394
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 2, February, 2010
et al.
factors. H and 13C NMR spectra were recorded on a Bruker
ACꢀ250 spectrometer in CDCl3 under standard conditions.
GCꢀMS analysis was carried out on a Finnigan MAT ITDꢀ700
spectrometer (EI, 70 eV, ionic source—ionic trap temperature
220 °C) and a Carlo Erba 4200 chromatograph fitted with an
Ultraꢀ1 column (HewlettꢀPackard, 2500×0.2 mm, polymethylꢀ
siloxane stationary phase, layer thickness 0.33 μm, helium as
a carrier gas). The starting secondary alcohols (pentanꢀ3ꢀol (1a),
heptanꢀ4ꢀol (1b), nonanꢀ5ꢀol (1c), 2,4ꢀdimethylpentanꢀ3ꢀol
(1d), 3,3ꢀdimethylbutanꢀ2ꢀol (1e), 1ꢀphenylhexanꢀ1ꢀol (1f),
and 1ꢀphenylpropanꢀ1ꢀol (1g)) and cerium ammonium nitrate
(Acros) were used as purchased. Freshly distilled acetonitrile
(highꢀpurity grade) was used. Lithium bromide (highꢀpurity
grade) was calcined before use.
(C(CH3)3); 206.16 (CO). MS, m/z: 179 [M + H]+ (79Br); 181
1
[M + H]+ (81Br).
1
2ꢀBromoꢀ1ꢀphenylpropanꢀ1ꢀone (3f) (cf. Ref. 18). H NMR
(CDCl3), δ: 1.89 (d, 3 H, CH3, J = 7.0 Hz); 5.29 (m, 1 H,
CHBr); 7.48 (d, 2 H, H(2), H(4), J = 9.0 Hz); 7.62 (m, 1 H,
H(3)); 8.02 (d, 2 H, H(2), H(1), H(5), J = 9.0 Hz). 13C NMR
(CDCl3), δ: 19.25 (CH3); 41.20 (CHBr); 127.94 (C(1); C(5));
128.10 (C(2); C(4)); 133.93 (C(6)); 134.05 (C(3)); 192.64 (CO).
MS, m/z: 213 [M + H]+ (79Br); 215 [M + H]+ (81Br).
1
2ꢀBromoꢀ1ꢀphenylhexanꢀ1ꢀone (3g) (cf. Ref. 19). H NMR
(CDCl3), δ: 0.92 (m, 3 H, CH3); 1.43 (m, 2 H, CH2); 1.53
(m, 2 H, CH2); 2.18 (m, 2 H, CH2); 5.15 (t, 1 H, CHBr,
J = 7.5 Hz); 7.50 (d, 2 H, H(2), H(4), J = 9.0 Hz); 7.61 (m, 1 H,
H(3)); 8.03 (d, 2 H, H(1); H(5), J = 9.0 Hz). 13C NMR (CDCl3),
δ: 13.90 (CH3); 22.26 (CH2); 29.64 (CH2); 33.30 (CH2); 47.32
(CHBr); 128.15 (C(1), C(5)); 128.85 (C(2), C(4)); 133.67 (C(3));
134.60 (C(6)); 193.35 (CO). MS, m/z: 255 [M + H]+ (79Br); 257
[M + H]+ (81Br).
2,4ꢀDibromopentanꢀ3ꢀone (4a) (cf. Ref. 20). mesoꢀIsomer.
1H NMR (CDCl3), δ: 1.77 (d, 6 H, 2 CH3, J = 6.0 Hz); 4.76
(m, H, CHBr). 13C NMR (CDCl3), δ: 19.72 (2 CH3); 43.21
(2 CHBr); 196.06 (CO). racꢀIsomer. 1H NMR (CDCl3), δ: 1.81
(d, 6 H, 2 CH3, J = 6.0 Hz); 4.98 (m, 2 H, CHBr). 13C NMR
(CDCl3), δ: 21.78 (2 CH3); 44.35 (2 CH); 198.34 (CO). MS,
m/z: 244 [M + H]+ (79Br); 246 [M + H]+ (81Br).
