Enantioselective catalysis; 130: Optically active expanded ligands based on the trans-1,2-substituted cyclopentane skeleton

Article abstract of DOI:10.1055/s-1999-3597

New expanded bisphosphane ligands with a chiral trans-1,2-substituted cyclopentane skeleton were prepared. Polyaldehydes were accessible by coupling optically active bisphosphane precursors with branched aryl bromides. Optically active expanded ligands were obtained by condensation of the aldehydes with chiral amines and amino alcohols. The optically active ligands were tested in several model reactions of enantioselective catalysis, including allylic alkylation, hydrogenation (adopted to the use of water), and hydrosilylation.

Full text of DOI:10.1055/s-1999-3597

1776
PAPER
Enantioselective Catalysis; 130:1 Optically Active Expanded Ligands Based on
the trans-1,2-Substituted Cyclopentane Skeleton
Henri Brunner,* Stefan Stefaniak, Manfred Zabel#
Institut für Anorganische Chemie, Universität Regensburg, D-93040 Regensburg, Germany
Fax +49(941)9434439; E-mail: henri.brunner@chemie.uni-regensburg.de
Received 1 April 1999
attack, were used for C-P coupling reactions. We also re-
Abstract: New expanded bisphosphane ligands with a chiral trans-
port the synthesis of ligands bearing eight bulky borneol
1,2-substituted cyclopentane skeleton were prepared. Polyalde-
groups attached as benzylic ethers, which show lipophilic
hydes were accessible by coupling optically active bisphosphane
precursors with branched aryl bromides. Optically active expanded
properties.9
ligands were obtained by condensation of the aldehydes with chiral
amines and amino alcohols. The optically active ligands were tested
in several model reactions of enantioselective catalysis, including
allylic alkylation, hydrogenation (adopted to the use of water), and
Bis(dichlorophosphanyl)cyclopentane [(S,S)-3]
hydrosilylation.
Synthesis of the Chiral Precursor (1S,2S)-1,2-
Key words: enantioselective catalysis, expanded ligands, chiral
phosphaneimines, aqueous catalysis
As a chiral chelate unit in the expanded phosphanes we
chose the C2-symmetric trans-substituted cyclopentane-
bisphosphane system. The resolution of the enantiomers
of the precursor trans-1,2-bis(dichlorophosphanyl)cyclo-
pentane (rac-3) was described recently.10 The key step,
the crystallization of a single diastereomer formed with
Introduction
(+)-diisopropyl tartrate (DIPT), had been published earli-
er.11 We used it to develop an alternative route to the
chiral dichlorophosphane (S,S)-3 compared to that de-
scribed in Ref. 10 (Scheme 1).
There is considerable interest in optically active phos-
phanes as cocatalysts in the homogeneous transition metal
catalyzed transformation of prochiral precursors into
chiral products. In earlier reports3-5 we tried to overcome
some of the disadvantages of the classic phenylated
ligands, such as lack of long-range influence on distant re-
action sites, e.g. in the allylic alkylation of barbiturates,6
by the dendrizyme concept.7 In the first approaches to the
design of expanded phosphanes a strongly chelating PP-
skeleton was equipped with dendritic substituents bearing
multiple chiral units in the periphery. Here we present a
new generation of this type of ligands, which combine the
structure of a successful chiral phosphane ligand with the
concept of expanded phosphanes. The previously de-
scribed ligands used achiral chelating structures such as
1,2-ethylene- or ortho-phenylene-bridged bisphosphanes,
which in the present study were replaced by trans-1,2-
substituted cyclopentane bearing two phosphorus atoms
as binding sites. Thus, the effective chiral element of the
ligand dpcp8 is introduced into the center of the new struc-
tures. The ligands presented here combine a chiral chelat-
ing core with the chiral dendritic extensions known from
earlier examples of expanded ligands.
Scheme 1
The dioxaphospholane (S,S)-111 was hydrolyzed in hydro-
chloric acid leading to the free phosphinic acid (S,S)-2,
which was isolated and characterized. In the second step
(S,S)-2 was chlorinated by stirring in PCl3 giving the de-
sired bisphosphonous acid dichloride (S,S)-3 in 21% total
yield. Compared with the known transformation involv-
ing reduction of (S,S)-1 with LiAlH4 followed by chlori-
nation of the pyrophoric bis-PH2 derivative 22 with
triphosgene, the formation of a pyrophoric phosphane and
the use of triphosgene can be avoided. A somewhat small-
er yield has to be accepted instead.
A convergent as well as a divergent reaction sequence will
be described to build up expanded structures. In both cas-
es substituted phenyl rings, that serve as branching units,
were attached to the phosphorus atoms. In the divergent
sequence the diphenylphosphane groups were further
functionalized after building up the phosphane by C-P
coupling reactions. The synthesis of several imine type
ligands derived from new polyaldehydephosphanes will
be described.9 Following the convergent route, prebuilt
aromatic precursors, which are stable against nucleophilic
The new compound (S,S)-2 was a non-crystallizing glassy
resin, soluble in water. Its 1H NMR spectrum in DMSO-
d6 showed two protons at δ = 6.92 with a strong coupling
constant of 1JH,P = 537 Hz indicating the predominance of
Synthesis 1999, No. 10, 1776–1784 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
Optically Active Expanded Ligands
1777
the hydroxyphosphanoyl tautomer with a proton attached
to each phosphorus atom.
Synthesis of the Polyaldehydephosphanes 6, 9, and 12
The synthesis of the phosphanes 6, 9, and 12 carrying four
or eight aldehyde functions is shown in Scheme 2. Start-
ing from the dimethyl acetals 4 and 10, the aromatic bro-
mide functions were lithiated with BuLi. The resulting
aryl-Li compounds were coupled to the bisdichlorophos-
phanes (S,S)-3 and 7 to form the tetra-/octaacetals 5, 8,
and 11, respectively. The structure of 5 is shown in Figure
1. The acetals were subsequently deprotected in aqueous
acid/acetone to give the aldehydes 6, 9, and 12.
Figure 1 Structure of 5. Selected distances
[Å] and angles [°]: C(25)–P(1) 1.86, P(1)–P(2) 4.45, C(25)–P(1)–
C(12) 103, P(1)–C(25)–C(29)–P(2) 161
The use of acetone as a transacetalization agent was not
feasible for the ortho-substituted tetraacetals 5 and 8.
When 5 was treated with aqueous acetone under acid ca-
talysis no aldehyde but addition products of acetone were
isolated. Instead half-concentrated hydrochloric acid12
could be applied for the acetal cleavage successfully, in
which the tetraacetals 5 and 8 dissolved readily. The low
yields observed in Ref. 12 could be increased by neutral-
izing with ammonia prior to extraction with dichlo-
romethane. The yellow ortho-aldehydephosphanes 6 and
9 crystallized from dichloromethane. Their structures
were determined by X-ray structure analysis.13 This study
showed conclusively that the aldehyde 6 had the (1S,2S)-
configuration at the cyclopentane ring (Figure 2).
