Oxodienyl/alkyne coupling reactions in half-open ruthenocenes(II) and related species of Ru(IV)

Article abstract of DOI:10.1021/om050018o

The synthesis of the oxopentadienyl compound by chromatography on neutral deactivated alumina of Cp*Ru(1-4-μ-CH₂CHCHCHOSiMe ₃)Cl was studied. It was shown that the reactions always require an excess of the alkyne, and the diphenylacetylene is more selective compared to the dimethyl acetylenedicarboxylate. It was found that the diphenylacetylene derivatives are very stable, whereas the dimethylacetylenedicarboxylate analogues are less stable and can be easily hydrolyzed in solution. The Cp*Ru(pentadienyl) class of compounds was found to be capable of supporting a rich variety of substituted pentadienyl ligands, which can allow a greater understanding of the electronic nature of the pentadienyl ligands.

Full text of DOI:10.1021/om050018o

Organometallics 2005, 24, 2875-2888
2875
Oxodienyl/Alkyne Coupling Reactions in Half-Open
Ruthenocenes(II) and Related Species of Ru(IV)
M. Esther Sa´nchez-Castro, Armando Ramirez-Monroy, and
M. Angeles Paz-Sandoval*
Departamento de Quı´mica, Centro de Investigacio´n y de Estudios Avanzados del IPN,
Apartado Postal 14-740, Me´xico 07000, D.F., Me´xico, and Av. IPN # 2508,
San Pedro Zacatenco, Me´xico 07360, D.F., Me´xico
Received January 10, 2005
A successful synthesis of Cp*Ru(η5-CH2CHCHCHO) (1) was obtained by chromatography
on neutral deactivated alumina of Cp*Ru(1-4-η-CH2CHCHCHOSiMe3)Cl (2). The dispro-
portionation reaction of 2 affords compounds 1 and Cp*Ru(1-3-η-endo-syn-CH2CHCHCHO)-
Cl2 (3). Reaction of compound 1 with diphenylacetylene affords compounds Cp*Ru[1-5-η-
syn-CH(Ph)C(Ph)CHCHCH(CHO)] (6), Cp*Ru[1,4,5-η-C(Ph)C(Ph)CH2CHCH2]CO (7), Cp*Ru(1-
3-η-CH2CHCHCHO)(η2-PhCtCPh) (8), and compounds with cyclic structures, such as
Cp*Ru[1,6,7,10,11-η-CH(CH)4CCHC(Ph)CH(CH)2C(O)CH(C6H4)CH(Ph)] (9) and Cp*Ru[3,4,5-
η-C(Ph)C(Ph)CHCHCHC(O)](η2-PhCHdCHPh) (10). Reaction of compound 3 with diphenyl-
acetylene shows the syn-aldehyde derivative 6, as well as the corresponding kinetic isomer
11, in which the terminal aldehyde group is in anti-position. Treatment of [Cp*RuCl2]2 with
CH2CHCHCHOSiMe3 affords compound Cp*Ru[1-3-η-endo-syn-(Me)CHCHCH(OEt)]Cl2 (5).
The Ru(IV) complex 5 reacts with diphenylacetylene to give the cyclic 1,2-diphenyl-3-
methylcyclopentadienyl complex Cp*Ru[η5-C(Ph)C(Ph)C(Me)CHCH] (12). The investigation
of the reactivity of the 2,4-dimethyl-oxopentadienyl of Cp*Ru[η5-CH2C(Me)CHC(Me)O] (4)
with excess of diphenylacetylene or dimethyl acetylenedicarboxylate showed the oxopenta-
dienyl/alkyne coupling products Cp*Ru[1-5-η-syn-CH(Ph)C(Ph)CHC(Me)CH(COMe)] (13)
and Cp*Ru[1-5-η-syn-CH(COOMe)C(COOMe)CHC(Me)CH(COMe)] (16), along with small
amounts of Cp*Ru[1-5-η-syn-CH(Ph)C(Ph)CHC{CH2C(Ph)CH(Ph)}CH(COMe)] (14) and
Cp*Ru[1-5-η-syn-CH(COOMe)C(COOMe)CHC{CH2C(COOMe)CH(COOMe)}CH(COMe)] (17),
which are products of a second coupling reaction through the activation of one of the C-H
bonds of the 2-methyl substituent. Crystallographic studies are reported for compounds 6,
9, 13, 14, and 17. Cp*Ru[1-5-η-CH2C(Me)CHC{CH2C(Me)2CH2C(O)}CH] (18) was also
studied in solid state and in solution.
Introduction
venient precursors of substituted cyclopentadienones
from reactions of compounds with labile coordinated
ligands [Cp′Ru(CO)(MeCN)2] [Cp′ ) Cp, Cp*] with
various alkynes11 and a variety of examples of the
ruthenium-alkyne chemistry have been reported. Some
of the latter include (a) the addition of phenyl and
diphenylacetylene to the cationic complex [CpRu{(k1-
P)(4-5-η)-PPh2CH2CH2CHdCH2}(MeCN)]PF6, which
affords η4-butadiene compounds [CpRu{(k1-P)(4-7-η)-
PPh2CH2CH2CHdCHCR1dCHR2}]PF6;12 (b) the cross-
addition of acetylenes to the coordinated olefin in the
chelate neutral ruthenium complex Ru(1-5,9-10-η-C5-
Me4CH2OCH2CHdCH2)(CO)Cl, which gives the corre-
sponding cationic diene chelates;13 (c) a number of
specific reactions related to the bis-insertion process of
There is widespread interest in organoruthenium
reactions with alkynes,1 especially terminal and internal
alkynes, which involve hydrogen, alkyl, aryl, or alkoxy-
carbonyl substituents, because such systems could
induce insertion reactions in a variety of chloro- or
hydrido-ruthenium(II)2-10 and -(IV)4 complexes. Con-
* To whom correspondence should be addressed. E-mail:
mpaz@cinvestav.mx.
(1) Davies, S. G.; McNally, J. P.; Smallridge, A. J. Adv. Organomet.
Chem. 1990, 30, 1.
(2) Masuda, K.; Ohkita, H.; Kurumatani, S.; Itoh, K. Organometal-
lics 1993, 12, 2221, and references therein.
(3) Werner, H.; Esteruelas, M. A.; Otto, H. Organometallics 1986,
5, 2295.
(4) Older, C. M.; Stryker, J. M. Organometallics 2000, 19, 2661, and
references therein.
(5) (a) Lutsenko, Z. L.; Aleksandrov, G. G.; Petrovskii, P. V.;
Shubina, E. S.; Andrianov, V. G.; Struchkov, Y. T.; Rubezhov, A. Z. J.
Organomet. Chem. 1985, 281, 349. (b) Lutsenko, Z. L.; Petrovskii, P.
V.; Bezrukova, A. A.; Rubezhov, A. Z. Bull. Acad. Sci. USSR Chem.
Sci. 1988, 4, 855.
(9) (a) Torres, M. R.; Vegas, A.; Santos, A. J. Organomet. Chem.
1987, 326, 413. (b) Torres, M. R.; Vegas, A.; Santos, J.; Ros, A. J.
Organomet. Chem. 1986, 309, 169.
(10) Campion, B. K.; Heyn, R. H.; Tilley, T. D. Organometallics 1990,
9, 1106.
(6) Crocker, M.; Dunne, B. J.; Green, M.; Orpen, A. G. J. Chem. Soc.
Dalton 1991, 1589.
(11) Ru¨ba, E.; Mereiter, K.; Soldouzi, K.; Gemel, C.; Schmid, R.;
Kirchner, K.; Bustelo, E.; Puerta, M. C.; Valerga, P. Organometallics
2000, 19, 5384.
(12) Slugovc, C.; Mereiter, K.; Schmid, R.; Kirchner, K. Organome-
tallics 1999, 18, 1011.
(7) Older, C. M.; Stryker, J. M. J. Am. Chem. Soc. 2000, 122, 2784.
(8) Older, C. M.; Stryker, J. M. Organometallics 1998, 17, 5596, and
references therein.
10.1021/om050018o CCC: $30.25 © 2005 American Chemical Society
Publication on Web 05/05/2005

