8206
Acknowledgements
Financial support from Conselho Nacional de Pesquisa e Desenvolvimento (CNPq–Brazilian
Agency) is acknowledged. T.M.C. thanks CNPq for a fellowship, E.A.N. for a scholarship.
M.N. thanks CAPES/COFECUB for a travel grant. Professor H. Uzar, Siegen University,
Germany is acknowledged for a gift of 6-bromopicoline. We are also very grateful to Professors
J.-Y. Ne´de´lec and E. Leonel, CNRS-Thiais, France for useful and helpful tips and discussion.
References
1. Reedijk, J. In Comprehensive Coordination Chemistry, Wilkinson, G., Ed.; Pergamon, Oxford, 1987; Vol. 2, p. 73;
see also leading citations in Ref. 5d.
2. Newkome, G. R.; Kiefer, G. E.; Kohli, D. K.; Xia, Y.-J.; Fronczek, F. R.; Baker, G. R. J. Org. Chem. 1989, 54,
5105; Du¨rr, H.; Zengerle, K.; Trierweiler, H.-P. Z. Naturforsch. 1988, 43b, 361; Mukkala, V.-M.; Kwiatkowski,
M.; Kankare, J.; Takalo, H. Helv. Chim. Acta 1993, 76, 893; Harding, M. M.; Koert, U.; Lehn, J.-M.;
Marquis-Rigault, A.; Piguet, C.; Siegel, J. Helv. Chim. Acta 1991, 74, 594; Echegoyen, L.; DeCian, A.; Fischer,
J.; Lehn, J.-M. Angew. Chem., Int. Ed. Engl. 1991, 30, 828.
3. Rodriguez-Ubis, J.-C.; Alpha, B.; Plancherel, D.; Lehn, J.-M. Helv. Chim. Acta 1984, 67, 2264.
4. Newkome, G. R.; Puckett, W. E.; Kiefer, G. E.; Gupta, V. K.; Xia, Y.; Coreil, M.; Hackney, M. A. J. Org. Chem.
1982, 47, 4116.
5. (a) 65% from 6-chloropicoline with n-BuLi/SOCl2: Oae, S.; Inibushi, Y.; Yoshihara, M. Phosphorous, Sulfur Silicon
1995, 103, 101; (b) 45–50% from 6-bromopicoline with NaOOCH/Pd–C/aq NaOH in phase transfer conditions:
Newkome, G. R.; Pantaleo, D. C.; Puckett, W. E.; Ziefle, P. L.; Deutsch, W. A. J. Inorg. Nucl. Chem. 1981, 43,
1529; Kauffmann, Th.; Ko¨nig, J.; Woltermann, A. Chem. Ber. 1976, 109, 3864; Bamfield, P.; Quam, P. M. Synthesis
1978, 537; (c) 40% from 2-picoline/2-picoline-N-oxide in phase transfer conditions: Haginiwa, J.; Higuchi, Y.
Yakugaku Zasshi 1973, 93, 144; (d) 73% from 6-bromopicoline with t-BuOH/NaH/Ni(OAc)2/PPh3: Fort, Y.; Becker,
S.; Caube`re, P. Tetrahedron 1994, 41, 11893; (e) 52% from 2,2%-bipyridine with MeLi/MnO2: Shaul, M.; Cohen,
Y. J. Org. Chem. 1999, 64, 9358; Dietrich-Bicheker, C. O.; Marnot, P. A.; Sauvage, J.-P. Tetrahedron Lett. 1982,
23, 5291; (f) 50% from 6,6%-dibromo-2,2%-bipyridine with BuLi/Me2SO4: Parks, J. E.; Wagner, B. E.; Holm, R. H.
J. Organometal. Chem. 1973, 56, 53; (g) 22% from tris(6-methyl-2-pyridyl)phosphine with Br2/MeOH: Uchida, Y.;
Kajita, R.; Kawasaki, Y.; Oae, S. Tetrahedron Lett. 1995, 36, 4007; (h) 53% from 2-ethylsulfinyl-6-methylpyridine
and MeMgBr: Uenishi, J.; Tanaka, T.; Wakabayashi, S.; Oae, S. Tetrahedron Lett. 1990, 31, 4625; (i) <1% from
6-aminopicoline: DeTar, D. R. Org. React. 1957, 9, 409; (j) 1% from 2-picoline with Pd–C: Fabian, R. H.; Klassen,
D. M.; Sonntag, R. W. Inorg. Chem. 1980, 19, 1977; (k) 65% from Br-pic/Ra–Ni: Rode, T.; Breitmaier, E. Synthesis
1987, 574.
6. (a) Tiecco, M.; Testaferri, L.; Tingoli, M.; Chianelli, D.; Montanucci, M. Synthesis 1984, 736; (b) Iyoda, M.; Otsuka,
H.; Sato, K.; Nisato, N.; Oda, M. Bull. Chem. Soc. Jpn. 1990, 63, 80.
7. Hassan, J.; Pennlva, V.; Lavenot, L.; Gozzi, Ch.; Lemaire, M. Tetrahedron 1998, 54, 13793.
8. Durandetti, M.; Ne´de´lec, J.-Y.; Pe´richon, J. J. Org. Chem. 1996, 61, 1748.
9. Gosmini, C.; Ne´de´lec, J.-Y.; Pe´richon, J. Tetrahedron Lett. 1997, 38, 1941.
10. Gosmini, C.; Ne´de´lec, J.-Y.; Pe´richon, J. Tetrahedron Lett. 2000, 41, 201.
11. (a) Gosmini, C.; Lasry, S.; Ne´de´lec, J.-Y.; Pe´richon, J. Tetrahedron 1998, 54, 1289; (b) Gosmini, C.; Ne´de´lec, J.-Y.;
Pe´richon, J. Tetrahedron Lett. 2000, 41, 5039.
12. The inclusion of the preparation of Br-pic from 6-aminopicoline5b on a 100 gram scale in an undergraduate practical
course attests to its reliability — Professor H. Uzar, Universita¨t Siegen, Germany, private communication.
13. In order to obtain best yields, it is advisable to clean the nickel foam before use by immersion in 6 M HCl for
10 min followed by sequential sonication in water and ethanol (10 min each) and drying in a desiccator.
14. Where dmbp (2) is not available, bpy (1) can be used with equal success. It is preferable to use 2 as a ligand in
the catalytic species in as much as it avoids contamination of the product, which, in the former case can be used
without recrystallisation.
15. It is best to monitor the current in such a way as to maintain the potential at ]−1.55 V in order to avoid reduction
of Br-pic. In doing this, the current drops periodically to about 80 mA, slowly returning however to its original
value.