Scheme 2
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1778
H. Brunner et al.
PAPER
Figure 2 Structure of 6. Selected distances [Å] and angles [°]: P(1)–
C(1) 1.86, P(1)–P(2) 4.42, C(1)–P(1)–C(6) 103, P1–C1–C2–P2 160
Figure 3 Structure of 9. Selected distances [Å] and angles [°]: P(1)–
C(19) 1.85, P(1)–P(2) 3.24, C(19)–P(1)–C(10) 100, P(1)–C(19)–
C(24)–P(2) 8
In the 1H NMR spectrum of 6 the signals of the aromatic The imines were characterized by their FD mass spectra,
and the aldehyde protons appear duplicated because the which showed the protonated molecular ion. In the com-
1
two phenyl substituents bound to the same phosphorus plex H NMR spectra most of the signals appeared dou-
atom are diastereotopic. Figure 3 shows the structure of bled as found for the aldehydes and were further split by
the phenylene-bridged tetraaldehyde 9. The distance be- E/Z-equilibria of the imine groups. The 31P NMR spectra
tween the two phosphorus atoms (3.24 Å) is much smaller exhibited sharp singlets in CD3OD, but broad multiplets
than in the case of 6 (4.42 Å).
Table 1 Imine Type Ligands and their Constituents
The Imine Type Ligands 13–19
Imine Type
Ligand
Aldehyde
Amine
The expanded imine type ligands were prepared by con-
densation of optically active amines with the tetra-/octaal-
dehydes 6, 9, and 12 (see Scheme 3 for 12, compounds
13–15 are described in the Experimental).
13
14
15
16
17
18
19
6
6
D-valinol
L-valinol
9
L-valinol
As the amine components we chose the commercially
available compounds D- and L-valinol, L-tert-leucinol,
and (R)-1-cyclohexylethylamine. The condensation was
carried out by stirring the aldehyde and the amine in tri-
methyl orthoformate for 24 hours. The resulting imine
type ligands are summarized in Table 1 (see also Experi-
mental).
12
12
12
12
D-valinol
L-valinol
L-tert-leucinol
(R)-1-cyclohexylethylamine
Scheme 3
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PAPER
Optically Active Expanded Ligands
1779
Scheme 4
in CDCl3. The E/Z-isomerism was assumed as the origin
of the multiplets. In order to prove this conclusion, a sam-
ple of the octaimine 16 was hydrogenated to the corre-
sponding octaamine with NaBH4 in methanol. After this
transformation, also in CDCl3 a sharp singlet in the 31P
NMR spectrum was observed. The elemental analyses of
the imine ligands showed deviations of the carbon per-
centage to lower values similar to those previously ob-
served and discussed for other phosphaneimines.5
Scheme 5
(13, 14, 16–19, (R,R)-21a, (S,S)-21b). In situ complexes
were also formed with [Rh(COD)Cl]2 for the hydrogena-
tion of α-acetamidocinnamic acid15 [13–19, (R,R)-21a,
Expanded Borneol Ligands
The ligands (R,R)-21a and (S,S)-21b were prepared from (S,S)-21b] and the hydrosilylation of acetophenone with
the branched aromatic bromide 20 bearing two (–)- diphenylsilane16,17(13–19). The catalytic reactions, their
borneol groups and the bisphosphonous dichlorides (R,R)- workup and analysis were performed following the proce-
3 and (S,S)-3 (Scheme 4). After a halogen-metal exchange dures described in the literature.6,15-17 Additionally, the so-
between BuLi and the aryl bromide 20 an organolithium dium salt of α-acetamidocinnamic acid was hydrogenated
species was formed, which reacted with (R,R)-3 and (S,S)- in a two-phase system using phase transfer techniques
3, respectively, to give either of the two possible diastere- [(R,R)-21a, (S,S)-21b] or with the water soluble ligand 23.
omers (R,R)-21a or (S,S)-21b. The two ligands form col-
orless solids, highly soluble in most solvents, also in
pentane. No difference between the two diastereomers Enantioselective Allylation of 1,5-Dimethylbarbitu-
1
could be detected in the H NMR spectra. However, the ric Acid with Allyl Acetate
chemical shifts of the 31P NMR signals differed by
∆δ = 0.4. Interestingly, also complexes formed with Chiral amino alcohols had shown promising results as a
[Rh(COD)Cl]2 or NiCl2 were soluble in pentane.9
functional part of phosphane ligands in the allylation of
barbiturates18 (highest optical induction reported up to
now 34% ee). Therefore, we incorporated valinol and tert-
leucinol into the periphery of the Schiff base ligands 13,
14, 16–19. The catalytic results obtained with these
The Water-soluble Hydroxymethylphosphane 23
In a one-step reaction (1S,2S)-1,2-bis[di(hydroxymeth- ligands in the reaction depicted in Scheme 6 are summa-
yl)phosphanyl]cyclopentane (23) (Scheme 5) was pre- rized in Table 2. The octaimines 16, 17, and 18 induced
pared from (1S,2S)-1,2-bisphosphanylcyclopentane11 (22) enantiomeric excesses in the range of 10–20% ee (Table
and aqueous formaldehyde by stirring with catalytic 2, Entries 1–3). The diastereomers 16 (L-valinol deriva-
amounts of K2[PtCl4].14
tive) and 17 (D-valinol derivative) exhibited a slight dif-
ference (Table 2, Entries 1, 2), but the direction of
induction was determined by the (1S,2S)-chelate struc-
ture, in contrast to former studies, in which the handed-
ness of the imines had determined the ee-values.6,18 The
Results of Catalytic Reactions
Pd complexes, generated in situ from Pd(acac)2 and the imine ligands 13, 14, 19 and the borneol ligands (R,R)-
given ligands, were used as catalysts in the asymmetric al- 21a, (S,S)-21b induced only low enantioselectivities (Ta-
lylation of 1,5-dimethylbarbituric acid with allyl acetate6 ble 2, Entries 4–8).
