analysed by using a Varian 3900 gas chromato-
graph equipped with a WCOT fused-silica column (25m”0.25mm) or
with a Chirasil-DEX CB column (25m”0.25mm). Calixarenes 1,[43] 2,[43]
3[44] and 5[45] and the chlorophosphites [(R or S)-(1,1’-binaphthalene-2,2’-
diyl)]chlorophosphite[46] were prepared according to literature proce-
dures.
plex [Rh(CO)2(diphosphane)(PhCH2CH2)]. It is worth men-
A
tioning here that the embrace created by the hemispherical
ligands 6–10 in the hydroformylation of styrene is particular-
ly restrictive compared to that reported for other diphos-
phanes, notably Xantphos derivatives, and this may explain
why somewhat higher regioselectivities were obtained with
the former ligands.[10,42]
5,11,17,23-Tetra-tert-butyl-25,27-di-9-fluorenyloxy-26,28-dihydroxyca-
lix[4]arene (4: cone): 9-Bromofluorene (6.000 g, 24.5mmol) was added
to
a suspension of p-tert-butylcalix[4]arene (7.564 g, 11.7 mmol) and
K2CO3 (3.383 g, 24.5mmol) in CH 3CN (150 mL). The reaction mixture
was refluxed for 16 h, then the solvent was evaporated to dryness. The
residue was dissolved in CH2Cl2 (200 mL) and the resulting suspension
was treated with HCl (2n, 200 mL). The aqueous layer was extracted
with CH2Cl2 (2”100 mL). The organic layers were dried over MgSO4,
concentrated and the product was precipitated with methanol. The pre-
cipitate was filtered off and dried under vacuum to afford 4 as a white
Conclusion
In conclusion, the binol-derived calixphosphites 6–10 pro-
vide examples of hemispherical chelators able to efficiently
drive olefin hydroformylation reactions towards the forma-
tion of “linear” products. Our findings hold for octenes (ter-
minal and internal ones), styrene and allyl benzyl ether. The
observed high regioselectivities essentially result from a
combination of large ligand bite angles and the presence of
phosphorus substituents able to form a cleft about the metal
centre, hence creating in the catalytic intermediates the
right structural constraint for the incoming olefin and/or the
apical hydrido ligand. The presence of secondary calixarene
substituents able to sterically interact with the apical posi-
1
3
solid (9.080 g, 80%). H NMR (300 MHz, CDCl3): d=7.69 (d, J=7.5Hz,
4H; CH arom), 7.43 (d, 3J=7.9 Hz, 4H; CH arom), 7.42 (t, 3J=7.6 Hz,
4H; CH arom), 7.14 (t, 3J=7.2 Hz, 4H; CH arom), 7.01 (s, 4H; CH
arom), 6.92 (s, 2H; OH), 6.85(s, 4H; C H arom), 5.96 (s, 2H; OCH), 4.24
and 3.17 (AB system, 2J=13.1 Hz, 8H; ArCH2Ar), 1.26 (s, 18H; C-
A
ACHTREUNG
AHCTREUNG
A
ACHTREUNG
AHCTREUNG
AHCTREUNG
yl-2,2’-dioxyphosphanyloxy)calix[4]arene (6: cone): A suspension of cal-
ixarene 1 (1.760 g, 2.41 mmol) and NaH (60% dispersion in oil, 0.250 g,
6.25mmol) in toluene (40 mL) was heated under reflux for 16 h. [( S)-
(1,1’-Binaphthalene-2,2’-diyl)]chlorophosphite (1.750 g, 5.00 mmol) in tol-
uene (20 mL) was added at 08C and the reaction mixture was stirred for
2 h at room temperature. The crude reaction mixture was filtered through
aluminium oxide. The aluminium oxide was washed with toluene (2”
30 mL). The filtered solution was concentrated to about 5mL. Addition
of hexane (30 mL) gave a precipitate containing 6 and its partial cone
isomer (31P{1H} NMR (121 MHz, C6D6) of partial cone calix: d=133.0 (s)
and 121.2 (s)). The mother liquor was then evaporated to dryness, afford-
ing 6 as pure white powder (1.690 g, 52%); 1H NMR (300 MHz, C6D6):
d=7.69–7.27 (m, 15H; CH arom), 7.18–6.98 (m, 10H; CH arom), 6.95–
