A. Chojnacka et al. / Tetrahedron: Asymmetry 18 (2007) 101–107
105
those referred earlier in the literatures 2,19 3,20 4,21 and 5.22
Here, only the yields of the reactions and refractive indexes
of alcohols obtained are given.
J = 7.6 Hz, 3H, –C(O)CH2CH3), 1.41 (ddd, J = 13.2, 7.3,
5.7 Hz, 1H, one of –CH2CH(CH3)2), 1.58–1.70 (m, 2H,
–CH(CH3)2 and one of –CH2CH(CH3)2), 2.35 (q,
J = 7.6 Hz, 2H, –C(O)CH2CH3), 5.16 (d, J = 10.5 Hz,
1H, one of –CH@CH2), 5.25 (d, J = 17.2 Hz, 1H, one of
–CH@CH2), 5.35 (m, 1H, –OCH), 5.79 (ddd, J = 17.2,
10.5, 6.4 Hz, 1H, –CH@CH2).
( )-5-Methylhex-1-en-3-ol 2: yield 60%, colorless liquid,
n2D0 ¼ 1:4230 {lit.29 n2D1 ¼ 1:4251}.
( )-6-Methylhept-2-en-4-ol 3: yield 62%, colorless liquid,
n2D0 ¼ 1:4385 {lit.20 n2D1 ¼ 1:4359}.
3.4.4. 3-Methyl-1-vinyl-butyl butanoate 9. Yield 79%, col-
orless liquid, nD20 ¼ 1:4222; IR (film) mmax (cmꢀ1) = 1741 (s,
C@O), 1178 (s, C–O), 990 (m, @C–H); 1H NMR (CDCl3):
d 0.89 and 0.92 (two d, J = 6.5 Hz, 6H, –CH(CH3)2), 0.95
(t, J = 7.4 Hz, 3H, –C(O)(CH2)2CH3), 1.38 (ddd, J = 13.5,
7.6, 5.8 Hz, 1H, one of –CH2CH(CH3)2), 1.58 (ddd,
J = 13.5, 7.6, 6.3 Hz, 1H, one of –CH2CH(CH3)2), 1.61–
1.71 (m, 3H, –CH(CH3)2 and –C(O)CH2CH2CH3), 2.29
(t, J = 7.4 Hz, 2H, –C(O)CH2CH2CH3), 5.13 (d, J =
10.5 Hz, 1H, one of –CH@CH2), 5.22 (d, J = 17.2 Hz,
1H, one of –CH@CH2), 5.32 (m, 1H, –OCH), 5.76
(ddd, J = 17.2, 10.5, 6.4 Hz, 1H, –CH@CH2).
( )-6,6-Dimethylhept-2-en-4-ol 4: yield 68%, colorless
liquid, n2D0 ¼ 1:4568 {lit.21 n2D0 ¼ 1:4576}.
( )-1-Phenylbut-3-en-2-ol 5: yield 75%, colorless liquid,
n2D0 ¼ 1:5162 {lit.22 n1D7 ¼ 1:5353}.
3.4. Preparation of racemic esters 6–15
Propionates and butanoates of alcohols 1–5 were obtained
as reference compounds for GC analyses in a standard
manner (reaction with propionyl chloride or butyryl chlo-
ride) according to the following procedure.
To a cooled (0 ꢁC, ice bath) solution of alcohols 1–5
(10 mmol) and pyridine (12 mmol) in dry diethyl ether
(10 mL), acyl chloride (12 mmol) was added dropwise
and the mixture was stirred at room temperature for
24 h. After that time, the reaction mixture was diluted with
diethyl ether and washed with 0.1 M aqueous HCl, satu-
rated NaHCO3, and finally with brine. The ether solution
was dried over MgSO4. The solvent was evaporated and
crude product was purified by column chromatography
(silica gel, hexane–ethyl acetate, 22:1).
3.4.5. 1-Isobutylbut-2-enyl propionate 10. Yield 78%, col-
orless liquid nD20 ¼ 1:4245; IR (film) mmax (cmꢀ1) = 1737
1
(s, C@O), 1189 (s, C–O); H NMR: d 0.88 and 0.90 (two
d, J = 6.3 Hz, 6H, –CH(CH3)2), 1.10 (t, J = 7.6 Hz, 3H,
–C(O)CH2CH3) 1.28 (m, 1H, one of –CH2CH(CH3)2),
1.50–1.60 (m, 2H, one of –CH2CH(CH3)2 and
–CH(CH3)2), 1.67 (dd, J = 6.7, 1.4 Hz, 3H@CH–CH3),
2.28 (q, J = 7.6 Hz, 2H, –C(O)CH2CH3), 5.25 (ddd,
J = 7.5, 7.0, 6.7 Hz, 1H, –OCH), 5.46 (ddq, J = 13.6,
7.5, 1.4 Hz, 1H, –CH@CHCH3), 5.62 (dqd, J = 13.6, 6.7,
0.6 Hz, 1H, @CHCH3).
The yields of the reactions, spectral data, and refractive in-
dexes for the esters obtained are given below.
