Synthesis of novel rhodium phosphite catalysts for efficient and selective isomerization-hydroformylation reactions

Article abstract of DOI:10.1016/j.jorganchem.2009.11.007

New modular H₈-BINOL-based phosphite ligands have been synthesized. High activity and regioselectivity has been achieved in the rhodium-catalyzed isomerization-hydroformylation of internal olefins. The active catalysts have been characterized by in situ NMR studies.

Full text of DOI:10.1016/j.jorganchem.2009.11.007

Journal of Organometallic Chemistry 695 (2010) 479–486
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Communication
Synthesis of novel rhodium phosphite catalysts for efficient and selective
isomerization–hydroformylation reactions
Irene Piras a, Reiko Jennerjahn a, Ralf Jackstell a, Wolfgang Baumann a, Anke Spannenberg a,
Robert Franke b, Klaus-Diether Wiese b, Matthias Beller a,
*
a Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Strasse 29 A, 18059 Rostock, Germany
b OXENO Olefinchemie GmbH, Marl, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 12 May 2009
Received in revised form 30 October 2009
Accepted 8 November 2009
Available online 18 November 2009
New modular H8-BINOL-based phosphite ligands have been synthesized. High activity and regioselectiv-
ity has been achieved in the rhodium-catalyzed isomerization–hydroformylation of internal olefins. The
active catalysts have been characterized by in situ NMR studies.
Ó 2009 Elsevier B.V. All rights reserved.
Keywords:
Homogeneous catalysis
Isomerization
Hydroformylation
Bisphosphites
Rhodium
1. Introduction
needs to be highly selective towards the linear aldehyde (Scheme
1, step c).
Hydroformylation of olefins constitutes one of the most impor-
tant homogeneously catalyzed processes in industry, which covers
an annual production of almost ten million tons of aliphatic alde-
hydes [1]. Although hydroformylation reactions are widely applied
in natural product synthesis [2] and organic synthesis [3], there
still exists a significant academic and industrial interest to develop
more active and selective catalysts for such transformations [4].
From an economical point of view one of the most important goals
in current hydroformylation research is the selective conversion of
internal olefins to linear aldehydes (Scheme 1) [5].
This domino reaction sequence offers the opportunity to use
cheaper mixtures of internal and terminal olefins as feedstock for
bulk chemicals and to save time and energy, which is needed for
the additional purification steps [6]. In order to obtain the industri-
ally desired linear aldehydes from internal olefins, the catalyst sys-
tem needs to actively isomerize internal olefins (Scheme 1, step a).
Notably, the thermodynamic mixture, even of low molecular
weight olefins e.g. butenes, contains less than 5% of the terminal
olefin. Hence, hydroformylation of the terminal olefin must occur
at much faster rate, typically a factor 10–100, compared to the
hydroformylation of the different internal olefins (Scheme 1, step
b versus step c). Moreover, hydroformylation of the terminal olefin
Major advancements have been made toward this goal in the
last decade. Particularly, efforts have been spent on the design
and synthesis of new ligands. Notable examples constitute the bis-
phosphite ligands of UCC [7] and Dupont/DSM [8], Xantphos li-
gands by van Leuween and co-workers [9], acylphosphite and
phosphonite ligands by Börner and co-workers [10] or substituted
Naphos ligands, that were introduced by us [11]. Recently, also
efficient pyrrole-based tetraphosphorous ligands were developed
by Zhang and co-workers [12]. In addition, regioselective isomeri-
zation–hydroformylation sequences of internal olefins have been
reported in a biphasic system with water-soluble sulfonated Na-
phos derivatives [13]. Among the various ligand types for isomer-
ization–hydroformylation reactions, bulky bisphosphites are
probably the most versatile class of ligands [7,14]. In general, phos-
phite ligands are attractive because they are easily prepared from
inexpensive PCl3 and alcohols. Moreover, they are less sensitive
to air and other oxidizing agents than phosphines.
2. Results and discussion
Herein, we report the synthesis of new modular H8-BINOL-
based phosphite ligands that display excellent activity in the
hydroformylation of internal and terminal olefins with high selec-
tivities for the linear aldehydes.
* Corresponding author. Fax: +49 381 1281 5000.
E-mail address: matthias.beller@catalysis.de (M. Beller).
0022-328X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2009.11.007

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I. Piras et al. / Journal of Organometallic Chemistry 695 (2010) 479–486
the hydride signal in the 1H NMR spectra (Fig. 2b and c). The 1H-
Rh
b
(
)
CHO
decoupled 31P NMR spectra displays a typical Rh–P coupling con-
stant (1J (Rh,P) = 240 Hz) of a rhodium-hydride complex with trigo-
nal-bipyramidal structure. The hydridorhodium complex shows a
small P–H coupling constant (2J (P,H) = 8.4 Hz) indicative of a bis-
equatorial (ee) coordination mode [18]. Further evidence for the
bisequatorial complex is provided by IR measurements owing to
two absorption bands for carbonyl vibrations around 1993 and
2017 cmꢀ1, which are characteristic for ee isomers [21].