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1780
H. Brunner et al.
PAPER
Phase Transfer Hydrogenation of α-Acetamido-
cinnamic Acid Sodium Salt and Hydrogenation in
Water
A novel two-phase system for the hydrogenation of α-ac-
etamidocinnamic acid sodium salt (aacNa) was investi-
gated for the borneol ligands and the well-known chiral
bisphosphanes. The substrate aacNa was dissolved in wa-
ter, while the in situ catalyst was present in toluene. The
Rh/substrate ratio was 1:50 with a reaction time of 44
hours. Promoted by a phase transfer catalyst, under the
two-phase conditions, the ligands (R,R)-21a and (S,S)-
21b maintained their high enantioselectivities known
from monophasic hydrogenations, whilst the convention-
al phosphanes suffered a great loss of their selectivity. For
(R,R)-21a and (S,S)-21b 60–80% ee were achieved in sev-
eral experiments, but only 23% ee for dpcp,8 and less than
5% ee for diop20 and norphos.21 Only small amounts of
water were used in the system (aqueous slurry of sub-
strate) in order to assure complete hydrogenation.9
Scheme 6
Enantioselective Hydrogenation of α-Acetamidocin-
namic Acid
The Rh-catalyzed hydrogenation (Scheme 7) was carried
out in methanol at 20 bar H2 pressure for the imine type
ligands and at atmospheric pressure for the borneol
ligands. With all of the doubly meta-substituted ligands
16–19, (R,R)-21a, (S,S)-21b high optical inductions of
90–96% ee and full conversions were obtained (Table 3,
Entries 1–3, 7, 8). Ligand 17 seems to be a little more se-
lective than its diastereomer 16. The orientation of induc-
tion was governed by the chiral cyclopentane core. The
ortho-tetraimines 13–15 catalyzed the hydrogenation only
in part or not at all (Table 3, Entries 4–6). As observed
earlier, substitution in ortho-position of the ligand is unfa-
vorable for the catalytic hydrogenation.19
A water-soluble in situ catalyst was prepared from the hy-
droxymethylphosphanyl ligand 23 and [Rh(COD)Cl]2 by
stirring in water, which attained complete hydrogenation
of accNa at atmospheric H2 pressure. The product was ob-
tained with 22% ee (R).
Table 2 Enantioselective Allylation of 1,5-Dimethylbarbituric Acid
with Allyl Acetate, Pd(acac)2 and Bisphosphane Ligands in CH2Cl2/
toluene and Base DBUa
Enantioselective Hydrosilylation of Acetophenone
with Diphenylsilane
Entry
Ligand
Conversion (%)
(ee) %
The in situ catalysts for the enantioselective hydrosilyla-
tion of acetophenone with diphenylsilane (Scheme 8)
were prepared in acetophenone without any additional
solvent. All the experiments were carried out under argon.
The Rh/substrate ratio was 1:400 and the results are sum-
marized in Table 4. The octaimine 17 with eight D-valinol
groups afforded the highest enantioselectivity [23% ee,
1
2
3
4
5
6
7
8
16
39/20/19
79/30
86/86
36
12.5/18.4/19.2 (–)
10.2/13.6 (–)
16.7/14.2 (–)
0.4 (–)
17
18
19
13
75
1.4 (+)
14
72
2.6 (+)
Table 3 Hydrogenation of a-Acetamidocinnamic Acid with
[Rh(COD)Cl]2 and Bisphosphane Ligands in MeOHa
(R,R)-21a
(S,S)-21b
100
0
Entry
1b
Ligand
Conversion (%) (ee) %
100
0.6 (+)
a 1,5-Dimethylbarbituric acid (0.961 mmol, 150 mg), allyl acetate
(1.07 mmol, 115 mL), Pd(acac)2 (9.61 mmol, 2.93 mg) and bisphos-
phane ligands (19.2 mmol) in CH2Cl2/toluene (2:1, 30 mL) and base
DBU (1.01 mmol, 150 mL). Reaction conditions: 38°C, 72 h.
16
100
100
100
0
93–94 (R)
2b
17
96 (S)
93–94 (R)
–
3b
19
4b
13
5b
14
0/40
25/40
100
100
1 (S)
6b
15
1 (S)
7c
(R,R)-21a
(S,S)-21b
96 (S)
94 (R)
8c
Scheme 7
a a-Acetamidocinnamic acid (2.0 mmol, 410 mg), [Rh(COD)Cl]2 (10
mmol, 4.9 mg), bisphosphane ligands (22 mmol) and MeOH (10 mL).
b 20 bar.
c Atmospheric pressure.
Synthesis 1999, No. 10, 1776–1784 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
Optically Active Expanded Ligands
1781
(1S,2S)-1,2-Bis(hydroxyphosphanoyl)cyclopentane [(S,S)-2]
To a suspension of powdered (S,S)-111 (12.9 g, 21.7 mmol) in H2O
(50 mL) was added 6 M HCl (25 mL). The mixture was stirred for
1 h at r.t. and refluxed for 1 h. The H2O was removed at 80°C in vac-
uo to give a viscous oil. The oil was stirred in boiling acetone (100
mL), cooled with ice, and the solution decanted from the sediment-
ed product. This procedure was repeated twice. After drying in vac-
uo (0.001 mbar) at 80°C (S,S)-2 (2.98 g, 67%) remained as a highly
viscous colorless oil; [α]λ (c = 1, H2O, 22°C) +52 (589 nm), +54
(578 nm), +61 (546 nm), +101 (436 nm), +154 (365 nm).
(S), Table 4, Entry 1]. Remarkably, its diastereomer 16,
bearing eight L-valinol groups, gave only 12% ee of the
same configuration (Table 4, Entry 2), indicating a strong
influence of the peripheral groups. Except for 19 giving
19% ee (S) (Table 4, Entry 3) and 13 giving 6% ee (R)
(Table 4, Entry 4), the other ligands 14 and 15 induced
only low enantioselectivities (Table 4, Entries 5, 6) of the
(R)-configuration, regardless of the chelating core struc-
ture. For comparison (–)-diop was tested which gave a
21.6% ee (R) (Table 4, Entry 7).22
1H NMR (DMSO-d6): δ = 1.59–1.67 (m, 2 H, H-4), 1.69–1.89 (m,
4 H, H-3, 5), 2.20–2.27 (m, 2 H, H-1, 2), 6.92 (d, 2 H, 1JH,P = 536.7
Hz, HP), 10.59 (br, 2 H, POH).
31P{1H} NMR (DMSO-d6): δ = 34.90 (s).
MS (EI, 70 eV): m/z (%) = 163 (18, M+ – 2 H2O), 133 (28, MH+ –
P(OH)2), 67 [100, MH+ – 2 P(OH)2].
C5H12O4P2
(198.1)
calcd
C
30.32
30.29
H
6.11
6.29
found
Scheme 8
(1S,2S)-1,2-Bis(dichlorophosphanyl)cyclopentane [(S,S)-3]
Compound (S,S)-2 (2.89 g, 14.6 mmol) was stirred vigorously with
PCl3 (25.5 mL) at r.t. for 1 h and refluxed for 30 min. Compound
(S,S)-2 dissolved slowly, while a yellow precipitate was formed.
