2
504
D. Sakuma, H. Togo
LETTER
(3) Doyle, M. P.; Forbes, D. C. Chem. Rev. 1998, 98, 911.
while phenyl and pentyl groups did not provide any cy-
clized products at all, respectively (entries 12, 13). More-
over, it is obvious that the introduction of dialkyl groups
to the 4-position or 5-position of 5-iodo-2-pentenoate
esters promotes the radical 3-exo-trig cyclization (entries
(
4) (a) Simmons, H. E.; Smith, R. D. J. Am. Chem. Soc. 1958,
0, 5323. (b) Simmons, H. E.; Smith, R. D. J. Am. Chem.
8
Soc. 1959, 81, 4256. (c) Furukawa, J.; Kawabata, N.;
Nishimura, J. Tetrahedron 1968, 24, 53.
(
5) (a) Phenyl(trihalomethyl)mercury with olefins: Seyferth, D.;
Burlitch, J. M.; Heeren, J. K. J. Org. Chem. 1962, 27, 1491.
(b) Seyferth, D.; Minasz, R. J.; Treiber, A. J. H.; Burlitch, J.
M.; Dowed, S. R. J. Am. Chem. Soc. 1963, 28, 1163.
4
–6). However, the introduction of a monoalkyl group to
the 4- or 5-position of 5-iodo-2-pentenoate esters reduces
dramatically the cyclization product, similar to the parent
5
effect, which was observed for the radical 4-exo-trig
cyclization of 6-bromo-2-hexenoate ester with Bu SnH.
(
c) Dialkylhalomethylaluminium with olefins: Hoberg, H.
-iodo-2-pentenoate esters (entries 1–3). This is the same
Angew. Chem. 1961, 73, 114. (d) Miller, D. B. Tetrahedron
Lett. 1964, 989. (e) Michael addition-initiated ring closure:
Bestmann, H. J.; Seng, F. Angew. Chem. 1962, 74, 154.
8
3
Thus, introduction of two alkyl groups to the 4- or 5-posi-
tion of 2-pentenoate esters is important for the efficient 3-
exo-trig cyclization. Instead of an activated olefinic
group, radical 3-exo-trig cyclization onto an electron-de-
ficient formyl group proceeded effectively to form the
corresponding cyclopropanol in good yield (entry 11).
(
f) Little, R. D.; Dawson, J. R. Tetrahedron Lett. 1980, 21,
2609. (g) Artaud, I.; Seyden-Penne, J.; Viout, P. Synthesis
1980, 34. (h) Bhattacharjee, S. S.; Ila, H.; Junjappa, H.
Synthesis 1982, 301.
(
i) Isopropylidenetriphenylphosphorane with olefins: Krief,
A.; Froidbise, A. Tetrahedron 2004, 60, 7637.
6) Nonhebel, D. C. Chem. Soc. Rev. 1993, 347.
(
Thus, an efficient, simple, and environmentally benign
preparation of cyclopropanes from electron-deficient 2-
iodoethyl-substituted olefins with zinc powder was suc-
cessfully achieved with high yields.
(7) (a) Giese, B. Radicals in Organic Synthesis: Formation of
Carbon-Carbon Bonds; Baldwin, J. E., Ed.; Pergamon
Press: Oxford, 1986. (b) Togo, H. Advanced Free Radical
Reactions for Organic Synthesis; Elsevier: Amsterdam,
2004.
(
8) (a) Jung, M. E.; Trifunovich, I. D.; Lensen, N. Tetrahedron
Lett. 1992, 33, 6719. (b) Jung, M. E.; Kiankarimi, M. J. Org.
Chem. 1995, 60, 7013. (c) Jung, M. E.; Marquez, R.
Tetrahedron Lett. 1997, 38, 6521.
Typical Experimental Procedure19
Zinc powder (1.2 mmol, 78.5 mg, used as received) was added to a
refluxing solution of 5-iodo-4,4-dimethyl-1-phenyl-2-penten-1-one
(9) Jung, M. E.; Kiankarimi, M. J. Org. Chem. 1995, 60, 7013.
(10) Gassman, P. G.; Lee, C. Tetrahedron Lett. 1989, 30, 2175.
(11) Wessig, P.; Mühling, O. Angew. Chem. Int. Ed. 2001, 40,
1064.