R
R
R
+
CO/H2
R
CHO
a
(
)
CHO
Rh
c
(
)
R
R
R
CHO
R
+
CO/H2
Scheme 1. Isomerization–hydroformylation reactions: From internal olefins to
Next, we investigated the catalytic potential of the novel bis-
phosphite ligands in comparison with known highly active ligands
9 [10] and BIPHEPHOS 10 (Fig. 3) [7,22], and the unsubstituted H8-
Binaphthol-based ligand 11 [23]. Ligand 11 has been prepared
starting from racemic binaphthol.
Therefore, ligands 3–6 were tested in the rhodium-catalyzed
hydroformylation of different internal and terminal olefins. The ac-
tive catalysts were prepared in situ by adding an appropriate
amount of bisphosphite ligand to [Rh(acac)(CO)2]. All reactions
were carried out in THF with isooctane as internal standard. Ini-
tially, the effects of ligand/metal ratio, temperature, and pressure
on the regioselectivity were studied using 2-pentene as substrate.
linear aldehydes.
Recently, we developed an improved route for the synthesis of
octahydrogenated 3,30-dibromo-substituted binaphthols [15].
Applying this three step sequence a variety of novel binaphthol
derivatives is accessible on multi-g scale. Based on their availabil-
ity we had the idea to apply these building blocks for novel bis-
phosphite ligands depicted in Fig. 1.
While monodentate ligands based on the dibromo-substituted
H8-BINOL skeleton are well known [16], no bisphosphites bearing
at least two substituted H8-BINOL skeletons have been described
so far. Nevertheless, the synthesis of selected ligands [17] proceeds
straightforward in four steps from commercially available
2,20-binaphthol 1a [18]. After hydrogenation with Pd/C and regio-
selective bromination of octahydrobinaphthol the resulting 3,30-di-
bromooctahydro-2,20-binaphthol was treated with phosphortri
chloride to give the corresponding chlorophosphite 2. Subsequent
treatment of partially hydrogenated and non-hydrogenated
binaphthol derivatives 1a–c with two equivalents of 2 in the pres-
ence of triethylamine and a catalytic amount of 4-dimethylamino-
pyridine (DMAP) gave ligands 3–5 (Scheme 2).
We applied 2-pentene as
a benchmark for internal olefins,
especially for the commercially important 2-butene. As expected
without any ligand only low activity (TOF = 179) and low regiose-
lectivity (n/iso = 41:59) are observed (Table 1, entry 1). On the
other hand adding 3 high yield (85%) and excellent regioselectivity
(n/iso = 90:10) are obtained under similar conditions (Table 1, en-
try 6). As shown in Table 1 a ligand/metal ratio of 2 is sufficient to
achieve high regioselectivity. Applying a higher ligand/metal ratio
the reaction rate decreased but the regioselectivity did not im-
prove (Table 1, entry 2). This is an important advantage compared
to most known hydroformylation catalysts based on bisphosphites,
for which a larger excess of ligand is required. In agreement with
other known catalysts the CO/H2 pressure influences both the reg-
ioselectivity as well as the reaction rate (Table 1, entry 4–6)). At
high pressure (50 bar) the reaction rate and linear selectivity were
lower compared to 10–20 bar synthesis gas pressure. Among the
different biphosphites, ligands 3 and 5 gave remarkably high linear
to branched aldehyde ratios with the highest reaction rate (Table 1,
entries 6 and 9). With respect to n-selectivity and activity, they
outperform known ligands 9 and 10. Ligand 11 shows a linear/
branched ratio of 41:59 (Table 1, entry 13). It seems that the
ortho-substitutions in the H8-Binol unit are crucial to achieve high
n-selectivity.
In order to compare the ligands more appropriately, hydro-
formylations of 1-pentene, 1-octene and 2-octene were performed
as typical benchmark reactions (Table 2). Again, without any added
ligand typical non-selective hydroformylations are observed (Table
2, entries 1, 8, 13). In case of 1-pentene as substrate the 3,3’-dibro-
mo-bis-substituted bisphosphite-rhodium catalyst (Rh/3) showed
best activity combined with high n-selectivity (Table 2, entry 2).
Here, a turnover frequency up to 2310 hꢀ1 and excellent linear/
branched ratio up to 95/5 were observed. Similarly, the hydrofor-
mylation of 1-octene in the presence of 3 occurred with a high
reaction rate (average rate = 1686 mol aldehyde per mol of Rh
Surprisingly, when using 2,20-dihydroxybiphenyl as bridging
part ring interconversion occurred and different compounds were
detected by 31P NMR. Nevertheless, from this mixture the asym-
metric diphosphite ligand 6 could be successfully isolated and its
structure is unambiguously proven by means of different NMR
spectroscopic data such as NOESY, COSY, HMQC, HMQC-TOCSY,
and HMBC (Scheme 3).