After concentrating to 1/3, the remaining solution was decanted
from the yellow precipitate and completely evaporated. The remain-
ing crude oil was submitted to a Kugelrohr distillation yielding
(S,S)-3 as a colorless oil (1.28 g, 32%); bp 70°C/0.001 mbar (Lit.8
bp 103–105/0.01 Torr, for racemate); [α]λ (c = 1, CH2Cl2,
22°C) +104 (589 nm), +109 (578 nm), +124 (546 nm).
All reactions involving phosphanes were carried out under purified
N2 using standard Schlenk techniques. Solvents were dried and de-
gassed according to standard procedures and stored under N2. H2O,
HCl and aq ammonia were degassed by bubbling N2 for 12 h. Chro-
matographic material (silica gel 60, 65–200 µm, Merck) was satu-
rated with N2. Merck silica gel 60 F254 plates were used for TLC.
3
1H NMR (CDCl3): δ = 1.87 (quint, JH,H = 7.0 Hz, 2 H, H-4), 2.22
Table 4 Hydrosilylation of Acetophenone with Diphenylsilane,
[Rh(COD)Cl]2 and Bisphosphane Ligandsa
(m, 4 H, H-3, 5), 2.82 (m, 2 H, H-1, 2).
31P{1H} NMR (CDCl3): δ = 190.31 (s).
Entry
Ligand
17
Yield (%)
75/87
ee (%)
1
2
3
4
5
6
7
22.7/24.6 (S)
3.5/4.3/8.2/11.9 (S)
18.5/19.4 (S)
3.2/6.4 (R)
0.4/0.6/2.7 (R)
1.5 (R)
(1S,2S)-1,2-Bis{di[2’-(dimethoxymethyl)phenyl]phosphanyl}-
cyclopentane (5); Typical Procedure
16
71/75/85/57
66/84
To a cooled solution (–78°C) of 4 (3.17 g, 13.7 mmol) in anhyd THF
(50 mL) was added dropwise BuLi (8.56 mL, 13.7 mmol, 1.6 M in
hexane). After stirring the solution for 30 min at this temperature,
(S,S)-3 (0.93 g, 3.43 mmol) in THF (10 mL) was added. The mix-
ture was allowed to warm up to r.t. within 12 h. The solvent was re-
moved and the residue was partitioned between Et2O (40 mL) and
H2O (10 mL). The ethereal layer was dried (Na2SO4) and the solvent
removed. The crude product was dissolved in CH2Cl2 (1–2 mL, vis-
cous solution). By adding MeOH (3 mL) at r.t. clear crystals of 5
(1.47 g, 58%) were obtained. From the mother liquor a second frac-
tion was collected by the same method; mp 75–77°C. [α]λ (c = 1,
CH2Cl2, 24°C) –294 (589 nm), –310 (578 nm), –358 (546 nm),
–678 (436 nm).
19
13
61/79
14
62/60/71
36
15
(–)-diop
88
21.6 (R)
a Acetophenone (8.5 mmol, 1.0 mL), diphenylsilane (8.6 mmol,
1.6 mL), [Rh(COD)Cl]2 (10 mmol, 4.9 mg) and bisphosphane ligands
(22 mmol). Reaction conditions: 0→20°C, 20 h.
1H NMR (CDCl3): δ = 1.61 (m, 2 H, H-4), 1.95 (m, 2 H, Ha-3, 5),
2.37 (m, 2 H, Hb-3, 5), 2.99 (m, 2 H, H-1, 2), 2.41, 3.24, 3.42, 3.61
(4 s, 4 × 6 H, CH3), 5.98, 6.29 [2 d, 2 × 2 H, JH,P = 5.0 Hz,
CH(OMe)2], 6.56–6.62, 7.11–7.16, 7.28–7.33, 7.54–7.61 (4 m, 4, 2,
4, 6 H, Harom).
31P{1H} NMR (CDCl3): δ = –40.54 (s).
MS (FD, CH2Cl2): m/z = 734 (M+).
Melting points: SMP-20 (Büchi), not corrected. MS: MAT 311 A
4
(EI) and MAT 95 (FD) (both Finnigan). Optical rotations: Perkin-
1
Elmer model 241 polarimeter (1 dm cells at r.t.). H NMR: ARX
400 (Bruker, 400 MHz), internal standard TMS. 31P NMR: ARX
400 (1H-decoupled, 162 MHz), external standard 85% H3PO4.
The following compounds were synthesized according to the litera-
ture: 1-bromo-2-(dimethoxymethyl)benzene (4),23 1-bromo-3,5-
C41H52O8P2
(734.8)
calcd
C
67.02
66.89
H
7.13
7.15
bis(dimethoxymethyl)benzene
(10),5
(–)-1-bromo-3,5-
found
bis(borneoxymethyl)benzene (20),2 trans-1,2-bis(dichlorophospha-
nyl)cyclopentane (rac-3),8 tetraisopropyl 2,2'-[(1S,2S)-cyclopen-
tane-1,2-diyl]bis[(4R,5R)-1,3,2-dioxaphospholane-4,5-
(1S,2S)-1,2-Bis[di(2’-formylphenyl)phosphanyl]cyclopentane
(6); Typical Procedure
Compound 5 (1.00 g, 1.36 mmol) was suspended in 6 M HCl (60
mL) and stirred for 10 min at 60°C. The mixture was cooled in an
dicarboxylate] [(S,S)-1],11 1,2-bis(dichlorophosphanyl)benzene
(7),24,25 trans-1,2-bis(dichlorophosphanyl)cyclopentane (22).11
BuLi was used as a 1.6 M solution in hexane (Merck).
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1782
H. Brunner et al.
PAPER
ice bath and then CH2Cl2 (30 mL) and 7 M NH3 were added until
the mixture was basic. On completion of neutralization, the color of
the organic phase had changed from yellow to orange. It was sepa-
rated and the aqueous phase was extracted with CH2Cl2 (2 × 30
mL). The combined CH2Cl2 solutions were dried (Na2SO4) and
evaporated. The crude product was purified by chromatography on
silica gel (3 × 20 cm) with CH2Cl2/EtOAc (1:1) eluting the first yel-
low fraction. Yellow crystals of 6 (0.45 g, 60%) were obtained by
evaporation from a solution in CH2Cl2; mp 204–205°C. [α]λ (c = 1,
CH2Cl2, 24 °C) = +83° (589 nm), +102° (578 nm), +198° (546 nm),
+2004° (436 nm).
1H NMR (CDCl3): δ = 1.30–1.38 (m, 2 H, H-4), 1.51–1.60 (m, 2 H,
Ha-3, 5), 1.79–1.98 (m, 2 H, Hb-3, 5), 2.81–2.83 (m, 2 H, H-1, 2),
3.20, 3.24, 3.26, 3.27 (4 s, 4 × 12 H, CH3), 5.29, 5.36 [2 s, 2 × 4 H,
8 × CH(OMe)2], 7.38–7.41 (m, 6 Harom), 7.47–7.51 (m, 6 Harom).
