Planar chiral Cp*Ru complexes. 2.1 Bis(allyl) and -(arene) complexes derived from (R)-carvone

Article abstract of DOI:10.1021/om960961f

Reaction of [Cp*RuOMe]₂ (1) with either enantiomer of the naturally occurring ketonic diterpene carvone or the trimethylsilyl enolate derived thereof leads to homochiral Cp*Ru-π-complexes 6-9, where the Cp*Ru moiety is bound to either the exocy

Full text of DOI:10.1021/om960961f

3950
Organometallics 1997, 16, 3950-3958
P la n a r Ch ir a l Cp *Ru Com p lexes. 2.1 Bis(a llyl) a n d
-(a r en e) Com p lexes Der ived fr om (R)-Ca r von e
Roland Pasch, Ulrich Koelle,* Beate Ganter, and Ulli Englert
Institute of Inorganic Chemistry, Technical University of Aachen, Professor-Pirlet-Strasse 1,
D-52074 Aachen, Germany
Received November 12, 1996X
Reaction of [Cp*RuOMe]2 (1) with either enantiomer of the naturally occurring ketonic
diterpene carvone or the trimethylsilyl enolate derived thereof leads to homochiral Cp*Ru-
π-complexes 6-9, where the Cp*Ru moiety is bound to either the exocyclic double bond or
an allyl function derived from it as well as to an enone or ene system in the ring. Full
aromatization of the cyclic enone under the same reaction conditions was achieved with
7,8-dihydrocarvone or its trimethylsilyl enolate, respectively, giving complexes 13 and 14.
The carvacrole complex 14 (and consequently also 13) is shown by the NMR spectra of the
diasteroisomers obtained through derivatization with (S)-camphorsulfonic acid to be
homochiral, thus, central chirality of the carvone has been fully transformed into planar
chirality of the carvacrole complex. Compounds 6, 7‚BF4, 7‚CF3SO3, 8‚CF3SO3, and 14‚CF3-
SO3 where characterized by single-crystal X-ray analysis, which allowed for the determination
of the absolute configuration of the latter.
In tr od u ction
High enantiomeric excesses in the course of π-com-
plexation had only been observed in cases where the
chiral center is part of an annelated ring close to the
unsaturated carbocycle giving rise to diastereotopic
faces. Thus, enantiomerically pure (oxohydronaphtha-
lene)Cr(CO)3 was obtained from enantiopure 5-hydroxo-
hydronaphthalene using naphthalene chromium tricar-
bonyl as a Cr(CO)3 transfer agent.8 Another possibility
to achieve enantioselective π-complexation was the use
of chiral intermediates or auxiliary ligands which are
lost in the complexation step but can still lead to the
differentiation of si/re faces.9
A still more rigorous approach is the transformation
of a chiral center in the course of the generation of an
element of planar chirality, as was exemplified in the
synthesis of planar chiral allyl-Fe(CO)4 complexes from
chiral allyl ethers.10 These reactions require the trans-
formation of an sp3 into an sp2 carbon atom whereby
the unsaturated carbon chain is extended.
Among the metal fragments that have shown par-
ticular versatility with respect to this kind of transfor-
mations at π-ligands is the Cp*Ru (Cp* ) η5-C5Me5)
fragment. It may be generated either by elimination
of methanol from the coordinatively unsaturated alkoxy
complex [Cp*RuOMe]211 (1) or in the form of the solvent-
stabilized cationic complexes [Cp*Ru(s)]+ (2) generated
by the action of a noncoordinating acid on 1.12 In
particular, cations 2 were shown to complex not only to
a wide variety of arenes and cyclotrienes but also to
effect dehydrogenation and dehydration of cyclic olefins,
such as cyclohexene, of enones, such as cyclohexenone,
Planar chiral transition metal complexes have in
recent times become increasingly important substrates
and targets in organic synthesis. This is due to the
highly stereospecific elaborations possible in π-ligand
systems complexed to transition metal fragments. Di-
astereospecific metalation of substituted ferrocenes2 and
arene tricarbonyl Cr complexes3 as well as carbon-
carbon bond forming reactions at cationic dienyl-Fe-
4
(CO)3 and arene tricarbonyl Cr5 complexes are inten-
sively studied examples. In cases where the π-ligand
is prochiral, planar chirality is generated in the com-
plexation reaction and any successive stereospecific
elaborations will lead to enantiomerically pure com-
pounds, only to the extent to which the enantiomeric
purity of the starting π-complex can be ascertained. A
straightforward strategy to obtain enantiomerically
pure or enriched planar chiral π-complexes exists in
diastereoselective complexation of π-ligands bearing at
least one chiral substituent, such as a menthylcarboxy
group,6 but so far this strategy has been met with
limited success with respect to the optical purity of the
products, and separation of the diastereoisomers was
generally necessary.7
X Abstract published in Advance ACS Abstracts, August 1, 1997.
(1) For part 1, see: Koelle, U.; Bu¨cken, K.; Englert, U. Organome-
tallics 1996, 15, 1376.
(2) (a) Marquarding, D.; Klusacek, H.; Gokel, G.; Hoffmann, P.; Ugi,
I. J . Am. Chem. Soc. 1970, 92, 5389. (b) Aratani, T.; Gonda, T.; Nozaki,
H. Tetrahedron Lett. 1969, 2265. (c) Riant, O.; Samuel, O.; Kagan, H.
B. J . Am. Chem. Soc. 1993, 115, 5835.
(3) (a) Ku¨ndig, E. P.; Liu, R.; Ripa, A. Helv. Chim. Acta 1992, 75,
2657. (b) Alexakis, A.; Kanger, T.; Mangeney, P.; Rose-Munch, F.;
Perrotey, A.; Rose, E. Tetrahedron: Asymmetry 1995, 6, 2135. (c) Ibid.
1995, 6, 47.
(4) (a) Knoelker, H. J .; Baum, G.; Kosub, M. Synlett 1994, 1012. (b)
Knoelker, H. J .; Bauermeister, M. Helv. Chim. Acta 1993, 76, 2500.
(5) Davies, S. G.; Donohoe, T. J . Synlett. 1993, 323.
(6) (a) Uno, M.; Ando, K.; Komatsuzaki, N.; Takahashi, S. J . Chem.
Soc., Chem. Commun. 1992, 964. (b) Uno, M.; Ando, K.; Komatsuzaki,
N.; Tanaka, T.; Sawada, M.; Takahashi, S. J . Chem. Soc., Chem.
Commun. 1993, 1549. (c) Pearson, A. J .; Chang, K.; McConville, D.
B.; Youngs, W. J . Organometallics 1994, 13, 4. (d) Schmalz, H.-G.;
Hessler, E.; Bats, J . W.; Du¨rner, G. Tetrahedron Lett. 1994, 35, 4543.
(e) Schmalz, H.-G.; Hessler, E.; Du¨rner, G. Tetrahedron Lett. 1994,
35, 4543. (f) Komatsuzaki, N.; Uno, M.; Shirai, K.; Tanaka, T.; Sawada,
M.; Takahashi, S. J . Organomet. Chem. 1995, 498, 53.
(7) Moriata, N.; Kurita, M.; Ito, S.; Asao, T.; Sotokawa, H.; Tajiri,
A. Tetrahedron: Asymmetry 1995, 6, 35.
(8) Schmalz, H.-G.; Millies, B.; Bats, J . W.; Du¨rner, G. Angew. Chem.
1992, 104, 640; Angew. Chem., Int. Ed. Engl. 1992, 31, 631.
(9) Kno¨lker, H. J .; Hermann, H. Angew. Chem. 1996, 108, 363.
(10) (a) Enders, D.; Finkham. M. Synlett. 1993, 401. (b) Enders, D.;
Finkham, M. Liebigs Ann. Chem. 1993, 551. (c) Enders, D.; J andeleit,
B.; Raabe, G. Angew. Chem. 1994, 106, 2033; Angew. Chem., Int. Ed.
Engl. 1994, 33, 1949.
(11) (a) Koelle, U.; Kossakowski, J . J . Chem. Soc., Chem. Commun.
1988, 549. (b) Loren, S. D.; Campion, B. K.; Heyn, R. H.; Don Tilley,
T.; Bursten, B. E.; Luth, K. W. J . Am. Chem. Soc. 1989, 111, 4712. (c)
Koelle, U.; Kossakowski, J . Inorg. Synth. 1992, 29, 225.
