4316
T. Matsumura et al. / Tetrahedron Letters 53 (2012) 4313–4316
10. Red-Al: (a) Choshi, T.; Tonari, A.; Yoshioka, H.; Harada, K.; Sugino, E.; Hibino, S.
J. Org. Chem. 1993, 58, 7952–7954; (b) Yoshioka, H.; Matsuya, Y.; Choshi, T.;
Sugino, E.; Hibino, S. Chem. Pharm. Bull. 1996, 44, 709–714.
11. Hydrazine-Pd/C: Niwas, S.; Chand, P.; Pathak, V. P.; Montgomery, J. A. J. Med.
Chem. 1994, 37, 2477–2480.
12. (a) Yamaguchi, H.; Ishikawa, F. Chem. Pharm. Bull. 1982, 30, 326–332; (b) Ueno,
Y.; Kojima, A.; Okawara, M. Chem. Lett. 1984, 2125–2128; (c) Kawasaki, A. M.;
Wotring, L. L.; Townsend, L. B. J. Med. Chem. 1990, 33, 3170–3176; (d) Seto, S.;
Asano, J. Bioorg. Med. Chem. 2007, 15, 5083–5089; (e) Kikelj, V.; Grosjean, S.;
Meslin, J.-C.; Julienne, K.; Deniaud, D. Synthesis 2010, 2811–2815; (f) Williams,
D. R.; Fu, L. Synlett 2010, 1641–1646.
13. Rousseau, G.; Breit, B. Angew. Chem., Int. Ed. 2011, 50, 2450–2494.
14. Barbero, N.; Martin, R. Org. Lett. 2012, 14, 796–799.
15. Graham, T. H.; Liu, W.; Shen, D.-M. Org. Lett. 2011, 13, 6232–6235.
16. (a) Boukherroub, R.; Chatgilialoglu, C.; Manuel, G. Organometallics 1996, 15,
1508–1510; (b) Ferreri, C.; Costantino, C.; Chatgilaloglu, C.; Boukherroub, R.;
Manuel, G. J. Organomet. Chem. 1998, 554, 135–137.
basically takes place though it proceeds slowly. Hence, we specu-
late that TMSCl could enhance the reaction of TES–Pd(II)–H with
ArSR by some interactions. However, the detailed reaction mecha-
nism including the participation of TMSCl is undetermined at this
stage because further studies are required to propose it.
In summary, a palladium-catalyzed reductive cleavage of alkyl
aryl sulfides affording corresponding arenes has been developed.33
The reaction proceeds smoothly with a catalytic amount of palla-
dium(0) and TESH to afford the corresponding arenes in high yield,
and the reaction is both accelerated and exhibits increased func-
tional group selectivity in the presence of TMSCl. This ligand-free
reaction features mild conditions, easy operation, use of readily
available reagents, and high functional group selectivity. Further
studies on the scope and limitations of this reductive cleavage as
well as the reaction mechanism are in progress and will be re-
ported in due course.
17. No reductive cleavage was observed in the reaction with Ni(COD)2 or RhCl3 for
PdCl2 in THF at room temperature even in the presence of TMSCl.
18. Vuoti, S.; Autio, J.; Laitila, M.; Haukka, M.; Pursiainen, J. Eur. J. Inorg. Chem.
2008, 397–407.
19. Mirza-Aghayan, M.; Boukherroub, R.; Rahimifard, M.; Bolourtchian, M. Appl.
Organomet. Chem. 2010, 24, 477–480.
20. Kar, A.; Sayyed, I. A.; Lo, W. F.; Kaiser, H. M.; Beller, M.; Tse, M. K. Org. Lett.
2007, 9, 3405–3408.
Acknowledgments
21. Gelat, F.; Jayashankaran, J.; Loheir, J.-F.; Gaoumont, A.-C.; Perrio, S. Org. Lett.
2011, 13, 3170–3173.
22. Zhang, Z.; Hu, Z.; Yu, Z.; Chi, H.; Lei, P.; Wang, Y.; He, R. Synth. Commun. 2007,
37, 683–690.
23. González, I. C.; Davis, L. N.; Smith, C. K., II Bioorg. Med. Chem. Lett. 2004, 14,
4037–4043.