31P{1H} NMR (CDCl3): δ = –3.95 (s).
MS (FD, CH2Cl2): m/z = 1030 (M+).
C53H76O16P2 calcd
(1031.1) found
C
61.74
61.65
H
7.43
7.51
(1S,2S)-1,2-Bis[di(3’,5’-diformylphenyl)phosphanyl]cyclopen-
tane (12)
1H NMR (CD2Cl2): δ = 1.70 (m, 2 H, H-4), 1.96 (m, 2 H, Ha-3, 5),
2.43 (m, 2 H, Hb-3, 5), 2.66 (m, 2 H, H-1, 2), 6.48–6.50, 6.93–6.97,
To a solution of 11 (2.22 g, 2.06 mmol) in acetone (40 mL) were
added H2O (12 mL) and 6 M HCl (5 mL). The mixture was stirred
at 80°C for 15 min, while 12 precipitated as a fluffy solid. After
cooling with ice the precipitate was dissolved by adding CH2Cl2 (30
mL) and the phases were separated. The aqueous phase was extract-
ed with CH2Cl2 (2 × 40 mL). From the combined organic phases,
which were dried (Na2SO4) and evaporated, 12 was obtained as a
yellowish solid (1.52 g, 90%). It was recrystallized from THF (40
to –30°C) to give microscopic needles. Enclosed solvent could be
removed by heating at 140°C in high vacuum for 15 min; mp
>245°C (dec.); [α]λ (c = 1, CH2Cl2, 22°C) –170 (589 nm), –176
(578 nm), –200 (546 nm), −305 (436 nm).
7.28–7.31, 7.47–7.55, 7.61–7.65, 7.83–7.87 (6 m, 4, 2, 4, 2, 2, 2 H,
4
H
arom), 10.24 (d, 2 H, JH,P = 4.4 Hz, CHaO), 11.06 (d, 2 H,
4JH,P = 7.3 Hz, CHbO).
31P{1H} NMR (CD2Cl2): δ = –30.02 (s).
MS (FD, CH2Cl2): m/z = 550 (M+).
C33H28O4P2
(550.5)
calcd
C
72.00
71.68
H
5.13
5.34
found
1,2-Bis{di[2’-(dimethoxymethyl)phenyl]phosphanyl}benzene
(8)
Compound 4 (7.96 g, 34.4 mmol) in THF (100 mL), BuLi
(21.5 mL, 34.4 mmol, 1.6 M in hexane), and 7 (2.41 g, 8.61 mmol)
were reacted at –78°C as described for the preparation of 5. After
the same workup procedure 8 was crystallized by adding MeOH (3
mL) to a solution in CH2Cl2 (2 mL) giving 2.11 g (33%) of a color-
less crystalline mass.
1H NMR (CDCl3): δ = 2.92, 3.12 (2 s, 2 × 12 H, CH3), 5.65 [m, 4 H,
CH(OMe)2], 6.89–7.60 (m, 20 H, Harom).
31P{1H} NMR (CDCl3): δ = –31.40 (s).
MS (FD, CH2Cl2): m/z = 742 (M+).
1H NMR (CD2Cl2): δ = 1.54–1.69 (m, 2 H, H-4), 1.70–1.78 (m, 2 H,
Ha-3, 5), 2.06–2.18 (m, 2 H, Hb-3, 5), 2.86–2.98 (m, 2 H, H-1, 2),
7.89 (dd, 4 H, 3JH,P = 6.5 Hz, 4JH,H = 1.4 Hz, Ha-2', 6'), 8.01 (t, 2 H,
3
4JH,H = 1.4 Hz, Ha-4'), 8.11 (dd, 4 H, JH,P = 6.5 Hz, 4JH,H = 1.4 Hz,
4
Hb-2', 6'), 8.24 (t, 2 H, JH,H = 1.4 Hz, Hb-4'), 9.81 (s, 4 H, CHaO),
9.99 (s, 4 H, CHbO).
31P{1H} NMR (CD2Cl2): δ = –0.02 (s).
MS (FD, CH2Cl2): m/z = 662 (M+).
C37H28O8P2
(662.6)
calcd
C
67.07
66.34
H
4.26
4.26
found
C42H48O8P2
(742.7)
calcd
C
67.91
67.50
H
6.51
6.55
found
Tetra-/Octaimine Type Ligands 13–19, General Procedure
A defined amount of the tetra-/octaaldehyde 6, 9, or 12 (0.5 mmol)
was suspended in trimethyl orthoformate (50 mL). To the stirred
mixture was added the stoichiometric amount of the amine compo-
nent (4–8 equiv). After stirring for 24 h at r.t. all volatile constitu-
ents were removed to give slightly yellowish powders of the tetra-/
octaimines. The tetraimines were recrystallized from hot toluene/
petroleum ether, the octaimines from a solution in CH2Cl2 by add-
ing cyclohexane.
1,2-Bis[di(2’-formylphenyl)phosphanyl]benzene (9)
Compound 9 was obtained from 8 (2.00 g, 2.69 mmol) with 6 M
HCl (120 mL) by the method described for 6. After purification 9
was obtained from a solution in CH2Cl2 as yellow crystals (681 mg,
45%); mp 197–199°C.
1H NMR (CD2Cl2): δ = 6.93 (dd, 2 H, 3JH,H = 5.7 Hz, 4JH,H = 3.3 Hz,
3
Harom-3, 6), 6.97 (m, 4 H, H’arom), 7.27 (dd, 2 H, JH,H = 5.7 Hz,
4JH,H = 3.3 Hz, Harom-4, 5), 7.41 (m, 4 H, H’arom), 7.50 (m, 4 H,
H’arom), 7.90 (m, 4 H, H’arom), 10.29 (s, 4 H, CHO).
(1S,2S)-1,2-Bis{di[2’-(N-methylidene-(S)-valinol)phenyl]phos-
phanyl}cyclopentane (13)
31P{1H} NMR (CD2Cl2): δ = –23.55 (s).
MS (FD, CH2Cl2): m/z = 558 (M+).
According to the General Procedure, 6 (105 mg, 0.190 mmol) and
L-(+)-valinol (78.6 mg, 0.760 mmol) were reacted to give 13 (146
mg, 86%) as a yellow powder; mp 98–100°C (dec.); [α]λ (c = 1,
CH2Cl2, 22°C) –16 (589 nm), –17 (578 nm), –22 (546 nm), –9 (436
nm), –51 (365 nm).