S0276-7333(96)00961-2 CCC: $14.00 © 1997 American Chemical Society

Planar Chiral Cp*Ru Complexes
Organometallics, Vol. 16, No. 18, 1997 3951
Sch em e 1. Rea ction of 1 a n d 2 w ith Cycloh exen on e
and, under more forcing conditions, even saturated
cyclic ketones and alcohols to give mostly Cp*Ru-
(benzene)+ derivatives.13 The reaction has been utilized
to afford aromatization of ring A in 3-keto steroids, such
as testosterone and progesterone, with expulsion of the
17-Me group (as methane) and even of the 1,4-dienonic
steroid prednisolone which was degraded under these
conditions to 2-methyl-5-hydroxybenzaldehyde com-
plexed to Cp*Ru.14 Similar reactions have been effected
with 2 and ketonic terpenes, in particular carvone (4)
or carvole ester which gave the corresponding arene
complexes with or without loss of the oxygen functional-
ity.15
We found that not only 2 but also the neutral methoxy
complex 1 aromatizes activated cyclic olefins to give the
corresponding oxocyclohexadienyl complexes, e.g., 3 in
Scheme 1, at ambient temperature. This observation
has led us to utilize 1 as well as 2 for stereospecific
transformations of carvone and dihydrocarvone. The
results, as detailed below, differ markedly from the ones
previously described with the same system.
Applying the reactions of Scheme 1 to the naturally
occurring diterpene carvone (4), which is readily avail-
able in either enantiomerically pure form, should in
principal offer the possibility for an enantioselective
complexation of the Cp*Ru moiety to the newly formed
arene. Preferential attack of the Cp*Ru fragment from
the rear side with respect to the isopropenyl group
should lead to planar chiral Cp*Ru complexes in high
enantiomeric purity.
Reactions conducted with (R)-carvone are shown in
Scheme 2. As sources of Cp*Ru, we used 1 or 2, the
latter being generated from 1 and acid in situ. The
cyclic enone was either 4 or the trimethylsilyl enolate
(5) derived from it.
The products formed in the reactions of Scheme 2,
however, were not arene complexes but were an allyl-
ene (6), bisallyl (7), or triene (diene-ene) complex (8).
Primary attack of the Cp*Ru moiety obviously is at the
isopropenyl double bond and not at the enone function-
ality. (Note, however, that cyclic monoenes do not react
under these mild conditions.) In 6 and 7, dehydroge-
nation has occurred at the isopropenyl group. This
finding is in accord with previous observations where
the reaction of 1 with propylene has led to allyl
complexes in high yield under similar conditions.16 6/7
as well as 8/9 form Brønsted acid/base pairs where
deprotonation of 7 and 8 is effected with triethylamine
in acetone. Although the formation of 6 as indicated in
Scheme 2 was clean by NMR, it proved difficult to
separate the product from excess carvone. Samples for
crystallization and analysis are therefore better ob-
tained via deprotonation of 7.
In order to facilitate aromatization in the course of
the complexation, carvone was converted into its trim-
ethylsilyl enolate (5). In this case, however, 2 simply
complexed to the preformed η6-system of double bonds
with no further dehydrogenation. Note, however, the
hydrogen shift from the 5-position in 5 to the 6-position
in 8. Hydrolysis of the silyl enol ether appears to be
quite facile in the cationic complex and may proceed
with methanol being formed with the generation of 2
from 1.
Resu lts a n d Discu ssion
Rea ction s of Ca r von e. As shown in Scheme 1,
complex 1 reacts with cyclohexenone to give Cp*Ru-
(oxocyclohexadienyl) (3). Aromatization, under these
conditions, requires at least one hydrogen in an allylic
position and does not allow quarternary carbon atoms
in the ring. Thus, no complexation was observed from
1 and 4,4-dimethylcyclohexenone. In the course of
dehydrogenation reactions performed with 2, elimina-
tion of hydroxy and even alkyl groups has been fre-
quently observed.13-15 In contrast, under the milder
conditions applied in the present experiments, those
functionalities at the cyclic precursors were preserved.
This is important in the present context since oxo,
hydroxy, and alkyl groups not only function as stereo-
chemical markers in introducing planar chirality of the
product complexes, but, moreover, give the possibility
of further elaborating the complexed arene in a ste-
reospecific manner (see below).
When using 2 as the source of Cp*Ru, care has to be
taken not to bring the carvone in contact with an acidic
medium since it undergoes a facile acid-catalyzed rear-
rangement to the respective phenol (carvacrole). Once
the arene is formed independent of the metal fragment,
this latter process will give the arene complex12,17 but
(12) (a) Koelle, U.; Wang, M. H. Organometallics 1990, 9, 195. (b)
Fagan, P. J .; Ward, M. D.; Caspar, J . V.; Calabrese, J . C.; Krusic, P. J .
J . Am. Chem. Soc. 1988, 110, 2981. (c) Fagan, P. J .; Ward, M. D.;
Calabrese, J . C. J . Am. Chem. Soc. 1989, 111, 1698. (d) Chaudret, B.;
He, X.; Huang, Y. J . Chem. Soc., Chem. Commun. 1989, 1844.
(13) Rondon, D.; Chaudret, B.; He, X.-D.; Labroue, D. J . Am. Chem.
Soc. 1991, 113, 5671.
(14) Urbanos, F.; Halcrow, M. A.; Fernandez-Baeza, J .; Dahan, F.;
Labroue, D.; Chaudret, B. J . Am. Chem. Soc. 1993, 115, 3483.
(15) Carreno, R.; Urbanos, F.; Dahan, F.; Chaudret, B. New. J .
Chem. 1994, 18, 449.
(16) Koelle, U.; Kang, B.-S.; Spaniol, T. P.; Englert, U. Organome-
tallics 1992, 11, 249.

3952 Organometallics, Vol. 16, No. 18, 1997
Sch em e 2. Rea ction s Con d u cted w ith Ca r von e
Pasch et al.
1
1
without any stereochemical preference. The result of
Chaudret et al.15 who had obtained [Cp*Ru(carvacrole)]-
CF3SO3 (14) from the same reaction essentially as a
racemic mixture is probably due to this sequence. Reac-
tions leading to 7 and 8 have, therefore, been conducted
in such a way as to mix 1 in a slight stoichiometric
excess with triflic acid to ensure complete consumption
of the latter prior to the addition of 4.
cases by use of two-dimensional H/13C COSY and H/
1H NOESY spectra. The latter, in particular, allowed
the location of the isopropenyl group in 9 to be assigned
as being directed toward CH2 in the oxocyclohexenyl
ring.
All of the complexes 6-9 are formed with 100%
stereospecifity. The ligand geometry in these cases
allows only one orientation with respect to the Cp*Ru
moiety and, thus, determines the configuration at Ru
as the newly formed chiral center. In addition, 6, 7, and
8 have been shown by X-ray structure analysis to be
pure enantiomers. Possible elaboration at the enone or
allylic function (such as addition of nucleophiles) is
therefore expected to generate new chiral centers with
high optical purity.
We verified that neither 6 nor 7 rearranged into 13
or 14 under the reaction conditions, i.e., at ambient
temperature. The bis(allyl) complex 7 rearranged cleanly
to 14 at 100 °C in CH2Cl2 over 50 h. Determination of
the specific rotation, however, showed the product to
25
be racemic ([R]546 ) 0). Heating 7 in toluene at 100
°C gave the toluene complex [Cp*Ru(tol)]+, together
with free carvone. This result suggests that rearrange-
ment requires decomplexation of carvone and recom-
plexation as carvacrol, formed by adventitious traces of
acid with the loss of stereochemical information. The
reaction of 1 with carvacrole is one way to obtain
racemic 13 (and 14) which is needed for comparison
(vide infra). This reaction was shown by NMR to
proceed via the bridged phenol complex [Cp*Ru(µ-OR)]2,
R ) 2-Me-5-isopropylphenol, which slowly converted to
13.18
Rea ction s of 7,8-Dih yd r oca r von e. Since we could
not transform any of the allylic or ene-diene structures
of 6-9 into arenes in a stereospecific way, a second set
of experiments was conducted where complexation at
the exocyclic double bond was blocked by hydrogenation
of carvone to 7,8-dihydrocarvone 10, which is easily
accomplished using a PtO2 catalyst. Results of reactions
using 10 or the silyl enol ether (11) derived thereof are
summarized in Scheme 3. Reaction with 2 under the
same conditions as performed with carvone now led to
aromatization of the ring, but even under those mild
conditions dehydration was favored over dehydrogena-
tion to give the achiral p-cymene complex 12. The
desired oxocyclohexadienyl complex 13 was only ob-
tained in the absence of acid with 1 as the source of
Cp*Ru, which reacted with either 10 or the the silyle-
nolate 11 (Scheme 3, entries 2 and 3).
Complexes 6-9 were identified by their 1H and 13C
NMR spectra, as given in the Experimental Section.
