Computational study of the copper-free Sonogashira cross-coupling reaction: shortcuts in the mechanism; pp. 133–140Full article in PDF format | doi: 10.3176/proc.2013.2.07
The sec-butylammonium salt catalysed oxidative addition of phenyl bromide to tris(triphenylphosphane)palladium and reaction of phenylacetylene with cis-Pd(PPh3)2(Ph)Br were modelled using DFT B97D/cc-pVDZ method to study the mechanism of the copper-free Sonogashira cross-coupling reaction. sec-Butylammonium bromide influences the oxidative addition by coordinating with palladium catalyst and the resulting product is trans-Pd(PPh3)2(Ph)Br, not the corresponding cis-compound, which is formed in the absence of salt. The transition-state energy of this oxidative addition mechanism is very close to the previously reported biligated oxidative addition pathway. Reaction of acetylene with cis-Pd(PPh3)2(Ph)Br can lead to either a trans- or a cis-Pd(PPh3)2(CCPh)Ph complex, while only the latter is capable of undergoing reductive elimination.
1. Dieck, H. A. and Heck, F. R. Palladium catalyzed synthesis of aryl, heterocyclic and vinylic acetylene derivatives. J. Organomet. Chem., 1975, 93, 259–263.
2. Cassar, L. Synthesis of aryl- and vinyl-substituted acetylene derivatives by the use of nickel and palladium complexes. J. Organomet. Chem., 1975, 93, 253–257.
3. Sonogashira, K., Tohda, Y., and Hagihara, N. A convenient synthesis of acetylenes: catalytic substitutions of acetylenic hydrogen with bromoalkenes, iodoarenes and bromopyridines. Tetrahedron Lett., 1975, 16, 4467–4470.
4. Chinchilla, R. and Nájera, C. The Sonogashira reaction: a booming methodology in synthetic organic chemistry. Chem. Rev., 2007, 107, 874–922.
5. Komáromi, A., Tolnai, G. L., and Novák, Z. Copper-free Sonogashira coupling in amine–water solvent mixtures. Tetrahedron Lett., 2008, 49, 7294–7298.
6. Chen, L.-P., Hong, S.-G., and Hou, H.-Q. Theoretical study on the mechanism of Sonogashira coupling reaction. Chin. J. Struct. Chem., 2008, 27, 1404–1411.
7. Fairlamb, I. J. S., O’Brien, C. T., Lin, Z., and Lam, K. C. Regioselectivity in the Sonogashira coupling of 4,6-dichloro-2-pyrone. Org. Biomol. Chem., 2006, 4, 1213–1216.
8. Chen, L.-P. and Chen, H.-P. DFT investigation on the mechanism of Pd(0) catalyzed Sonogashira coupling reaction. Chin. J. Struct. Chem., 2011, 30, 1289–1297.
9. Sikk, L., Tammiku-Taul, J., and Burk, P. Computational study of copper-free Sonogashira cross-coupling reaction. Organometallics, 2011, 30, 5656–5664.
10. Sikk, L., Tammiku-Taul, J., Burk, P., and Kotschy, A. Computational study of the Sonogashira cross-coupling reaction in the gas phase and in dichloromethane solution. J. Mol. Mod., 2012, 18, 3025–3033.
11. García-Melchor, M., Pacheco, M. C., Nájera, C., Lledos, A., and Ujaque, G. Mechanistic exploration of the Pd-catalyzed copper-free Sonogashira reaction ACS Catal., 2012, 2, 135–144.
12. Amatore, C. and Pfluger, F. Mechanism of oxidative addition of palladium(0) with aromatic iodides in toluene, monitored at ultramicroelectrodes. Organometallics, 1990, 9, 2276–2282.
13. Besora, M., Gourlaouen, C., Yates, B., and Maseras, F. Phosphine and solvent effects on oxidative addition of CH3Br to Pd(PR3) and Pd(PR3)2 complexes. Dalton Trans., 2011, 42, 11089–11094.
14. Sun, W.-J., Chu, W., Yu, L.-J., and Jiang, C.-F. Ligand size effect on PdLn oxidative addition with aryl bromide: a DFT study. Chin. J. Chem. Phys., 2010, 23, 175–179.
15. Mitchell, E. A., Jessop, P. G., and Baird, M. C. A kinetics study of the oxidative addition of bromobenzene to Pd(PCy3)2 (Cy = cyclohexyl) in a nonpolar medium: the influence on rates of added PCy3 and bromide ion. Organometallics, 2009, 28, 6732–6738.
16. Kozuch, S., Amatore, C., Jutand, A., and Shaik, S. What makes for a good catalytic cycle? A theoretical study of the role of an anionic palladium(0) complex in the cross-coupling of an aryl halide with an anionic nucleophile. Organometallics, 2005, 24, 2319–2330.
17. Gooßen, L. J., Koley, D., Hermann, H., and Thiel, W. The mechanism of the oxidative addition of aryl halides to Pd-catalysts: a DFT investigation. Chem. Commun., 2004, 19, 2141–2143.
