Unusual activation of 1-ethynyl-1-cyclohexanol by [RuCl(η⁵-C₉H₇)(PPh₃)₂]: synthesis and reactivity of the allenylidene derivative [Ru{[double bond, length half m-dash]C[double bond, length half m-dash]C[double bond, length half m-dash]C(C₁₃H₂₀)}(η⁵-C₉H₇)(PPh₃)₂][PF₆]

Abstract

The reaction of [RuCl(η⁵-C₉H₇)(PPh₃)₂] with an excess of 1-ethynyl-1-cyclohexanol and NaPF₆ in refluxing methanol yielded the allenylidene complex [Ru{[double bond, length half m-dash]C[double bond, length half m-dash]C[double bond, length half m-dash]C(C₁₃H₂₀)}(η⁵-C₉H₇)(PPh₃)₂][PF₆] 1 via an unprecedented coupling of two molecules of the propargyl (prop-2-ynyl) alcohol derivative. Complex 1 can also be obtained by reaction of the vinylvinylidene derivative [Ru{[double bond, length half m-dash]C[double bond, length half m-dash]C(H)R}(η⁵-C₉H₇)(PPh₃)₂][PF₆] 2 (R = 1-cyclohexenyl) with 1-ethynyl-1-cyclohexanol or 1-ethynylcyclohexene in refluxing methanol. The behaviour of 2 towards other 1-alkyn-3-ols has been studied but only the replacement of the vinylidene moiety by the propargyl alcohols, via an η¹-vinylidene–η²-alkyne tautomerization process, to generate both vinylvinylidene [Ru{[double bond, length half m-dash]C[double bond, length half m-dash]C(H)R}(η⁵-C₉H₇)(PPh₃)₂][PF₆] (R = 1-cyclopentenyl, 1-cycloheptenyl or 1-cyclooctenyl) or allenylidene [Ru([double bond, length half m-dash]C[double bond, length half m-dash]C[double bond, length half m-dash]CR₂)(η⁵-C₉H₇)(PPh₃)₂][PF₆] (R = Ph or R₂ = 2,2′-biphenyldiyl) complexes along with 1-ethynylcyclohexene was observed. A similar 1,3-enyne elimination also takes place in the reaction of 2 with phenylacetylene or acetonitrile to afford [Ru{[double bond, length half m-dash]C[double bond, length half m-dash]C(H)Ph}(η⁵-C₉H₇)(PPh₃)₂][PF₆] and [Ru(N[triple bond, length half m-dash]CMe)(η⁵-C₉H₇)(PPh₃)₂][PF₆], respectively. On the basis of these observations a mechanism for the formation of 1 is proposed. The allenylidene complex 1 regioselectively reacts with NaR, in THF at –20 °C, to yield the neutral σ-alkynyl derivatives [Ru{C[triple bond, length half m-dash]CC(C₁₃H₂₀)R}(η⁵-C₉H₇)(PPh₃)₂] (R = C[triple bond, length half m-dash]N or OMe). Protonation of the R = CN derivative with HBF₄·Et₂O, in diethyl ether at –20 °C, afforded the cationic vinylidene complex [Ru{[double bond, length half m-dash]C[double bond, length half m-dash]C(H)C(C₁₃H₂₀)C[triple bond, length half m-dash]N}(η⁵-C₉H₇)(PPh₃)₂][BF₄]. In contrast, protonation with R = OMe gives back the starting allenylidene derivative 1.

References

1. For reviews see: A. B. Antonova and A. A. Johansson, Russ. Chem. Rev., 1989, 58, 693; M. I. Bruce, Chem. Rev., 1991, 91, 197; 1998, 98, 2797.