2876 Organometallics, Vol. 24, No. 12, 2005
Sa´nchez-Castro et al.
Scheme 1
dimethyl acetylenedicarboxylate with an alkenylruthe-
nium complex;9a and (d) the transformation of Ru(IV)
allyl complexes to their corresponding Ru(II) butadiene
when the CpRu(η3-crotyl)Cl2 is eluted in a silica gel
column and a methyl C-H bond is activated to give
CpRu(η4-butadiene)Cl. This conversion depends on the
retention time on a silica gel column and on the
character of the supports used.14 In the field of mecha-
nistic studies, the cotrimerization between a coordinated
diene and two acetylene molecules, by means of the
Cp*Ru+ fragment and [4+2] cyclodimerization, has been
published.2 Current extensive studies on the properties
and reactivity of several metal-mediated allyl/alkyne
cycloaddition reactions using cationic late transition
metal complexes of the form [(CnRn)M(η3-allyl)(η2-
alkyne)]+ [Co, Rh, Ir, n ) 5; Ru, Os, n ) 6] have allowed
the preparation of substituted η5-cyclopentadienyl4,5a,8,15
and η5-cycloheptadienyl complexes.4,16 However, in the
case of the coordinated hexamethylbenzene complex (η6-
hexamethylbenzene)Ru(allyl)(OTf) a demethylation of
the aromatic ring has also been observed. In particular,
coupling reactions with neutral ruthenium(II) showed
that stable intermediates, such as Cp*Ru(η3-allyl)(η2-
alkyne) [alkyne ) diphenylacetylene, 2-butyne, 1-(tri-
methylsilyl)propyne, and bis(trimethylsilyl)acetylene
(BTMSA)], have been isolated.4 These intermediates
(with the exception of BTMSA) suffer an allyl/alkyne
coupling produced by heating, which results in the
formation of the acyclic 1,2-disubstituted η5-pentadienyl
complexes for alkyl- and aryl-substituted alkynes rather
than cycloadducts, via an unsaturated σ,π-vinyl-olefin
complex. This was demonstrated when the Cp*Ru(η3-
exo-allyl)(η2-alkyne) (alkyne ) diphenylacetylene or
2-butyne) under carbon monoxide suppressed the for-
mation of the corresponding η5-pentadienyl complex and
Cp*Ru[1,4,5-η-C(R)C(R)CH2CHCH2](CO) (R ) Me, Ph)17
were isolated. These studies establish that the coupling
of some mixed alkynes is particularly facile and that
the presence of alkyl substituents on the η3-allyl ligand
complicates the allyl/alkyne reactivity manifold.4
the oxopentadienyl ligands is established in the reaction
of diphenylacetylene with Ru(II) compounds Cp*Ru(η5-
CH2CHCHCHO) (1) and Cp*Ru[η5-CH2C(Me)CHC-
(Me)O] (4). The molecular structures of the resulting
highly functionalized η5-pentadienyl complexes are
reported. The Ru(IV) oxodienyl complexes Cp*Ru(1-3-
η-endo-syn-CH2CHCHCHO)Cl2 (3) and Cp*Ru[1-3-η-
endo-syn-(Me)CHCHCH(OEt)]Cl2 (5) react with diphen-
ylacetylene to afford acyclic and cyclic ruthenocene
complexes, respectively. The reaction of compound 4
with diphenylacetylene and dimethyl acetylenedicar-
boxylate gives evidence of one and two coupling reac-
tions in each case. The unexpected compound Cp*Ru[1-
5-η-CH2C(Me)CHC{CH2C(Me)2CH2C(O)}CH] (18) is
described and related to the half-open metallocenes
which bear the functional group Cp*Ru(R-6-oxa-1-5-
η-heptadienyl) (R ) 2-Me, 2,3-C6H12) and the optically
active pentadienyl compound Cp*Ru[2-methyl-4,5-(di-
methyl-bicyclo[3.1.1]heptane)1-5-η-pentadienyl].19 The
crystal structures of representative compounds are
presented.
Results and Discussion
The oxopentadienyl compound Cp*Ru(η5-CH2CHCH-
CHO) (1) was prepared in 67% yield by chromatography
on neutral deactivated alumina20 of Cp*Ru(1-4-η-CH2-
CHCHCHOSiMe3)Cl (2), which was obtained from the
reaction of (Cp*RuCl2)2 or (Cp*RuCl)4 and trimethylsi-
lyloxybutadiene in THF. The disproportionation reaction
of 2 affords compounds 1 and Cp*Ru(1-3-η-endo-syn-
CH2CHCHCHO)Cl2 (3) (Scheme 1), along with the
spectroscopic evidence of Me3SiCl and their correspond-
ing products, Me3SiOH and Me3SiOSiMe3, from the
hydrolysis and condensation reactions. All these species
The oxodienyl compound Cp*Ru(1-3-η-exo-syn-CH2-
CHCHCHO)(η2-PhCtCPh) (8-exo)18 analogue to Cp*Ru-
(η3-exo-allyl)(η2-PhCtCPh) was obtained from the re-
action of diphenylacetylene with the butenyloxy dimer
[Cp*Ru-µ-1,2,5-η-CH2CH(CH2)2O)]2, and it will be com-
pared to Cp*Ru(1-3-η-endo-anti-CH2CHCHCHO)(η2-
PhCtCPh) (8-endo), which was isolated in this work.
We describe herein a comparative study of the reac-
tivity of the different oxidation states of Cp*Ru(II) or
-(IV) complexes, as well as the influence on the allyl and
oxodienyl ligands coordinated to the Cp*Ru complexes
toward diphenylacetylene and dimethyl acetylenedicar-
boxylate. The influence of the methyl substituents on
1
were carefully studied by H, 13C, and 29Si NMR.21
Complete characterization was carried out for com-
pounds 1, 2, and 3 (Tables 1 and 3).
The isolation of compound 1 is particularly interesting
because it has been reported that the preparation of
methyl-substituted oxopentadienyl compounds such as
Cp*Ru(η5-oxopentadienyl) [oxopentadienyl ) 2,4-Me2-
η5-C4H3O (4), 3,5-Me2-η5-C4H3O] has been obtained from
(Cp*RuCl)4 and the appropriate enone or enal,22 whereas
Cp*Ru(3-Me-η5-C4H4O) has also been isolated, but in
this case, along with the 2-methylallyl complex [Cp*Ru-
(η3-CH2C(Me)CH2)CO]. Similar reactions designed to
prepare analogous species with fewer methyl groups
(13) Gusev, O. V.; Kal’sin, A. M.; Morozova, L. N.; Petrovskii, P. V.;
Lyssenko, K. A.; Tok, O. L.; Noels, A. F.; O’Leary, S. R.; Maitlis, P. M.
Organometallics 1999, 18, 5276.
(14) Masuda, K.; Saitoh, M.; Aoki, K.; Itoh, K. J. Organomet. Chem.
1994, 473, 285.
(15) (a) Schwiebert, K. E.; Stryker, J. M. Organometallics 1993, 12,
600. (b) Nehl, H. Chem. Ber. 1993, 126, 1519.
(16) (a) Dzwiniel, T. L.; Etkin, N.; Stryker, J. M. J. Am. Chem. Soc.
1999, 121, 10640. (b) Etkin, N.; Dzwiniel, T. L.; Schweibert, E.; Stryker,
J. M. J. Am. Chem. Soc. 1998, 120, 9702. (c) Schwiebert, K. E.; Stryker,
J. M. J. Am. Chem. Soc. 1995, 117, 8275.
(19) Bosch, H. W.; Hund, H.-U.; Nietlispach, D.; Salzer, A. Orga-
nometallics 1992, 11, 2087.
(20) Chen, J.; Daniels, L. M.; Angelici, R. J. J. Am. Chem. Soc. 1990,
112, 199.
(17) Older, C. M.; Stryker, J. M. Organometallics 2000, 19, 3266,
and references therein.
(18) Koelle, U.; Kang, B. S.; Thewalt, U. Organometallics 1992, 11,
2893.
(21) Sa´nchez-Castro M. E.; Paz-Sandoval, M. A. Unpublished re-
sults.
(22) Trakarnpruk, W.; Arif, A. M.; Ernst, R. D. Organometallics
1992, 11, 1686.

Coupling Reactions in Half-Open Ruthenocenes(II)
Organometallics, Vol. 24, No. 12, 2005 2877
Table 1. 1H NMR Dataa for Compounds 1-5
compound
H1a
2.30 (d)b
H1s
H2 or Me2
4.28 (m)
H3
H4 or Me4
6.90 (s,br)
Cp*
1
3.37 (d) JH1s,H2 ) 8.5
4.61 (d) JH2,H3 ) 6.6
1.62 (s)
JH1a,H2 ) 10.2
1.72 (d)c
3.37 (d) JH1s,H2 ) 8.3
4.46 (m)
4.88 (d) JH2,H3 ) 5.8
6.88 (s,br)
1.84 (s)
1.38 (s)
JH1a,H2 ) 10.9
1.75 (dd)b
2d
2.85 (dd) JH1a,H1s ) 1.8
JH1s,H2 ) 7.7
3.75 (ddd)
4.50 (dd) JH2,H3 ) 5.7
JH3,H4 ) 7.5
4.98 (d)
JH3,H4 ) 7.5
JH1a,H1s ) 1.8
JH1a,H2 ) 10.5
JH2,H3 ) 5.8
JH2,H1s ) 7.7
JH1a,H2 ) 10.5
4.17 (m)
1.35 (dd)c
2.96 (dd) JH1a,H1s ) 1.7
JH1s,H2 ) 7.7
4.60 (m)e
4.61e
1.61 (s)
JH1a,H1s ) 1.7
JH1a,H2 ) 10.6
1.58 (d)b
3
4.08 (d) JH1s,H2 ) 6.2
4.36 (d) JH1s,H2 ) 6.4
5.83 (m)
1.99 (dd) JH2,H3 ) 9.5
JH3,H4 ) 7.1
2.55 (dd) JH2,H3 ) 9.5
JH3,H4 ) 7.1
10.28 (d)
1.00 (s)
1.64 (s)
JH1a,H2 ) 9.7
JH3,H4 ) 7.3
10.14 (d)
2.40 (d)c
6.15 (ddd)
JH1s,H2 ) 6.2
JH2,H3 ) 9.7
JH1a,H2 ) 9.7
1.96 (s)
1.99 (s)
5.03 (t)
JH1a,H2 ) 9.7
JH3,H4 ) 7.1
4f
2.28 (s)b
1.58 (s)c
1.92 (m)b
3.25 (s)
3.10 (s)
4.68 (s)
4.80 (s)
1.48 (s)
1.54 (s)
H4′, H4′′ 4.08 (m)
3.52 (m)
1.59 (s)
1.68 (s)
1.11(s)
5g
1.64 (d) JH1a,Me1s ) 6.2
4.90 (d) JH2,H3 ) 8.8
JH1a,H2 ) 9.1
JH2,H3 ) 9.1
2.56 (dq)c
JH1a,Me1s ) 6.2
JH1a,H2 ) 9.6
1.62 (d) JH1a, Me1s ) 6.2
5.00 (t)
JH1a,H2 ) 9.3
JH2,H3 ) 9.3
5.37 (d) JH2,H3 ) 8.8
H4′, H4′′ 4.05 (m)
3.91 (m)
1.58 (s)
a For numbering see corresponding schemes. δ (ppm); H1a ) hydrogen 1-anti; H1s ) hydrogen 1-syn; J ) coupling constant in Hz, (d)
doublet; (s) singlet; (q) quartet; (m) multiplet; (br) broad. b C6D6. c CDCl3. d SiMe3: 0.31 (s)b and 0.21 (s)c; 29Si NMR data for this compound:
22.9b and 23.3c ppm. e Overlapped signals; f Reference 28; g Me5: 1.12b (overlapped with Cp*signal); 1.33c (t) JH4,H5 ) 7.0.
have led to only CO extrusion and coordination, as
observed for the 2-methylallyl derivative.23 Actually, the
reaction between [Cp*RuCl]4 with crotonaldehyde, in
the presence of potassium carbonate, led to the exclusive
isolation of (Cp*Ru)2(µ2-HC2Me)(µ2-CO), instead of the
expected Cp*Ru(η5-CH2CHCHCHO) (1).22
6 in 35% yield, and the third fraction showed the
formation of [Cp*Ru(1-3-η-endo-anti-CH2CHCHCHO)-
(η2-PhCtCPh)] (8-endo), Scheme 3.
Compounds 7 and 8-endo were formed during the
chromatographic procedure and, interestingly, the σ,π-
vinyl-olefin complex 7 was formed by the extrusion and
coordination of the CO of compound 1, as described in
Scheme 4.
Compound 7 is remarkably stable, and it had already
been isolated by Stryker et al. from the reaction of
[Cp*Ru(η3-exo-CH2CHCH2)(η2-PhCtCPh)] under carbon
monoxide atmosphere (60 psig), which gave indirect
evidence of the intermediate species proposed in the
formation of the pentadienyl complexes Cp*Ru[η5-
C(Ph)C(Ph)CHCHCH2].17
According to spectroscopic NMR data (Tables 2 and
4), the yellow complex 8-endo has the oxodienyl ligand
in η3-endo-anti conformation and coordinated η2-di-
phenylacetylene. Compound 8-endo is an analogue to
the allyl complex [Cp*Ru(η3-exo-CH2CHCH2)(η2-PhCt
CPh)],4,17 but contrastingly, it does not undergo oxodi-
enyl/alkyne coupling upon warming at 60 °C in C6D6
(12 h) or 50 °C in CDCl3 (24 h) to form the corresponding
open-chain η5-pentadienyl complex 6. After monitoring
the reaction of 8-endo in C6D6, there was evidence of
only free diphenylacetylene along with a singlet at 1.30
ppm for the Cp* ligand, whereas 8-endo in CDCl3
showed the formation of compound 3 and free diphenyl-
acetylene. According to these results, compound 8-endo
is not a precursor of 6 in the reaction of 1 with
diphenylacetylene. However, heating [Cp*Ru(1-3-η-exo-
syn-CH2CHCHCHO)(η2-PhCtCPh)] (8-exo)18 with the
oxodienyl ligand in an η3-exo-syn conformation and
coordinated η2-diphenylacetylene shows that it is indeed
an intermediate, evidencing the influence of the con-
formation of the η3-oxodienyl ligand in these coupling
reactions.25
An equilibrium between the oxodienyl complex with
a coordinated η2-crotonaldehyde Cp*Ru(1-3-η-CH2-
CHCHCHO)(1-2-η-(Me)CHCHCHO) and the oxopen-
tadienyl complex Cp*Ru(η5-CH2CHCHCHO) (1) has
been observed manifested by 1H NMR from the reaction
of [Cp*Ru(OMe)]2 with crotonaldehyde, but the η5-
complex has not been isolated. Koelle et al. mentioned
that such ruthenium oxopentadienyl complexes had
been isolated only with stabilizing methyl groups.24
We have found that once compound 1 has been
isolated, it is reasonable stable, and in fact the first
discussion of its chemistry is presented in this paper.
(a) Reactions of Cp*Ru(η5-CH2CHCHCHO) (1)
with Diphenylacetylene. Treatment of 1 with an
excess of PhCtCPh (1:2) under reflux of THF for 24 h
afforded, according to the 1H NMR of the crude of
reaction, compound 1 (small amount), Cp*Ru[1-5-η-
syn-CH(Ph)C(Ph)CHCHCH(CHO)] (6) as a major prod-
uct, and PhCtCPh, Scheme 2.
After evaporation of the solvent and purification by
chromatography over neutral alumina, there were three
different fractions that were eluted with hexane, hex-
ane/diethyl ether, and diethyl ether, respectively. The
1H NMR showed that, from the first fraction, excess
PhCtCPh along with the compound Cp*Ru[1,4,5-η-
C(Ph)C(Ph)CH2CHCH2]CO (7)17 were obtained and
separated by a second chromatography. The second
fraction showed the exclusive separation of compound
(23) Trakarnpruk, W., Arif, A. M.; Ernst, R. D. Organometallics
1994, 13, 2423.
(24) Koelle, U. Chem. Rev. 1998, 98, 1313, and references therein.

