Synthesis and characterization of planar-chiral cydopentadienyliron complexes (S)- and (R)-{η5-[1-Ph2(OH)C-2-Me-4-PhC5H 2]}Fe(CO)2R (R = C≡CPh, Me, SO2Me)

Article abstract of DOI:10.1021/om9810347

The first enantiomerically pure planar-chiral cyclopentadienyliron complexes, (S)- and (R)-η⁵-Cp^cFe(CO)₂R [Cp^c = 1-hydroxydiphenylmethyl-2-methyl-4-phenylcyclopentadienyl; R = C≡CPh (6), Me (8)], in which the locus of chirality is in the cyclopentadienyl center, were synthesized from Cp^aFe(CO)₂I (4a: Cp^a = 1-(-)-menthoxycarbonyl-2-methyl-4-phenylcyclopentadienyl) and Cp^bFe(CO)₂I (4b: Cp^b = 1-(+)-menthoxycarbonyl-2-methyl-4-phenylcyclopentadienyl) and were isolated as a diastereomerically pure form by fractional recrystallization. The molecular structures of 4a and 4b, including the absolute configuration, have been established by an X-ray crystallographic analysis based on the configuration of the (-)- and (+)-menthyl groups.

Full text of DOI:10.1021/om9810347

Organometallics 1999, 18, 3087-3095
3087
Syn th esis a n d Ch a r a cter iza tion of P la n a r -Ch ir a l
Cyclop en ta d ien ylir on Com p lexes (S)- a n d
(R)-{η5-[1-P h 2(OH)C-2-Me-4-P h C5H2]}F e(CO)2R (R )
CtCP h , Me, SO2Me)
Taku Katayama, Yasushi Morimoto, Michiru Yuge, Mitsunari Uno, and
Shigetoshi Takahashi*
The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka,
Ibaraki, Osaka 567-0047, J apan
Received December 21, 1998
The first enantiomerically pure planar-chiral cyclopentadienyliron complexes, (S)- and (R)-
η5-CpcFe(CO)2R [Cpc ) 1-hydroxydiphenylmethyl-2-methyl-4-phenylcyclopentadienyl; R )
CtCPh (6), Me (8)], in which the locus of chirality is in the cyclopentadienyl center, were
synthesized from CpaFe(CO)2I (4a : Cpa ) 1-(-)-menthoxycarbonyl-2-methyl-4-phenylcyclo-
pentadienyl) and CpbFe(CO)2I (4b: Cpb ) 1-(+)-menthoxycarbonyl-2-methyl-4-phenylcyclo-
pentadienyl) and were isolated as a diastereomerically pure form by fractional recrystalli-
zation. The molecular structures of 4a and 4b, including the absolute configuration, have
been established by an X-ray crystallographic analysis based on the configuration of the
(-)- and (+)-menthyl groups.
In tr od u ction
centered chirality or a planar chirality. Most known
optically active organometallic complexes have chiral
ligands such as chiral phosphines and amines, whereas
there are relatively limited examples for the latter two
types of chiral complexes.3-6 Recently planar-chiral
cyclopentadienyl-metal complexes have received atten-
tion because of their potential in catalysis for the
stereoselective polymerization of vinyl monomers.7
Planar-chiral cyclopentadienyl-metal complexes are
advantageous as catalytic and stoichiometric mediators
for asymmetric organic reactions because the electron-
donor/acceptor properties and steric bulk of the cyclo-
pentadienyl ligands are easily altered, as seen in group
4 metallocene derivatives used as stereoselective po-
lymerization catalysts.7 Coordination of a cyclopenta-
dienyl ligand to a metal atom is generally so strong that
there is almost no chance of ligand association resulting
in racemization. Planar chirality in organometallic
complexes arises from the coordination of prochiral
ligands such as unsymmetrically substituted cyclopen-
tadienyls,4 arenes,5 and olefins6 to a metal and is thus
There are a variety of stereoselective organic reactions
including stereoselective polymerizations in which tran-
sition metal complexes act as effective catalytic or
stoichiometric mediators.1 In particular enantioselective
reactions have been attracting much attention in terms
of the asymmetric syntheses of new medical supplies
and new functional materials, and many effective
systems including practical applications have been
established.2 The development of such systems has been
supported by the discovery of new optically active and
reactive organometallic complexes. There are three
types of optically active organometallic complexes: one
bearing chiral ligands and others containing a metal-
(1) See, for example: (a) Davies, S. G. Organotrasition Metal
Chemistry: Applications to Organic Synthesis; Pergamon Press: Ox-
ford, 1982. (b) Cornils, B., Herrmann, W. A., Eds. Applied Homogeneous
Catalysis with Organometallic Compounds; VHC: Weinheim, 1996;
Vols. 1 and 2. (c) Kobayashi, S., Ed. Catalysis in Precision Polymeri-
zation; J ohn Wiley & Sons: Chichester, 1997.
(2) See, for example: (a) Brunner, H. Acc. Chem. Res. 1979, 12, 250.
(b) Noyori, R. Asymmetric Catalysis in Organic Synthesis; Wiley-
Interscience: New York, 1994.
(3) (a) Brunner, H. Adv. Organomet. Chem. 1980, 18, 152. (b)
Uemura, M.; Kobayashi, T.; Isobe, K.; Minami, T.; Hayashi, Y. J . Org.
Chem. 1986, 51, 2859. (c) Fena´ndez, J . M.; Emerson, K.; Larsern, R.
D.; Gladysz, J . A. J . Chem. Soc., Chem. Commun. 1988, 37. (d)
Brookhart, M.; Liu, Y.; Goldman, E. W.; Timmers, D. A.; Williams, G.
D. J . Am. Chem. Soc. 1991, 113, 927. (e) Boone, B. J .; Klein, D. P.;
Mendez, N. Q.; Seyler, J . W.; Arif, A. M.; Gladysz, J . A. J . Chem. Soc.,
Chem. Commun. 1995, 279. (f) Amoroso, A. J .; Arif, A. M.; Gladysz, J .
A. Organometallics 1997, 16, 6032.
(4) (a) Halterman, R. L. Chem. Rev. 1992, 92, 965. (b) Riant, O.;
Samuel, O.; Kagan, H. B. J . Am. Chem. Soc. 1993, 115, 5835. (c)
Giardello, M. A.; Eisen, M. S.; Stern, C. L.; Marks, T. J . J . Am. Chem.
Soc. 1993, 115, 3326. (d) Sawamura, M.; Sasaki, H.; Nakata, T.; Ito,
Y. Bull. Chem. Soc. J pn. 1993, 66, 2725. (e) Li, L.; Decken, A.; Sayer,
B. G.; McGlinchey; Bregaint, P.; Thepot, J .-Y.; Toupet, L.; Hamon, J .-
R.; Lapinte, C. Organometallics 1994, 13, 682. (f) Koelle, U.; Bucken,
K.; Englert, U. Organometallics 1996, 15, 1376. (g) Halterman, R. L.;
Ramsey, T. M. J . Organomet. Chem. 1997, 530, 225. (h) Pasch, B.;
Koelle, U.; Granter, B.; Englert, U. Organometallics 1997, 16, 3950.
(5) (a) Top, S.; J aouen, G.; Baldoli, C.; Buttero. P. D.; Maiorana, S.
J . Organomet. Chem. 1991, 413, 125. (b) Schmalz, H.-G.; Arnold, M.;
Hollander, J .; Bats, J . W. Angew. Chem., Int. Ed. Engl. 1994, 33, 109.
(c) Christian, P. W. N.; Gil, R.; Muniz-Fernandez, K.; Thomas, S. E.;
Wierzchleyski, A. T. J . Chem. Soc., Chem. Commun. 1994, 1569. (d)
Pearson, A. J .; Milletti, M. C.; Zhu, P. Y. J . Chem. Soc., Chem.
Commun. 1995, 853. (e) Rigby, J . H.; Niyaz, N. M.; Sugathapala, P. J .
Am. Chem. Soc. 1996, 118, 8178.
(6) (a) Turnbull, M. M.; Foxman, B. M.; Rosenblum, M. Organome-
tallics 1988, 7, 200. (b) Gree, D. M.; Kermarrec, J . M.; Martelli, J . T.;
Gree, R. L. J . Org. Chem. 1996, 61, 1918. (c) Benyunes, S. A.; Gibson,
S. E. Chem. Commun. 1996, 43. (d) Benyunes, S. A.; Gibson, S. E.;
Peplow, M. A. Chem. Commun. 1996, 1757.
(7) (a) Britinger, H. H. In Transition Metals and Organometallics
as Catalysts for Olefin Polimerization; Kaminsky, W., Sinn, H., Eds.;
Springer-Verlag: Berlin, 1988; p 249. (b) J ordan, R. F. Adv. Organomet.
Chem. 1991, 32, 325. (c) Spaleck, W.; Kuber, F.; Winter, A.; Rohrmann,
J .; Bachmann, B.; Antberg, M.; Dolle, V.; Paulus, E. F. Organometallics
1994, 13, 954.
10.1021/om9810347 CCC: $18.00 © 1999 American Chemical Society
Publication on Web 07/08/1999

3088 Organometallics, Vol. 18, No. 16, 1999
Katayama et al.