In order to understand the nature of catalytically active rho-
dium complexes of these ligands high pressure NMR studies were
performed in the presence of ligand 3 (Fig. 2). It is well known that
bidentate phosphite ligands form stable rhodium-hydride species,
denoted as [HRh(PP)(CO)2], which are characterized by a trigonal-
bipyramidal structure under typical hydroformylation condition
[19]. Hence, complex 8 was prepared in situ under 20 bar of CO/
H2 by adding 1.1 equivalent of 3 to the catalyst precursor
[Rh(acac)(CO)2]. From the lineshape (Fig. 2a, a doublet of triplet-
like patterns, splitting 252 Hz), which is not first order, a dinuclear
structure with chemically equivalent, but magnetically inequiva-
lent phosphorus atoms can be deduced. No clear statement is pos-
sible whether this intermediate has terminal or bridging carbonyl
groups, but such a complex has been described with the BIPHE-
PHOS ligand (10) [20]. Complex formation occurred within 1 h at
room temperature as evidenced by the presence of one broad
doublet in the 31P NMR spectra and one triplet of doublets for
R1
R1
R1
O
R2
R1
O
P
O
P O
O
O
P
O
O
O
O
P
O
O
R1
R1
R2
R1
R1
R1 = H, Br, alkyl, aryl
2 = H, Br,alkyl, aryl
= buta-1,3-dien-1,4-diyl, = butan-1,4-diyl
R
Fig. 1. Novel bisphosphite ligands.

I. Piras et al. / Journal of Organometallic Chemistry 695 (2010) 479–486
481
Br
Br
Br
Br
Br
O
O
O
P
O
P O
O
O
O
O
P
O
P
O
O
Br
Br
Br
Br
Br
3
4
(S,S,S)-
(S,S,S)-
R1
Br
OH
OH
O
O
+
+ Et3N/ DMAP
P
Cl
R1
Br
1
(S)-
(S)- 2
1a:
1b:
1c:
= buta-1,3-dien-1,4-diyl; R1= H
= butan-1,4-diyl; R1= H
= butan-1,4-diyl; R1= Br
Br
Br
O
P
O
O
P
O
O
O
Br
Br
(S,S,S)- 5
Scheme 2. Modular synthesis of ligands 3–5.
Br
O
Br
Br
Br
Br
O
O
O
O
OH
OH
O P
P
O
O
P
O
+
P
Cl
+
O
P
O
O
O
O
Br
Br
Br
Br
Br
(S,S)- 6
(S,S)- 7
Scheme 3. Synthesis of ligand 6.
H2/CO
H
P
P
P
P
P
CO OC
Rh Rh
CO OC
fast
Rh CO
CO
P
slow
8
a
b
[ppm]
180
170
160
150
166
164
162
160
c
- 9.7
- 9.9
- 10.0 [ppm]
- 9.8
Fig. 2. Formation of complex 8: (a) 31P NMR after 35 min under pressure at rt; (b) 31P NMR after 60 min under pressure at rt; (c) 1H NMR of the hydride complex at rt.

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I. Piras et al. / Journal of Organometallic Chemistry 695 (2010) 479–486
O
O
O
O
O
O
O
P
O
O
O
O
O
P
O
O
P
O
O
O
O P
P
P
O
O
O
O
O
O
O
10
11
9
Fig. 3. Known ligands 9, 10 and 11.
Table 1
Isomerization–hydroformylation of 2-pentene.
H2/CO
CHO
+
+
H
P
P
CHO
CHO
2-ethylbutanal
Rh CO
CO
Entrya
L
Rh/L
P (bar)
Yield%d
n/isoe
TOF (hꢀ1
)
1
20
20
20
50
10
20
20
20
20
20
20
20
20
17
77
46
63
85
85
26
40
84
45
85
39
82
41/59
90/10
88/12
81/19
90/10
90/10
90/10
85/15
89/11
88/12
69/31
96/4
179
824
495
677
914
916
1712
432
900
481
913
420
877
2
3
3
3
3
3
3
4
5
6
9
10
11
1/3
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
3b
4
5
6
7c
8
9
10
11
12
13
41/59
a
30 mmol of 2-pentene, 1.39 ꢁ 10ꢀ5 mol Rh(acac)(CO)2 (50 ppm Rh), Rh/L/substrate = 1/2/2146, 30 ml THF, isooctane as internal standard, CO/H2 = 1/1 constant, 2 h,
120 °C.
b
T = 100 °C.
Yield determined after 20 min.
Yield determined by GC analysis.
2-Ethylbutanal was not detected except in entry 1.
c
d
e
per h) and a high selectivity for the linear aldehyde (linear/
branched ratio of 96:4). Also in the reaction of less reactive 2-oc-
tene significant amounts of n-nonanal were found (n/iso ratio up
to 87:13; Table 2, entry 14), indicative of the high tendency of
these catalysts for alkene isomerization.
starting materials also mixtures of olefins are selectively converted
[24]]. Hence, domino isomerization–hydroformylation of a n-oc-
tene mixture containing only 3.3% of 1-octene led preferentially
to n-nonanal (n/iso selectivity = 84:16) (Table 3, entry 6).
No significant differences are observed between ligands 3 and 5,
which only differ in the bridging part (H8-BINOL versus BINOL).
However, the less bulky ligand 6 gave lower reaction rate in the
case of 1- and 2-pentene in comparison with ligands 3, 4, and 5
demonstrating the importance of steric bulkiness on both sides
of the bisphosphite.