2878 Organometallics, Vol. 24, No. 12, 2005
Sa´nchez-Castro et al.

Coupling Reactions in Half-Open Ruthenocenes(II)
Organometallics, Vol. 24, No. 12, 2005 2879
Table 3. 13C NMR Dataa of Compounds 1-5
6 and 8-exo after recrystallization, with diethyl ether
at room temperature, showed the transformation of
8-exo into compound 6 as yellow crystals, which pre-
cipitated along with red-orange needles of compound 9,
and these were selected manually. The corresponding
crystal structure (vide infra) shows that compound 9 is
formed by the cyclization of the pentadienyl ligand in
6, which gives an η2-coordination, and a second coupling
of diphenylacetylene to the central carbon atom of the
pentadienyl. This second molecule of alkyne is also
coordinated to the metal through two carbon atoms from
one of the phenyl rings and the next carbon atom out of
the ring, which affords an η3-benzyl bond, Scheme 5.
The structural view, as well as selected bond distances
and angles, will be discussed below. Attempts to repro-
duce the formation of compound 9 were unsuccessful.
Compound 8-endo, isolated from a more polar fraction
than 8-exo, was recrystallized in diethyl ether at -5
°C, giving yellow needles in very low yield (2%).
compound
C1
C2
C3
C4
C(Cp*) C(Me,Cp*)
1
55.5c
50.8b
50.9c
66.3b
66.8c
90.8 88.0 123.0
83.7 84.4 108.6
84.2 84.2 107.9
98.6 68.2 201.0
99.1 68.2 201.6
89.4
94.0
11.1
9.5
2d
93.7
9.3
3
106.4
107.5
87.1
9.2
9.8
10.6
9.6
4e
5f
54.8b 101.2 84.0 135.0
16.5
68.2 84.2 127.0
100.2
a δ (ppm). b C6D6. c CDCl3. d SiMe3: 0.52b; 0.08c. e 23.2 (C5), 25.1
(C6); ref 28. f 69.2 (C5), 14.5 (C6).
Scheme 2
Recrystallization of compound 10 with pentane at -78
°C, after a second chromatography on neutral alumina
with diethyl ether as eluent, gave a brown-red solid,
which, according to one- and two-dimensional NMR
experiments, corresponds to the six-membered ring
molecule 10, in which a cis-stilbene is coordinated to
ruthenium, Scheme 5. The 1H NMR spectrum (Table 2,
footnote e) of 10 shows a singlet for the Cp* (1.24 ppm)
and doublets centered at 2.76 and 2.56 with a common
coupling constant of 9.5 Hz, consistent with cis-
hydrogens in the stilbene molecule.26 The COSY experi-
ment shows the corresponding correlation of the three
allylic hydrogens [δ ) 4.11 (d), J4,5 ) 4.6 Hz, H5; δ )
3.74 (dd), J4,5 ) 4.9, J3,4 ) 6.3 Hz, H4; δ ) 3.86 (d), J3,4
) 6.6 Hz, H3]. 13C NMR (Table 4) shows that the olefinic
carbon atoms in the coordinated stilbene are at 61.1 and
51.1 ppm, whereas the noncoordinated double bond of
the “cyclohexa-η3-dienylone” is at 148.5 and 140.0 ppm
and the carbonyl is at 205.3 ppm.
Scheme 3
Scheme 4
(b) Reaction of Cp*Ru(1-3-η-endo-syn-CH2-
CHCHCHO)Cl2 (3) with Diphenylacetylene. Com-
pound 3 treated with excess diphenylacetylene (1:5),
under reflux of THF for 5 h, and in the presence of zinc
as a reducting reagent, gave compound 11, which is an
isomer of compound 6. These isomers differ in the
chemical shifts of the terminal anti hydrogens (H1 and
H4) of the pentadienyl ligand, Table 2 and Scheme 6.
Compound 11 could be partially precipitated from
diethyl ether at -5 °C as orange needles, and after 2 h
in solution of CDCl3 it is transformed into compound 6;
the remaining compound 11 in the presence of diphen-
ylacetylene was treated with neutral alumina chroma-
Scheme 5
(25) Compound 8-exo has been reported.18 The synthesis was
sligthly modified, working at room temperature instead of 40 °C. Our
assignment of the 1H and 13C NMR spectra for 8-exo differs from that
already published.18 [1H NMR (C6D6): 1.04 (d, 9.9, H1anti), 2.88 (d,
6.6, H1syn), 3.95 (ddd, 6.8, 8.4, 9.6, H2), 1.28 (dd, 5.5, 8.3, H3), 9.50
(d, 5.5, H4), 1.37 (s, Cp*), 7.10 (m), 7.25 (t, ∼7.80), 7.32 (t, ∼7.80),
7.85 (dd, 1.25, 5.50), 8.01 (dd, 7.18). 13C NMR (C6D6): 48.1 (C1), 84.0
(C2), 60.7 (C3), 197.4 (C4), 94.4 and 94.7 (PhCCPh), 95.1 (Cp*C), 10.0
(Cp*Me), 127.3, 127.6, 128.9, 131.1, 131.7, 132.2, 132.9 (PhCCPh)].
Compound 8-exo in C6D6 at 45 °C and after 17 h shows, through 1H
NMR, transformation to compound 6 in a 1:0.15 ratio, respectively.
After 2 days, complete conversion of compound 6 is observed. Under
the same conditions, compound 8-exo in the presence of CDCl3 reacts
faster, giving compounds 6 and 3 in a 1:0.35 ratio (17 h), without clear
evidence of 8-exo, and after 2 days the ratio changes to 1:0.5.
(26) Baya, M.; Buil, M. L.; Esteruelas, M. A.; On˜ate, E. Organome-
tallics 2004, 23, 1416.
The amount of diphenylacetylene is crucial in the
species formed, as it was demonstrated that when under
identical experimental conditions but with a different
stoichiometry, a 1:3.5 ratio of 1 and diphenylacetylene
instead of 1:2, compounds 6, 7, 8-exo, 8-endo, Cp*Ru-
[1,6,7,10,11-η-CH(CH)4CCHC(Ph)CH(CH)2C(O)CH-
(C6H4)CH(Ph)] (9), and Cp*Ru[3,4,5-η-C(Ph)C(Ph)CH-
CHCHC(O)](η2-PhCHdCHPh) (10) were obtained (in
small amounts, except compound 6) after chromato-
graphic separation as described in the Experimental
Section. A mixture of diphenylacetylene and compounds