Ambiguities in the assignment of carbon atoms in the
ring as well as ring hydrogens could be resolved in all
(17) Koelle, U.; Wang, M. H.; Raabe, G. Organometallics 1991, 10,
2573.
(18) Bu¨cken, K.; Koelle, U.; Pasch, R.; Ganter, B. Organometallics
1996, 15, 3095.

Planar Chiral Cp*Ru Complexes
Organometallics, Vol. 16, No. 18, 1997 3953
Sch em e 3. Rea ction s Con d u cted w ith 7,8-Dih yd r oca r von e
Note that in the course of aromatization the chiral
center at C5 is lost and the oxocyclohexadienyl ligand
is now prochiral. However, since attack of the Cp*Ru
moiety is expected to principally be from the face
opposite to the isopropyl group, in the case of e.g. (R)-
dihydrocarvone it will appear on the si-side of the planar
aromatic cycle. Conversion of 13a into the phenol cation
14a by acid will not change the stereochemistry. In
addition 14b was prepared as a racemate by reacting
aromatic carvacrole, generated from 4 and triflic acid,
see above, with 2 (entry 4 in Scheme 3).
Molecu la r Str u ctu r es of 6, 7+, 8, a n d 14. The
molecular structures of the compounds 6, 7‚CF3SO3, 7‚-
BF4, 8, and 14 were elucidated by single-crystal X-ray
diffraction. Pertinent distances and angles are collected
in Table 1, where data have been arranged in the same
order for all independent molecules, thus enabling
comparison and allowing differences in the structures
to be easily noted.
In the neutral complex 6 (Figure 1), Ru is bound to
carbon atoms C2 and C3 of the ring and to three carbon
atoms C8-C10 of the isopropenyl group which adopts
an endo conformation with respect to the Cp*Ru moiety.
Distances to the allylic carbons are quite normal,
whereas one of the olefinic carbons is about 0.1 Å further
apart than in comparable ethylene complexes of the
Cp*Ru moiety.16,19 Likewise bond lengths and angles
within the carbon framework compare well with those
found for Ru ene-allyl systems. The bond angles at Ru
in 6 compare well with those in Cp*Ru(allyl)(propene).
The angles Colef-Ru-Ct-allyl are 87.7 and 78.3° in 6 and
are 85.6 and 90° in Cp*Ru(allyl)(propene).16 Thus, in
6 the ene and allyl parts are only slightly closer together
than in a complex where the same ligand types at
Cp*Ru are free to arrange in space.
In order to assess the optical purity of 13a /14a and
the racemic nature of 13b/14b, respectively, both forms
of 13 were converted into diastereomeric carvacrole
camphorsulfonates (15a /b) by esterification with homo-
chiral (S)-camphorsulfonyl chloride (Scheme 4). Thus,
15b derived from racemic 13b showed doubling of
1
signals in the H NMR, most easily seen in the doublet
of CH2 protons of the camphorsulfonyl residue close to
the SO3 group near 3.6 ppm. The same spectra of 15a ,
derived from 13a consisted of only one set of signals
(apart from some 14 which was formed in the esterifi-
cation procedure due to the presence of some camphor-
sulfonic acid) proving 100% enantiomeric purity of the
arene complexes within the limits of NMR detection.
As outlined in Scheme 4, the neutral complex 13 was
reacted with other electrophiles such as MeI, MeCOCl,
and Ph2PCl in a similar manner. This protocol is in
principal suited to generate enantiopure arene com-
plexes with a wide variety of functionalities. In some
of the products, however, the O-E bond has been found
to be sensitive to hydrolysis.
-
Complex 7 was measured as the CF3SO3 salt but
showed disorder in the anion. Subsequent structure
determination as the BF4- salt unfortunately revealed
four independent molecules in the unit cell. Both
salts crystallize in the space group P21 and show the
(19) Masuda, K.; Saitoh, M.; Aoki, K.; Itoh, K. J . Organomet. Chem.
1994, 473, 285.

3954 Organometallics, Vol. 16, No. 18, 1997
Sch em e 4. Der iva tiza tion of th e Ca r va cr ole Com p lex
Pasch et al.
Ta ble 1. Bon d Dista n ces a n d Bon d An gles of 6, 7, 8, a n d 14
7‚BF4
14‚CF3SO3
6
7‚CF3SO3
8‚CF3SO3
Bond Distances
Ru-C2
Ru-C3
Ru-C4
Ru-C5
Ru-C6
Ru-C7
Ru-C8
Ru-C9
Ru-C10
Ru-CCp*-plane
C2-C3
C3-C4
C4-C5
C5-C6
C6-C7
C2-C7
C5-C8
C8-C9
C8-C10
O1-C7
C1-C2
2.231(6)
2.133(6)
2.25(1)
2.25(1)
2.24(1)
2.18(1)
2.16(1)
2.23(1)
2.20(1)
2.29(1)
2.23(1)
2.22(1)
2.271(4)
2.173(4)
2.276(4)
2.23(1)
2.33(1)
2.16(2)
2.21(2)
2.21(2)
2.25(1)
2.25(1)
2.19(1)
2.21(2)
2.25(2)
2.26(2)
2.14(2)
2.49(1)
2.14(1)
2.16(2)
2.13(2)
1.907
1.43(2)
1.49(2)
1.53(2)
1.56(2)
1.49(2)
1.40(2)
1.46(2)
1.40(2)
1.44(2)
1.35(1)
1.49(2)
2.46(1)
2.15(1)
2.18(1)
2.21(1)
1.884
1.41(2)
1.52(2)
1.49(2)
1.52(2)
1.43(2)
1.35(2)
1.50(2)
1.33(2)
1.42(2)
1.33(2)
1.54(2)
2.31(1)
2.15(1)
2.21(2)
2.26(2)
1.888
1.40(2)
1.56(2)
1.56(2)
1.49(2)
1.55(2)
1.32(2)
1.49(2)
1.40(2)
1.38(2)
1.32(2)
1.57(2)
2.41(1)
2.14(1)
2.17(2)
2.21(1)
1.891
1.39(2)
1.47(2)
1.48(2)
1.53(2)
1.49(2)
1.39(2)
1.49(2)
1.39(2)
1.42(2)
1.39(2)
1.48(2)
2.42(1)
2.17(1)
2.17(2)
2.25(1)
1.897
1.41(2)
1.51(2)
1.52(2)
1.55(2)
1.45(2)
1.42(2)
1.53(2)
1.39(2)
1.40(2)
1.35(2)
1.49(2)
2.534
2.320(4)
2.250(4)
2.130(5)
2.189(6)
2.199(6)
1.896
1.432(8)
1.517(8)
1.522(8)
1.499(9)
1.51(1)
1.855
1.810(1)
1.37(2)
1.52(2)
1.46(2)
1.42(2)
1.42(2)
1.44(2)
1.55(2)
1.56(2)
1.45(2)
1.37(1)
1.53(2)
1.798(1)
1.35(2)
1.40(2)
1.42(2)
1.38(2)
1.32(2)
1.43(2)
1.50(2)
1.42(3)
1.59(2)
1.47(1)
1.54(2)
1.434(6)
1.390(6)
1.495(6)
1.518(6)
1.505(6)
1.386(5)
1.505(6)
1.389(6)
1.507(6)
1.354(5)
1.498(5)
1.48(1)
1.509(9)
1.403(9)
1.456(8)
1.245(8)
1.51(1)
Bond Angles
C2-C3-C4
C3-C4-C5
C4-C5-C6
C5-C6-C7
C6-C7-C2
C7-C2-C3
C4-C5-C8
C6-C5-C8
C9-C8-C10
C5-C8-C9
C5-C8-C10
C2-C7-O1
C6-C7-O1
C1-C2-C3
C1-C2-C7
118.6(6)
105.8(5)
108.1(6)
112.9(6)
118.2(6)
119.3(7)
107.0(5)
111.5(6)
114.6(6)
119.9(7)
124.4(7)
121.9(7)
119.8(7)
120.7(7)
113.3(5)
117(1)
111(1)
106(1)
111(1)
121(1)
117(1)
108(1)
106(1)
108(2)
123(2)
125(2)
117(1)
117(1)
121(1)
121(1)
116(1)
108(1)
108(1)
109(1)
123(1)
116(1)
109(1)
108(1)
115(1)
117(1)
124(1)
113(1)
119(1)
121(1)
123(1)
114(1)
107(1)
107(1)
109(1)
117(1)
123(1)
108(1)
110(1)
116(1)
124(1)
118(1)
120(1)
115(1)
115(1)
122(1)
122(1)
118(1)
109(1)
108(1)
107(1)
124(1)
114(1)
108(1)
109(1)
116(1)
119(1)
120(1)
113(1)
116(1)
124(1)
122(1)
120.4(4)
123.8(4)
110.5(4)
110.4(3)
120.4(4)
115.4(4)
96.8(3)
111.1(4)
121.1(4)
117.0(4)
121.3(4)
124.5(4)
112.0(4)
121.3(4)
122.6(4)
113(1)
123(1)
118(1)
119(1)
121(1)
124(1)
120(1)
122(1)
114(1)
107.9(9)
115(1)
116(1)
122(1)
118(1)
118(1)
121(1)
122(1)
118(1)
116(1)
130(1)
113(1)
116(1)
126(1)
105(1)
115(1)
110(1)
110(1)
120(1)
125(1)
122(1)
110(1)
108(1)
107(1)
126(1)
112(1)
109(1)
107(1)
114(1)
120(1)
123(1)
115(1)
115(1)
124(1)
121(1)
same enantiomer. Ru is bound to two allylic systems,
one made up of C3-C2-C7 and the other of C9-
C8-C10 in endo- and exo-conformations, respectively
(Figure 2). This endo- and exo-conformation has been
observed in other cationic CpRu and LRu (bis(allyl))
complexes as well,20 with Ru-Callyl distances in the

Planar Chiral Cp*Ru Complexes
Organometallics, Vol. 16, No. 18, 1997 3955
F igu r e 1. PLATON28 representation of 6, showing atom
numbering scheme and 30% probability ellipsoids. For bond
distances and angles, see Table 1.
