CDCl3) δ 0.88 (6 H, t, J 7.2, Me), 1.23–1.42 (8 H, m, CH2), 2.18
(4 H, t, J 7.8, CH –C᎐C). 13C NMR (CCl4–CDCl3) δ 14.08,
2.42 (1 H, m). 13C NMR (CCl4–CDCl3) δ 14.76 (Me), 19.15
(Me), 19.98 (Me), 27.60, 33.56, 44.26, 44.72, 50.64 (C-1 or C-7),
᎐
2
22.74, 29.51, 36.04, 85.62 (CBr ), 146.19 (–C᎐).
56.50 (C-1 or C-7), 76.64 (CBr ), 152.82 (–C᎐). MS (EI, 70 eV);
᎐
᎐
2
2
m/z (%): 308 (Mϩ, 29), 265 (21, C8H9Br2), 252 (61, C7H8Br2),
227 (15, Mϩ Ϫ Br), 185 (18, C8H9Br), 171 (30, C7H8Br), 158 (19,
C6H6Br), 148 (100, Mϩ Ϫ 2Br), 105 (52, C8H9), 91 (51, C7H7).
(2,2-Dibromo-1-methylvinyl)cyclopropane (6). Prepared from
methyl cyclopropyl ketone. Colourless oil, Rf (hexane) 0.80.13
(Dibromomethylene)cyclopentane (7). Prepared from cyclo-
pentanone. Colourless oil, Rf (hexane) 0.80.14
Acknowledgments
Financial support from the Russian Foundation for Basic
Research (Grants N 03–03–32046 and 03–03–32052) is grate-
fully acknowledged.
(Dibromomethylene)cyclohexane (8). Prepared from cyclo-
hexanone. Colourless oil, Rf (hexane) 0.75.14
(Dibromomethylene)cycloheptane (9). Prepared from cyclo-
heptanone. Colourless oil, Rf (hexane) 0.80.15
References
1 S. E. Kelly, in Comprehensive Organic Synthesis, ed. B. M. Trost and
I. Fleming, Pergamon Press, New York, 1999, pp. 730–810.
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E. S. Balenkova, Tetrahedron, 2000, 56, 6557–6563; (b) A. V. Shastin,
V. N. Korotchenko, V. G. Nenajdenko and E. S. Balenkova,
Russ. Chem. Bull., 2001, 50, 1401–1404; (c) V. N. Korotchenko,
A. V. Shastin, V. G. Nenajdenko and E. S. Balenkova, Tetrahedron,
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3 E. J. Corey and P. L. Fuchs, Tetrahedron Lett., 1972, 36, 3769–3772.
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(b) L. Van Hijfte, M. Kolb and P. Witz, Tetrahedron Lett., 1989, 30,
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(Dibromomethylene)cyclooctane (10). Prepared from cyclo-
octanone. Colourless oil, Rf (hexane) 0.80. Found: C, 38.15; H,
4.77. Calcd for C9H14Br2: C, 38.33; H, 5.00%. 1H NMR (CCl4–
CDCl3) δ 1.37–1.49 (6 H, m, CH2), 1.65–1.72 (4 H, m, CH2),
2.32 (t, J 6.2, 4 H, CH –C᎐C). 13C NMR (CCl4–CDCl3) δ 25.22,
᎐
2
25.61, 27.05, 35.47, 84.41 (CBr ), 147.05 (–C᎐).
᎐
2
2-(Dibromomethylene)-1-isopropyl-4-methyl cyclohexane (11).
Prepared from menthone. Was obtained as a mixture of
diastereomers in a 6 : 1 ratio. Colourless oil, Rf (hexane) 0.80.
