A new diphosphite promoting highly regioselective rhodium-catalyzed hydroformylation

Article abstract of DOI:10.1021/om2000508

A new rhodium catalyst is described that gives 99% regioselectivity in linear aldehyde in the hydroformylation of internal and terminal olefins. High-pressure NMR spectroscopic data verify an energetically preferred bis-equatorial mode of coordination for the bidentate phosphite ligand in the hydride resting state of the catalyst. Experimental FTIR spectra are compared with the individual spectra of the e,e and e,a isomers of [HRh(CO) ₂(P∩P)] calculated from density functional theory.

Full text of DOI:10.1021/om2000508

ARTICLE
pubs.acs.org/Organometallics
A New Diphosphite Promoting Highly Regioselective
Rhodium-Catalyzed Hydroformylation†
Detlef Selent,*,‡ Robert Franke,§ Christoph Kubis,‡ Anke Spannenberg,‡ Wolfgang Baumann,‡
Burkard Kreidler,§ and Armin B€orner*,‡
‡Leibniz-Institut f€ur Katalyse e. V. an der Universit€at Rostock, Albert-Einstein-Strasse 29a, D-18059 Rostock, Germany
§Evonik Oxeno GmbH, Paul-Baumann-Strasse 1, D-45772 Marl, Germany
S Supporting Information
b
ABSTRACT: A new rhodium catalyst is described that gives
99% regioselectivity in linear aldehyde in the hydroformylation
of internal and terminal olefins. High-pressure NMR spectro-
scopic data verify an energetically preferred bis-equatorial mode
of coordination for the bidentate phosphite ligand in the hydride
resting state of the catalyst. Experimental FTIR spectra are
compared with the individual spectra of the e,e and e,a iso-
mers of [HRh(CO)2(P∩P)] calculated from density functional
theory.
he rhodium-catalyzed hydroformylation of olefins to give
aldehydes is an important and widely investigated homo-
preference for the a,e-[HRh(CO)2(P1∩P2)] complex isomer has
been confirmed by high-pressure NMR spectroscopy.11
Here we will present evidence that very high regioselectivity in
both terminal and internal olefin hydroformylation can be
achieved when 1,3,2-dioxaphospholane moieties based on a
sterically highly demanding substituted 1,2-ethanediol, such as
benzpinacol, are part of the ligand structure. Apart from the
excellent catalytic performance, the new motif is accessible in a
two-step synthesis and has therefore the potential for industrial
application.
T
geneously catalyzed reaction.1 With a terminal olefin used as a
substrate, a high molar fraction of n-aldehyde is usually desired.
This goal can be achieved by choosing rhodium complexes
containing rigid bidentate phosphorus ligands which show
reduced conformational flexibility. These ligands include dipho-
sphites based on sterically demanding bisphenols.2 Despite the
fact that a large number of diols and (di)phenol derivatives have
been used to form diphosphites,3 the BIPHEPHOS ligand (see
Chart 1) is still the most prominent member among them,
bearing two seven-membered phosphacycles.4 With this ligand
98ꢀ99% n-selectivity is usually seen in terminal olefin hydro-
formylation. Another advantage is its short and rather cheap
synthesis. In contrast, monophosphites induce less regioselec-
tivity, which is usually accompanied by a pronounced substrate
double-bond isomerization; the occurrence of this parallel reac-
tion during hydroformylation has been concluded early from the
formation of unexpected iso-aldehydes from long-chain olefins.5,6
Such activity of the catalyst can be of benefit for the production
of terminal aldehydes via an isomerizationꢀhydroformylation
reaction sequence from internal alkenes, as was shown with
rhodium catalysts modified with fluoroalkyl phosphites, dipho-
sphines, and phosphonites.7 Excellent selectivities to the corre-
sponding n-aldehydes from 2-alkenes have recently been
obtained with a new, structurally less defined rhodium tetrapho-
sphorus ligand catalyst.8 With our synthesis of bidentate O-acyl
phosphites predominant n-regioselective catalysts became avail-
able, showing very high turnover frequencies (>4000 hꢀ1) for the
hydroformylation of internal alkenes.9,10 For these catalysts, the
’ RESULTS AND DISCUSSION
First, the new ligand building block 2-chloro-4,40,5,50-tetra-
phenyl-1,3,2-dioxaphosphole (1) was synthesized, which was
easily accessible in nearly quantitative yield from the reaction
of benzpinacol with PCl3 in the presence of triethylamine or N,
N0-dimethylaminobutane in toluene. For details of analyses and
the X-ray molecular structure of this compound, see the Support-
ing Information.
