New optically active 'constrained-geometry' cyclopentadienyl-phosphine ligands and their metal complexes

Article abstract of DOI:10.1016/S0022-328X(02)01732-1

Optically active cyclopentadienyl-phosphine ligands were prepared by stereoselective ring opening of spirocyclopentadienes. Optically active metal complexes were made from these new bidentate ligands. A new stereogenic center at rhodium was generated by oxidative addition reactions with high stereoselectivity. The absolute configuration of the major isomer of one rhodium complex was determined by a X-ray structure analysis.

Full text of DOI:10.1016/S0022-328X(02)01732-1

Journal of Organometallic Chemistry 663 (2002) 183ꢁ191
/
www.elsevier.com/locate/jorganchem
New optically active ‘constrained-geometry’ cyclopentadienyl-
phosphine ligands and their metal complexes
Santiago Ciruelos, Angelino Doppiu, Ulli Englert, Albrecht Salzer ꢀ
Institut fur Anorganische Chemie, Technische Hochschule Aachen, Professor-Pirlet-Strasse 1, RWTH Aachen, D-52056 Aachen, Germany
¨
Received 4 June 2002; accepted 18 July 2002
Dedicated to Professor Pascual Royo Gracia.
Abstract
Optically active cyclopentadienyl-phosphine ligands were prepared by stereoselective ring opening of spirocyclopentadienes.
Optically active metal complexes were made from these new bidentate ligands. A new stereogenic center at rhodium was generated
by oxidative addition reactions with high stereoselectivity. The absolute configuration of the major isomer of one rhodium complex
was determined by a X-ray structure analysis.
# 2002 Elsevier Science B.V. All rights reserved.
Keywords: Constrained-geometry; Cyclopentadienyl-phosphine ligands; Rhodium
1. Introduction
catalysis. A cyclopentadienyl-phosphine ligand, con-
nected by an appropriate linker, acts as a 6ꢂ2 electron
ligand and forms a stable chelate ring with both early
/
Chelating ligands containing both a cyclopentadienyl
and a heteroatom have received considerable attention
in recent years. A special attraction of this kind of ligand
is the possibility to vary its three structural components
independently, namely the cyclopentadienyl ring, the
hydrocarbon linker and the heteroatom and its sub-
stituents. The heteroatom can be a hard nucleophile
such as oxygen and nitrogen, but also a soft nucleophile
such as phosphorus, arsenic or sulfur. Both classes of
bidentate ligands and their metal complexes have
recently been reviewed [1,2]. The increased interest in
these ligands is in part due to their application as so-
called ‘constraint-geometry’ catalysts (CGC) in indus-
and late transition metals [2].
Additionally, chirality introduced into systems in
which phosphorus is coordinated to the metal may
assist in controlling the stereochemistry of reactions at
the metal center, ultimately leading to an increase in
stereoselection in stoichiometric and catalytic reactions.
This may be dependent on the spatial proximity of the
stereogenic center(s) to the metal, the rigidity of the
chelate ring as well as the shape of the chiral ‘pocket’
created by it.
Although recent reports of such compounds have
appeared in the literature in which the highly selective
formation of new stereogenic centers at the transition
metal have been presented [4,5], there still remains a
dearth of general procedures to prepare suitable ligands
by a method that allows their modular construction by
independent variation of the three components. We have
recently reported such a route in a preliminary commu-
nication [6] by adapting the method of Kauffmann for
ring-opening substituted spiro[2,4]hepta-4,6-dienes [7].
trial ZieglerꢁNatta catalysis [3]. Among the possible
/
heteroatoms, phosphorus has been receiving growing
interest in view of the general importance of phosphine
ligands in organometallic chemistry and homogeneous
ꢀ Corresponding author. Tel.: ꢂ
8288
E-mail address: albrecht.salzer@ac.rwth-aachen.de (A. Salzer).
/
49-241-804-646; fax: ꢂ49-241-888-
/
0022-328X/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 2 - 3 2 8 X ( 0 2 ) 0 1 7 3 2 - 1

184
S. Ciruelos et al. / Journal of Organometallic Chemistry 663 (2002) 183ꢁ191
/
2. Discussion
a spiroannelated indene as reported by Rieger [9]
should lead to ligands combining both central and
planar chirality. Alternatively, opening reactions
with chiral nucleophiles might produce ligands
which contain additional chiral information within
the nucleophile.
A convenient approach to chiral derivatives of
spirocyclopentadienes starts from optically active 1,2-
diols. We started our investigation with (R)-1-pheny-
lethane-1,2-diol, [(R)-1], which was converted into the
bismethansulfonate ester (R)-2 in quantitative yield.
Displacement of the methansulfonate groups by cy-
d) According to Kauffmann’s protocol, the length of
the spacer between cyclopentadienyl ring and phos-
phorus can also be modified by changing the length
of the diol-precursor. The scope of the nucleophile
should also allow for considerable variation as
many secondary phosphines are available.
clopentadieneꢁNaNH2 formed the spiroannulated diene
/
(S)-3. Both carbons in (R)-2 undergo inversion. The
ring opening reaction of (S)-3 with LiPPh2 proceeds
with complete regioselectivity at the substituted carbon
atom of the cyclopropane ring, bringing the stereogenic
center close to the phosphorus atom.
A related route, starting from chiral styrene epoxide,
which was ring-opened with indenyllithium, has also
recently been reported by Whitby [8]. As fas as we know,
the only precedent for a similar ring opening of a chiral
(but racemic) substituted spiro[2,4]hepta-4,6-diene was
reported by Rieger in a reaction sequence to synthesize
unsymmetrical ansa-indenyl and -fluorenyl ligands with
chiral ethylene bridges [9].
The ring-opening reaction of (S)-3 with LiPPh2
proceeds with complete inversion of configuration at
the stereogenic center as was proven by an X-ray
structure of the rhodium complex (S)-5a [6] (Scheme 1).
This synthetic pathway is very general and should
allow the synthesis of a wide variety of derivatives for
the following reasons:
We have reacted the lithium salt (S)-4 with some
metal precursors, as reported in the preliminary com-
munication. In particular, we have prepared the rho-
dium complexes (S)-5 and (S)-7. We have also treated
(S)-3 with LiP(o-tolyl)2 and LiP(cyclohexyl)2 to give
(S)-4b and (S)-4c, respectively. These were treated with
[Rh(C2H4)2Cl]2 and gave (S)-5b and (S)-5c.
A major goal in preparing these complexes with chiral
chelating ligands was their application in stereoselective
stoichiometric and catalytic reactions. As a model
reaction to explore the efficiency in which the chiral
ligand controlled the stereochemistry at the metal center
we chose the oxidative addition of methyl iodide. It had
been shown in several examples that almost complete
control of diastereoselectivity was achieved by chiral
Cp-linked phosphines [11,12]. We reacted the rhodium
complexes (S)-5aꢁ(S)-5c and (S)-7 with methyl iodide
at room temperature (Scheme 2).