C34H24O4P2
(558.5)
calcd
C
73.12
72.67
H
4.33
4.58
found
1H NMR (CD3OD): δ = 0.67–0.97 (m, 24 H, CH3), 1.64–1.75 (m,
2 H, H-4), 1.79–1.88 (m, 2 H, Ha-3, 5), 1.91–2.01 (m, 4 H, CHMe2),
2.37–2.54 (m, 2 H, Hb-3, 5), 2.75–2.84 (m, 4 H, NCH), 3.04–3.09
(m, 2 H, H-1, 2), 3.42–3.91 (m, 8 H, CH2O), 6.49–7.92 (m, 16 H,
(1S,2S)-1,2-Bis{di[3’,5’-bis(dimethoxymethyl)phenyl]phospha-
nyl}cyclopentane (11)
A solution of 10 (4.71 g, 15.5 mmol) in THF (100 mL), BuLi (9.60
mL, 16.7 mmol, 1.6 M in hexane), and (S,S)-3 (1.05 g, 3.86 mmol)
in THF (10 mL) were reacted at –78°C as described for the prepa-
ration for 5. The same workup procedure was applied. The yellow-
ish crude oil was purified by chromatography on silica gel with
Et2O (visualization with 366 nm light). After evaporation of the
product fractions, 11 was obtained as a colorless resin (3.20 g,
81%); [α]λ (c = 1, CH2Cl2, 22°C) –60 (589 nm), –63 (578 nm), –73
(546 nm), –149 (436 nm), –298 (365 nm).
4
Harom), 8.74 (d, 2 H, JH,P = 3.9 Hz, CHa=N), 9.26 (d, 2 H,
4JH,P = 5.6 Hz, CHb=N).
31P{1H} NMR (CD3OD): δ = –33.49 (s).
MS (FD, CH2Cl2): m/z = 890 (100, M+), 907 (5, MHO+).
(1S,2S)-1,2-Bis{di[2’-(N-methylidene-(R)-valinol)phenyl]phos-
phanyl}cyclopentane (14)
Reaction of 6 (115 mg, 0.210 mmol) and D-(–)-valinol (87.1 mg,
0.840 mmol) according to the General Procedure gave 14 (166 mg,
Synthesis 1999, No. 10, 1776–1784 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
Optically Active Expanded Ligands
1783
89%) as a yellowish powder; mp 54–56°C (dec.). [α]λ (c = 1,
CH2Cl2, 22 °C) +15 (589 nm), +16 (578 nm), +21 (546 nm), +117
(436 nm).
1H NMR (CD3OD): δ = 0.50–1.04 (m, 24 H, CH3), 1.63–1.83 (m,
4 H, H-4, Ha-3, 5), 1.96–2.10 (m, 4 H, CHMe2), 2.38–2.55 (m, 2 H,
Hb-3, 5), 2.74–2.85 (m, 4 H, NCH), 3.03–3.11 (m, 2 H, H-1, 2),
3.87–3.52 (m, 8 H, CH2O), 6.35–7.98 (m, 16 H, Harom), 8.84 (d, 2 H,
4JH,P = 4.5 Hz, CHa=N), 9.30 (d, 2 H, 4JH,P = 5.7 Hz, CHb=N).
MS (FD, CH2Cl2): m/z = 1456 (100, MH+), 1472 (90, MHO+), 1488
(30, MHO2 ).
+
(1S,2S)-1,2-Bis{di[3’,5’-di(N-methylidene-(R)-1-
cyclohexylethylamine)phenyl]phosphanyl}cyclopentane (19)
Following the General Procedure 12 (101 mg, 0.153 mmol) and
(R)-(–)-1-cyclohexylethylamine (158 mg, 1.22 mmol) were reacted
to afford 19 as a yellow powder (195 mg, 82%); mp 88–96°C (dec.);
[α]λ (c = 1, CH2Cl2, 22°C) –180 (589 nm), –189 (578 nm), –222
(546 nm), –443 (436 nm), –953 (365 nm).
1H NMR (CD3OD): δ = 0.83–1.82 (m, 114 H, C6H11, CH3, H-4),
2.02–2.05 (m, 2 H, H-3, 5), 2.93–3.02 (m, 10 H, CHMe, H-1, 2),
7.67 (d, 4 H, 3JH,P = 6 Hz, Ha-2', 6'), 7.80 (d, 4 H, 3JH,P = 6 Hz, Hb-2',
6'), 7.93 (s, 2 H, Ha-4'), 8.01 (s, 4 H, CHa=N), 8.09 (s, 2 H, Hb-4'),
8.18 (s, 4 H, CHb=N).
31P{1H} NMR (CD3OD): δ = –36.79 (s).
MS (FD, CH2Cl2): m/z = 890 (M+).
1,2-Bis{di[3’,5’-di(N-methylidene-(S)-valinol)phenyl]phospha-
nyl}benzene (15)
Reaction of 9 (200 mg, 0.358 mmol) and L-(+)-valinol (148 mg,
1.43 mmol) as described in the General Procedure gave 15 (208 mg,
65%) as a yellow powder; mp 218–240°C; [α]λ (c = 1, CH2Cl2,
22°C) = –78 (589 nm), –79 (578 nm), –83 (546 nm), –47 (436 nm).
1H NMR (CD3OD): δ = 0.39–0.89 (m, 24 H, CH3), 1.60–1.94 (m, 4
H, CHMe2), 2.66–2.89 (m, 4 H, NCH), 3.13–3.72 (m, 8 H, CH2O),
6.75–8.87 (m, 20 H, CH=N, Harom,).
31P{1H} NMR (CD3OD): δ = –5.47 (s).
MS (FD, MeOH): m/z = 1536 (65, MH+), 1552 (100, MHO+), 1568
+
(30, MHO2 ).
(1S,2S)-1,2-Bis{di[3’,5’-bis(borneoxymethyl)phenyl]phos-
phanyl}cyclopentane [(S,S)-21b]
31P{1H} NMR (CD3OD): δ = 41.87 (s).
To a stirred solution of 20 (1.67 g, 3.41 mmol) in THF (20 mL) was
added BuLi (3.2 mmol, 2.0 mL, 1.6 M in hexane) at –78°C. After
30 min (S,S)-3 (0.15 g, 0.57 mmol) was slowly added. The mixture
was allowed to warm to r.t. and stirred for 12 h. The solvent was re-
placed by Et2O, leading to a cloudy solution, which was washed
with H2O (5 mL). After drying and concentrating of the organic
phase (S,S)-21b resulted as a colorless substance, which was puri-
fied by recrystallizing from hot EtOH; mp 80–82°C; [α]λ (c = 1,
CH2Cl2, 22°C) –101 (589 nm), –105 (578 nm), –121 (546 nm).
1H NMR (CDCl3): δ = 0.79–2.10 (5 m, 134 H, bornyl without OCH,
H-3, 4, 5), 2.77–2.79 (m, 2 H, H-1, 2), 3.58–3.65 (m, 8 H, OCH-
bornyl), 4.26–4.53 (m, 16 H, CH2O), 7.10–7.32 (m, 12 H, Harom).
