7
04
H. Togo, T. Hirai
LETTER
Table 3 Monobromination and Dibromination of Diethyl Iso-
propylidenemalonate with Solvent-Free System
(2) Recent reports: (a) Hartman, G.; Halczenko, W.; Phillips, B.
T. J. Org. Chem. 1986, 51, 142. (b) Stevens, C. V.; Heecke,
G. V.; Barbero, C.; Patora, K.; De Kimpe, N.; Verhe, R.
Synlett 2002, 1089. (c) Ojida, A.; Park, S.-K.; Mito-oka, Y.;
Hamachi, I. Tetrahedron Lett. 2002, 43, 6193. (d) Sygula,
A.; Karlen, S. D.; Sygula, R.; Rabideau, P. W. Org. Lett.
CH3
CO Et
BrCH2
CO2Et BrCH2
+
CO2Et
2
Conditions
solvent-free
CH3 CO Et
CH3
CO Et BrCH2
CO Et
2
2
2
1
2
2002, 4, 3135. (e) Ma, S.; Ni, B. J. Org. Chem. 2002, 67,
8280. (f) Mehta, G.; Sarma, P. V. V. S. Tetrahedron Lett.
2002, 43, 9343.
NBS
Initiator
Conditions
Yields (%)
1
2
(
3) Review: (a) Loupy, A.; Petit, A.; Hamelin, J.; Texier-
Boullet, F.; Jacquault, P.; Mathe, D. Synthesis 1998, 1213.
monobromination
(
b) Recent report: Sharghi, H.; Hosseini, M. Synthesis 2002,
057. (c) Melucci, M.; Barbarella, B.; Sotgiu, G. J. Org.
Chem. 2002, 67, 8877.
(4) Reviews: (a) Welton, T. Chem. Rev. 1999, 99, 2071.
b) Wasserscheid, P.; Keim, W. Angew. Chem. Int. Ed. 2000,
9, 3772. (c) Sheldon, R. Chem. Commun. 2001, 2399.
d) Sheldon, R. A. Pure Appl. Chem. 2000, 72, 1233.
1
1.05 equiv (PhCO ) : 0.04 equiv
90 °C, 20 min
65 °C, 2 h
67 12
76 15
2
2
1.2 equiv
AIBN: 0.1 equiv
(
3
(
dibromination
2
.1 equiv
.4 equiv
(PhCO ) : 0.08 equiv
90 °C, 2 h
65 °C, 4 h
13 43
2
2
(
5) (a) Recent reports selected: Ren, R. X.; Zueva, L. D.; Ou, W.
Tetrahedron Lett. 2001, 42, 8441. (b) Morrison, D. W.;
Forbes, D. C.; Davis, J. H. Jr. Tetrahedron Lett. 2001, 42,
2
AIBN: 0.2 equiv
7
62
6053. (c) Mayo, K. G.; Nearhoof, E. H.; Kiddle, J. J. Org.
Lett. 2002, 4, 1567. (d) Yanada, R.; Takemoto, Y.
Tetrahedron Lett. 2002, 43, 6849. (e) Ansari, I. A.; Gree, R.
Org. Lett. 2002, 4, 1507. (f) Fukuyama, T.; Shinmen, M.;
Nishitani, S.; Sato, M.; Ryu, I. Org. Lett. 2002, 4, 1691.
Acknowledgement
Financial support from a Grant-in-Aid for Scientific Research (No.
3554028) from the Ministry of Education, Science, Sports and
(
1
g) Xie, Y.-Y.; Chen, Z.-C.; Zheng, Q.-G. Synthesis 2002,
505.
1
Culture of Japan, and Futaba Electronics Memorial Foundation are
gratefully acknowledged.
(
6) (a) Yamazaki, O.; Togo, H.; Matsubayashi, S.; Yokoyama,
M. Tetrahedron 1999, 55, 3735. (b) Yamazaki, O.;
Yamaguchi, K.; Yokoyama, M.; Togo, H. J. Org. Chem.
2
000, 65, 5440. (c) Togo, H.; Matsubayashi, S.; Yamazaki,
O.; Yokoyama, M. J. Org. Chem. 2000, 65, 2816.
d) Yamazaki, O.; Togo, H.; Yokoyama, M. J. Chem. Soc.,
References
(
(
1) (a) March, J. In Advanced Organic Chemistry, 4th Ed.;
Willey & Sons: New York, 1992, Chap. 14, and references
are cited therein. (b) Dauben, H. J. Jr.; McCoy, L. L. J. Am.
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Tanner, D. D. J. Am. Chem. Soc. 1963, 85, 3129.
Perkin Trans 1. 1999, 2891. (e) Atsushi, R.; Togo, H.
Tetrahedron 2001, 57, 5915. (f) Sugi, M.; Togo, H.
Tetrahedron 2002, 58, 3171.
(
7) (a) Co(I)-mediated living radical polymerization:
Carmichael, A. J.; Haddleton, D. M.; Bon, S. A. F.; Seddon,
K. R. Chem. Commun. 2000, 1237. (b) Triethylborane-
induced radical cyclizations with Bu SnH: Yorimitsu, H.;
Oshima, K. Bull. Chem. Soc. Jpn. 2002, 75, 853.
8) (a) Chapman, N. B.; Williams, J. F. A. J. Chem. Soc. 1952,
(
d) Greenwood, F. L.; Kellert, M. D.; Sedlak, J. Org. Synth.,
Coll. Vol. 4 1963, 108. (e) Campaigne, E.; Tullar, B. F. Org.
Synth., Col. Vol. 4 1963, 921. (f) Cram, D. J.; Helgeson, R.
C. J. Am. Chem. Soc. 1966, 88, 3515.
3
(
5044. (b) Mitchell, R. H.; Lai, Y.-H.; Williams, R. V. J. Org.
Chem. 1979, 44, 4733.
Synlett 2003, No. 5, 702–704 ISSN 0936-5214 © Thieme Stuttgart · New York