6.75(m, 7H; C H arom), 5.10 and 3.52 (AB system, 2J=13.0 Hz, 4H;
tions of bipyramidal [RhH(CO)(olefin)(diphosphane)] inter-
A
mediates can improve the regioselectivity, provided the sub-
stituents remain of moderate bulkiness; too large groups
giving rise to strong steric interactions with the naphthyl
groups and/or the calixarene backbone and therefore open-
ing the cleft that entraps the olefin. The results obtained in
asymmetric norbornene hydroformylation indicate that,
unlike the regioselectivity, enantioselectivity cannot be di-
rectly correlated with a strong metal embrace. Nevertheless,
it must be emphasised that the performance of the fluoren-
yl-substituted ligand 11, giving eeꢁs reaching 61%, is to date
only surpassed by a restricted number of diphosphanes. A
logical extension of this work could consist in introducing
chiral centres in the secondary groups and assessing if this
has an impact on the enantioselectivity. Overall, this study
shows, for the first time, that the use of hemispherical li-
gands, which may be regarded as ligands providing a “three-
2
ArCH2Ar), 5.00 and 3.00 (AB system, J=13.0 Hz, 4H; ArCH2Ar), 4.00–
3.79 (m, 4H; OCH2), 2.06–1.85(m, 4H; C H2CH3), 1.26 (s, 18H; C-
A
N
A
ACHTREUNG
A
ACHTREUNG
AHCTREUNG
7152
www.chemeurj.org
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2008, 14, 7144 – 7155

Hydroformylation
FULL PAPER
A
ACHTREUNG
yl-2,2’-dioxyphosphanyloxy)calix[4]arene (7: cone and 13: partial cone):
A suspension of calixarene 1 (1.760 g, 2.41 mmol) and NaH (60% disper-
sion in oil, 0.250 g, 6.25 mmol) in toluene (40 mL) was heated under
reflux for 16 h. [(R)-(1,1’-Binaphthalene-2,2’diyl)]chlorophosphite
(1.750 g, 5.00 mmol) in toluene (20 mL) was added at 08C and the reac-
tion mixture was stirred for 2 h at room temperature. The crude reaction
mixture was filtered through aluminium oxide. The aluminium oxide was
then washed with toluene (2”30 mL). The filtered solution was then con-
centrated to 5mL and hexane (30 mL) was added precipitating 13
(0.295g, 9%). The mother liquor was then evaporated to dryness, afford-
ing pure 7 as a white powder (2.034 g, 62%).
Cone calixarene 7: 1H NMR (300 MHz, C6D6): d=7.66–7.35(m, 15H;
CH arom), 7.28 (d, 3J=8.8 Hz, 2H; CH arom), 7.14–6.99 (m, 8H; CH
arom), 6.91–6.77 (m, 7H; CH arom), 5.10 and 3.51 (AB system, 2J=
13.0 Hz, 4H; ArCH2Ar), 5.00 and 3.00 (AB system, 2J=12.8 Hz, 4H;
ArCH2Ar), 3.97–3.81 (m, 4H; OCH2), 2.01–1.91 (m, 4H; CH2CH3), 1.26
(s, 18H; C
CH2CH3); 13C{1H} NMR (75MHz, C 6D6): d=154.09–121.98 (arom Cꢁs),
77.34 (s, OCH2), 33.79 (s, (CH3)3), 33.29 (s, ArCH2Ar), 31.95(s,
ArCH2Ar), 31.40 (s, C(CH3)3), 22.96 (s, CH2CH3), 9.43 ppm (s, CH2CH3);
31P{1H} NMR (121 MHz, C6D6): d=133.7 ppm (s, OP
(OAr)2); elemental
A
G
U
ACHTREUNG
AHCTREUNG
G
ACHTREUNG
AHCTREUNG
AHCTREUNG
analysis calcd (%) for C90H90O8P2·1.5toluene (1361.62 +138.21): C 80.48,
H 6.85; found: C 80.52, H 6.97.
1
AHCTREUNG
Partial cone calixarene 13: H NMR (300 MHz, C6D6): d=7.83–7.73 (3H;
bis(1,1’-binaphthyl-2,2’-dioxyphosphanyloxy)calix[4]arene (10: cone): A
suspension of calixarene 3 (0.847 g, 0.91 mmol) and NaH (60% disper-
sion in oil; 0.095g, 2.37 mmol) in toluene (20 mL) was heated under
CH arom), 7.67–7.50 (10H; CH arom), 7.45–6.99 (12H; CH arom), 6.91
(brt, 3J=7.7 Hz, 2H; CH arom), 6.79 (brt, 3J=7.5Hz, 1H; C H arom),
3
3
6.74 (d, J=8.8 Hz, 1H; CH arom), 6.66 (brt, J=7.3 Hz, 2H; CH arom),
4
2
reflux
for
16 h.