The synthesis of the unsymmetrical ligand 2 involves the
reaction of the monolithium salt of 2,20-dihydroxy-3,30-di-tert-
butyl-5,50-dimethoxybiphenyl with 1 followed by treatment of
the hydroxy phosphite intermediate obtained with 2-chloro-
1,3,2-benzodioxaphosphorin-4-one in the presence of triethyla-
mine (Scheme 1). Two diastereomers are formed, which are
characterized by phosphorus NMR signals centered at 117.0
Received: January 20, 2011
Published: August 15, 2011
r
2011 American Chemical Society
4509
dx.doi.org/10.1021/om2000508 Organometallics 2011, 30, 4509–4514
|

Organometallics
ARTICLE
(d, JPP = 50.4 Hz), 144.9 ppm (d, JPP = 50.4 Hz) and 118.3 (d,
JPP = 51.4 Hz) and 145.3 ppm (d, JPP = 51.4 Hz), respectively,
and pronounced spin coupling between the different phosphorus
atoms that we interpret in terms of a through-space interaction.12
For the synthesis of the diphosphites 3 and 4 2 equiv of the
phosphorus chloride 1 was reacted with racemic 1,10-bi(2-
naphthol) or 2,20-dihydroxy-3,30-di-tert-butyl-5,50-dimethoxybi-
phenyl, respectively, leading to an approximately 80% yield after
recrystallization. In the 31P NMR spectrum, both compounds
exhibit single resonances at 140.5 (3) and 145.3 ppm (4).
The new ligands were tested in the rhodium-catalyzed hydro-
formylation of 1-octene and of internal octenes and 2-pentene
(Scheme 2). The reaction temperature was set to 120 °C for
the internal olefinic substrates to favor olefin isomerization. A
comparison with BIPHEPHOS (5) is given (see Table 1). It is
noteworthy that under the conditions used in this study full
chemoselectivity was achieved for all batches.
The diphosphites 2 and 3 form an active rhodium catalyst but
do not induce outstanding regioselectivity with 1-octene used as
the substrate. For the unsymmetrical 2, which does contain an
anhydridic O-acyl moiety derived from salicylic acid, this is in
accord with earlier results obtained for a similar ligand structure.9
An enhanced reaction rate in the presence of this ligand is reflected
in the highest aldehyde yield obtained from internal octenes and
2-pentene, respectively, where themain product isthe correspond-
ing n-aldehyde (ratio linear:branched 3.2 and 3.9).
Scheme 2. Parallel and Consecutive Isomerization and
Hydroformylation Reactions of 2-Pentene
Significantly higher n:iso product aldehyde ratios were ob-
tained with 4, even in comparison to the industrial standard
BIPHEPHOS. Thus, this ratio is 124 (Rh-5: 70.4) from 1-octene
and 99 (Rh-5: 22) from 2-pentene. The reduced reactivity
toward 2-pentene under the standard conditions is obvious
and was confirmed by additional experiments. Thus, a doubled
concentration of the Rh-4 catalyst together with a prolonged
reaction time of 24 h was needed to enhance the yield of hexanals
from 14% to 63%. This was accompanied by a small drop in n-
selectivity from 99.0 to 97.5%. When the ligand 4 to Rh ratio was
increased from 2 to 5, no effect on hexanal yield and regioselec-
tivity could be observed.