The best diastereoselectivity was observed with (S)-6a
and (S)-6b, which both gave a diastereomeric ratio of
93:7. This value is somewhat lower than that reported by
/
a) The chiral precursors, e.g. monosubstituted ethane-
1,2-diols, are easily available in large quantities by
the general Jacobsen route [10].
b) The lithium salt can be used directly for the
synthesis of metal complexes [6] or quenched with
water to the corresponding cyclopentadiene or with
(CH3)3SiCl to the trimethylsilylderivative [2]. If
desired, the phosphine can at that stage be protected
by the BH3 group.
Tani for his ‘third generation’ Cp?Ã
/
P ligands [11]. This
may possibly be due to the fact that the Tani ligands
exhibit planar chirality as they are derived from indene
and have in some cases additional neomenthyl substi-
tuents. Indenyl ligands, however, have the serious
disadvantage that metal complexation invariably leads
to diastereomers which have to be separated.
c) The method can be combined with other ways to
introduce chirality into the ligands. Ring opening of
Fig. 1. Displacement ellipsoid plot of (SRh,SC)-6a (Platon98, A.L.
Spek, University of Utrecht; 50% probability, H atoms omitted).
Scheme 1.

S. Ciruelos et al. / Journal of Organometallic Chemistry 663 (2002) 183ꢁ
/191
185
Scheme 2.
tion. We are as yet unable to assign the configuration of
the major isomer.
To explore further routes into Cp-linked phosphines,
we also prepared a spiro-cyclopentadiene with a doubly
substituted linker from commercially available (R,R)-
butanediol. Treatment of the dimesylate (R,R)-9 with
cyclopentadieneꢁNaNH2 gave good yields of (S,S)-10,
/
which was ring-opened with LiPPh2 to give the lithium
salt (R,R)-11. Treatment with Re(CO)5Br gave good
yields of the rhenium complex (R,R)-12, which was
protected with BH3 (Scheme 3).
Fig. 2. Graphical summary of one of the two independent molecules
of (R,R)-12.
Unfortunately, the single crystals obtained after
recrystalization from hexane were of relatively poor
quality and no details of the structure will be reported or
deposited. A graphical summary of one of the two
similar independent molecules is shown in Fig. 2.
(R,R)-11 was also reacted with [Rh(C2H4)2Cl]2 to
produce complex (R,R)-13 and reacted with methyl
iodide (Scheme 4). The two isomers were formed in a
The major isomer of (S?)-6a was isolated in pure form
by recrystalization and single crystals were grown from
CH2Cl2ꢁhexane. The X-ray structure is shown in Fig. 1
/
and confirms the stereochemical assignment as (SRh,SC).
We also prepared the carbonyl complex (S)-7 from
[Rh(CO)2Cl]2 to (S)-4a. Reaction with methyl iodide
gave the acetyliodo complex (SRh,SC)-8 and its diaster-
eomer (RRh,SC)-8 in a ratio of 91:9. Again, the major
isomer could be isolated in pure form by recrystaliza-
ratio of 90:10, deꢃ80%. The major isomer could be
/
obtained in pure form by recrystalization. It was not
possible to assign a definite configuration to both
diastereomers.
Scheme 3.

186
S. Ciruelos et al. / Journal of Organometallic Chemistry 663 (2002) 183ꢁ191
/
3.1. (S)-[Rh(h2-C2H4)(h5-h1-C5H4CH2CHPhPPh2)]
(5a)
A suspension of [Rh(C2H4)2Cl]2 (205 mg, 0.53 mmol)
in 15 ml of Et2O was treated with (S)-4a (382 mg, 1.06
mmol) dissolved in 20 ml of THF. The reaction mixture
was stirred for 1 h, leading to a redꢁ
which was evaporated to dryness. Then the residue,
dissolved in a hexaneꢁtoluene mixture (1:1) was eluted
/brownish solution
/
and filtered through a 5 cm pad of alumina. The solvent
was evaporated and the product (S)-5a was obtained by
cooling a saturated hexane solution at ꢄ40 8C (378 mg,
/
0.78 mmol, 74%). 31P-NMR (202 MHz, C6D6): d ꢂ
/
92.4
216.7 Hz, PPh2). 1H-NMR (500 MHz,
Scheme 4.
1
(d, JPÃRh
ꢃ
/
C6D6): d 1.78 (br, 2H, C2H4), 2.33 (m, 1H, CH2), 2.43
(m, 1H, CH2), 2.82 (br, 2H, C2H4), 4.60 (m, 1H, CHPh),
4.99 (m, 1H, Cp), 5.34 (m, 1H, Cp), 5.80 (m, 1H, Cp),
Our experiments with the oxidative addition of methyl
iodide have shown that a very good diastereoselectivity
can be achieved with the chelating ligands developed by
us. Further experiments will be necessary to optimize
them. We are currently preparing spiro compounds
based on indene and fluorene and will introduce other
more bulky phosphorus nucleophiles to optimize the
chiral environment of our ligands to such an extend that
complete control of the chiral metal center becomes
possible.
5.83 (m, 1H, Cp), 6.48ꢁ
NMR (125 MHz, C6D6): d 27.7 (br, C2H4), 29.75 (d,
2JCÃP
7.7 Hz, CH2), 31.9 (br, C2H4), 66.25 (dd,
1JCÃP
Cp), 85.36 (CH, Cp), 85.57 (CH, Cp), 91.60 (CH, Cp),
103.31 (Cipso, Cp), 126.80 (d, JCÃP 2.2 Hz, CH, Ph),
127.22 (d, JCÃP 9.9 Hz, CH, Ph), 128.91 (d, JCÃP
Hz, CH, Ph), 129.14 (dd, JCÃP
Hz, Cipso, PPh2), 130.52 (d, JCÃP
131.95 (d, JCÃP 9.3 Hz, CH, Ph), 133.15 (dd, JCÃP
1.6 Hz, Cipso, PPh2), 137.97 (d,
13.2 Hz, CH, Ph), 138.12 (Cipso, CHPh), (other
/
7.61 (m, 15H, Ph). 13C{1H}-
ꢃ
/
2
ꢃ
/
20.3 Hz, JCÃRh
ꢃ2.2 Hz, CHPh), 81.44 (CH,
/
ꢃ
/
ꢃ
/
ꢃ
/
2.2
1
2
ꢃ
/
35.1 Hz, JCÃRh
ꢃ
/
1.7
ꢃ1.6 Hz, CH, Ph),
/
1
ꢃ
/
ꢃ
/
2
34.5 Hz, JCÃRh
ꢃ
/
JCÃP
ꢃ
/
3. Experimental
signals in the aryl area are overlapped by the C6D6).
Anal. Calc. for C27H26PRh: C, 66.95; H, 5.41. Found:
C, 67.17; H, 5.50%. MS: m/z [assignment, Rint (%)]: 484
All reactions were carried out under nitrogen using
standard Schlenck techniques. Solvents were dried and
deoxygenated by standard methods. NMR spectra were
[Mꢂ, 18]; 456 [(Mꢄ
/
C2H4)ꢂ, 100]; 270 [(Mꢄ
/
C2H4ꢄ
/
PPh2H)ꢂ, 42].