[(S)-(1,1’-Binaphthalene-2,2’diyl)]chlorophosphite
6.53 (d, J=2.1 Hz, 1H; m-ArH), 5.13 and 3.42 (AB system, J=12.5Hz,
2H; ArCH2Ar), 4.83 and 2.60 (AB system, 2J=13.0 Hz, 2H; ArCH2Ar),
4.39 and 4.08 (AB system, 2J=14.0 Hz, 2H; ArCH2Ar), 4.02 and 3.31
(AB system, 2J=13.4 Hz, 2H; ArCH2Ar), 3.90–3.69 (3H; OCH2), 3.60–
3.52 (m, 1H; OCH2), 2.12–2.04 (m, 2H; CH2CH3), 1.89–1.82 (m, 2H;
(0.670 g, 1.91 mmol) in toluene (10 mL) was added at 08C and the reac-
tion mixture was stirred for an additional 2 h at room temperature. The
crude reaction mixture was filtered through aluminium oxide. The alumi-
nium oxide was washed with toluene (2”15mL). The filtered solution
and washings were evaporated to dryness under reduced pressure. The
resulting solid was then dissolved in hot hexane. The solution was cooled
at ꢀ168C, yielding microcrystals of 10 (0.652 g, 46% yield) as a white
powder. The mother liquor contained 10 as well as its partial cone isomer
(31P{1H} NMR (121 MHz, C6D6): d=133.7 (s), 119.1 ppm (s)); Compound
10: 1H NMR (300 MHz, C6D6): d=8.06 (s, 2H; CH arom), 7.70 (dd, 3J=
8.4 Hz, 4J=1.3 Hz, 2H; CH arom), 7.55–7.32 (m, 16H; CH arom), 7.23
(d, 3J=8.7 Hz, 2H; CH arom), 7.13–6.85(m, 16H; C H arom), 6.74 (t,
3J=7.8 Hz, 2H; CH arom), 6.70 (d, 4J=2.0 Hz, 2H; m-ArH), 6.65(d,
CH2CH3), 1.70 (s, 9H; C
N
N
A
N
0.70 ppm (t, 3J=7.4 Hz, 3H; CH2CH3); 13C{1H} NMR (75MHz, C 6D6):
d=154.19–121.67 (arom Cꢁs), 76.60 (s, OCH2), 76.35(s, O CH2), 39.25(s,
ArCH2Ar), 36.76 (s, ArCH2Ar), 34.16 (s, C
33.75(s, (CH3)3), 33.07 (s, ArCH2Ar), 32.12 (s, C
ArCH2Ar), 31.51 (s, C(CH3)3), 31.47 (s, C(CH3)3), 31.42 (s, C
23.82 (CH2CH3), 23.69 (CH2CH3), 10.18 (CH2CH3), 9.82 ppm (CH2CH3);
31P{1H} NMR (121 MHz, C6D6): d=133.1 (s, OP
(OAr)2), 121.17 ppm (s,
OP(OAr)2); elemental analysis calcd (%) for C90H90O8P2·0.5C6H14
(1361.62+43.09): C 79.52, H 6.96; found: C 79.51, H 6.97.
(S,S)-5,11,17,23-Tetra-tert-butyl-25,27-dibenzyloxy-26,28-bis(1,1’-binaph-
thyl-2,2’-dioxy-phosphanyloxy)calix[4]arene (8: cone): A suspension of
A
N
C
A
ACHTREUNG
A
N
ACHTREUNG
AHCTREUNG
4
4J=2.2 Hz, 2H; m-ArH), 6.55 (d, J=2.2 Hz, 2H; m-ArH), 5.42 and 5.00
ACHTREUNG
(AB system, 2J=11.9 Hz, 4H; OCH2), 5.21 and 3.12 (AB system, 2J=
13.0 Hz, 4H; ArCH2Ar), 5.13 and 2.71 (AB system, 2J=13.0 Hz, 4H;
ACHTREUNG
ArCH2Ar), 1.25(s, 18H; C
NMR (75MHz, C 6D6): d=152.22–121.34 (arom Cꢁs), 77.96 (s, OCH2),
33.76 (s, C(CH3)3), 33.61 (s, C(CH3)3), 33.49 (s, ArCH2Ar), 31.75(s,
ArCH2Ar), 31.44 (s, C(CH3)3), 31.09 ppm (s, C
(CH3)3); 31P{1H} NMR
(121 MHz, C6D6): d=122.0 ppm (s, OP(OAr)2); elemental analysis calcd
(%) for C106H94O8P2 (1557.86): C 81.72, H 6.08; found: C 81.63, H 6.13.
(S,S)-5,11,17,23-Tetra-tert-butyl-25,27-di-9-fluorenyloxy-26,28-bis(1,1’-bi-
A
G
ACHTREUNG
calixarene 2 (2.000 g, 2.41 mmol) and NaH (60% dispersion in oil;
0.250 g, 6.25 mmol) in toluene (40 mL) was heated under reflux for 16 h.