Finally, several other olefins were hydroformylated in the pres-
ence of Rh(acac)(CO)2/3. The results of the catalytic reactions are
listed in Table 3. 2,3-Dimethyl-1-butene represents the class of
1,1-disubstituted alkenes. Here, the aldehyde selectivity and regi-
oselectivity is higher than 99%. Also in the case of 3,3-dimethyl-
1-butene the corresponding linear aldehyde is the exclusive reac-
tion product (Table 3, entry 2). The hydroformylation of styrene
proceeded preferentially to give the linear aldehyde, too (Table 3,
entry 5). However, due to the increased thermodynamic stability
of the intermediate benzylrhodium complex, the selectivity is low-
er. Interestingly, applying N-vinylphthalimide the major product is
the branched aldehyde due to the increased stability of the
branched metal complex (Table 3, entry 4). In addition to pure
3. Conclusions
In summary, new modular bisphosphite ligands have been con-
veniently synthesized. The corresponding rhodium complexes are
highly active catalysts for isomerization–hydroformylation reac-
tions of internal olefins. The active catalysts have been character-
ized by in situ NMR studies. Under model conditions some of the
new ligands display higher activity compared to highly active acyl-
phosphite 9 and BIPHEPHOS 10.
4. Experimental
4.1. General methods
All reactions were performed under argon atmosphere using
standard Schlenk techniques. The solvents were dried by standard
procedures, distilled and stored under argon.

I. Piras et al. / Journal of Organometallic Chemistry 695 (2010) 479–486
483
Table 2
Hydroformylation of benchmark olefins.
H2/CO
R
R
R
CHO
+
R
or
CHO
or
H
P
P
Rh CO
isomers
CO
Entrya
Olefin
Ligand
Yield (%)d
n/isoe
TOF (hꢀ1
)
1
2
3
4
5
6
7
1-pentene
1-pentene
1-pentene
1-pentene
1-pentene
1-pentene
1-pentene
1-octene
1-octene
1-octene
1-octene
1-octene
2-octene
2-octene
2-octene
2-octene
2-octene
95
86
94
83
78
90
75
11
82
76
78
76
21
73
54
77
59
48/52
95/5
74/26
95/5
94/6
87/13
99/1
48/52
96/4
96/4
92/8
95/5
32/68
87/13
86/14
85/15
85/15
2538
2310
2528
2226
2097
2410
2009
234
1686
1564
1605
1571
110
3
4
5
6
9
10
8b
9b
10b
11b
12b
13c
14c
15c
16c
17c
3
4
5
6
3
4
5
6
377
280
396
305
a
30 mmol of olefin, 5.59 ꢁ 10ꢀ6 mol Rh(acac)(CO)2 (20 ppm Rh), Rh/L/substrate = 1/3/5364, T = 100 °C, P = 50 bar (CO/H2 = 1/1) constant, 30 ml THF, isooctane as internal
standard, 2 h.
b
Rh(acac)(CO)2 (7.29 ꢁ 10ꢀ6 mol) (25 ppm Rh), Rh/L/substrate = 1/3/4111, T = 120 °C, P = 20 bar (CO/H2 = 1/1) constant.
c
d
e
Rh(acac)(CO)2 (1.46 ꢁ 10ꢀ5 mol) (50 ppm Rh), Rh/L/substrate = 1/3/2059, T = 120 °C, P = 20 bar (CO/H2 = 1/1) constant.
Yield of aldehyde determined by GC analysis.
2-Ethylbutanal was not detected except in entry 1; in the hydroformylation of 1-octene and 2-octene the branched aldehydes consist mainly of 2-methyloctanal. No
significant amounts (<2%) of other products were detected apart from isomerized olefin except in cases without any ligand added.
1H, 13C and 31P NMR spectra were recorded on Bruker Spec-
trometer AV 300 and AV 400. The calibration of 1H and 13C spectra
was carried out on solvent signals (dCDCl3 = 7.27 and 77.0;
dC6D6 = 7.16 and 128.06 and dCD2Cl2 = 5.32 and 53.8). The 31P
NMR chemical shifts are referenced to 85% H3PO4. The 1H and
13C NMR signals were assigned by DEPT spectra. EI mass spectra
were recorded on an MAT 95XP spectrometer (Thermo ELECTRON
CORPORATION). Chemical shifts are given in ppm and coupling
constants are reported in Hz. IR spectra were recorded as tolu-
ene-d8 on a Nicolet 6700 FT-IR. Hydroformylation reactions were
performed in100 ml autoclaves connected to burettes as gas reser-
voir that kept the CO/H2 gas pressure constant throughout the
reaction. The following compounds were prepared according to
the literature procedures: Octahydrobinaphthol 1b [25], (S)-3,3’–
dibromo–5,5’,6,6’,7,7’,8,8’-octahydro-1,1’-binaphthyl-2,2’–diol 1c
[26] and phosphorochloridite [27].
Table 3
Substrate screening with Rh/3 catalyst.