1
recorded on a Varian Mercury 200 (200MHz, H; 50
MHz, 13C; 81 MHz, 31P) and a Varian Unity 500 (500
3.2. (SRh,SC)-[Rh(CH3)(h5-h1-C5H4CH2CHPhP-
Ph2)I] (6a)
1
MHz, H; 125 MHz, 13C; 202 MHz, 31P) at ambient
temperature. 1H and 13C Chemical shifts (d) are given in
ppm relative to SiMe4, 31P relative to H3PO4. Mass
spectra were obtained with a Finnigan MAT 95 spectro-
meter. Elemental analyses were obtained on a Carlo
Erba Strumentazione element analyzer, Model 1106.
(R,R)-2,3-butanediol (Strem), methanesulfonyl chloride
(Fluka), NaNH2 (Merck), LinBu (1.6 M in hexane,
Excess amount of methyl iodide (78 ml, 1.24 mmol)
was added to a solution of (S)-5a (101 mg, 0.21 mmol)
in 20 ml of THF. The reaction mixture was stirred for 12
h, leading to a deep red solution which was evaporated
to dryness. Then the residue, dissolved in CH2Cl2, was
eluted and filtered through a 5 cm pad of alumina. The
solvent was evaporated to afford a diastereomeric
Aldrich), BH3×
/
THF (1.0 M in THF, Aldrich), PPh2H,
PCy2H, and P(o-Tol)2H (Strem) were used as pur-
chased. Monomeric C5H6 was obtained from commer-
cial dicyclopentadiene (Fluka) by dropping into hot
decaline and distilling off through a Vigreux column and
mixture (115 mg, 92% yield, majorꢁ
/
minorꢃ
/
93:7, 86%
de; the ratio was determined by 31P-NMR). Recrystali-
zation of the crude product from CH2Cl2ꢁhexane gave
/
crystals of the title compound in 34% yield. 31P-NMR
1
was stored under nitrogen at ꢄ80 8C. NEt3 (Merck)
/
(202 MHz, CDCl3): d ꢂ
/
84.3 (d, JPÃRh
ꢃ/168.5 Hz,
1
˚
was distilled before use and stored over 4 A molecular
sieves. The syntheses of the compounds (R)-1, (R)-2,
(S)-3 and (S)-4a was published in the preliminary
communication previous to this paper [6]. [Re(CO)5Br]
[13], [Rh(C2H4)2Cl]2[14] and [Rh(CO)2Cl]2[14] were
prepared by published methods.
PPh2, major), ꢂ81.9 (d, JPÃRh
/
ꢃ
/170.3 Hz, PPh2,
1
minor). H-NMR (500 MHz, CDCl3, only the major
diastereoisomer): d 0.94 (m, 3H, RhMe), 2.53 (m, 1H,
CH2), 2.68 (m, 1H, CH2), 4.65 (m, 1H, CHPh), 4.85 (m,
1H, Cp), 5.58 (m, 1H, Cp), 5.72 (m, 1H, Cp), 6.15 (m,
1H, Cp), 6.57ꢁ
7.53 (m, 15H, Ph). 13C{1H}-NMR (125
/

S. Ciruelos et al. / Journal of Organometallic Chemistry 663 (2002) 183ꢁ
/191
187
MHz, CDCl3, only the major diastereoisomer): d ꢄ
/
by the C6D6). Anal. Calc. for C29H30PRh: C, 67.97; H,
5.90. Found: C, 67.17; H, 5.86%. MS: m/z [assignment,
Rint (%)]: 512 [Mꢂ, 15]; 484 [(MꢄC2H4)ꢂ, 100]; 270
[(MꢄC2H4ꢄ
P(o-Tol)2H)ꢂ, 37].
1
2
13.70 (dd, JCÃRh
ꢃ
/
20.6 Hz, JCÃP
ꢃ
/
9.9 Hz, RhMe),
1
2
29.69 (d, JCÃP
Hz, CHPh), 76.48 (CH, Cp), 85.98 (CH, Cp), 93.82
ꢃ
/
6.1 Hz, CH2), 63.54 (d, JCÃP
ꢃ
/
23.6
/
/
/
(CH, Cp), 100.11 (CH, Cp), 111.38 (Cipso, Cp), 127.40
(d, JCÃP
CH, Ph), 127.92 (d, JCÃP
JCÃP 9.5 Hz, CH, Ph), 128.71 (d, JCÃP
Ph), 129.14 (dd, 1JCÃP 35.1 Hz, 2JCÃRh
PPh2), 130.24 (d, JCÃP
JCÃP 2.7 Hz, CH, Ph), 132.28 (d, JCÃP
Ph), 135.69 (dd, 1JCÃP 34.5 Hz, 2JCÃRh
PPh2), 138.11 (d, JCÃP
ꢃ
/
2.2 Hz, CH, Ph), 127.49 (d, JCÃP
1.6 Hz, CH, Ph), 128.12 (d,
3.8 Hz, CH,
ꢃ
/
2.3 Hz,
3.5. (SRh,SC)-[Rh(CH3)(h5-h1-C5H4CH2CHPhP(o-
Tol)2)I] (6b)
ꢃ
/
ꢃ
/
ꢃ
/
ꢃ
/
ꢃ
/
1.7 Hz, Cipso
,
The same procedure described to prepare (RRh,SC)-6a
using (S)-5b (121 mg, 0.24 mmol) and excess MeI (89 ml,
1.44 mmol) afforded a diastereomeric mixture (136 mg,
ꢃ2.2 Hz, CH, Ph), 131.43 (d,
/
ꢃ
/
ꢃ
/
7.7 Hz, CH,
,
ꢃ
/
ꢃ
/
1.6 Hz, Cipso
92% yield, majorꢁ
determined by 31P-NMR). Recrystalization of the crude
product from CH2Cl2ꢁhexane gave crystals of the title
compound in 38% yield. 31P-NMR (202 MHz, CDCl3):
d ꢂ 166.6 Hz, PPh2, major), ꢂ80.7 (d,
83.3 (d, 1JPÃRh
1JPÃRh
170.3 Hz, PPh2, minor). H-NMR (500 MHz,
/
minorꢃ
/
93:7, 86% de; the ratio was
ꢃ
/
11.0 Hz, CH, Ph), 139.02
(Cipso, CHPh). Anal. Calc. for C26H25PIRh: C, 52.20;
H, 4.21. Found: C, 51.97; H, 4.37%. MS: m/z [assign-
/
ment, Rint (%)]: 598 [Mꢂ, 28]; 583 [(Mꢄ
/
CH3)ꢂ, 52]; 456
/
ꢃ
/
/
1
[(Mꢄ
/
CH3I)ꢂ, 100].