F igu r e 3. PLATON representation of the cation of 8‚CF3-
SO3, showing atom numbering scheme and 30% probability
ellipsoids. For bond distances and angles, see Table 1.
F igu r e 2. PLATON representation of the cation of 7‚CF3-
SO3, showing atom numbering scheme and 30% probability
ellipsoids. For bond distances and angles, see Table 1.
F igu r e 4. PLATON representation of the cation of 14‚-
CF3SO3, showing atom numbering scheme and 30% prob-
ability ellipsoids. For bond distances and angles, see Table
1.
same range. The shortest distances are encoutered
for the bonds between Ru and the central carbon
atoms of both allyl moieties, C2 and C8, see Table 1.
Note the slightly shorter distance Ru-C10, disposed
roughly trans to C7, as compared to Ru-C9 and also
the very long distance Ru-C7 at the border of the
normal range for Ru-carbon bonds. The six-membered
ring adopts a skewed boat conformation with the
isopropenyl group in an axial position. As can be seen
from the C-C-C bond angles in Table 1, the Cp*Ru
unit in the bis(allyl) complex is bound to a strainless
carbon skeleton, which may explain the ready formation
of this system under the mild reaction conditions
employed.
Cation complex 8 was also crystallized as the triflate
salt. The Cp*Ru unit is complexed to the olefinic double
bond of the isopropenyl group and to a diene system of
the ring, i.e., the starting enol ether acts together with
the isopropenyl group as an η6-ligand (Figure 3). The
diene system is characterized by two short (1.390(6) and
1.386(5) Å) and one long (1.434(6) Å) carbon-carbon
bond. The distance Ru-C7 (2.534 Å) is outside the
normal range for Ru-C bonding, but the bond is
indispensable to be in keeping with the required elec-
tron count. Also in this molecule bond angles in the
dienol ligand are close to those in an unstrained carbon
skeleton.
The geometry of the two independent cation molecules
in the unit cell of homochiral 14a , crystallized as the
triflate salt, conform largely to the shape found in many
known Cp*Ru(arene)+ cations (Figure 4).12 The phe-
nolic hydroxyl group is hydrogen bonded to a sulfonate
oxygen of the anion. The distances of the isotropically
refined OH proton to OSO2 are 1.824(9) and 1.60(1) Å.
The Ru-Cp*plane distance in this complex is distinctly
less than in the allyl and dienyl complexes 6-8, an
observation which underlines the stronger back-bonding
capabilities21 of the allyl and ene-diene ligands in the
latter as compared to an arene. The absolute configu-
ration could be assigned reliably by refinement of
Flack’s enantiomorph polarity parameter22 (see Experi-
mental Section) and is the one expected from attack of
the Cp*Ru unit at the face opposite to the isopropyl
group. Note that stereoselectivity in this case is much
larger than the diastereoselectivity observed when
complexing Cp*Ru to the aromatic A ring of estrogenic
steroids.14,23
(20) (a) Itoh, K.; Masuda, K.; Fukahori, T.; Nakano, K.; Aoki, K.;
Hideo, N. Organometallics 1994, 13, 1020. (b) Wache, S.; Herrmann,
W. A.; Artus, G.; Nuyken, O.; Wolf, D. J . Organomet. Chem. 1995, 491,
181.
(21) Wang, M. H.; Englert, U.; Koelle, U. J . Organomet. Chem. 1993,
453, 127.
(22) Flack, H. D. Acta Crystallogr. 1983, A39, 876.

3956 Organometallics, Vol. 16, No. 18, 1997
Pasch et al.
(3R)-(+)-3-Isop r op yl-6-m et h yl-1-(t r im et h ylsiloxy)cy-
cloh exa -1,5-d ien e (11). Procedure used was similar to that
described above. Yield: 90%. [R]546 ) +109 (hexane, c )
Con clu sion
25
It was shown that aromatization of dihydrocarvone
by a Cp*Ru fragment under the appropriate reaction
conditions can proceed with complete transformation of
the central chirality of the starting terpene into planar
chirality of the resulting π-arene complex. Since the
dehydrogenative complexation has been observed, apart
1.31 × 10-2 g‚cm-3). 1H NMR (300 MHz, CDCl3): 0.18 (s, 9H,
SiMe3), 0.86 (d, J ) 6.7 Hz, 3H, i-Pr), 0.87 (d, J ) 6.7 Hz, 3H,
i-Pr), 1.59 (septbr, J ) 6.7 Hz, 1H, HC(CH3)2), 1.66 (ddd, J )
1.7, 1.7, 1.7 Hz, 3H, Me), 1.83-2.20 (alophatic protons, 3H,
CH2, HCCH(CH3)2), 4.78 (dbr, J ) 3.7 Hz, 1H, HCdCOSiMe3),
5.53 (m, 1H, HCdCMe). 13C NMR (75.4 MHz, CDCl3): 0.2
(SiMe3), 17.3 (Me), 19.8, 19.9 (i-Pr), 26.3 (CH2), 31.6 (HC(CH3)2),
40.3 (HCCH(CH3)2), 106.2 (HCdCOSiMe3), 123.6 (HCdCMe),
131.9, 149.5 (CMe, COSiMe3).
from the Cp*Ru fragment, with other Ru(II) moieties
2+ 24
also, e.g., Ru(H2O)6
,
the reaction may, under ap-
propriate conditions, provide a route not only to chiral
sandwich but also to chiral arene Ru half-sandwich
complexes.
(5R,1R)-[(1-Hyd r oxy-η3-5-isop r op en yl-2-m et h yl-η3-cy-
c loh e x-1-e n -3-yl)(η5-p e n t a m e t h ylc yc lop e n t a d ie n yl)-
r u th en iu m ] Tr iflu or om eth a n esu lfon a te ((R)-7‚CF 3SO3).
To 250 mg (0.43 mmol) of [Cp*RuOMe]2 in 10 mL of acetone
was added 0.8 mmol (70 µL) of CF3SO3H. The solution was
cooled to -78 °C, and 0.86 mmol (0.135 mL) of (R)-(-)-carvone
was added. After the mixture had reached room temperature,
hexane was slowly added to precipitate the product. The
brownish precipitate was repeatedly redissolved in acetone and
precipitated by addition of hexane to finally yield 0.322 g (70%)
of a yellow powder. Fp: 165 °C. [R]54625 ) -352 (acetone, c )
9.85 × 10-3 g‚cm-3). 1H NMR (500 MHz, CD2Cl2): 1.73 (s,
Cp*, 15H), 1.83 (s, H1, 3H), 3.21 (ddd, H3, J ) 4.0, 1.2, 1.2
Hz, 1H), 1.37 (dbr, H4, J ) 14.4 Hz, 1H), 1.73 (dm, H4′, J )
14.4 Hz, 1H), 2.56 (m, H5, 1H), 1.73 (d, H6, J ) 16.0 Hz, 1H),
2.32 (ddd, H6′, J ) 16.0, 4.0, 1.5 Hz, 1H), 1.59 (s, H9anti, 1H),
3.28 (d, H9syn, J ) 3.4 Hz, 1H), 2.01 (sbr, H10anti, 1H), 3.57
(dbr, H10syn, J ) 3 Hz, 1H). 13C NMR (125.6 MHz, CD2Cl2):
9.9, 101.7 (Cp*), 16.1 (C1), 80.0 (C2), 55.9 (C3), 33.3 (C4), 32.6
(C5), 28.8 (C6), 140.8 (C7), 110.5 (C8), 59.9 (C9), 58.3 (C10),
120.9 (q, CF3SO3-, J CF ) 320 Hz). IR (KBr, ν, cm-1): 3158
(m), 3003 (m), 2907 (m), 1554 (w), 1470 (m), 1444 (m), 1386
(m), 1352 (m), 1296 (s), 1236 (s), 1222 (s), 1157 (s), 1028 (s),
638 (s). MS (FAB): m/z (Irel) +VE 387 (100, M+ - CF3SO3-),
371 (7, M+ - CH4 - CF3SO3-), 357 (2, M+ - C2H5 - CF3SO3-),
343 (1, M+ - i-Pr - CF3SO3-), 233 (3, (Cp*Ru)+ - 4H); -VE
149 (100, CF3SO3-). Anal. Calcd for C21H29F3O4RuS: C, 47.10;
H, 5.46. Found: C, 47.08; H, 5.63.