Sch em e 1
characteristic of metal complexes. Efforts have been
directed to the synthesis of planar-chiral cyclopentadi-
enyl-metal complexes, and several optically pure ex-
amples with a planar chirality have been isolated;
however, they are limited to exceptionally stable com-
plexes such as ferrocene and cymantrene derivatives.8
Previously we reported the synthesis of planar-chiral
cyclopentadienylcobalt,9 -rhodium,10 and -ruthenium11
complexes and now report the synthesis of planar-chiral
cyclopentadienyliron complexes with a three-legged
“piano stool” structure. Iron complexes with a piano
stool structure are known to exhibit a variety of reac-
tivities in stoichiometric and catalytic reactions.1,12
Indeed, the synthesis and reactivity of the first planar-
chiral olefin-iron complexes, [(η5-C5H5)Fe(CO)2(η2-ole-
fin)]+, in which the locus of planar chirality is the olefin
center, have been studied extensively by Rosenblum and
co-workers,6a who found that these complexes undergo
enantioselective reactions with nucleophiles.13
group, which could be exchanged with chiral alcohols
such as (-)-menthol.9 By this method we prepared chiral
1,2,4-trisubstituted cyclopentadiene derivatives having
a removable chiral auxiliary, as shown in Scheme 1.
Thus, in the presence of a catalytic amount of toluene-
p-sulfonic acid (p-TsOH), 1-ethoxycarbonyl-2-methyl-4-
phenyl-1,3-cyclopentadiene (1), prepared by the intramo-
lecular Wittig reaction, was allowed to react with (-)-
and (+)-menthol in xylene under reflux. The alcohol-
exchange reaction proceeded smoothly to give (-)-
menthyl ester CpaH (2a ) and (+)-menthyl ester CpbH
(2b), respectively, which were purified by chromatog-
raphy on silica and subsequent distillation.
The planar-chiral cyclopentadienyliron complex, Cpa-
Fe(CO)2I (4a ), was synthesized from 2a by a conven-
tional method.17 Heating 2a with pentacarbonyliron in
the presence of 2-norbornene as a hydrogen acceptor
afforded a diastereomeric mixture of the di(carbonyl)-
(cyclopentadienyl)iron dimer, [CpaFe(CO)2]2 (3a ), in a
good yield. Refluxing 3a with iodine in chloroform gave
CpaFe(CO)2I (4a) in an almost quantitative yield (Scheme
2). The analysis of 4a by high-performance liquid
chromatography (HPLC) using a chiral column and 5:95
isopropyl alcohol/hexane as a mobile phase showed that
4a consists of two diastereomers, (S)-4a and (R)-4a , in
Resu lts a n d Discu ssion
Syn th esis a n d Resolu tion of P la n a r -Ch ir a l Di-
(car bon yl)(η5-cyclopen tadien yl)(iodo)ir on . Recently
we reported the optical resolution of racemic planar-
chiral cyclopentadienyl-transition metal complexes by
means of column chromatography using cyclodextrins
and successfully isolated optically pure enantiomers of
a planar-chiral cyclopentadienylrhodium complex.14 At-
tempts to similarly obtain an enantiomerically pure iron
analogue were unsuccessful. As a consequence of this,
we tested a strategy based on resolution of diastereo-
mers involving chiral cyclopentadienes. There are sev-
eral methods for the selective synthesis of multisubsti-
tuted cyclopentadienes, but few for the synthesis of
chiral cyclopentadienes.4,15 Previously, we developed a
convenient route to chiral cyclopentadienes involving an
intramalecular Wittig reaction16 between haloketones
and phosphonium bromides to give selectively 1,2,4-
trisubstituted cyclopentadienes with an ethyl ester
(8) (a) Thomson, J . B. Tetrahedron Lett. 1959, 6, 26. (b) Marquard-
ing, D.; Kusacek, H.; Gokel, G.; Hoffmann, P.; Ugi, I. J . Am. Chem.
Soc. 1970, 92, 5389. (c) Schlo¨gl, K. Top. Stereochem. 1967, 1, 39. (d)
Schlo¨gl, K. J . Organomet. Chem. 1986, 300, 219. (e) Abbenhuis, H. C.
L.; Burckhardt, U.; Gramlish, V.; Martelletti, A.; Spencer, J .; Steiner,
I.; Togni, A. Organometallics 1996, 15, 1614. (f) Garrett, C. E.; Fu, G.
C. J . Am. Chem. Soc. 1998, 120, 7479.
(9) (a) Uno, M.; Ando, K.; Komatsuzaki, N.; Tanaka, T.; Sawada,
M.; Takahashi, S. J . Chem. Soc., Chem. Commun. 1993, 1549. (b) Uno,
M.; Ando, K.; Komatsuzaki, N.; Tsuda, T.; Tanaka, T.; Sawada, M.;
Takahashi, S. J . Organomet. Chem. 1994, 473, 303.
(10) Uno, M.; Ando, K.; Komatsuzaki, N.; Takahashi, S. J . Chem.
Soc., Chem. Commun. 1992, 964.
1
a ratio of 1:1. In the H NMR spectrum of 4a , one set of
resonances due to the 3-proton on a cyclopentadienyl
ring appeared at δ 5.95 and 5.85 with a ratio of 1:1, and
one set of resonances assignable to the 5-proton on a
cyclopentadienyl ring appeared at δ 6.38 and 6.31 with
a ratio of 1:1, indicating that diastereomers (S)-4a and
1
(R)-4a are clearly distinguished by H NMR.
Fractional recrystallization of 4a has been found to
give diastereomerically pure complexes (Scheme 2).
Thus, pure (S)-4a was isolated as dark purple needles
by recrystallization from a mixture of 1:5 diethyl ether/
hexane, while (R)-4a was obtained from the filtrate as
a black oil with 87% diastereomer excess (de). The same
procedure using chiral cyclopentadiene CpbH (2b) bear-
ing a (+)-menthyl group afforded CpbFe(CO)2I (4b), and
fractional recrystallization gave diastereomerically pure
(R)-4b along with (S)-4b in 76% de. The four diastere-
(11) Komatsuzaki, N.; Uno, M.; Kikuchi, H.; Takahashi, S. Chem.
Lett. 1996, 677.
(12) (a) Vargas, R. M.; Theys, R. D.; Hossain, M. M. J . Am. Chem.
Soc. 1992, 114, 777. (b) Seitz, W. J .; Saha, A. K.; Hossain, M. M.
Organometallics 1993, 12, 2604. (c) Bhaduri, D.; Nelson, J . H.; Wang,
T.; J acobson, R. A. Organometallics 1994, 13, 2291. (d) Cicero, R. L.;
Protasiewicz, J . D. Organometallics 1995, 14, 4792. (e) Mahmood, S.
J .; Hossain, M. M. J . Org. Chem. 1998, 63, 3333. (f) Theys, R. D.;
Vargas, R. M.; Wang, Q.; Hossain, M. M. Organometallics 1998, 17,
1333.
(13) (a) Chang, T. C. T.; Rosenblum, M. J . Org. Chem. 1981, 46,
4105. (b) Chang, T. C. T.; Rosenblum, M. J . Org. Chem. 1981, 46, 4626.
(c) Chang, T. C. T.; Rosenblum, M. Tetrahedron Lett. 1983, 24, 695.
(d) Chang, T. C. T.; Rosenblum, M. J . Am. Chem. Soc. 1989, 111, 5252.
(e) Zhen, W.; Chu, K.-H.; Rosenblum, M. J . Org. Chem. 1997, 62, 3344.
(14) Morimoto, Y.; Ando, K.; Uno, M.; Takahashi, S. Chem. Lett.
1996, 887.
1
omers were identified by IR and H and 13C NMR (see
(17) (a) Piper, T. S.; Cotton, F. A.; Wilkinson, G. J . Inorg. Nucl.
Chem. 1955, 1, 165. (b) Piper, T. S.; Wilkinson, G. J . Inorg. Nucl. Chem.
1956, 3, 104. (c) King, R. B.; Stone, F. G. Inorg. Synth. 1963, 7, 110.
(d) Clark, T. J .; Killian, C. M.; Luthra, S.; Nile, T. A. J . Organomet.
Chem. 1993, 462, 247.
(15) J aniak, C.; Schumann, H. Adv. Organomet. Chem. 1991, 33,
291.
(16) Hatanaka, M.; Himeda, Y.; Ueda, I. J . Chem. Soc., Perkin Trans.
1 1993, 2269.

Cyclopentadienyliron Complexes
Organometallics, Vol. 18, No. 16, 1999 3089
Sch em e 2
m er ic P la n a r -Ch ir a l (η5-cyclop en ta d ien yl)d i(ca r -
b on yl)m et h ylir on a n d -et h yn ylir on . Converting
enantiomeric complexes (S)-4a and (R)-4b into enanti-
omers possessing only planar chirality by removing the
chiral auxiliaries, (-)- and (+)-menthyl groups, was
attempted via hydrolysis because the ethyl ester of a
planar-chiral cobalticinium analogue easily undergoes
hydrolysis in acidic media to give a carboxylic acid.18
However a similar treatment of 4 resulted in the
formation of a complex mixture that did not yield a
carboxylic acid derivative. Next we transformed 4 to a
stable acetylide complex, CpaFe(CO)2(CtCR), by the
treatment with an ethynyltin derivative in the presence
of a palladium catalyst in DMF at room temperature.19
Thus, from the reactions of (S)-4a and (R)-4b with
PhCtCSnBu3 we obtained iron acetylides CpaFe(CO)2Ct
CPh ((S)-5a ) and CpbFe(CO)2CtCPh ((R)-5b) in 87 and
88% yield, respectively, as orange solids. Both acetylides
showed a CtC stretching absorption at 2112 cm-1 in
the IR. Signals due to the CtC group in (S)-5a and (R)-
5b appeared at δ 115.3 (R-C) and 92.8 (â-C) in the 13C
NMR. These data as well as the optical rotation and
melting points indicated that (S)-5a and (R)-5b main-
tain their planar chirality and are a pair of iron
acetylide enantiomers (Table 1).
