Intramolecular allylation of a Ru-Cp* methyl group

Article abstract of DOI:10.1021/om701248d

The salts [Ru(Cp*)(CH₃CN)(N,N)](PF₆), 6 (N,N = bipyridine, 4,4′-dimethylbipyridine, and phenanthroline), react with allyl carbonates to afford new complexes that contain tethered ligands derived from deprotonation of one Cp* methyl group. The new Ru tetrametiryl Cp complexes contain a CH₂-CHRCH=CH₂ fragment (R = H or Ph), which coordinates to the metal via the double bond. The salts 6 isomerize the branched carbonate PhCH(OCO₂Bu^t)CH=CH₂ to the linear isomer.

Full text of DOI:10.1021/om701248d

Organometallics 2008, 27, 1591–1595
1591
Intramolecular Allylation of a Ru-Cp* Methyl Group
Helen Caldwell and Paul S. Pregosin*
Laboratory of Inorganic Chemistry ETHZ Hönggerberg 8093 Zürich, Switzerland
ReceiVed December 14, 2007
The salts [Ru(Cp*)(CH3CN)(N,N)](PF6), 6 (N,N ) bipyridine, 4,4′-dimethylbipyridine, and phenan-
throline), react with allyl carbonates to afford new complexes that contain tethered ligands derived from
deprotonation of one Cp* methyl group. The new Ru tetramethyl Cp complexes contain a CH2-
CHRCHdCH2 fragment (R ) H or Ph), which coordinates to the metal via the double bond. The salts
6 isomerize the branched carbonate PhCH(OCO2But)CHdCH2 to the linear isomer.
Introduction
An increasingly large number of ruthenium complexes are
finding applications in homogeneous catalysis.1–3 Among the
most popular Ru derivatives are those containing Cp or Cp*
ligands.4 Although complexes of Ru(II) are still the most
prevalent, there is an increasing interest in the use of Ru(IV)
salts as starting materials for selected catalytic transformations.5
Apart from catalytic allylation with Pd and other transition
metal catalysts, one finds a number of reports on Ru-catalyzed
reactions4–7 (see eq 1).
Ruthenium allylation catalysts can be regioselective and afford
high branched-to-linear ratios in the products.4–6 A number of
catalysts are known, and 1-5 represent typical examples. In
some cases, for example, using 4 and 5, the catalysis has been
found to be relatively slow.4 There is no immediately obvious
reason for this, since oxidative addition of the branched
compound PhCH(X)CHdCH2, X ) a suitable halogen or
carbonate leaving group, starting from Trost’s catalyst,8
[Ru(CH3CN)3(Cp*)](PF6), 1, is complete within several minutes
at room temperature and affords high yields of isolable Ru(IV)
allyl complexes.9 We show here that chelating nitrogen salts
[Ru(CH3CN)(N,N)](PF6), 6, can (a) isomerize the branched allyl
starting material and (b) produce new unexpected Ru(II) tethered
complexes derived from allyl carbonates.
* Corresponding author. E-mail: pregosin@inorg.chem.ethz.ch.
(1) (a) Grubbs, R. H. AdV. Synth. Catal. 2007, 349, 23–24. (b) Grubbs,
R. H Tetrahedron 2004, 60, 7117–7140.
(2) (a) Rigaut, S.; Massue, J.; Touchard, D.; Fillaut, J. L.; Golhen, S.;
Dixneuf, P. H. Angew. Chem., Int. Ed. 2002, 41, 4513. (b) Rigaut, S.;
Perruchon, J.; Guesmi, S.; Fave, C.; Touchard, D.; Dixneuf, P. H. Eur.
J. Inorg. Chem. 2005, 44, 7–460. (c) Bustelo, E.; Dixneuf, P. H. AdV. Synth.
Catal. 2005, 347, 393–397. (d) Bruneau, C.; Dixneuf, P. H. Angew. Chem.,
Int. Ed. 2006, 45, 2176–2203.