2880 Organometallics, Vol. 24, No. 12, 2005
Table 4. 13C NMR Dataa for Compounds 6-8, 10, and 12-18
Sa´nchez-Castro et al.
compound
C1
C2
C3
C4
C5
C6
C(Cp*) C(Me,Cp*)
Ph or CO, OMe
6
59.6b
102.4
94.0
85.2
61.4
199.0
91.1
91.4
98.5
9.6
10.1
9.6
143.5; 141.0; 131.2 129.5;
128.0; 125.0
59.6c
102.8
151.9
94.6
48.0
85.7
72.8
61.6
48.9
200.6
211.3
143.1; 140.5; 131.0 129.3;
128.6; 128.0 127.9; 124.0
151.6; 142.5; 130.6 129.4;
128.7; 127.7 125.1; 124.1
131.8; 130.9; 128.4; 128.1
131.9; 131.1; 128.8; 127.3;
127.0; 126.8
7
152.3b
8-endo
49.3b
50.1c
97.5
98.1
58.9
59.0
187.0
188.2
96.6
95.5
96.2
9.2
10.0
94.5d
96.5d
205.3
13.0
10e
12
148.5b
90.0c
59.3b
59.5b
140.0
91.2
49.9
85.5
97.0
97.0
74.1
75.6
95.1
96.1
56.8
73.2
60.1
59.9
96.5
89.6
90.9
91.3
9.4
11.1
9.2
135.1, 134.5; 130.6 130.2;
128.7; 127.7 126.3, 125.9
137.6; 136.3; 131.7 128.7;
127.5; 125.9 125.2; 123.4
144.7; 142.3; 131.5 129.9;
124.1
145.7; 144.5; 142.5 142.0;
131.6; 130.1 130.0; 129.9;
129.2 127.3; 126.8
145.3; 142.4; 131.8 129.6;
128.6; 128.3 127.8; 124.1
174.3, 171.3 (CdO); 52.5,
50.6 (OMe)
13f
14g
102.8
103.4
204.4
204.5
9.3
15h
16i
17j
58.1b
43.9b
44.5b
102.0
98.1
96.3
102.2
95.6
95.9
87.2
95.1
96.0
60.6
58.9
57.8
204.5
203.4
203.6
91.0
93.5
94.4
9.8
8.7
8.9
174.2, 170.9, 168.9, 165.7
(CdO) 52.8, 52.4, 51.6, 50.9
(OMe)
18
47.5b
47.1c
97.9 (C),
25.6 (Me)
97.4 (C),
25.2 (Me)
92.0
91.6
95.2 (C),
56.9
56.0
206.8
210.0
89.6
89.4
10.1
9.8
43.9 (C7); 33.8 (C8) 31.3
51.9 (CH2)
95.7 (C),
(C8′)d; 26.4 (C8′′)d
43.1 (C7); 33.6 (C8) 30.9
(C8′)d; 26.0 (C8′′)d
51.0 (CH2)
a δ (ppm); n.o. ) not observed. b C6D6. c CDCl3. d Assignment could be reversed. e 61.1, 51.1, stilbene carbon atoms. f 19.7 (C7), 33.2
(C8). g [C(7): 44.3 (CH2), 138.4 (C), 127.3 (CH)], 33.2 (C8). h 25.3 (C7), 30.5 (C8). i 19.0 (C7), 32.5 (C8). j [(C7): 37.7(CH2), 150.5 (C),
121.6(CH)], 32.5 (C8).
Scheme 6
Scheme 7
tography, affording compound 6 in 15% yield. The same
reaction described in Scheme 6 but after 10 h gave
basically compound 6 in 20% yield. Even though 6 is
the major compound in this reaction, its purification was
not quite efficient in the presence of zinc, so it was better
to isolate compound 6 from the reaction of compound 1
with diphenylacetylene.
(c) Reaction of Cp*Ru[1-3-η-endo-syn-(Me)CH-
CHCH(OEt)]Cl2 (5) with Diphenylacetylene. The
reaction between 5 and excess of diphenyacetylene (1:
5) in the presence of activated zinc under reflux of THF
for 8 h furnished an evident change of color, from orange
to a dark brown-yellow solution, Scheme 7. The crude
of the reaction showed the presence of ethanol and
Cp*Ru[η5-C(Ph)C(Ph)C(Me)CHCH] (12) by 1H NMR.
After chromatography on neutral alumina, and using
hexane as eluent, some white crystals were isolated as
a mixture of compound 12 and diphenylacetylene. The
solubility of both compounds did not allow their separa-
tion. However, it was easy to establish the correspond-
1
ing characterization of 12 by H and 13C NMR (Tables
2 and 4). Similar structures have been obtained by [3+2]
cycloaddition reactions for η5-cyclopentadienyl,5a η5-
pentamethylcyclopentadienyl,15 and η6-arene5,8 com-

Coupling Reactions in Half-Open Ruthenocenes(II)
Organometallics, Vol. 24, No. 12, 2005 2881
Scheme 8
Scheme 9
plexes of the late transition metals with several alkynes.
The product of cyclization was promoted by the presence
of the acetal group in compound 5.
A tentative mechanism of reaction is the formation
of ZnCl2 and the coordination of η2-PhCtCPh followed
by the insertion of the alkyne to give a σ,π-vinyl olefin.
Then, the activation of a C-H bond forms a σ-vinyl, η3-
allyl hydride Ru(IV) complex, which will afford the 1,2-
diphenyl-3-methyl-5-ethoxy-η5-pentadienyl ligand coor-
dinated to a Cp*Ru(II) fragment. The formation of
ethanol from the ethoxy group and one hydrogen atom
of the pentadienyl ligand affords the corresponding
cyclopentadienyl-substituted compound 12.
transformed into the syn-isomer 13, and only in the
presence of activated neutral alumina is it partially
transformed to the anti-isomer 15, Scheme 9. Appar-
ently, this is because of the different steric environments
of 1 and 4. With a methyl group at carbon atom C4, the
repulsion of the carbonyl substituent can interconvert
to the anti position to give more relief to the structure.27
Differentiation between the syn and anti isomers was
derived from the chemical shifts of the terminal protons
of the pentadienyl ligand, H1anti and H5, in compounds
13 [H1anti: 2.49 (s); H5anti: 1.03 (s)] and 15 [H1anti:
3.73 (s); H5syn: 1.91 (s)] and chemical shifts and
coupling constants for compounds 6 [H1anti: 1.89 (s);
H5anti: 2.01 (t, 7.5 Hz); H4: 4.93 (J4,5 ) 7.8, J3,4 ) 6.1)]
and 11 [H1anti: 2.49 (s); H5syn: 2.16 (t, 7.8 Hz); H4:
5.05 (J3,4 ) 6.4, J2,3 ) 7.2)]] (Table 2). The ∆δ ) 0.60
ppm found in compounds 6 and 11 is attributed to the
diamagnetic deshielding of the carbonyl group on the
H1anti. Herein the crystal structure of compound 13 is
reported. The crystal structure of compound 15 was also
obtained; however, its poor quality established only the
position of the carbonyl group (vide infra).
(d) Reactions of Cp*Ru[η5-CH2C(Me)CHC(Me)O]
(4) with Diphenylacetylene and Dimethyl Acety-
lenedicarboxylate. Novel functionalized yellow air-
stable pentadienyl complexes were obtained from the
reaction of 4 with diphenylacetylene, and it was possible
to isolate the coupling and the double-coupling reaction
products 13 and 14, respectively, Scheme 8.
Upon variation of the complex 4/diphenylacetylene
ratio, it was found that a 3-fold excess of diphenylacety-
lene was necessary in order to achieve a better yield of
13. However, it is also interesting to mention that the
neutral alumina (Brockmann, Activity I) plays an
important role in the chromatographic treatment, af-
fording different results if it is deactivated previously
(5% w/w N2-saturated water)20 or not. Then, we exten-
sively varied the amount of the alkyne used, time of the
reaction, and the type of chromatographic support, to
obtain more information on this reaction system. Under
similar conditions of stoichiometry and time (1:3 ratio,
21 h), it was observed that neutral alumina, without
any treatment, afforded compound 13 in 48% yield,
whereas deactivated alumina improved the yield to
85.4% yield. Also, when using the latter, it was possible
to avoid the formation of isomer 15 (vide infra).
After 24 h, compound 13 in toluene (110 °C) or in the
presence of neutral alumina in diethyl ether (room
temperature) resulted in no decomposition or evidence
of formation of compound 15, whereas compound 13 in
the presence of neutral alumina under reflux of toluene
(6.5 h) gives evidence of compound 15.
1
The H NMR of the crude of the reaction of 4 and
Compound 14 is always formed as a minor product;
then, to fully characterized this compound (Tables 2 and
4), several reactions were carried out. The formation of
14 implies the activation of the C-H of the methyl
group in C4 and the addition of another molecule of
diphenylacetylene with the corresponding carbon-
carbon bond formation, which affords a new, highly
excess diphenylacetylene showed the presence of com-
pounds 4, 13, and traces of 14, as well as diphenylacety-
lene. After chromatography with neutral activated
alumina, the isolation of three different fractions gave
compounds 13, 14, and 15, respectively, which could be
purified by TLC techniques.
The spectral data (Tables 2 and 4) show that complex
15 is the isomer of 13, where only the H5 of 13 is
exchanging positions (Table 2). It is interesting to
compare these isomers to the analogous 11 and 6.
Whereas the anti-isomer 11 can easily interconvert into
the thermodynamically more stable syn-isomer 6, the
2,4-dimethyl-substituted complex 4 can be directly
(27) The crystal structure of Cp*Ru[1-5-η-anti-CH(COOMe)C-
(COOMe)CHC(CMe3)CH(COCMe3)] also gave evidence of the exclusive
preference of an anti conformation of the COCMe3 group in the
pentadienyl ligand. The centroid distances for Cp*-Ru and pentadi-
enyl-Ru are 1.855 and 1.623 Å, respectively, and the dihedral angle
formed by LSQ-planes is 1.06°. Ramirez-Monroy, A.; Sa´nchez-Castro,
M. E.; Paz-Sandoval, M. A. Unpublished results.