Ta ble 1. P la n a r -Ch ir a l En a n tiom er s
[η5-C5H2(1-CO2R*)(2-Me)(4-P h )]F e(CO)2Y
complex
Y
R*
decomp (°C)
[R]2D5 (deg)a
(S)-4a
(R)-4b
(S)-5a
(R)-5b
(S)-7a
(R)-7b
I
I
(-)-mentyl 136.0-136.5
(+)-mentyl 136.0-136.5
+93 (c 0.073)
-92 (c 0.074)
+164 (c 0.115)
-164 (c 0.157)
+69.3 (c 0.113)
-68.8 (c 0.124)
CtCPh (-)-mentyl 44.0-46.5
CtCPh (+)-mentyl 43.5-45.5
CH3
CH3
(-)-mentyl oil
(+)-mentyl oil
a
In CH2Cl2.
To remove the menthyl group on the cyclopentadienyl
ligand, 5 was reacted with 2.4 equiv of phenyllithium
at -78 °C in ether, which afforded planar-chiral cyclo-
pentadienyliron acetylide complexes, CpcFe(CO)2Ct
CPh, (S)-6 and (R)-6, in 55 and 52%, respectively, from
(S)-5a and (R)-5b (Scheme 3). On reaction with phe-
nyllithium, the menthyl ester group was converted to a
(hydroxy)diphenylmethyl group; the conversion has
been confirmed by IR and NMR. Complex (S)-6 exhibits
an optical rotation with the same absolute value but
opposite sign as (R)-6 (Table 2), indicating (S)-6 and
F igu r e 1. CD spectra of enantiomers (S)-4a and (R)-4b
(in CH2Cl2).
Experimental Section). Complexes (S)-4a and (R)-4b
exhibited almost the same absolute value but an op-
posite sign for the [R]D (Table 1) and showed circular
dichroism (CD) spectra with mirror symmetry (Figure
1), indicating (S)-4a and (R)-4b to be a pair of enanti-
omers. The absolute configuration of the planar-chiral
complexes was established by X-ray structural analyses
(vide infra).
(18) Komatsuzaki, N.; Uno, M.; Shirai, K.; Tanaka, T.; Sawada, M.;
Takahashi, S. J . Organomet. Chem. 1995, 498, 53.
(19) Crescenzi, R.; Sterzo, C. L. Organometallics 1992, 11, 4301.
Rem ove of th e Ch ir a l Au xilia r y on th e Cyclo-
p en ta d ien yl Liga n d a n d Syn th esis of En a n tio-

3090 Organometallics, Vol. 18, No. 16, 1999
Katayama et al.
Sch em e 3a
a
The absolute structures of all the complexes are shown in an S-form.
plexes, CpaFe(CO)2Me, (S)-7a , and CpbFe(CO)2Me, (R)-
7b, as yellow oils in 42 and 40% yield, respectively.
Methyliron complexes (S)-7a and (R)-7b showed signals
due to the Fe-Me at δ 0.13 in 1H NMR and δ -16 in
13C NMR. Complexes (S)-7a and (R)-7b were treated
with phenyllithium to remove the menthyl group, af-
fording planar-chiral cyclopentadienyliron methyl Cpc-
Fe(CO)2Me, (S)-8 and (R)-8, in 64 and 68% yield,
respectively, as orange-yellow crystals. No exchange of
the methyl group on the iron with a phenyl group was
seen. The optical measurements indicated (S)-8 and
(R)-8 to be a pair of enantiomers having only planar
chirarity (Table 2).
Ta ble 2. P la n a r -Ch ir a l En a n tiom er s
[η5-C5H2(1-CP h 2OH)(2-Me)(4-P h )]F e(CO)2R
complex
R
decomp (°C)
[R]2D5 (deg)a
(S)-6
(R)-6
(S)-8
(R)-8
(S)-9
(R)-9
CtCPh
CtCPh
Me
171.5-172.0
171.5-172.0
163.0-164.0
163.0-164.0
192.0-192.5
192.0-192.5
+221 (c 0.102)
-221 (c 0.100)
+126 (c 0.100)
+126 (c 0.105)
+255 (c 0.107)
-255 (c 0.101)
Me
SO2Me
SO2Me
a
In CH2Cl2.
Rea ction of P la n a r -Ch ir a l Di(ca r bon yl)(η5-cy-
clop en ta d ien yl)eth ylir on w ith Su lfu r Dioxid e. The
optically pure complexes (S)-8 and (R)-8 were reacted
with sulfur dioxide by condensing SO2 on solid (S)-8 in
a flask at -78 °C.20 The complex dissolved in the liquid
sulfur dioxide to form a red solution. After 10 min, sulfur
dioxide was slowly evaporated at room temperature to
leave a yellow solid. Purification by alumina chroma-
tography afforded a planar-chiral cyclopentadienyliron
methylsulfinato complex, CpcFe(CO)2SO2Me, (S)-9, in
good yield (Scheme 3). Similar treatment of (R)-8 with
sulfur dioxide gave (R)-9. These methylsulfinato com-
plexes were formed by the insertion of sulfur dioxide
into the iron-methyl bond without racemization of the
planar chirality (Table 2) and were identified by spectral
analyses (see Experimental Section).
F igu r e 2. CD spectra of enantiomers (S)- and (R)-6, 8,
and 9 (in CH2Cl2).
Molecu la r Str u ctu r e of (S)-4a , (R)-4b, a n d (S)-8.
To establish the absolute configuration of planar-chiral
cyclopentadienyliron complexes, X-ray crystallographic
studies of (S)-4a and (R)-4b have been performed.
Recrystallization of (S)-4a and (R)-4b from diethyl
ether/hexane gave dark purple single-crystals suitable
for an X-ray crystallographic analysis. The molecular
structures of (S)-4a and (R)-4b are illustrated in Figure
3 together with atom-labeling schemes. The structural
parameters and crystal data are summarized in Tables
3 and 4, respectively. The cyclopentadienyl rings (C(1)-
(R)-6 to be a pair of enantiomers, which is supported
by the CD spectra as shown in Figure 2. It should be
noted that the chirality in 6 originates from only planar
chirality based on the cyclopentadienyliron moiety.
In the next step, we attempted the synthesis of
reactive planar-chiral iron complexes which may be
useful in organic syntheses. Such complexes may con-
tain iron-alkyl, and we reacted 4 directly with alkyl-
lithium to synthesize planar-chiral iron-alkyl com-
plexes. Thus, we treated (S)-4a and (R)-4b with 1.1
equiv of methyllithium in diethyl ether at -78 °C and
obtained planar-chiral cyclopentadienyliron methyl com-
(20) Bibler, J . P.; Wojicicki, A. J . Am. Chem. Soc. 1966, 88, 4862.

Cyclopentadienyliron Complexes
Organometallics, Vol. 18, No. 16, 1999 3091
F igu r e 3. ORTEP drawings of the molecular structures of (S)-4a (right) and (R)-4b (left) (ellipsoids drawn at 50%
probability level).
Ta ble 3. Str u ctu r a l P a r a m eter s
These also lie in the normal range. The Fe(1)-I(1) bond
lengths of 2.599(1) for (S)-4a and 2.5999(1) for (R)-4b
are in the normal range of related iron iodide com-
plexes.21 The dihedral angles between the Cp ring and
the phenyl ring (C(7)-C(12)) of (S)-4a and (R)-4b are
13.94° and 15.75°, respectively. The coordination geom-
etry of (S)-4a and (R)-4b is best described as a distorted
octahedron with an η5-cyclopentadienyl ligand occupy-
ing three facial coordination sites, C(13)-Fe(1)-I(1),
C(14)-Fe(1)-I(1), and C(13)-Fe(1)-C(14), and inter-
ligand bond angles approximate to 90° ((S)-4a 91.3(3)°,
88.7(3)°, and 91.9(4)°; (R)-4b 91.7(2)°, 88.0(2)°, and 92.9-
(3)°). Based on the known configuration of the (-)-
menthyl group, the absolute configuration around the
Cp-M moiety has been determined to be S for (S)-4a .
Similarly, on the basis of the known configuration of
the (+)-menthyl group, the absolute configuration has
been determined to be R for (R)-4b. Therefore, com-
plexes (S)-5a , (S)-6, (S)-7a , (S)-8, and (S)-9, which are
derived from (S)-4a and exhibit a positive optical
rotation, must possess an S stereochemistry, while (R)-
5b, (R)-6, (R)-7b, (R)-8, and (R)-9 from (R)-4b have an
R configuration.
Similarly, recrystallization of (S)-8 from diethyl ether/
hexane gave orange-yellow single crystals suitable for
an X-ray crystallographic analysis. Figure 4 depicts an
ORTEP drawing of the molecular structure of (S)-8
together with an atom-labeling scheme. The Cp ring
(C(1)-C(5)) is planar and the Fe-C (cyclopentadienyl
ring) distance is in the range 2.098(6)-2.133(7) Å with
an average of 2.116 Å, which is in the normal region
found for an η5-pentamethylcyclopentadienyliron com-
plex.21 The distance between the Cp ring and the Fe
atom is 1.730 Å. This also lies in the normal range. The
Fe(1)-C(28) bond length is 2.058(7) Å and almost the
same value in comparison with the (η5-cyclopentadi-
enyl)iron-methyl complex of 2.066(6) Å.22 The dihedral
angles between the Cp ring and three phenyl rings
(C(7)-C(12), C(16)-C(21), and C(22)-C(27)) are 5.29°,
81.51°, and 71.73°, respectively. The coordination ge-
ometry of (S)-8 is also described as a distorted octahe-
dron. The interligand bond angles, C(13)-Fe(1)-C(28),
C(14)-Fe(1)-C(28), and C(13)-Fe(1)-C(14) are 85.6-
(4)°, 84.6(3)°, and 96.0(4)°, respectively.