2. For recent references see: (a) Y. Wakatsuki and H. Yamazaki, J. Organomet. Chem., 1995, 500, 349 and refs. therein; (b) G. Albertin, S. Antoniutti, E. Bordignon, F. Cazzaro, S. Ianelli and G. Pelizzi, Organometallics, 1995, 14, 4114; (c) Y. Wang and M. G. Finn, J. Am. Chem. Soc., 1995, 117, 8045; (d) P.-C. Ting, Y.-C. Lin, G.-H. Lee, M.-C. Cheng and Y. Wang, J. Am. Chem. Soc., 1996, 118, 6433; (e) C. Bianchini, P. Innocenti, M. Peruzzini, A. Romerosa and F. Zanobini, Organometallics, 1996, 15, 272; (f) T. Braun, P. Meuer and H. Werner, Organometallics, 1996, 15, 4075; (g) S.-M. Yang, M. C.-W. Chan, K.-K. Cheung, C.-M. Che and S.-M. Peng, Organometallics, 1997, 16, 2819; (h) C. Slugovc, K. Mereiter, R. Schmid and K. Kirchner, J. Am. Chem. Soc., 1998, 120, 6175; (i) G. Jia and C. P. Lau, J. Organomet. Chem., 1998, 565, 37 and refs. therein; (j) C. Slugovc, M. Mauthner, K. Kacetl, K. Mereiter, R. Schmid and K. Kirchner, Chem. Eur. J., 1998, 4, 2043; (k) C. S. Yi and N. Liu, Organometallics, 1998, 17, 3158; (l) D. Huang, M. Oliván, J. C. Huffman, O. Eisenstein and K. G. Caulton, Organometallics, 1998, 17, 4700; (m) Y.-H. Lo, Y.-C. Lin, G.-H. Lee and Y. Wang, Organometallics, 1999, 18, 982; (n) C. Slugovc, K. Mereiter, R. Schmid and K. Kirchner, Organometallics, 1999, 18, 1011.
3. C. Bruneau and P. H. Dixneuf, Acc. Chem. Res., 1999, 32, 311 and refs. therein.
4. J. R. Lomprey and J. P. Selegue, Organometallics, 1993, 12, 616; R. F. Winter and F. M. Hornung, Organometallics, 1997, 16, 4248; M. I. Bruce, P. Hinterding, P. J. Low, B. W. Skelton and A. H. White, J. Chem. Soc., Dalton Trans., 1998, 467; P. Haquette, D. Touchard, L. Toupet and P. Dixneuf, J. Organomet. Chem., 1998, 565, 63; R. F. Winter, Chem. Commun., 1998, 2209; D. Touchard, P. Haquette, A. Daridor, L. Toupet and P. H. Dixneuf, J. Am. Chem. Soc., 1994, 116, 11157; D. Peron, A. Romero and P. H. Dixneuf, Gazz. Chim. Ital., 1994, 124, 497.
5. (a) J. P. Selegue, J. Am. Chem. Soc., 1983, 105, 5921; (b) M. I. Bruce, P. Hinterding, E. R. T. Tiekink, B. W. Skelton and A. H. White, J. Organomet. Chem., 1993, 450, 209; (c) L. P. Barthel-Rosa, K. Maitra, J. Fischer and J. H. Nelson, Organometallics, 1997, 16, 1714; (d) M. A. Jímenez Tenorio, M. Jímenez Tenorio, M. C. Puerta and P. Valerga, Organometallics, 1997, 16, 5528; (e) M. A. Esteruelas, A. V. Gómez, A. M. López, J. Modrego and E. Oñate, Organometallics, 1997, 16, 5826; (f) I. de los Rios, M. Jiménez Tenorio, M. C. Puerta and P. Valerga, J. Organomet. Chem., 1997, 549, 221; (g) M. A. Esteruelas, A. V. Gómez, A. M. López, E. Oñate and N. Ruiz, Organometallics, 1998, 17, 2297; (h) M. A. Esteruelas, A. V. Gómez, A. M. López and E. Oñate, Organometallics, 1998, 17, 3567; (i) M. A. Esteruelas, A. V. Gómez, A. M. López, M. C. Puerta and P. Valerga, Organometallics, 1998, 17, 4959; (j) M. A. Esteruelas, A. V. Gómez, A. M. López, J. Modrego and E. Oñate, Organometallics, 1998, 17, 5434; (k) M. I. Bruce, P. J. Low and E. R. T. Tiekink, J. Organomet. Chem., 1999, 572, 3; (l) B. Buriez, I. A. Burns, A. F. Hill, A. J. P. White, D. J. Williams and J. D. E. T. Wilton-Ely, Organometallics, 1999, 18, 1504; (m) C. Bianchini, M. Peruzzini, F. Zanobini, C. Lopez, I. de los Rios and A. Romerosa, Chem. Commun., 1999, 443; (n) M. A. Esteruelas, A. V. Gómez, A. M. López, E. Oñate and N. Ruiz, Organometallics, 1999, 18, 1606; (o) B. Buriez, D. J. Cook, K. J. Harlow, A. F. Hill, T. Welton, A. J. P. White, D. J. Williams and J. D. E. T. Wilton-Ely, J. Organomet. Chem., 1999, 578, 264.