Results and Discussion
The chelating nitrogen complexes were prepared according
to the literature.4,7 These cationic complexes [Ru(Cp*)(CH3-
CN)(N,N)](PF6), 6, which contain bipyridine and phenanthroline
(3) Trost, B. M.; Rudd, M. T. Org. Lett. 2003, 5, 1467–1470. (a) Trost,
B. M.; Rudd, M. T. J. Am. Chem. Soc. 2005, 127, 4763–4776. (b) Trost,
B. M.; Pinkerton, A. B.; Seidel, M. J. Am. Chem. Soc. 2001, 123, 12466–
12476. (c) Trost, B. M.; Rudd, M. T. J. Am. Chem. Soc. 2001, 123, 8862–
8863. (d) Trost, B. M.; Toste, F. D.; Shen, H. J. Am. Chem. Soc. 2000,
122, 2379–2380.
(7) (a) Mbaye, M. D.; Demerseman, B.; Renaud, J. L.; Toupet, L.;
Bruneau, C. Angew. Chem., Int. Ed. 2003, 42, 5066–5068. (b) Renaud, J. L.;
Bruneau, C.; Demerseman, B. Synlett 2003, 40, 8–410. (c) Mbaye, M. D.;
Renaud, J. L.; Demerseman, B.; Bruneau, C. Chem. Commun. 2004, 187,
0–1871. (d) Mbaye, M. D.; Demerseman, B.; Renaud, J. L.; Toupet, L.;
Bruneau, C. AdV. Synth. Catal. 2004, 346, 835–841. (e) Jerphagnon, T.;
Renaud, J. L.; Bruneau, C. Tetrahedron: Asymmetry 2004, 15, 2101–2111.
(f) Gurbuz, N.; Ozdemir, I.; Cetinkaya, B.; Renaud, J. L.; Demerseman,
B.; Bruneau, C. Tetrahedron Lett. 2006, 47, 535–538. (g) Renaud, J. L.;
Demerseman, B.; Mbaye, M. D.; Bruneau, C. Curr. Org. Chem. 2006, 10,
115–133.
(4) Bruneau, C.; Renaud, J. L.; Demerseman, B. Chem.-Eur. J. 2006,
12, 5178–5187.
(5) (a) Fernandez, I.; Hermatschweiler, R.; Breher, F.; Pregosin, P. S.;
Veiros, L. F.; Calhorda, M. J. Angew. Chem., Int. Ed. 2006, 45, 1–6. (b)
Fernandez, I.; Schott, D.; Gruber, S.; Pregosin, P. S. HelV. Chim. Acta 2007,
90, 271–276. (c) Zaitsev, A. B.; Gruber, S.; Pregosin, P. S. Chem Commun.
2007, 469, 2–4693. (d) Tanaka, S.; Saburi, H.; Kitamura, M. AdV. Synth.
Catal. 2006, 348, 375–378. (e) Cadierno, V.; Crochet, P.; García-Garrido,
S. E.; Gimeno, J. Curr. Org. Chem 2006, 10, 165–183. (f) Cadierno, V.;
García-Garrido, S. E.; Gimeno, J. Chem. Commun. 2004, 232–233. (g)
Cadierno, V.; García-Garrido, S. E.; Gimeno; Varela-Álvarez, A.; Sordo,
J. A. J. Am. Chem. Soc. 2006, 128, 1360–1370. (h) Cadierno, V.; Gimeno,
J.; Nebra, N. Chem.-Eur. J. 2007, 13, 6590–6594.
(8) Trost, B. M.; Older, C. M. Organometallics 2002, 21, 2544–2546.
(9) (a) Hermatschweiler, R.; Fernandez, I.; Breher, F.; Pregosin, P. S.;
Veiros, L. F.; Calhorda, M. J. Angew. Chem., Int. Ed. 2005, 44, 4397–
4400. (b) Hermatschweiler, R.; Fernandez, I.; Pregosin, P. S.; Watson, E. J.;
Albinati, A.; Rizzato, S.; Veiros, L. F.; Calhorda, M. J. Organometallics
2005, 24, 1809–1812.
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10.1021/om701248d CCC: $40.75
2008 American Chemical Society
Publication on Web 03/14/2008

1592 Organometallics, Vol. 27, No. 7, 2008
Caldwell and Pregosin
Scheme 1
methyl groups of the complexed Cp* ligand (see Figure 1). A
series of two-dimensional proton and carbon correlation spectra
allowed the assignment of six nonequivalent protons attached
to two methine and two methylene carbons, all at relatively low
frequency (in addition to the phenyl and nitrogen ligand signals).