Interestingly, the Rh-5 catalyst from the literature worked
similarly with the different internal olefins. Thus, 93.3% n-
nonanal from the octene mixture and 95.8% n-hexanal from
2-pentene were obtained. This points to a similar balanced
kinetic control between olefin isomerization and terminal and
internal hydroformylation for both substrates. With Rh-4, the
selectivity obtained from the octenes is only ∼70% but a higher
aldehyde yield was obtained compared to 2-pentene with the
first-order rate constant kobs = 1.8 ꢁ 10ꢀ3 minꢀ1. A time-
dependent plot of the molar fractions of the octane isomers
shows that after an initial period of 50 min with ongoing hydro-
formylation the ratio of the individual isomers remains constant
(see Figure 1). The 0.01 fraction determined for 1-octene fits to
the thermodynamic equilibrium value.13 The fraction of 2-octene
(cis + trans) is depleted to 0.38 (equilibrium: 0.45), whereas the
3- and 4-octenes are populated to 0.36 (0.32) and 0.24 (0.22).
2-Octene, therefore, is more reactive in hydroformylation than
the other internal isomers and isomerization is not fast enough
to equilibrate the octenes. Consequently, the initial change of
olefin composition is accompanied by a decrease of n-nonanal
selectivity.
Chart 1. Ligands Used in This Study: New Diphosphites 2ꢀ4
and 5 (BIPHEPHOS)
Hydroformylation of 2-pentene proceeds with the first-order
rate constant kobs = 7.2 ꢁ 10ꢀ4 minꢀ1. The composition of the
substrate mixture changes continuously with the less reactive
trans isomer, accumulating to a 0.78 mol fraction after 4 h.14
This is significantly above the equilibrium value of 0.69 (see
Scheme 1. Ligand Synthesis, Exemplified for the Unsymmetrical Diphosphite 2
4510
dx.doi.org/10.1021/om2000508 |Organometallics 2011, 30, 4509–4514

Organometallics
ARTICLE
Table 1. Hydroformylationa of 1-Octene,b n-Octenes,c,d, and
hydroformylation, is required, as has been exemplified for the
n-dodecene isomers.18
2-Pentenec
The formation of the most efficient hydroformylation catalyst,
Rh-4, was studied by high-pressure NMR spectroscopy under
conditions comparable to those for the catalytic batch routine.
Thus, the catalyst precursor [acacRh(CO)2] was treated with 4
in toluene-d8 under an argon atmosphere and the resulting
solution was then transferred to a modified 10 mm high-pressure
sapphire NMR tube. With the sample placed inside the magnet, a
mixture of CO and H2 (1:1) was supplied to the reaction solution
via capillary at a constant head space pressure of 20 bar. This
was done for the whole time of the experiment to ensure gas
saturation. After heating to 70 °C, the reaction mixture equili-
brated within 30 min.
The spectroscopic data obtained confirm the clean formation
of the rhodium hydride [HRh(CO)2(4)] (see Scheme 3) to-
gether with equimolar amounts of acetylacetone. The hydrido
complex is characterized by a proton resonance at ꢀ10.00 ppm
(d, JHRh = 3.4 Hz) and a broadened phosphorus signal at 166.1
ppm (d, JPRh= 235 Hz). The lack of any observable HꢀP
coupling and the equivalency of both phosphorus nuclei point
to a preference for e,e coordination of the diphosphite, with the
hydride located in an axial position. The spectrum of the hydride
remained unchanged upon cooling to room temperature and
depressurization. IR measurement of the syngas-saturated NMR
sample resulted in bands at ν~(CO) 1985 (w), 2012 (vs) and 2065
(vs) cmꢀ1 (trace A in Figure 4), equal to that observed during
hydroformylation. This agrees with the observation of equivalent
phosphorus atoms by NMR spectroscopy, since two absorptions
around 2020 and 2070 cmꢀ1 are indicative of the bis-equatorial
ligand coordination.19 The resonance at 1985 cmꢀ1 can be
assigned to e,a-[HRh(CO)2(4)]. It is noteworthy that NMR
spectroscopy cannot differentiate between the two hydride iso-
mers at ambient temperature, although the broadened phos-
phorus signal might be due to the respective rotational dynamics.