ꢃ
/
CDCl3, only the major diastereoisomer): d 0,93 (m, 3H,
RhMe), 2.32 (s, 3H, PhMe), 2.38 (s, 3H, PhMe), 2.60
(m, 1H, CH2), 4.58 (m, 1H, CHPh), 4.80 (m, 1H, Cp),
5.53 (m, 1H, Cp), 5.65 (m, 1H, Cp), 6.10 (m, 1H, Cp),
3.3. (S)-[Li(C5H4CH2CHPhP(o-Tol)2)] (4b)
A flask was charged with 40 ml of THF and cooled to
ꢄ
/
60 8C. At this temperature P(o-Tol)2H (0.47 g, 2.19
6.61ꢁ
/
7.44 (m, 13H, Ph). 13C{1H}-NMR (125 MHz,
mmol) and LinBu (1.4 ml, 1.6 M in hexane, 2.23 mmol)
were added. After the reaction mixture had warmed to
room temperature (r.t.), (S)-3 (0.37 g, 2.19 mmol) was
added by syringe. The mixture was stirred overnight.
The solvent was removed and the product (S)-4b was
CDCl3, only the major diastereoisomer): d ꢄ
/
13.49 (dd,
2
1JCÃRh
ꢃ
/
20.6 Hz, JCÃP
ꢃ
/
9.9 Hz, RhMe), 23.17
2
(PhMe), 23.45 (PhMe), 29.12 (d, JCÃP
CH2), 64.48 (d, JCÃP
Cp), 84.35 (CH, Cp), 89.67 (CH, Cp), 97.23 (CH, Cp),
ꢃ7.1 Hz,
/
1
ꢃ/19.5 Hz, CHPh), 78.48 (CH,
1
washed with cold hexane (3ꢅ
/
20 ml) and Et2O (2ꢅ
/
20
ml) and dried in vacuum (0.85 g, 88% yield) and was
109.16 (Cipso, Cp), 126.83 (d, JCÃP
PPh2), 127.35 (d, JCÃP 2.2 Hz, CH, Ph), 128.99 (d,
JCÃP 2.3 Hz, CH, Ph), 129.77 (d, JCÃP 8.8 Hz, CH,
Ph), 130.43 (d, JCÃP 36.2 Hz, Cipso, PPh2), 131,16 (d,
1JCÃP
36.2 Hz, Cipso, PPh2), 131.57 (d, JCÃP 1.6 Hz,
CH, Ph), 132.67 (d, JCÃP 10.4 Hz, CH, Ph), 139.03 (d,
JCÃP 12.5 Hz, CH, Ph), 139.67 (d, JCÃP
Cipso, CHPh), 138.85 (d, JCÃP
ꢃ/32.6 Hz, Cipso,
ꢃ
/
used immediately for the preparations described below.
ꢃ
/
ꢃ
/
1
ꢃ
/
3.4. (S)-[Rh(h2-C2H4)(h5-h1-C5H4CH2CHPhP(o-
Tol)2)] (5b)
ꢃ
/
ꢃ
/
ꢃ
/
2
ꢃ
/
ꢃ
/
10.2 Hz,
2.5 Hz, CMe, Ph),
2.3 Hz, CMe, Ph). Anal. Calc. for
2
The same procedure described to prepare (S)-5a using
(S)-4b (540 mg, 1.39 mmol) and [Rh(C2H4)2Cl]2 (155
mg, 0.39 mmol) gave (S)-5b as an orange crystalline
solid (498 mg, 70% yield). 31P-NMR (202 MHz, C6D6):
ꢃ
/
2
140.62 (d, JCÃP
ꢃ
/
C28H29PIRh: C, 53.69; H, 4.67. Found: C, 53.17; H,
4.73%. MS: m/z [assignment, Rint (%)]: 626 [Mꢂ, 11];
1
1
d ꢂ
/
89.7 (d, JPÃRh
ꢃ
/
216.1 Hz, PPh2). H-NMR (500
611 [(Mꢄ
/
CH3)ꢂ, 40]; 484 [(MꢄCH3I)ꢂ, 100].
/
MHz, C6D6): d 1.90 (br, 2H, C2H4), 1.97 (s, 3H, Me),
2.06 (s, 3H, Me), 2.39 (m, 1H, CH2), 2.49 (m, 1H, CH2),
3.00 (br, 2H, C2H4), 4.62 (m, 1H, CHPh), 5.03 (m, 1H,
Cp), 5.37 (m, 1H, Cp), 5.84 (m, 1H, Cp), 5.88 (m, 1H,
3.6. (S)-[Li(C5H4CH2CHPhPCy2)] (4c)
The same procedure described to prepare (S)-4b using
0.68 g of PCy2H (3.4 mmol), 2.2 ml of LinBu (3.5 mmol)
and 0.57 g of (S)-3 (3.4 mmol) gave (S)-4c as a white
solid (1.00 g, 79% yield).
Cp), 6.58ꢁ
/
7.59 (m, 13H, Ph). 13C{1H}-NMR (125
MHz, C6D6): d 21.15 (Me), 21.25 (Me), 27.5 (br,
2
C2H4), 29.77 (d, JCÃP
ꢃ
/
7.1 Hz, CH2), 31.5 (br,
20.9 Hz, CHPh), 81.38 (CH,
Cp), 85.32 (CH, Cp), 85.63 (CH, Cp), 91.50 (CH, Cp),
1
C2H4), 66.40 (d, JCÃP
ꢃ
/
3.7. (S)-[Rh(h2-C2H4)(h5-h1-C5H4CH2CHPhPCy2)]
(5c)
1
103.31 (Cipso, Cp), 125.95 (d, JCÃP
PPh2), 126.71 (d, JCÃP 1.6 Hz, CH, Ph), 128.43 (d,
JCÃP 2.8 Hz, CH, Ph), 129.04 (d, JCÃP 9.3 Hz, CH,
Ph), 129.89 (d, JCÃP 36.2 Hz, Cipso, PPh2), 132.20 (d,
JCÃP 9.3 Hz, CH, Ph), 138.15 (d, JCÃP 13.1 Hz, CH,
Ph), 138.36 (d, 2JCÃP
9.9 Hz, Cipso, CHPh), 138.85 (d,
2JCÃP
2.7 Hz, CMe, Ph), 140.62 (d, JCÃP
CMe, Ph) (other signals in the aryl area are overlapped
ꢃ
/
35.7 Hz, Cipso,
ꢃ
/
ꢃ
/
ꢃ
/
A suspension of [Rh(C2H4)2Cl]2 (155 mg, 0.39 mmol)
in 15 ml of Et2O was treated with (S)-4c (293 mg, 0,78
mmol) dissolved in 20 ml of THF. The reaction mixture
1
ꢃ
/
ꢃ
/
ꢃ
/
ꢃ
/
was stirred for 1 h, leading to a redꢁ
which was evaporated to dryness. Then the residue,
dissolved in a hexaneꢁtoluene mixture (1:1) was eluted
/brownish solution
2
ꢃ
/
ꢃ2.2 Hz,
/
/