[(S)-(1,1’-Binaphthalene-2,2’-diyl)]chlorophosphite (1.750 g, 5.00 mmol)
in toluene (20 mL) was added at 08C and the reaction mixture was
stirred for 2 h at room temperature. The crude reaction mixture was fil-
tered through aluminium oxide. The aluminium oxide was then washed
with toluene (2”30 mL). The filtered solution was concentrated to about
5mL. Addition of hexane (30 mL) gave a precipitate containing 8 and its
partial cone isomer (31P{1H} NMR (121 MHz, C6D6) of the partial cone
isomer: d=133.5(s), 120.3 ppm (s)). Pure 8 was obtained by evaporation
of the mother liquor (1.970 g, 56%); 1H NMR (300 MHz, C6D6): d=
7.69–7.34 (m, 20H; CH arom), 7.23–6.76 (m, 16H; CH arom, m-ArH),
6.71 (d, 4J=2.4 Hz, 4H; m-ArH), 6.57 (d, 4J=2.4 Hz, 2H; m-ArH), 5.39
and 4.93 (AB system, 2J=11.8 Hz, 4H; CH2Ph), 5.08 and 3.17 (AB
system, 2J=11.8 Hz, 4H; ArCH2Ar), 5.08 and 2.66 (AB system, 2J=
A
ACHTREUNG
A
ACHTREUNG
AHCTREUNG
AHCTREUNG
naphthyl-2,2’-dioxyphosphanyloxy)calix[4]arene (11: cone and 14: partial
cone): A suspension of calixarene 4 (2.350 g, 2.41 mmol) and NaH (60%
dispersion in oil; 0.250 g, 6.25 mmol) in toluene (40 mL) was heated
under reflux for 16 h. [(S)-(1,1’-Binaphthalene-2,2’diyl)]chlorophosphite
(1.750 g, 5.00 mmol) in toluene (20 mL) was added at 08C and the reac-
tion mixture was stirred for 2 h at room temperature. The crude reaction
mixture was filtered through aluminium oxide and the aluminium layer
was washed with toluene (2”30 mL). The filtered solution and washings
were concentrated to about 5mL. Addition of petroleum ether (50 mL)
afforded crystals of 14 (partial cone) (0.350 g, 9%). The mother liquor
was then evaporated to dryness. The residue was treated with hot
hexane. The thus obtained suspension was filtered through a glass fritt,
then evaporated to dryness, yielding pure 11 (cone) (0.530 g, 14%)
11.8 Hz, 4H; ArCH2Ar), 1.30 (s, 18H; C
(CH3)3); 13C{1H} NMR (75MHz, C 6D6): d=151.94–121.43 (arom Cꢁs),
77.66 (s, OCH2), 33.78 (s, (CH3)3), 33.61 (s, (CH3)3), 33.54 (s,
ArCH2Ar), 31.78 (s, ArCH2Ar), 31.47 (s, C(CH3)3), 31.12 ppm (s, C-
(CH3)3); 31P{1H} NMR (121 MHz, C6D6): d=123.6 ppm (s, OP
(OAr)2);
A
ACHTREUNG
C
A
C
ACHTREUNG
AHCTREUNG
A
N
Cone calixarene 11: 1H NMR (300 MHz, C6D6): d=8.76 (d, 3J=7.5Hz,
2H; CH arom), 7.65–7.60 (m, 4H; CH arom), 7.55–7.46 (m, 10H; CH
arom), 7.24 (d, 3J=8.6 Hz, 2H; CH arom), 7.16–6.99 (m, 12H; CH
elemental analysis calcd (%) for C98H90O8P2·toluene (1457.71+92.14): C
81.37, H 6.37; found: C 81.70, H 6.73.
Chem. Eur. J. 2008, 14, 7144 – 7155
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
7153

D. Matt, D. SØmeril and L. Toupet
arom), 6.87 (t, 3J=7.5Hz, 2H; C H arom), 6.80–6.69 (m, 6H; CH arom),
6.61 (t, 3J=7.7 Hz, 2H; CH arom), 6.50 (d, 3J=7.5Hz, 2H; C H arom),
6.41 (brs, 4H; CH arom), 6.17–6.14 (m, 4H; CH arom and OCH), 5.68
ArH), 6.29 (d, 4J=2.0 Hz, 2H; m-ArH), 6.23 (d, 4J=2.0 Hz, 2H; m-
2
ArH), 5.69 and 5.02 (AB syste, J=11.9 Hzm, 4H; CH2Ph), 5.22 and 3.00
2
2
(AB system, J=13.0 Hz, 4H; ArCH2Ar), 5.22 and 2.81 (AB system, J=
13.0 Hz, 4H; ArCH2Ar), 4.56 (s, 1H; CH-acac), 1.03 (s, 18H; C(CH3)3),
0.76 (s, 18H; C
(CH3)3), 0.30 ppm (s, 6H; CH3-acaa); 13C{1H} NMR
and 3.32 (AB system, 2J=12.6 Hz, 4H; ArCH2Ar), 5.04 and 2.55 (AB
ACHTREUNG
2
AHCTREUNG
system, J=13.2 Hz, 4H; ArCH2Ar), 1.12 (s, 18H; C
A
18H; C
Cꢁs), 84.20 (s, OCH), 33.76 (s, C
ArCH2Ar), 32.92 (s, ArCH2Ar), 31.24 (s, C
(CH3)3); 31P{1H} NMR (121 MHz, C6D6): d=118.7 ppm (s, OP
(CH3)3); 13C{1H} NMR (75MHz, C 6D6): d=151.51–119.42 (arom
(CH3)3), 33.61 (s, C(CH3)3), 33.37 (s,
(CH3)3), 31.19 ppm (s, C-
(OAr)2);
(75MHz, CDCl 3): d=183.16 (s, CO-acac), 152.23–120.00 (arom Cꢁs),
97.99 (s, CH-acac), 77.79 (s, OCH2), 33.60 (s, ArCH2Ar), 33.59 (s, C-
A
ACHTREUNG
A
G
A
AHCTREUNG
AHCTREUNG
N
ACHTREUNG
A
ACHTREUNG
elemental analysis calcd (%) for C110H94O8P2 (1605.90): C 82.27, H 5.90;
found: C 82.24, H 5.71.
Partial cone calixarene 14: 1H NMR (300 MHz, C6D6): d=8.42 (d, 3J=
1682.57 [M+Na]+, 1659.59 [M]+, 1559.54 [MꢀC5H7O2]+ expected isotop-
ic profiles; elemental analysis calcd (%) for C103H97O10P2Rh: C 74.54, H
5.89; found: C 74.61, H 5.88.
