A R T I C L E S
Le Paih et al.
addition10 including enantioselective reaction.11 Intramolecular
addition affords macrocyclic cyclopropenes12 or reactive vinyl
carbenoid species, which can lead to further synthetic transfor-
mations, such as cyclic enones or phenols.13 Conjugated dienes
were obtained by the stoichiometric addition of two molecules
of diazocarbonyl compounds to a cobalt alkyne complex by
O’Connor et al.14
On the other hand, ruthenium-carbene species, designed for
alkene metathesis, are well-known to react with alkynes to
produce vinyl carbene intermediates by intramolecular or
intermolecular ene-yne metathesis,2a,15 ring-closing or cross
metathesis, respectively, leading to the formation of conjugated
dienes.
On the basis of our studies concerning the catalytic activity
of the complex (C5Me5)Ru(cod)Cl9a and its ability to accom-
modate two cis carbene ligands,16a,b we could envisioned the
formation of ruthenium-carbene species, in situ generated from
diazo compounds, and their catalytic addition to alkynes. We
describe here the synthesis of functional and stereodefined
substituted conjugated dienes by the combination of two
molecules of diazo compounds with an alkyne, catalyzed by
the precatalyst (C5Me5)Ru(cod)Cl (eq 1). This selective forma-
tion results from the ruthenium-catalyzed creation of two
carbon-carbon double bonds in a single chemical reaction under
mild conditions.
(8) For review, see (a) Lebel, H.; Marcoux, J. F.; Molinaro, C.; Charette,
A. B. Chem. ReV. 2003, 103, 977–1050. (b) Nishiyama, H. Top.
Organomet. Chem. 2004, 11, 81–92. (c) Maas, G. Chem. Soc. ReV.
2004, 33, 183–190. (d) Sakthivel, A.; Pedro, F. E.; Chiang, A. S. T.;
Ku¨hn, F. E. Synthesis 2006, 1682–1688. (e) Le Maux, P.; Juillard, S.;
Simmoneaux, G. Synthesis 2006, 1701–1704. (f) Uchida, T.; Katsuki,
T. Synthesis 2006, 1715–1723. For recent examples, see: (g) Bon-
naccorsi, C.; Santoro, F.; Gischig, S.; Mezzetti, A. Organometallics
2006, 25, 2002–2010. (h) Huber, D.; Kumar, P. G. A.; Pregosin, P. S.;
Mikhel, I. S.; Mezzetti, A. HelV. Chim. Acta 2006, 89, 1696–1715.
(i) Kim, B. G.; Snapper, M. L. J. Am. Chem. Soc. 2006, 128, 52–53.
(j) Hoang, V. D. M.; Reddy, P. A. N.; Kim, T. J. Tetrahedron Lett.
2007, 48, 8014–8017. (k) Xu, Z.-J.; Fang, R.; Zhao, C.; Huang, J.-S.;
Li, G.-Y.; Zhu, N.; Che, C.-M. J. Am. Chem. Soc. 2009, 131, 4405–
4417.
Results and Discussion
Our initial attempt at transformation9b of phenylacetylene 1a,
in presence of 5 mol % of the precatalyst (C5Me5)RuCl(cod)
(I) (cod ) cycloocta-1,5-diene), with 2.4 equiv of trimethylsi-
lyldiazomethane N2CHSiMe3 (commercial solution at 2 mol L-1
in hexane) in 2 mL of dioxane (conditions A) gave, after 6 h at
60 °C, a 72% yield of disilylated dienes as a mixture of two
isomers 2a and 3a, with a ratio 2a/3a of 30/70 (eq 2). 1H NMR
and NOE experiments showed a Z stereoselectivity for the
trisubstituted double bond, whereas the disubstituted double
bond was formed with a Z/E stereoselectivity (Z/E: 30/70).
(9) (a) De´rien, S.; Dixneuf, P. H. J. Organomet. Chem. 2004, 689, 1382–
¨
1392. (b) Le Paih, J.; De´rien, S.; Ozdemir, I.; Dixneuf, P. H. J. Am.
Chem. Soc. 2000, 122, 7400–7401. (c) Monnier, F.; Castillo, D.;
De´rien, S.; Toupet, L.; Dixneuf, P. H. Angew. Chem., Int. Ed. 2003,
42, 5474–5477. (d) Eckert, M.; Monnier, F.; Shchetnikov, G. T.;
Titanyuk, I. D.; Osipov, S. N.; Toupet, L.; De´rien, S.; Dixneuf, P. H.
Org. Lett. 2005, 7, 3741–3743. (e) Monnier, F.; Vovard-Le Bray, C.;
Castillo, D.; Aubert, V.; De´rien, S.; Dixneuf, P. H.; Toupet, L.; Ienko,
A.; Mealli, C. J. Am. Chem. Soc. 2007, 129, 6037–6049. (f) Vovard-
Le Bray, C.; De´rien, S.; Dixneuf, P. H.; Murakami, M. Synlett 2008,
193–196.
(10) (a) Petiniot, N.; Anciaux, A. J.; Noels, A. F.; Hubert, A. J.; Teyssie´,
P. Tetrahedron Lett. 1978, 19, 1239–1242. (b) Dowd, P.; Garner, P.;
Schappert, R.; Irngartinger, H.; Goldman, A. J. Org. Chem. 1982, 47,
4240–4246. (c) Liao, L.-a.; Zhang, F.; Yan, N.; Golen, J. A.; Fox,
J. M. Tetrahedron 2004, 60, 1803–1816. (d) Panne, P.; Fox, J. M.
J. Am. Chem. Soc. 2007, 129, 22–23. (e) Zhao, L.-B.; Guan, Z.-H.;
Han, Y.; Xie, Y.-X.; He, S.; Liang, Y.-M. J. Org. Chem. 2007, 72,
10276–10278.