Exp er im en ta l Section
Experiments were conducted under nitrogen with anhy-
drous, nitrogen-saturated solvents. The NMR spectra were
recorded on Bruker WH 250 and Varian Unitiy 300 and 500
instruments. Chiroptical data were obtained with a Perkin-
Elmer 241 polarimeter and a J asco J -41c spectrophotometer
(CD). Elemental analyses were performed by the microana-
lytical laboratory of the institute.
(5R)-(-)-5-Isop r op yl-2-m eth ylcycloh ex-2-en -1-on e ((R)-
(-)-d ih yd r oca r von e)25 (10). (R)-(-)-Carvone (33.3 g, 0.22
mol) in 50 mL of ethanol was hydrated at ambient temperature
with 0.22 mol of hydrogen over a PtO2 catalyst to form (R)-
(-)-dihydrocarvone. After consumption of the calculated
amount of hydrogen, the solution was filtered from the catalyst
25
and the product distilled in vacuo. Yield: 32 g (95%). [R]546
) -49 (hexane, c ) 1.51 × 10-2 g‚cm-3). 1H NMR (500 MHz,
CDCl3): 0.872 (d, J ) 6.7 Hz, 3H, i-Pr), 0.876 (d, J ) 6.7 Hz,
3H, i-Pr), 1.53 (sept, J ) 6.7 Hz, 1H, HC(CH3)2), 1.73 (ddd, J
) 2.5, 1.3, 1.3 Hz, 3H, Me), 1.80-2.45 (aliphatic protons, 5H,
CH2, CH2, HCCH(CH3)2), 6.70 (m, 1H, HCdCMe). 13C NMR
(125.6 MHz, CDCl3): 15.6 (Me), 19.4, 19.5 (i-Pr), 29.8, 42.0
(CH2, CH2), 31.9, 41.9 (HCCH(CH3)2), 135.3 (HCdCMe), 145.3
(HCdCMe), 200.7 (CdO).
(5R,1R)-[(1-Hyd r oxy-η3-5-isop r op en yl-2-m et h yl-η3-cy-
c loh e x-1-e n -3-yl)(η5-p e n t a m e t h ylc yc lop e n t a d ie n yl)-
r u th en iu m ] Tetr a flu or obor a te ((R)-7‚BF 4). The same
procedure as given above using HBF4 instead of CF3SO3H.
(3R)-(+)-3-Isop r op en yl-6-m eth yl-1-(tr im eth ylsiloxy)cy-
cloh exa -1,5-d ien e26 (5). To 5 mL (35.7 mmol) of diisopropy-
lamine in 20 mL of Et2O was added 35.7 mmol (14.3 mL of a
2.5 M solution of BuLi in hexane) of BuLi at -78 °C. After
being warmed to ambient temperature, the solution was
recooled to -78 °C and 5.5 mL (35.7 mmol) of (R)-(-)-carvone
was added dropwise. At ambient temperature, 4.6 mL (35.7
mmol) of trimethylsilyl chloride was added. Following evapo-
ration of the ether, the remaining silyl enol ether was dissolved
in hexane, the solution was filtered over Celite to remove LiCl,
the solvent was removed, and the product was distilled at 10-2
(5S,1S)-[(1-H yd r oxy-η3-5-isop r op en yl-2-m et h yl-η3-cy-
c loh e x-1-e n -3-yl)(η5-p e n t a m e t h ylc yc lop e n t a d ie n yl)-
r u th en iu m ] Tr iflu or om eth a n esu lfon a te ((S)-7‚BF 4). Pre-
pared in the same manner as the (R)-enantiomer using (S)-
25
carvone. [R]546 ) +329 (acetone, c ) 4.4 × 10-3 g‚cm-3).
(5R,2R)-(η3-5-Isop r op en yl-2-m eth yl-η2-cycloh ex-2-en -1-
on e)(η5-p en ta m eth ylcyclop en ta d ien yl)r u th en iu m (II) (6).
To 200 mg (0.37 mmol) of 7‚CF3SO3 in 10 mL of acetone was
added 55 µL (0.39 mmol) of triethylamine. The solvent was
removed in vacuo, and the oily residue was extracted with
hexane. Cooling the yellow hexane solution to -25 °C yielded
0.130 g (90%) of (5R,RRu)-(η3-5-isopropenyl-2-methyl-η2-cyclo-
hex-2-ene-1-one)(η5-pentamethylcyclopentadienyl)ruthenium-
25
Torr. Yield (90%). [R]546 ) +81 (hexane, c ) 7.55 × 10-3
g‚cm-3). 1H NMR (500 MHz, CDCl3): 0.19 (s, 9H, SiMe3), 1.68
(ddd, J ) 1.9, 1.9, 1.9 Hz, 3H, MeCdCH), 1.71 (dd, J ) 1.0,
1.0 Hz, 3H, MeCdCH2), 2.08 (dddq, J ) 16.5, 12.5, 4.0, 2.1
Hz, 1H, -CH2), 2.16 (dddq, J ) 16.8, 8.5, 4.9, 1.8 Hz, 1H,
-CH2), 2.99 (dq, J ) 2.1, 1.4 Hz, 1H, dCH2), 4.76 (m, 2H,
dCH2, HCdCOSiMe3), 5.54 (m, 1H, HCdCMe). 13C NMR
(125.6 MHz, CDCl3): 0.1 (SiMe3), 17.3 (MeCdCH), 20.5
(MeCdCH2), 28.6 (CH2), 41.8 (HCCH(CH3)dCH2), 105.8
(HCdCOSiMe3), 110.0 (dCH2), 123.1 (HCCMe), 131.9, 148.6,
149.8 (CdCH2, HCCMe, COSiMe3).
25
(II) as yellow crystals. Fp: 162 °C. [R]546 ) -13 (acetone, c
) 1.48 × 10-2 g‚cm-3). 1H NMR (500 MHz, acetone-d6): 1.68
(s, Cp*, 15H), 1.20 (s, H1, 3H), 2.29 (ddd, H3, J ) 3.3, 1.1, 1.1
Hz, 1H), 1.80 (dbr, H4, J ) 13.2 Hz, 1H), 2.01 (dd, H4′, J )
13.2, 4.6 Hz, 1H), 2.59 (dddbr, H5, J ) 4.6, 2.1, 1 Hz, 1H), 1.43
(ddd, H6, J ) 17.5, 3.3, 1 Hz, 1H), 1.65 (ddd, H6′, J ) 17.5,
3.1, 2.1 Hz, 1H), 0.77 (s, H9anti, 1H), 2.65 (d, H9syn, J ) 3 Hz,
1H), 1.06 (s, H10anti, 1H), 2.35 (d, H10syn, J ) 3 Hz, 1H). 13C
NMR (125.6 MHz, acetone-d6): 10.4, 96.6 (Cp*), 21.7 (C1), 56.8
(C2), 56.5 (C3), 34.0 (C4), 32.3 (C5), 41.4 (C6), 203.3 (C7), 106.1
(C8), 47.8 (C9), 46.7 (C10). IR (KBr, ν, cm-1): 2850 (m), 1627
(s), 1377 (m), 1362 (m), 1327 (m), 1305 (m), 1029 (m). MS (70
eV, EI): m/z (Irel) 385 (100, M+ - H), 371 (89, M+ - CH3), 358
(23) Vichard, D.; Gruselle, M.; El Amouri, H.; J aouen, G.; Vaisser-
mann, J . Organometallics 1992, 11, 976.
(24) Koelle, U.; Weissscha¨del, Chr.; Englert, U. J . Organomet. Chem.