The complexed olefin 13C data for 7a are fairly typical12–14 and
reveal the CH2 and CH-olefinic carbons at 52.0 and 87.0 ppm,
ligands (see Scheme 1), were then allowed to react with 1 equiv
of the branched carbonate PhCH(OCO2But)CHdCH2 in an
NMR tube. To our surprise, we found that the branched
respectively. These results, combined with NOE, mass spectral,
and microanalytical data, strongly support the structures indi-
(2)
carbonate isomerizes in ca. 30 min to the linear carbonate, as
indicated in eq 2.10 Further, if one continues to monitor this
solution at ambient temperature, salt 6a requires 4 h to afford
20% of a new species (which we will show has structure 7).
Although salt 6b manages the same 20% conversion in ca. 50
min, this is still a relatively slow reaction. If one starts from
the linear carbonate, the chemistry is even slower. Using
PhCHdCHCH2Cl as reagent, instead of the carbonate, one
observes between 50% and 80% conversion to the known7a
Ru(IV) allyl cations [Ru(Cp*)(N,N)(η3-PhCHCHCH2)]+, after
ca. 20 min. While this reaction is faster, it does not go to
completion, perhaps because the Cl- set free reacts to afford a
less active complex. Although not shown in Scheme 1, we have
also prepared the biquinoline analogue of 6; however, we find
no reaction of this salt with either PhCHdCHCH2Cl or
PhCHdCHCH2(OCO2OBut) and presume that olefin complex-
ation may be hindered.
(3)
cated.15 Although Castro et al.12 have reported a related structure
using a dinuclear tetramethylfulvene as starting material (see eq
3), we believe this to be the first reported intramolecular allylation
reaction of a Cp* methyl group.
The relative position of the coordinated double bond, ap-
proximately parallel to the Cp moiety, was determined via 2-D
NOESY spectroscopy (see Figure 2). One finds selective cross-
peaks from (a) one of the two nonequivalent ortho pyridine
protons to the two CH2 protons at the unsubstituted end of the
In an effort to accelerate an otherwise very slow oxidative
addition step in the carbonate chemistry, 2 equiv of a carbonate
were allowed to react with 6 at 333 K in acetonitrile solution.
Rather than the expected Ru (IV) allyl salt, a new species, 7,
appeared; see Scheme 2.
Although the salts 7 could be prepared in good yield on a
small preparative scale, the correct structures were not im-
mediately obvious. On the basis of the absence of the relatively
complicated (but typical) multiplet for the central allyl 1H
resonance (which often appears between 5 and 7 ppm5,9,11), it
complexed double bond and (b) selective cross-peaks from the
second ortho pyridine proton to the aliphatic and olefinic CH
methine protons, as indicated by 8. Further, each of the two
(10) The branched and linear carbonates have been prepared separately
and their corresponding proton spectra are readily distinguishable. It is
known that oxidative addition of the branched isomer can be faster than
that for the linear isomer.
(11) Fernandez, I.; Pregosin, P. S.; Albinati, A.; Rizzato, S. Organo-
metallics 2006, 25, 4520–4529.
(12) Castro, A.; Turner, M. L.; Maitlis, P. M. J. Organomet. Chem. 2003,
674, 45–49.
(13) Faller, J. W.; Chase, K. J. Organometallics 1995, 14, 1592–1600.
(14) Koelle, U.; Kang, B.; Spaniol, T. P.; Englert, U. Oranometallics
1992, 11, 249–254.
(15) We have also allowed 6b to react with the branched naphthyl
carbonate C10H9CH(OCO2But)CHdCH2 (substituted at the 1-naphthyl
position). One observes ca 50% of the product of type 7; however this
could not be readily separated from a significant amount of side product.
was clear that 7 was not a routine Ru(IV) allyl salt. Both the
1H and 13C spectra revealed four nonequivalent Cp methyl
groups, instead of the usual sharp singlet for the equivalent five

Intramolecular Allylation of a Ru-Cp* Methyl Group
Organometallics, Vol. 27, No. 7, 2008 1593
Scheme 2
ortho pyridine protons shows selective cross-peaks to the two
proximate methyl groups of the (now) tetramethyl Cp ligand.
