Cyclization accompanied with 1,2-phenyl migration in the protonation of ruthenium acetylide complex containing an allenyl group

Article abstract of DOI:10.1021/om101017p

Reaction of the ruthenium allenylidene complex [Ru]=C=C=CPh₂ (1, [Ru] = Cp(PPh₃)₂Ru) with the propargylic Grignard reagent R-C≡CCH₂MgBr (R = CH₃, CH₂CH ₃, Ph) yielded a mixture o

Full text of DOI:10.1021/om101017p

Organometallics 2010, 29, 6829–6836 6829
DOI: 10.1021/om101017p
Cyclization Accompanied with 1,2-Phenyl Migration in the Protonation
of Ruthenium Acetylide Complex Containing an Allenyl Group
Kuo-Hao Chen,† Yi Jhen Feng,† Hao-Wei Ma,† Ying-Chih Lin,*,† Yi-Hong Liu,† and
Ting-Shen Kuo‡
†Department of Chemistry, National Taiwan University, Taipei, Taiwan 106, Republic of China, and
‡Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan 116, Republic of China
Received October 28, 2010
Reaction of the ruthenium allenylidene complex [Ru]dCdCdCPh2 (1, [Ru] = Cp(PPh3)2Ru) with the
propargylic Grignard reagent R-CtCCH2MgBr (R = CH3, CH2CH3, Ph) yielded a mixture of two
acetylide complexes. The major products, [Ru]CtCCPh2C(R)dCdCH2 (2a, R = CH3; 2b, R =
CH2CH3; 2c, R = Ph), have an allenyne moiety, and the minor ones, [Ru]CtCCPh2CH2CtCR (3a,
R = CH3; 3b, R = CH2CH3; 3c, R = Ph), have a diyne ligand. The reaction of similar propargyl Grignard
reagent HCtCCH2MgBr with 1 yielded only the diyne complex 3d. Treatment of complexes 2a-2c with
HBF4 afforded the cyclization complexes 5a-5c, respectively, proceeding via a vinylidene intermediate. The
cyclization of the allenyl and the vinylidene groups is accompanied with a phenyl group migration. Complex
5b is fully characterized by a single-crystal X-ray diffraction analysis. Similar cyclization of complexes
2a and 2b, catalyzed by a Au phosphine complex, gave the ruthenium vinylidene complexes 6a and 6b,
respectively, with different selectivity from that of the protonation reaction. Au-catalyzed cyclization of the
diyne complex 3d yielded 6d, which is fully characterized by a single-crystal X-ray diffraction analysis.
Introduction
considerable increase in molecular intricacy accomplished in a
single synthetic step.1 Recently, a large number of research on
gold- and platinum-catalyzed cycloisomerization2 has been pub-
lished for both intramolecular and intermolecular applications.
Now it is recognized that gold and platinum complexes are useful
catalysts and can deliver a diverse array of cyclic products under
mild conditions.3 These products can be obtained with high
efficiency and excellent chemoselectivity. Unsaturated systems,
such as 1,5-, 1,6-, and 1,7-enyne compounds, provide access to
various products by reacting with a transition metal catalyst.4 It
is also known that reactions of functionalized alkyne catalyzed
also by a transition metal complex system could yield com-
plex organic compounds.5 In the past few years, our group and
others have reported several examples of enyne cycloisomeriza-
tions on metals to form various cyclic compounds.6 Allenes
are highly valuable synthetic precursors in organic chemistry.
Transition metal-catalyzed cycloisomerization of alkyne-
containing polyunsaturated compounds, such as enyne, diyne,
and dienyne, has been a focus of substantial attention due to the
*To whom correspondence should be addressed. E-mail: yclin@
ntu.edu.tw.
ꢀ
(1) (a) Benedetti, E.; Lemiere, G.; Chapellet, L. L.; Penoni, A.;
Palmisano, G.; Malacria, M.; Goddard, J. P.; Fensterbank, L. Org. Lett.
2010, 12, 4396–4399. (b) Hashmi, A. S. K. Chem. Rev. 2007, 107, 3180–3211.
(c) Jimenez-Nꢁunez, E.; Echavarren, A. M. Chem. Rev. 2008, 108, 3326–3350.
(d) F€urstner, A. Chem. Soc. Rev. 2009, 38, 3208–3221. (e) Michelet, V.; Toullec,
ꢁ
~
^
P. Y.; Genet, J.-P. Angew. Chem., Int. Ed. 2008, 47, 4268–4315. (f) Moreau, X.;
ꢀ
ꢁ
Goddard, J. P.; Bernard, M.; Lemiere, G.; Lopez-Romero, J. M.; Mainetti, E.;
ꢀ
Marion, N.; Mouries, V.; Thorimbert, S.; Fensterbank, L.; Malacria, M. Adv.
Synth. Catal. 2008, 350, 43–48. (g) Moreau, X.; Hours, A.; Fensterbank, L.;
Goddard, J. P.; Malacria, M.; Thorimbert, S. J. Organomet. Chem. 2009, 694,
ꢀ
ꢁ
561–565. (h) Marion, N.; Lemiere, G.; Correa, A.; Costabile, C.; Ramon, R. S.;
ꢁ
Moreau, X.; de Fremont, P.; Dahmane, R.; Hours, A.; Lesage, D.; Tabet, J. C.;
Goddard, J. P.; Gandon, V.; Cavallo, L.; Fensterbank, L.; Malacria, M.; Nolan,
S. P. Chem.;Eur. J. 2009, 15, 3243–3260. (i) Harrak, Y.; Simonneau, A.;
Malacria, M.; Gandon, V.; Fensterbank, L. Chem. Commun. 2010, 46, 865–867.
(j) Molawi, K.; Delpont, N.; Echavarren, A. M. Angew. Chem., Int. Ed. 2010,
49, 3517–3519. (k) Sethofer, S. G.; Mayer, T.; Toste, F. D. J. Am. Chem. Soc.
2010, 132, 8276–8277. (l) Jurberg, I. D.; Odabachian, Y.; Gagosz, F. J. Am.
Chem. Soc. 2010, 132, 3543–3552.
(2) (a) Hashmi, A. S. K. Gold Bull. 2004, 37, 51–65. (b) Hashmi, A. S. K.
Angew. Chem., Int. Ed. 2005, 44, 6990–6993. (c) Bruneau, C. Angew. Chem.,
Int. Ed. 2005, 44, 2328–2334. (d) Hashmi, A. S. K.; Frost, T. M.; Bats, J. W.
J. Am. Chem. Soc. 2000, 122, 11553–11554. (e) Asao, N.; Takahashi, K.; Lee,
S.; Kasahara, T.; Yamamoto, Y. J. Am. Chem. Soc. 2002, 124, 12650–12651.
(f) Asao, N.; Nogami, T.; Lee, S.; Yamamoto, Y. J. Am. Chem. Soc. 2003, 125,
10921–10925. (g) Asao, N.; Aikawa, H.; Yamamoto, Y. J. Am. Chem. Soc. 2004,
126, 7458–7459. (h) Reetz, M. T.; Sommer, K. Eur. J. Org. Chem. 2003, 3485–
3496. (i) Wei, C.; Li, C. J. J. Am. Chem. Soc. 2003, 125, 9584–9585. (j) Shi, Z.;
He, C. J. Org. Chem. 2004, 69, 3669–3671. (k) Kennedy-Smith, J. J.; Staben,
S. T.; Toste, F. D. J. Am. Chem. Soc. 2004, 126, 4526–4527. (l) Barluenga, J.;
(3) Zhang, L.; Sun, J.; Kozmin, S. A. Adv. Synth. Catal. 2006, 348,
2271–2296.
(4) (a) Aubert, C.; Buisine, O.; Malacria, M. Chem. Rev. 2002, 102,
813–834. (b) Trost, B. M.; Krische, M. J. Synlett 1998, 1–16. (c) Ojima, I.;
Tzamarioudaki, M.; Li, Z.; Donovan, R. J. Chem. Rev. 1996, 96, 635–662.