Entry
1a,b
Substrate
t (h)
Yield%g
41
n/iso
TOF (hꢀ1
875
)
2
>99
2a,c
3a,c
1
97
55
>99
2051
49
24
4.1.1. (11bS)-2,6-Dibromo-4-chloro-8,9,10,11,12,13,14,15-octahydro
dinaphtho[2,1-d:1’,2’-f][1,3,2]dioxaphosphepine 2
4a,d
2
80h
35/65i
1592
O
A three necked round-bottomed flask was charged with (S)-3,3’-
dibromo-5,5’,6,6’,7,7’,8,8’-octahydro-1,1’-binaphthyl-2,2’-diol 1c
(20 mmol) in toluene (200 ml). The solution was cooled at 0 °C.
Then a mixture containing PCl3 (21 mmol), toluene (30 ml) and
Et3N (46 mmol) was added slowly via cannula and the medium
was allowed to stir overnight at room temperature. The solvent
and slight excess of PCl3 were evaporated in vacuum. The com-
pound was crystallized from pentane. White crystals, 90% yield:
N
O
5e
6f
1
4
>99
84
70/30
84/16
1998
461
Octene mixture
a
b
c
30 mmol of substrate, T = 120 °C, P = 20 bar (CO/H2 = 1/1) constant, 30 ml THF.
Rh(acac)(CO)2 (7.09 ꢁ 10ꢀ6 mol) (25 ppm Rh), Rh/L/substrate = 1/3/4230.
Rh(acac)(CO)2 (1.41 ꢁ 10ꢀ6 mol), Rh/L = 1/2/2115.
31P NMR (121.5 MHz, CDCl3):
d
(ppm) = 171.9; 1H NMR
(300 MHz, CDCl3): d (ppm) = 7.38 (s, 2H, arom.), 2.86–2.74 (m,
4H, 2CH2), 2.62–2.46 (m, 2H, CH2), 2.31–2.12 (m, 2H, CH2), 1.85–
1.46 (m, 8H, 4CH2); 13C NMR (75 MHz, CDCl3): d (ppm) = 143.6
(d, J(P,C) = 3.2, C), 143.1 (d, J(P,C) = 3.9, C), 138.3 (d, J(P,C) = 1.9,
C), 137.6 (d, J(P,C) = 1.9, C), 137.4 (d, J(P,C) = 1.3, C), 136.6(d,
J(P,C) = 1.3, C), 133.4 (2C), 130.8 (C), 130.7 (C), 129.0 (d,
J(P,C) = 1.9, C), 112.9 (d, J(P,C) = 3.2, C), 112.5 (d, J(P,C) = 2.6, C),
29.1 (CH2), 29.1 (CH2), 27.8 (CH2), 27.6 (CH2), 22.5 (CH2), 22.4
(CH2), 22.3 (CH2), 22.2 (CH2); MS (70 eV, EI): m/z (%) = 516(7.31),
d
e
Rh Rh(acac)(CO)2 (50 ppm), Rh/L = 1/2.
30 mmol of substrate, 1.50 ꢁ 10ꢀ5 mol Rh(acac)(CO)2, Rh/L/substrate = 1/3/
2000, T = 100 °C, P = 20 bar (CO/H2 = 1/1), 15 ml toluene.
f
95 mmol of substrate (3.3% 1-octene, 48.4% Z/E-2-octene, 29.2% Z/E-3-octene,
16.4% Z/E-4-octene, 2.1% isomers, 0.6% octane), 4.32 ꢁ 10ꢀ5 mol Rh(acac)(CO)2
100 ppm Rh, Rh/L/substrate = 1/2/2203, 40.5 ml toluene, performed by Dr. D.
Selent/LIKAT Rostock.
g
Yield of aldehyde determined by GC analysis.
Isolated yield.
Regioselectivity determined by NMR.
h
i

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I. Piras et al. / Journal of Organometallic Chemistry 695 (2010) 479–486
452([M+],100), 399(2.69), 371(7.45), 329(2.65), 292(73.87),
274(14.81), 205(6.47), 165(6.87), 91(9.77), 69(13.63), 43(14.00);
HR-MS: (calc.) 513.90942, (found) 513.910640 for C20H18O2
Br2Cl1P1.
NMR (300 MHz, CD2Cl2): d (ppm) = 8.03 (s, 1H, arom.), 8.00 (s, 1H,
arom.), 7.94–7.89 (m, arom.), 7.88 (s, 1H, arom.), 7.85 (s, 1H,
arom.), 7.45–7.43 (m, arom.), 7.43–7.41 (m, 1H, arom.), 7.39 (s,
1H, arom.), 7.38–7.34 (m, arom.), 7.32–7.25 (m, arom.), 7.20–7.14
(m, arom.), 2.93–2.64 (m, CH2), 2.56–2.37 (m, CH2), 2.14–1.98 (m,
CH2), 177–1.60 (m, CH2), 1.53–1.37 (m, CH2); 13C NMR (75 MHz,
CD2Cl2): d (ppm) = 148.4, 143.5, 143.0, 138.1, 137.1, 136.9, 135.9,
134.1, 133.1, 132.9, 131.7, 131.5, 131.0, 130.3, 128.9, 128.7,
128.4, 127.6, 127.2, 125.8, 125.4, 124.5, 124.2, 123.1, 121.8,
118.2, 113.3, 112.7, 29.2 (2C), 29.1 (2C), 27.9 (2C), 27.7 (2C), 22.7
(4C), 22.5 (2C), 22.5 (2C); MS (70 eV, EI): m/z (%) = 1247 ([M+],
0.35),1169 (3.41), 1082 (0.36), 916 (4.00), 852 (1.34), 750
(100.00), 584 (9.42), 401 (3.62), 315 (11.14), 268 (28.20), 119
(5.66); HR-MS (ESI+-TOF/MS): [M+Na]+ (calc.) 1264.95518, (found)
1264.95262 for C60H48Br4 NaO6P2.