3.4.6. 1-Isobutylbut-2-enyl butanoate 11. Yield 75%, col-
orless liquid, nD20 ¼ 1:4321; IR (film) mmax (cmꢀ1) = 1741
1
3.4.1. 1-Vinyl-pentyl propionate 6. Yield 81%, colorless li-
quid, n2D0 ¼ 1:4241; IR (film) mmax (cmꢀ1) = 1738 (s, C@O),
(s, C@O), 1192 (s, C–O), 992 (m, C–H); H NMR: d 0.89
and 0.92 (two d, J = 6.2 Hz, 6H, –CH(CH3)2), 1.12
(t, J = 7.5 Hz, 3H, –C(O)(CH2)2CH3), 1.22 (m, 2H,
–C(O)CH2CH2CH3), 1.30 (m, 1H, one of –CH2CH(CH3)2),
1.42–1.55 (m, 2H, one of –CH2CH(CH3)2 and
–CH(CH3)2), 1.70 (dd, J = 6.6, 1.3 Hz, 3H, =CH–CH3),
2.30 (t, J = 6.6 Hz, 2H, –C(O)CH2CH2CH3), 5.42 (ddq,
J = 13.5, 7.4, 1.3 Hz, 1H, —CH@CHCH3), 5.51 (ddd,
J = 7.4, 7.0, 6.7 Hz, 1H, –OCH), 5.60 (dqd, J = 13.5,
6.6, 0.6 Hz, 1H, @CHCH3).
1
1187 (s, C–O), 992 (m, =C–H); H NMR (CDCl3): d 0.85
(t, J = 6.8 Hz, 3H, –CH2CH3), 1.13 (t, J = 7.4 Hz, 3H,
–C(O)CH2CH3), 1.27–1.36 (m, 4H, CH3(CH2)2–), 1.47–
1.57 (m, 2H, –CH2–), 2.3 (q, J = 7.4 Hz, 2H, –C(O)-
CH2CH3), 5.07 (ddd, J = 10.5, 2.4, 1.4 Hz, 1H, one of
–CH@CH2), 5.19 (ddd, J = 17.3, 2.6, 1.4 Hz, 1H, one of
–CH@CH2), 5.2 (m, 1H, –OCH), 5.8 (ddd, J = 17.3,
10.5, 6.2 Hz, 1H, –CH@CH2).
3.4.2. 1-Vinyl-pentyl butanoate 7. Yield 86%, colorless li-
quid, n2D0 ¼ 1:4237 {lit.30 nD20 ¼ 1:4241}; IR (film) mmax
(cmꢀ1) = 1742 (s, C@O), 1182 (s, C–O), 996 (m, @C–H);
1H NMR (CDCl3): d 0.82 (t, J = 6.8 Hz, 3H, –CH2CH3),
1.15 (t, J = 7.4 Hz, 3H, –C(O)(CH2)2CH3), 1.25–1.38
(m, 4H, CH3(CH2)2–), 1.41–1.53 (m, 2H, –CH2–), 1.57
(m, 2H, –C(O)CH2CH2CH3), 2.3 (t, J = 7.4 Hz, 2H,
–C(O)CH2CH2CH3), 5.10 (ddd, J = 10.5, 2.4, 1.4 Hz,
1H, one of –CH@CH2), 5.2 (ddd, J = 17.3, 2.6, 1.4 Hz,
1H, one of –CH@CH2), 5.22 (m, 1H, –OCH), 5.8 (ddd,
J = 17.2, 10.5, 6.2 Hz, 1H, –CH@CH2).
3.4.7. 1-(2,2-Dimethylpropyl)but-2-enyl propionate 12.
Yield 78%, colorless liquid n2D0 ¼ 1:4425; IR (film) mmax
(cmꢀ1) = 1739 (s, C@O), 1192 (s, C–O), 990 (m, @C–H);
1H NMR: d 0.89 (s, 9H, –C(CH3)3), 1.12 (t, J = 7.6 Hz,
3H, –C(O)CH2CH3), 1.41 (dd, J = 15.0, 3.8 Hz, 1H, one
of –CH2C(CH3)3), 1.60 (dd, J = 15.0, 7.9, 1H, one of
–CH2C(CH3)3), 1.65 (dd, J = 6.5, 1.1 Hz, 3H, @CH–CH3),
2.26 (q, J = 7.6 Hz, 2H, –C(O)CH2CH3), 5.32 (m, 1H,
–OCH), 5.36 (ddq, J = 13.0, 8.7, 1.1, 1H, –CH@CHCH3),
5.60 (dq, J = 13.0, 6.5 Hz, 1H, @CHCH3).
3.4.8. 1-(2,2-Dimethylpropyl)but-2-enyl butanoate 13.
Yield 83%, colorless liquid, n2D0 ¼ 1:4395; IR (film) mmax
(cmꢀ1) = 1741 (s, C@O), 1195 (s, C–O), 986 (m, @C–H);
1H NMR: d 0.91 (s, 9H, –C(CH3)3), 1.1 (t, J = 7.4 Hz,
3H, –C(O)(CH2)2CH3), 1.26 (m, 2H, –C(O)CH2CH2CH3),
3.4.3. 3-Methyl-1-vinyl-butyl propionate 8. Yield 83%, col-
orless liquid, nD20 ¼ 1:4112; IR (film) mmax (cmꢀ1) = 1745 (s,
C@O), 1194 (s, C–O) 989 (m, @C–H); 1H NMR (CDCl3): d
0.93 and 0.94 (two d, J = 6.2 Hz, 6H, –CH(CH3)2), 1.16 (t,