In order to confirm these results, we also performed quantum
chemical DFT calculations for each of the isomeric e,a and e,e
rhodium hydride complexes (see Figure 3 for e,e- and e,a-[HRh-
(CO)2(4)]). These calculations verify a stabilization by 4 kJ/mol
for the latter isomer at 298 K, which predominates with a content
of 80% in the isomer mixture at room temperature. For the calcu-
lated structures, see Figure 3. With an PꢀRhꢀP angle of 120.7°
the e,e isomer approaches the idealized tbp geometry.
In Figure 4 the overlapping experimental FTIR spectrum is
compared with the theoretical spectra obtained for the individual
rhodium hydride complexes. The calculation shows that all
absorptions of the HRh(CO)2 fragments within the range from
1900 to 2100 cmꢀ1 arise from a simultaneous excitation of
RhꢀH and CO stretching vibrations. Despite some frequency
shift, the calculated spectra fit relatively well to the experiment
with strong absorptions at 2010 and 2054 cmꢀ1 and the relative
band intensities obtained for the e,e and the band for the e,a
isomer located at 1981 cmꢀ1. The weak absorptions at 2004 and
2019 cmꢀ1 calculated for the latter isomer are not resolved
experimentally, owing to overlap and the relatively low molar
fraction of this complex.
Isolable rhodium complexes of ligand 4 have been easily
obtained at room temperature in toluene by substitution of
the neutral ligands from [(acac)Rh(CO)2] and [(η3-C3H5)Rh-
(COD-1.5)] with 1 equiv of diphosphite to yield [(acac)-
Rh(4)]21 and [(η3-C3H5)Rh(4)], respectively. The solution
NMR spectroscopic data of the latter complex are consistent with
yield of nonanal (%)/
yield of hexanal (%)/
n-selectivity (%)
n-selectivity (%)
2-pentenef
ligand
1-octene
n-octenese
2
3
4
5
87/92.9
93/87.5
90/99.2
92/98.6
88/76.2
28/72.2
39/69.8
50/93.3
98/79.8
83/63.6
14/99.0g
83/95.8
a Conditions: solvent toluene, ligand to rhodium ratio 2, t = 4 h.
b Conditions: T = 100 °C, p = 50 bar, precursor [acacRh(CO)2],
[Rh] = 0.3 ꢁ 10ꢀ3 M. c Conditions: T = 120 °C, p = 20 bar (con-
stant), [Rh] = 0.75 ꢁ 10ꢀ3 M. d A technical internal octene mixture
was used; see the Supporting Information. e [octenes] = 1.62 M.
f [2-pentene] = 2.35 M. g The same result was obtained with a ratio
4/Rh= 5.
Figure 1. Isomerization/hydroformylation of internal octenes with the
Rh-4 catalyst: time-resolved plot of molar fractions of octenes (left;
initial fraction of 1-octene was 0.03) and C9 aldehyde isomers (right).
For the reaction conditions, see Table 1.
Figure 2).13 Similar to the the case for the octenes, the terminal
isomer constantly levels at 0.01 (equilibrium: 0.03). The time-
resolved in situ FTIR spectra taken during the reaction prove
the stability of the catalyst and the presence of [HRh(CO)2(4)]
as the only resting state over the full reaction period, a result
which was also verified for the hydroformylation of internal
octenes.
The low 1-pentene concentration observed during catalysis,
together with the high product regioselectivity obtained, proves
that the n-aldehyde is formed in a consecutive reaction. The
major reaction pathway includes cis-2-pentene, which is de-
populated. Furthermore, the high regioselectivity observed
points to a strong tendency of the isopentyl intermediates to
hydride elimination and 1-pentene complex formation.15,16
Such a double-bond shift could proceed even faster with the
octenes, because a chain length dependency in olefin isomer-
ization has recently been rationalized for rhodium diphosphine
catalysts.17 The lower regioselectivity obtained with the inter-
nal octene hydroformylation needs further explanation, and a
detailed kinetic analysis of both reactions, isomerization and
4511
dx.doi.org/10.1021/om2000508 |Organometallics 2011, 30, 4509–4514

Organometallics
ARTICLE
Figure 2. Isomerization/hydroformylation of (E)-/(Z)-2-pentene with the Rh-4 catalyst. (left) Yield versus time of hexanal (ꢁ100%) and profiles of
molar fractions of 2-pentenes (main axis) and of 1-pentene (secondary axis). The final mole fraction of cis-2-pentene is 0.21 (equilibrium: 0.28); for
further details see text). (right) In situ FTIR spectra of the metal carbonyl region (alterations of the baseline from 1925 to 1975 cmꢀ1 are due to
background subtraction). Reaction conditions: T = 120 °C, p = 20 bar (CO:H2 = 1:1), t = 4 h, solvent toluene.