The position of the olefin in structure 8 is in agreement with
literature solid-state results for Ru(Cp-type) olefin complexes.12–14
A mechanistic rationalization for the appearance of the olefin
complexes 7 is given in Scheme 3 On warming the sample, the
oxidative addition takes place to afford a Ru(IV) allyl species. The
base set free in this step (either the carbonate or the alkoxide formed
when the carbonate decomposes) deprotonates one of the Cp*
methyl groups, thereby generating an internal anionic carbon
nucleophile. Attack of this carbon atom on the coordinated allyl
moiety affords the observed Ru(II) product. One can consider this
as Ru-based intramolecular allylic alkylation chemistry using allyl
carbonates. The observation of the branched product is consistent
with calculations9a that suggest an orbital-controlled product. While
“tucked-in” Cp* complexes,16–18 as well as a number of tethered
Cp derivatives,19–25 are well-known in the literature, this Ru-
mediated intramolecular allylation is unprecedented.
Summarizing, at elevated temperatures the complexes 6 only
transiently oxidatively add the allyl starting material as rapidly
as, for example, 1. In the absence of added nucleophile, the
carbonate (or alkoxide) base, formed via the oxidative addition
reaction (see Scheme 2), generates a carbon anion, which attacks
the Ru(IV) allyl to form the new olefin complexes.
Experimental Part
All reactions were carried out under a nitrogen atmosphere using
standard Schlenk techniques. All solvents were distilled under
nitrogen using standard drying agents. For the preparation of 7 we
have used both the ethyl and tert-butyl carbonates. Both of these
work equally well in terms of the isolated yield.
[Ru{1-(CH2-CHPh-CHdCH2)-2,3,4,5-tetramethylcyclopenta-
diene}(2,2′-dipyridyl)]PF6, 7a. A solution of PhCHdCH-CH2-
OCO2Et (0.0343 g, 0.166 mmol) in 2 mL of acetonitrile was added to
a brown solution of 6a (0.0481 g, 0.083 mmol) in 2 mL of acetonitrile.
The reaction mixture was stirred for 16 h at 60 °C, and then the solvent
was reduced under vacuum and ether was added to precipitate a brown
solid. The solid was collected, washed three times with ether, and then
dried under vacuum. Yield: 0.0499 g (92%). Anal. (%) Calcd for
C29H31N2F6PRu: C 53.29, H 4.78, N 4.29. Found: C 53.44, H 4.88, N
(16) Pool, J. A.; Bradley, C. A.; Chirik, P. J. A. Organometallics 2002,
21, 1271–1277.
(17) Riley, P. N.; Parker, J. R.; Fanwick, P. E.; Rothwell, I. P.
Organometallics 1999, 18, 3579–3583.
(18) Sadow, A.; Tilley, D. T. J. Am. Chem. Soc. 2003, 125, 7971–7977.
(19) Therrien, B.; Ward, T. R; Pinlkington, M.; Hoffmann, C.; Gilardoni,
F.; Weber, J. Organometallics 1998, 17, 330–337. (a) Therrien, B.; Koenig,
A.; Ward, T. R. Organometallics 1999, 18, 1565–1568.
(20) Bennett, M. A.; Edwards, A. J.; Harper, J. R.; Khimyak, T.; Willis,
A. C. J. Organomet. Chem. 2001, 629, 7–18.
(21) Onitsuka, K.; Ajioka, Y.; Matsushima, Y.; Takahashi, S. Organo-
metallics 2001, 20, 3274–3282.
(22) Faller, J. W.; D’Alliessi, D. G. Organometallics 2003, 22, 2749–
2757.
(23) Umezawa-Vizzini, K.; Lee, T. R. Organometallics 2003, 22, 3066–
3076.
(24) Ghebreyessus, K. Y.; Nelson, J. H. Inorg. Chim. Acta 2003, 350,
12–24.
Figure 1. Section of the 13C NMR spectrum of 7d showing the
four nonequivalent remaining methyl groups of the Cp moiety (500
MHz, CD3CN).
(25) Cadierno, V.; Diez, J.; Garcia-Alvarez, J.; Gimeno, J. Chem.
Commun. 2004, 1820–1821.