(d) Luzung, M. R.; Markham, J. P.; Toste, F. D. J. Am. Chem. Soc. 2004, 126,
10858–10859.
(5) (a) Shiu, Y. T.; Madhushaw, R. J.; Li, W. T.; Lin, Y. C.; Lee,
G. H.; Peng, S. M.; Liao, F. L.; Wang, S. L.; Liu, R. S. J. Am. Chem. Soc.
1999, 121, 4066–4067. (b) Patil, N. T.; Yamamoto, Y. Handb. Cyclization
React. 2010, 1, 457–525.
(6) (a) Yen, Y. S.; Lin, Y. C.; Huang, S. L.; Liu, Y. H.; Sung, H. L.;
Wang, Y. J. Am. Chem. Soc. 2005, 127, 18037–18045. (b) Cheng, C. W.;
Kuo, Y. C.; Chang, S. H.; Lin, Y. C.; Liu, Y. H.; Wang, Y. J. Am. Chem. Soc.
2007, 129, 14974–14980. (c) Tanaka, D.; Sato, Y.; Mori, M. Organometal-
lics 2006, 25, 799–801. (d) Kinder, R. E.; Widenhoefer, R. A. Org. Lett.
2006, 8, 1967–1969. (e) Miyanohana, Y.; Chatani, N. Org. Lett. 2006, 8,
2155–2158. (f) Chen, Y.; Lee., C. J. Am. Chem. Soc. 2006, 128, 15598–
15599.
ꢁ
ꢁ
~ ꢁ
Dieguez, A.;Fernandez, A.; Rodríguez, F.; Fananas, F. J. Angew. Chem., Int. Ed.
2006, 45, 2091–2093.
r
2010 American Chemical Society
Published on Web 11/24/2010
pubs.acs.org/Organometallics

6830 Organometallics, Vol. 29, No. 24, 2010
Chen et al.
Their exceptional structure is an indispensable requirement for
the synthesis of many structurally appealing and biologically
functional compounds.7 It is known that the CdC bond of
allenes is around 10 kcal/mol less stable than that of simple
alkenes,8 making them appreciably more reactive. In transition
metal-catalyzed reactions their reactivity is closer to that of
alkynes than that of simple alkenes. Nonetheless, allenes display
a distinct and complementary reactivity profile.9 It has been well
known that the functionalized allenynes can be catalyzed by
Au(I) to yield cycloaddition organic compounds.10 Over the past
30 years, the use of organometallic reagents for the synthesis of
allenes has been highly developed.11 One common method for
the preparation of various allenes is the metal-mediated SN2
nucleophilic substitution of propargylic electrophiles. The leav-
ing group on the electrophilic propargylic moiety can be an
acetal,12 an acetate,13 an epoxide,14 an ether,15 a halide,16 or a
sulfonate.17,18 The corresponding organometallic nucleophile
can be either a Grignard reagent,19 an organocopper,20 an
organozinc,21 or an organoboronate22 derivative. We reported
that 1,5-enyne and 1,5-diyne could bind with ruthenium to form
metal acetylide complexes, which undergo novel cyclization and/
or metal migration reactions.6 Noticing several recent reports
mentioning cyclization reactions of organic allenyl and alkynyl
compounds,23 we imagined developing procedures employing
allenes for the synthesis of cyclic compounds. In particular, we
concentrated our attention on the reactivity of an allenyl group
bonded to another unsaturated ligand, which is also coordinated
to a transition metal. We thus explored the cyclization reaction of
ligands on transition metals as well as the catalytic reaction
of the ruthenium allenyne complex. Herein we report the reac-
tion of the ruthenium allenyne complex with HBF4, causing
formation of the carbene complex containing a five-membered
ring. This cyclization reaction is accompanied with a 1,2-phenyl
migration.24 Gold-complex-catalyzed cyclization of the same
ruthenium allenyne as well as diyne complexes leading to the
formation of different types of five-membered rings is also
reported.
Results and Discussion
Phenyl Migration in Cyclization. Treatment of the diphe-
nyl allenylidene ruthenium complex 125 with the propargylic
Grignard reagent CH3CtCCH2MgBr, which was prepared
from propargylic bromide, CH3CtCCH2Br, and magne-
sium in diethyl ether,26-29 yielded a mixture of two yellow
acetylide complexes, 2a and 3a, in a ratio of 10:1. The major
complex, 2a, contains an allenyne ligand on the ruthenium
metal with two phenyl groups at Cγ and one methyl group
at Cδ. The diyne ligand in 3a, however, has a terminal
methyl group. Similarly reactions of 1 with two other
propargylic Grignard reagents, CH3CH2CtCCH2MgBr
and PhCtCCH2MgBr, also afforded mixtures of 2b and
3b in a ratio of 5:1 and 2c and 3c in a ratio of 10:7, respectively
(Scheme 1). The results may imply that all these propargylic
Grignard reagents exist in two tautomeric forms, which
presumably are in fast equilibrium,26 leading to the forma-
tion of 2 and 3.30 Interestingly, when the propargyl Grignard
reagent HCtCCH2MgBr was used, only the diyne complex
3d was isolated. Complexes 2a-2c were purified by chroma-
tography using a column packed with Al2O3. Complexes
2 and 3 were characterized by spectroscopic methods. In
addition, complex 2b was further characterized by a single-
crystal X-ray diffraction analysis. In the 1H NMR spectrum
of 2a, the quartet resonance at δ 4.51, coupling with the
methyl protons with JH-H = 2.7 Hz, is assigned to the
terminal allenyl protons of the ligand. The corresponding
resonances for the allenyl protons of 2b and 2c appear at δ
4.48 as a triplet with JH-H = 3.6 Hz and δ 4.67 as a singlet,
respectively. In the 1H NMR spectrum of 3a from the
mixture of 2a and 3a, the quartet resonance of the methylene
(7) (a) Krause, N.; Hashmi, A. S. K., Eds. Modern Allenes Chemistry;
€
Wiley-VCH: Weinheim, 2004. (b) Hoffmann-Roder, A.; Krause, N. Angew.
€
Chem., Int. Ed. 2002, 41, 2933–2935. (c) Krause, N.; Hoffmann-Roder, A.;
Canisius, J. Synthesis 2002, 1759–1774. (d) Marshall, J. A. J. Org. Chem.
2007, 72, 8153–8166.
(8) (a) Saget. T.; Cramer. N. Angew. Chem., Int. Ed. 2010, 49, DOI:
10.1002/anie.201004795. (b) Padwa, A.; Filipkowski, M. A.; Meske, M.;
Murphree, S. S.; Watterson, S. H.; Ni, Z. J. Org. Chem. 1994, 59, 588–
596.
(9) (a) Zimmer, R.; Dinesh, C. U.; Nandanan, E.; Khan, F. A. Chem.
Rev. 2000, 100, 3067–3125. (b) Hashmi, A. S. K. Angew. Chem., Int. Ed.
2000, 39, 3590–3593. (c) Ma, S. Acc. Chem. Res. 2003, 36, 701–712.
(d) Ma, S. Top. Organomet. Chem. 2005, 14, 1–33. (e) Ma, S. Chem. Rev.
2005, 105, 2829–2871.
(10) (a) Oh, C. H.; Karmakar, S. J. Org. Chem. 2009, 74, 370–374.
(b) Lin, G. Y.; Yang, C. Y.; Liu, R. S. J. Org. Chem. 2007, 72, 6753–6757.
(11) (a) Pasto, D. J. Tetrahedron 1984, 40, 205–2827. (b) Brummond,
K. M.; DeForrest, J. E. Synthesis 2007, 6, 795–818. (c) Krause, N.;
€
Hoffmann-Roder, A. Tetrahedron 2004, 60, 11671–11694.
(12) Alexakis, A.; Mangeney, P.; Normant, J. F. Tetrahedron Lett.
1985, 26, 4197–4200.
(13) Rona, P.; Crabbe, P. J. Am. Chem. Soc. 1968, 90, 4733–4734.