2882 Organometallics, Vol. 24, No. 12, 2005
Sa´nchez-Castro et al.
Scheme 10
Scheme 11
substituted pentadienyl ligand coordinated to the Cp*Ru
fragment.
poor alkyne dimethyl acetylenedicarboxylate (MeO2CCt
CCO2Me ) DMAD) in a 1:3 ratio, Scheme 10, Tables 2
and 4. The reaction is not selective, and in the presence
of excess DMAD, compound 17 is favored (30% yield)
compared to 16 (13% yield), which contrasts with the
chemistry described for 13 and 14. To avoid the forma-
tion of more products during the chromatography,
deactivated neutral alumina was always used in the
purification of these complexes, and in fact, the forma-
tion of an analogue isomer, such as 15 in the reaction
of 4 with the DMAD alkyne, was not observed.
Possible reaction sequences for the formation of
compounds 13, 14, 16, and 17 are shown in Scheme 11.
A tentative mechanism via an unsaturated σ,π-vinyl-
olefin intermediate is proposed, which depending on the
formation of Ru(IV) complexes with a syn or anti
An attempted synthesis of the hydrocarbon pentadi-
enyl analogue of 13 was unsuccessful. Cp*Ru(2,4-
dimethyl-η5-pentadienyl) did not react with diphenyl-
acetylene, even under different and stronger conditions
than those described for compound 4. The presence of
the oxygen atom in the oxopentadienyl complex 4 is
determinant in the reactivity toward diphenylacetylene,
which favors the attack of the alkyne at the methylene
terminal carbon atom. This is due to the higher elec-
tronegativity on the oxygen compared to the homoge-
neous electronic environment found in the pentadienyl
complex.
Similar to the synthesis of 13 and 14, compounds 16
and 17 were prepared by treating 4 with more electron-

Coupling Reactions in Half-Open Ruthenocenes(II)
Organometallics, Vol. 24, No. 12, 2005 2883
Table 5. X-ray Data Collection Parameters for Compounds 6, 9, 13, 14, 17, and 18
6
9
13
14
17
18
formula
fw
C
28H30ORu
C42H40ORu
661.85
C30H34ORu
511.64
C44H44ORu
689.86
C28H36O9Ru
617.64
trigonal
R3h
44.0085(5)
44.0085(5)
8.69690(10)
90
90
120
14587.1(3)
18
C22H32ORu
413.55
monoclinic
P21/c
7.5664(15)
13.433(3)
20.191(4)
90
98.97(3)
90
2027.1(7)
4
483.59
cryst syst
space group
a (Å)
monoclinic
Cc
12.0777(3)
11.3100(3)
16.7043(5)
90
100.6340(1)
90
2242.60(11)
4
triclinic
P1h
monoclinic
P21/n
monoclinic
P21/c
9.8991(10)
10.9444(10)
17.9392(10)
74.28(2)
82.94(2)
69.57(2)
1752.3(3)
2
16.7107(4)
7.5123(2)
20.7493(6)
90
101.9560(1)
90
2548.27(12)
4
10.9164(3)
17.8403(6)
18.6151(5)
90
106.395(2)
90
3477.91(18)
4
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
cryst size (mm)
0.3 × 0.1 × 0.1 0.3 × 0.1 × 0.1
0.2 × 0.1 × 0.1 0.1 × 0.1 × 0.03 0.3 × 0.1 × 0.1 0.3 × 0.2 × 0.1
Dcalc (g cm-3
)
1.432
1.325
253
1.334
253
1.318
203
Kappa CCD
52.06
17034
6775
4983
580
0.0448
0.0793
1.101
1.266
208
Kappa CCD
54.98
44857
7399
5552
373
0.0458
0.1102
1.089
1.355
203
Kappa CCD
55.30
16275
4672
3174
257
0.0388
0.0748
1.009
temp (K)
198
diffractometer
Kappa CCD
54.96
Enraf-Nonius CAD4 Kappa CCD
2θ (max) (deg)
50.94
6497
6497
2589
420
0.0493
0.1038
0.886
54.98
21215
5819
4072
308
0.0504
0.0950
1.054
no. of reflns collcd
no. of indpt reflns
10278
4471
no. of indpt obsd (4σ) on F2 4148
params
268
a
final R1
0.0443
0.1118
1.083
a
final wR2
GOOF
2
1/2
a R1 ) ∑||Fo| - |Fc||/∑|Fo|; wR2 ) [∑w(Fo - Fc)2/∑wFo
]
are given for observed data.
orientation of the carbonyl group of the oxodienyl ligand
will afford the single or double alkyne coupling reac-
tions, respectively. At first stage, there is no evidence
of a Cp*Ru(2,4-dimethyl-η3-oxodienyl)(η2-alkyne) as re-
active intermediate (see compounds 8-endo, 8-exo, vide
supra), and a direct coupling of the alkyne to the
oxopentadienyl coordinated ligand is proposed. Also, it
should be mentioned that apparently 13 is not a
precursor of 14, since heating 13 with diphenylacetylene
in a 1:3 ratio (65-70 °C for 135 h) results in no evidence
of the double-coupling reaction.
It is important to mention that purification of all
compounds is complicated, because even though differ-
ent chromatographic procedures with different kinds of
supports were carried out, several products were ob-
tained. Instead of being purified, they always were
transformed.
Attempts to react compound 4 with bis-trimethylsi-
lylacetylene and phenylacetylene had limited success.
The former did not react presumably due to the steric
bulk on the SiMe3 groups, and the latter showed that
the presence of an acidic hydrogen reacts smoothly, but
without any selectivity, making the isolation of the
different coupling products from the reaction mixture
difficult.
(e) Reaction of (Cp*RuCl)4 with Lithium Oxo-
pentadienide to Afford Cp*Ru[η5-CH2C(Me)CHC-
(Me)O] (4) and Cp*Ru[1-5-η-CH2C(Me)CHC{CH2C-
(Me)2CH2CO}CH] (18). In our own earlier studies, we
published an improved route to synthesize Cp*Ru(2,4-
dimethyl-η5-oxopentadienyl) (4).28 The oxopentadienyl
compound 4 was formed, at -78 °C, from the corre-
sponding lithium oxopentadienide and (Cp*RuCl)4 in
80% yield. The purification was carried out extracting
the product with hexane, and the resulting solution was
concentrated and chromatographed on a neutral alu-
mina column (5 × 1.5 cm) with a mixture of hexane/di-
ethyl ether (8:2) as the eluant. Now, running the same
experiment but extracting with diethyl ether instead of
hexane, a yellow diethyl ether solution was obtained and
purified through chromatographic separation on a 25
× 1.5 cm neutral alumina column. After elution with
an 8:2 mixture of hexane/diethyl ether, a yellow band
corresponding to compound 4 was collected, and then,
a second yellow band, eluted with diethyl ether, afforded
Cp*Ru[1-5-η-CH2C(Me)CHC{CH2C(Me)2CH2C(O)}-
CH] (18) as a yellow solid in a poor yield and always in
the presence of the less polar compound 4. Attempts to
separate these products, 4 and 18, were unsuccessful.
However, when the mixture of 4 and traces of 18 was
reacted in the presence of diphenylacetylene, 4 was
practically consumed to give 13, and 18 remained
without any transformation. Purification of 18 is de-
scribed in the Experimental Section, being isolated from
the reaction of compound 4 with diphenylacetylene. A
tentative mechanism may involve the reaction of lithium
oxopentadienide with mesityl oxide to give the corre-
sponding unsaturated enone, which in the presence of
LDA and (Cp*RuCl)4 affords the interesting chiral
compound 18. To probe if the stoichiometry could afford
compound 18 in higher yields, the reaction of (Cp*RuCl)4
was carried out in excess lithium oxopentadienide (1:2,
respectively) with basically the same results obtained
with the stoichiometric ratio.
Structural Studies of Compounds 6, 9, 13, 14, 17,
and 18. The single and double alkyne coupling products
can be further assessed with the aid of the X-ray crystal
structure, as it will be shown for the diphenylacetylene
derivatives 6, 9, 13, and 14 and for the DMAD in the
case of 17. Crystal data for compounds 6, 9, 13, 14, 17,
and 18 are provided in Table 5.
The structures of 6 and 13 are presented in Figures
1 and 2. Some relevant data are provided in Table 6.
The solid-state structures from a second coupling
reaction of alkynes in half-open ruthenocenes are 9, 14,
and 17. They are presented in Figures 3-5, while
various bonding parameters are included in Tables 7
and 8. Compound 18 is shown in Figure 6, and selected
data are provided in Table 9.
(28) Navarro-Clemente, M. E.; Jua´rez-Saavedra P.; Cervantes-
Va´squez, M.; Paz-Sandoval, M. A.; Arif, A. M.; Ernst, R. D. Organo-
metallics 2002, 21, 592.

2884 Organometallics, Vol. 24, No. 12, 2005
Sa´nchez-Castro et al.
Figure 1. Perspective view of compound 6. Most hydrogen
atoms are omitted for clarity.
Figure 3. Crystal structure of compound 9. Hydrogen
atoms and solvent are omitted for clarity.
Figure 2. Perspective view of compound 13. Most hydro-
gen atoms are omitted for clarity.
Table 6. Selected Bond Lengths (Å) and Bond
Angles (deg) for Compounds 6 and 13
bond distances
13
C1-O1 1.214(9) 1.222(5) O1-C1-C2
bond angles
13
6
6
125.4(5) 125.4(4)
116.7(6) 126.1(4)
126.4(5) 118.9(3)
125.4(5) 128.7(4)
118.7(6) 121.7(3)
116.5(5) 114.5(3)
124.7(5) 123.8(3)
C1-C2
C2-C3
C3-C4
C4-C5
C5-C6
1.452(9) 1.477(6) C3-C2-C1
1.417(9) 1.429(6) C4-C3-C2
1.435(9) 1.416(5) C5-C4-C3
1.432(8) 1.442(5) C6-C5-C4
1.433(8) 1.425(5) C4-C5-C15
Ru1-C2 2.229(5) 2.216(4) C6-C5-C15
Figure 4. Perspective view of compound 14. Most hydro-
gen atoms are omitted for clarity.
Ru1-C3 2.144(6) 2.163(4) C1-C2-Ru1 119.1(5) 118.1(3)
Ru1-C4 2.203(5) 2.176(4) C15-C5-Ru1 131.2(4) 131.2(3)
Ru1-C5 2.213(6) 2.203(4) C9-C6-Ru1 124.3(4) 121.9(3)
Ru1-C6 2.255(5) 2.238(4) C4-C3-C7
117.9(4)
123.3(3)
128.6(3)
120.2(4)
114.4(4)
with previous observations.28,29 The CHO and COMe
groups in the acyclic ligands of complexes 6, 13, 14, and
17 display a typical CdO bond length between 1.214(9)
and 1.222(5) Å, along with significant shortening of the
C1-C2 bond [1.452(9),1.477(6) Å] compared to 1.521-
(5), 1.509(5), or 1.530(5) Å for C3-C7 of compounds 13,
14, and 17, respectively.
Dihedral angles formed by least-squared planes with
acyclic substituted pentadienyl ligands have reasonable
planar structures with maximum deviations for the
metal-bound atoms of 3.11°, 2.77°, 1.64°, 3.13°, and 1.90°
for compounds 6, 13, 14, 17, and 18, respectively. It is
interesting to observe that while most steric demand is
presented by methyl or phenyl substituents in the
acyclic ligand, less deviation of the planarity was found
for compounds 6 and 13 and compounds 13 and 14, as
well for Cp*Ru[1-5-η-anti-CH(COOMe)C(COOMe)CHC-
C1-C8
C3-C7
C5-C15
C6-C9
1.505(6) C2-C3-C7
1.521(5) C7-C3-Ru1
1.507(5) O1-C1-C8
1.482(7) 1.491(5) C2-C1-C8
All these compounds, except 9, have shown that
highly modified pentadienyl ligands can be obtained
(vide supra). The structural parameters for 6, 13, 14,
and 17 correspond, in general, fairly closely to each
other. In fact, the Ru-C6 bond distance in 14 is that
which sticks out, and it is longer (2.272(4) Å) than those
of 6, 13, or 17 (e.g., Ru-C6 ) 2.255(5), 2.238(4), and
2.216(3) Å, respectively). This may reflect a greater
steric problem in accommodating the phenyl ligands, as
opposed to either a single coupling product in 6 and 13
or the DMAD ligand in 17. Each complex contains an
η5-pentadienyl ligand, coordination preferentially being
observed through carbon atoms rather than through an
oxopentadienyl ligand which should have an oxygen
atom in the delocalized fragment. This is expected on
the basis of the soft nature of Ru(II), and it is consistent
(29) (a) Benyunes, S. A.; Day, J. P.; Green, M.; Al-Saadoon, A. W.;
Waring, T. L. Angew. Chem., Intl. Ed. Engl. 1990, 29, 1416. (b)
Trakarnpruk, W. Ph.D. Thesis, University of Utah, 1993.