Scheme 3. Formation of e,e-[HRh(CO)2(4)]
Figure 4. FTIR absorption spectra: (A) room-temperature experimental
spectrum of [HRh(CO)2(4)] (CaF2, 0.1 mm) after toluene-d8 solvent
spectrum subtraction; (B, C) spectra from DFT theoretical calculations
(298 K) of e,e-[HRh(CO)2(4)] (B) and e,a-[HRh(CO)2(4)] (C).20
2
2JPP = 58.5 Hz) and 169.1 ppm (dd, JPRh = 320.1 Hz, JPP
=
58.5 Hz). The coupling constants JPRh are considerably higher
than those measured for corresponding rhodium complexes with
bidentate phosphines (169ꢀ200 Hz) and are in the same range of
the values of 317 and 304 Hz found for the allyl-type diphosphite
complex syn-[(η3-2,4-dimethylpentadienyl)Rh(pinacop)].23,24
In the molecular structure (Figure 5) a distorted-planar
coordination at rhodium can be observed, with the allyl group
occupying two cis positions at the rhodium atom and with a mean
deviation of 0.08 Å from the best plane through Rh, P1, P2, C1,
and C3. The P1ꢀRh1ꢀP2 angle is 104.49(2)°, which points to
the flexibility of the ligand as compared with the angle of 120.7°
calculated for e,e-[HRh(CO)2(4)] and is just midway between
the ideal values of 120° for bis-equatorial (e,e) and 90 °C for
equatorialꢀaxial (e,a) diphosphite coordination in tbp-struc-
tured hydrides [HRh(CO)2(P∩P)].25 In contrast, the reduced
steric demand present in the bis(triphenyl phosphite) complex
(η3-C3H5)Rh[P(OPh)3]2 results in a PꢀRhꢀP angle of 97.55°
and shorter PꢀRh bonds.26 The structure of [(η3-C3H5)Rh(4)]
Figure 3. Structures from DFT calculations20 of (left) e,e- and (right) e,
a-[HRh(CO)2(4)]. The angles PꢀRhꢀP are 120.7° for the e,e and
110.3° for the e,a isomer. RhꢀP bond lengths for the e,e isomer are
respectively 2.33 and 2.29 Å and for the e,a isomer are 2.34 Å (a-P) and
2.37 Å (e-P).
a rigid and unsymmetrical η3 bonding mode of the allyl ligand.
Each of the allyl Hsyn and Hanti protons is separately detectable, as
in [(η3-2-Me-C3H5)Rh(arphos)].22 Resonances centered at 1.97
(t, 3JHP = 11.7 Hz; Ha1), 2.53 (dd, 3JHP = 13.1 Hz, 3JHP = 9.9 Hz;
Ha2), 3.08 (m, Hs1), 3.79 (m, Hs2) and 4.69 ppm (m, Hm) are
observed. Due to slow intermolecular movement, including
hindered allyl group rotation, an extra data set is observed not
only for the substructures of the ligand backbone but also the
phosphorus atoms, which resonate at 166.4 (dd, JPRh = 326.0 Hz,
4512
dx.doi.org/10.1021/om2000508 |Organometallics 2011, 30, 4509–4514

Organometallics
ARTICLE
Figure 5. Molecular structure of [(η3-C3H5)Rh(4)]. Thermal ellipsoids represent 30% probability. Hydrogen atoms are omitted. Selected geometric
data: P1ꢀRh1 = 2.2016(6) Å, P2ꢀRh1 = 2.2039(6) Å, P1ꢀRh1ꢀP2 = 104.49(2)°, C1ꢀRh1 = 2.176(2) Å, C3ꢀRh1 = 2.177(2) Å, C1ꢀC2AꢀC3 =
115.5(3)°.