(14) Herr, R. W.; Wieland, D. M.; Johnson, C. R. J. Am. Chem. Soc.
1970, 92, 3813–3814.
5
group is at δ 3.07 with JH-H = 2.4 Hz, coupling with the
CH3 resonance at δ 1.45. The corresponding resonances for
(15) Alexakis, A.; Marek, I.; Mangeney, P.; Normant, J. F. J. Am.
Chem. Soc. 1990, 112, 8042–8047.
(16) Mae, M.; Hong, J. A.; Xu, B.; Hammond, G. B. Org. Lett. 2006,
8, 479–482.
(24) Gheorghe, A.; Quiclet-Sire, B.; Vila, X.; Zard, S. Z. Tetrahedron
2007, 63, 7187–7212.
(25) Bruce, M. I.; Low, P. J.; Tiekink, E. R. T. J. Organomet. Chem.
1999, 572, 3–10.
(17) Westmuze, H.; Vermeer, P. Synthesis 1979, 390–392.
(18) (a) Macomber, R. S. J. Am. Chem. Soc. 1977, 99, 3072–3075.
(b) Myers, A. G.; Zheng, B. J. Am. Chem. Soc. 1996, 118, 4492–4493.
(c) Chedid, R. B.; Brummer, M.; Wibbeling, B.; Frohlich, R.; Hoppe, D.
Angew. Chem., Int. Ed. 2007, 46, 3131–3134.
(19) Nantz, M. H.; Bender, D. M.; Janaki, S. Synthesis 1993, 577–578.
(20) (a) Macdonald, T. L.; Reagan, D. R. J. Org. Chem. 1980, 45,
4740–4747. (b) Deutsch, C.; Lipshutz, B. H.; Krause, N. Angew. Chem., Int.
Ed. 2007, 46, 1650–1653.
(21) Bertozzi, F.; Crotti, P.; Macchia, F.; Pineschi, M.; Arnold, A.;
Feringa, B. L. Tetrahedron Lett. 1999, 40, 4893–4896.
(22) Ito, H.; Sasaki, Y.; Sawamura, M. J. Am. Chem. Soc. 2008, 130,
15774–15775.
(23) (a) Gockel, B.; Krause, N. Eur. J. Org. Chem. 2010, 311–316.
(b) Ueda, M.; Sato, A.; Ikeda, Y.; Miyoshi, T.; Naito, T.; Miyata, O. Org. Lett.
2010, 12, 2594–2597. (c) Teng, T. M.; Liu, R. S. J. Am. Chem. Soc. 2010,
132, 9298–9300. (d) Toullec, P. Y.; Blarre, T.; Michelet, V. Org. Lett. 2009,
11, 2888–2891.
(26) (a) Acharya, H. P.; Miyoshi, K.; Kobayashi, Y. Org. Lett. 2007,
9, 3535–3538. (b) Karunakar, G. V.; Periasamy, M. Tetrahedron Lett. 2006,
47, 3549–3552. (c) Reich, H. J.; Holladay, J. E.; Walker, T. G.; Thompson,
J. L. J. Am. Chem. Soc. 1999, 121, 9769–9780.
(27) (a) Stadler, P. A.; Nechvatal, A.; Frey, A. J.; Eschenmoser, A.
Helv. Chim. Acta 1957, 40, 1373–1409. (b) Sondheimer, F.; Wolovsky, R.;
Ben-Efraim, D. A. J. Am. Chem. Soc. 1961, 83, 1686–1691. (c) Sondheimer,
F.; Amiel, Y.; Gaoni, Y. J. Am. Chem. Soc. 1962, 84, 270–274. (d) Viola, A.;
MacMillan, J. H. J. Am. Chem. Soc. 1968, 90, 6141–6145.
(28) (a) Mesnard, D.; Miginiac, L. J. Organomet. Chem. 1990, 397,
€
127–137. (b) Eckenberg, P.; Groth, U.; Kohler, T. Liebigs Ann. Chem. 1994,
673–677. (c) Hernandez, E.; Soderquist, J. A. Org. Lett. 2005, 7, 5397–5400.
(d) Zhang, L.; Kozmin, S. A. J. Am. Chem. Soc. 2004, 126, 10204–10205.
(29) Yanagisawa, A.; Habaue, S.; Yamamoto, H. Tetrahedron 1992,
48, 1969–1980.
(30) (a) Cadierno, V.; Gamasa, M. P.; Gimeno, J. Coord. Chem. Rev.
2004, 248, 1627–1657. (b) Alonso, F.; Beletskaya, I. P.; Yus, M. Chem. Rev.
2004, 104, 3079–3159.

Article
Organometallics, Vol. 29, No. 24, 2010 6831
Scheme 1
typical Ru-C single bond.31 The bond angle for Ru(1)-
C(1)-C(2) is 170.79(16)°. The C(1)-C(2) bond length is
˚
1.207(2) A, and the corresponding bond angle for C(1)-
C(2)-C(3) is 173.5(2)°, showing a CtC triple-bond char-
acter. The bond angle for C(6)-C(5)-C(4) is 177.6(2)°, and
bond lengths for C(4)-C(5) and C(5)-C(6) are 1.305(3) and
˚
1.298(3) A, respectively, indicating the allenyl character.
The application of propargylic bromide to form a mixture
of propargylic and allenylic Grignard reagents via tautomer-
ization has been reported, and treatment of cyclohexanone
with this Grignard reagent produced the homopropargylic
alcohol compound in good yield. Addition of the propargylic
tautomer shows a high selectivity over that of the allenylic
tautomer.26 However, in our system, treatment of the alle-
nylidene complex with the propargylic Grignard reagent
generated the allenyne products 2a-2c, with a different se-
lectivity favoring addition of the allenylic tautomer of the
Grignard reagent.
Treatment of complex 2b with HBF4 in diethyl ether gave a
pink powder (4b) in about 3 min as a precipitate at -78 °C,
which was purified by filtration. Presumably complex 4b is a
1
cationic vinylidene complex on the basis of its H and 31P
NMR data. Complex 4b appeared in solution for only a short
period of time at room temperature. The 1H NMR spectrum
of 4b shows two triplet peaks at δ 4.96 and 4.75 both with
JH-H = 3.3 Hz, assigned to the methylene protons of the
allenyl group and the proton of the vinylidene ligand,
respectively. In the 31P NMR spectrum, the singlet peak at
δ 41.78 assigned to 4b appears within the normal chemical
1
shift range of a ruthenium vinylidene complex. In the H
NMR spectrum of the deuteration product obtained from
CF3COOD, the triplet vinylidene resonance at δ 4.75 was not
observed.
When a CHCl3 solution of complex 4b was stirred con-
tinually for about 3 h at room temperature, the dark red
complex 5b, containing a five-membered ring, was isolated in
high yield. Similarly two analogous derivatives, 5a and 5c,
were obtained from protonations of 2a and 2c, respectively
1
(Scheme 1). In the H NMR spectrum of 5b, two singlet
peaks at δ 6.34 and 5.87 are assigned to the terminal
methylene protons of the vinyl group and two mutiplet peaks
at δ 2.61 and 2.24 are assigned to methylene protons of the
ethyl group. The 31P NMR spectrum of 5b shows two
doublet resonances at δ 45.51 and 43.89 with JP-P = 30.0
Hz. Both spectra reveal the presence of a stereogenic carbon
center in 5b. Comparison of the 1H,13C-HSQC and 1H,13C-
HMBC spectra of 2b and 5b disclose important structure
information of two phenyl groups. On the basis of the
1H,13C-HSQC spectrum of 2b, the 13C resonance at δ 57.30
Figure 1. ORTEP plot of 2b. Hydrogens and phenyl groups
except the C(ipso) atoms on the phosphorus ligands have been
˚
omitted for clarity. Selected bond distances (A) and angles (deg):
Ru(1)-P(1), 2.2871(5); Ru(1)-P(2), 2.2837(5); Ru(1)-C(1),
2.0212(18); C(1)-C(2), 1.207(2); C(2)-C(3), 1.483(2); C(3)-C(4),
1.562(3); C(4)-C(5), 1.305(3); C(5)-C(6), 1.298(3); C(4)-C(7),
1.506(3); C(7)-C(8), 1.508(3); C(2)-C(1)-Ru(1), 170.79(16);
C(1)-C(2)-C(3), 173.5(2); C(7)-C(4)-C(3), 117.38(17); C(4)-
C(7)-C(8), 115.72(19); C(6)-C(5)-C(4), 177.6(2).