1995, 490, 101.
(25) Beilstein, Handb. d. Org. Chemie, E III, Vol. VII/1, p 561, Syst.
No. 620.
(26) (a) Barner, B. A.; Liu, Y.; Rahman, M. A. Tetrahedron 1989,
45, 6101. (b) Girard, C.; Conia, J . M. Tetrahedron Lett. 1974, 3327. (c)
Lee, R. A.; McAndrews, C.; Patel, K. M.; Reusch, W. Tetrahedron Lett.
1973, 965. (d) House, H. O.; Czuba, L. J .; Gall, M.; Olmstead, H. D. J .
Org. Chem. 1969, 34, 2324.
(22, M+ - C2H4), 343 (37, M+ - i-Pr), 232 (24, (Cp*Ru)+
-
5H). Anal. Calcd for [C20H28ORu]: C, 62.31; H, 7.32.
Found: C, 61.96; H, 7.40.

Planar Chiral Cp*Ru Complexes
Organometallics, Vol. 16, No. 18, 1997 3957
(5S,1R)-[(1-H yd r oxy-η2-5-isop r op en e-2-m et h yl-η4-cy-
cloh exa -1,3-d ien e)(η5-p en t a m et h ylcyclop en t a d ien yl)-
r u th en iu m (II)] Tr iflu or om eth a n esu lfon a te (8‚CF 3SO3).
Prepared analogous to 7 from 250 mg (0.43 mmol) of 1, 0.8
mmol (70 µL) of CF3SO3H, and 0.86 mmol (0.190 mL) of 5.
Yield: 0.322 g (70%). Fp: 145 °C dec. [R]54625 ) -349 (acetone,
c ) 8.65 × 10-3 g‚cm-3). 1H NMR (500 MHz, CD2Cl2): 1.72
(s, Cp*, 15H), 1.99 (d, H1, J ) 0.5 Hz, 3H), 4.57 (d, H3, J )
6.6 Hz, 1H), 2.44 (ddd, H4, J ) 6.5, 5.3, 1.2 Hz, 1H), 3.34 (ddd,
H5, J ) 5, 5, 1.5 Hz, 1H), 1.24 (ddd, H6, J ) 15.4, 4.9, 0.7 Hz,
1H), 1.31 (ddd, H6′, J ) 15.5, 1.4, 1.4 Hz, 1H), 2.03 (s, H10,
3H), 2.75 (d, H9syn, J ) 1 Hz, 1H), 3.19 (d, H9anti, J ) 1.5 Hz,
1H). 13C NMR (125.6 MHz, CD2Cl2): 10.2, 93.7 (Cp*), 14.4
(C1), 76.4 (C2), 77.8 (C3), 33.9 (C4), 34.3 (C5), 23.3 (C6), 145.9
(C7), 60.3 (C8), 23.2 (C10), 49.3 (C9), 120.9 (q, CF3SO3-, J CF
) 320 Hz). IR (KBr, ν, cm-1): 3275 (m), 2917 (m), 1551 (s),
1484 (m), 1385 (m), 1289 (s), 1258 (s), 1227 (s), 1206 (s), 1157
CDCl3): 1.82 (s, Cp*, 15H), 5.30 (d, H3, J ) 5.8 Hz, 1H), 5.13
(dbr, H4, J ) 5.8 Hz, 1H), 6.14 (sbr, H6, 1H), 1.99 (s, H1, 3H),
2.50 (sept, H8, J ) 7.0 Hz, 1H), 1.19 (d, H9, H10, J ) 7.0 Hz,
3H), 1.26 (d, J ) 7.0 Hz, 3H), 9.36 (sbr, OH, 1H). 13C NMR
(125.6 MHz, CDCl3): 9.9, 93.7 (Cp*), 13.2 (C1), 110.1 (C2), 86.7,
81.0, 75.7 (C3, C4, C6), 88.8 (C5), 129.6 (C7), 30.8 (C8), 22.5,
22.8 (C9, C10), 120.9 (q, CF3SO3-, J CF ) 320 Hz). IR (KBr, ν,
cm-1): 3096 (m), 2973 (w), 2920 (w), 1536 (w), 1476 (m), 1453
(w), 1406 (m), 1387 (m), 1327 (m), 1298 (s), 1237 (s), 1221 (s),
1165 (s), 1030 (s), 638 (s). MS (FAB): m/z (Irel) +VE 387 (100,
M+ - CF3SO3-), 371 (8, M+ - CH4 - CF3SO3-), 357 (2, M+
-
C2H5 - CF3SO3-), 343 (1, M+ - i-Pr - CF3SO3-), 233 (3,
(Cp*Ru)+ - 4H); -VE 149 (100, CF3SO3-). Anal. Calcd for
[C21H29F3O4RuS]: C, 47.10; H, 5.46. Found: C, 46.53; H, 5.45.
(1 S )-[(η6 -1 -(S )-C a m p h o r s u l fo n y l -5 -i s o p r o p y l -2 -
m et h yl p h en ola t e)(η5-p en t a m et h ylcyclop en t a d ien yl)-
r u th en iu m (II)] Ch lor id e (15a ‚Cl). When an ether solution
of 0.043 g (0.17 mmol) of (1S)-(+)-camphor-10-sulfonyl chloride
was added to 0.066 g (0.17 mmol) of 13a dissolved in ether,
the product separated as a white solid, which was washed two
times with ether and dried. Yield: 0.104 g (96%). 1H NMR
(500 MHz, CDCl3): 1.88 (s, Cp*, 15H), 6.59 (dbr, H3, J ) 5.8
Hz, 1H), 6.06 (dbr, H4, J ) 5.8 Hz, 1H), 6.18 (sbr, H6, 1H), 2.24
(s, H1, 3H), 2.68 (sept, H8, J ) 6.9 Hz, 1H), 1.228 (d, H9, H10,
J ) 6.9 Hz, 3H), 1.230 (d, J ) 6.9 Hz, 3H), 3.80 (d, H11, H11′,
J ) 14.9 Hz, 1H), 3.36 (d, J ) 14.9 Hz, 1H), 1.88 (m, H14,
H14′, 1H), 2.37 (ddd, J ) 18.6, 4.0, 4.0 Hz, 1H), 2.12 (dd, H15,
J ) 4.4, 4.4 Hz, 1H), 1.42 (ddd, H16, H16′, J ) 13.0, 9.4, 4.0
Hz, 1H), 2.03 (m, 1H), 1.70 (m, H17, H17′, 1H), 2.29 (ddd, J )
15.0, 12.0, 4.0 Hz, 1H), 0.89 (s, H19, H20, 3H), 1.07 (s, 3H).
13C NMR (125.6 MHz, CDCl3): 10.2, 96.1 (Cp*), 13.9 (C1),
110.6 (C2), 86.5 (C3), 89.5 (C4), 95.2 (C5), 80.5 (C6), 119.4 (C7),
30.3 (C8), 22.4, 22.9 (C9, C10), 50.0 (C11), 58.2 (C12), 213.4
(C13), 42.4 (C14), 42.8 (C15), 26.7 (C16), 25.7 (C17), 48.2 (C18),
19.4, 19.6 (C19, C20).
(s), 1099 (m), 1033 (s), 978 (m), 637 (s). MS (FAB): m/z (Irel
)
+VE 387 (100, M+ - CF3SO3-), 385 (75, M+ - H2 - CF3SO3-),
371 (6, M+ - CH4 - CF3SO3-), 233 (3, (Cp*Ru)+ - 4H); -VE
149 (100, CF3SO3-). Anal. Calcd for [C21H29F3O4RuS]: C,
47.10; H, 5.46. Found: C, 47.19; H, 5.55.