7.4 Hz, 1H; CH arom), 7.74–6.73 (m, 1H; CH arom), 6.63–6.58 (m, 2H;
3
AHCTREUNG
CH arom), 6.48 (brs, 2H; CH arom), 6.39 (d, J=8.8 Hz, 1H; CH arom),
6.30 (d, 3J=7.5Hz, 1H; C H arom), 5.98 (s, 1H; OCH), 5.68 (s, 1H;
OCH), 5.32 and 3.21 (AB system, 2J=12.4 Hz, 2H; ArCH2Ar), 4.77 and
2.45(AB system, 2J=13.4 Hz, 2H; ArCH2Ar), 4.00 and 3.42 (AB system,
2J=13.7 Hz, 2H; ArCH2Ar), 3.95and 3.21 (AB system, 2J=13.9 Hz, 2H;
AHCTREUNG
scribed above for 15, but starting from ligand 11. Yield: 70%; IR (KBr):
n˜ =1517, 1579 cmꢀ1 (acac); 1H NMR (300 MHz, CDCl3): d=9.47 (d 3J=
7.6 Hz„ 2H; CH arom), 7.82 (d, 3J=7.4 Hz, 2H; CH arom), 7.66 (d, 3J=
ArCH2Ar), 1.41 (s, 9H; C
(CH3)3), 1.14 ppm (s, 9H; C
152.16–119.37 (arom Cꢁs), 83.50 (s, OCH), 82.26 (s, OCH), 39.21 (s,
ArCH2Ar), 36.90 (s, ArCH2Ar), 34.13 (s, C(CH3)3), 33.90 (s, C(CH3)3),
33.80 (s, C(CH3)3), 33.57 (s, C(CH3)3), 32.74 (s, ArCH2Ar), 32.34 (s,
ArCH2Ar), 31.86 (s, C(CH3)3), 31.83 (s, C(CH3)3), 31.57 (s, C(CH3)3),
31.20 ppm (s, C
(CH3)3); 31P{1H} NMR (121 MHz, C6D6): d=133.4 (s, OP-
(OAr)2), 119.46 ppm (s, OP(OAr)2); elemental analysis calcd (%) for
110H94O8P2·toluene (1605.90+92.14): C 82.76, H 6.05; found: C 82.84, H
A
N
3
7.5Hz, 4H; C H arom), 7.59–7.51 (m, 6H; CH arom), 7.44 (d, J=8.9 Hz,
A
ACHTREUNG
2H; CH arom), 7.29–6.91 (m, 22H; CH arom), 6.53 (d, 4J=2.1 Hz, 2H;
m-ArH), 6.45(d, 4J=2.1 Hz, 2H; m-ArH), 6.24 (d, 4J=2.2 Hz, 2H; m-
ArH), 6.21 (d, 3J=7.6 Hz, 2H; CH arom), 6.06 (s, 2H; OCH), 5.89 (d,
3J=8.8 Hz, 2H; CH arom), 5.86 and 3.75 (AB system, 2J=12.3 Hz, 4H;
ArCH2Ar), 4.97 and 2.46 (AB system, 2J=13.4 Hz, 4H; ArCH2Ar), 4.47
A
ACHTREUNG
A
ACHTREUNG
A
N
ACHTREUNG
ACHTREUNG
(s, 1H; CH-acac), 1.01 (s, 18H; C
G
E
A
ACHTREUNG
0.20 ppm (s, 6H; CH3-acac); 13C{1H} NMR (75MHz, CDCl 3): d=182.39
(s, CO-acac), 152.00–119.16 (arom Cꢁs), 97.35 (s, CH-acac), 84.68 (s,
C
5.88. Crystals (colourless) of 14 suitable for X-ray diffraction were ob-
tained by slow diffusion of petroleum ether into a solution of a mixture
of 11 and 14 in toluene (see above, preparation of 14).
OCH), 34.28 (s, ArCH2Ar), 33.83 (s, C
(s, C(CH3)3), 31.20 (s, C
(CH3)3), 24.65ppm (s, CH3-acac); 31P{1H} NMR
(121 MHz, CDCl3): d=126.1 ppm (d, J(P,Rh)=326.7 Hz, OP(OAr)2); MS
(CH3)3), 33.64 (s, ArCH2Ar), 31.24
G
ACHTREUNG
E
ACHTREUNG
(S,S)-25,27-Dipropyloxy-26,28-bis(1,1’-binaphthyl-2,2’-dioxyphosphany-
(ESI TOF): m/z: 1806.59 [M]+, 1707.55 [MꢀC5H7O2]+ expected isotopic
profiles; elemental analysis calcd (%) for C115H101O10P2Rh: C 76.40, H
5.63; found: C 76.23, H 5.63.