1
is assigned to the tertiary Cγ, which, in the H,13C-HMBC
spectrum of 2b, correlates with two 1H resonance peaks at δ
7.31 and 7.42, assigned to two aromatic protons at different
phenyl groups. This indicates that two phenyl groups are
1
bonded to the same carbon atom. However, in the H,13C-
the methylene protons of 3b and 3c appear at δ 3.11 and 3.34,
respectively.
HMBC spectrum, the 1H resonance at δH 6.76 correlates to
that at δC 163.26, assigned to Cγ, and the other 1H resonance
at δH 6.81 correlates to a relatively upfield 13C resonance at
δC 64.25 assigned to Cδ. This clearly reveals that, in 5b, two
phenyl groups are separately bonded to two different neigh-
boring carbon atoms, with a significantly dissimilar chemical
shift of δ 64.25 versus 163.26, resulting from migration of one
Single crystals of 2b were obtained from a mixture of
CH3OH/CH2Cl2. The molecular structure of 2b was deter-
mined by an X-ray diffraction analysis, and an ORTEP
drawing is shown in Figure 1. In this acetylide complex,
˚
the bond length of Ru(1)-C(1) of 2.0212(18) A shows a
1
phenyl group from Cγ to Cδ. Also in the H,13C-HMBC
spectrum of 5b, the resonance of the carbene carbon at δC
292.68 correlates to two vinyl proton resonances at δH 5.87
(31) Bustelo, E.; Tenorio, M. J.; Puerta, M. C.; Valerga, P. Organo-
metallics 1999, 18, 4563–4573.

6832 Organometallics, Vol. 29, No. 24, 2010
Chen et al.
Scheme 2
˚
bonds, and the bond lengths of C(2)-C(6) of 1.327(5) A and
˚
C(4)-C(5) of 1.354(5) A are typical of CdC double bonds.
The presence of the five-membered ring reveals that a C-C
bond formation took place between CR and the central
carbon of the allenyl moiety of 2b. Furthermore, two adja-
cent phenyl groups of 5b are now bound separately with C(3)
and C(4), a result of a 1,2-phenyl migration.
Figure 2. ORTEP plot of 5b. Hydrogens and phenyl groups
except the C(ipso) atoms on the phosphorus ligands have been
˚
omitted for clarity. Selected bond distances (A) and angles (deg):
A possible mechanism for the transformation from com-
plex 2b to 5b is shown in Scheme 2. In this mechanism,
protonation of complex 2b from HBF4 leads first to forma-
tion of the vinylidene complex 4b, and then cyclization30,32
occurs, leading to C-C bond formation between the central
carbon atom of the terminal allenyl moiety and CR, giving
the cationic five-membered-ring ligand in A. Then a 1,2-
phenyl migration33,34 could take place for one of the geminal
phenyl groups to give C with a stereogenic carbon center.
Eventually, establishment of a ruthenium carbene bond
results in the formation of 5b.
Ru(1)-P(1), 2.3439(9); Ru(1)-P(2), 2.3478(9); Ru(1)-C(1),
1.980(3); C(1)-C(2), 1.484(4); C(2)-C(3), 1.546(4); C(3)-C(4),
1.512(5); C(4)-C(5), 1.354(5); C(1)-C(5), 1.451(5); C(2)-C(6),
1.327(5); C(3)-C(7), 1.558(5); C(7)-C(8), 1.520(5); C(2)-
C(1)-Ru(1), 130.9(2); C(1)-C(2)-C(3), 110.3(3); C(4)-
C(3)-C(2), 100.9(3); C(5)-C(4)-C(3), 110.8(3); C(4)-C(5)-
C(1), 114.2(3); C(5)-C(1)-C(2), 103.2(3); C(2)-C(3)-C(7),
111.4(3); C(8)-C(7)-C(3), 114.7(3).
and 6.34. Therefore, CR is now neighboring the terminal
vinyl moiety, revealing that 5b is a cyclic complex. Hence
transformation from 2b to 5b involves formation of a five-
membered ring accompanied with a 1,2-phenyl migration.
Complexes 5a and 5c show similar characteristic data in their
NMR spectra. The resonance of the vinyl proton at Cβ of 5a
at δ 7.25 is overlapped in the aromatic region but is ob-
servable in the 2D-HSQC NMR spectrum.
When one of the phosphine ligands is replaced by a phos-
phite P(OPh)3, the same nucleophilic addition of propargylic
Grignard reagents to the analogous allenylidene complex was
also observed, giving similar allenyne complexes.30 From
[Ru0]dCdCdCPh2 (10 [Ru0] = Cp(PPh3)(P(OPh)3)Ru) and
corresponding propargylic Grignard reagents, analogous mix-
tures of 2a0 and 3a0 (10:1) and 2b0 and 3b0 (1:1) could be isolated.
1
Single crystals of 5b were obtained from a mixture of
hexane/CH2Cl2 at 5 °C, and the structure was determined by
an X-ray diffraction analysis. An ORTEP drawing of com-
plex 5b is shown in Figure 2. One of two phenyl groups
originally at Cγ is indeed migrated to Cδ, and this indicates
that the cyclization reaction is accompanied with a 1,2-
phenyl migration.32 The Ru(1)-C(1) bond distance of
In the H NMR spectrum of 2b0, the resonance at δ 4.44 is
assigned to the terminal allenyl protons of the ligand, and that
of the methylene group is at δ 2.22 and 2.07. The corresponding
resonances for the allenyl protons of 2a0 appear at δ 4.33. The
31P NMR spectrum of 2b0 shows two doublet resonances at δ
139.07 and 52.81 with JP-P = 67.0 Hz; the two doublet 31P
resonances of 2a0 are at δ 139.31 and 53.02 with Jp-p = 67.1 Hz.
In the 1H NMR spectrum of 3b0, the broad singlet resonance at
δ 2.99 is assigned to the methylene group. Two doublet 31P
˚
1.980(3) A is in the range of typical RudC carbene double
(32) (a) Madhushaw, R. J.; Lin, M. Y.; Sohel, S. M. A.; Liu, R. S.
J. Am. Chem. Soc. 2004, 126, 6895–6899. (b) Yuan, L. M.; Madhushaw,
R. J.; Liu, R. S. J. Org. Chem. 2004, 69, 7700–7704. (c) Bakalbassis, E. G.;
Spyroudis, S.; Tsiotra, E. J. Org. Chem. 2006, 71, 7060–7062. (d) Schmittel,
M.; Mahajan, A. A.; Bucher, G.; Bats, J. W. J. Org. Chem. 2007, 72, 2166–
(33) Bruneau, C.; Dixneuf, P. H. Chem. Commun. 1997, 507–512.
€
(34) (a) Cordaro, J. G.; Stein, D.; Grutzmacher, H. J. Am. Chem. Soc.
2006, 128, 14962–14971. (b) Takahashi, M.; Sekine, N.; Fujita, T.;
Watanabe, S.; Yamaguchi, K.; Sakamoto, M. J. Am. Chem. Soc. 1998,
120, 12770–12776. (c) Zimmerman, H. E.; Wilson, J. W. J. Am. Chem. Soc.
1964, 86, 4036–4042. (d) Zimmerman, H. E.; Rieke, R. D.; Scheffer, J. R.