(5S,2S)-(η2-5-Isop r op en -2-m et h yl-η3-cycloh ex-2-en -1-
on e-4-yl)(η5-p en t a m et h ylcyclop en t a d ien yl)r u t h en iu m -
(II) (9). Prepared by deprotonation of 8 (200 mg, 0.37 mmol)
with Et3N in acetone. Yield after extraction into hexane was
0.130 g (90%) as orange crystals. Fp: 163 °C. [R]54625 ) +146
(acetone, c ) 5.95 × 10-3 g‚cm-3). 1H NMR (500 MHz, CD2-
Cl2): 1.66 (s, Cp*, 15H), 1.41 (s, H1, 3H), 3.89 (d, H3, J ) 5.8
Hz, 1H), 2.65 (ddd, H4, J ) 6.7, 5.8, 1.2 Hz, 1H), 3.05 (ddd,
H5, J ) 6.5, 5.5, 2.1 Hz, 1H), 0.97 (ddd, H6, J ) 16.2, 2.1, 1.2
Hz, 1H), 1.07 (dd, H6′, J ) 16.2, 5.5 Hz, 1H), 1.88 (s, H9, 3H),
1.47 (d, H10syn, J ) 1.2 Hz, 1H, Hg), 2.05 (d, H10anti, J ) 1.2
Hz, 1H, Hg′). 13C NMR (125.6 MHz, CD2Cl2): 10.4, 90.3 (Cp*),
18.3 (C1), 43.9 (C2), 82.9 (C3), 24.9 (C4), 34.6 (C5), 34.8 (C6),
201.8 (C7), 58.5 (C8), 27.3 (C9), 43.7 (C10). IR (KBr, ν, cm-1):
2947 (w), 2888 (m), 1625 (s), 1377 (m), 1349 (m), 1311 (m),
(1R ,1S )-[(η6 -(S )-C a m p h o r s u lfo n y l-5-i s o p r o p y l-2-
m et h yl p h en ola t e)(η5-p en t a m et h ylcyclop en t a d ien yl)-
r u th en iu m (II)] Tr iflu or om eth a n esu lfon a te (15b). To 0.2
g (0.34 mmol) of [Cp*RuOMe]2 in 5 mL of acetone was added
60 µL (0.69 mmol) of CF3SO3H and subsequently 107 mL (0.69
mmol) of 5-isopropyl-2-methylphenol (carvacrol). The resulting
phenol complex was precipitated by addition of 50 mL of ether,
redissolved in acetone, and precipitated to give 0.18 g (50%)
as the triflate salt. After drying under high vacuum, the
complex was treated in ether with an equimolar amount of
n-BuLi to generate the neutral oxocyclohexadienyl complex
13b. To the mixture containing 13, LiCl, and CF3SO3Li in
ether was added an equimolar amount of (S)-(+)-camphor-10-
sulfonyl chloride. The resulting solid was separated, washed
with ether, and dried under high vacuum. It was freed from
1021 (m), 704 (w). MS (70 eV, EI): m/z (Irel) 385 (100, M+
H), 371 (78, M+ - CH3), 357 (24, M+ - C2H5), 343 (48, M+
-
-
i-Pr), 232 (28, (Cp*Ru)+ - 5H). Anal. Calcd for [C20H28ORu]:
C, 62.31; H, 7.32. Found: C, 62.24; H, 7.57.
(5R)-(η5-5-Isop r op yl-2-m eth yl-1-oxocycloh exa d ien yl)-
(η5-p en ta m eth ylcyclop en ta d ien yl)r u th en iu m (II) (13). (a)
To 0.37 g (1.27 mmol) of [Cp*RuOMe]2 dissolved in 10 mL of
benzene was added 0.4 mL (2.54 mmol) of (R)-(-)-dihydrocar-
vone. After 4 days at 30 °C, the solvent was removed in vacuo
and excess dihydrocarvone was extracted with hexane. The
residual orange brown solid was dissolved in Et2O, and the
solution was filtered over Celite. On concentration of the
solution, 0.23 g (47%) of product precipitated as a colorless
25
-
solid. Fp: 177 °C. [R]546 ) +1.6 (acetone, c ) 5.0 × 10-3
LiCl by dissolving in CHCl3, where only the CF3SO3 salt is
g‚cm-3). 1H NMR (500 MHz, CDCl3): 1.74 (s, Cp*, 15H), 1.77
(sbr, H1, 3H), 5.00 (d, H3, J ) 5.5 Hz, 1H), 4.72 (dd, H4, J )
5.5, 1.0 Hz, 1H), 4.87 (sbr, H6, 1H), 2.25 (sept, H8, J ) 6.9 Hz,
1H), 1.12 (d, H9, H10, J ) 6.9 Hz, 3H), 1.12 (d, J ) 6.9 Hz,
3H). 13C NMR (125.6 MHz, CDCl3): 10.1, 89.6 (Cp*), 14.8 (C1),
109.6 (C2), 87.1, 76.6, 75.4 (C3, C4, C6), 87.5 (C5), 149.1 (C7),
31.0 (C8), 22.3, 23.2 (C9, C10). IR (KBr, ν, cm-1): 3034 (w),
2955 (m), 2904 (m), 1555 (s), 1500 (m), 1477 (m), 1379 (m),
soluble, filtering off the solid, and evaporating the solvent. 1H
NMR (500 MHz, CDCl3): 1.86, 1.87 (s, Cp*, 15H), 6.05, 6.07
(dbr, H3, J ) 6.1 Hz, 1H), 5.83, 5.85 (dbr, H4, J ) 6.0 Hz, 1H),
6.16, 6.16 (sbr, H6, 1H), 2.20, 2.22 (s, H1, 3H), 2.675, 2.680
(sept, H8, J ) 7.0 Hz, 1H), 1.236, 1.256 (d, H9, H10, J ) 7.0
Hz, 3H), 1.250, 1.256 (d, J ) 7.0 Hz, 3H), 3.79, 3.81 (d, H11,
H11′, J ) 15.0 Hz, 1H), 3.30, 3.40 (d, J ) 15.0 Hz, 1H), 1.4-
2.5 (aliphatic protons, H14, H14′, H15, H16, H16′, H17, H17′,
7H), 0.89, 0.92 (s, H19, H20, 3H), 1.070, 1.085 (s, 3H). 13C
NMR (125.6 MHz, CDCl3): 9.92, 9.94, 96.33, 96.35 (Cp*),
13.90, 13.95 (C1), 111.25, 111.32 (C2), 85.88, 86.04 (C3), 88.82,
88.82 (C4), 95.39, 95.53 (C5), 80.40, 80.89 (C6), 119.49, 119.96
(C7), 30.31, 30.38 (C8), 22.41, 22.46, 22.76, 22.81 (C9, C10),
49.57, 50.05 (C11), 58.04, 58.25 (C12), 213.49, 214.00 (C13),
42.47, 42.47 (C14), 42.68, 42.94 (C15), 26.80, 26.86 (C16),
25.30, 25.84 (C17), 48.36, 48.49 (C18), 19.29, 19.31, 19.49,
19.53 (C19, C20).
1363 (m), 702 (m). MS (70 eV, EI): m/z (Irel) 385 (63, M+
H), 371 (100, M+ - CH3), 358 (7, M+ - C2H4), 343 (8, M+
-
-
i-Pr), 233 (14, (Cp*Ru)+ - 4H). Anal. Calcd for [C20H28ORu]:
C, 62.31; H, 7.32. Found: C, 62.00; H, 7.43. (b) As performed
above using 11 instead of 4, yield 47%.
(1S)-[(η6-5-Isop r op yl-2-m eth ylp h en ol)(η5-p en ta m eth yl-
cyclop en t a d ien yl)r u t h en iu m (II)] Tr iflu or om et h a n e-
su lfon a te ((S)-14‚CF 3SO3). 13a (0.2 g, 0.52 mmol) was
treated in acetone with 50 µL (0.52 mmol) of CF3SO3H. The
reddish brown acetone solution was passed over silylated silica,
eluted with acetone, concentrated, and cooled to -78 °C to
(1R,1S)-[(η6-1-Acetyl-5-isop r op yl-2-m eth yl p h en ola te)-
(η5-p en ta m eth ylcyclop en ta d ien yl)r u th en iu m (II)] Tr if-
lu or om eth a n esu lfon a te (16). To 895 mg (1.67 mmol) of 14b
(prepared by reaction of 450 mg (0.84 mmol) of [Cp*RuOMe]2
25
separate 0.264 g (95%) of brown crystals. Fp: 190 °C. [R]546
) +83 (acetone, c ) 1.20 × 10-3 g‚cm-3). 1H NMR (500 MHz,

3958 Organometallics, Vol. 16, No. 18, 1997
Pasch et al.