6. A. Fürstner, M. Picquet, C. Bruneau and P. H. Dixneuf, Chem. Commun., 1998, 1315; M. Picquet, C. Bruneau and P. H. Dixneuf, Chem. Commun., 1998, 2249; M. Picquet, D. Touchard, C. Bruneau and P. H. Dixneuf, New J. Chem., 1999, 141; A. Fürstner, A. F. Hill, M. Liebl and J. D. E. T. Wilton-Ely, Chem. Commun., 1999, 601; B. M. Trost and J. A. Flygare, J. Am. Chem. Soc., 1992, 114, 5476.
7. J. P. Selegue, Organometallics, 1982, 1, 217.
8. (a) V. Cadierno, M. P. Gamasa, J. Gimeno, M. González-Cueva, E. Lastra, J. Borge, S. García-Granda and E. Pérez-Carreño, Organometallics, 1996, 15, 2137; (b) M. P. Gamasa, J. Gimeno, C. González-Bernardo, J. Borge and S. García-Granda, Organometallics, 1997, 16, 2483; (c) P. Crochet, B. Demerseman, M. I. Vallejo, M. P. Gamasa, J. Gimeno, J. Borge and S. García-Granda, Organometallics, 1997, 16, 5406.
9. V. Cadierno, M. P. Gamasa, J. Gimeno, J. Borge and S. García-Granda, Organometallics, 1997, 16, 3178.
10. (a) J. P. Selegue, B. A. Young and S. L. Logan, Organometallics, 1991, 10, 1972; (b) D. Touchard, N. Pirio and P. H. Dixneuf, Organometallics, 1995, 14, 4920; (c) M. A. Esteruelas, A. V. Gómez, F. J. Lahoz, A. M. López, E. Oñate and L. A. Oro, Organometallics, 1996, 15, 3423.
11. V. Cadierno, M. P. Gamasa, J. Gimeno, E. Lastra, J. Borge and S. García-Granda, Organometallics, 1994, 13, 745.
12. V. Cadierno, M. P. Gamasa, J. Gimeno, M. C. López-González, J. Borge and S. García-Granda, Organometallics, 1997, 16, 4453.
13. D. Touchard and P. H. Dixneuf, Coord. Chem. Rev., 1998, 178–180, 409 and refs. therein.
14. P. Nombel, N. Lugan and R. Mathieu, J. Organomet. Chem., 1995, 503, C22; C. Slugovc, V. N. Sapunov, P. Wiede, K. Mereiter, R. Schmid and K. Kirchner, J. Chem. Soc., Dalton Trans., 1997, 4209; C. Bianchini, G. Purches, F. Zanobini and M. Peruzzini, Inorg. Chim. Acta, 1998, 272, 1; M. Martín, O. Gevert and H. Werner, J. Chem. Soc., Dalton Trans., 1996, 2275.
15. V. Cadierno, M. P. Gamasa, J. Gimeno, E. Pérez-Carreño and S. García-Granda, Organometallics, 1999, 18, 2821.
16. M. P. Gamasa, J. Gimeno, B. M. Martín-Vaca, J. Borge, S. García-Granda and E. Pérez-Carreño, Organometallics, 1994, 13, 4045.
17. For general reviews see: K. M. Nicholas, Acc. Chem. Res., 1987, 20, 207; W. A. Smit, R. Caple and I. P. Smoliakova, Chem. Rev., 1994, 94, 2359; H. Elamouri and M. Gruselle, Chem. Rev., 1996, 96, 1077; C. Mukai and M. Hanaoka, Synlett, 1996, 11.
18. B. E. R. Schilling, R. Hoffmann and D. L. Lichtenberger, J. Am. Chem. Soc., 1979, 101, 585.
19. V. Cadierno, M. P. Gamasa, J. Gimeno, J. Borge and S. García-Granda, J. Chem. Soc., Chem. Commun., 1994, 2495; V. Cadierno, M. P. Gamasa, J. Gimeno, E. Pérez-Carreño and A. Ienco, Organometallics, 1998, 17, 5216; V. Cadierno, S. Conejero, M. P. Gamasa, J. Gimeno, I. Asselberghs, S. Houbrechts, K. Clays, A. Persoons, J. Borge and S. García-Granda, Organometallics, 1999, 18, 582.
20. L. A. Oro, M. A. Ciriano, M. Campo, C. Foces-Foces and F. H. Cano, J. Organomet. Chem., 1985, 289, 117.