J. Am. Chem. Soc. 1967, 89, 2033–2047. (e) Zimmerman, H. E.; Lewin, N.
J. Am. Chem. Soc. 1969, 91, 879–886. (f) Zimmerman, H. E.; Hancock,
K. G. J. Am. Chem. Soc. 1968, 90, 3749–3760.
ꢁ
2173. (e) Luzung, M. R.; Mauleon, P.; Toste, F. D. J. Am. Chem. Soc. 2007,
129, 12402–12403. (f) Otto, S.; Roodt, A. Inorg. Chem. Commun. 2008, 11,
114–116. (g) Nakazaki, S. A.; Usuki, J.; Tomooka, K. Synlett 2008, 2064–
2068. (h) Agrawal, M. K.; Ghosh, P. K. J. Org. Chem. 2009, 74, 7947–7950.
(i) Siebert, M. R.; Osbourn, J. M.; Brummond, K. M.; Tantillo, D. J. J. Am.
Chem. Soc. 2010, 132, 11952–11966.

Article
Organometallics, Vol. 29, No. 24, 2010 6833
Scheme 3
HMBC spectrum of 6d, long-range C-H correlations are
observed between the resonances of the methylene group at
δ 3.37 and four remaining carbon atoms of the five-membered
ring at δ 142.65, 123.97, 119.38, and 61.41. These NMR
data clearly reveal formation of a five-membered ring from
cycloaddition of the terminal alkynyl group with the acetylide
ligand.
Single crystals of 6d were obtained by diffusion of diethyl
ether into a solution of 6d in dichloromethane. The structure
was confirmed by an X-ray diffraction analysis. Figure 3
shows an ORTEP drawing of 6d with selected bond lengths
and angles. The molecular structure reveals a typical vinylidene
Figure 3. ORTEP plot of 6d. Hydrogens and phenyl groups
except the C(ipso) atoms on the phosphorus ligands have been
˚
omitted for clarity. Selected bond distances (A) and angles (deg):
Ru(1)-P(1), 2.3326(12); Ru(1)-P(2), 2.3710(15); Ru(1)-C(1),
1.851(5); C(1)-C(2), 1.313(6); C(2)-C(3), 1.569(7); C(3)-C(4),
1.570(7); C(4)-C(5), 1.465(9); C(5)-C(6), 1.339(8); C(2)-C(6),
1.449(7); C(3)-C(7), 1.532(8); C(3)-C(13), 1.537(7); C(2)-
C(1)-Ru(1), 169.8(4); C(1)-C(2)-C(3), 129.9(5); C(6)-
C(2)-C(3), 105.3(4); C(5)-C(6)-C(2), 113.9(6); C(6)-C(5)-
C(4), 111.1(6); C(5)-C(4)-C(3), 106.0(5); C(2)-C(3)-C(4),
102.9(4).
˚
skeleton with the a bond length of Ru(1)-C(1) of 1.851(5) A
resonances at δ 140.01 and 53.35 with Jp-p = 66.7 Hz are
assigned to P(OPh)3 and PPh3, respectively. Complex 3a0 shows
similar characteristic data in the 1H and 31P spectra. Treatment
of 2a0 with HBF4 also gave the cationic five-membered-ring
complex 5a0, which has two stereogenic centers. Complex 5a0,
produced in two diastereomers, is identified by two sets of two
˚
and C(1)-C(2) of 1.313(6) A. The Ru(1)-C(1)-C(2) bond
angle of 169.8(4)° is slightly bent from a linear arrangement,
which is possibly due to the steric effect between the two phenyl
groups of the five-membered ring and two PPh3 ligands. The
˚
bond length of C(5)-C(6) is 1.339(8) A, indicating a double
doublet 31P resonances appearing at δ 135.41/51.87 with Jp-p
=
bond.
It is well known that the cationic Au(PPh3)þ catalyst could
effectively activate the terminal CtC triple bond.3 A mech-
anism for the formation of complex 6d is thus suggested as
follows. First, the terminal alkynyl group of complex 3d may
coordinate to the unsaturated gold complex to form the
intermediate D with a π-coordination mode; see Scheme 3.
Cyclization of this alkynyl group with the acetylide β-carbon
results in C-C bond formation to give the intermediate E.
Finally, extrusion of gold catalyst from the intermediate
E leads to formation of the cationic ruthenium vinylidene
complex 6d with a cyclopentene ring (Scheme 3).3 The C-C
bond formation takes place between Cβ of the acetylide
ligand and the methyne carbon of the terminal triple bond.
This regioselectivity is different from that of the C-C bond
formation occurring in the protonation reactions of the
allenyne complexes mentioned above.
Therefore, in addition to the cyclization of the diyne ligand
of 3d, reactions of complexes 2a and 2b, containing an
allenyne moiety, were explored under the same reaction
conditions in the presence of gold catalyst, and cyclization,
involving similar C-C bond formation to that in the gold-
complex-catalyzed reaction of 3d, was observed yielding 6a
and 6b, respectively. As shown in Scheme 4, treatment of
complexes 2a and 2b containing the allenyne moiety with a
catalytic amount of gold complex Au(PPh3)Cl/AgSbF6 in
CH2Cl2 at room temperature afforded complexes 6a and 6b,
respectively.
55.1 Hz and δ 134.97/49.28 with Jp-p = 55.3 Hz. Similarly
complex 5b0 was obtained from 2b0. The 31P resonances of 5b0
appear at δ 132.28/51.34 and 125.03/47.02, both with Jp-p
=
54.2 Hz. However, complexes 5a0 and 5b0 are unstable in
chloroform and, in 3 h, decomposed to give unidentifiable
products. When a chelating diphenylphosphinoethane (dppe)
ligand replaces the two PPh3 ligands, even the allenyne
complexes are too reactive to be isolated. No further attempt
was made to isolate or to explore the reactivity of these
products.
Cyclization by Au Complex. As illustrated in Scheme 1,
transformation of the yellow acetylide complex [Ru]Ct
CC(Ph)2CH2CtCH (3d) to give complex 6d, containing a
vinylidene ligand with a five-membered ring, was catalyzed
by AuPPh3SbF6,3,4 which was prepared from AgSbF6 and
AuPPh3Cl in hydrous CH2Cl2. The pink ruthenium vinyli-
dene complex 6d was obtained in 88% yield. This product is
characterized by NMR and single-crystal X-ray diffraction
analysis. The 1H NMR spectrum of complex 6d displays two
multiplet resonances at δ 5.77 and 5.00 assigned to olefinic
protons, and the resonance at δ 3.37 is assigned to the unique
methylene group of the ring. In order to gain further infor-
mation supporting the proposed structure of complex 6d,
2D-NMR techniques, including 1H,1H-COSY, 1H,13C-
HSQC, and 1H,13C-HMBC, are employed. The 1H,1H-COSY
spectrum of complex 6d shows cross-peaks correlating three
resonances at δ 3.37 and 5.00, 5.77. The HSQC spectrum shows
two sets of cross-peaks correlating resonances of the two
olefinic protons at δH 5.00 and 5.77 to the 13C resonances of
different carbons at δC 123.97 and 119.38, respectively. In the
Scheme 4 also shows a plausible mechanism for the trans-
formation. The reaction pathway is proposed on the basis
of the fact that the cationic Au(PPh3)þ catalyst preferably

6834 Organometallics, Vol. 29, No. 24, 2010
Chen et al.
Scheme 4
Protonation of these complexes affords 5a-5c by a cycliza-
tion involving the terminal allenyl group and the CdC bond
of the vinylidene group of the intermediate complex 4,
followed by a 1,2-phenyl migration. Cyclization of 3d cata-
lyzed by a gold complex involves a cyclization of diyne,
giving the vinylidene complex 6d with a cyclopentene ring.
The π-coordination of the terminal CtC triple bond of 3d to
Au, followed by a cyclization, results in formation of 6d.
Cyclization of the allenyne moiety of 2a and 2b by a gold
catalyst similarly proceeds via coordination of the allenyl
moiety to Au.