Ta ble 2. Cr ysta l Da ta , Da ta Collection P a r a m eter s, a n d Con ver gen ce Resu lts of th e X-r a y Str u ctu r e
Deter m in a tion s
6
7‚CF3SO3
7‚BF4
8‚CF3SO3
14‚CF3SO3
formula
fw
cryst syst
space group
a, Å
C20H28ORu
385.52
orthorhombic
P212121 (No. 19)
8.884(3)
9.397(5)
20.806(7)
C21H29F3O4RuS
535.59
C20H29BF4ORu
473.33
C21H29F3O4RuS
535.59
orthorhombic
P212121 (No. 19)
9.819(6)
14.115(5)
16.01(1)
C21H29F3O4RuS
535.59
monoclinic
P21 (No. 4)
8.671(3)
14.437(8)
9.053(2)
102.26(2)
1107(1)
1.606
2
548
8.32
203
monoclinic
P21 (No. 4)
8.872(3)
14.999(6)
30.49(1)
94.87(4)
4043(5)
1.457
monoclinic
P21 (No. 4)
15.054(6)
10.923(4)
15.178(9)
112.64(3)
2304(2)
1.544
b, Å
c, Å
â, deg
V, Å3
1737(2)
1.474
4
800
8.85
213
2219(4)
d
calcd, g cm-3
1.605
Z
8
4
4
F(000)
1812
1096
1096
µ(Mo KR), cm-1
T, K
7.51
203
8.31
213
8.00
293
scan range, deg
total no. of data
no. of unique obsd data
no. of variables
R, Rw, wR2a
GOF
3 < θ < 28
3 < θ < 28
3 < θ < 25
3 < θ < 29
0.5 < θ < 27
8576
5354
14580
3323
10396
3039 (I > 1.0σ(I))
199
0.047, 0.035, na
0.914
1.08
2084 (I > 0.5σ(I))
268
0.0690, 0.053, na
1.050
0.71
8591 (I > 2.0σ(I))
957
0.064, 0.064, na
1.460
1.76
3100 (I > 1.0σ(I))
272
0.029, 0.038, na
1.382
0.34
10005 (all data)
541
0.035, na, 0.083
0.891
0.61
max residuals
density, e Å-3
R ) ∑||Fo| - |Fc||/∑|Fo|. Rw ) [∑w(|Fo| - |Fc|)2/∑w|Fo| ]1/2. wR2 ) [∑w(Fo - Fc2)2/∑w(Fo2)2]1/2
.
a
2
2
with 259 µL (1.68 mmol) of cavacrol and 148 µL (1.68 mmol)
of CF3SO3H in CH2Cl2 at -78 °C in 99% yield) was added, at
-78 °C, 1 equiv of n-butyllithium in 20 mL of Et2O. After
having reached ambient temperature for a short time, the
mixture was recooled to -78 °C and 119 µL (1.67 mmol) of
acetyl chloride was slowly added. The mixture was warmed
to ambient temperature, and the solvent was evaporated.
After extensive drying in vacuo, the residue was dissolved in
CH2Cl2 and LiCl was removed by filtering over Celite. Addi-
tion of ether precipitated an oil, which solidified on drying in
vacuo to an off white powder. Yield: 770 mg (80%). 1H NMR
(500 MHz, CDCl3): 1.83 (s, Cp*, 15H), 5.92 (d, H3, J ) 6.0
Hz, 1H), 5.72 (dbr, H4, J ) 6.0 Hz, 1H), 5.81 (sbr, H5, 1H), 2.01
(s, H1, 3H), 2.60 (sept, H8, J ) 7.0 Hz, 1H), 1.21 (d, H9, H10,
J ) 7.0 Hz, 3H), 1.21 (d, J ) 7.0 Hz, 3H), 2.29 (s, CH3CO,
3H). 13C NMR (125.6 MHz, CDCl3): 9.8, 95.7 (Cp*), 13.1 (C1),
111.0 (C2), 88.3 (C3), 81.3 (C4), 95.0 (C5), 85.2 (C6), 119.3 (C7),
30.6 (C8), 22.3, 22.6 (C9, C10), 168.5 (CdO), 20.2 (CH3CO),
120.6 (q, CF3SO3-, J CF ) 320 Hz).
chromator). Crystal data, data collection parameters, and
convergence results are compiled in Table 2. Only in the case
of 8‚CF3SO3 was an empirical absorption correction on the
basis of azimuthal scans27 applied (min transmission 0.905,
max transmission 0.996) before averaging over symmetry-
equivalent reflections. The structures were solved by Patter-
son syntheses (6, 7‚CF3SO3, 8‚CF3SO3) or direct methods.28 In
the least-squares refinement procedures on F29 in the case of
6-8 and on F2 30 for 14‚CF3SO3, hydrogen atoms were included
in calculated positions with C-H ) 0.98 Å and Uiso(H) )
1.3Ueq(C). Disorder of the trifluoromethyl group was encoun-
tered in the anion of 7‚CF3SO3.
Two independent molecules in the asymmetric unit of
14‚CF3SO3 show pseudoinversion symmetry. Only the oxygen
atoms of the arene ligand result as disordered upon tentative
refinement in the centric supergroup P21/a, and therefore,
during the refinement of this structure considerable correlation
was encountered and is still feasible in displacement param-
eters and details of the molecular geometry. However, the
presence of about 50 significant intensity data with h01, h *
2n, and the fact that single crystals show optical activity
excludes the possibility of a centric space group. Flack’s
enantiomorph polarity parameter22 indicates the correct as-
signment of the enantiomorph: this parameter refined to a
value of 0.05(5).
(1S)-[(η6-(Dip h en ylp h osp h in ito)-5-isop r op yl-2-m eth yl-
ben zen e)(η5-p en ta m eth ylcyclop en ta d ien yl)r u th en iu m -
(II)] Ch lor id e (17). To 100 mg (0.26 mmol) of 13a in 10 mL
of diethyl ether was added 48 µL (0.26 mmol) of ClPPh2 at
ambient temperature. A white solid precipitated from which
the supernatant liquid was decanted. It was washed twice
with ether and dried in vacuo. Yield: 0.125 g (80%). 1H NMR
(250 MHz, CDCl3): 1.87 (s, Cp*, 15H), 6.19 (d, H3, J ) 5.9
Hz, 1H), 5.69 (d, H4, J ) 5.9 Hz, 1H), 6.09 (s, H6, 1H), 2.22 (s,
H1, 3H), 2.52 (sept, H8, J ) 6.9 Hz, 1H), 1.01 (d, H9, H10, J
) 6.9 Hz, 3H), 1.09 (d, J ) 6.9 Hz, 3H), 7.4-7.9 (aromatic
protons, 10H, PPh2).
Ack n ow led gm en t. This work was supported by the
Deutsche Forschungsgemeinschaft and the Fonds der
Chemischen Industrie, Frankfurt/Main. A loan of RuCl3
from J ohnson-Matthey, Reading, England, is gratefully
acknowledged.
(1S)-[(η6-5-Isop r op yl-1-m eth oxy-2-m eth ylben zen e)(η5-
pen tam eth ylcyclopen tadien yl)r u th en iu m (II)] Iodide (18).
To 100 mg (0.26 mmol) of 13a in 5 mL of acetone was added
0.1 mL (1.6 mmol) of MeI, which was warmed 4 h to 45 °C.
The solvent was removed in vacuo and the oily residue was
washed three times with hexane and dried in vacuo to yield
110 mg (80%) of a viscous oil. 1H NMR (250 MHz, CDCl3):
1.82 (s, Cp*, 15H), 1.97 (s, H1, 3H), 5.82 (d, H3, J ) 5.9 Hz,
1H), 5.51 (d, H4, J ) 5.9 Hz, 1H), 6.12 (s, H6, 1H), 2.80 (sept,
H8, J ) 6.8 Hz, 1H), 1.17 (d, H9, H10, J ) 6.8 Hz, 3H), 1.24
(d, J ) 6.8 Hz, 3H), 3.81 (s, OMe, 3H). 13C NMR (62.7 MHz,
CDCl3): 10.7, 94.2 (Cp*), 13.4 (C1), 110.2 (C2), 88.4, 82.7, 72.4
(C3, C4, C6), 89.6 (C5), 131.0 (C7), 30.5 (C8), 22.0, 24.3 (C9,
C10), 58.3 (OMe).
Su p p or tin g In for m a tion Ava ila ble: Tables of X-ray
data, positional and thermal parameters, bond distances, and
bond angles for 6, 7‚CF3SO3, 7‚BF4, 8‚CF3SO3, and 14‚CF3-
SO3 (39 pages). Ordering information is given on any current
masthead page.
OM960961F
(27) North, A. C. T.; Phillips, D. C.; Mathews, F. S. Acta Crystallogr.
1968, A24, 351.
(28) Sheldrick, G. M. SHELXS86, Program for Structure Solution;
University of Go¨ttingen: Go¨ttingen, Germany, 1986.
(29) Frenz, B. A. Enraf-Nonius SDP, Version 5.0; Enraf-Nonius:
Delft, The Netherlands, 1989.
(30) Sheldrick, G. M. SHELXL93, Program for Structure Refinement;
University of Go¨ttingen: Go¨ttingen, Germany, 1993.
(31) Spek, A. L. University of Utrecht, Utrecht, The Netherlands,
1994.
X-r a y Str u ctu r e Deter m in a tion s. Geometry and inten-
sity data were collected on an Enraf-Nonius CAD4 diffracto-
meter with Mo KR radiation (λ ) 0.7107 Å, graphite mono-