4.1.2. (1S)-2,2’-bis((11bS)-2,6-Dibromo-8,9,10,11,12,13,14,15-octahy
drodinaphtho[2,1-d:1’,2’-f][1,3,2]dioxaphosphepin-4-yloxy)-5,5’,6,6’,
7,7’,8,8’-octahydro-1,1’-binaphthyl 3
A solution of (S)-H8-binaphthol 1b (1.3 mmol), Et3N (3 mmol)
and DMAP (0.3 mmol) in toluene (20 ml) was added slowly to a
solution of the corresponding phosphoruschloridite 2 (2.63 mmol)
at 0 °C and this temperature was kept for 1 h. The reaction mixture
was stirred overnight and then filtered through a sintered glass
funnel. Evaporation of the solvent gave white foam.
Yield = >99%; (purity = >97%). 31P NMR (162 MHz, C6D6): d
(ppm) = 138.3; 1H NMR (400 MHz, C6D6):
d (ppm) = 7.79 (d,
J = 8.3, 2H, H8-BINOL), 7.20 (s, 2H, Br2–H8-BINOL), 7.09(s, 2H,
Br2–H8-BINOL), 6.98 (d, J = 8.3, 2H, H8-BINOL), 2.72–2.55 (m, 6H,
3CH2), 2.44–2.24 (m, 12H, 6CH2), 2.22–2.10 (m, 2H, CH2), 2.02–
1.86 (m, 4H, 2CH2), 1.62–1.49 (m, 6H, 3CH2), 1.49–1.30 (m, 14H,
7CH2), 1.29–1.05 (m, 4H, 2CH2); 13C NMR (100.6 MHz, C6D6): d
(ppm) = 147.9 (t, J(P,C) = 4.8, 2C), 144.5 (t, J(P,C) = 2.1, 2C), 143.9
(t, J(P,C) < 1, 2C), 137.9 (2C), 137.4 (2C), 136.6, (2C), 136.0 (2C),
135.1 (2C), 134.1 (2C), 133.3 (J(C,H) = 162 Hz, 2CH), 133.1
(J(C,H) = 163 Hz, 2CH), 131.4 (t, J(P,C) = 2.4, 2C), 129.8 (2CH),
129.3 (t, J(P,C) < 1, 2C), 129.0 (t, J(P,C) = 1.4, 2C), 119.1 (t,
J(P,C) = 5.2, 2CH), 114.1 (d, 2C, J(P,C) = 1.3), 113.7 (2C), 29.9
(2CH2), 28.9 (2CH2), 28.9 (2CH2), 28.1 (t, J(P,C) = 2.0, 2CH2), 27.8
(2CH2), 27.6 (2CH2), 23.3 (2CH2), 23.2 (2CH2), 22.6 (2CH2), 22.5
(4CH2), 22.4 (2CH2); MS (70 eV, EI): m/z (%) = 1254 ([M+], 0.56),
1175 (4.02), 1095 (1.24), 760 (17.39), 759 (48.46), 757 (100.00),
755 (44.88), 677 (7.34), 482 (7.34), 401 (8.62), 323 (17.65); HR-
MS: [M+Na]+ (calc.) 1273.01778, (found) 1273.01636; [M+K]+ (cal-
culated) 1288.99172, (found) 1288.99114 for C60H56Br4 O6P2.