Coupling Reactions in Half-Open Ruthenocenes(II)
Organometallics, Vol. 24, No. 12, 2005 2885
Table 8. Selected Bond Lengths (Å) and Bond
Angles (deg) for Compounds 14 and 17
bond lengths
14 17
bond angles
14 17
C1-O1
C1-C2
C2-C3
C3-C4
C4-C5
C5-C6
C1-C8
C3-C7
1.230(5) 1.224(4) O1-C1-C2
1.476(5) 1.460(5) C3-C2-C1
1.442(5) 1.434(5) C4-C3-C2
1.421(5) 1.421(5) C5-C4-C3
1.435(5) 1.436(5) C6-C5-C4
1.423(5) 1.433(5) O1-C1-C8
1.507(6) 1.505(5) C2-C1-C8
1.509(5) 1.530(5) C4-C3-C7
124.5(4) 125.1(4)
123.9(3) 126.6(3)
120.5(3) 119.4(3)
128.5(4) 125.9(3)
122.4(3) 124.5(3)
119.3(4) 119.6(4)
116.2(3) 115.3(4)
116.3(4) 117.3(3)
123.1(4) 123.4(3)
124.9(3) 119.1(3)
Ru1-C2 2.236(3) 2.223(3) C2-C3-C7
Ru1-C3 2.164(3) 2.161(3) C5-C6-C9
Ru1-C4 2.182(4) 2.184(3) C1-C2-Ru1 119.3(2) 116.3(2)
Ru1-C5 2.207(3) 2.148(3) C7-C3-Ru1 128.5(2) 126.9(2)
Ru1-C6 2.272(4) 2.216(3) C9-C6-Ru1 124.8(2) 117.6(2)
C5-C15 1.497(5)
C7-C31 1.520(5)
C31-C32 1.336(5)
C31-C33 1.487(5)
C5-C11
C6-C5-C11
C3-C7-C23
122.5(3)
109.9(3)
C4-C5-C15 114.4(3)
C3-C7-C31 113.8(3)
1.514(5) C6-C5-C15 123.2(3)
1.198(4) C15-C5-Ru1 130.7(2)
1.331(4) C7-C31-C32 121.3(3)
1.440(5)
Figure 5. Perspective view of compound 17. Most hydro-
gen atoms are omitted for clarity.
C11-O4
C11-O5
C12-O5
Table 9. Bond Distances (Å) and Angles (deg) for
Compound 18
bond lengths
bond angles
C1-C2
C2-C3
C3-C4
C4-C5
C5-C6
C6-C7
C7-C8
C8-C9
C4-C9
C8-C11
C6-O1
Ru1-C1
Ru1-C2
Ru1-C3
Ru1-C4
Ru1-C5
1.419(5)
1.417(5)
1.426(5)
1.432(4)
1.453(5)
1.515(5)
1.524(5)
1.532(5)
1.523(5)
1.531(4)
1.234(3)
2.181(3)
2.181(3)
2.203(3)
2.188(3)
2.221(3)
Ru1-C1-C2
C3-C2-C1
C4-C3-C2
C5-C4-C3
C6-C5-C4
C5-C4-C9
C3-C4-C9
O1-C6-C5
C5-C6-C7
C6-C7-C8
C7-C8-C11
71.01(18)
122.6(3)
127.0(3)
121.8(3)
119.3(3)
121.4(3)
116.8(3)
122.5(3)
117.8(3)
112.7(3)
110.7(3)
Figure 6. Perspective view of compound 18. Most hydro-
gen atoms omitted for clarity.
Table 7. Selected Bond Lengths (Å) and Angles
(deg) for Compound 9
distances from both ligands to the ruthenium atom in
the highly substituted complexes. The centroid Cp*-
Ru distance of compound 6 is particularly long (1.899
Å) compared with those of the more substituted com-
plexes 13, 14, 17, and 18, which are 1.851, 1.854, 1.851,
and 1.839 Å, respectively; meanwhile the similarity of
pentadienyl-Ru centroid distances is evident (1.653,
1.640, 1.648, 1.625, and 1.635 Å for compounds 6, 13,
14, 17, and 18, respectively). Compound 18 can be
comparedtoCp*Ru[2-methyl-4,5-(dimethylbicyclo[3.1.1]-
heptane)1-5-η-pentadienyl]19 (vide supra); in general
terms, it is observed that the pentadienyl fragment of
18 is more symmetric than the chiral molecule just
mentioned [Ru-Ccentral ) 2.203(3) vs 2.159(13)19 Å; C2-
C3 ) 1.417(5) and C12-C13 ) 1.355(15) Å19].
bond lengths
bond angles
C1-C2
C2-C3
C3-C4
C4-O1
C4-C5
C5-C6
C6-C7
C1-C6
C1-C19
C18-C19
1.520(8)
1.409(8)
1.452(8)
1.226(7)
1.566(8)
1.515(9)
1.536(9)
1.545(8)
1.565(8)
1.526(7)
C2-C1-C6
C2-C1-C19
C6-C1-C19
C3-C2-C1
C3-C2-Ru1
C1-C2-Ru1
C2-C3-C4
C2-C3-Ru1
C4-C3-Ru1
O1-C4-C3
108.4(5)
113.2(5)
111.4(5)
118.9(5)
74.7(4)
117.6(4)
121.2(6)
67.2(3)
129.0(4)
123.5(6)
(CMe3)CH(COCMe3)].27 This is not the case for the
dimethyl acetylenedicarboxylate double-coupling de-
rivative 17. Although the Ru-C distances for the Cp*
and pentadienyl ligands of 6, 13, 14, 17, and 18 are
rather similar, the metal atom is located closer to the
acyclic group, 1.859 and 1.648 Å (average values for Cp*
and pentadienyl distances, respectively), which is ex-
pected according to the wider acyclic pentadienyl ligand.22
The difference of the average values ∆ ) 0.211 is even
shorter than that corresponding to half-open rutheno-
cenes Cp*Ru(3-methyl-η5-pentadienyl) (1.567 vs 1.834
Å; ∆ ) 0.267)22 and Cp*Ru(2,4-dimethyl-η5-pentadienyl)
(1.611 vs 1.836 Å; ∆ ) 0.225),30 which reflects the longer
The single crystal of Cp*Ru[1-5-η-syn-CH(COOMe)C-
(COOMe)CHC(Me)CH(COMe)] (16) showed two mol-
ecules in the unit cell. However, the high disorder
observed led to a poor-quality structure, which was also
observed for compound 15.
Conclusions
A successful synthesis of Cp*Ru(η5-CH2CHCHCHO)
was achieved. Several types of substituted pentadienyl
ruthenium complexes can be obtained by coupling
reactions of oxodienyl ligands with diphenylacetylene
(30) Ramirez-Monroy, A.; Sa´nchez-Castro, M. E.; Cervantes Va´s-
quez, M.; Aleman Figueroa, I. R.; Paz-Sandoval, M. A. Unpublished
results.