(S)-4a
(R)-4b
(S)-8
Distances (Å)
2.599(1)
2.093(7)
2.162(7)
2.144(7)
2.107(7)
2.069(6)
1.772(9)
1.784(9)
1.122(9)
1.091(10)
1.193(8)
1.421(9)
1.409(9)
1.436(8)
1.422(9)
1.428(9)
1.485(9)
1.49(1)
Fe(1)-I(1) or -C(28)
Fe(1)-C(1)
Fe(1)-C(2)
Fe(1)-C(3)
Fe(1)-C(4)
Fe(1)-C(5)
Fe(1)-C(13)
Fe(1)-C(14)
O(1)-C(13)
O(2)-C(14)
O(3)-C(15)
C(1)-C(2)
2.5999(1)
2.093(5)
2.164(5)
2.136(6)
2.106(6)
2.079(5)
1.784(6)
1.780(6)
1.123(7)
1.127(7)
1.186(6)
1.433(7)
1.407(7)
1.445(7)
1.434(7)
1.420(7)
1.489(7)
1.481(7)
1.476(7)
2.058(7)
2.136(6)
2.123(6)
2.103(6)
2.133(7)
2.098(6)
1.753(8)
1.740(8)
1.143(8)
1.151(8)
1.435(8)
1.461(8)
1.422(8)
1.433(8)
1.432(8)
1.417(9)
1.513(9)
1.480(9)
1.459(9)
C(2)-C(3)
C(3)-C(4)
C(4)-C(5)
C(5)-C(1)
C(1)-C(15)
C(2)-C(6)
C(4)-C(7)
1.477(9)
Angles (deg)
91.3(3)
C(13)-Fe(1)-I(1) or
-C(28)
91.7(2)
88.0(2)
85.6(4)
84.6(3)
C(14)-Fe(1)-I(1) or
-C(28)
88.7(3)
C(13)-Fe(1)-C(14)
Fe(1)-C(13)-O(1)
Fe(1)-C(14)-O(2)
C(1)-C(2)-C(3)
C(2)-C(3)-C(4)
C(3)-C(4)-C(5)
C(4)-C(5)-C(1)
C(5)-C(1)-C(2)
C(1)-C(2)-C(6)
C(3)-C(2)-C(6)
C(3)-C(4)-C(7)
C(5)-C(4)-C(7)
C(5)-C(1)-C(15)
C(2)-C(1)-C(15)
C(1)-C(15)-O(3)
91.9(4)
92.9(3)
96.0(4)
176.6(9)
177.7(8)
107.9(6)
109.1(6)
106.6(6)
108.6(6)
107.8(6)
127.1(7)
124.9(6)
126.5(7)
126.6(6)
126.2(6)
125.6(7)
123.1(7)
177.2(6)
178.1(6)
107.0(4)
109.7(4)
106.1(4)
108.4(4)
108.7(4)
131.0(4)
125.2(5)
126.4(5)
127.1(5)
126.6(5)
124.4(5)
123.9(5)
177.6(8)
176.9(7)
106.9(6)
110.4(6)
105.3(6)
110.9(5)
106.5(6)
127.8(6)
125.0(6)
127.9(6)
126.9(5)
127.2(5)
126.3(6)
110.7(5)
Dihedral Angle between Planes (deg)
Cp ring C(1)-C(5)
and phenyl ring
C(7)-C(12)
13.94
15.75
5.29
Distance between Atom and Plane (Å)
Fe(1) and Cp ring
1.733
1.731
1.730
C(1)-C(5)
C(5)) of (S)-4a and (R)-4b are planar and the Fe-C
(cyclopentadienyl ring) distances are in the range 2.069-
(6)-2.162(7) and 2.079(5)-2.164(5) Å with averages of
2.115 and 2.116 Å, respectively, which are in the normal
region found for an η5-pentamethylcyclopentadienyliron
complex.21 The distances between the Cp ring and Fe
atom are 1.733 Å for (S)-4a and 1.731 Å for (R)-4b.
(21) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watoson,
D. G.; Taylor, R. J . Chem. Soc., Dalton. Trans. 1989, S1.
(22) Brunner, H.; Hammer, B. Organometallics 1983, 2, 1595.

3092 Organometallics, Vol. 18, No. 16, 1999
Ta ble 4. Cr ysta l Da ta of (S)-4a , (R)-4b, a n d (S)-8
Katayama et al.
(S)-4a
(R)-4b
(S)-8
empirical formula
molecular weight
color
crystal size (mm)
habit
C
25H29O4IFe
C25H29O4IFe
576.23
C28H24O3Fe
576.23
464.34
dark purple
0.60 × 0.10 × 0.10
prismatic
orthorhombic
P212121 (No. 19)
13.303(2)
24.403(2)
7.621(2)
2473(7)
4
1.547
1160.00
18.84
Rigaku AFC5R
0.71069
graphite
20.0
ω-2θ
8.0
0.70 + 0.35 tan θ
Patterson
4094
2425
280
dark purple
0.50 × 0.23 × 0.05
prismatic
orthorhombic
P212121 (No. 19)
13.310(3)
24.182(4)
7.572(4)
2437(1)
4
1.570
1160.00
19.13
Rigaku AFC5R
0.71069
graphite
-70.0
ω-2θ
8.0
0.58 + 0.30 tan θ
Patterson
3205
2699
280
0.044
0.047
1.24
1.10
-0.69
orange
0.35 × 0.25 × 0.15
prismatic
orthorhombic
P212121 (No. 19)
10.655(1)
22.222(2)
9.934(1)
2352(4)
4
crystal system
space group
a (Å)
b (Å)
c (Å)
V (Å3)
Z value
D(calcd) (g cm-3
F(000)
)
1.311
968.00
µ (cm-1
diffractometer
)
6.67
Rigaku AFC5R
0.71069
graphite
-75.0
λ (Mo KR radiation) (Å)
monochromator
temperature (°C)
scan type
ω-2θ
16.0
0.79 + 0.30 tan θ
Patterson
3047
1985
290
0.051
0.063
1.13
0.33
-0.37
scan rate (deg min-1
scan range (deg)
method
)
no. of reflns measd
no. of obsns (I >3.00σ(I))
no. of variables
R
Rw
0.043
0.049
1.13
0.71
-0.54
goodness of fit
max peak in final diff map (e Å-3
)
)
min peak in final diff map (e Å-3
air. Melting and decomposition points are corrected. 1H and
13C NMR spectra were measured in acetone-d6 or CD3Cl with
SiMe4 as an internal standard and recorded on a J EOL J NM-
LA400 (400 MHz) spectrometer. Chemical shifts are given in
ppm. IR and mass spectra were taken on Perkin-Elmer system
2000 FT-IR and J EOL J MS-600H instruments, respectively.
Optical rotations were measured on
a J ASCO DIP-1000
polarimeter, and a J ASCO J -725 spectropolarimeter was used
for the measurement of CD spectra. Optical purity was
determined by HPLC using a DAICEL chiral cell OD column.
Elemental analyses were performed by the Material Analysis
Center, ISIR, Osaka University. Diethyl ether and THF were
distilled over benzophenone ketyl under argon just before use.
Dichloromethane was dried over calcium hydride and then
distilled. 1-Ethoxycarbonyl-2-methyl-4-phenylcyclopentadiene
(1) and 1-(-)-menthoxycarbonyl-2-methyl-4-phenylcyclopen-
tadiene (2a , [R]D25: -58.9° (c 1.12, acetone)) were prepared by
the method previously reported.9,15 All other chemicals avail-
able commercially were used without further purification.
Syn th esis of 1-(+)-Men th oxycar bon yl-2-m eth yl-4-ph en -
yl-1,3-cyclop en ta d ien e (2b). To a solution of trisubstituted
cyclopentadiene 1 (11.4 g, 50.0 mmol) in xylene (150 mL) were
added (+)-menthol (23.4 g, 150 mmol) and toluene-p-sulfonic
acid (0.30 g, 1.5 mmol). The solution gradually turned from
yellow to black and was refluxed for 5 days by a Soxhlet’s
method using MS 4A. After the reaction mixture was cooled
to room temperature, the solvent was evaporated in vacuo. The
residual oil was added on a column of silica gel and eluted
with a mixture of 1:9 diethyl ether/hexane. Alcohol-exchange
product 2b was isolated from the first yellow band as an
orange-red oil. Then, purification by distillation in vacuo gave
10.0 g (59%) of 2b as an orange-red oil, bp, 190-195 °C; 0.40
mmHg. IR (neat, cm-1): 1693 (CO). Mass (EI): m/z 338 (M+).
1H NMR (400 MHz, CDCl3): δ 0.80 (3H, d, J ) 7.1 Hz,
menthyl-CH3), 0.92 (3H, d, J ) 6.3 Hz, menthyl-CH3), 0.93
(3H, d, J ) 7.3 Hz, menthyl-CH3), 0.87-0.97 (1H, m, men-
thyl-CH), 1.00-1.13 (2H, m, menthyl-CH2), 1.43-1.57 (2H,
m, menthyl-CH2), 1.69-1.74 (2H, m, menthyl-CH2), 1.97 (1H,
quint. d, J ) 6.8 and 2.7 Hz, menthyl-CH), 2.09-2.14 (1H,
m, menthyl-CH), 2.40 (3H, t, J ) 2.4 Hz, Cp-CH3), 3.71 (2H,
t, J ) 2.4 Hz, Cp), 4.82 (1H, td, J ) 10.8 and 4.4 Hz,
F igu r e 4. ORTEP drawing of the molecular structure of
(S)-8 (ellipsoids drawn at 50% probability level).