4.1.5. (11bS)-2,6-Dibromo-4-((S)-3,3’-dibromo-2’-(dibenzo[d,f][1,3,2]
dioxaphosphepin-6-yloxy)-5,5’,6,6’,7,7’,8,8’-octahydro-1,1’-binaph
thyl-2-yloxy)-8,9,10,11,12,13,14,15-octahydrodinaphtho[2,1-d:1’,2’-
f][1,3,2]dioxaphosphepine 6
Treatment of chlorophosphite 2 and 2,20-dihydroxybiphenyl as
described for compound 3, afforded a mixture of bisphosphites as
a white powder. The compound 6 was isolated by precipitation in
Et2O. Isolated yield = 70%; 31P NMR (162 MHz, CD2Cl2):
d
(ppm) = 142.7 (d, J(P, P) = 50, 1P), 137.0 (d, J(P, P) = 50, 1P); 1H
NMR (400 MHz, CD2Cl2): d (ppm) = 7.58 (s, 1H, Br2–H8-BINOL),
7.47 ꢀ7.45 (m, 1H, Ph), 7.45–7.42 (m, 1H, Ph), 7.39–7.32 (m, 2H,
Ph), 7.30 (s, 2H, Br2–H8-BINOL and Ph), 7.28–7.27 (m, 1H, Ph),
7.26 (s, 1H, Br2–H8-BINOL), 7.22 (s, 1H, Br2–H8-BINOL), 7.14 (dt,
J = 8.0, J = 1.04, 1H, Ph), 6.86 (dt, J = 8.0, J = 1.0, 1H, Ph), 2.85–2.33
(m, 12H, 6CH2), 2.23–2.89 (m, 4H, 2CH2), 1.84–1.34 (m, 16H,
8CH2); 13C NMR (100.6 MHz, CD2Cl2): d (ppm) = 150.0 (d, C, J(P,
C) = 7.3, Ph), 149.0 (d, J(P, C) = 3.2, C, Ph), 146.4 (C), 144.9 (d, J(P,
C) = 6.8, C), 144.0 (d, J(P, C) = 5.0, C), 143.3 (d, J(P, C) = 2.8, C),
138.5 (C), 137.9 (d, J(P, C) = 1.6, C), 137.3 (C), 137.0 (C), 136.7 (d,
J(P, C) = 1.2, C), 136.2 (C), 135.7 (d, J(P, C) < 1, C), 135.3 (d, J(P,
C) < 1, C), 134.2 (CH), 133.4 (CH), 133.1 (CH), 133.0 (CH), 131.9
(d, JPC = 3.6, C, Ph), 130.9 (d, J(P, C) = 5.3, C), 130.8 (d, J(P, C) = 2.5,
C, Ph), 130.2 (C), 130.0 (CH, Ph), 129.9 (CH, Ph), 129.7 (d, J(P,
C) = 4.3, C),129.54 (CH, Ph),129.5 (d, J(P, C) < 2, C), 129.3 (CH, Ph),
128.5 (C), 125.8 (CH, Ph), 125.4 (CH, Ph), 123.1 (CH, Ph), 122.6 (d,
J(P, C) = 1.6, CH, Ph), 113.4 (d, J(P, C) = 2.6, C), 113.1 (C), 112.,7 (d,
J(P, C) = 5.0, C), 111.7 (d, C, J(P, C) = 2.5), 29.8 (CH2), 29.6 (CH2),
29.3 (CH2), 29.2 (CH2), 28.0 (CH2), 27.8 (CH2), 27.8 (CH2), 27.5
(CH2), 23.0 (CH2), 22.9 (CH2), 22.8 (2CH2), 22.8 (CH2), 22.7 (CH2),
22.7 (CH2), 22.6 (CH2). MS (70 eV, EI): m/z (%) = 1146 ([M+], 1.69),
1067 (10.70), 915 (36.47), 649 (100.00), 481 (13.16), 355 (15.71),
281 (16.79), 215 (29.13), 168 (30.25), 131 (18.00), 69 (62.55);
HR-MS (ESI+-TOF/MS): [M+Na]+ (calc.) 1164.92388, (found)
1164.92199; [M+K]+ (calc.) 1180.89782, (found) 1180.89876 for
C52H44Br4O6P2.
4.1.3. (11bS,11b’S)-4,4’-((S)-3,3’-Dibromo-5,5’,6,6’,7,7’,8,8’-octahydro
-1,1’-binaphthyl-2,2’-diyl)bis(oxy)bis(2,6-dibromo-8,9,10,11,12,13,
14,15-octahydrodinaphtho[2,1-d:1’,2’-f][1,3,2]dioxaphosphepine) 4
Treatment of chlorophosphite 2 and 1c, as described for com-
pound 3, afforded the bisphosphite
4 as a white powder.
Yield = >99% (purity = >94%). 31P NMR (121.5 MHz, CDCl3):
d
(ppm) = 137.0; 1H NMR (300 MHz, CDCl3): d (ppm) = 7.27 (s, 2H,
arom.), 7.24 (s, 2H, arom.), 7.15 (s, 2H, arom.), 2.85–2.67 (m, 8H,
4CH2), 2.65–2.39 (m, 8H, 4CH2), 2.35–2.07 (m, 6H, 3CH2), 2.03–
1.89 (m, 2H, CH2), 1.86–1.65 (m, 12H, 6CH2), 1.86–1.24 (m, 12H,
6CH2); 13C NMR (75 MHz, CDCl3): d (ppm) = 144.7 (m, 2C), 144.1
(m, 2C), 143.2 (2C), 137.2 (2C), 137.2 (2C), 136.4 (2C), 135.9 (2C),
134.9 (2C), 134.8 (2C), 132.9 (2CH), 132.9 (2CH), 132.8 (2CH),
130.7 (m, 2C), 130.6 (2C), 129.3 (2C), 113.8 (2C), 113.2 (2C),
112.2 (2C), 29.3 (2C), 29.1 (2C), 29.0 (2C), 27.9 (2C), 27.6 (4C),
22.7 (2C), 22.6 (4C), 22.6 (2C), 22.6 (2C), 22.4 (2C); MS (70 eV,
EI): m/z (%) = 1412 ([M+], 0.78), 1334 (3.70), 1254 (1.55), 1174
(2.82), 917 (69.86), 915 (100.00), 911 (18.84), 481 (18.45); HR-
MS: [M+Na]+ (calc.) 1434.83267, (found) 1434.83466 for
C60H54(79Br)3(81Br)3 NaO6P2.