Using 2.4 equiv of a commercial solution of N2CHSiMe3 2
mol L-1 in diethyl ether, the same reaction of 1a in dioxane
(conditions B) took place more rapidly, at room temperature
(complete conversion in 30 min). The isolated yield was similar
but the ratio 2a/3a was reversed (85/15 instead of 30/70), the
compound 2a (1Z, 3Z) being now the major product (eq 2).
A study of the reaction conditions was carried out. First the
influence of the reaction temperature and the nature of N2CHSiMe3
solution was studied in 2 mL of dioxane with 1.25 mmol of
phenylacetylene and 2.4 equiv of N2CHSiMe3 (Table 1).
The species N2CHSiMe3 in solution in diethylether was more
reactive than in solution in hexane. After 20 h at room
temperature, only 25% of compounds 2a/3a was produced with
N2CHSiMe3 in hexane whereas 65% yield was obtained after
30 min at room temperature with N2CHSiMe3 in diethylether.
Using both solutions, lower temperature favored the isomer 2a
formation which was almost exclusively obtained, up to 98%
(11) (a) Protopopova, M. N.; Doyle, M. P.; Mu¨ller, P.; Ene, D. J. Am.
Chem. Soc. 1992, 114, 2755–2757. (b) Doyle, M. P.; Protopopova,
M. N.; Mu¨ller, P.; Ene, D.; Shapiro, E. A. J. Am. Chem. Soc. 1994,
116, 8492–8498. (c) Mu¨ller, P.; Imoga¨ı, H. Tetrahedron Asymmetry
1998, 9, 4419–4428. (d) Davies, H. M. L.; Lee, G. H. Org. Lett. 2004,
6, 1233–1236. (e) Lou, Y.; Horikawa, M.; Kloster, R. A.; Hawryluk,
N. A.; Corey, E. J. J. Am. Chem. Soc. 2004, 126, 8916–8918. (f) Lou,
Y.; Remarchuk, T. P.; Corey, E. J. J. Am. Chem. Soc. 2005, 127,
14223–14230. (g) Nowlan, D. T., III; Singleton, D. A. J. Am. Chem.
Soc. 2005, 127, 6190–6191. (h) Weatherhead-Kloster, R. A.; Corey,
E. J. Org. Lett. 2006, 8, 171–174.
(12) (a) Doyle, M. P.; Ene, D. G.; Peterson, C. S.; Lynch, V. Angew. Chem.,
Int. Ed. 1999, 38, 700–702. (b) Doyle, M. P.; Hu, W. Tetrahedron
Lett. 2000, 41, 6265–6269. (c) Doyle, M. P.; Weathers, T. M., Jr.;
Wang, Y. AdV. Synth. Catal. 2006, 348, 2403–2409.
(13) (a) Hoye, T. R.; Dinsmore, C. J.; Johnson, D. S.; Korkowski, P. F. J.
Org. Chem. 1990, 55, 4518–4520. (b) Hoye, T. R.; Dinsmore, C. J.
Tetrahedron Lett. 1991, 32, 3755–3758. (c) Padwa, A.; Austin, D. J.;
Xu, S. L. Tetrahedron Lett. 1991, 32, 4103–4106. (d) Hoye, T. R.;
Dinsmore, C. J. J. Am. Chem. Soc. 1991, 113, 4343–4345. (e) Padwa,
A.; Krumpe, K. E.; Gareau, Y.; Chiacchio, U. J. Org. Chem. 1991,
56, 2523–2530. (f) Padwa, A.; Xu, S. L. J. Am. Chem. Soc. 1992,
114, 5881–5882. (g) Padwa, A.; Austin, D. J.; Xu, S. L. J. Org. Chem.
1992, 57, 1330–1331. (h) Padwa, A.; Krumpe, K. E.; Kassir, J. M. J.
Org. Chem. 1992, 57, 4940–4948. (i) Mu¨ller, P. H.; Kassir, J. M.;
Semones, M. A.; Weingarten, M. D.; Padwa, A. Tetrahedron Lett.
1993, 34, 4285–4288. (j) Padwa, A.; Austin, D. J.; Gareau, Y.; Kassir,
J. M.; Xu, S. L. J. Am. Chem. Soc. 1993, 115, 2637–2647. (k) Padwa,
A.; Kassir, J. M.; Xu, S. L. J. Org. Chem. 1997, 62, 1642–1652.
(14) (a) Hong, P.; Aoki, K.; Yamazaki, H. J. Organomet. Chem. 1978,
150, 279–293. (b) O’Connor, J. M.; Ji, H.; Iranpour, M.; Rheingold,
A. L. J. Am. Chem. Soc. 1993, 115, 1586–1588. (c) O’Connor, J. M.;
Chen, M.-C.; Rheingold, A. L. Tetrahedron Lett. 1997, 38, 5241–
5244. (d) O’Connor, J. M.; Chen, M.-C.; Frohn, M.; Rheingold, A. L.;
Guzei, I. A. Organometallics 1997, 16, 5589–5591.
(15) For review on enyne metathesis, see: (a) Mori, M. Top. Organomet.
Chem. 1998, 1, 133–154. (b) Poulsen, C. S.; Madsen, R. Synthesis
2003, 1–18. (c) Diver, S. T.; Giessert, A. J. Chem. ReV. 2004, 104,
1317–1382. (d) Connon, S. J.; Blechert, S. Top. Organomet. Chem.
2004, 11, 93–124. (e) Diver, S. T. J. Mol. Catal. A 2006, 254, 29–42.
(f) Diver, S. T. Coord. Chem. ReV. 2007, 251, 671–701.
9
7392 J. AM. CHEM. SOC. VOL. 132, NO. 21, 2010