Oxidation of alcohols (1a—f) with the system CAN—LiBr in
MeCN—H2O. A mixture of alkanol 1, CAN, and LiBr (their
ratios are specified in Tables 1 and 2) in 80% aqueous MeCN (15 mL)
was vigorously stirred with a magnetic stirring bar at 65 °C until the
oxidant was completely consumed (this was indicated by a color
change from orange to light yellow). The product was extracted
with ether (3×25 mL). The combined extracts were washed with
a saturated solution of NaHCO3 and water, dried over MgSO4,
and concentrated. The yields of the products and the converꢀ
sions of alkanol 1 were determined by GLC (see Tables 1, 2).
The products were isolated by column chromatography on silica
gel (L 40/100 μm) with hexane—ethyl acetate as an eluent.
Ketones (pentanꢀ3ꢀone (2a), heptanꢀ4ꢀone (2b), nonanꢀ5ꢀ
one (2c), 2,4ꢀdimethylpentanꢀ3ꢀone (2d), 3,3ꢀdimethylbutanꢀ
2ꢀone (2e), 1ꢀphenylpropanꢀ1ꢀone (2f), and 1ꢀphenylhexanꢀ1ꢀ
one (2g)) were identified by IR and NMR spectroscopy and by
comparison with authentic samples.
2ꢀBromopentanꢀ3ꢀone (3a) (cf. Ref. 13). 1H NMR (CDCl3),
δ: 1.12 (t, 3 H, CH3, J = 7.3 Hz); 1.75 (d, 3 H, CH3CHBr,
J = 6.8 Hz); 2.59 (m, 2 H, CH2); 4.42 (m, 1 H, CHBr). 13C NMR
(CDCl3), δ: 8.29 (CH3); 20.26 (CH3CHBr); 32.04 (CH2); 47.39
(CHBr); 205.13 (CO). MS, m/z: 165 [M + H]+ (79Br), 167
[M + H]+ (81Br).
3ꢀBromoheptanꢀ4ꢀone (3b) (cf. Ref. 14). 1H NMR (CDCl3),
δ: 0,91 (t, 3 H, CH3, J = 7.5 Hz); 1.00 (t, 3 H, CH3, J = 7.5 Hz);
1.61 (m, 2 H, CH2); 1.99 (m, 2 H, CH2Br); 2.34 (t, 2 H, CH2CO,
J = 7.3 Hz); 4.16 (m, 1 H, CHBr). 13C NMR (CDCl3), δ: 11.94
(CH3); 13.65 (CH3); 17.35 (CH2); 26.86 (CH2Br); 40.90 (CH2CO);
55.47 (CHBr); 204.16 (CO). MS, m/z: 193 [M + H]+ (79Br); 195
[M + H]+ (81Br).
4ꢀBromononanꢀ5ꢀone (3c) (cf. Ref. 15). 1H NMR (CDCl3),
δ: 0.89 (t, 3 H, CH3, J = 6.4 Hz); 0.94 (t, 3 H, CH3, J = 6.4 Hz);
1.36 (m, 2 H, CH2); 1.49 (m, 2 H, CH2); 1.62 (m, 2 H, CH2);
1.92 (m, 2 H, CH2CHBr); 2.68 (t, 2 H, CH2CO, J = 7.0 Hz);
4.25 (t, 1 H, CHBr, J = 7.5 Hz). 13C NMR (CDCl3), δ: 1.75
(CH3); 14.82 (CH3); 20.86 (CH2); 22.50 (CH2); 25.92 (CH2);
34.40 (CH2CHBr); 43.85 (CH2CO); 54.08 (CHBr); 207.93 (CO).
MS, m/z: 221 [M + H]+ (79Br); 223 [M + H]+ (81Br).