4.1.6. 2,2’-Bis(8,9,10,11,12,13,14,15-octahydrodinaphtho[2,1-d:1’,2’-
f][1,3,2]dioxaphosphepin-4-yloxy)-5,5’,6,6’,7,7’,8,8’-octahydro-1,1’-
binaphthyl 11
4.1.6.1. Mixture of diastereomers. 31P NMR (162 MHz, CD2Cl2): d
(ppm) = 140.6, 138.8 (d, J(P, P) = 28, 1P), 137.5 (d, J(P, P) = 28, 1P),
138.6, 138.3. MS (70 eV, EI): m/z (%) = 938 ([M+], 2.37), 599
(100.00), 469 (4.44), 323 (19.38), 276 (6.35), 141 (0.81).
4.1.4. (1S)-2,2’-Bis((11bS)-2,6-dibromo-8,9,10,11,12,13,14,15-
octahydrodinaphtho[2,1-d:1’,2’-f][1,3,2]dioxaphosphepin-4-yloxy)-
1,1’-binaphthyl 5
A solution of (S)-BINOL 1a (0.8 mmol), Et3N (1.85 mmol) and
DMAP (0.3 mmol) in Et2O/THF (7/1, 20 ml) was added slowly to a
solution of the corresponding chlorophosphite 2 (1.65 mmol) in
Et2O at 0 °C and this temperature was kept for 1 h. The reaction
mixture was stirred overnight and then filtered through a sintered
glass funnel. Evaporation of the solvent gave white foam mixture.
31P NMR (121.5 MHz, CD2Cl2): d(ppm) = 136.6 (major pick 80%); 1H
4.2. In situ HP-NMR hydroformylation experiment
In a typical experiment, a sapphire tube was filled under Argon
with a solution of Rh(acac)(CO)2 (0.045 mmol) and ligand (molar
ratio PP/Rh = 1.1) in d8-toluene. The HP-NMR tube was pressurized
to 20 bar CO/H2 and afterwards heated to 80 °C.

I. Piras et al. / Journal of Organometallic Chemistry 695 (2010) 479–486
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4.3. [HRh(CO)2(3)] 8 at room temperature
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olefins;
31P NMR (121.5 MHz, d8-toluene): d (ppm) = 161.2 (broad d,
1J(Rh,P) = 240 Hz); 1H NMR (300 MHz, d8-toluene): d (ppm) =
16.00 (s, OH, enol), 7.99 (d, 2H, J = 8.22), 7.17 (s, 2H), 7.11 (s, 2H),
7.08 (d, 2H, J = 8.53), 4.88 (1H, acac), 2.82–2.66 (m, CH2), 1.54 (s,
6H, CH3 acac (enol)), 1.52–0.76 (m, CH2), ꢀ9.87 (dt, Rh–H,
2J(P,H) = 8.4 Hz, 1J(Rh,H) = 1.5 Hz); 103Rh NMR: d (ppm) = ꢀ1116;
(b) E. Drent, D.H.L. Pello, J.C.L.J. Suykerbuyk, J. Van Gogh, Shell Res., PCT Int
WO95/05354, 1995;
(c) E. Drent, W.W. Jager, Shell Oil Co., US5780684, 1998;
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1999;
(e) D. Konya, K. Almeida Lenero, E. Drent, Organometallics 25 (2006) 3166–
3174. Cobalt-catalyzed hydroformylation of internal olefins;
(f) A. Macaluso, O.W. Rigdon, US3907909, 1976;
IR: m .
CO = 2017.5, 1993.7 cmꢀ1
4.4. General procedure for hydroformylation experiments
(g) L.H. Slaugh, R.D. Mullineaux, Shell Oil Co., US3239569, 1966;
(h) M. Beller, J.G.E. Krauter, J. Mol. Catal. A 143 (1999) 31–39.
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C.B. Hansen, DSM/Du Pont, WO 97/33854, 1997.
The olefin is added under argon to a solution of Rh(acac)(CO)2
and the corresponding ligand in THF (30 ml). Then, the reaction
mixture is transferred into the autoclave (100 ml). The autoclave
is charged with syngas and heated at the indicated reaction tem-
perature. Then, the pressure is adjusted to the desired value
(20 bar or 50 bar for 1-pentene). After the reaction time the auto-
clave is cooled to 0 °C and the pressure is released. Isooctane was
used as internal standard. The resulting reaction mixture was
immediately analyzed by gas chromatography.
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(b) L.A. van der Veen, P.C.J. Kamer, P.W.N.M. van Leuween, Angew. Chem., Int.
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(c) L.A. van der Veen, P.C.J. Kamer, P.W.N.M. van Leuween, Organometallic 18
(1999) 4765–4777;
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Chem., Int. Ed. 40 (2001) 3408–3411;
Acknowledgements
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We gratefully acknowledge Evonik Oxeno, the state Mecklen-
burg-Vorpommern, the Bundesministerium für Bildung und Fors-
chung (BMBF), and the DFG (Leibniz-Price) for financial support.
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