In conclusion, we have synthesized several novel
planar-chiral cyclopentadienyliron complexes by using
chiral cyclopentadienes and successfully isolated them
in an optically pure form. The molecular structures of
(S)-4a , (R)-4b, and (S)-8 including the absolute configu-
rations have been established by a single-crystal X-ray
structural analysis. The complexes described herein
provide the first examples of optically pure planar-chiral
(η5-cyclopentadienyl)iron complexes with a piano stool
structure in which the locus of planar chirality is the
cyclopentadienyl center.
Exp er im en ta l Section s
Gen er a l. All reactions were carried out under an atmo-
sphere of nitrogen or argon, but the workup was performed in

Cyclopentadienyliron Complexes
Organometallics, Vol. 18, No. 16, 1999 3093
O-menthyl-CH), 6.76 (1H, s, Cp), 7.24-7.28 (1H, m, p-Ph),
Hz, Cp), 6.31 (1H, d, J ) 2.0 Hz, Cp), 7.43-7.48 (3H, m, Ph),
7.75-7.77 (2H, m, Ph). Mass (FAB): m/z 576 (M+).
7.32-7.37 (2H, m, o-Ph), 7.55-7.57 (2H, m, m-Ph). Anal. Calcd
25
Syn th esis a n d Resolu tion of Iod o(η5-1-(+)-m en th oxy-
ca r b on yl-2-m e t h yl-4-p h e n ylcyclop e n t a d ie n yl)d i(ca r -
bon yl)ir on (4b). A mixture of [CpbFe(CO)2]2 (3b) (10.8 g, 12.0
mmol) and iodine (4.57 g, 18.0 mmol) in chloroform (350 mL)
was treated as described for 4a , giving a mixture of diaster-
eomers (S)-4b and (R)-4b as a black-purple solid in 93% yield.
Pure (R)-4b was isolated by recrystallization three times from
5:1 hexane/diethyl ether as black-purple needles (4.84 g, 35%),
while (S)-4b was obtained from the filtrate as a black oil (5.95
g, 43%) with 76% de.
for C23H30O2: C, 81.62; H,8.93. Found: C, 81.80; H,8.83. [R]D
+59.7° (c 1.06, acetone).
:
Syn th esis of Bis(η5-1-(-)-m en th oxyca r bon yl-2-m eth yl-
4-p h en ylcyclop en ta d ien yl)tetr a (ca r bon yl)d iir on (3a ). To
a solution of CpaH (2a ) (20.3 g, 60.0 mmol) in n-octane (200
mL) was added pentacarbonyliron (17.6 g, 90.0 mmol) and
2-norbornene (5.93 g, 63.0 mmol).16 The solution turned from
yellow to black and was refluxed for 16 h. After the reaction
mixture was cooled to room temperature, the solvent was
evaporated under reduced pressure. The residue was then
dissolved in dichloromethane and filtered with a glass filter.
The filtrate was concentrated to 20 mL, and n-hexane was
slowly added. The brown precipitate of 3a thus formed was
collected, washed with hexane, and dried under vacuum: 19.4
g, 72% yield. IR (KBr, cm-1): 1999, 1959 (terminal CO), 1796
(bridging CO), 1714 (ester CO). Mass (FAB): m/z 899 (M+).
Anal. Calcd for C50H58O8Fe2: C, 66.82; H, 6.51. Found: C,
67.01; H, 6.24.
(R)-4b: IR (KBr, cm-1): 2038, 1997 (terminal CO), 1715
1
(ester CO); H NMR (400 MHz, acetone-d6): δ 0.81 (3H, d, J
) 6.8 Hz, menthyl-CH3), 0.92 (3H, d, J ) 7.3 Hz, menthyl-
CH3), 0.94 (3H, d, J ) 7.3 Hz, menthyl-CH3), 0.89-0.99 (1H,
m, menthyl-CH), 1.08-1.21 (2H, m, menthyl-CH2), 1.49-
1.60 (2H, m, menthyl-CH2), 1.71-1.77 (2H, m, menthyl-CH2),
2.04-2.09 (1H, m, menthyl-CH), 2.21 (1H, quint. d, J ) 6.8
and 2.4 Hz, menthyl-CH), 2.54 (3H, s, Cp-CH3), 4.93 (1H,
td, J ) 11.0 and 4.4 Hz, O-menthyl-CH), 5.94 (1H, d, J ) 2.0
Hz, Cp), 6.38 (1H, d, J ) 2.0 Hz, Cp), 7.41-7.47 (3H, m, Ph),
7.76-7.78 (2H, m, Ph). 13C NMR (100 MHz, acetone-d6): δ
14.75, 16.35, 21.31, 22.39 (CH3), 23.63 (menthyl-CH2), 26.54,
32.22 (menthyl-CH), 34.93, 41.85 (menthyl-CH2), 48.10
(menthyl-CH), 75.86 (O-menthyl-CH), 82.43, 85.27, 88.64,
96.73, 108.85 (Cp), 127.51, 129.88 (Ph), 130.31 (p-Ph), 130.95
(ipso-Ph), 164.94 (ester CO), 214.42, 214.56 (terminal CO).
Mass (FAB): m/z 576 (M+). Anal. Calcd for C25H29O4IFe: C,
52.10; H, 5.08; I, 22.02. Found: C, 52.13; H, 4.83; I, 21.83.
(S)-4b: IR (KBr, cm-1): 2039, 1998 (terminal CO), 1715
Syn th esis of Bis(η5-1-(+)-m en th oxyca r bon yl-2-m eth yl-
4-p h en ylcyclop en ta d ien yl)tetr a (ca r bon yl)d iir on (3b). A
mixture of CpbH (2b) (20.3 g, 60.0 mmol), pentacarbonyliron
(17.6 g, 90.0 mmol), and 2-norbornene (5.93 g, 63.0 mmol) in
n-octane (200 mL) was treated as described for 3a . A similar
workup gave 18.3 g (68%) of 3b as a brown powder. IR (KBr,
cm-1): 1999, 1960 (terminal CO), 1795 (bridging CO), 1715
(ester CO). Mass (FAB): m/z 899 (M+). Anal. Calcd for
C
50H58O8Fe2: C, 66.82; H, 6.51. Found: C, 66.93; H, 6.72.
Syn th esis a n d Resolu tion of Iod o(η5-1-(-)-m en th oxy-
ca r bon yl-2-m eth yl-4-p h en ylcyclop en ta d ien yl)d i(ca r bo-
n yl)ir on (4a ). A mixture of [CpaFe(CO)2]2 (3a ) (13.5 g, 15.0
mmol) and iodine (5.71 g, 22.5 mmol) in chloroform (400 mL)
was refluxed for 1.5 h.16 The solvent was removed, and then
the residue was chromatographed on silica gel. After unreacted
iodine was eluted out with 2:1 dichloromethane/hexane, a
black band with dichloromethane was collected to give a
mixture of diastereomers (S)-4a and (R)-4a (15.6 g, 90%). Pure
(S)-4a was isolated by recrystallization three times from 5:1
hexane/diethyl ether as black-purple needles (6.74 g, 39%),
while (R)-4a was obtained from the filtrate as a black oil (6.57
g, 38%) with 87% de.
1
(ester CO). H NMR (400 MHz, acetone-d6): δ 0.81 (3H, d, J
) 6.8 Hz, menthyl-CH3), 0.93 (3H, d, J ) 7.3 Hz, menthyl-
CH3), 0.95 (3H, d, J ) 7.3 Hz, menthyl-CH3), 0.88-1.00 (1H,
m, menthyl-CH), 1.09-1.22 (2H, m, menthyl-CH2), 1.51-
1.61 (2H, m, menthyl-CH2), 1.76 (2H, dt, J ) 13.7 and 3.2
Hz, menthyl-CH2), 2.04-2.10 (1H, m, menthyl-CH), 2.22
(1H, quint. d, J ) 6.8 and 2.4 Hz, menthyl-CH), 2.58 (3H, s,
Cp-CH3), 4.93 (1H, td, J ) 11.0 and 4.4 Hz, O-menthyl-CH),
5.85 (1H, d, J ) 2.0 Hz, Cp), 6.31 (1H, d, J ) 2.0 Hz, Cp),
7.43-7.48 (3H, m, Ph), 7.75-7.77 (2H, m, Ph). Mass (FAB):
m/z 576 (M+).