2ꢀBromoꢀ2,4ꢀdimethylpentanꢀ3ꢀone (3d) (cf. Ref. 16). 1H
NMR (CDCl3), δ: 1.23 (d, 6 H, 2 CH3, J = 6.5 Hz); 1.88 (s, 6 H,
2 CH3); 3.46 (m, 1 H, CHCO). 13C NMR (CDCl3), δ: 18.75 (CH3);
18.80 (CH3); 29.35 (CH3); 29.47 (CH3); 34.62 (CH(CH3)2);
64.66 (CBr(CH3)2); 210.08 (CO). MS, m/z: 193 [M + H]+ (79Br);
195 [M + H]+ (81Br).
3,5ꢀDibromoheptanꢀ4ꢀone (4b) (cf. Ref. 21). mesoꢀIsomer.
1H NMR (CDCl3), δ: 1.05 (t, 6 H, 2 CH3, J = 6.0 Hz); 1.97
(m, 4 H, 2 CH2); 4.52 (t, 2 H, CHBr, J = 7.5 Hz). 13C NMR
(CDCl3), δ: 9.59 (2 CH3); 26.47 (2 CH2); 51.69 (2 CHBr); 194.27
1
(CO). racꢀIsomer. H NMR (CDCl3), δ: 1.05 (t, 6 H, 2 CH3);
2.09 (m, 4 H, 2 CH2); 4.65 (t, 2 H, CHBr, J = 7.5 Hz). 13C NMR
(CDCl3), δ: 9.77 (2 CH3); 28.16 (2 CH2); 52.30 (2 CHBr); 197.50
(CO). MS, m/z: 272 [M + H]+ (79Br); 274 [M + H]+ (81Br).
4,6ꢀDibromononanꢀ5ꢀone (4c) (cf. Ref. 22). mesoꢀIsomer.
1H NMR (CDCl3), δ: 1.01 (t, 6 H, 2 CH3, J = 6.0 Hz); 1.48
(m, 4 H, 2 CH2); 1.96 (m, 4 H, 2 CH2); 4.60 (t, 2 H, CHBr,
J = 7.5 Hz). 13C NMR (CDCl3), δ: 13.41 (2 CH3); 20.61 (2 CH2);
35.00 (2 CH2); 50.13 (2 CHBr); 194.36 (CO). racꢀIsomer.
1H NMR (CDCl3), δ: 1.01 (t, 6 H, 2 CH3, J = 6.0 Hz); 1.51
(m, 4 H, 2 CH2); 1.98 (m, 4 H, 2 CH2); 4.73 (t, 2 H, CHBr,
J = 7.5 Hz). 13C NMR (CDCl3), δ: 13.51 (2 CH3); 20.91
(2 CH2); 36.35 (2 CH2); 53.58 (2 CHBr); 197.75 (CO). MS, m/z:
300 [M + H]+ (79Br); 302 [M + H]+ (81Br).
1,1ꢀDibromoꢀ3,3ꢀdimethylbutanꢀ2ꢀone (4e) (cf. Ref. 20).
1H NMR (CDCl3), δ: 1.38 (s, 9 H, 3 CH3); 6.35 (s, 1 H, CHBr2).
13C NMR (CDCl3), δ: 26.56 (3 CH3); 37.44 (CHBr); 44.08
(C(CH3)3); 201.63 (CO). MS, m/z: 258 [M + H]+ (79Br); 260
[M + H]+ (81Br).
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 09ꢀ03ꢀ00292a)
and the Council on Grants at the President of the Rusꢀ
sian Federation (Program for State Support of Leading
Scientific Schools of the Russian Federation, Grant
2942.2008.3).
References
1ꢀBromoꢀ3,3ꢀdimethylbutanꢀ2ꢀone (3e) (cf. Ref. 17). 1H NMR
(CDCl3), δ: 1.21 (s, 9 H, CH3); 4.16 (s, 2 H, CH2BrCO).
13C NMR (CDCl3), δ: 26.42 (3 CH3); 31.84 (CH2Br); 44.26
1. W. S. Trahanovsky, L. B. Young, J. Chem. Soc., 1965, 5777.
2. W. S. Trahanovsky, L. B. Young, Tetrahedron Lett.,
1969, 2501.