18. Amatore, C., Jutand, A, Lemaitre, F., Lucricard, J., Kozuch, S., and Shaik, S. Formation of anionic palladium(0) complexes ligated by the trifluoroacetate ion and their reactivity in oxidative addition. J. Organomet. Chem., 2004, 689, 3728–3734.
19. Amatore, C., Azzabi, M., and Jutand, A. Role and effects of halide ions on the rates and mechanisms of oxidative addition of iodobenzene to low-ligated zerovalent palladium complexes Pd0(PPh3)2. J. Am. Chem. Soc., 1991, 113, 8375–8384.
20. Barrios-Landeros, F., Carrow, B. P., and Hartwig, J. F. Autocatalytic oxidative addition of PhBr to Pd(PtBu3)2 via Pd(PtBu3)2(H)(Br). J. Am. Chem. Soc., 2008, 130, 5842–5843.
21. Casado, A. L. and Espinet, P. On the configuration resulting from oxidative addition of RX to Pd(PPh3)4 and the mechanism of the cis-to-trans isomerization of [PdRX(PPh3)2] complexes (R = aryl, X = halide). Organometallics, 1998, 17, 954–959.
22. Goossen, L. J., Koley, D., Hermann, H. L., and Thiel, W. Mechanistic pathways for oxidative addition of aryl halides to palladium(0) complexes: a DFT study. Organometallics, 2005, 24, 2398–2410.
23. Soheili, A., Albaneze-Walker, J., Murry, J. A., Dormer, P. G., and Hughes, D. L. Efficient and general protocol for the copper-free Sonogashira coupling of aryl bromides at room temperature. Org. Lett., 2003, 5, 4191–4194.
24. Amatore, C., Jutand, A., and Suarez, A. Intimate mechanism of oxidative addition to zerovalent palladium complexes in the presence of halide ions and its relevance to the mechanism of palladium-catalyzed nucleophilic substitutions. J. Am. Chem. Soc., 1993, 115, 9531–9541.
25. Chinchilla, R. and Nájera, C. Recent advances in Sonogashira reactions. Chem. Soc. Rev., 2011, 40, 5084–5121.
26. Ljungdahl, T., Bennur, T., Dallas, A., Emtenäs, H., and Mårtensson, J. Two competing mechanisms for the copper-free Sonogashira cross-coupling reaction. Organometallics, 2008, 27, 2490–2498.
27. Frisch, M. J., Trucks, G. W., Schlegel, H. B., Scuseria, G. E., Robb, M. A., Cheeseman, J. R. et al. Gaussian 09. Gaussian, Inc., Wallingford, CT, 2009.
28. Becke, A. D. Density-functional thermochemistry. V. Systematic optimization of exchange–correlation functionals. J. Chem. Phys., 1997, 107, 8554–8560.
29. Grimme, S. Semiempirical GGA-type density functional constructed with a long-range dispersion correction. J. Comput. Chem., 2006, 27, 1787–1799.
30. Dunning, T. H. Gaussian basis sets for use in correlated molecular calculations. I. The atoms boron through neon and hydrogen. J. Chem. Phys., 1989, 90, 1007–1023.
31. Schuchardt, K. L., Didier, B. T., Elsethagen, T., Sun, L., Gurumoorthi, V., Chase, J., Li, J., and Windus, T. L. Basis set exchange: a community database for computational sciences. J. Chem. Inf. Model., 2007, 47, 1045–1052.
32. Feller, D. The role of databases in support of computational chemistry calculations. J. Comp. Chem., 1996, 17, 1571–1586.
33. Ardura, D., López, R., and Sordo, T. L. Relative Gibbs energies in solution through continuum models: effect of the loss of translational degrees of freedom in bimolecular reactions on Gibbs energy barriers. J. Phys. Chem. B, 2005, 109, 23618–23623.
34. Gonzalez, C. and Schlegel, H. B. An improved algorithm for reaction path following. J. Chem. Phys., 1989, 90, 2154–2161.
35. Gonzalez, C. and Schlegel, H. B. Improved algorithms for reaction path following: higher-order implicit algorithms. J. Chem. Phys., 1991, 95, 5853–5860.
36. Marenich, A. V., Cramer, C. J., and Truhlar, D. G. Universal solvation model based on solute electron density and on a continuum model of the solvent defined by the bulk dielectric constant and atomic surface tensions. J. Phys. Chem. B, 2009, 113, 6378–6396.
37. Cramer, C. J. Essentials of Computational Chemistry: Theories and Models. Wiley, 2003.
38. Fitton, P. and Rick, E. A. The addition of aryl halides to tetrakis (triphenylphosphine) palladium(0). J. Organomet. Chem., 1971, 28, 287–291.
39. Rau, S., Lamm, K., Görls, H., Schöffel, J., and Walther, D. Bi- and trinuclear oxalamidinate complexes of palladium as catalysts in the copper-free Sonogashira reaction and in the Negishi reaction. J. Organomet. Chem., 2004, 689, 3582–3592.
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