188
S. Ciruelos et al. / Journal of Organometallic Chemistry 663 (2002) 183ꢁ191
/
1
and filtered through a 5 cm pad of alumina. The solvent
was evaporated and the product (S)-5c was obtained by
1JCÃP
CHPh), 79.12 (CH, Cp), 85.57 (CH, Cp), 86.62 (CH,
Cp), 93.45 (CH, Cp), 107.76 (Cipso, Cp), 127.43 (d,
ꢃ
/
13.2 Hz, CH, Cy), 63.37 (d, JCÃP
ꢃ13.6 Hz,
/
cooling a saturated hexane solution at ꢄ40 8C (304 mg,
/
0.61 mmol, 78%). 31P-NMR (202 MHz, C6D6): d ꢂ
/
88.2
210.6 Hz, PPh2). 1H-NMR (500 MHz,
JCÃP
Ph), 128.78 (d, JCÃP
JCÃP 8.8 Hz, CH, Ph), 131.15 (d, JCÃP
Ph), 140.04 (d, JCÃP
ꢃ
/
2.2 Hz, CH, Ph), 128.67 (d, JCÃP
1.6 Hz, CH, Ph), 129.35 (d,
3.3 Hz, CH,
7.6 Hz, Cipso, Ph). Anal. Calc.
ꢃ3.3 Hz, CH,
/
1
(d, JPÃRh
ꢃ
/
ꢃ
/
C6D6): d 1.00ꢁ
/
1.30 (m, 10H, Cy), 1.50ꢁ
/
1.68 (m, 10H,
ꢃ
/
ꢃ
/
2
Cy), 1.91 (m, 1H, Cy), 2.02 (m, 1H, Cy), 2.12 (br, 2H,
C2H4), 2.36 (m, 1H, CpCH2), 2.53 (m, 1H, CpCH2), 2.86
(br, 2H, C2H4), 3.93 (m, 1H, CpCH2CH), 4.75 (m, 1H,
Cp), 5.29 (m, 1H, Cp), 5.62 (m, 1H, Cp), 5.78 (m, 1H,
Cp), 6.98 (m, 2H, Ph), 7.02 (m, 1H, Ph), 7.09 (m, 2H,
Ph). 13C{1H}-NMR (125 MHz, C6D6): d 24.8 (br,
ꢃ
/
for C26H37PIRh: C, 51.16; H, 6.11. Found: C, 50.65; H,
6.19%. MS: m/z [assignment, Rint (%)]: 610 [Mꢂ, 13];
595 [(Mꢄ
/
CH3)ꢂ, 26]; 468 [(MꢄCH3I)ꢂ, 100].
/
3.9. (S)-[Rh(CO)(h5-h1-C5H4CH2CHPhPPh2)] (7)
C2H4), 25.7 (br, C2H4), 26.84 (d, JCÃP
ꢃ12.0 Hz, CH2,
/
Cy), 27.11 (d, JCÃP 9.8 Hz, CH2, Cy), 27.65 (d,
ꢃ
/
A suspension of [Rh(CO)2Cl]2 (101 mg, 0.26 mmol) in
15 ml of Et2O was treated with (S)-4a (192 mg, 0.53
mmol) dissolved in 20 ml of THF. The reaction mixture
was stirred for 2 h, leading to a dark orange solution
which was evaporated to dryness. Then the residue,
JCÃP
JCÃP
JCÃP
ꢃ
/
21.4 Hz, CH2, Cy), 27.66 (CH2, Cy), 27.94 (d,
11.5 Hz, CH2, Cy), 28.07 (CH2, Cy), 28.27 (d,
ꢃ
/
ꢃ
/
1.6 Hz, CH2, Cy), 28.77 (CH2, Cy), 31.02 (CH2,
2
Cy), 32.39 (d, JCÃP
ꢃ5.5 Hz, CH2Cp), 32.69 (d,
/
1JCÃP
CH, Cy), 61.92 (d, 1JCÃP
Cp), 84.29 (CH, Cp), 84.65 (CH, Cp), 91.60 (CH, Cp),
103.89 (Cipso, Cp), 126.90 (d, JCÃP 1.6 Hz, CH, Ph),
128.45 (d, JCÃP 2.8 Hz, CH, Ph), 128.55 (d, JCÃP 1.1
Hz, CH, Ph), 140.04 (d, JCÃP 7.6 Hz, Cipso, Ph),
ꢃ
/
14.8 Hz, CH, Cy), 35.62 (d, JCÃP
ꢃ
/
14.8 Hz,
dissolved in a hexaneꢁtoluene mixture (1:1) was eluted
/
1
ꢃ/15.4 Hz, CHPh), 80.71 (CH,
and filtered through a 5 cm pad of alumina. The solvent
was evaporated and the product (S)-7 was obtained by
ꢃ
/
cooling a saturated hexane solution at ꢄ
71%). 31P-NMR (202 MHz, C6D6): d
1JPÃRh 206.9 Hz, PPh2). 1H-NMR (500 MHz,
/
40 8C (179 mg,
ꢃ
/
ꢃ
/
ꢂ
/
89.4 (d,
2
ꢃ
/
ꢃ
/
(other signals in the aryl area are overlapped by the
C6D6). Anal. Calc. for C27H38PRh: C, 65.32; H, 7.72.
Found: C, 65.93; H, 7.83%. MS: m/z [assignment, Rint
C6D6): d 2.19 (m, 1H, CH2), 2.26 (m, 1H, CH2), 4.52
(m, 1H, CHPh), 5.51 (m, 1H, Cp), 5.56 (m, 1H, Cp),
5.59 (m, 1H, Cp), 5.75 (m, 1H, Cp), 6.44ꢁ7.60 (m, 15H,
/
(%)]: 496 [Mꢂ, 14]; 466 [(Mꢄ
/
C2H4)ꢂ, 100].
Ph). 13C{1H}-NMR (125 MHz, C6D6): d 30.14 (d,
1
2JCÃP
CHPh), 85.13 (CH, Cp), 85.41 (CH, Cp), 89.32 (CH,
ꢃ
/
7.7 Hz, CH2), 68.35 (d, JCÃP
ꢃ19.7 Hz,
/
3.8. (SRh,SC)-[Rh(CH3)(h5-h1-
C5H4CH2CHPhPCy2)I] (6c)
Cp), 91.00 (CH, Cp), 101.90 (Cipso, Cp), 127.26 (d,
JCÃP
Ph), 128.45 (d, JCÃP
1JCÃP
40.6 Hz, Cipso, PPh2), 130.96 (d, JCÃP
CH, Ph), 132.60 (d, JCÃP 10.9 Hz, CH, Ph), 135.24
44.7 Hz, JCÃRh 1.6 Hz, Cipso, PPh2),
137.63 (Cipso, CHPh), 137.74 (d, JCÃP 13.7 Hz, CH,
Ph), (other signals in the aryl area are overlapped by the
ꢃ
/
2.2 Hz, CH, Ph), 127.41 (d, JCÃP
3.3 Hz, CH, Ph), 130.24 (d,
2.1 Hz,
ꢃ
/
10.4 Hz, CH,
The same procedure described to prepare (RRh,SC)-6a
and (RRh,SC)-6b using (S)-5b (100 mg, 0.20 mmol) and
excess MeI (76 ml, 1.21 mmol) afforded a diastereomeric
ꢃ
/
ꢃ
/
ꢃ
/
ꢃ
/
1
2
mixture (98 mg, 80% yield, majorꢁ
/
minorꢃ/66:34, 32%
(dd, JCÃP
ꢃ
/
ꢃ
/
de; the ratio was determined by 31P-NMR). In this case,
attempts to obtain the pure diastereomer by repeated
recrystalization failed. 31P-NMR (202 MHz, CDCl3): d
ꢃ
/
1
2
C6D6), 193.88 (dd, JCÃRh
CO). Anal. Calc. for C26H22OPRh: C, 64.48; H, 4.58.
