R. F. Schumacher et al. / Tetrahedron Letters 49 (2008) 538–542
541
Table 2 (continued)
Entry
R2-ZnCl
Supplementary data
Product 3
Yieldb
(%)
Supplementary data associated with this article can be
16
73c
ZnCl
References and notes
2a
Ph
Se
C4H9
1. (a) Miyaura, N. Cross-Coupling Reactions. A Practical
Guide; Springer: Berlin, 2002; (b) Diederich, F.; Stang, P.
J. Metal-Catalyzed Cross-Coupling Reactions; Wiley-
VCH: Weinheim, 1998.
3p
Cl
2. (a) Negishi, E.; Anastasia, L. Chem. Rev. 2003, 103, 1979;
(b) Negishi, E. In Handbook of Organopalladium Chemis-
try for Organic Synthesis; Wiley and Sons: New York,
2002; Vols. 1 and 2; (c) Li, J. J.; Gribble, G. W. Palladium
in Heterocyclic Chemistry. In Tetrahedron Organic Chem-
istry Series; Pergamon: Amsterdam, 2000; Vol. 20; (d)
Negishi, E.; Hu, Q.; Huang, Z.; Qian, M.; Wang, G.
Aldrichim. Acta 2005, 38, 71–88.
3. (a) Knochel, P.; Singer, R. D. Chem. Rev. 1993, 93, 2117;
(b) Staubitz, A.; Dohle, W.; Knochel, P. Synthesis 2003,
233; (c) Gommermann, N.; Koradin, C.; Knochel, P.
Synthesis 2002, 2143; (d) Knochel, P.; Millot, N.; Rodri-
guez, A. L. Org. React. 2001, 58, 417.
Cl
17
90c
ZnCl
2c
Ph
Se
C4H9
3q
a Reactions were performed in the presence of 1a–c (0.25 mmol), 2a–l
(0.75 mmol), using THF (3 mL) as solvent at room temperature for
24 h.
b The yields are given for isolated products.
c Reaction time 30 h.
4. (a) Zeni, G.; Ludtke, D. S.; Panatieri, R. B.; Braga, A. L.
Chem. Rev. 2006, 106, 1032; (b) Zeni, G.; Braga, A. L.;
Stefani, H. A. Acc. Chem. Res. 2003, 36, 731.
5. Nogueira, C. W.; Zeni, G.; Rocha, J. B. T. Chem. Rev.
2004, 104, 6255.
6. Chemistry and Biology of Naturally-occurring Acetylenes
and Related Compounds; Lain, J., Breteler, H., Arnason,
T., Hansen, L., Eds.; Elsevier: Amsterdam, 1988.
7. (a) Barros, O. S. R.; Favero, A.; Nogueira, C. W.;
Menezes, P. H.; Zeni, G. Tetrahedron Lett. 2006, 47, 2179;
(b) Prediger, P.; Moro, A. V.; Nogueira, C. W.; Savegn-
ago, L.; Rocha, J. B. T.; Zeni, G. J. Org. Chem. 2006, 71,
3786; (c) Barros, O. S. R.; Nogueira, C. W.; Stangherlin,
E. C.; Menezes, P. H.; Zeni, G. J. Org. Chem. 2006, 71,
1552; (d) Zeni, G. Tetrahedron Lett. 2005, 46, 2647; (e)
Panatieri, R. B.; Reis, J. S.; Borges, L. P.; Nogueira, C.
W.; Zeni, G. Synlett 2006, 18, 3161.
compounds in view of the usefulness in the organic syn-
thesis, including in the synthesis of natural products.11
Thus, 3-alkynylselenophene 3r was reacted with NaOH
in toluene under reflux for 4 h. Then the terminal alkyne
generated in situ reacts with BuTeTeBu and NaBH4 in
ethanol, under reflux, to give the corresponding vinylic
telluride 4 (Scheme 4).12
In summary, we have explored the Negishi cross-cou-
pling reaction of 3-iodoselenophene derivatives with sev-
eral organozinc compounds in the presence of catalytic
amount of Pd(PPh3)4 under mild reaction conditions
(room temperature) and established a new route to
obtain polyaromatic compounds in good to excellent
yields. Analysis of the 1H and 13C NMR spectra showed
that all the obtained products presented data in full
agreement with their assigned structures.
8. (a) Zeni, G.; Alves, D.; Braga, A. L.; Stefani, H. A.;
Nogueira, C. W. Tetrahedron Lett. 2004, 45, 4823; (b)
Alves, D.; Schumacher, R. F.; Brandao, R.; Nogueira, C.
˜
W.; Zeni, G. Synlett 2006, 7, 1035.
9. Alves, D.; Luchese, C.; Nogueira, C. W.; Zeni, G. J. Org.
Chem. 2007, 72, 6726.
10. General procedure for the cross-coupling reaction. A 10 mL
Schlenk tube, equipped with a magnetic bar, rubber
septum and argon, containing previously prepared the
organozinc compound (0.75 mmol),8 was charged sequen-
tially with the 3-iodoselenophene derivative (0.25 mmol)
and Pd(PPh3)4 (0.0028 g, 0.0025 mmol). The yellow mix-
ture was stirred at room temperature and the reaction time
Acknowledgments
We are grateful to FAPERGS, CAPES (SAUX) and
CNPq for financial support. CNPq are also acknowl-
edged for the fellowships (R.F.S. and G.Z.).
OH
TeBu
1) NaOH, toluene, reflux
2) BuTe)2, NaBH4, EtOH
Ph
Ph
Ph
Ph
Se
Se
3r
4
Scheme 4.