31P{1H} NMR (CDCl3): δ = –2.27 (s).
MS (FD, CH2Cl2): m/z = 1768 (MH+).
MS (FD, MeOH): m/z = 898 (100, M+), 914 (20, MHO+), 931 (48,
+
MO2 ).
(1S,2S)-1,2-Bis{di[3’,5’-di(N-methylidene-(S)-valinol)phe-
nyl]phosphanyl}cyclopentane (16)
According to the General Procedure, 12 (354 mg, 0.534 mmol) and
L-(+)-valinol (441 mg, 4.27 mmol) were reacted to give 16 (410 mg,
57%) as a yellow powder; mp 100–109°C (dec.); [α]λ (c = 1,
CH2Cl2, 22°C) –28 (589 nm), –29 (578 nm), –35 (546 nm), –86
(436 nm), –185 (365 nm).
1H NMR (CD3OD): δ = 0.83–1.08 (m, 48 H, CH3), 1.60–1.74 (m,
2 H, H-4), 1.86–1.99 (m, 10 H, CHMe2, Ha-3, 5), 2.02–2.17 (m, 2
H, Hb-3, 5), 2.94–3.05 (m, 10 H, NCH, H-1, 2), 3.60–3.71, 3.76–
3.86 (2 m, 2 × 8 H, CH2O), 7.78–8.29 (m, 20 H, Harom, CH=N).
31P{1H} NMR (CD3OD): δ = –4.07(s).
MS (FD, MeOH): m/z = 1344 (100, MH+), 1360 (15, MHO+).
C117H172O8P2 calcd
(1768.6) found
C
79.46
78.48
H
9.80
9.68
(1S,2S)-1,2-Bis{di[3’,5’-di(N-methylidene-(R)-valinol)phe-
nyl]phosphanyl}cyclopentane (17)
(1R,2R)-1,2-Bis{di[3’,5’-bis(borneoxymethyl)phenyl]phospha-
nyl}cyclopentane [(R,R)-21a]
Analogous to (S,S)-21b, (R,R)-21a was prepared from (R,R)-3,
which was available from the enantiomeric precursors; [α]λ (c = 1,
CH2Cl2, 22°C) –28 (589 nm), –30 (578 nm), –31 (546 nm).
1H NMR (CDCl3): identical to (S,S)-21b.
31P{1H} NMR (CDCl3): δ = –2.65 (s).
Reaction of 12 (183 mg, 0.276 mmol) and D-(–)-valinol (228 mg,
2.21 mmol) according to the General Procedure gave 17 (226 mg,
61%) as a yellow powder; mp 105–108°C (dec.); [α]λ (c = 1,
CH2Cl2, 22°C) –156 (589 nm), –165 (578 nm), –192 (546 nm), –
357 (436 nm), –697 (365 nm).
1H NMR (CD3OD): δ = 0.81–1.00 (m, 48 H, CH3), 1.63–1.79 (m,
2 H, H-4), 1.83 –2.02 (m, 10 H, CHMe2, Ha-3, 5), 2.31–2.46 (m, 2
H, Hb-3, 5), 2.93–3.10 (m, 10 H, NCH, H-1, 2), 3.58–3.61 and 3.69–
3.90 (2 m, 2 × 8 H, CH2O), 7.54–8.34 (m, 20 H, Harom, CH=N).
(1S,2S)-1,2-Bis[di(hydroxymethyl)phosphanyl]cyclopentane
(23)
Compound 22 (500 mg, 3.73 mmol) was added to a solution of aq
formaldehyde (35%, 1.50 mL, 18.7 mmol), H2O (3 mL), and
K2[PtCl4] (12 mg). After stirring 24 h at r.t., the phosphane had dis-
solved in the H2O phase and a black solid appeared, which was re-
moved by filtration. After removing all volatile matters in high
vacuum at 60°C 23 remained as a glassy resin (3.63 mmol, 97%).
31P{1H} NMR (CD3OD): δ = –7.13 (s).
MS (FD, MeOH): m/z = 1344 (100, MH+), 1360 (10, MHO+).
(1S,2S)-1,2-Bis{di[3’,5’-di(N-methylidene-(R)-tert-
leucinol)phenyl]phosphanyl}cyclopentane (18)
Reaction of 12 (200 mg, 0.302 mmol) and L-(+)-tert-leucinol
(307 mg, 2.41 mmol) as described in the General Procedure gave 18
(303 mg, 69%) as a yellow powder; mp 165–170°C; [α]λ (c = 1,
CH2Cl2, 21°C) –28 (589 nm), –29 (578 nm), –33 (546 nm), –82
(436 nm), –206 (365 nm).
1H NMR (CD3OD): δ = 0.94–1.00 (m, 72 H, CH3), 1.61–2.19 (m, 6
H, H-3, 4, 5), 2.87–2.98 (m, 8 H, NCH), 3.04–3.15 (m, 2 H, H-1, 2),
3.58–3.70, 3.85–3.94 (2 m, 2 × 8 H, CH2O), 7.72–8.40 (m, 20 H,
Harom, CH=N).
1H NMR (DMSO-d6) : δ = 1.53–1.90 (m, 6 H, H-3, 4, 5), 2.09–2.27
(m, 2 H, H-1, 2), 3.73–3.98 (m, 8 H, PCH2), 5.11 (br s, 4 H, OH).
31P{1H} NMR (DMSO-d6): δ = –14.92 (s).
Phase Transfer Hydrogenation of α-Acetamidocinnamic Acid
Sodium Salt
The sodium salt of α-acetamidocinnamic acid (aacNa) was pre-
pared by dissolving α-acetamidocinnamic acid (1.64 g, 8.00 mmol)
in MeOH (30 mL) and neutralizing with solid NaOH (320 mg, 8
mmol). The solvent was removed and the resulting white powder,
31P{1H} NMR (CD3OD): δ = –4.29 (s).
Synthesis 1999, No. 10, 1776–1784 ISSN 0039-7881 © Thieme Stuttgart · New York

1784
H. Brunner et al.
PAPER
consisting of aacNa, was dried in vacuo 3 h at 40°C. H2O (0.5 mL)
and 18-crown-6 (47 mg, 0.18 mmol) were added to aacNa (454 mg,
2.00 mmol) in an autoclave while stirring. To the homogeneous
slurry the organic catalyst phase was added, prepared by adding tol-
uene (10 mL) to a stirred mixture of the bidentate ligand (44 µmol)
and [Rh(COD)Cl]2 (9.86 mg, 20 µmol). After flushing with H2 the
mixture was stirred vigorously at 20 bar H2 pressure for 44 h. For
workup the clear aqueous phase was diluted with H2O (0.5 mL),
separated, acidified with 2 M HCl (1.0 mL) and treated further as
described for the homogeneous hydrogenation.15
References
# X-ray structure analysis
(1) Part 129: Brunner, H.; Mijolovic, D. J. Organomet. Chem.