ꢃ
/
88.8 Hz, JCÃP
ꢃ19 Hz,
/
1
ꢂ
/
84.9 (d, JPÃRh
ꢃ
/
152.0 Hz, PPh2, major), ꢂ
/
82.0 (d,
1JPÃRh
CDCl3, only the major diastereoisomer): d 0.89 (m, 3H,
RhMe), 1.08ꢁ1.41 (m, 10H, Cy), 1.53ꢁ1.97 (m, 10H,
ꢃ
/
166.6 Hz, PPh2, minor). H-NMR (500 MHz,
Found: C, 64.62; H, 4.58%. MS: m/z [assignment, Rint
1
(%)]: 484 [Mꢂ, 41]; 456 [(Mꢄ
/
CO)ꢂ, 100]; 270 [(Mꢄ
/
/
/
COꢄ
/
PPh2H)ꢂ, 59].
Cy), 2.03 (m, 1H, Cy), 2.16 (m, 1H, Cy), 2.42 (m, 1H,
CpCH2), 2.65 (m, 1H, CpCH2), 3,77 (m, 1H,
CpCH2CH), 4.85 (m, 1H, Cp), 5.28 (m, 1H, Cp), 5.43
3.10. [Rh(COMe)(h5-h1-C5H4CH2CHPhPPh2)I] (8)
(m, 1H, Cp), 5.97 (m, 1H, Cp), 7.14 (m, 2H, Ph), 7.29ꢁ
7.43 (m, 3H, Ph). 13C{1H}-NMR (125 MHz, CDCl3,
only the major diastereoisomer): 13.56 (dd,
9.1 Hz, RhMe), 26.42 (d,
11.4 Hz, CH2, Cy), 26.76 (d, JCÃP 10.3 Hz,
CH2, Cy), 26.93 (d, JCÃP 19.4 Hz, CH2, Cy), 27.05
10.4Hz, CH2, Cy), 28.03
2.2 Hz, CH2, Cy), 29.11
/
Excess amount of methyl iodide (177 ml, 2.82 mmol)
was added to a solution of (S)-7 (226 mg, 0.47 mmol) in
CH2Cl2 at r.t. The reaction mixture was stirred for 5 h
and then the solvent was removed in vacuo to afford a
d
ꢄ
/
2
1JCÃRh
JCÃP
ꢃ
/
19.5 Hz, JCÃP
ꢃ
/
ꢃ
/
ꢃ
/
diastereomeric mixture (263 mg, 90% yield, majorꢁ
minorꢃ91:9, 82% de; the ratio was determined by
31P-NMR). Recrystalization of the crude product from
CH2Cl2ꢁhexane gave crystals of the title compound in
41% yield. 31P-NMR (202 MHz, CDCl3): d ꢂ
86.6 (d,
/
ꢃ
ꢃ
ꢃ
/
/
(CH2, Cy), 27.12 (d, JCÃP
(CH2, Cy), 28.56 (d, JCÃP
/
/
/
2
(CH2, Cy), 31.19 (CH2, Cy), 32.57 (d, JCÃP
ꢃ/5.5 Hz,
/
1
1
CH2Cp), 33.45 (d, JCÃP
ꢃ/14.4 Hz, CH, Cy), 36.74 (d,
1JPÃRh
ꢃ
/
184.9 Hz, PPh2, major), ꢂ
/
80.9 (d, JPÃRh
ꢃ
/

S. Ciruelos et al. / Journal of Organometallic Chemistry 663 (2002) 183ꢁ
/191
189
1
170.3 Hz, PPh2, minor). H-NMR (500 MHz, C6D6,
cooled to r.t. overnight, 20 ml of methanol were
carefully added to quench any excess of NaNH2 or
NaCp and then 300 ml of water were added. The layers
were separated and the aqueous layer was extracted with
only the major diastereoisomer): d 1.95 (m, 1H, CH2),
2.01 (m, 1H, CH2), 2.75 (s, 3H, COMe), 4.63 (m, 1H,
CHPh), 5.22 (m, 2H, Cp), 6.33 (m, 1H, Cp), 6.34 (m,
1H, Cp), 6.70ꢁ
/
7.76 (m, 15H, Ph). 13C{1H}-NMR (125
Et2O (3ꢅ
dried over MgSO4 and then the solvent was pumped off
on a rotovap. The residue was distilled (38ꢁ42 8C/17
/
100 ml). The combined organic fraction was
MHz, C6D6, only the major diastereoisomer): d 28.33
2
(d, JCÃP
1JCÃP
23.1 Hz, CHPh), 81.01 (CH, Cp), 85.08 (CH,
Cp), 95.13 (CH, Cp), 105.18 (CH, Cp), 116.73 (Cipso
Cp), 127.67 (d, JCÃP 2.3 Hz, CH, Ph), 127.99 (d,
JCÃP 9.3 Hz, CH, Ph), 128.88 (d, JCÃP 1.6 Hz, CH,
Ph), 130.20 (d, JCÃP 40.4 Hz, Cipso, PPh2), 131.16 (d,
JCÃP 1.6 Hz, CH, Ph), 132.77 (d, JCÃP 9.9 Hz, CH,
Ph), 132.16 (dd, 1JCÃP 44.4 Hz, 2JCÃRh
PPh2), 137.65 (Cipso, CHPh), 138.43 (d, JCÃP
ꢃ
/
4.7 Hz, CH2), 30.49 (COCH3), 65.90 (d,
/
ꢃ
/
mbar) to yield (S,S)-10 as a colorless liquid (8.5 g, 64%).
1H-NMR (500 MHz, CDCl3): d 2.06 (m, 1H, CH2), 2.31
(m, 1H, CH2), 3.32 (m, 1H, CHPh), 1.32 (m, 6H, CH3),
2.00 (m, 2H,CH), 6.25 (m, 1H, Cp), 6.50 (m, 2H, Cp).
These analytical data are in agreement with those
reported for the racemic form of (S,S)-10 [15].
,
ꢃ
/
ꢃ
/
ꢃ
/
1
ꢃ
/
ꢃ
/
ꢃ
/
ꢃ
/
ꢃ
/
1.6 Hz, Cipso
,
ꢃ/13.7 Hz,
3.13. (R,R)-[Li(C5H4CHMeCHMePPh2)] (11)
CH, Ph), (other signals in the aryl area are overlapped
by the C6D6), 226.03 (dd,, 1JCÃRh 28.8 Hz, 2JCÃP
Hz, CO). Anal. Calc. for C27H25OPIRh: C, 51.78; H,
4.02. Found: C, 51.11; H, 4.12%. MS: m/z [assignment,
ꢃ
/
ꢃ
/
7.7
The same procedure described to prepare (S)-4a using
0.9 ml of PPh2H (5.17 mmol), 3.2 ml of LinBu (5.2
mmol) and 646 mg of (S,S)-10 (5.3 mmol) gave (R,R)-
11 as a white solid (1.12 g, 69% yield).