Experimental Section
triggered allenyl coordination to form the intermediate
F.27,35-37 Cyclization of the acetylide CtC triple bond with the
Au-complexed allenyl group of the intermediate F possibly
proceeds by an electrophilic addition of the allenyl group to the
acetylide β-carbon leading to G. Then, hydrolysis of the inter-
mediate G occurred, causing extrusion of the gold catalyst and
formation of the cationic ruthenium vinylidene complex 6 with
a cyclopentene moiety; see Scheme 4. Previously reported gold-
catalyzed reactions in the literature revealed that the gold-
catalyzed rearrangement and/or cyclization of 1,5-allenynes
could produce cross-conjugated trienes containing a five- or
six-membered ring.35a Hydrative carbocyclization of 1,5-alle-
nynes catalyzed by a gold catalyst gave cyclized ketones chem-
oselectively containing a five-membered ring.35b With a σ-co-
ordinated acetylide ligand in 2a, we were interested in how the
allenyne was activated. Two complexes were thus prepared for
this purpose. The reported preparation6 of 3d is slightly modified
to obtain the vinylidene complex with a terminal triple bond,
{[Ru]dCdCHCPh2CH2CtCH}BF4 (7, [Ru]dCp(PPh3)2Ru).
The acetylide complex with a terminal double bond, [Ru]-
CtCCPh2CH2CHdCH2 (8), was also prepared. Interestingly,
treatment of these two complexes with the same gold catalyst
mentioned above resulted in no reaction. Thus the mechanism of
the gold catalyst could proceed via a π-coordination of either
acetylene or allene in the substrate. Accordingly, the terminal
vinyl moiety of 8 may not coordinate to the Au(PPh3)þ catalyst.
Hence, we suggest that the formation of 6a and 6b proceeds
preferably via π-coordination of the allenyl moiety of the ligand
to the gold catalyst.
General Procedures. All manipulations were performed under
an atmosphere of dry nitrogen using vacuum-line, drybox, and
standard Schlenk techniques. Solvents were dried by standard
methods and distilled under nitrogen before use. All reagents
were obtained from commercial suppliers and used without fur-
ther purification. Complexes [Ru]Cl ([Ru] = Cp(PPh3)2Ru),6,38a
[Ru0]Cl ([Ru0] = Cp(PPh3)(P(OPh)3)Ru),6b Cp(dppe)RuCl,6,38b
[[Ru]dCdCdCPh2][PF6] (1),6 and [[Ru0]dCdCdCPh2][PF6]
(10)6b and its dppe analogue [Cp(dppe)RudCdCdCPh2][PF6]
(100)6a were prepared by literature methods. NMR spectra were
recorded on Bruker Avance-400 and DMX-500 FT-NMR spectrom-
eters at room temperature unless stated otherwise and were
reported in units of δ with residual protons in the solvent as a
standard (CDCl3, 7.26). Electrospray ionization mass spectrom-
etry, elemental analyses, and X-ray diffraction studies were
carried out at the Regional Center of Analytical Instrument
located at National Taiwan University. All reagents were ob-
tained from commercial suppliers.
Synthesis of 2 and 3. To a flask charged with 1 (291 mg,
0.28 mmol) in THF (25 mL) at -78 °C under nitrogen was added
dropwise the Grignard reagent MgBrCH2CtCCH3 until the
solution become yellow. This solution was continually stirred at
room temperature for 10 min, and the solvent was removed
under rotary evaporation to give the yellow crude precipitates of
the acetylide complexes 2a and 3a (the ratio of 2a and 3a is about
10:1 from the 31P NMR spectrum). This mixture was purified by
column chromatography on an Al2O3-packed column with
hexane/diether ethyl (10:9) as eluent. A yellow band was col-
lected and the solvent was removed to give the major product,
[Ru]-CtCC(Ph)2CMedCdCH2 (2a) (171 mg, in 65% yield). A
mixture of compounds 2a and 3a (51 mg) was also obtained from
the second yellow band for spectroscopic data of 3a. Spectro-
scopic data for 2a are as follows. 1H NMR (CDCl3): δ 7.78-6.85
(m, 40H, Ph), 4.51 (q, JH-H = 2.7 Hz, 2H, dCH2), 4.42 (s, 5H,
Cp), 2.19 (t, JH-H = 2.7 Hz, 3H, CH3). 31P NMR (CDCl3): δ
50.13 (s, PPh3). 13C NMR (C6D6): δ 207.98 (CdCH2),
When the gold-catalyzed cycloaddition reaction of 3d was
carried out using a mixture of CD2Cl2 and D2O as a solvent
under nitrogen, the monodeuterated complex 6d-D, where
the deuteration took place at the olefinic site, was obtained.
1
147.67-125.88 (Ph), 113.94 (Cδ), 107.73 (Cβ), 97.62 (t, JC-P
=
From the H NMR spectrum of 6d-D, one of two olefinic
24.0 Hz, CR), 85.62 (Cp), 75.91 (CdCH2), 57.99 (Cγ), 18.79
(CH3). Mass ESI: m/z 935.2653 (Mþ þ 1). A solid sample with
one diethyl ether molecule trapped in the crystal confirmed by
1H NMR was used for elmental analysis. Anal. Calcd for
C64H60OP2Ru: C, 76.24; H, 6.00. Found: C, 76.46; H, 6.31.
Spectroscopic data for 3a from the mixture of 2a and 3a are as
follows. 1H NMR (CDCl3): δ 7.78-6.85 (m, 40H, Ph), 4.27
(Cp), 3.07 (q, 5JH-H = 2.4 Hz, 2H, CH2), 1.45 (t, 5JH-H = 2.4
Hz, 3H, CH3). 31P NMR (CDCl3): δ 51.20 (s, PPh3). 13C NMR
(C6D6): δ 149.17-125.72 (Ph), 115.25 (Cβ), 85.83 (Cp), 78.86
(CtC), 77.68 (CtC), 52.18 (Cγ), 35.53 (CH2), 3.82 (CH3).
Complexes 2b (R = CH2CH3 in 51% yield) and 2c (R = Ph
in 38% yield) were also prepared using similar procedures.
Spectroscopic data for 2b are as follows. 1H NMR (CDCl3): δ
protons is substituted by deuterium, as evidenced by a 46%
decrease in intensity of the proton signal at δ 5.00. Similarly
the reaction of complex 2b in the presence of D2O also caused
37% deuterium substitution as determined from the intensity
decrease of the unique olefinic proton signal at δ 5.31 of 6b.
These results support the formation from 3d to 6d via the
hydration substitution.
In summary, we report the synthesis of three acetylide
complexes, 2a-2c, each tethering a terminal allenyl group.
(35) (a) Cheong, P. H. Y.; Morganelli, P.; Luzung, M. R.; Houk,
K. N.; Toste, F. D. J. Am. Chem. Soc. 2008, 130, 4517–4526. (b) Yang,
C. Y.; Lin, G. Y.; Liao, H. Y.; Swarup, D.; Liu, R. S. J. Org. Chem. 2008, 73,
4907–4914.
(36) Zhang, Z.; Liu, C.; Kinder, R. E.; Han, X.; Qian, H.; Widenhoefer,
R. A. J. Am. Chem. Soc. 2006, 128, 9066–9073.
(37) Nieto-Oberhuber, C.; Lopez, S.; Echavarren, A. M. J. Am.
Chem. Soc. 2005, 127, 6178–6179.
(38) (a) Bruce, M. I.; Windsor, N. J. Aust. J. Chem. 1977, 30, 1601–
1604. (b) Ashby, G. S.; Bruce, M. I.; Tomkins, I. B.; Wallis, R. C. Aust. J.
Chem. 1979, 32, 1003–1016.