1999, 577, 346.
(2) Brunner, H.; Fürst, J.; Ziegler, J. J. Organomet. Chem. 1992,
454, 87.
(3) Brunner, H.; Fürst, J. Tetrahedron 1994, 50, 4303.
(4) Brunner, H.; Bublak, P. Synthesis 1995, 36.
(5) Brunner, H.; Janura, M.; Stefaniak, S. Synthesis 1998, 1742.
(6) Brunner, H.; Deml, I.; Dirnberger, W.; Nuber, B.; Reißer, W.
Eur. J. Inorg. Chem. 1998, 43.
(7) Brunner, H. J. Organomet. Chem. 1995, 500, 39.
(8) Allen, D.L.; Gibson, V.C.; Green, M.L.H.; Skinner, J.F.;
Bashkin, J.; Grebenik, P.D. J. Chem. Soc., Chem. Commun.
1983, 895.
(9) Stefaniak, S. Dissertation, University of Regensburg, 1999.
(10) Kaunert, A.; Dahlenburg, L. Eur. J. Inorg. Chem. 1998, 885.
(11) Eckert, C.; Dahlenburg, L.; Wolski, A. Z. Naturforsch., B:
Chem. Sci. 1995, 50, 1004.
(12) Hellwinkel, D.; Krapp, W. Chem. Ber. 1978, 111, 13.
(13) Crystallographic data (excluding structure factors) for the
structures in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary
publication nos. CCDC 116248 (for 5), CCDC 116249 (for 6),
and CCDC 116250 (for 9). Copies of the data can be obtained,
free of charge, on application to CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (fax: +44 1223 336033 or e-mail:
deposit@ccdc.cam.ac.uk).
X-Ray Structure Analysis of 5
C41H52O8P2∑0.5MeOH, MW = 750.83; colorless prisms; crystal
size [mm]: 1.0 × 0.7 × 0.5; space group P 21; monoclinic; Z = 2; a/
b/c [Å] = 13.099(4)/ 9.656(3)/ 17.758(5);
b [°] = 109.64(2);
V = 2115(1) Å3; dcalcd = 1.18 g cm-3; F(000) = 802; m = 0.15 mm-1;
T = 293 K; ω-scan: 3.0° < 2θ < 52.5°; 8290 reflections collected,
8104 independent, 4632 observed (I > 2.5s(I)); Rint = 0.047; empir-
ical absorption correction; diffractometer Syntex R3 (Mo-Ka,
graphite monochromator); structure solution by direct methods with
SHELXTL PLUS; refinement: full-matrix least-squares on F2;
R = 0.076, Rw = 0.069; gof = 3.44.
X-Ray Structure Analysis of 6
C33H28O4P2, MW = 550.53; yellow clear prisms; crystal size
[mm]: 0.6 × 0.3 × 0.2; space group P 21; monoclinic; Z = 2;
a/b/c [Å] = 11.351(1)/8. 3774(3)/14.506(2); b [°] = 90.698(1);
V = 1379.3(3) Å3; dcalcd = 1.325 g cm-3; F(000) = 576; m = 0.195
mm-1; T = 123 K; ω-scan:2.26° < 2θ < 25.25°; 13192 reflections
collected, 4971 independent, 4257 observed (I
> 2s(I));
Rint = 0.108; no absorption correction; diffractometer Stoe IPDS
(Mo-Ka, graphite monochromator); structure solution by direct
methods with SIR97; refinement: full-matrix least-squares on F2
with SHELXL-97, R[I>2s(I)]: R1 = 0.0390, wR2 = 0.0709; R (all
data): R1 = 0.0476, wR2 = 0.0742.
(14) Reddy, V.S.; Katti, K.V.; Barnes, C.L. J. Chem. Soc., Dalton
Trans. 1996, 1301.
(15) Brunner, H.; Pieronczyk, W.; Schönhammer, B.; Streng, K.;
Bernal, I.; Korp, J. Chem. Ber. 1981, 114, 1137.
(16) Brunner, H.; Obermann, U. Chem. Ber. 1989, 122, 499.
(17) Brunner, H.; Kürzinger, A. J. Organomet. Chem. 1988, 346,
413.
X-Ray Structure Analysis of 9
C36H27O4P2∑2CH2Cl2, MW = 727.32; yellow clear plates; crystal
size [mm]: 1.2 × 0.8 × 0.4; space group P 1; triclinic; Z = 2; a/b/c
[Å] = 10.5393(1)/ 12.1436(1)/ 14.1313(1); a/b/g [°] = 72.165(9)/
77.801(1)/79.788(1); V = 1670.4(3) Å3; dcalcd = 1.446 g cm-3;
F(000) = 746; m = 0.490 mm-1; T = 123 K; ω-scan: 2.00° < 2θ <
25.53°; 11656 reflections collected, 4393 independent, 3506 ob-
served (I > 2s(I)); Rint = 0.043; no absorption correction; diffracto-
meter Stoe IPDS (Mo-Ka, graphite monochromator); structure
solution by direct methods with SIR97; refinement: full-matrix
least-squares on F2 with SHELXL-97; R[I>2s(I)]: R1 = 0.0587,
wR2 = 0.153; R (all data): R1 = 0.0717, wR2 = 0.159.
(18) Brunner, H.; Deml, I.; Dirnberger, W.; Ittner, K.P.; Reißer,
W.; Zimmermann, M. Eur. J. Inorg. Chem. 1999, 51.
(19) Brunner, H.; Fürst, J.; Nagel, U.; Fischer, A. Z. Naturforsch.,
B: Chem. Sci. 1994, 1305.
(20) Kagan, H.B.; Dang, T.P. J. Am. Chem. Soc. 1972, 94, 6429.
(21) Brunner, H.; Pieronczyk, W. Angew. Chem. 1979, 91, 655;
Angew. Chem. Int. Ed. 1979, 18, 620.
(22) In the original work an excess of H2SiPh2 was used leading to
28% ee: Dumont, W.; Poulin, J. C.; Dang, T.-P.; Kagan, H.B.
J. Am. Chem. Soc. 1973, 95, 8295.
(23) Hellwinkel, D.; Krapp, W. Chem. Ber. 1978, 111, 13.
(24) Kyba, E.P.; Liu, S.-T.; Harris, R.L. Organometallics 1983, 2,
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Acknowledgement
(25) Kyba, E.P.; Kerby, M.C.; Rines, S.P. Organometallics 1986,
5, 1189.
We thank the Bayerischer Forschungsverband Katalyse (FORKAT)
and the Fonds der Chemischen Industrie for support of this work.
Article Identifier:
1437-210X,E;1999,0,10,1776,1784,ftx,en;Z03299SS.pdf
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