Syn th esis of (S)-(η5-1-(-)-Men th oxyca r bon yl-2-m eth yl-
4-p h en ylcyclop en t a d ien yl)d i(ca r b on yl)p h en ylet h yn yl-
ir on ((S)-5a ). To a solution of CpaFe(CO)2I [(S)-4a ] (2.31 g,
4.01 mmol) and tri-n-butylstannylethnylbenzene (1.88 g, 4.81
mmol) in DMF (150 mL) was added 5 mol % of (CH3CN)2PdCl2
with stirring.18 The solution immediately turned dark, and the
stirring was continued at ambient temperature. After 18 h,
diethyl ether (200 mL) was added to the reaction mixture,
followed by a saturated aqueous solution (400 mL) of potas-
sium fluoride. The mixture was stirred rapidly for 30 min,
while argon was bubbled through the solution and then filtered
by vacuum suction through a column tube covered with a
Celite pad. The aqueous phase was discarded, the solution was
washed with water, and the aqueous phase was back-extracted
with diethyl ether. The combined ether extracts were dried
over anhydrous sodium sulfate and filtered. Celite (40 g) was
added to the filtrate, and then the mixture was evaporated to
dryness in vacuo. The residue was added to a column of silica
gel and eluted with a mixture of 1:9 hexane/ethyl acetate. The
coupled product, (S)-5a , was isolated from the orange-red band
as an orange solid (1.92 g, 87%). IR (KBr, cm-1): 2112 (CtC),
2039, 1997 (terminal CO), 1715 (ester CO). 1H NMR (400 MHz,
acetone-d6): δ 0.78 (3H, d, J ) 6.8 Hz, menthyl-CH3), 0.87
(3H, d, J ) 7.1 Hz, menthyl-CH3), 0.88 (3H, d, J ) 6.6 Hz,
menthyl-CH3), 0.89-0.94 (1H, m, menthyl-CH), 1.08-1.20
(2H, m, menthyl-CH2), 1.43-1.55 (2H, m, menthyl-CH2),
1.69-1.74 (2H, m, menthyl-CH2), 2.04-2.09 (1H, m, men-
thyl-CH), 2.15 (1H, quint. d, J ) 6.8 and 2.7 Hz, menthyl-
CH), 2.38 (3H, s, Cp-CH3), 4.91 (1H, td, J ) 11.0 and 4.4 Hz,
(S)-4a : IR (KBr, cm-1): 2038, 1997 (terminal CO), 1715
(ester CO). H NMR (400 MHz, acetone-d6): δ 0.81 (3H, d, J
1
) 6.8 Hz, menthyl-CH3), 0.93 (3H, d, J ) 7.3 Hz, menthyl-
CH3), 0.95 (3H, d, J ) 7.3 Hz, menthyl-CH3), 0.88-1.00 (1H,
m, menthyl-CH), 1.09-1.22 (2H, m, menthyl-CH2), 1.51-
1.61 (2H, m, menthyl-CH2), 1.76 (2H, dt, J ) 13.7 and 3.2
Hz, menthyl-CH2), 2.04-2.10 (1H, m, menthyl-CH), 2.22
(1H, quint. d, J ) 6.8 and 2.4 Hz, menthyl-CH), 2.55 (3H, s,
Cp-CH3), 4.93 (1H, td, J ) 11.0 and 4.4 Hz, O-menthyl-CH),
5.95 (1H, d, J ) 2.0 Hz, Cp), 6.38 (1H, d, J ) 2.0 Hz, Cp),
7.42-7.48 (3H, m, Ph), 7.77-7.79 (2H, m, Ph). 13C NMR (100
MHz, acetone-d6): δ 14.74, 16.35, 21.30, 22.38 (CH3), 23.63
(menthyl-CH2), 26.54, 32.22 (menthyl-CH), 34.93, 41.85
(menthyl-CH2), 48.10 (menthyl-CH), 75.86 (O-menthyl-CH),
82.43, 85.27, 88.63, 96.73, 108.85 (Cp), 127.51, 129.87 (Ph),
130.31 (p-Ph), 130.96 (ipso-Ph), 164.94 (ester CO), 214.42,
214.56 (terminal CO). Mass (FAB): m/z 576 (M+). Anal. Calcd
for C25H29O4IFe: C, 52.10; H, 5.08; I, 22.02. Found: C, 51.82;
H, 5.02; I, 22.22.
(R)-4a : IR (KBr, cm-1): 2038, 1997 (terminal CO), 1715
1
(ester CO). H NMR (400 MHz, acetone-d6): δ 0.81 (3H, d, J
) 6.8 Hz, menthyl-CH3), 0.93 (3H, d, J ) 7.3 Hz, menthyl-
CH3), 0.95 (3H, d, J ) 7.3 Hz, menthyl-CH3), 0.91-1.00 (1H,
m, menthyl-CH), 1.10-1.22 (2H, m, menthyl-CH2), 1.51-
1.58 (2H, m, menthyl-CH2), 1.74-1.77 (2H, m, menthyl-CH2),
2.04-2.10 (1H, m, menthyl-CH), 2.22 (1H, quint. d, J ) 6.8
and 2.4 Hz, menthyl-CH), 2.57 (3H, s, Cp-CH3), 4.93 (1H,
td, J ) 11.0 and 4.4 Hz, O-menthyl-CH), 5.85 (1H, d, J ) 2.0

3094 Organometallics, Vol. 18, No. 16, 1999
Katayama et al.
O-menthyl-CH), 5.98 (1H, d, J ) 2.0 Hz, Cp), 6.42 (1H, d, J
) 2.0 Hz, Cp), 7.05-7.10 (1H, m, Ph), 7.16-7.23 (4H, m, Ph),
7.37-7.46 (3H, m, Ph), 7.77-7.80 (2H, m, Ph). 13C NMR (100
MHz, acetone-d6): δ 14.13, 16.40, 21.24, 22.30 (CH3), 23.71
(menthyl-CH2), 26.75, 32.16 (menthyl-CH), 32.16, 41.73
(menthyl-CH2), 48.14 (menthyl-CH), 75.58 (O-menthyl-CH),
83.70, 86.89, 87.47 (Cp), 92.82 (FeCtC), 99.79, 111.29 (Cp),
115.31 (FeCtC), 125.83, 127.32, 128.57 (Ph), 129.53 (ipso-Ph),
129.74, 129.83 (Ph), 131.86 (ipso-Ph), 131.96 (Ph), 165.23 (ester
CO), 212.83, 213.12 (terminal CO). Mass (FAB): m/z 551 (M+).
Anal. Calcd for C33H34O4Fe: C, 72.00; H, 6.23. Found: C, 72.03;
H, 6.10.
Syn th esis of (R)-(η5-1-Hydr oxydiph en ylm eth yl-2-m eth -
yl-4-ph en ylcyclopen tadien yl)di(car bon yl)ph en yleth yn yl-
ir on ((R)-6). To a solution of CpbFe(CO)2CtCPh [(R)-5b]
(0.671 g, 1.22 mmol) in diethyl ether (40 mL) at -78 °C was
added dropwise a solution of 1.8 M phenyllithium (1.6 mL,
2.4 equiv) in 7:3 cyclohexane/diethyl ether. The reaction
mixture was treated as described for (S)-6, yielding 0.349 g
(52%) of (R)-6 as a yellow powder. IR (KBr, cm-1): 2101 (Ct
C), 2040, 1991 (terminal CO). 1H NMR (400 MHz, acetone-
d6): δ 1.98 (3H, s, Cp-CH3), 5.30 (1H, d, J ) 2.0 Hz, Cp), 6.04
(1H, d, J ) 2.0 Hz, Cp), 6.20 (1H, s, OH), 7.15-7.19 (1H, m,
Ph), 7.25-7.29 (2H, m, Ph), 7.30-7.39 (11H, m, Ph), 7.45-
7.47 (2H, m, Ph), 7.56-7.59 (4H, m, Ph). 13C NMR (100 MHz,
acetone-d6): δ 13.71 (Cp-CH3), 78.67 (COH), 87.02, 87.85 (Cp),
93.65 (FeCtC), 96.50, 108.12, 110.20 (Cp), 119.43 (FeCtC),
126.54, 126.80, 127.90, 128.10, 128.20, 128.22, 128.60, 128.75,
128.93, 129.40, 129.74, 131.77 (Ph), 132.26, 146.37, 146.82
(ipso-Ph), 213.42, 213.64 (terminal CO). Mass (FAB): m/z 551
(M+). Anal. Calcd for C35H26O3Fe: C, 76.10; H, 4.81. Found:
C, 76.37; H, 4.76.
Syn th esis of (R)-(η5-1-(+)-Men th oxyca r bon yl-2-m eth yl-
4-p h en ylcyclop en t a d ien yl)d i(ca r b on yl)p h en ylet h yn yl-
ir on ((R)-5b). To a solution of CpbFe(CO)2I [(S)-4b] (1.73 g,
3.00 mmol) and tri-n-butylstannylethnylbenzene (1.41 g, 4.60
mmol) in DMF (150 mL) was added 5 mol % of (CH3CN)2PdCl2
with stirring. After 19 h, the reaction mixture was treated as
discribed for (S)-5a , yielding 1.45 g (88%) of (R)-5b as an
orange powder. IR (KBr, cm-1): 2112 (CtC), 2040, 1997
1
(terminal CO), 1715 (ester CO). H NMR (400 MHz, acetone-
Syn th esis of (S)-(η5-1-(-)-Men th oxyca r bon yl-2-m eth yl-
4-p h en ylcyclop en ta d ien yl)d i(ca r bon yl)m eth ylir on ((S)-
7a ). To a solution of CpaFe(CO)2I [(S)-4a ] (2.31 g, 4.01 mmol)
in diethyl ether (30 mL) at -78 °C was added dropwise a
solution of 1.14 M methyllithium (4.0 mL, 1.15 equiv) in
diethyl ether. The solution was stirred at room temperature
for 3 h. The reaction mixture was quenched with water at -78
°C and extracted with diethyl ether. The ether extracts were
transferred to a chromatographic column packed with silica
gel and eluted with a mixture of 5:1 hexane/diethyl ether. Two
bands were collected. Product (S)-7a was isolated from the first
yellow band as a yellow oil (0.78 g, 42%), and the second black
one was unreacted CpaFe(CO)2I [(S)-4a ] (0.56 g, 24%). IR (KBr,
cm-1): 2015, 1965 (terminal CO), 1714 (ester CO). 1H NMR
(400 MHz, acetone-d6): δ 0.13 (3H, s, Fe-CH3), 0.80 (3H, d, J
) 6.8 Hz, menthyl-CH3), 0.92 (3H, d, J ) 6.8 Hz, menthyl-
CH3), 0.93 (3H, d, J ) 6.6 Hz, menthyl-CH3), 0.91-0.98 (1H,
m, menthyl-CH), 1.07-1.19 (2H, m, menthyl-CH2), 1.49-
1.55 (2H, m, menthyl-CH2), 1.71-1.75 (2H, m, menthyl-CH2),
2.02-2.04 (1H, m, menthyl-CH), 2.07 (1H, quint. d, J ) 6.8
and 2.7 Hz, menthyl-CH), 2.18 (3H, s, Cp-CH3), 4.86 (1H,
td, J ) 11.0 and 4.4 Hz, O-menthyl-CH), 5.59 (1H, d, J ) 2.0
Hz, Cp), 6.02 (1H, d, J ) 2.0 Hz, Cp), 7.30-7.34 (1H, m, Ph),
7.37-7.41 (2H, m, Ph), 7.62 (2H, d, J ) 7.1 Hz, Ph). 13C NMR
(100 MHz, acetone-d6): δ -16.05 (Fe-CH3), 13.14, 16.37,
21.21, 22.35 (CH3), 23.76 (menthyl-CH2), 26.79, 32.21 (men-
thyl-CH), 34.97, 41.88 (menthyl-CH2), 48.17 (menthyl-CH),
75.01 (O-menthyl-CH), 83.52, 87.04, 87.04, 100.55, 107.60
(Cp), 126.81, 129.04, 129.66 (Ph), 133.03 (ipso-Ph), 166.01
(ester CO), 216.93, 216.97 (terminal CO). Mass (FAB): m/z
464 (M+). Anal. Calcd for C26H32O4Fe: C, 67.25; H, 6.95.