loxy)calix[4]arene (12: cone): A suspension of calixarene 5 (1.220 g,
2.41 mmol) and NaH (60% dispersion in oil; 0.250 g, 6.25 mmol) in tolu-
ene (40 mL) was heated under reflux for 16 h. [(S)-(1,1’-Binaphthalene-
2,2’diyl)]chlorophosphite (1.750 g, 5.00 mmol) in toluene (20 mL) was
added at 08C and the reaction mixture was stirred for 2 h at room tem-
perature. The crude reaction mixture was filtered through aluminium
oxide. The aluminium layer was washed with toluene (2”30 mL). The fil-
tered solution and the washings were concentrated to about 5mL and pe-
troleum ether was added (50 mL). After 3 days, colourless crystals of
pure 12 were collected (0.580 g, 21%). As revealed by NMR spectrosco-
py, the mother liquor contained several other products which were not
isolated. 1H NMR (300 MHz, C6D6): d=7.63–7.37 (m, 18H; CH arom),
7.29 (d, 3J=8.7 Hz, 2H; CH arom), 6.89 (t, 3J=7.6 Hz, 2H; CH arom),
6.81 (d, 3J=8.1 Hz, 4H; CH arom), 6.37–6.61 (m, 8H; CH arom), 6.46
(d, 3J=7.1 Hz, 2H; CH arom), 5.03 and 3.44 (AB system, 2J=13.6 Hz,
4H; ArCH2Ar), 4.91 and 2.97 (AB system, 2J=13.6 Hz, 4H; ArCH2Ar),
3.83–3.67 (m, 4H; OCH2), 1.84–1.64 (m, 4H; CH2CH3), 0.38 ppm (t, 3J=
7.3 Hz, 6H; CH2CH3); 13C{1H} NMR (75MHz, C 6D6): d=156.87–121.92
(arom Cꢁs), 77.03 (s, OCH2), 32.66 (s, ArCH2Ar), 31.43 (s, ArCH2Ar),
22.97 (s, CH2CH3), 9.57 ppm(s, CH2CH3); 31P{1H} NMR (121 MHz,
Crystal structure of 12·toluene: Mr =1229.28, orthorhombic, P21, a=
11.857(2), b=15.103(2), c=34.846(4) Š, V=6240.1(2) Š3, Z=4, 1calcd
=
1.308 mgmꢀ3, m=1.32 cmꢀ1, F
(000)=1796, T=120(1) K. Data were col-
E
lected on a Oxford Diffraction Xcalibur Saphir 3 diffractometer (graphite
MoKa radiation, l=0.71073 Š). The structure was solved with SIR-97,[47]
which revealed the non-hydrogen atoms of the molecule. After anisotrop-
ic refinement, many hydrogen atoms were found with a Fourier differ-
ence analysis. The whole structure was refined with SHELX-97[48] and
full-matrix least-square techniques (use of F2; x, y, z, bij for P, C and O
atoms, x, y, z in riding mode for H atoms); 820 variables and 5070 obser-
vations with I>2.0s(I); calcd w=1/[s2(Fo2)+(0.039P)2] in which P=
(F2o +2Fc2)/3. R1=0.070, wR2=0.0127, Sw=0.740, D1<0.56 eŠꢀ3, Flack
parameter=ꢀ0.02(2).
Crystal structure of 14·toluene: Mr =1697.93, monoclinic, space group
P21, a=11.9307(7), b=14.7771(7), c=26.7373(9) Š, b=91.178(3)8, V=
4712.8(4) Š3, Z=4, 1calcd =1.197 mgmꢀ3, m=1.06 cmꢀ1, F(000)=1796, T=
110(1) K. Data were collected on a Oxford Diffraction Xcalibur Saphir 3
diffractometer (graphite MoKa radiation, l=0.71073 Š). The structure
was solved with SIR-97,[47] which revealed the non-hydrogen atoms of the
molecule. After anisotropic refinement, many hydrogen atoms were
found with a Fourier difference analysis. The whole structure was refined
with SHELX-97[48] and full-matrix least-square techniques (use of F2; x,
y, z, bij for P, C and O atoms, x, y, z in riding mode for H atoms); 1144
variables and 10357 observations with I>2.0s(I); calcd w=1/[s2(Fo2)+
(0.023P)2] in which P=(Fo2 +2Fc2)/3. R1=0.041, wR2=0.063, Sw=0.731,
D1<0.25eŠ ꢀ3, Flack parameter=0.00(6).
C6D6): d=134.4 ppm (s, OP
ACHTREUNG
C74H58O8P2·1.5toluene (1137.22 +138.20):
C
H
C
79.65, H 5.62. Crystals of cone-12 (colourless) suitable for X-ray diffrac-
tion were obtained by slow diffusion of petroleum ether into the reaction
mixture after filtration over aluminium oxide.
ACHTREUNG
AHCTREUNG
(5mL) was added to a solution of 8 (0.500 g, 0.34 mmol) in CH2Cl2
(250 mL). The resulting solution turned from green to yellow within a
few minutes. After 16 h, the solvent was evaporated to dryness. The
yellow solid which was washed with cold hexane (ꢀ788C) to afford 15
(0.427 g, (75%). IR (KBr): n˜ =1518, 1578 cmꢀ1 (acac); 1H NMR
(300 MHz, CDCl3): d=7.95(d, 3J=6.5Hz, 4H; C H arom), 7.72 (d, 3J=
CCDC-622309 (12·toluene) and CCDC- 609569 (14·toluene) contain the
supplementary crystallographic data for this paper. These data can be ob-
tained free of charge from The Cambridge Crystallographic Data Centre
via www.ccdc.cam.ac.uk/data_request/cif.