also proves the capability of the phosphorus ligand of providing a
pocketlike environment for the rhodium center. Such a crowded
ligand arrangement has been discussed to be essential for the
relatively high n:iso product ratio of 46 that is observed in the
propene hydroformylation promoted by (S,R,S)-6,60-(CH3)2-
BIPHEPHOS.27
GmbH) and Dr. B. Hannebauer (AQura GmbH, Evonik In-
dustries) regarding FTIR spectroscopy and DFT quantum
chemical calculations is gratefully acknowledged.
’ DEDICATION
†Dedicated to Professor Rudolf Taube on the occasion of his
80th birthday.
’ CONCLUSION
A benzpinacol substructure was included into a bisphosphite
ligand used in Rh-catalyzed hydroformylation. This motif re-
duces the activity of the catalyst toward the undesired hydro-
formylation of internal olefins. As a consequence, with 1-octene
an outstandingly high l:b aldehyde ratio of 124 is achieved.
Remarkable regioselectivity is also obtained in the consecutive
isomerizationꢀhydroformylation of 2-pentene. Regioselectivity
and activity are significantly influenced by the chain length of the
olefinic substrate. The spectroscopic and theoretical results
obtained for the Rh-4 catalytic system are in accord with previous
experience that, for highly regioselective catalysts, bis-equatorial
diphosphite coordination is typical for the resting state of the
catalyst. Due to the straightforward synthesis of the new ligand, it
has the potential of broad application in academic and industrial
hydroformylation. The first evidence was already given by
Haumann and Wasserscheid, who used the ligand in supported
ionic liquid phase (SILP) catalysis for the highly selective
hydroformylation of mixed C4 feedstocks.28
’ REFERENCES
(1) (a) Rhodium Catalyzed Hydroformylation; van Leeuwen, P. W.
N. M., Claver, C., Eds.; Kluwer: Dordrecht, The Netherlands, 2000.
(b) Protzmann, G.; Wiese, K.-D. Erd€ol, Erdgas, Kohle 2001, 117, 235-
240. (c) Wiese, K.-D., Obst, D. Hydroformylation. In Catalytic Carbo-
nylation Reactions; Beller, M., Ed.; Springer: Heidelberg, Germany, 2008;
Topics in Organometallic Chemistry 18, p 1.
(2) Billig, E.; Abatjoglou, A. G.; Bryant, D. R. US 4668651, 1987 and
US 4769498, 1988 (UCC).
(3) Urata, H.; Itagaki, H.; Takahashi, E.; Wada, Y.; Tanaka, Y.;
Ogino, Y. U.S. Patent 5 910 600, 1997 (Mitsubishi Chem. Corp.).
(4) (a) Cuny, G. D.; Buchwald, S. L. J. Am. Chem. Soc. 1993,
115, 2066. (b) Moasser, B.; Gladfelter, W. L.; Roe, D. C. Organometallics
1995, 14, 3832. (c) van Rooy, A.; Kamer, P. C. J.; van Leeuwen, P. W. N.
M. J. Organomet. Chem. 1997, 201. (d) Rush, S. N.; Noskov, Y. G.; Kron,
T. E.; Korneeva, G. A. Kinet. Catal. 2009, 557.
(5) (a) van Rooy, A.; De Bruijn, J. N. H.; Roobeek, K. F.; Kamer,
P. C. J.; van Leeuwen, P. W. N. M. J. Organomet. Chem. 1996, 507, 69.
(b) van Rooy, A.; Kamer, P. C. J.; van Leeuwen, P. W. N. M.; Goubitz, K.;
Fraanje, J.; Veldman, N.; Spek, A. L. Organometallics 1996, 15, 835.