ꢁ

Article
Organometallics, Vol. 29, No. 24, 2010 6835
7.39-6.96 (m, 40H, Ph), 4.48 (t, JH-H = 3.6 Hz, 2H, dCH2),
4.29 (s, 5H, Cp), 2.18 (m, 2H, CH2), 0.95 (t, JH-H = 7.4 Hz, 3H,
CH3). 31P NMR (CDCl3): δ 50.36 (s, PPh3). 13C NMR (CDCl3):
δ 206.47 (CdCH2), 147.37-125.26 (Ph), 114.30 (Cδ), 113.21
(Cβ), 97.02 (t, JC-P = 24.1 Hz, CR), 85.13 (Cp), 78.08 (CdCH2),
57.30 (Cγ), 22.85 (CH2), 12.62 (CH3). Mass ESI: m/z 949.2762
(Mþ þ 1), 732.1670 ([Ru] þ CH3CN). A solid sample with one
diethyl ether molecule trapped in the crystal, confirmed by
NMR, was used for elmental analysis. Anal. Calcd for C65H62O-
P2Ru: C, 76.37; H, 6.11. Found: C, 76.20; H, 6.04. Spectroscopic
data for 2c are as follows. 1H NMR (CDCl3): δ 7.82-6.96 (m,
40H, Ph), 4.67 (s, 2H, CdCH2), 4.04 (s, 5H, Cp). 31P NMR
(CDCl3): δ 50.47 (s, PPh3). 13C NMR (CDCl3): δ 210.22
(CdCH2), 147.58-125.33 (Ph), 114.31 (Cδ), 113.52 (Cβ),
99.02 (t, JC-P = 24.0 Hz, CR), 85.05 (Cp), 78.83 (CdCH2),
55.55 (Cγ). Mass ESI: m/z 997.2697 (Mþ þ 1), 732.1560 ([Ru] þ
CH3CN). We used NMR spectra to identify complexes 3b and
3c from the corresponding mixtures. Spectroscopic data for 3b
from HSQC), 6.51 (s, 1H, CdCH2), 5.83 (s, 1H, CdCH2), 4.76
(s, 5H, Cp), 1.73 (CH3). 31P NMR (CDCl3): δ 46.03, 45.50 (2 d,
AB, JP-P = 28.9 Hz, 2 PPh3). 13C NMR (CDCl3): δ 289.27
(t, JC-P = 11.5 Hz, CR), 176.64 (CdCH2), 164.70 (dCPh),
156.15 (t, JC-P = 6.9 Hz, Cβ), 143.04-127.04 (Ph), 125.99
(dCH2), 125.79 (Ph), 92.95 (Cp), 60.12 (PhC), 23.69 (CH3).
Mass ESI: m/z 935.2643 (Mþ), 732.1595 ([Ru] þ CH3CN). Anal.
Calcd for C60H51BF4P2Ru: C, 70.52; H, 5.03. Found: C, 70.29;
H, 5.21. Complexes 5b (in 88% yield) and 5c (in 85% yield) were
1
also prepared using similar procedures. The H and 31P NMR
data of the slightly more stable intermediate 4b, obtained from
protonation using CF3COOH, was collected. Spectroscopic
1
data for 4b are as follows. H NMR (CDCl3): δ 7.44-6.80 (m,
40H, Ph), 4.96 (t, 2H, JH-H = 3.3 Hz, dCH2), 4.77 (s, 5H, Cp),
4.75 (t, 1H, JH-H = 3.3 Hz, dCH), 1.58 (m, 2H, CH2), 0.89
(t, 3H, JH-H = 7.3 Hz, CH3). 31P NMR (CDCl3): δ 41.78
1
(s, PPh3). Spectroscopic data for 5b are as follows. H NMR
(CDCl3): δ 7.70 (s, 1H, dCH), 7.46-6.75 (m, 40H, Ph), 6.34 (s,
1H, dCH2), 5.87 (s, 1H, dCH2), 4.76 (s, 5H, Cp), 2.61 (m, 1H,
1
are as follows. H NMR (CDCl3): δ 4.31 (Cp), 3.11 (br, 2H,
CH2), 1.94 (m, 2H, CH2CH3), 0.96 (t, 3H, CH3 overlapped with
CH2), 2.24 (m, 1H, CH2), 0.33 (t, 3H, JH-H = 7.1 Hz, CH3). 31
P
that of 2b). 31P NMR (CDCl3): δ 51.13 (s, PPh3). 13C NMR
NMR (CDCl3): δ 45.51, 43.89 (2 d, JP-P = 30.0 Hz, 2 PPh3). 13
C
(CDCl3): δ 148.46-125.25 (Ph), 114.42 (Cβ), 97.67 (t, JC-P
=
NMR (CDCl3): δ 292.68 (t, JC-P = 10.5 Hz, CR), 173.51
(CdCH2), 163.26 (dCPh), 159.29 (t, JC-P = 6.4 Hz, Cβ),
143.36-125.69 (Ph), 125.65 (CdCH2), 92.57 (Cp), 64.25
(PhC), 28.75 (CH2), 8.96 (CH3). Mass ESI: m/z 949.2697
(Mþ). Anal. Calcd for C61H53BF4P2Ru: C, 70.73; H, 5.16.
Found: C, 70.57; H, 5.45. Spectroscopic data for 5c are as
follows. 1H NMR (CDCl3): δ 7.47-6.77 (m, 40H, Ph), 6.13
(s, 1H, dCH2), 5.80 (s, 1H, dCH2), 4.70 (s, 5H, Cp). 31P NMR
(CDCl3): δ 45.80 (s, PPh3).
24.5 Hz, CR), 85.29 (Cp), 83.72 (tC), 78.53 (tC), 51.40 (Cγ),
34.78 (CH2), 19.90 (CH3), 12.04 (CH2). Spectroscopic data for
3c are as follows. 1H NMR (CDCl3): δ 7.81-6.95 (m, 40H, Ph),
4.25 (s, 5H, Cp), 3.34 (s, 2H, CH2). 31P NMR (CDCl3): δ 51.33
(s, PPh3). 13C NMR (CDCl3): δ 148.25-125.37 (Ph), 114.20
(Cβ), 99.01 (t, JC-P = 21.3 Hz, CR), 89.97 (tC), 85.28 (Cp),
78.84 (tC), 51.52 (Cγ), 35.42 (CH2).
Synthesis of 20 and 30. Mixtures of complexes 2a0/3a0 and 2b0/
3b0 were also prepared from 10 using similar procedures. Spec-
troscopic data for 2a0 are as follows. 1H NMR (CDCl3): δ
7.73-6.80 (m, 40H, Ph), 4.37 (s, 5H, Cp), 4.33 (q, JHH = 2.7
Hz, 2H, dCH2), 1.83 (t, JHH = 2.7 Hz, 3H, CH3). 31P NMR
Reactions of 2a0 and 2b0. Reaction of 2a0 with HBF4 was
similarly carried out using the procedure for 5a. A mixture of the
crude product contained 5a0 in ca. 65% yield by NMR. Complex
5a0 is not stable for purification; only 31P NMR spectroscopic
data were obtained. With two stereogenic centers, two diaste-
reomers are expected. 31P NMR (CDCl3): δ 135.41, 51.87 (2 d,
(CDCl3): δ 139.31 (d, JP-P = 67.1 Hz, P(OPh)3), 53.02 (d, JP-P
=
1
67.1 Hz, PPh3). Spectroscopic data for 2b0 are as follows. H
NMR (CDCl3): δ 7.72-6.78 (m, 40H, Ph), 4.44 (br, 2H, dCH2),
4.36 (s, 5H, Cp), 2.22 (m, 1H, CH2), 2.07 (m, 1H, CH2), 0.83
(t, JH-H = 7.3 Hz, 3H, CH3). 31P NMR (CDCl3): δ 139.07 (d,
JP-P = 55.1 Hz, P(OPh)3, PPh3); 134.97, 49.28 (2 d, JP-P
=
55.3 Hz, P(OPh)3, PPh3) with a ratio of 1:1. Similarly complex
5b0 in 76% NMR yield was obtained from 2b0. 31P NMR
(CDCl3): δ 132.28, 51.34 (2 d, JP-P = 54.2 Hz, P(OPh)3, PPh3);
125.03, 47.02 (2 d, JP-P = 54.2 Hz, P(OPh)3, PPh3) with a ratio
of 1:1.