General procedure for the hydroformylation experiments: The hydrofor-
mylation experiments were carried out in a glass-lined, 100 mL stainless
steel autoclave containing a magnetic stirring bar. In a typical run, the
3
8.1 Hz, 2H; CH arom), 7.63 (d, J=8.1 Hz, 2H; CH arom), 7.57–7.49 (m,
4H; CH arom), 7.39 (d, 3J=8.9 Hz, 2H; CH arom), 7.33–6.99 (m, 20H;
4
4
CH arom), 6.82 (d, J=2.2 Hz, 2H; m-ArH), 6.49 (d, J=2.1 Hz, 2H; m-
autoclave was charged under nitrogen with of a solution of [Rh-
7154
www.chemeurj.org
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2008, 14, 7144 – 7155

Hydroformylation
FULL PAPER
A
[20] P. C. J. Kamer, P. W. N. M. van Leeuwen, J. N. H. Reek, Acc. Chem.
Res. 2001, 34, 895–904.
[21] Z. Freixa, P. W. N. M. van Leeuwen, Dalton Trans. 2003, 1890–1901.
[22] C. Jaime, J. de Mendoza, P. Prados, P. M. Nieto, C. Sꢃnchez, J. Org.
Chem. 1991, 56, 3372–3376.
[23] SPARTAN, Version 1.1.8, Wawefunction, Irvine (USA), 1997.
[24] C. J. Cobley, D. D. Ellis, A. G. Orpen, P. G. Pringle, J. Chem. Soc.
Dalton Trans. 2000, 1109–1112.
[25] C. Kunze, D. Selent, I. Neda, R. Schmutzler, A. Spannenberg, A.
Bçrner, Heteroat. Chem. 2001, 12, 577–585.
ligand in toluene (10 mL) and toluene (4.5mL). Once closed, the auto-
clave was flushed twice with syngas (CO/H2 1:1 v/v), pressurised with a
CO/H2 mixture and heated. After 16 h, the autoclave was depressurised,
olefin and, if necessary, internal standard (decane) were added to the re-
action mixture. The autoclave was then heated and pressurised. The
progress of the reaction was checked by monitoring the pressure de-
crease. During the experiments, several samples were taken and analysed
by GC or H NMR spectroscopy.
[26] R. P. J. Bronger, P. C. J. Kamer, P. W. N. M. van Leeuwen, Organo-
metallics 2003, 22, 5358–5369.
[27] C. K. Brown, G. Wilkinson, J. Chem. Soc. A 1970, 2753–2764.
[28] C. Claver, P. W. N. M. van Leeuwen, in Rhodium-Catalysed Hydro-
formylation (Eds.: P. W. N. M. van Leeuwen, C. Claver), Kluwer,
Dordrecht, 2000, pp. 107–144.
[29] P. Eilbracht, L. Bꢄrfacker, C. Buss, C. Hollman, B. E. Kitsos-Rzy-
chon, C. L. Kranemann, T. Rische, R. Roggenbuck, A. Schmidt,
Chem. Rev. 1999, 99, 3329–3365.
Acknowledgement
This work was supported by the Agence Nationale de la Recherche
(WATERCAT Program). We thank Dr. C. Jeunesse for helpful discus-
sions.
[30] P. Eilbracht, A. M. Schmidt, Top. Organomet. Chem. 2006, 18, 65 –
95.
[31] Y. Dong, C. A. Basacca, J. Org. Chem. 1997, 62, 6464–6465.
[32] Y.-S. Lin, B. E. Ali, H. Alper, J. Am. Chem. Soc. 2001, 123, 7719–
7720.
[33] M. Ahmed, A. M. Seayad, R. Jackstell, M. Beller, Angew. Chem.
2003, 115, 5773–5777; Angew. Chem. Int. Ed. 2003, 42, 5615–5619.
[34] E. Teuma, M. Loy, C. Le Berre, M. Etienne, J.-C. Daran, P. Kalck,
Organometallics 2003, 22, 5261–5267.
[35] W. E. Smith, G. R. Chambers, R. C. Lindberg, J. N. Cawse, A. J.
Dennis, G. E. Harrison, D. R. Bryant, Catal. Org. React. 1985, 22,
151–167.
[36] R. Lazzaroni, R. Settambolo, G. Uccello-Barretta, Organometallics
1995, 14, 4644–4650.
[37] N. Ruiz, A. Polo, S. Castillꢂn, C. Claver, J. Mol. Catal. A 1999, 137,
93–100.
[38] J. Huang, E. Bunel, A. Allgeier, J. Tedrow, T. Storz, J. Preston, T.
Correll, D. Manley, T. Soukup, R. Jensen, R. Syed, G. Moniz, R.
Larsen, M. Martinelli, P. J. Reider, Tetrahedron Lett. 2005, 46, 7831–
7834.
[39] G. Consiglio, F. Rama, J. Mol. Catal. 1991, 66, 1–5 .
[40] S. Lu, X. Li, A. Wang, Catal. Today 2000, 63, 531–536.
[41] W. Oberhauser, D. SØmeril, D. Matt, unpublished results.
