M. K. Basu, B. K. Banik / Tetrahedron Letters 42 (2001) 187–189
189
reaction of imines and benzyl bromide was low and
dibenzyl was found to be the major product from the
reaction.15 However, addition of benzyl bromide to the
ketones by following our method afforded the benzyl
alcohol in an excellent yield, a small portion of which
was dimerized (entries 6–10). Thus, the involvement of
trivalent samarium species in this type of addition
reactions remains a question. Our study indicates that
pre-generated bivalent or trivalent samarium species is
not required for the Barbier addition of halides to
carbonyl compounds. We believe the formation of an
activated samarium-R reagent attacks the carbonyl
group in THF solution. Further studies are needed to
define the critical role of solvents in the samarium-
induced addition and dimerization of carbonyl com-
pounds in the presence of halides.
3. For example, see: Marton, D.; Stivanello, D.; Tagliavini,
G. J. Org. Chem. 1996, 61, 2731
4. (a) Barbot, F.; Miginiac, P. Tetrahedron Lett. 1975, 44,
3829. (b) Bernardon, C.; Deberly, A. J. Org. Chem. 1982,
47, 463.
5. Katritzky, A. R.; Shobana, N.; Harris, P. A.
Organometallics 19
92, 11, 1381 and references cited therein.
6. Li, C.-J.; Chan, T.-H. Tetrahedron 1999, 55, 11149 and
references cited therein.
7. (a) Girard, P.; Namy, J. L.; Kagan, H. B. J. Am. Chem.
Soc. 1980, 102, 2693. (b) Soupe, J.; Namy, J. L.; Kagan,
H. B. Tetrahedron Lett. 1982, 23, 3497.
8. (a) Murakami, M.; Hayashi, M.; Ito, Y. Synlett 1994,
179. (b) Ogawa, A.; Takeuchi, H.; Hirao, T. Tetrahedron
Lett. 1999, 40, 7113.
9. Yanada, R.; Negoro, N.; Okaniwa, M.; Ibuka, T. Tetra-
hedron 1999, 55, 13947 and references cited therein.
10. (a) Banik, B. K.; Mukhopadhyay, C.; Venkatraman, M.
S.; becker, F. F. Tetrahedron Lett. 1998, 39, 7243. (b)
Basu, M.; Becker, F. F.; Banik, B. K. Tetrahedron Lett.
2000, 41, 5603
11. Banik, B. K.; Zegrocka, O.; Banik, I.; Hackfeld, L.;
Becker, F. F. Tetrahedron Lett. 1999, 40, 6731.
12. Ghatak, A.; Becker, F. F.; Banik, B. K. Tetrahedron Lett.
2000, 41, 3793.
In comparison to all of the previous reports, the present
method is rapid, convenient and cost-saving. In conclu-
sion, we have demonstrated a general method for Bar-
bier-type addition reactions of aldehydes and ketones in
excellent yields at room temperature.16
Acknowledgements
13. Akane, N.; Hatano, T.; Kusui, H.; Nishiyama, Y.; Ishii,
Y. J. Org. Chem. 1994, 59, 7902.
14. Negoro, N.; Yanada, R.; Okaniwa, M.; Yanada, K.;
Fujita, T. Synlett 1998, 835.
15. Yanada, R.; Negoro, N.; Okaniwa, M.; Ibuka, T. Tetra-
This work was supported in part by a grant received
from the Robert J. Kleberg Jr. and Helen C. Kleberg
Foundation and an NIH Cancer Center Support Grant,
5-P30-CA16672-25, in particular the shared resources
of the Pharmacology and Analytic Center Facility.
hedron 1999, 55, 13947.
16. Typical procedure: Alkyl halide (1.50 mmol) was added
dropwise to samarium (1.50 mmol) (preactivated by heat-
ing with 0.05 mmol of iodine) in 4.0 mL dry THF under
an argon atmosphere at room temperature. A dark blue
or purple color was generated within 2–5 min. The
carbonyl compound (0.5 mmol) was added dropwise
while slowly maintaining the blue color of the reaction
mixture. The reaction mixture was stirred for 10–30 min
and then was quenched with 0.1N hydrochloric acid. The
resulting mixtures were extracted with CH2Cl2, dried over
sodium sulfate and evaporated to dryness. Finally, the
product was purified by column chromatography.
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