1594 Organometallics, Vol. 27, No. 7, 2008
Caldwell and Pregosin
Scheme 3
[Ru{1-(CH2-CHPh-CHdCH2)-2,3,4,5-tetramethylcyclopenta-
diene}(1,10-phenanthroline)]PF6, 7c. A solution of PhCHdCH-
CH2OCO2Et (0.0396 g, 0.192 mmol) in 2 mL of acetonitrile was
added to an orange solution of 6c (0.0579 g, 0.096 mmol) in 2 mL
of acetonitrile. The reaction mixture was stirred for 16 h at 60 °C,
and then the solvent was reduced under vacuum and ether was
added to precipitate an orange solid. The solid was collected,
washed three times with ether, and then dried under vacuum. Yield:
0.0633 g (97%). Anal. (%) Calcd for C31H31N2F6PRu: C 54.95, H
4.61, N 4.13. Found: C 55.13, H 4.82, N 4.14. MS: m/z 533 [M+].
1H NMR (500 MHz, CD3CN) δ: 1.36 (s); 1.38 (s); 2.05 (s); 2.34
(s) (4 Cp* Me), 2.31 (m); 2.45 (dd, J ) 14.4 Hz, 7.7 Hz) (CH2),
2.19 (d, J ) 8.1 Hz); 3.65 (d, J ) 12.5 Hz) (dCH2), 3.95 (m)
(CHdCH2), 4.59 (m) (CHPh), 7.21 (Ph para), 7.34 (Ph meta), 7.52
(Ph ortho), 7.96; 8.04; 8.05; 8.12; 8.56; 8.64; 9.42; 9.63 (8
phenanthroline protons). 13C{1H} NMR (125 MHz, CD3CN) δ:
7.4; 7.9; 8.4; 9.0 (4 Cp* Me), 27.5 (CH2), 51.9 (dCH2), 55.7
(CHPh), 81.2 (CCH3), 83.9 (CCH3), 86.9 (CHdCH2), 99.8 (CCH3),
100.8 (CCH3), 125.3, 125.5, 127.0 (Ph para), 127.5 (Ph ortho),
127.6, 127.7, 128.8 (Ph meta), 130.7, 130.9, 135.8, 136.5, 146.0,
146.2, 144.7 (Ph ipso), 153.9, 154.9.
Figure 2. Section of the 1H,1H NOESY showing the correlations
arising from the ortho 4,4′-dimethylbipyridine protons, H6,6′
.
Each of these protons reveals four NOEs: two each to the
proximate Cp methyl groups and (left column) two correlations
from protons Hc and Hd and (right column) two from protons
Ha and Hb (500 MHz, CD3CN).
4.95. MS: m/z 509 [M+]. 1H NMR (500 MHz, CD3CN) δ: 1.36 (s);
1.38 (s); 1.95 (s); 2.22 (s) (4 Cp* Me), 2.24; 2.40 (dd, J ) 14.1 Hz,
7.7 Hz) (CH2), 2.24; 3.56 (d, J ) 3.56 Hz) (CH2), 3.86 (m) (CHdCH2),
4.49 (m) (CHPh), 7.26 (Ph para), 7.36 (Ph meta), 7.52 (Ph ortho),
7.62; 7.69; 8.01; 8.09; 8.32; 8.35; 9.08; 9.32 (8 bipy protons). 13C{1H}
NMR (125 MHz, CD3CN) δ: 7.2; 7.8; 8.3; 8.7 (4 Cp* Me), 27.3 (CH2),
52.0 (dCH2), 55.8 (CHPh), 81.7 (CCH3), 84.4 (CCH3), 87.0
(CHdCH2), 99.4 (CCH3), 100.9 (CCH3), 106.6 (CCH3), 123.3, 123.5,
126.1, 126.4, 127.0 (Ph para), 127.5 (Ph ortho), 128.8 (Ph meta), 137.1,
137.9, 144.7 (Ph ipso), 153.8, 154.6.
[Ru{1-(CH2-CHPh-CHdCH2)-2,3,4,5-tetramethylcyclopenta-
diene}(4,4′-dimethyl-2,2′-dipyridyl)]PF6, 7b. A solution of PhCHd
CH-CH2OCO2Et (0.0307 g, 0.149 mmol) in 2 mL of acetonitrile
was added to an orange solution of 6b (0.0730 g, 0.120 mmol) in
2 mL of acetonitrile. The reaction mixture was stirred for 2.5 h at
60 °C, and then the solvent was reduced under vacuum and ether
was added to precipitate a brown solid. The solid was collected,
washed three times with ether, and then dried under vacuum. Yield:
0.0669 g. 1H NMR of this brown solid showed that approximately
10% of the material was unreacted complex 6b. The brown solid
was dissolved in 2 mL of acetonitrile, and a further 0.0034 g (0.016
mmol) of PhCHdCH-CH2CO2Et in 2 mL of acetonitrile was added.