[42] C. B. Dieleman, P. C. J. Kamer, J. N. H. Reek, L. A. van der Veen,
Helv. Chim. Acta 2001, 84, 3269–3280.
[43] K. Iwamoto, K. Arabi, S. Shinkai, Tetrahedron 1991, 47, 4325–4342.
[44] I. I. Stoikov, A. A. Khrustalev, I. S. Antipin, A. I. Konovalov, Dokl.
Akad. Nauk 2000, 374, 202–205.
[45] A. Arduini, M. Fabbi, M. Montovani, L. Mirone, A. Pochini, A.
Secchi, R. Ungaro, J. Org. Chem. 1995, 60, 1454–1457.
[46] N. Cramer, S. Laschat, A. Baro, Organometallics 2006, 25, 2284–
2291.
[47] “SIR97, an integrated package of computer programs for the solu-
tion and refinement of crystal structures using single crystal data”:
A. Altomare, M. C. Burla, M. Camalli, G. Cascarano, C. Giacovaz-
zo, A. Guagliardi, A. G. G. Moliterni, G. Polidori, R. Spagna, J.
Appl. Crystallogr. 1998, 31, 74–77.
[1] Rhodium Catalysed Hydroformylation (Eds.: P. W. N. M. van Leeu-
wen, C. Claver), Kluwer, Dordrecht, 2000.
[2] Aqueous-Phase Organometallic Catalysis (Eds.: B. Cornils, W. A.
Herrmann), Wiley-VCH, Weinheim, 2004.
[3] E. Monflier, in Multiphase Homogeneous Catalysis, Vol. 1 (Eds.: B.
Cornils, W. A. Herrmann, I. T. Horvath, W. Leitner, S. Mecking, H.
Olivier-Bourbigou, D. Vogt), Wiley-VCH, Weinheim 2005, pp. 179–
183.
[4] R. Tudor, M. Ashley, Platinum Met. Rev. 2007, 51, 164–171.
[5] W. Ahlers, M. Rçper, P. Hofmann, D. C. M. Warth, R. Paciello, WO
01/58589 (BASF), 2001.
[6] J. R. Briggs, G. T. Whiteker, Chem. Commun. 2001, 2174–2175.
[7] C. P. Casey, G. T. Whiteker, M. G. Melville, L. M. Petrovich, J. A.
Gavney Jr. , D. R. Powell, J. Am. Chem. Soc. 1992, 114, 5535–5543.
[8] L. A. van der Veen, P. C. J. Kamer, P. W. N. M. van Leeuwen,
Angew. Chem. 1999, 111, 349–351; Angew. Chem. Int. Ed. 1999, 38,
336–338.
[9] R. Paciello, L. Siggel, M. Rçper, Angew. Chem. 1999, 111, 2045–
2048; Angew. Chem. Int. Ed. 1999, 38, 1920–1923.
[10] L. A. van der Veen, P. H. Keeven, G. C. Schoemaker, J. N. H. Reek,
P. C. J. Kamer, P. W. N. M. van Leeuwen, M. Lutz, A. L. Spek, Orga-
nometallics 2000, 19, 872–883.
[11] P. W. N. M. van Leeuwen, P. C. J. Kamer, J. N. H. Reek, P. Dierkes,
Chem. Rev. 2000, 100, 2741–2769.
[12] M. R. Eberhard, K. M. Heslop, A. G. Orpen, P. G. Pringle, Organo-
metallics 2005, 24, 335–337.
[13] Z. Csꢂk, G. Szalontai, G. Czira, L. Kollꢃr, J. Organomet. Chem.
1998, 570, 23–29.
[14] S. Steyer, C. Jeunesse, D. Armspach, D. Matt, J. Harrowfield, in Cal-
ixarenes 2001 (Eds.: Z. Asfari, V. Bçhmer, J. Harrowfield, J. Vicens),
Kluwer, Dordrecht, 2001, pp. 513–535.
[15] D. Armspach, I. Bagatin, E. Engeldinger, C. Jeunesse, J. Harrow-
field, M. Lejeune, D. Matt, J. Iran. Chem. Soc. 2004, 1, 10–19.
[16] P. Kuhn, C. Jeunesse, D. SØmeril, D. Matt, P. Lutz, R. Welter, Eur. J.
Inorg. Chem. 2004, 4602–4607.
[17] C. Kunze, D. Selent, I. Neda, M. Freytag, P. G. Jones, R. Schmutzler,
W. Baumann, A. Bçrner, Z. Anorg. Allg. Chem. 2002, 628, 779–787.
[18] C. Jeunesse, C. Dieleman, S. Steyer, D. Matt, J. Chem. Soc. Dalton
Trans. 2001, 881–892.
[48] G. M. Sheldrick, SHELXL-97, Program for Crystal Structure Re-
finement, University of Gçttingen, Gçttingen (Germany), 1997.
[19] D. SØmeril, C. Jeunesse, D. Matt, L. Toupet, Angew. Chem. 2006,
118, 5942–5946; Angew. Chem. Int. Ed. 2006, 45, 5810–5814.
Received: April 18, 2008
Chem. Eur. J. 2008, 14, 7144 – 7155
ꢀ 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
7155