This work was financially supported in part by The Grant-in-Aid
for Scientific Research on Innovative Areas ‘Organic Synthesis
based on Reaction Integration’ (No. 2105) and the Global COE pro-
gram ‘Center for Practical Chemical Wisdom’ by MEXT.
24. Singh, G.; Ila, H.; Junjappa, H. Tetrahedron Lett. 1984, 25, 5095–5098.
25. Compounds 7 and 8 were prepared by Suzuki–Miyaura coupling using 3-
methylthiophenylbromide and 4-methoxycarbonylphenylboronic acid with
the corresponding arylboronic acids.
26. Gomes, P.; Gosmini, C.; Nédélec, J.-Y.; Périchon, J. Tetrahedron Lett. 2002, 43,
5901–5903.
References and notes
1. (a) Mozingo, R.; Wolf, D. E.; Harris, S. A.; Folkers, K. J. Am. Chem. Soc. 1943, 65,
1013–1016; (b) Howard, G. A.; Lythgoe, B.; Todd, A. R. J. Chem. Soc. 1945, 556–
561; (c) Shafer, C. M.; Molinski, T. F. J. Org. Chem. 1998, 63, 551–555.
2. Al/HgCl2: Sugimoto, T.; Nishioka, N.; Murata, S.; Matsuura, S. Heterocycles 1987,
26, 2091–2092.
3. Nickel boride: (a) Zumbrunn, A. Synthesis 1998, 1357–1361; (b) Kawasaki, I.;
Sakaguchi, N.; Khadeer, A.; Yamashita, M.; Ohta, S. Tetrahedron 2006, 62,
10182–10192.
4. Cobalt boride: Back, T. G.; Baron, D. L.; Yang, K. J. Org. Chem. 1993, 58, 2407–
2413.
5. Raney copper: Pfleiderer, W. Tetrahedron 1988, 44, 3373–3378.
6. NiCRA/NiCRAL: Becker, S.; Fort, Y.; Vanderesse, R.; Caubère, P. J. Org. Chem.
1989, 54, 4848–4853.
27. Asokan, C. V.; Ila, H.; Junjappa, H. Synthesis 1987, 3, 284–285.
28. Lee, T. R.; Kin, K. J. Heterocycl. Chem. 1989, 26, 747–751.
29. Bethge, L.; Jarikote, D. V.; Seitz, O. Bioorg. Med. Chem. 2008, 16, 114–125.
30. Morton, R. A.; Stubbs, A. L. J. Chem. Soc. 1939, 1321–1324.
31. Corey, J. Y.; Braddock-Wilking, J. Chem. Rev. 1999, 99, 175–292.
32. Yamanoi, Y. J. Org. Chem. 2005, 70, 9607–9609. No silylated products were
obtained in all the reactions reported here.
33. General procedure for the reductive cleavage of alkyl aryl sulfides: To a solution of
aryl alkyl sulfide (0.23 mmol, 1.0 equiv) and PdCl2 (0.007 mmol, 3 mol %,
1.2 mg) in 2 mL of THF was added triethylsilane (amount indicated in Table 3)
under argon atmosphere (color of the reaction mixture turned to black). The
resulting mixture was stirred at room temperature (or at the indicated
temperature in Table 3). After completion of the reaction, to the reaction
mixture was added 4 mL of H2O (gas evolves). The aqueous layer was extracted
with CH2Cl2 (4 mL Â 2), and the combined organic layer was dried over Na2SO4
and evaporated. The residue was purified by silica gel column chromatography
using hexane/ethyl acetate as eluent.
7. Trialkylstannanes: Gutierrez, C. G.; Stringham, R. A.; Nitasaka, T.; Glasscock, K.
G. J. Org. Chem. 1980, 45, 3393–3395.
8. Zn/HCl: Baldwin, J. J.; Engelhardt, E. L.; Hirschmann, R.; Ponticello, G. S.;
Atkinson, J. G.; Wasson, B. K.; Sweet, C. S.; Scriabine, A. J. Med. Chem. 1980, 23,
65–70.
9. Zn/AcOH/Ac2O: Yamazaki, C.; Arima, H.; Udagawa, S. J. Heterocycl. Chem. 1996,
33, 41–44.