(6) (a) Asinger, F.; Berg, O. Chem. Ber. 1955, 88, 445. (b) Keulemans,
A.J. M.;Kwantes, A.; vanBavel, T. Recl. Trav. Chim. Pays-Bas1948, 67, 298.
(7) (a) van Leeuwen, P. W. N. M.; Roobeek, K. F. Brit. Patent
2 068 377, 1980 (Shell). (b) van der Veen, L. A.; Kamer, P. C. J.; van
Leeuwen, P. W. N. M. Angew. Chem., Int. Ed. 1999, 38, 336. (c) van der Veen,
L. A.; Kamer, P. C. J.; van Leeuwen, P. W. N. M. Organometallics 1999,
18, 4765. (d) Klein, H.; Jackstell, R.; Wiese, K.-D.; Borgmann, C.; Beller, M.
Angew. Chem., Int. Ed. 2001, 40, 3408. (e) Selent, D.; Wiese, K.-D.; R€ottger,
D.; B€orner, A. Angew. Chem., Int. Ed. 2000, 39, 1639. (f) Seayad, A.; Ahmed,
M.; Klein, H.; Jackstell, R.; Gross, T.; Beller, M. Science 2002, 297, 1676.
(8) (a) Yan, Y.;Zhang, X.;Zhang, X.J. Am. Chem. Soc. 2006, 128, 16058.
(b) Yu, S.; Chie, Y.; Guan, Z.; Zhang, X. Org. Lett. 2008, 10, 3469.
(9) Selent, D.; Hess, D.; Wiese, K.-D.; R€ottger, D.; Kunze, C.;
B€orner, A. Angew. Chem., Int. Ed. 2001, 40, 1696.
(10) An enhanced olefin isomerization rate due to the reduced σ-
donor character of the O-acyl phosphite moiety is probable. A similar
effect was observed earlier in olefin hydrogenation with catalysts
containing less donating ligands: Schrock, R. R.; Osborn, J. A. J. Am.
Chem. Soc. 1976, 98, 2134.
(11) Selent, D.; Wiese, K.-D.; Bo€rner, A. In Catalysis of Organic
Reactions; Sowa, J. R., Ed.; Taylor & Francis: Boca Raton, FL, 2005; Vol.
20, p 459.
’ ASSOCIATED CONTENT
S
Supporting Information. Text, tables, figures, and CIF
b
files giving experimental procedures, compound characterization
data, crystallographic data for compounds 1 and [(η3-C3H5)Rh-
(4)], details on DFT quantum calculations, and an overlap of the
experimental structure with the quantum chemically calculated
structure of [η3-C3H5Rh(4)]. This material is available free of
charge via the Internet at http://pubs.acs.org.
’ AUTHOR INFORMATION
Corresponding Authors
*D.S.: tel, ++49-381-1281169; fax, ++49-381-128151169; e-mail,
detlef.selent@catalysis.de. A.B.: email, armin.boerner@catalysis.de.
’ ACKNOWLEDGMENT
We appreciate financial support from Evonik Oxeno GmbH,
Marl, Germany. Support from Dr. D. Hess (Evonik Oxeno
4513
dx.doi.org/10.1021/om2000508 |Organometallics 2011, 30, 4509–4514

Organometallics
ARTICLE
(12) (a) Diz, A. C.; Contreras, R. H.; Natiello, M. A.; Gavarini, H. O.
J. Comput. Chem. 1985, 6, 647. (b) Perera, D.; Shaw, B. L.; Thornton-Pett,
M.; Vessey, J. D. Inorg. Chim. Acta 1993, 175. (c) Hierso, J.-C.; Fihri, A.;
Ivanov, V. V.;Hanquet, B.; Pirio, N.; Donnadieu, B.; Rebiꢀere, B.; Amardeil,
R.; Meunier, P. J. Am. Chem. Soc. 2004, 126, 11077. (d) Hierso, J.-C.;
Evrard, D.; Lucas, D.; Richard, P.; Cattey, H.; Hanquet, B.; Meunier, P.