2886 Organometallics, Vol. 24, No. 12, 2005
Sa´nchez-Castro et al.
(Cp*RuCl2)2 (2.1 mmol) at room temperature was added, drop
by drop, a solution of CH2CHCHCHOSiMe3 (0.37 mL, 2.1
mmol) in THF (2 mL). The dark brown solution turned yellow-
brown after 1 h, and the stirring was continued for 1.5 h. After
filtration and evaporation of the solvent, the residue was
washed with hexane (60 mL) and filtered, and the volume was
reduced until 10 mL, precipitating bright orange needles of
compound 2 at -15 °C with mp 103-105 °C in 40% yield34
(350 mg, 0.85 mmol). The mustard-yellow solid, insoluble in
hexane, was purified on a preparative silica gel plate, using
acetone. The eluent was a mixture of ethyl acetate/acetone (8:
2). The orange band was removed and extracted with acetone
from the silica. Recrystallization with chloroform and hexane
afforded orange-red crystals of 3, which do not melt and
decompose above 200 °C, in 56% yield (442 mg, 1.18 mmol).
Compound 2: Anal. Calcd for C17H29ClOSiRu: C, 49.33; H,
7.01, Si, 6.77. Found: C, 49.53; H, 7.02; Si, 7.02. IR (KBr,
cm-1): 2956 (m), 2910 (m), 1654 (m, br), 1250 (s), 1170 (vs),
872 (vs), 848 (s). LR FAB MS (matrix: 3-NBA/Li): m/z 414
(40) [M+], 379 (100), 364 (88). Compound 3: Anal. Calcd for
C14H20Cl2ORu: C, 44.68; H, 5.30. Found: C, 44.52; H, 5.37.
IR (KBr, cm-1): 2968 (m), 2915 (m), 2861 (m), 1691 (vs), 1479
(m). LR FAB MS (matrix: 3-NBA/Li): m/z 382 (70) [M+ + Li],
383 (100) [M+ + 1 + Li].
or dimethyl acetylenedicarboxylate. It was established
that the formation of the new compounds depends on
the presence of the oxygen heteroatom and the concen-
tration of the alkyne. The reactions always require an
excess of the alkyne, and it was found that the diphen-
ylacetylene is more selective compared to the dimethyl
acetylenedicarboxylate. A second molecule of alkyne can
react through the C-H activation of the methyl sub-
stituent in compound 4 to give even more substituted
pentadienyl ligands coordinated to the Cp*Ru fragment.
In contrast, the allyl derivative 5 affords evidence of
formation of a substituted cyclopentadienyl complex.
The diphenylacetylene derivatives are very stable,
whereas the dimethylacetylenedicarboxylate analogues
are less stable and can be easily hydrolyzed in solution.
The Cp*Ru(pentadienyl) class of compounds has proven
capable of supporting a rich variety of substituted
pentadienyl ligands, which include methyl, phenyl,
aldehyde, acetyl, and acetate groups, which will allow
a greater understanding of the electronic nature of the
pentadienyl ligands.
Synthesis of Cp*Ru[1-3-η-endo-syn-(Me)CHCHCH(O-
Et)]Cl2 (5). To a brown solution of EtOH (30 mL) containing
500 mg of (Cp*RuCl2)2 (1.6 mmol) at room temperature was
added, drop by drop, CH2CHCHCHOSiMe3 (0.57 mL, 3.2
mmol). The dark brown solution turned yellow-brown after 3.5
h under reflux. After filtration and evaporation of the solvent,
the dark orange residue was washed, six times, with toluene
(∼8 mL). The pale orange complex 5, insoluble in toluene, was
recrystallized at -15 °C with chloroform/hexane as orange
needles (317 mg, 0.78 mmol) with mp 169-171 °C in 48% yield.
Anal. Calcd for C16H26Cl2ORu: C, 47.29; H, 6.45. Found: C,
46.59; H, 6.49. IR (KBr, cm-1): 2982 (m), 2908 (m), 1538 (s),
1452 (m, br), 1380 (vs), 1217 (s), 1030 (s), 853 (m, br).
Synthesis of Cp*Ru[1-5-η-syn-CH(Ph)C(Ph)CHCHCH-
CHO] (6), Cp*Ru[1,4,5-η-C(Ph)C(Ph)CH2CHCH2](CO) (7),17
[Cp*Ru(1-3-exo-syn-η-CH2CHCHCHO)(η2-PhCtCPh)] (8-
exo),18 [Cp*Ru(1-3-endo-anti-η-CH2CHCHCHO)(η2-PhCt
CPh)] (8-endo), [Cp*Ru[1,6,7,10,11-η-CH(CH)4CCHC(Ph)-
CH(CH)2C(O)CH(C6H4)CH(Ph)](9),andCp*Ru[3-5-η-C(Ph)-
C(Ph)CHCHCHC(O)](η2-PhCHdCHPh) (10). (a) Reaction
of 1 with Diphenylacetylene in a 1:2 Ratio. A yellow
solution of 1 (150 mg, 0.49 mmol) in 30 mL of THF was under
reflux, for 24 h, with 17.5 mg (0.98 mmol) of diphenylacetylene,
giving a dark brown solution, which was filtered and evapo-
rated under vacuum. Extractions with Et2O, followed by
reducing the volume to 2 mL, and adding this sample in a
chromatographic column (neutral alumina, 19 × 2 cm) afforded
three different fractions. The first band, eluted with hexane,
was diphenylacetylene along with compound 7. After a second
chromatography of this mixture, with hexane and hexane/
diethyl ether, respectively, the diphenylacetylene and com-
pound 7 were obtained pure. 7 precipitated at -15 °C as an
orange powder, in very low yield, 1.2% (3 mg, 0.006 mmol).
The second band gave, after treatment with hexane/diethyl
ether (1:1), compound 6 as a yellow solid at -78 °C in 35%
yield (83.1 mg, 0.17 mmol). With the same mixture of solvents,
yellow needles (mp 214-216 °C) were obtained from recrys-
tallization at room temperature. The third band, using diethyl
ether as eluant, afforded compound 8-endo as yellow needles
with mp 135-138 °C in 12% yield (28 mg, 0.058 mmol). Anal.
Calcd for 8-endo: C28H30ORu: C, 69.54; H, 6.25. Found: C,
69.21; H, 6.06. IR (KBr, cm-1): 3067 (w), 2911 (w), 2858 (w),
1844 (m), 1637 (vs), 1591 (w), 1484 (m), 1025 (m), 756 (m),
692 (m). MS: 483 (80) [M+], 454 (100), 314 (26), 236 (26).
Experimental Section
Standard inert-atmosphere techniques were used for all
syntheses and sample manipulations. The solvents were dried
by standard methods (hexane and pentane with CaH2, diethyl
ether and THF with Na/benzophenone, CH2Cl2 and CHCl3 with
CaCl2, benzene and toluene with Na) and distilled under argon
prior to use. Compounds (Cp*RuCl)4,31 (Cp*RuCl2)2,32 Cp*Ru-
(2,4-dimethyl-η5-oxopentadienyl),22,28 and Cp*Ru(2,4-dimethyl-
η5-pentadienyl),22,28 were prepared according to literature
procedures. All other chemicals, such as RuCl3‚nH2O, zinc
activated,33 1-(trimethylsilyloxi)buta-1,3-diene, diphenylacety-
lene, and dimethyl acetylenedicarboxylate, were used as
purchased from Strem Chemicals, Fluka, and Sigma-Aldrich.
Elemental analyses were performed at the Chemistry Depart-
ment of Cinvestav with a Thermo-Finnigan Flash 112 and
Desert Analytics, Tucson, AZ. IR spectra were recorded on a
Perkin-Elmer 6FPC-FT spectrophotometer using KBr or CHCl3.
1H and 13C NMR spectra were recorded on JEOL GSX-270,
JEOL Eclipse-400 MHz, or Bruker DPX 300 MHz spectrom-
eters in deoxygenated, deuterated solvents. NMR chemical
shifts are reported relative to TMS. Mass spectra were
obtained with a Hewlett-Packard HP-5990A. Ionization was
by FAB with xenon atoms at 6 keV energy (Washington
University, St. Louis, MO); m/z values are given relative to
102Ru. Melting points were determined using a Mel-Temp
apparatus and are not corrected.
Synthesis of Cp*Ru(η5-CH2CHCHCHO) (1). An orange-
yellow diethyl ether/hexane (1:1) solution (2 mL) containing
200 mg of 2 (0.48 mmol) was passed through chromatographic
column on neutral deactivated alumina (Brockmann I) (2.5 ×
18 cm) with elution by hexane and diethyl ether. The yellow
solution was evaporated and recrystallized in pentane at -15
°C, giving after 24 h canary-yellow needles with mp 92-93
°C in 67% yield (98.8 mg, 0.32 mmol). Anal. Calcd for C14H20-
ORu: C, 55.05; H, 6.60. Found: C, 54.94; H, 6.51. IR (KBr,
cm-1): 2951 (s), 2901 (vs), 1472 (s), 1377 (vs), 1266 (vs). MS
(20 eV): m/z 306 (64) [M+], 278 (100), 236 (88).
Synthesis of Cp*Ru(1-4-η-CH2CHCHCHOSiMe3)Cl (2)
and Cp*Ru(1-3-η-endo-syn-CH2CHCHCHO)Cl2 (3). To a
red-brown solution of THF (25 mL) containing 650 mg of
(31) Fagan, P. J.; Ward, M. D.; Calabrese J. C. J. Am. Chem. Soc.
1989, 111, 1698.
(32) (a) Oshima, N.; Suzuki, H.; Moro-Oka, Y. Chem. Lett. 1984,
1161. (b) Tilley, T. D.; Grubbs, R. H.; Bercaw, J. E. Organometallics
1984, 3, 274.
(34) Compound 2 could be obtained in better yield (88%) from
[Cp*RuCl]4, without formation of compound 3.
(33) Yamamura, S.; Hirata, Y. J. Chem. Soc. (C) 1968, 2887.

