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Organometallics 2009, 28, 1138–1142
Remarkable Effect of Halogens on Catalytic Activities of
Thiolato-Bridged Diruthenium Complexes in Propargylic
Substitution Reactions
Yoshiaki Tanabe, Keiichiro Kanao, Yoshihiro Miyake, and Yoshiaki Nishibayashi*
Institute of Engineering InnoVation, School of Engineering, The UniVersity of Tokyo, Yayoi, Bunkyo-ku,
Tokyo 113-8656, Japan
ReceiVed NoVember 21, 2008
Thiolato-bridged dibromo- and diiododiruthenium complexes [{Cp*RuX(µ-SR)}2] (X ) Br, I; R )
Me, iPr) have been prepared and characterized by X-ray analysis. Examination of their catalytic activity
in propargylic substitution reactions of 1-phenyl-2-propyn-1-ol with some nucleophiles has revealed that
the complexes [{Cp*RuX(µ-SiPr)}2] (X ) Br, I) work as catalysts but less effectively in comparison
with the well-investigated dichloride analogue [{Cp*RuCl(µ-SiPr)}2].
transfer between two ruthenium atoms (synergistic effect) is one
of the key factors for the catalytic reactions.6,7 On the other
hand, the catalytic activity of analogous thiolato-bridged diru-
thenium complexes having other halide ligands than chloride
such as bromide and iodide [{Cp*RuX(µ-SR)}2] (X ) Br, I)
has not yet been investigated, although halide ligands coordi-
nated to the ruthenium atoms are expected to affect the electronic
properties of the diruthenium core as well as the formation of
the cationic allenylidene complex which is generated by removal
of halogen atoms from the ruthenium atom and by subsequent
coordination of a propargylic alcohol to it. As an extension of
our chemistry, we have now prepared a series of thiolato-bridged
dibromo- and diiododiruthenium complexes [{Cp*RuX(µ-
Introduction
We have previously demonstrated that thiolato-bridged
dichlorodiruthenium complexes [Cp*RuCl(µ-SR)]2 (R ) Me
(1a), Pr (1b), etc; Cp* ) η5- C5Me5) efficiently catalyze
i
propargylic substitution reactions of propargylic alcohols with
a variety of carbon- and heteroatom-centered nucleophiles to
afford the corresponding functionalized propargylic compounds
(Scheme 1).1 Furthermore, we have developed some enantiose-
lective versions of these catalytic reactions.1,2 Stoichiometric
and theoretical studies have revealed that the cationic alle-
nylidene species (A) generated by the reaction of the thiolato-
bridged dichlorodiruthenium complex with a propargylic alcohol
is an actual intermediate and the propargylic substitution reaction
proceeds via nucleophilic attack of a nucleophile on the
electrophilic Cγ atom of this species.3-5
i
SR)}2] (2a: R ) Me, X ) Br; 2b: R ) Pr, X ) Br; 3a: R )
Me, X ) I; 3b: R ) iPr, X ) I) (Chart 1) and investigated their
catalytic activity in propargylic substitution reactions.
Investigation on the catalytic reactivity of a series of
chalogenolato-bridged diruthenium complexes [{Cp*RuCl(µ-
YR)}2] (Y ) S, Se, Te), where electronic properties of two
ruthenium atoms are modulated directly by the bridging
chalcogen atoms, has also suggested that the possible charge
(4) For recent examples of catalytic reactions via allenylidene complexes
as key intermediates by our groups, see: (a) Fukamizu, K.; Miyake, Y.;
Nishibayashi, Y. J. Am. Chem. Soc. 2008, 130, 10498. (b) Yada, Y.; Miyake,
Y.; Nishibayashi, Y. Organometallics 2008, 27, 3614. (c) Daini, M.;
Yoshikawa, M.; Inada, Y.; Uemura, S.; Sakata, K.; Kanao, K.; Miyake,
Y.; Nishibayashi, Y. Organometallics 2008, 27, 2046. (d) Yamauchi, Y.;
Yuki, M.; Tanabe, Y.; Miyake, Y.; Inada, Y.; Uemura, S.; Nishibayashi,
Y. J. Am. Chem. Soc. 2008, 130, 2908. (e) Matsuzawa, H.; Kanao, K.;
Miyake, Y.; Nishibayashi, Y. Org. Lett. 2007, 9, 5561. (f) Matsuzawa, H.;
Miyake, Y.; Nishibayashi, Y. Angew. Chem., Int. Ed. 2007, 46, 6488. (g)
Yamauchi, Y.; Onodera, G.; Sakata, K.; Yuki, M.; Miyake, Y.; Uemura,
S.; Nishibayashi, Y. J. Am. Chem. Soc. 2007, 129, 5175. (h) Inada, Y.;
Yoshikawa, M.; Milton, M. D.; Nishibayashi, Y.; Uemura, S. Eur. J. Org.