J. Organomet. Chem. 2008, 693, 574.
(13) Alberty, R. A.; Gehrig, C. A. J. Phys. Chem. Ref. Data 1985,
14, 803.
(14) This is similar to the reactivity of unsaturated fatty acid
derivates: Muilwijk, K. F.; Kamer, P. C. J.; van Leeuwen, P. W. N. M.
J. Am. Oil Chem. Soc. 1997, 74, 223.
(15) Casey, C. P.; Petrovich, L. M. J. Am. Chem. Soc. 1995, 117, 6007.
(16) With rhodium, it is accepted that olefin isomerization takes
place via the hydride migrationꢀelimination route, which can occur
parallel to hydroformylation, leading to isomerized substrate in the
reaction mixture: Cramer, R. J. Am. Chem. Soc. 1966, 88, 2272. Stefani,
A.; Consiglio, G.; Botteghi, C.; Pino, P. J. Am. Chem. Soc. 1977, 99, 1058.
ꢀ
(17) Carvajal, M. A.; Kozuch, S.; Shaik, S. Organometallics 2009,
28, 3656.
(18) (a)Cornely, W. Ph.D. Thesis, RWTHAachen, Aachen, Germany,
1979. (b) Cornely, W.; Fell, B. Chem. Z. 1981, 105, 317. Frankel, E. N.
J. Am. Oil Chem. Soc. 1971, 48, 248.
(19) (a) van Rooy, A.; Kamer, P. C. J.; van Leeuwen, P. W. N. M.;
Goubitz, K.; Fraanje, J.; Veldman, N.; Spek, A. L. Organometallics 1996,
15, 835. (b) Buisman, G. J. H.; van der Veen, L. A.; Klootwijk, A.;
de Lange, W. G. J.; Kamer, P. C. J.; van Leeuwen, P. W. N. M.; Vogt, D.
Organometallics 1997, 16, 2929. (c) Castellanos-Pꢁaez, A.; Castillꢁon, S.;
Claver, C.; van Leeuwen, P. W. N. M.; de Lange, W. G. J. Organometallics
1998, 17, 2543. (d) Buisman, G. J. H.; van der Veen, L. A.; Kamer,
P. C. J.; van Leeuwen, P. W. N. M. Organometallics 1997, 16, 5681.
(e) Buisman, G. J. H; Vos, E. J.; Kamer, P. C. J.; van Leeuwen, P. W. N. M.
J. Chem. Soc., Dalton Trans. 1995, 409.
(20) The DFT calculations were performed with the TURBO-
MOLE suite of programs using the functional BP86 employing the
RI-J approximation and, for all atoms except Rh, a valence double-ζ basis
including one set of polarization functions (SVP). The basis set for Rh
was a slightly modified valence basis set together with an effective core
potential replacing 28 core electrons up to 3d. For more details see the
Supporting Information.
(21) For details of synthesis and characterization, see the Supporting
Information.
(22) Fryzuk, M. Inorg. Chem. 1982, 21, 2134.
(23) Manger, M.; Wolf, J.; Teichert, M.; Stalke, D.; Werner, H.
Organometallics 1998, 17, 3210.
(24) Bleeke, J. R.; Donaldson, A. J.; Peng, W.-J. Organometallics
1988, 7, 33.
(25) For a graphical overlap of the X-ray and calculated structures of
[(η3-C3H5)Rh(4)] as well as details of DFT quantum chemical calcula-
tions, see the Supporting Information.
(26) John, K. D.; Salazar, K. V.; Baker, R. T.; Sattelberger, A. P.
Private communication to the Cambridge Structural Database, deposi-
tion number CCDC 147142, 2001.
(27) Briggs, J. R.; Whiteker, G. T. Chem. Commun. 2001, 2174.
(28) Jakuttis, M.; Sch€onweiz, A.; Werner, S.; Franke, R.; Wiese,
K. D.; Haumann, M.; Wasserscheid, P. Angew. Chem., Int. Ed. 2011, 50,
4492.
4514
dx.doi.org/10.1021/om2000508 |Organometallics 2011, 30, 4509–4514