The solution was stirred for 5 h at 60 °C, and then a brown solid
was isolated as described above. Yield: 0.0584 g (71%). Anal. (%)
Calcd for C31H35N2F6PRu · H2O: C 53.17, H 5.29, N 4.00. Found:
C 53.22, H 5.26, N 4.65. MS: m/z 537 [M+]. 1H NMR (500 MHz,
CD3CN) δ: 1.35 (s); 1.38 (s); 1.93 (s); 2.20 (s) (4 Cp* Me), 2.22;
2.39 (dd, J ) 14.4 Hz, 7.7 Hz) (CH2), 2.14 (d, J ) 8.2 Hz); 3.52
(d, J ) 12.5 Hz) (dCH2), 2.57 (s); 2.61 (s) (2 bipy Me), 3.79 (m)
(CHdCH2), 4.47 (m) (CHPh), 7.25 (Ph para), 7.36 (Ph meta), 7.51
(Ph ortho), 7.45; 7.52; 8.17; 8.20; 8.88; 9.10 (6 bipy protons).
13C{1H} NMR (125 MHz, CD3CN) δ: 7.2; 7.8; 8.4; 8.8 (4 Cp*
Me), 20.4; 20.6 (2 bipy Me), 27.4 (CH2), 51.5 (dCH2), 55.8
(CHPh), 81.5 (CCH3), 84.1 (CCH3), 86.2 (CHdCH2), 99.2 (CCH3),
100.5 (CCH3), 106.3 (CCH3), 123.8, 124.0, 127.0 (Ph para), 127.5
(Ph ortho), 127.6, 128.8, 128.8 (Ph meta), 144.8 (Ph ipso), 149.6,
150.4, 153.0, 153.9 154.1, 152.2.
[Ru{1-(CH2-CH(C6H4OMe)-CHdCH2)-2,3,4,5-tetramethyl-
cyclopentadiene}(4,4′-dimethyl-2,2′-dipyridyl)]PF6, 7d. A solu-
t
tion of 4-MeO-C6H4-CH(OCO2 Bu)-CHdCH2 (0.0502 g, 0.190
mmol) in 2 mL of acetonitrile was added to an orange solution of
6b (0.0576 g, 0.095 mmol) in 2 mL of acetonitrile. The reaction
mixture was stirred for 16 h at 60 °C, and then the solvent was
reduced under vacuum and ether was added to precipitate an ochre
solid. The solid was collected, washed three times with ether, and
dried under vacuum. Yield: 0.0644 (95%). Anal. (%) Calcd for
C32H37N2OF6PRu: C 54.01, H 5.24, N 3.94. Found: C 53.61, H
5.32, N 4.09. MS: m/z 567 [M+]. 1H NMR (500 MHz, CD3CN) δ:
1.35 (s); 1.37 (s); 1.93 (s); 2.18 (s) (4 Cp* Me), 2.17 (d, J ) 8.1
Hz); 2.35 (dd, J ) 14.5 Hz, 7.7 Hz) (CH2), 2.13; 3.50 (d, J ) 12.1
Hz) (dCH2), 2.57 (s); 2.61 (s) (2 bipy Me), 3.79 (CHdCH2), 3.79
(s) (OMe), 4.41 (m) (CHPh), 6.90 (Ph ortho), 7.42 (Ph meta), 7.44;
7.52; 8.17; 8.19; 8.87; 9.09; (6 bipy protons). 13C{1H} NMR (125
MHz, CD3CN) δ: 7.2; 7.8; 8.4; 8.8 (4 Cp* Me), 20.4; 20.6 (2 bipy
Me), 27.5 (CH2), 51.4 (dCH2), 55.1 (OMe), 55.3 (CHPh), 81.3
(CCH3), 84.1 (CCH3), 86.9 (CHdCH2), 99.1 (CCH3), 100.3 (CCH3),
106.3 (CCH3), 114.1 (Ph ortho), 123.8, 124.0, 127.0, 127.5, 128.5
(Ph meta), 137.0 (Ph ipso), 149.5, 150.3, 153.0, 153.9, 154.1, 154.2,
158.9 (Ph para).