Chem. 2006, 881. (i) Onodera, G.; Nishibayashi, Y.; Uemura, S. Organo-
metallics 2006, 25, 35. (j) Nishibayashi, Y.; Uemura, S. Curr. Org. Chem.
2006, 10, 135, and references therein.
(5) For recent examples of catalytic reactions via allenylidene complexes
as key intermediates, see: (a) Yeh, K.-L.; Liu, B.; Lo, C.-Y.; Huang, H.-L.;
Liu, R.-S. J. Am. Chem. Soc. 2002, 124, 6510. (b) Datta, S.; Chang, C.-L.;
Yeh, K.-L.; Liu, R.-S. J. Am. Chem. Soc. 2003, 125, 9294. (c) Shen, H.-C.;
Su, H.-L.; Hsueh, Y.-C.; Liu, R.-S. Organometallics 2004, 23, 4332. (d)
Cadierno, V.; Garc´ıa-Garrido, S. E.; Gimeno, J. AdV. Synth. Catal. 2006,
348, 101. (e) Liu, R.-S. Synlett 2008, 801, and references therein.
(6) Preparation of a variety of chalcogenolate-bridged diruthenium
complexes including X-ray analysis and their catalytic activity toward the
propargylic substitution reactions, see: (a) Nishibayashi, Y.; Imajima, H.;
Onodera, G.; Hidai, M.; Uemura, S. Organometallics 2004, 23, 26. (b)
Nishibayashi, Y.; Imajima, H.; Onodera, G.; Inada, Y.; Hidai, M.; Uemura,
S. Organometallics 2004, 23, 5100.
* To whom correspondence should be addressed. E-mail: ynishiba@
sogo.t.u-tokyo.ac.jp.
(1) (a) Nishibayashi, Y.; Wakiji, I.; Hidai, M. J. Am. Chem. Soc. 2000,
122, 11019. (b) Nishibayashi, Y.; Wakiji, I.; Ishii, Y.; Uemura, S.; Hidai,
M. J. Am. Chem. Soc. 2001, 123, 3393. (c) Nishibayashi, Y.; Milton, M. D.;
Inada, Y.; Yoshikawa, M.; Wakiji, I.; Hidai, M.; Uemura, S. Chem.-Eur.
J. 2005, 11, 1433. (d) Ammal, S. C.; Yoshikai, N.; Inada, Y.; Nishibayashi,
Y.; Nakamura, E. J. Am. Chem. Soc. 2005, 127, 9428. (e) Inada, Y.;
Nishibayashi, Y.; Uemura, S. Angew. Chem., Int. Ed. 2005, 44, 7715. (f)
Sakata, K.; Miyake, Y.; Nishibayashi, Y. Chem.-Asian J. 2009, 4, 81.
(2) Enantioselective catalytic propargylic substitution reactions have been
recently developed for Cu and Ni catalysts: (a) Detz, R. J.; Delville,
M. M. E.; Hiemstra, H.; van Maarseveen, J. H. Angew. Chem., Int. Ed.
2008, 47, 3777. (b) Hattori, G.; Matsuzawa, H.; Miyake, Y.; Nishibayashi,
Y. Angew. Chem., Int. Ed. 2008, 47, 3781. (c) Smith, S. W.; Fu, G. C.
J. Am. Chem. Soc. 2008, 130, 12645.
(3) For recent reviews, see: (a) Metal Vinylidenes and Allenylidenes in
Catalysis: From ReactiVity to Applications in Synthesis; Bruneau, C.,
Dixneuf, P. H., Eds.; Wiley-VCH: Weinheim, Germany, 2008. (b) Bruneau,
C.; Dixneuf, P. H. Angew. Chem., Int. Ed. 2006, 45, 2176. (c) Selegue,
J. P. Coord. Chem. ReV. 2004, 248, 1543. (d) Winter, R. F.; Za´lisˇ, S. Coord.
Chem. ReV. 2004, 248, 1565. (e) Rigaut, S.; Touchard, D.; Dixneuf, P. H.
Coord. Chem. ReV. 2004, 248, 1585. (f) Bruce, M. I. Coord. Chem. ReV.
2004, 248, 1603. (g) Cadierno, V.; Gamasa, M. P.; Gimeno, J. Coord. Chem.
ReV. 2004, 248, 1627. (h) Cadierno, V.; Gamasa, M. P.; Gimeno, J. Eur.
J. Inorg. Chem. 2001, 571. (i) Bruce, M. I. Chem. ReV. 1998, 98, 2797.
(7) Phosphido-bridged diruthenium complexes also catalyze propargylic
substitution reactions, see: (a) Miyake, Y.; Endo, S.; Nomaguchi, Y.; Yuki,
M.; Nishibayashi, Y. Organometallics 2008, 27, 4017. (b) Miyake, Y.; Endo,
S.; Yuki, M.; Tanabe, Y.; Nishibayashi, Y. Organometallics 2008, 27, 6039.
10.1021/om8011079 CCC: $40.75
2009 American Chemical Society
Publication on Web 01/29/2009