Found: C, 67.41; H, 7.02.
Syn th esis of (R)-(η5-1-(+)-Men th oxyca r bon yl-2-m eth yl-
4-p h en ylcyclop en ta d ien yl)d i(ca r bon yl)m eth ylir on ((R)-
7b). To a solution of CpbFe(CO)2I [(R)-4b] (4.61 g, 8.00 mmol)
in diethyl ether (60 mL) at -78 °C was added dropwise a
solution of 1.14 M methyllithium (8.0 mL, 1.15 equiv) in
diethyl ether. The reaction mixture was treated as described
for (S)-6a , yielding 1.49 g (40%) of (R)-6b as a yellow oil and
1.29 g (28%) of unreacted CpbFe(CO)2I. IR (KBr, cm-1): 2014,
1965 (terminal CO), 1714 (ester CO). 1H NMR (400 MHz,
acetone-d6): δ 0.13 (3H, s, Fe-CH3), 0.80 (3H, d, J ) 7.1 Hz,
menthyl-CH3), 0.92 (3H, d, J ) 6.8 Hz, menthyl-CH3), 0.93
(3H, d, J ) 6.6 Hz, menthyl-CH3), 0.91-0.98 (1H, m, men-
thyl-CH), 1.07-1.19 (2H, m, menthyl-CH2), 1.48-1.55 (2H,
m, menthyl-CH2), 1.71-1.76 (2H, m, menthyl-CH2), 2.02-
2.04 (1H, m, menthyl-CH), 2.07 (1H, quint. d, J ) 6.8 and
2.7 Hz, menthyl-CH), 2.18 (3H, s, Cp-CH3), 4.86 (1H, td, J
) 11.0 and 4.4 Hz, O-menthyl-CH), 5.58 (1H, d, J ) 2.0 Hz,
Cp), 6.01 (1H, d, J ) 2.0 Hz, Cp), 7.30-7.34 (1H, m, Ph), 7.37-
7.41 (2H, m, Ph), 7.62 (2H, d, J ) 7.3 Hz, Ph). 13C NMR (100
d6): δ 0.77 (3H, d, J ) 6.8 Hz, menthyl-CH3), 0.87 (3H, d, J
) 7.1 Hz, menthyl-CH3), 0.87 (3H, d, J ) 6.6 Hz, menthyl-
CH3), 0.84-0.89 (1H, m, menthyl-CH), 1.13 (2H, quint, J )
11.8 Hz, menthyl-CH2), 1.48-1.54 (2H, m, menthyl-CH2),
1.69-1.74 (2H, m, menthyl-CH2), 2.04-2.07 (1H, m, men-
thyl-CH), 2.14 (1H, quint. d, J ) 6.8 and 2.7 Hz, menthyl-
CH), 2.37 (3H, s, Cp-CH3), 4.90 (1H, td, J ) 11.0 and 4.4 Hz,
O-menthyl-CH), 5.98 (1H, d, J ) 2.0 Hz, Cp), 6.43 (1H, d, J
) 2.0 Hz, Cp), 7.04-7.09 (1H, m, Ph), 7.12-7.22 (4H, m, Ph),
7.36-7.45 (3H, m, Ph), 7.75-7.81 (2H, m, Ph). 13C NMR (100
MHz, acetone-d6): δ 14.12, 16.39, 21.24, 22.28 (CH3), 23.86
(menthyl-CH2), 26.75, 32.16 (menthyl-CH), 34.93, 41.73
(menthyl-CH2), 48.15 (menthyl-CH), 75.59 (O-menthyl-CH),
83.73, 86.90, 87.49 (Cp), 92.80 (FeCtC), 99.81, 111.27 (Cp),
115.31 (FeCtC), 125.84, 127.32, 128.58 (Ph), 129.54 (ipso-Ph),
129.74, 129.83 (Ph), 131.85 (ipso-Ph), 131.97 (Ph), 165.24 (ester
CO), 212.84, 213.13 (terminal CO). Mass (FAB): m/z 551 (M+).
Anal. Calcd for C33H34O4Fe: C, 72.00; H, 6.23. Found: C, 72.15;
H, 6.22.
Syn th esis of (S)-(η5-1-Hyd r oxyd ip h en ylm eth yl-2-m eth -
yl-4-ph en ylcyclopen tadien yl)di(car bon yl)ph en yleth yn yl-
ir on ((S)-6). To a solution of CpaFe(CO)2CtCPh [(S)-5a ] (0.870
g, 1.58 mmol) in diethyl ether (50 mL) at -78 °C was added
dropwise a solution of 1.8 M phenyllithium (2.1 mL, 2.4 equiv)
in 7:3 cyclohexane/diethyl ether. The temperature was main-
tained at -78 °C, while the solution was stirred for 1 h. Then,
to the solution was added dropwise water (20 mL) at -78 °C,
and the reaction mixture was warmed to room temperature.
The aqueous phase was discarded, the solution was washed
with water, and the aqueous phase was back-extracted with
diethyl ether. The combined ether extracts were dried over
anhydrous sodium sulfate and filtered. The solvent was
evaporated to dryness in vacuo, and (-)-menthol formed was
removed from the residue by sublimation at 50 °C in vacuo.
The residue dissolved in diethyl ether (5 mL) was then
transferred to a chromatographic column packed with silica
gel and eluted with a mixture of 1:9 hexane/diethyl ether. The
product, (S)-6, was isolated as a yellow powder (0.478 g, 55%).
IR (KBr, cm-1): 2101 (CtC), 2039, 1991 (terminal CO). 1H
NMR (400 MHz, acetone-d6): δ 1.98 (3H, s, Cp-CH3), 5.29
(1H, d, J ) 2.0 Hz, Cp), 6.04 (1H, d, J ) 2.0 Hz, Cp), 6.20 (1H,
s, OH), 7.15-7.19 (1H, m, Ph), 7.25-7.29 (2H, m, Ph), 7.31-
7.40 (11H, m, Ph), 7.45-7.47 (2H, m, Ph), 7.56-7.59 (4H, m,
Ph). 13C NMR (100 MHz, acetone-d6): δ 13.71 (Cp-CH3), 78.67
(COH), 87.01, 87.84 (Cp), 93.65 (FeCtC), 96.50, 108.12, 110.19
(Cp), 119.43 (FeCtC), 126.54, 126.79, 127.90, 128.09, 128.20,
128.22, 128.58, 128.75, 128.92, 129.40, 129.74, 131.77 (Ph),
132.25, 146.37, 146.81 (ipso-Ph), 213.41, 213.64 (terminal CO).
Mass (FAB): m/z 551 (M+). Anal. Calcd for C35H26O3Fe: C,
76.10; H, 4.81. Found: C, 76.12; H, 4.70.

Cyclopentadienyliron Complexes
Organometallics, Vol. 18, No. 16, 1999 3095
MHz, acetone-d6): δ -16.00 (Fe-CH3), 13.12, 16.33, 21.20,
22.35 (CH3), 23.70 (menthyl-CH2), 26.74, 32.18 (menthyl-
CH), 34.92, 41.84 (menthyl-CH2), 48.12 (menthyl-CH), 74.93
(O-menthyl-CH), 83.42, 86.96, 87.00, 100.48, 107.61 (Cp),
126.77, 129.01, 129.64 (Ph), 132.99 (ipso-Ph), 165.97 (ester
CO), 216.91, 216.94 (terminal CO). Mass (FAB): m/z 464 (M+).
Anal. Calcd for C26H32O4Fe: C, 67.25; H, 6.95. Found: C, 67.28;
H, 6.71.
as a yellow powder (0.106 g, 89%). IR (KBr, cm-1): 2048, 2001
(terminal CO), 1179 (SO). H NMR (400 MHz, acetone-d6): δ
1
1.94 (3H, s, Cp-CH3), 2.88 (3H, s, SO2CH3), 5.51 (1H, d, J )
2.0 Hz, Cp), 5.91 (1H, d, J ) 2.0 Hz, Cp), 7.21 (1H, s, OH),
7.27-7.41 (9H, m, Ph), 7.47-7.49 (2H, m, Ph), 7.55-7.57 (2H,
m, Ph), 7.67-7.69 (2H, m, Ph). 13C NMR (100 MHz, acetone-
d6): δ 13.85 (Cp-CH3), 58.98 (SO2CH3), 77.80 (COH), 85.20,
88.00, 98.37, 109.88, 111.90 (Cp), 127.53, 127.95, 128.14,
128.14, 128.20, 128.67, 128.76, 129.90, 130.29 (Ph), 130.39,
147.09, 147.19 (ipso-Ph), 211.41, 212.12 (terminal CO). Mass
(FAB): m/z 529 (M+). Anal. Calcd for C28H24O5SFe: C, 63.65;
H, 4.58; S, 6.07. Found: C, 63.85; H, 4.60; S, 5.89.