Rint (%)]: 626 [Mꢂ, 2]; 583 [(Mꢄ
/
COMe)ꢂ, 8]; 498
[(Mꢄ
/
I)ꢂ, 51]; 456 [(Mꢄ
/
COMeꢄ
/
I)ꢂ, 100].
3.14. (R,R)-[Re(CO)3(h5-C5H4CHMeCHMePPh2×
BH3)] (12)
/
3.11. (R,R)-2,3-butanediol bis(methanesulfonate) (9)
To a solution of (R,R)-2,3-butanediol (10.0 g, 110.9
mmol) in 200 ml of CH2Cl2 was added NEt3 (31.0 ml,
223.6 mmol). The solution was cooled to 0 8C, and
methanesulfonyl chloride (18.0 ml, 231.8 mmol) in
CH2Cl2 (50 ml) was added dropwise over 1 h. Upon
complete addition, the mixture containing precipitated
salts was allowed to stir at 0 8C for 1 h and then at r.t.
for 2 h. The mixture was then poured into 1 N HCl (250
ml). The layers were separated and the aqueous layer
[Re(CO)5Br] (349 mg, 0.86 mmol) was dissolved in 30
ml of THF and heated to reflux for 4 h. After cooling
this mixture to 0 8C, (R,R)-11 (269 mg, 0.86 mmol),
dissolved in 20 ml of THF, was slowly added. The
resulting solution was stirred 2 h at ambient temperature
and then refluxed for 1 h. After removing of the solvent
in vacuo, the yellow residue was extracted with 25 ml of
toluene, and the extract was filtered over celite. BH3×
/
THF (1.5 ml, 1.5 mmol, 1.0 M solution in THF) was
added to the filtrate. The mixture was stirred at ambient
temperature overnight. The solvent was evaporated and
was extracted with CH2Cl2 (2ꢅ50 ml). The combined
/
organic layers were washed successively with 1N HCl
(50 ml), saturated NaHCO3 (50 ml) and brine (100 ml).
After drying (MgSO4) the solvent was pumped off to
obtain a pale yellow solid (24.5 g, ca. 100%). This crude
product thus obtained was sufficiently pure to be used in
the product (R,R)-12×
saturated hexane solution at ꢄ
31P-NMR (202 MHz, CDCl3): d ꢂ
1H-NMR (500 MHz, CDCl3): d 0.8ꢁ
/
BH3 was obtained by cooling a
40 8C (309 mg, 61%).
20.6 (br, PPh2×BH3).
1.2 (br, 3H, BH3),
/
/
/
/
1
the next step. H-NMR (200 MHz, CDCl3): d 1.46 (m,
6H, CH3), 3.23 (s, 6H, SCH3), 4.78 (m, 2H, CH).
1.08 (m, 3H, CpCMe), 1.17 (m, 3H, CMePPh2), 2.72
(m, 1H, CHPPh2), 3,03 (m, 1H, CpCH), 5.05 (m, 2H,
Cp), 5.26 (m, 2H, Cp), 7.41ꢁ7.50 (m, 6H, Ph), 7.77 (m,
/
3.12. (S,S)-1,2-Dimethyl-spiro[2,4]hepta-4,6-diene
(10)
4H, Ph). 13C{1H}-NMR (125 MHz, CDCl3): d 12.81
2
(CpCMe), 24.16 (d, JCÃP
ꢃ7.1 Hz, CMePPh2), 33.23
/
2
1
(d, JCÃP
ꢃ
/
4.4 Hz, CpCMe), 35.89 (d, JCÃP
ꢃ
/
32.4 Hz,
CPPh2), 81.08 (CH, Cp), 83.28 (CH, Cp), 84.60 (CH,
To a suspension of NaNH2 (9.50 g, 243.5 mmol) in
200 ml of THF was added dropwise at r.t. freshly
cracked cyclopentadiene (15.0 ml, 181.5 mmol). The
addition of the diene was adjusted so as to maintain
gentle reflux (some care needs to be exercised at this
point since occasionally an induction period in the anion
formation was observed). Upon complete addition, the
pink mixture was stirred 1 h and then a solution of
compound (R,R)-9 (24.5 g, 114.4 mmol) in 200 ml of
THF was added dropwise. This addition was accom-
panied by heat evolution. After the reaction mixture had
3
Cp), 86.96 (CH, Cp), 111.99 (d, JCÃP
Cp), 128.33 (Cipso, Ph), 128.75 (d, JCÃP
Ph), 128.79 (d, JCÃP 10.5 Hz, CH, Ph), 128.93 (d,
9.3 Hz, CH, Ph), 129.26 (Cipso, Ph), 131.28 (d,
2.2 Hz, CH, Ph), 131.33 (d, JCÃP 2.2 Hz, CH,
8.3 Hz, CH, Ph), 132.98 (d,
8.8 Hz, CH, Ph), 194.16 (CO). Anal. Calc. for
ꢃ
/
5.5 Hz, Cipso
,
ꢃ/9.9 Hz, CH,
ꢃ
/
JCÃP
JCÃP
ꢃ
/
ꢃ
/
ꢃ
/
Ph), 132.42 (d, JCÃP
ꢃ
/
JCÃP
ꢃ
/
C24H25BO3PRe: C, 48.90; H, 4.28. Found: C, 48.86; H,
4.32%. MS: m/z [assignment, Rint (%)]: 590 [Mꢂ, 2]; 562
[(Mꢄ
/
CO)ꢂ, 8]; 548 [(Mꢄ
/
COꢄ
BH3)ꢂ, 100].
/

190
S. Ciruelos et al. / Journal of Organometallic Chemistry 663 (2002) 183ꢁ191
/
3.15. (R,R)-[Rh(h2-C2H4)(h5-h1-C5H4CHMeCHMe-
PPh2)] (13)
CH, Ph), 128.26 (d, JCÃP
1JCÃP
30.7 Hz, Cipso, Ph), 129.36 (d, JCÃP
Cipso, Ph), 129.97 (d, JCÃP 2.8 Hz, CH, Ph), 131.23 (d,
JCÃP 2.7 Hz, CH, Ph), 131.70 (d, JCÃP 7.1 Hz, CH,
Ph), 138.12 (d, JCÃP 11.0 Hz, CH, Ph). Anal. Calc. for
ꢃ
/
9.9 Hz, CH, Ph), 128.64 (d,
1
ꢃ
/
ꢃ29.9 Hz,
/
ꢃ
/
The same procedure described to prepare (S)-5a and
(S)-5b using (R,R)-11 (270 mg, 0.86 mmol) and
[Rh(C2H4)2Cl]2 (164 mg, 0.42 mmol) gave (R,R)-13 as
a spectroscopically pure, orange oil (258 mg, 70% yield)
ꢃ
/
ꢃ
/
ꢃ
/
C22H25IPRh: C, 48.02; H, 4.58. Found: C, 48.57; H,
4.63%. MS: m/z [assignment, Rint (%)]: 550 [Mꢂ, 19];
that failed to crystallize. 31P-NMR (202 MHz, C6D6): d
408 [(Mꢄ
/
CH3)ꢂ, 44]; 408 [(MꢄCH3I)ꢂ, 100].