Intramolecular Allylation of a Ru-Cp* Methyl Group
Organometallics, Vol. 27, No. 7, 2008 1595
[Ru{1-(CH2-CH2-CHdCH2)-2,3,4,5-tetramethylcyclopenta-
diene}(2,2′-dipyridyl)]PF6, 7e. A solution of CH2dCH-CH2O-
CO2 Bu (0.0275 g, 0.173 mmol) in 2 mL of acetonitrile was added
and then the solvent was reduced under vacuum and ether was
added to precipitate an ochre solid. The solid was collected, washed
three times with ether, and then dried under vacuum. Yield: 0.0137
g (52%). Anal. (%) Calcd for C25H31N2F6PRu.H2O: C 48.11, H
5.29, N 4.49. Found: C 48.39, H 5.43, N 5.26. MS: m/z 461 [M+].
1H NMR (400 MHz, CD2Cl2,) δ: 1.35 (s); 1.37 (s); 1.90 (s); 2.11
(s) (4 Cp* Me), 2.00; 3.39 (d, J ) 12.1 Hz) (CH2), 2.08 (d, J )
8.1 Hz); 2.12 (CH2), 2.61 (s); 2.65 (s) (2 bipy Me), 2.77 (m); 3.05
(m) (CH2), 3.80 (m) (CHdCH2), 7.40, 7.46, 8.05, 8.08, 8.82, 8.93
(6 bipy protons). 13C{1H} NMR (100 MHz, CD2Cl2) δ: 7.9; 8.4;
8.9, 9.4 (4 Cp* Me), 21.2; 21.3 (2 bipy Me), 21.4 (CH2), 39.5 (CH2),
54.8 (dCH2), 80.4 (CCH3), 82.6 (CCH3), 84.9 (CHdCH2), 98.1
(CCH3), 104.3 (CCH3), 108.7 (CCH3), 123.7, 124.0, 127.2, 127.5,
149.6, 150.4, 152.1, 153.3, 153.9, 154.0.
t
to a solution of 6a (0.0503 g, 0.087 mmol) in 2 mL of acetonitrile.
The reaction mixture was stirred for 16 h at 60 °C, the solvent was
removed under vacuum, and the residue was washed several times
with ether. The resulting red-brown solid was then dried under
vacuum. Yield: 0.0427 g (85%). MS: m/z 433 [M+]. 1H NMR (500
MHz, CD3CN) δ: 1.32 (s); 1.34 (s); 1.92 (s); 2.12 (s) (4 Cp* Me),
2.05 (d, J ) 8.6 Hz); 3.43 (d, J ) 12.5 Hz) (dCH2), 2.10; 2.12
(CH2), 2.72; 3.05 (m) (CH2), 3.87 (m) (CHdCH2), 7.60, 7.68, 8.00,
8.07, 8.31, 8.33, 9.06, 9.20 (8 bipy protons). 13C{1H} NMR (125
MHz, CD3CN) δ: 7.3, 7.7, 8.2, 8.7 (4 Cp* Me), 21.2 (CH2), 39.3
(CH2), 54.7 (dCH2), 80.7 (CCH3), 83.0 (CCH3), 85.5 (CHdCH2),
98.0 (CCH3), 104.4 (CCH3), 109.2 (CCH3), 123.2, 123.4, 126.1,
126.4, 137.0, 137.8, 153.5, 154.4, 154.5, 154.5.
[Ru{1-(CH2-CH2-CHdCH2)-2,3,4,5-tetramethylcyclopenta-
diene}(4,4′-dimethyl-2,2′-dipyridyl)]PF6, 7f. A solution of CH2dCH-
CH2OCO2 Bu (0.0137 g, 0.087 mmol) in 2 mL of acetonitrile was
added to a solution of 6b (0.0263 g, 0.043 mmol) in 1.5 mL of
acetonitrile. The reaction mixture was stirred for 16 h at 60 °C,
Acknowledgment. P.S.P. thanks the Swiss National Science
Foundation and the ETH Zurich for support, as well as the
Johnson Matthey organization for the loan of ruthenium salts.
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OM701248D