Syn th esis of (S)-(η5-1-Hyd r oxyd ip h en ylm eth yl-2-m eth -
yl-4-ph en ylcyclopen tadien yl)di(car bon yl)m eth ylir on ((S)-
8). To a solution of CpaFe(CO)2Me [(S)-7a ] (0.470 g, 1.01 mmol)
in diethyl ether (30 mL) at -78 °C was added dropwise a
solution of 1.8 M phenyllithium (1.4 mL, 2.5 equiv) in 7:3
cyclohexane/diethyl ether. The temperature was maintained
at -78 °C, while the solution was stirred for 1 h. Then, to the
solution was added dropwise water (10 mL) at -78 °C, and
the reaction mixture was warmed to room temperature. The
aqueous phase was discarded, and the solution was washed
with water. The ether extracts were dried over anhydrous
sodium sulfate and filtered. The solvent was evaporated to
dryness in vacuo, and (-)-menthol formed was removed from
the residue by sublimation at 50 °C in vacuo. The residue
dissolved in diethyl ether (5 mL) was then transferred to a
chromatographic column packed with silica gel and eluted with
a mixture of 10:1 hexane/diethyl ether. Two bands were
collected, the first of which was unreacted CpaFe(CO)2Me
(0.093 g, 20%); the second one is product. (S)-8 was isolated
by recrystallization from a mixture of diethyl ether-hexane
as orange-yellow crystals (0.299 g, 64%). IR (KBr, cm-1): 1997,
1935 (terminal CO). 1H NMR (400 MHz, acetone-d6): δ -0.03
(3H, s, Fe-CH3), 1.89 (3H, s, Cp-CH3), 4.72 (1H, d, J ) 2.0
Hz, Cp), 5.26 (1H, d, J ) 2.0 Hz, Cp), 5.31 (1H, s, OH), 7.21-
7.24 (1H, m, Ph), 7.28-7.38 (10H, m, Ph), 7.41-7.44 (2H, m,
Ph), 7.47-7.49 (2H, m, Ph). 13C NMR (100 MHz, acetone-d6):
δ -17.65 (Fe-CH3), 13.55 (Cp-CH3), 78.74 (COH), 87.44,
90.39, 94.92, 101.38, 110.42 (Cp), 126.31, 128.07, 128.09,
128.18, 128.26, 128.44, 128.44, 128.70, 129.43 (Ph), 133.68,
147.13, 147.24 (ipso-Ph), 218.35, 218.89 (terminal CO). Mass
(FAB): m/z 464 (M+). Anal. Calcd for C28H24O3Fe: C, 72.43;
H, 5.21. Found: C, 72.53; H, 5.14.
Syn th esis of (R)-(η5-1-Hydr oxydiph en ylm eth yl-2-m eth -
yl-4-ph en ylcyclopen tadien yl)di(car bon yl)m eth ylir on ((R)-
8). To a solution of CpbFe(CO)2Me [(R)-7b] (0.741 g, 1.60 mmol)
in diethyl ether (50 mL) at -78 °C was added dropwise a
solution of 1.8 M phenyllithium (2.2 mL, 2.5 equiv) in 7:3
cyclohexane/diethyl ether. The reaction mixture was treated
as discribed for (S)-8, yielding 0.503 g (68%) of (R)-8 as orange-
yellow crystals and 0.151 g (20%) of unreacted CpbFe(CO)2Me.
IR (KBr, cm-1): 1996, 1934 (terminal CO). 1H NMR (400 MHz,
acetone-d6): δ -0.03 (3H, s, Fe-CH3), 1.89 (3H, s, Cp-CH3),
4.72 (1H, d, J ) 2.0 Hz, Cp), 5.28 (1H, d, J ) 2.0 Hz, Cp), 5.31
(1H, s, OH), 7.22-7.26 (1H, m, Ph), 7.30-7.39 (10H, m, Ph),
7.42-7.44 (2H, m, Ph), 7.47-7.50 (2H, m, Ph). 13C NMR (100
MHz, acetone-d6): δ -17.65 (Fe-CH3), 13.55 (Cp-CH3), 78.76
(COH), 87.45, 90.04, 94.97, 101.41, 110.43 (Cp), 126.33, 128.08,
128.10, 128.20, 128.28, 128.45, 128.45, 128.72, 129.44 (Ph),
133.70, 147.14, 147.26 (ipso-Ph), 218.36, 218.90 (terminal CO).
Mass (FAB): m/z 464 (M+). Anal. Calcd for C28H24O3Fe: C,
72.43; H, 5.21. Found: C, 72.40; H, 5.25.
Syn th esis of (R)-(η5-1-Hydr oxydiph en ylm eth yl-2-m eth -
yl-4-ph en ylcyclopen tadien yl)di(car bon yl)m eth ylsu lfon yl-
ir on ((R)-9). Sulfur dioxide was condensed into a flask
containing CpcFe(CO)2Me [(R)-8] (0.113 g, 0.243 mmol) at -78
°C. The red solution was treated as discribed for (S)-9, yielding
0.116 g (91%) of (R)-9 as a yellow powder. IR (KBr, cm-1):
2048, 2002 (terminal CO), 1179 (SO). 1H NMR (400 MHz,
acetone-d6): δ 1.94 (3H, s, Cp-CH3), 2.88 (3H, s, SO2CH3),
5.51 (1H, d, J ) 2.0 Hz, Cp), 5.91 (1H, d, J ) 2.0 Hz, Cp), 7.21
(1H, s, OH), 7.27-7.42 (9H, m, Ph), 7.47-7.49 (2H, m, Ph),
7.55-7.57 (2H, m, Ph), 7.67-7.69 (2H, m, Ph). 13C NMR (100
MHz, acetone-d6): δ 13.85 (Cp-CH3), 58.97 (SO2CH3), 77.81
(COH), 85.22, 88.02, 98.39, 109.89, 111.92 (Cp), 127.54, 127.97,
128.16, 128.16, 128.21, 128.69, 128.77, 129.92, 130.30 (Ph),
130.40, 147.11, 147.20 (ipso-Ph), 211.43, 212.14 (terminal CO).
Mass (FAB): m/z 529 (M+). Anal. Calcd for C28H24O5SFe: C,
63.65; H, 4.58; S, 6.07. Found: C, 63.96; H, 4.81; S, 5.94.
Da ta Collection . Complexes (S)-4a , (R)-4b, and (S)-8 were
recrystallized from diethyl ether/hexane. Cell constants were
determined on a Rigaku AFC5R four-circle automated diffrac-
tometer from setting angles of 25 reflections in the range 30.0°
< 2θ < 40.0°. The crystal parameters along with data collection
details are summarized in Table 4. Data collection was carried
out on a Rigaku AFC5R diffractometer. Intensities were
measured by the ω-2θ scan method using Mo KR radiation
(λ ) 0.71069). A scan rate for (S)-4a and (R)-4b of 8.0° min-1
was used, and for (S)-8, 16.0° min-1. Throughout the data
collection, the intensities of the three standard reflections were
measured every 150 reflections as a check of the stability of
the crystals, and no decay was observed.
A total of 4094 independent intensities were measured for
(S)-4a , 3025 for (R)-4b, and 3047 for (S)-8. Of these, there are,
respectively, 2245 (I > 3.00σ(I)), 2699 (I > 3.00σ(I)), and 1985
(I > 3.00σ(I)) unique reflections, which were used in the
solutions and refinements of the structures. Intensities were
corrected for Lorentz and polarization effects and for absorp-
tion.
Deter m in a tion of th e Str u ctu r es. The structures were
solved by heavy-metal Patterson methods (DIRDIF92 PATTY)
and expanded using Fourier techniques. Hydrogen atoms were
calculated at the ideal positions with the C-H distance of 0.95
Å. Hydrogen atoms were included but not refined. The final
refinement converged to R ) 0.043 and Rw ) 0.049 for (S)-4a ,
R ) 0.044 and Rw ) 0.047 for (R)-4b, and R ) 0.051 and Rw
0.063 for (S)-8, respectively. Final difference Fourier syntheses
showed peaks at heights up to 0.33-1.10 e Å-3
)
.
Ack n ow led gm en t. This work was partly supported
by a Grant-in-Aid for Scientific Research from the
Ministry of Education, Science, Sports and Culture of
J apan (No. 07454196). We thank the Material Analysis
Center of ISIR, Osaka University, for X-ray measure-
ments and elemental analyses.
Syn th esis of (S)-(η5-1-Hyd r oxyd ip h en ylm eth yl-2-m eth -
yl-4-ph en ylcyclopen tadien yl)di(car bon yl)m eth ylsu lfon yl-
ir on ((S)-9). Sulfur dioxide was condensed into a flask
containing CpcFe(CO)2Me [(S)-8] (0.105 g, 0.226 mmol) at -78
°C.19 The temperature was maintained at -78 °C, while the
red solution was stirred for 10 min. The reaction mixture was
gradually warmed to room temperature, and sulfur dioxide
was evaporated. The residue dissolved in dichloromethane (5
mL) was chromatographed on silica gel. After removing a small
amount of byproducts eluted with dichloromethane, a yellow
band eluting with a mixture of 1:1 dichloromethane/methanol
was collected. Product (S)-9 was isolated from the yellow band
Su p p or tin g In for m a tion Ava ila ble: Tables of X-ray
crystallographic data for complexes (S)-4a , (R)-4b, and (S)-8.
This material is available free of charge via the Internet at
http://pubs.acs.org.
OM9810347