/
1
ꢂ
/
79.0 (d, JPÃRh
ꢃ
212.4 Hz, PPh2). 1H-NMR (500
/
MHz, C6D6): d 0.72 (m, 3H, CpCMe), 0.95 (m, 3H,
CMePPh2), 1.9 (br, 2H, C2H4), 2.40 (m, 1H, CHPPh2),
2.9 (br, 2H, C2H4), 3.39 (m, 1H, CpCH), 4.94 (m, 1H,
Cp), 5.27 (m, 1H, Cp), 5.56 (m, 1H, Cp), 5.83 (m, 1H,
4. X-ray structure determination
Intensity data for (SRhSC)-6a were collected on an
ENRAFꢁNonius CAD4 diffractometer, MoꢁKa radia-
tion equipped with incident beam graphite monochro-
Cp), 6.96ꢁ
/
7.15 (m, 8H, Ph), 8.05 (m, 2H, Ph). 13C{1H}-
/
/
NMR (125 MHz, C6D6): d 13.00 (CpCMe), 14.27 (d,
2
2JCÃ-P
CpCMe), 58.53 (d, JCÃP
(CH, Cp), 81.67 (CH, Cp), 84.86 (CH, Cp), 90.58
(CH, Cp), 112.98 (Cipso, Cp), 128.60 (d, JCÃP 2.3 Hz,
CH, Ph), 130.25 (d, JCÃP 2.7 Hz, CH, Ph), 130.67 (d,
JCÃP 8.7 Hz, CH, Ph), 132.84 (d, JCÃP
Cipso, Ph), 134.81 (d, 1JCÃP
35.2 Hz, Cipso, Ph), 137.44
(d, JCÃP 8.8 Hz, CH, Ph), (other signals in the aryl
ꢃ
/
6.9 Hz, CMePPh2), 30.41 (d, JCÃP
ꢃ
/
13.3 Hz,
mator (lꢃ
dimensions 0.46ꢅ
stream of dinitrogen on a glass fiber. Crystal data:
C26H25IPRh, orthorhombic space group P212121, aꢃ
/
0.71073 A), Tꢃ
/
243 K. A red platelet of ca.
˚
1
ꢃ
/
25.2 Hz, CPPh2), 81.32
/
0.36ꢅ
/
0.10 mm3 was mounted in a
ꢃ
/
/
˚
ꢃ
/
10.339(1), bꢃ
/
12.621(2), cꢃ
/
18.051(2) A, Vꢃ
/
2355.3(6)
2u scan mode with
1
3
˚
ꢃ
/
ꢃ
/30.7 Hz,
A , Zꢃ
/
4. 5370 reflections in the v ꢁ
/
ꢃ
/
u B268, 4456 independent data, empirical absorption
/
ꢃ
/
correction by azimuthal scans [16] (minimum relative
transmission 0.734, maximum relative transmission
0.996). Solution with direct methods (SHELXS97 [17]),
area are overlapped by the C6D6). (It was impossible to
obtain a consistent elemental analysis and MS of the
compound due to the fact that it failed to crystallize).
refinement on F2
(SHELXL97 [18]) with anisotropic
displacement parameters for all non-hydrogen atoms
and H atoms in riding geometry. 263 variables, wR2 (all
3.16. [Rh(CH3)(h5-h1-C5H4CHMeCHMePPh2)I]
(14)
data)ꢃ
/
0.1550, R1 (for data with I ꢀ
/
2s(I))ꢃ
/
0.0637,
max/min electron density from final Difference Fourier
ꢄ3
˚
2.11 e A (close to the halogen atom). The
Excess amount of methyl iodide (194 ml, 3.1 mmol)
was added to a solution of (R,R)-13 (271 mg, 0.62
mmol) in 20 ml of THF. The reaction mixture was
stirred for 12 h, leading to a deep red solution which was
evaporated to dryness. Then the residue, dissolved in
CH2Cl2, was eluted and filtered through a 5 cm pad of
alumina. The solvent was evaporated to afford a
1.87 and ꢄ
/
absolute structure of 6a was unambiguously determined;
a Flack enantiomorph polarity parameter of 0.03(5) was
obtained [19].
In the case of (R,R)-12 the crystal quality was low,
and no details of the structure will be reported or
deposited. A graphical summary of one of two similar
independent molecules is provided by Fig. 2.
diastereomeric mixture (287 mg, 84% yield, majorꢁ
minorꢃ90:10, 80% de; the ratio was determined by
31P-NMR). Recrystalization of the crude product from
CH2Cl2ꢁhexane gave crystals of the title compound in
29% yield. 31P-NMR (202 MHz, CDCl3): d ꢂ
75.6 (d,
/
/
/
5. Supplementary material
/
1
1JPÃRh
ꢃ
/
164.8 Hz, PPh2, major), ꢂ
/
65.6 (d, JPÃRh
ꢃ
/
Crystallographic data for the structural analysis has
been deposited with the Cambridge Crystallographic
Data Centre, CCDC no. 187573. Copies of this infor-
mation may be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge CB2
1
168.5 Hz, PPh2, minor). H-NMR (500 MHz, CDCl3,
only the major diastereoisomer): d 0.84 (m, 3H,
CpCMe), 0.89 (m, 3H, RhMe), 1.23 (m, 3H,
CMePPh2), 2.64 (m, 1H, CHPPh2), 3.65 (m, 1H,
CpCH), 4.67 (m, 1H, Cp), 5.49 (m, 1H, Cp), 5.56 (m,
1EZ, UK (Fax: ꢂ44-1223-336033; or e-mail: depos-
/
1H, Cp), 6.10 (m, 1H, Cp), 7.25ꢁ
(m, 2H, Ph). 13C{1H}-NMR (125 MHz, CDCl3, only
the major diastereoisomer): d ꢄ 20.8
13.05 (dd, 1JCÃRh
Hz, 2JCÃP
10.4 Hz, RhMe), 12.64 (CpCMe), 14.63 (d,
2JCÃP
6.6 Hz, CMePPh2), 33.60 (d, JCÃP
CpCMe), 57.53 (d, JCÃP
(CH, Cp), 81.74 (CH, Cp), 90.97 (CH, Cp), 100.50
(CH, Cp), 121.60 (Cipso, Cp), 127.56 (d, JCÃP 10.4 Hz,
/
7.55 (m, 8H, Ph), 8.01
it@ccdc.cam.ac.uk or www: http://www.ccdc.cam.a-
c.uk).
/
ꢃ
/
ꢃ
/
2
ꢃ
/
ꢃ
/
3.3 Hz,
Acknowledgements
1
ꢃ
/
26.9 Hz, CPPh2), 78.15
The authors gratefully acknowledge financial support
by the Deutsche Forschungsgemeinschaft DFG within
ꢃ
/

S. Ciruelos et al. / Journal of Organometallic Chemistry 663 (2002) 183ꢁ
/191
191
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and by the ‘Fonds der Chemischen Industrie’. S.C.
thanks the European Community (‘Training and Mobi-
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