J
P-P = 67.0 Hz, P(OPh)3), 52.81 (d, Jp-p = 67.0 Hz, PPh3). 13
C
NMR (CDCl3): δ 206.44 (CdCH2), 152.02-121.77 (Ph), 114.67
(Cδ), 110.83 (Cβ), 84.47 (Cp), 77.88 (CdCH2), 57.20 (Cγ), 22.48
(CH2), 12.45 (CH3). Spectroscopic data for 3a0 are as follows. 1H
NMR (CDCl3): δ 7.63-6.82 (m, 40H, Ph), 4.35 (s, 5H, Cp), 2.99
Synthesis of 6d. A flask was charged with AgSbPF6 (1.87 mg,
0.05 mmol) and AuPPh3Cl (2.69 mg, 0.05 mmol) in wet CH2Cl2
(a small amount of H2O in 1.22 mL of CH2Cl2) under nitrogen,
and the solution was stirred at room temperature for 10 min.
The other flask was charged with complex 3d (0.10 g, 0.11 mmol)
in CH2Cl2 (a small amount of H2O in 1.33 mL of CH2Cl2) under
nitrogen; then the latter solution was added into the former one.
The solution was stirred at room temperature for 1.5 h, and then
the solution was filtered through a sintered glass with Celite. The
solid was dissolved with 10 mL of CH2Cl2, and then the solvent
was reduced to about 3 mL under rotary evaporation and 30 mL
of diethyl ether was added to cause precipitation. The precipi-
tates were filtered and washed with diethyl ether/hexane and
dried under vacuum to give 6d (110.6 mg, yield 88%). Spectro-
scopic data for 6d are as follows. 1H NMR (CDCl3): δ 7.65-6.85
(m, 40H, Ph), 5.77 (m, 1H, dCH), 5.00 (m, 1H, dCH), 4.67
(s, 5H, Cp), 3.37 (br, 2H, CH2). 31P NMR (CDCl3): δ 41.09
(s, PPh3). 13C NMR (CDCl3): δ 372.91 (t, JC-P = 15.2 Hz, CR),
142.65 (Cβ), 137.79-125.22 (Ph), 123.97 (dC), 119.38 (Cd),
94.00 (Cp), 61.41 (Cγ), 57.83 (CH2). Mass ESI: m/z 921.05 (Mþ).
Anal. Calcd for C59H49F6P2RuSb: C, 61.26; H, 4.27. Found: C,
61.04; H, 4.26.
5
(q, JH-H = 2.2 Hz, 2H, CH2), 1.53 (t, JH-H = 2.2 Hz, 3H,
CH3). 31P NMR (CDCl3): δ 140.26 (d, JP-P = 65.8 Hz,
P(OPh)3), δ 53.52 (d, JP-P = 65.8 Hz, PPh3). Spectroscopic
data for 3b0 are as follows. 1H NMR (CDCl3): δ 7.72-6.78
(m, 40H, Ph), 4.35 (s, 5H, Cp), 2.99 (br, 2H, CH2), 2.06 (m, 2H,
CH2), 0.96 (t, JH-H = 7.4 Hz, 3H, CH3). 31P NMR (CDCl3):
δ 140.01 (d, JP-P = 66.7 Hz, P(OPh)3), 53.35 (d, JP-P = 66.7 Hz,
PPh3). 13C NMR (CDCl3): δ 152.14-121.68 (Ph), 112.46 (Cβ),
84.74 (Cp), 83.50 (CtC), 78.57 (CtC), 51.38 (Cγ), 34.79 (CH2),
14.05 (CH3), 12.58 (CH2).
Synthesis of 5a. To a flask charged with 2a (71.1 mg, 0.07 mmol)
in diethyl ether (30 mL) at -78 °C under nitrogen was added
dropwise HBF4 (54% in Et2O) to cause the formation of
pink precipitates. The addition of HBF4 was continued until no
pink solid is further formed. The pink precipitates were filtered
and washed with hexane to give presumably the vinylidene
intermediate 4a. This precipitates were dried under vacuum,
and then the dried product was dissolved in CHCl3 and the
solution was stirred at room temperature for 3 h under nitrogen,
becoming dark red. No attempt was made to collect spectro-
scopic data of 4a. The solvent was removed, and CH2Cl2 (3 mL)
and hexane (40 mL) were sequentially added to cause formation
of dark red precipitates, which were filtered and washed with
hexane and then dried under vacuum to afford 5a (70.3 mg, 91%
yield). Spectroscopic data for 5a are as follows. 1H NMR
(CDCl3): δ 7.73-6.67 (m, 40H, Ph), 7.25 (s, 1H, dCH observed
Complexes 6a and 6b were also prepared from 2a and 2b,
respectively, using similar procedures. Spectroscopic data for 6a
1
(in 87% yield) are as follows. H NMR (CDCl3): δ 7.51-6.86
(m, 40H, Ph), 5.22 (q, JH-H = 1.3 Hz, 1H, CH), 4.53 (s, 5H,
4
Cp), 3.79 (br, 2H, CH2), 1.33 (t, 4JH-H = 1.3 Hz, 3H, CH3). 31
P
NMR (CDCl3): δ 41.59 (s, PPh3). 13C NMR (CDCl3): δ 357.75

6836 Organometallics, Vol. 29, No. 24, 2010
Chen et al.
(t, JC-P = 16.2 Hz, CR), 144.12 (Cβ), 143.88-126.95 (Ph),
121.76 (HCd), 93.30 (Cp), 69.65 (Cγ), 34.43 (CH2), 13.12
(CH3). Mass ESI: m/z 935.2519 (Mþ). Anal. Calcd C60H51-
F6P2RuSb: C, 61.55; H, 4.39. Found: C, 61.61; H, 4.50. Spectro-
scopic data for 6b (in 85% yield) are as follows. 1H NMR
(CDCl3): δ 7.44-6.88 (m, 40H, Ph), 5.31 (s, 1H, CH), 4.62
(s, 5H, Cp), 3.89 (br, 2H, CH2), 1.59 (m, 2H, CH2), 0.93 (t, 3H,
J = 7.2 Hz, CH3). 31P NMR (CDCl3): δ 41.02 (s, PPh3). 13C
NMR (CDCl3): δ 356.96 (t, JC-P = 16.0 Hz, CR), 150.44 (Cβ),
144.30-126.92 (Ph), 119.22 (HCd), 93.41 (Cp), 69.96 (Cγ),
34.74 (CH2), 19.86 (CH2), 11.99 (CH3). Mass ESI: m/z
949.2667 (Mþ). Anal. Calcd for C61H53F6P2RuSb: C, 61.84;
H, 4.51. Found: C, 61.63; H, 4.33.
using 3 kW sealed-tube molybdenum KR radiation. Exposure
time was 5 s per frame. Multiscan absorption correction was
applied, and decay was negligible. Data were processed, and the
structures were solved and refined by the SHELXTL program.39
The structure was solved using direct methods and confirmed by
Patterson methods refining on intensities of all data (35 888
reflections) to give R1 = 0.0310 and wR2 = 0.0688 for 10 768
unique observed reflections (I > 2σ(I)). Hydrogen atoms were
placed geometrically using the riding model with thermal param-
eters set to 1.2 times that for the atoms to which the hydrogen
is attached and 1.5 times that for the methyl hydrogen. Solid-
state structure determinations were similarly carried out for 5b
and 6d.
Single-Crystal X-ray Diffraction Analysis of 2b, 5b, and 6d.
Single crystals suitable for X-ray diffraction study were grown
via slow diffusion of diethyl ether into a CH2Cl2 solution of 2b at
room temperature. A single crystal of dimensions 0.25 ꢀ 0.15 ꢀ
0.10 mm3 was glued to a glass fiber and mounted on a Nonius
Kappa CCD diffractometer. The diffraction data were collected
Acknowledgment. This research is supported by the
National Science Council and National Center of High-
Performance Computing of Taiwan, Republic of China.
Supporting Information Available: CIF files giving crystal-
lographic data for complexes 2b, 5b, and 6d. This material is
available free of charge via the Internet at http://pubs.acs.org.
(39) SHELXTL: Structure Analysis Program, version 5.04; Siemens
Industrial Automation Inc.: Madison, WI, 1995.