Found: C, 42.32; H, 5.86. Calcd for C11H18Br2: C, 42.61; H,
5.85%. 1H NMR (CCl4–CDCl3), Major isomer: δ 0.78 (3 H, d,
J 6.7), 0.89 (6 H, m), 1.10–1.17 (1 H, m), 1.55–1.92 (4 H, m),
2.02–2.09 (2 H, m), 2.52–2.65 (2 H, m). Minor isomer: δ 2.42–
2.52 (2 H, m), 3.01 (1 H, hept, J 6.9). Other signals of the minor
isomer were overlapped by signals of the major isomer. 13C
NMR (CCl4–CDCl3) δ 17.60, 19.71, 20.09, 20.48, 20.95, 21.33,
22.97, 25.08, 26.40, 27.48, 30.30, 30.88, 31.18, 33.80, 36.61,
45.29, 49.61, 83.93 (CBr ), 139.37 (–C᎐), 145.43 (–C᎐).
᎐
᎐
2
6 (a) J. Uenishi, R. Kawahama, O. Yonemitsu and J. Tsuji, J. Org.
Chem., 1996, 61, 5716–5717; (b) S. Abbas, C. J. Hayes and
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7 W. Shen and L. Wang, J. Org. Chem., 1999, 64, 8873–8879.
8 F. Ramirez, N. B. Desai and N. McKelvie, J. Am. Chem. Soc., 1962,
84, 1745–1747.
MS (EI, 70 eV); m/z (%): major isomer: 310 (Mϩ, 29), 267 (87,
Mϩ Ϫ C3H7), 229 (5, Mϩ Ϫ Br), 187 (45, Mϩ Ϫ Br Ϫ C3H7), 149
(50, Mϩ Ϫ 2Br Ϫ H), 106 (100, Mϩ Ϫ 2Br Ϫ C3H8), 91 (63,
C7H7). Minor isomer: 310 (12, Mϩ), 267 (57, Mϩ Ϫ C3H7), 229
(6, Mϩ Ϫ Br), 187 (50, Mϩ Ϫ Br Ϫ C3H7), 149 (51, Mϩ Ϫ 2Br Ϫ
H), 106 (100, Mϩ Ϫ 2Br Ϫ C3H8), 91 (64, C7H7).
9 G. H. Posner, G. L. Loomis and H. S. Sawaya, Tetrahedron Lett.,
1975, 1373–1376.
10 M. Rule, J. A. Mondo and J. A. Berson, J. Am. Chem. Soc., 1982,
104, 2209–2216.
11 K. Naumann, Synthetic Pyrethroid Insecticides: Structures and
Properties, Ser. Chemistry of Plant protection. V. 4., Springer-
Verlag, Berlin, 1990, 241 pp.
12 N. Kishner, J. Russ. Phys. Chem. Soc., 1911, 43, 582–595.
13 P. Entmayr and G. Koebrich, Chem. Ber., 1976, 109, 2175–2184.
14 T. N. Mitchell and W. Reimann, Organometallics, 1986, 5, 1991–
1997.
15 P. Savignac and P. Coutrot, Synthesis, 1976, 197–199.
16 G. A. Olah and A. H. Wu, Synthesis, 1990, 885–886.
2-(Dibromomethylene)adamantane (12). Prepared from
adamantanone. Rf (hexane) 0.80.16
2-(Dibromomethylene)-1,7,7-trimethylbicyclo[2.2.1]heptane
(13). Prepared from the hydrazone of (ϩ)-camphor. Rf (hexa-
ne) 0.75. Found: C, 42.61; H, 5.34. Calcd for C11H16Br2: C,
42.89; H, 5.24%. 1H NMR (CCl4–CDCl3) δ 0.80 (3 H, s, 7-Me),
0.84 (3 H, s, 7-Me), 1.06 (1H, d, J 8.5), 1.24 (3 H, s, 1-Me), 1.47–
1.53 (2 H, m), 1.71–1.74 (2 H, m), 1.87 (1 H, d, J 16.7), 2.32–
O r g . B i o m o l . C h e m . , 2 0 0 3 , 1, 1 9 0 6 – 1 9 0 8
1908