Coupling Reactions in Half-Open Ruthenocenes(II)
Organometallics, Vol. 24, No. 12, 2005 2887
(b) Reaction of 1 with Diphenylacetylene in a 1:3.5
Ratio. The reaction was carried out via a procedure similar
to that previously described in (a). From this reaction four
different fractions were obtained from the chromatography
column. The first band afforded compound 7 along with
diphenylacetylene. The second band yielded 6, 8-exo, and
diphenylacetylene, while the third and fourth bands were
eluted with diethyl ether, giving compounds 8-endo and 10,
respectively. The recrystallization with the minimum amount
of diethyl ether of the second fraction of the chromatography
afforded, after 3 days at room temperature, yellow (6; 71 mg,
014 mmol, 30%) and orange (9; few crystals) needles, which
were separated manually. Compound 8-endo was recrystal-
lized in diethyl ether and obtained as yellow needles in 2%
yield (5 mg, 0.01 mmol). Finally, the oily yellow compound 10
was again chromatographed with diethyl ether, giving after
evaporation of the solvent and recrystallization with pentane
at -78 °C traces of a red-brown solid with a mp 142-145 °C
in ∼3% yield (10 mg, 0.15 mmol).
The last yellow band eluted with diethyl ether was compound
15 along with 18. After a second preparative alumina plate,
using a mixture of hexane/diethyl ether (6:4) compounds 15
and 18 were separated. Evaporation and recrystallization from
hexane/diethyl ether at -15 °C gave the amber compound 15,
mp 203-205 °C, in low yield, and compound 18 was obtained
from diethyl ether at -15 °C as a few yellow single crystals.
Compound 13: Anal. Calcd for C30H34ORu: C, 70.42; H, 6.70.
Found: C, 70.31; H, 6.90. IR (KBr, cm-1): 3066 (w), 2961 (s),
2905 (s), 1660 (vs), 1596 (m). MS: m/z (70 eV) 512(12) [M+],
495(100), 469(90), 453(16), 439(12), 415(5), 377(2), 327(3), 236-
(7), 233(22), 178(4), 91(5), 43(73). Compound 15: Anal. Calcd
for C30H34ORu: C, 70.42; H, 6.70. Found: C, 70.15; H, 6.80.
IR (KBr, cm-1): 3057 (w), 2964 (s), 2905 (s), 1639 (vs), 1596
(m). MS: m/z (70 eV) 512(13) [M+], 495(100), 469(78), 453-
(12), 439(9), 415(4), 377(1), 314(2), 236(4), 43(2).
(b) Reaction of 4 with Diphenylacetylene in a 1:3
Ratio. A solution of 4 (200 mg, 0.60 mmol) in 25 mL of benzene
at room temperature was stirred. Then, diphenylacetylene (321
mg, 1.8 mmol) was added and the mixture was refluxed for
21 h. The solution was evaporated under vacuum, and the
residue was chromatographed on deactivated neutral alu-
mina.20 The use of hexane as eluant allows removal of the
excess diphenylacetylene, and compound 13 was then collected
from the column (20 × 1.5 cm) with a mixture of hexane/diethyl
ether (8:2) as the eluant. A yellow band was collected. The
solvent was reduced and the product crystallized from diethyl
ether at room temperature to give 262 mg (0.51 mmol, 85.4%)
of 13 as a yellow crystalline powder. Compound 14 was
obtained in traces (see text) as a yellow powder with a melting
point of 235-238 °C (dec). Compound 14: Anal. Calcd for
C44H44ORu: C, 76.60; H, 6.43. Found: C, 77.23; H, 6.45. MS:
m/z 690(5) [M+], 673(100), 667(14), 647(20), 556(6), 497(10),
454(46), 436(14), 429(10), 415(18), 363(6), 338(9), 261(9), 243-
(9) 236(5), 193(4), 44(5).
Synthesis of Isomers Cp*Ru[1-5-η-syn-CH(Ph)C(Ph)-
CHCHCH(CHO)] (6 and 11). (a) To a stirred solution of
compound 3 (60 mg, 0.16 mmol) in THF (30 mL) were added
diphenylacetylene (14.22 mg, 0.79 mmol) and powdered zinc
(0.1 g, 1.52 mmol). The mixture was refluxed and stirred for 5
h. During this time the reaction goes from red-orange to
yellow-orange. Filtration of the reaction and evaporation of
the THF gave an orange residue, which was washed with
diethyl ether (10 mL), the volume was reduced under vacuum,
and at -5 °C orange needles of 11 were obtained in very low
yield. Mp: 182-185 °C. The insoluble fraction was dissolved
in dichloromethane, and after chromatography on neutral
alumina (2 × 15 cm) and using diethyl ether as eluant, 6 was
obtained in 15% yield (11.5 mg, 0.023 mmol).
(b) The reaction was carried out as described in (a), but the
reflux was prolonged for 10 h, affording 6 in 20% yield (15.4
mg, 0.032). Compound 6: Anal. Calcd for C28H30ORu: C, 69.54;
H, 6.25. Found: C, 69.41; H, 6.12. IR (CHCl3, cm-1): 3055 (w),
2899 (w), 2802 (w), 1666 (vs), 1595 (m), 1461 (m, br), 1135
(m). MS: m/z 483 (13) [M+], 236 (47).
(c) Interconversion of Compound 13 into Isomer 15.
A stirred solution of 13 (50 mg, 0.098 mmol) and 1.5 g of
alumina (Brockmann I) in 25 mL of toluene was refluxed for
6.5 h. The solution was filtered and the alumina washed with
acetone. The solvent was evaporated under vacuum, and the
Identification of Cp*Ru[1-5-η-C(Ph)C(Ph)C(Me)CHCH]
(12). To a stirred solution of compound 5 (80 mg, 0.20 mmol)
in THF (20 mL) were added diphenylacetylene (0.17 g, 0.95
mmol) and powdered zinc (64 mg, 0.98 mmol). The mixture
was refluxed and stirred for 1 h. During this time the reaction
goes from deep orange to dark brown. After stirring 8 h the
solution is yellow-brown. Filtration of the reaction and evapo-
ration of the THF gave an orange residue, which was washed
three times (5 mL) with diethyl ether/hexane (1:1), the volume
was reduced under vacuum, and the reaction mixture was
treated by column chromatography in neutral alumina (2 ×
20 cm). Three fractions were collected, but only the first one
was interesting, showing a mixture of diphenylacetylene and
compound 12. An attempt to purify 12 in a second chroma-
tography, using hexane as eluant, was unsuccessful due to the
similar solubilities of both compounds. Characterization of 12
1
residue (product distribution was determined by H NMR in
a ratio 2.8:2.5:4.7 for 13, 15, and unknown compound, respec-
tively) was chromatographed on neutral alumina (Brockmann
I) eluted with pentane/diethyl ether (1:1). The first fraction
gave a mixture of 13 along with the major unknown compound
1
[δ, H NMR (C6D6): 1.38 (s, 15H), 1.54 (s, 3H), 2.52 (s, 3H),
0.96 (s, 1H), 4.92 (s, 1H), 5.92 (s, 1H), 6.20 (d, J ) 7.67 Hz,
1H), 6.98, 7.12, and 7.39 (Ar-H)]. A second yellow band was
collected, giving after evaporation compound 15 as yellow
powder.
Synthesis of Cp*Ru[1-5-η-syn-CH(COOMe)C(COOMe)-
CHC(Me)CH(COMe)] (16) and Cp*Ru[1-5-η-syn-CH-
(COOMe)C(COOMe)CHC{CH2C(COOMe)CH(COOMe)}-
CH(COMe)] (17). A solution of 4 (200 mg, 0.60 mmol) in 25
mL of benzene at room temperature was stirred. Then,
dimethyl acetylendicarboxylate (0.22 mL, 1.8 mmol) was added
and the mixture was refluxed for 22 h. The solution was
evaporated under vacuum, and the residue was chromato-
graphed on neutral alumina (Brockmann I). The first fraction
collected with a mixture of hexane/diethyl ether (2:8) gave,
after evaporation and recrystallization in diethyl ether, the
amber compound 16, which has a mp 178-180 °C, in 13% yield
(37.0 mg, 0.08 mmol). A second yellow band was collected from
diethyl ether, giving, after evaporation and recrystallization
from hexane/diethyl ether at -78 °C, compound 17 as yellow
needles with mp 128-130 °C in 30% yield (111.1 mg, 0.18
mmol). Anal. Calcd for 16, C22H30O5Ru: C, 55.57; H, 6.36.
Found: C, 55.82; H, 6.69. IR (KBr, cm-1): 3071 (w), 2954 (s),
2908 (s), 1728 (vs), 1705 (vs), 1663 (vs), 1439 (vs, br). MS: m/z
476(17) [M+], 459(100), 431(4), 401(22), 385(6), 373(15), 264-
(25), 236(72), 179(33), 149(11), 105(8), 91(15), 77(15), 59(15),
1
was carried out exclusively through H and 13C NMR.
Synthesis of the Isomers Cp*Ru[1-5-η-CH(Ph)C(Ph)-
CHC(Me)CH(COMe)] (13 and 15) and Compounds Cp*Ru-
[1-5-η-syn-CH(Ph)C(Ph)CHC{CH2C(Ph)CH(Ph)}CH-
(COMe)] (14) and Cp*Ru[1-5-η-CH2C(Me)CHC{CH2-
C(Me)2CH2CO}CH] (18). (a) Reaction of 4 with Diphen-
ylacetylene in a 1:1 Ratio. A solution of 4 (248 mg, 0.74
mmol) in 25 mL of benzene at room temperature was stirred,
diphenylacetylene (133 mg, 0.74 mmol) was added, and the
mixture was refluxed for 33.5 h. The solution was evaporated
under vacuum, and the residue was chromatographed on
neutral alumina (Brockmann I). The first fraction collected
with a mixture of hexane/diethyl ether (8:2) gave after
evaporation compound 13 as yellow needles with mp 176-178
°C in 40% yield (152.2 mg, 0.30 mmol). A second band was
collected with hexane/diethyl ether (5:5) to give compound 4.

2888 Organometallics, Vol. 24, No. 12, 2005
Sa´nchez-Castro et al.
43(94). Anal. Calcd for 17, C28H36O9Ru + EtOEt: C, 55.56; H,
6.70. Found: C, 55.53, H, 6.31. IR (KBr, cm-1): 3431 (w, br),
2987 (w), 2953 (s), 2910 (s), 1717 (vs, br), 1651 (vs), 1438 (vs,
br). MS: m/z 618(12) [M+], 601(86), 587(4), 543(13), 527(4),
515(4), 485(4), 455(4), 429(6), 397(3), 339(3), 289(5), 264(18),
236(61), 203(9), 43(100).
X-ray Structure Determination of Compounds 6, 9, 13,
14, 17, and 18. Single crystals of compounds 6, 9, 13, 14, 17,
and 18 were mounted on glass fibers. X-ray data were collected
on Enraf Nonius Kappa CCD or CAD4 difractometers, using
graphite-monochromated Mo KR radiation (λ ) 0.71073 Å) at
low temperature. Structure solution and refinement were
carried out using SHELXS-9735 included in the package
Wingx.36 The ruthenium positions were determined by the
Patterson method. The remaining non-hydrogen atoms were
found by successive full-matrix least-squares refinement and
difference Fourier map calculations. In general, non-hydrogen
atoms were refined anisotropically, while hydrogen atoms were
placed at idealized positions. Absorption correction was applied
for all compounds. Data collection parameters and structure
refinement details are summarized in Table 5. Compound 9
has a disorder molecule of diethyl ether, which is not included
in the crystallographic data.
Acknowledgment. Financial support for this work
was provided by Conacyt, Mexico (38507-E). M.E.S.C.
and A.R.M. thank Conacyt for scholarships. We express
our thanks to Dr. Angelina Flores Parra for helpful
discussions and one of the referees for helpful comments
and a better view of Figure 3. We thank the service of
the Washington University Mass Spectrometer Re-
source, which is supported by the NIH Center for
Research Resources. We thank Ma. Luisa Rodr´ıguez for
assistance with some NMR experiments.
Supporting Information Available: Tables of data of
atomic coordinates, bond lengths and angles, anisotropic
thermal parameters, and least-squares planes for compounds
6, 9, 13, 14, 17, and 18 are given, and data for these
compounds are also given in CIF format. This material is
available free of charge via the Internet at http://pubs.acs.org.
(35) Sheldrick, G. M. SHELXL, Program for Crystal Structure
Refinement; University of Go¨ttingen: Goo¨ttingen, Germany, 1998.
(36) Farrugia, L. J. J. Appl. Crystallogr. 1999, 32, 837
OM050018O