(12) Barton, D. H. R.; Basu, N. K.; Hesse, R. H.; Morehouse, F.
S.; Pechet, M. M. J. Am. Chem. Soc. 1966, 88, 3016.
(13) (a) David, H.; Afonso, C.; Bonin, M.; Doisneau, G.;
Guillerez, M.-G.; Guibé, F. Tetrahedron Lett. 1999, 40,
8557. (b) Villar, H.; Guibé, F.; Aroulanda, C.; Lesot, P.
Tetrahedron: Asymmetry 2002, 13, 1465.
(
0.4 mmol, 125.7 mg) in a mixture of t-BuOH (2 mL) and H O (1
2
mL) under an argon atmosphere. After 4 h at the same temperature,
the mixture was filtered through Celite, then the solvent was re-
moved, and the residue was purified by preparative TLC or column
chromatography on silica gel (hexane–EtOAc = 4:1) to give a-(2,2-
dimethylcyclopropyl)acetophenone (63.3 mg) in 84% yield as an
–
1
1
oil. IR (neat): 2940, 1690, 750, 690 cm . H NMR (400 MHz,
CDCl ): d = 0.06 (1 H, t, J = 4.6 Hz), 0.56 (1 H, dd, J = 8.7, 4.6 Hz),
3
0
.94–1.02 (1 H, dddd, J = 8.7, 7.2, 7.0, 4.6 Hz), 1.06 (3 H, s), 1.11
(
3 H, s), 2.93 (1 H, dd, J = 17.0, 7.2 Hz), 3.03 (1 H, dd, J = 17.0, 7.0
(14) (a) Villar, H.; Guibé, F. Tetrahedron Lett. 2002, 43, 9517.
(b) Bezzenine-Lafollée, S.; Guibé, F.; Villar, H.; Zriba, R.
Tetrahedron 2004, 60, 6931.
(15) Sugi, M.; Sakuma, D.; Togo, H. J. Org. Chem. 2003, 68,
7629.
1
3
Hz), 7.46 (2 H, m), 7.55 (1 H, tt, J = 7.4, 1.6 Hz), 7.96 (2 H, m).
NMR (100 MHz, CDCl ): d = 200.3 (q), 137.0 (q), 132.8 (t), 128.5
(
C
3
t), 128.0 (t), 39.2 (s), 27.1 (p), 20.2 (p), 19.8 (s), 19.6 (t), 15.4 (q).
MS (FAB): m/z = 189. HRMS (FAB): m/z calcd for C H O [M +
1
3
17
H]: 189.1279; found: 189.1268
(16) (a) Yamazaki, O.; Togo, H.; Matsubayashi, S.; Yokoyama,
M. Tetrahedron Lett. 1998, 39, 1921. (b) Yamazaki, O.;
Togo, H.; Matsubayashi, S.; Yokoyama, M. Tetrahedron
1999, 55, 3735. (c) Yamazaki, O.; Togo, H.; Yokoyama, M.
J. Chem. Soc., Perkin Trans. 1 1999, 2891. (d) Yamazaki,
O.; Togo, H.; Yamaguchi, K.; Yokoyama, M. J. Org. Chem.
Acknowledgment
Financial support from a Grant-in-Aid for Scientific Research
16655012) by the Ministry of Education, Science, Sports and
(
2000, 65, 5440. (e) Togo, H.; Matsubayashi, S.; Yamazaki,
Culture is gratefully acknowledged.
O.; Yokoyama, M. J. Org. Chem. 2000, 65, 2816.
(
(
f) Ryokawa, A.; Togo, H. Tetrahedron 2001, 57, 5915.
g) Sugi, M.; Togo, H. Tetrahedron 2002, 58, 3171.
References
(
17) (a) Griller, D.; Ingold, K. U. Acc. Chem. Res. 1980, 13, 317.
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1976, 98, 7024.
(
1) Review: Donaldson, W. A. Tetrahedron 2001, 57, 8589; and
most of synthetic approach to cyclopropanes that are cited
therein.
(18) (a) Chatgilialoglu, C.; Dickhaut, J.; Giese, B. J. Org. Chem.
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(
c) Dave, V.; Warnhoff, E. W. Org. React. 1970, 18, 217.
(19) All compounds gave satisfactory spectroscopic data.
Synlett 2004, No. 14, 2501–2504 © Thieme Stuttgart · New York